Skyscrapers retrofitting methodology and Energy assessment for different retrofitting solutions

POLITECNICO DI MILANO Scuola di Architettura Urbanistica Ingegneria delle Costruzioni

Skyscrapers retrofitting methodology and Energy assessment for different retrofitting solutions Torre GALFA retrofitting and energy assesment study

Master thesis by: Awad Ahmed 850610 Supervisors: Prof. Nastri Massimiliano

AA 2017/2018

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Abstract

The study intends to examine retrofitting methodology using different bioclimatic design solution and simulate the energy assessment as an effect of each design solution. The skyscraper specified in particular the ones in northern Europe built in the last century which have technically dysfunctional and deteriorating facade components leading to extensive degradation inflicted on the natural environment ecological sustainability through high energy consumption. Undoubtedly, these intensive commercial and institutional urban buildings are indeed energy guzzlers, consuming huge amounts of materials in their construction and making massive volumes of waste discharge into the environment, these days buildings are responsible for 40% of energy consumption and 36% of CO2 emissions in the EU. The major objective is to define this methodology to redesign the composite skins wrapped around and hung on a building’s concrete or steel skeleton. Connected to but structurally independent of the skeleton in order to reduce the conventional energy consumption for heating, cooling, lighting and air quality, with an improvement in thermal comfort conditions.

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The first step consists of the reason of choosing skyscrapers with introducing to such building types and its design aspects in general.

Despite the topic is really up to date in the national and international investigations, with recent publication of new studies, unfortunately it’s still quite difficult to obtain a complete methodology works on evaluation for the skyscrapers to see how is it affecting the environment, also regarding to energy-saving reasons. This is because skyscrapers built in northern Europe in that period were not designed with ‘green’ or ecologically responsive design objectives in mind. Indeed, these must certainly now are the prime objectives for the design community today. After defining skyscrapers design elements and in order to understand its effect on the building’s energy consumption the building’s energy loads should be defined in advance.

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During the second step it has been figured out the renovation principles and how can be outer shell retrofitting be a good, easy and cheap solution to push the skyscraper towards a net zero building on the same line with the green regulations in Europe, see through two different groups of former case studies the first one describes a series of guides that analyze the sustainable principles and systems for new built skyscrapers which is responsible for reducing the energy equation, the second group collects some case studies that have been selected to cover a variety of climate and socio-economic regions to highlight the practical potential, opportunities and barriers of energy efficient high-rise refurbishment. Instead of tearing it down, it developed using remedial action – aesthetic as well as technical The projects featured here present a striking symbiosis of old and new.

In the last step before knowing how to measure building’s energy consumption, it might be helpful to know first the methodology of Building Performance Analysis. Applying this methodology on assessing for an existing building (Torre GALFA) will help to understand the effect of choosing each design solutions be done and compare it through a benchmark of energy standards like ASHRAE 90.1 and ARCH 2030. In particular in this step (Revit & Insight) as a BIM and energy assessment softwares will be used to assess the building energy performance. Firstly an energy consumption datum should be specified in order to compare with the consumption of different retrofitting design solutions. The point that has been chosen is the actual case of Torre GALFA which is under construction of a big retrofitting phase; this part contains a simulation for whole building energy, heating, cooling, and day lighting and solar radiation, also a study on Milan local climate. In order to choose the right parameters of installations and building envelope elements that optimize the energy needs and the indoor comfort, a high number of design strategies will be tested in order to define the best strategies to apply to Torre GALFA to optimize its energy performances.

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Index

Abstract

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Index

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Chapter 01 Environmental impacts of Skyscrapers energy consumption

1.1 Environmental Issues & Building Design

1.1.1Environmental Impacts of Building’s operation

1.1.2 Environmental impacts

through Construction & Design of Today’s Common Skyscraper

1.2 Minimizing environmental impacts through

design an eco-skyscraper

1.2.1 Retrofitting the façade for existing skyscraper

1.3 Are Skyscrapers more environmentally

friendly than smaller scale buildings?

1.3.1 What is the skyscraper?

1.3.2 The Skyscraper Building

Type and what differentiate it from common buildings

1.3.3 The Skyscrapers land use,

built form and plot ratio 1.3.4 Why skyscrapers?

1.3.5 Sky scrapers development

in Europe in the 20th and 21st centuries Summary

11 13 14 18 21 7

22 25 26 27 28 29 30 36

Chapter 02 Building energy loads and performance analysis

2.1 Building’s energy loads 2.1.1 Thermal loads

2.1.2 Heating and Cooling Loads

2.1.3 Equipment, lighting, and plug Loads

2.2 Building Energy Use measurement through Building Performance Analysis process

in different project phases

2.2.1 Energy Use Intensity (EUI)

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37 39 40 45 47 51 51

Chapter 03 Green retrofitting design goals

3.1 Design strategies behind green retrofitting

for High Performance buildings

3.2 Design Goals for high performance buildings 3.2.1 Thermal comfort 3.2.2 Visual Comfort 3.2.3 Acoustic Comfort 3.2.4 Air Quality

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Chapter 04 Green Retrofitting for Skyscrapers

4.1 Retrofit Drivers 4.1.1 Economics 4.1.2 Evironmental 4.1.3 Governmental

4.1.4 A New Trend

4.2 Common efficient key elements for green retrofitting of Skyscrapers facades 4.2.1 Service core 4.2.2 Building orientation

4.2.3 The façade treatment,

double skin and transitional spaces design options 4.2.4 Transitional spaces

4.2.5 Interactive external walls 4.2.6 Building’s plan configuration

87 90 90 92 93 95

58 63 64 72 78 82

96 97 98 102 106 109 109

4.2.7 Vegetation, solar shading,

cross ventilation as a passive

way to cool buildings

04.2.8 Thermal mass and thermal insulation walls

4.3 Case Studies of green retrofitted

Skyscrapers

4.3.1 Empire State Building,

New York, NY, USA

4.3.2 Willis Tower, Chicago, USA

4.3.3 Taipei 101, Taipei, Taiwan

4.3.4 Adobe System Headquar

ter Complex, San Jose, CA, USA

Summary Chapter 05 Building Performance Analysis

5.1 Project Phases & Level of Development 5.1.1 Project Phase

5.1.2 Level of Detail (LOD)

5.2 Drawing the BPA connection 5.2.1 Pre-Design 5.2.2 Conceptual Design 5.2.3 Design Development

5.2.4 Final Design and Docu mentation 5.2.5 Construction

5.2.6 Operations and Mainte nance

5.3 BPA Software Workflows

5.3.1 Knowing Goals and Metrics

5.3.2 Using Tools for Simulation & Analysis

5.3.3 Design Optimization Deci sions

5.4 Autodesk Insight Tools

5.4.1 Insight Energy Optimization 5.4.2 Insight Solar 5.4.3 Insight Lighting

5.4.4 Insight Heating and Cooling

112 117 118 118 125 127 128 129 131 135 135 135 138 138 139 141 142 143 144 145 146 146 146 148 148 149 149 149

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Chapter 06 Torre GALFA Green retrofitting

6.1 Pre-design phase 6.1.1 GALFA Refurbishment

6.1.2 Site analysis and local cli mate

6.1.3 Sustainable strategies appli cable 6.1.4 (EUI Baseline)

6.1.5 Torre GALFA Solar analysis

6.1.6 Torre GALFA daylighting analysis

6.1.7 Wind Pressure effects on

Torre GALFA external facade

6.1.8 Torre GALFA Heating/cooling loads

6.2 Design development phase

6.2.1 Refurbished GALFA Datum

6.2.2 Service core position 6.2.3 Facade orientation 6.2.4 Solar shading 6.2.5 Interactive facades

6.2.6 Vegetation for cooling and natural ventilation

151 156 156

Conclusion

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162 165 165 168 170 172 172 176 176 177 179 182 183 184

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Chapter 01 Environmental impacts of Skyscrapers energy consumption

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Fig:1.00 THE GLOBAL IMPACTS OF CLIMATE CHANGE (http://thebritishgeographer.weebly.com/the-impacts-of-climate-change1.html)

/01 Environmental impacts of Skyscrapers energy consumption

01.1 Environmental Issues & Building Design Climate change is a big issue happening which has effects that will have severe consequences for our society and environment. Reducing energy use in buildings is one of the most important ways to reduce humans’ overall environmental impact.

After all the modern environmental scientific reaserches, now we are sure that climate change is occurring as a result of human activity. Global climate change have linked to the increase in Greenhouse Gas Emissions (GHGs) done by human which leads to increase in global temperatures (especially in the past 250 years, since the industrial revolution). The use of fossil fuel-based energy is the primary source of this increase in GHGs. There is a lot of disturbances has been obsereved as a primary cause of climate change such as the loss of mountain glaciers and ice cover on the Earth’s Polar Regions, changes in the timing of the spring bud-break, and intensity of extreme weather events such as cold waves, heat waves, large storms, hurricanes and tornadoes, floods, and droughts,and an increase in the frequency.

Climate scientists have mentioned that human civilization is in danger of crossing a threshold that could lead to more intense changes in the global climate, and that could accelerate a new ice age or either a new “hotter and wetter” age similar to the Earth’s environment before the appearance of human beings. (Intergovernmental Panel on Climate Change, IPCC Fifth Assessment Report [AR5])¹.

According to some scientific estimates in the next 10 years there is an opportunity for reversing the impact of the climate change . After that, the global climate may change irreversibly, and humans will just have to adapt.

1 IPCC (2014), The Fifth Assessment Report of the United Nations Intergovernmental Panel on Climate Change Available at https://www.ipcc.ch/report/ar5/

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A real practical change should be implemented by the architects, engineers, and builders with the skills and resources that provide real, practical, cost-effective, and inspiring solutions for buildings.

01.1.1Environmental Impacts of Building’s operation Buildings account for 40% of worldwide energy use — which is much more than transportation. Furthermore, over the next 25 years, CO2 emissions from buildings are projected to grow faster than any other sector. The 164 million buildings in the EU-15 (193 million in EU-25) account for about 40% of final energy demand and about a third of greenhouse gas emissions, of which about two-thirds are attributed to residential and one-third to commercial buildings.² Often, energy use in the form of electricity drives the largest environmental impacts. Where that electricity comes from determines what those impacts are. In the United States for example, where buildings account for more than 70% of electricity use, most of the electricity is generated by coal-fired electrical power plants (USGBC).³ Generating one megawatt hour (MWh) of electricity in the US produces approximately 250 – 900 kg of CO2 depending on the mix of coal, nuclear, hydro and other sources of fuel (US EPA)4.

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Fig:1.01 Total building life cycle Buildings account for 40% of energy use worldwide (WBCSD).Energy used during its lifetime causes as much as 90% of environmental impacts from buildings (Journal of Green Building).Building operations consume more than 2/3 of all electricity (BuildingScience.com) 2 WBSCD, Manifesto for energy efficiency in buildings Available at https://www.wbcsd. org/contentwbc/download/2072/26118 3 Journal of green building, USING LIFE CYCLE ASSESSMENT METHODS TO GUIDE ARCHITECTURAL DECISION-MAKING FOR SUSTAINABLE PREFABRICATED MODULAR BUILDINGS Available at http://www.journalofgreenbuilding.com/doi/abs/10.3992/ jgb.7.3.151?code=copu-site

As a reference, the average US household consumes approximately 11 MWh of electricity per year (US EIA)5.

These exact impacts can be quantified by lifecycle assessment (LCA) (Fig:1.01), the most thorough way to determine the environmental impacts of a design. There is no perfect way to measure environmental impact. LCAs can measure greenhouse gas (units = CO2e = CO2 equivalent) to measure global warming potential, or might measure other things like human health, water, and land-use impacts. You may hear the word “embodied energy” or “embodied carbon” – this refers to the energy or greenhouse gas emissions caused throughout an object’s lifecycle. Alternatively, sometimes an overall normalized score is used to combine many kinds of impacts into a single number (i.e. Eco-Indicator 99).

A 2012 LCA study found that “Specifically within commercial buildings, the use and operation phase of the material and building life cycle is so dominant that the impacts of construction, demolition/disposal, and transportation are nearly irrelevant for most traditionally constructed buildings.” (Journal of Green Building). 3

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Fig:1.02 Total life cycle impacts by life cycle phase for a prefabricated commercial building with average California energy use, the building as built (30% of power supplied by photovoltaics), and net zero energy (100% of power supplied by photovoltaics), in units of EcoIndicator99 points. (EcoIndicator99 standards) 4 US EPA, Greenhouse Gas Inventory Guidance Available at https://www.epa.gov/sites/production/files/2016-03/documents/mobileemissions_3_2016.pdf 5 US EIA, Average Price of Electricity to Ultimate Customers by End-Use Sect Available at https://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=epmt_5_06_a

Since 1920, the overall trend in building energy use for commercial buildings is higher energy intensity per square meter.

It is important to reverse this trend. In the coming decades, rapid development will continue in the developing countries, while many buildings in the developed world will need to be renovated and retrofit. We need to make sure that the engineers and architects working on these buildings are equipped to make design choices that use energy effectively.

It has already been well argued elsewhere that designers should make our manmade environment ecologically sustainable or ‘green’ (e.g. WCED, 1987; Sitarz, q., 1994).6 Many are already well aware of the extensive degradation inflicted on the natural environment; for instance, the earth’s biodiversity is calculated to be degraded at the rate of 50,000 species per annum (Brown, 1991) 7 as a result of humanity’s callously destructive activities. With regard to the earth’s inorganic resources, it is also clear that the current relatively low-cost provision of energy to the built environment from non-renewable sources and the profligate use of irreplaceable materials can certainly not continue. It is projected that, at most, we might expect to have a sufficiency of biospheric non-renewable energy resources for perhaps another 50 years (Von Weizsacker, Lovins, A.B., and Lovins, L.H., 1997) 8. It is therefore evident that designing with ‘green’ or environmentally responsive design objectives in mind is vital. Indeed, these must certainly now be the prime objectives for the design community today.

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Fig:1.03 Built environment impacts on (source: The Green Skyscraper, Yeang, 1995)

its surroundings

6 WCED (1987), Report of the World Commission on Environment and Development Available at http://www.exteriores.gob.es/Portal/es/PoliticaExteriorCooperacion/Desarrollosostenible/Documents/Informe%20Brundtland%20(En%20ingl%C3%A9s).pdf 7 Whendee L. SilverSandra BrownAriel E. Lugo, Biodiversity and Biogeochemical Cycles Available at https://link.springer.com/chapter/10.1007/978-3-642-79755-2_4

It is evident that it is the early stages in the production of a building, especially at the design stage, that offer the greatest opportunities for addressing the anticipated problems of environmental impairment that may arise later in the building’s life cycle .

More than 40 percent of energy used in a country goes to buildings, and up to 26 percent of landfill waste comes from building construction. In this regard, the architect and designer of buildings can most certainly contribute significantly to a sustainable future. Important early design decisions start when the designer selects the raw and assembled materials to be used in the building, the type of operational systems for the building, and the routes to be taken to the final ‘sink’ for all the materials, parts and waste energy from the built system.

All these decisions will have a greater or lesser environmental impact depending on whether they are made as preventive decisions or as environmentally callous decisions. Of course, we have to recognize the fact that in environmental design there will certainly be no such thing as a perfect solution, nor will there be instant technological fixes that will solve the myriad of environmental issues associated with producing a building, particularly at the scale of a skyscraper. Neither is there hard and fast rules for all our design endeavours.

In green design, the environmental responsiveness of a particular design solution depends almost entirely upon the extent of the designer’s ability and ingenuity. This is simply because green design is a process in which the environmental attributes of a building are treated as objectives rather than as constraints (Goldbeck, The Office of Technology Assessment, U.S. Congress, 1995). Therefore, in most instances, a design’s success in fulfilling its ecological objectives depends much upon the creativeness of the designer and the inventiveness of the solutions he or she generates to address the limitations and opportunities presented by the site and in the design problem itself. Simply stated, the greater the adherence to the principles of applied ecology, and in particular, the greater will be the effectiveness of the environmental solution.

What is also distressing is that many of the sustainable designers today still prefer to deal primarily with small-scale buildings (i.e., with low-rise and medium-rise buildings) and often only in Greenfield and rural sites (e.g., Crosbie, M.J., _1994).9 All those large-scale and intensive building types 8 Doubling wealth–halving resource use Available at http://journals.sagepub.com/doi/ abs/10.1177/027046760002000505 9 Crosbie, M.J.(1994), Working in two worlds. Progressive architecture

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(such as skyscrapers) located in urban areas and in dense inner cities are regarded as anathema. Undoubtedly, intensive urban buildings are indeed energy guzzlers, consuming huge amounts of materials in their construction and making massive volumes of waste discharge into the environment.

This disparaging view of these building types is of course not disputed here, but surely these are precisely the reasons why such buildings demand our attention. For if all environmental designers refuse to confront the design of intensive large urban building, then who will? Furthermore it may be argued that it is these very high- density intensive buildings that should command by far the greater part of our expertise and effort with regard to creating environmentally healthy and responsible designs than the smaller buildings which present fewer problems.

01.1.2 Environmental impacts through Construction & Design of Today’s Common Skyscraper

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Since the early Twentieth Century Skyscrapers have been built in different corners of the planet, but no matter where, they more often than not have been built without any real concern or thought given to the environment that it is situated in, or the environment as a whole itself. At the time there was no need to think ecologically in design or construction of the skyscraper, the client simply wanted a design that would give them the most profit, maximum floor space to rent out, whilst the architects most important aim was perhaps creating an impressive feat of art with the design of the building, to make it eye catching to all around, a symbol of their work, something they could easily be recognized for.

Whilst it seems obvious from the outset that no one ‘set’ guideline for the design of the Skyscraper could be set, guidelines on components/technology, and strategies of design for the building could provide a positive impact into the design of each Skyscraper.

Raw materials play a key role in the construction of skyscraper as reinforced concrete in one of the main components of the building’s design. In more modern time it is more natural to see concrete and steel used together as it combines the two materials strengths to maximise the structural support it offers, whilst often taking less floor space to place, as the steel reinforcement sits in-situ in the concrete beam. Concrete is naturally very strong under compressive

forces, whilst steel is also inherently strong under the same forces (Hall, 2008)10.

Although steel is readily available, it takes a vast amount of energy to produce, and can often be an expensive business with the price of iron ore, a main component of steel, rapidly rising, it could easily become too expensive to use on such large scales in the future. Recently carbon fiber has often been incorporated into projects (for example airplanes) that would usually require steel and the attributes it brings – high strength, stiffness and lightweight – because it is a much cheaper alternate, it may not be long until the industry see’s carbon fiber taking more of a role in the construction of skyscrapers. Not only is the production of these materials highly energy consuming, they also require a large amount of toxic chemicals to make them attractive, fireproof and waterproof.

Large skyscrapers that are constructed with a mainly glass façade are in particular extremely high energy wasters, with heat loss (or gain) up to ten times greater through a typical 1 cm plate of glass compared to that of a typical masonry construction filled with insulation. (Popfun, 2009) It is not only the materials and construction of Skyscrapers that have a lasting impact on the environment; the actual every day running of the modern box skyscraper also has quite an impact. The typical 20th century box skyscraper was often designed with poor thermal performance and without the use of natural air ventilation systems the buildings are commonly too cold in the winter and too warm in the summer for people in the buildings to feel comfortable within so heating, ventilation and air conditioning (HVAC) units are regularly installed in the constructions. These HVAC systems require a vast amount of energy to run, as these services have to be pumped up and around the building through services ducts against the force of gravity, meaning the higher the skyscraper, the more energy it takes to operate these systems.

In the 1970’s it was believed that replacing the large all glass facades of the skyscraper with smaller, sealed windows would reduce energy consumption caused by heating the structures because it would stop the loss of heat and air conditioning to the outdoor world, this however resulted in poorly ventilated buildings which resulted in a higher demand on the air conditioning units to run the services at the correct level to provide a comfortable internal environment. (Gissen, 2003) However the effects and impacts of the air conditioning units often installed in skyscrapers are well documented and sometimes they can make the internal conditions worse instead of 10 Nawy, Edward G. (Prentice Hall,2008) Reinforced Concrete 6th Edition 11 D. Gissen (2003), Big and Green: Toward Sustainable Architecture in the 21st Century

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improving them. Sick building syndrome is usually accredited to air conditioning units (as well as other heating and ventilation systems), the lack of oxygen, and high levels of carbon dioxide and carbon monoxide are generally believed to be the main cause. (Habmigren, 2003) If a building does develop sick building syndrome than occupants will often fall ill, with varying symptoms ranging from irritation of the eyes, nose, throat to general health problems and skin irritation.

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Another problem caused by the design of skyscrapers, all though less of an environmental issue at first glance, can have knock on effects on the environment. “Towers are always fighting against their own weight. As more parts of the building are devoted to holding it up, they encroach on the space for working or living in. Developers and leasing agents refer to the ratio between these two elements as a building’s “net-to-gross”. In a really efficient skyscraper, nearly 70% of the building’s volume is useable, with the rest taken up by liftshafts, stairwells and pillars. In a well-designed low-rise building, by contrast, more than 80% of the space can be sold or let.” (Economist, 2006) With these companies moving out of the city to office complexes for financial issues, it is leaving an increasing amount of unused office space in these skyscrapers, whilst more new skyscrapers are being built. 40% of the world’s tallest buildings have been built since the year 2000 (Economist, 2006) but many skyscrapers have been left with empty office space, simply because of the cost of running the building or because of an outdated look.

Many of the problems to the environment caused by the Skyscraper typology are caused by designing to maximize the economic benefits of the building, increasing rent per square meter of floor space, instead of being designed with the environment in mind.

To understand the potential environmental benefits from contemporary design, the ways skyscrapers may be harmful must be considered. With Otis’ development of the safety brake in 1854, the elevator age began. Early skyscrapers were dominated by desire to reach new heights, rather than any environmental concern, ensuring that high-rise buildings now consume 16% of energy worldwide. When compounded by increased exterior exposure to wind and sun, poor insulation of early skyscrapers results in higher heat gain and loss, ensuring that they need constant heating in colder months and cooling during summer. Heating, ventilation and air conditioning account for an estimated 75%+ of energy consumed by high-rise buildings, with 30-50% of transmis-

+

=75%

30-50% of energy losses through

sion losses through windows, even though their contribution to the overall surface area is much less. With rising energy costs and awareness of the finite nature of resources, insulation problems allow anti-skyscraper advocates to tarnish tall buildings as environmentally harmful. However, as Appel recognises, ‘you take the same amount of energy to heat a space and cool a space whether it’s 900 feet up in the air or ten feet up in the air’. Thus, insulation problems are not limited to skyscrapers. Moreover, due to their height, skyscrapers entail intrinsic design features which can harm the environment, as more energy is needed to provide electricity and water to upper floors, and to allowing occupants to access higher floors.

As buildings become taller, elevators become faster and bigger, increasing energy consumption. However, elevator energy use is recognised, and contemporary innovations can now minimise their consumption to as little as 5% of energy consumed by the whole building. Consequently, sustainable design offers potential to mitigate the environmental impact of skyscrapers.

01.2 Minimizing environmental impacts through design an eco-skyscraper

Fig:1.04 Bahrain

World Trade Center wind blades (source: http://www.traveladventures. org)

Other contemporary design allows skyscrapers to have minimum negative environmental externalities. Green design and clean technology solutions have led to ‘eco skyscrapers’. For example, the needle-shaped Okhta tower, St. Petersburg, allows sunlight to penetrate the building, using natural light to ensure comfortable temperatures without needing artificial heating. Additionally, skyscrapers need not only consume energy. For example, Bahrain’s World Trade Center holds three 96foot wide wind turbine blades between the towers, producing 1300 MWh per year. The proposed Lighthouse Tower in Dubai will feature 4000 south-facing solar panels and three 225 kilowatt wind turbines, reducing energy needs of the building by 65%.12 However, these new designs have been questioned.

For example, 30 St. Mary Axe ‘The Gherkin’, is portrayed as ‘London’s first environmental skyscraper’ as its shape maximises natural lighting, reducing need for artificial light.

However, its glass façade is accused of creating intense light glare, raising surrounding air temperature and affecting neighboring buildings. Concentrating on constructing green skyscrapers ignores how they affect other buildings. For example, skyscrapers can shade nearby buildings, thereby increasing their need for artificial light and reducing their potential solar en12 The Butler Scholarly Journal (2015) The Value of Verticality: Why assessing the environmental impact of skyscrapers needs to look beyond building design

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ergy generation. Consequently, blanket claims for the sustainability of innovative design features are inappropriate, implying that there may be value in considering the other ways in which skyscrapers relate to the environment.

01.2.1 Retrofitting the façade for existing skyscraper

Fig:1.05 Apportionment of costs for a typical skyscraper (source: Hira, A, Paks, M, ’Design and Construction of cores of tall buildings- Achieving TQM through multi-disciplinary approach’ 1994)

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Furthermore, new constructions fail to consider feasibility. In dense cities, the practical capacity to construct new eco-towers is limited by ever-reducing amounts of land. New eco-scrapers would ensure high-performance developments, whilst allowing inefficient buildings to continue to pollute the environment.

Not surprisingly, one of the major reasons for building owners to renovate their buildings is the concern for environmental issues.

Global warming is no longer just estimation but an undeniable challenge humans are facing. However, building owners may not dare to go green because of financial concerns. To solve the problem, some utility companies, national, state or county, have initiated financial assistance programs for owners to carry out energy efficiency retrofits for their buildings. Countries like Czech Republics, Canada, U.S., etc. give funding, incentives or tax credits for property owners who do extensive renovations on their buildings. One of the programs in the States, called the Energy Policy Act, gives incentives to residential and commercial building owners who conduct renovations for energy efficiency and sustainability.

In 2010, U.S. Vice President, Joe Biden announced the provision of $425 million funding to speed up the energy efficien-

cy building retrofits in the country. Biden also commented on building energy efficient renovation as “a triple win.” One win is for the environment due to reduced energy usage, which will significantly lower the greenhouse gas emission annually.

Another win is for the energy consumers whose energy bill will be reduced by the retrofit. The last win is for the economy as green jobs will be created 13.

Fig:1.06 Reasons for retrofit (Source: Commercial and Institutional Building Energy Use Survey 2000 (CIBEUS) Summary Report, December 2003)

Consequently, creating more energy efficient cities may benefit from retrofitting existing skyscrapers. Firstly, skyscrapers can be retrofitted with on-site renewable energy generation. For example, in 2005, Manchester’s CIS Tower was retrofitted with 7,000 solar panels and 24 wind turbines, allowing the tower to supply 10% of its energy needs. Secondly, responding to concerns about poorly insulated skyscrapers, retrofitting can reduce energy consumption needed for heating and cooling.

This includes small-scale, incremental adjustments, such as replacing single-pane windows with double-panes and weather stripping windows to seal the interior from heat escape. In 2009, all 6,514 windows of the Empire State Building were refurbished (will be explained briefly in chapter 05), insulation was installed behind radiators and a low emissivity film and gas mixture was placed between the re-used panes, reducing energy use by 38%. Third, elevators can be retrofitted to reduce energy use. Continuing with the Empire State Building, all 68 elevators became 30% more efficient by reducing the 13 Dwyer, Devin (2010). “Biden Announces Funds for Energy Retrofitting Projects on Earth Day Eve - ABC News.” ABCNEWS.go.com. ABCNEWS.go.com.

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waste heat of machinery and channeling waste energy back into the electrical system. Retrofitting existing skyscrapers is promising given the quantity of existing stock. Indeed, it is proposed that it would take 10-80 years for a building 30% more efficient than an average-performing building to overcome the environmental impact of construction, implying that it is more beneficial to revisit existing buildings than to construct eco-skyscrapers.

Fig:1.07 CIS Tower (Manchester,UK) and Empire tower (New York, USA) (source: solaripedia.com) 26

state

Considering technical adjustments ignores how users respond to energy-saving features. Constructing, or adjusting existing buildings to be environmentally-friendly alone is insufficient if those interacting with the building doing not adopt an environmentally-friendly mindset. Indeed, it is claimed that in large residential or office complexes, user behavior and its consequences are often disconnected. This is because those using energy do not pay for what they use, so have no financial incentive to reduce energy use. Thus, if climate change is anthropogenic, assessment of the environmental impact of building design is incomplete without considering the human use of these features. Sustainable design will not inevitably trickle-down to occupants; there is need to create environmental awareness at the point of use. To understand the environmental impact of buildings, planners need to move beyond the mid-20th century modernist approach to urban design to thoroughly consider how buildings are engaged.12

01.3 Are Skyscrapers more environmentally friendly than smaller scale buildings?

Alternatively, skyscrapers may be beneficial in the compactness they enable. Firstly, skyscrapers increase urban density. Glaeser proposes that cities should build upwards in already dense areas to reduce the need to build outwards. Glaeser claims that ‘living in a concrete jungle is actually far more environmentally friendly’. Documenting a carbon inventory of housing in America, he claims that ‘the average household living in a census tract with more than ten thousand people per square mile uses 687 gallons of gas per year, while the average household in an area with fewer than one thousand people per square mile uses 1,164 gallons of gas per year’. Even if cities produce a large proportion of national carbon emissions, reduced commuting levels suggests that living in cities may be greener than living in ‘green’ suburbs. Secondly, compactness means that journeys can be combined. ‘Lunch hours and journeys to and from work can be used for errands, such as shopping… so people maximise the efficiencies of their journeys’, rather than making repeat trips. This demonstrates that building on a concentrated scale not only removes the need for daily commutes from suburbs but offers possibility to reduce intra-urban travel by situating workplaces near utilities. Further, compact cities allow space to be preserved elsewhere, so that surrounding natural areas can continue to provide habitats for plants and animals and remain as protected environmental areas. Not only does preserving open space reduce potential competition from developers, open space also protects water resources by filtering pollutants and debris from entering the water system. Therefore, considering the skyscraper at the scale of the building itself naïvely overlooks how skyscrapers relate to the wider urban geography 14

Fig:1.08 São Paulo, Brazil In a recent study, most urban areas were found to have smaller carbon footprints than their national averages. (source: the comparatively green urban jungle NY times) 14 A. Ensha (2009). “The Comparatively Green Urban Jungle” Available at (https://green. blogs.nytimes.com/2009/04/01/the-comparatively-green-urban-jungle/)

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In the context of increasing urbanisation in the global south, predictions that global carbon consumption will increase by 139% if the average person in India and China created the same carbon emissions as the average American, imply that reducing carbon emissions in daily activity is essential.

Growth is predicted to be concentrated in cities, with urban areas set to expand by over 1.2 million km² between 20122030. It is vital to determine how energy use can be reduced in cities. As such, determining the environmental impact of urban infrastructure is of great urgency to mitigate human impact. Urban areas, by condensing lifestyles and reducing the need to commute, have great potential to reduce energy use. Fortunately, urban planners have begun to recognise that merely building green is insufficient, as ‘a very green tower that’s car-orientated isn’t really green’. By reflecting on infrastructure, policymakers have a prime opportunity to ensure that rapid urbanisation need not guarantee environmental harm. In doing so, considering the environmental prospect of tall buildings must shift from narrow considerations of small-scale design features to how skyscrapers interact with the wider urban space.

In order to find a methodology that works to have less environmental negative impacts because of skyscrapers through retrofitting the facade, we have first to define what is skyscrapers?, what the difference between skyscrapers and regular building?, what is the skyscraper’s location?, and the skyscraper façade retrofitting design aspects?.

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01.3.1 What is the skyscraper?

The term “Skyscraper” Around 1890, the term ‘skyscraper ‘ was coined to describe ‘ the multi-story office building type which was being built predominantly in the central areas of Chicago and New York in the USA. By 1884, ‘skyscraper’ was being used as an adjective to describe tall buildings; its first use as a noun occurred around 1889. As late as 1933, the Oxford English Dictionary still provided six different definitions of the word ‘skyscraper’, which included one for a high-standing horse and another for a very tall man! Finally, by the advent of World War I, the term had become sufficiently common place to refer primarily to the tall building type.

Since the beginning of human organization the height of build-

ings has been limited to a person’s ability to climb stairs. For centuries, buildings reached their commercially optimum height at about four to five stories.

The Council on Tall Buildings and urban Habitat (CTBUH) initially considered tall buildings as being of ten stories or over because that had been the cut-off height for fire-fighting from ladders in New York City. Although today’s fire-engine ladder can reach higher than ten stories, this broad criterion remains.15 Another definition is in the ASHRAE (American Society of Heating, Refrigeration and Air-conditioning Engineers) Handbook of Fundamentals (1989) which categorizes a high-rise building as one in which its height (H) is more than three times its crosswind width (W).

Recently, the CTBUH (L Beedle) wrote: ‘a multi-story building is not defined by its height or number of floors. The important criterion is whether or not the design is influenced by some aspect of ‘tallness’. It is a building whose height creates different conditions in the design, construction, and operation from those that exist in ‘common’ buildings of a certain region and period.’

01.3.2 The Skyscraper Building Type and what differentiate it from common buildings Technologically, the skyscraper is the culmination of a number of building inventions, such as the structural-frame with wind-bracing, new methods of making piling and foundations, high-speed elevators , air-conditioning systems , flush-toilets, large pieces of glazing and window-framing, advanced telecommunications and electronics, advanced indoor-lighting , ventilation, and cleaning technologies. But we will focus on this study about the façade elements and how it can be possible to change the environmental impact of the skyscraper through changing the building’s energy consumption using façade retrofitting techniques.

Spatially, a skyscraper can be regarded (especially by the commercially-minded developer) as being simply an intensification of large areas of built space concentrated over comparatively small parcels of land area (or over small building footprints). The skyscraper enables more usable floor-space to be placed over a small plot of land by simply going higher. It allows more cash to be made from the land, with more goods, more 15 CTBUH. “CTBUH Height Criteria for Measuring & Defining Tall Buildings” Available at (http://www.ctbuh.org/LinkClick.aspx?fileticket=zvoB1S4nMug=)

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people and more rents derived from one place.

Consequently, because of its evident commercial objectives, the goal of the developer is obviously to achieve high structural efficiency with minimum premium-for-height. Very often (and unfortunately so) what happens is that the executive managers of the developer determine the building’s typical floor-plate and, having devised the workspaces, leave the architects the role of simply designing the building’s outside envelope. Special attention needs to be focused on the environmental design of the skyscraper building type more than on other intensive urban buildings (mostly medium-rise or low-rise),16 The skyscraper’s construction is motivated essentially by high land prices and urban transportation expediency. Economically, to enable its developer to get the optimum financial returns from the high urban land prices, the skyscraper has to have sufficient gross floor area (the total built-up space consisting of floors stacked one on top of another) to spread the high land value over the total net floor area (its net rentable or saleable space).

01.3.3 The Skyscrapers land use, built form and plot ratio

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In Fig. 1.09, it is clear that for a site with plot ratio of 1:4 and with a 60 percent building footprint (i.e. site ground-plane coverage), the resultant built form is already six stories high, and this

Fig:1.09 Land use, built form and plot ratio (source: The Green Skyscaper, Yeang, 1999, page 26) 16 Ken Yeang (1999), The green skyscraper: the basis for designing sustainable intensive buildings, page 26.

is excluding parking provision above ground. If full car-parking space is to be provided above ground, then the building is likely to be ten stories or more. Therefore, it is evident that there is no other alternative with such small sites but to go upwards in the form of a tower.

Another aspect of the skyscraper’s built form is that it has extensive vertical surface areas, which affects the extent of solar penetration or build-up into the interior. Formal studies show that it is the circular-plan built form that has the least surface exposure. 16 01.3.4 Why skyscrapers?

The contention is simply that the issue of the environmental design of large buildings (whether we like these buildings or not) is just as vital as the environmental design of the smaller building types - in fact more crucial, because of their scale and volume of consumption of energy and materials.

As a result of these trends, the building of intensive urban developments of all types will most surely continue. Skyscrapers, though hateful they may be to some, will continue to be built as long as land prices continue to go up and entrepreneurs conclude that the only way to recoup the high cost of urban land is to increase plot ratios- i.e to build upwards and more intensively on a given piece of land. This is unfortunately the reality of the day, an inescapable fact of the economics of urban land economy.

On the other hand, some might be tempted to claim on the basis of these same facts that skyscrapers are indeed the preferred green building form over the low-rise precisely because they have a smaller footprint, and the residual portion of the land (because of the lower land coverage) can be returned to nature.

Therefore, it is held here that the skyscraper and similar intensive building types need immediate and urgent attention from the world’s ecological designers to make sure that these are built to be ecologically responsive or at least as environmentally responsive as possible for our sustainable future. 17

17 Ken Yeang (1999), The green skyscraper: the basis for designing sustainable intensive buildings, page 11

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01.3.5 Sky scrapers development in Europe in the 20th and 21st centuries Europe cities with their dense historic fabrics greeted skyscrapers with a great deal of scepticism. It was not until the 1950s that Europe began to construct buildings taller than 100 meters. By 2013, skyscrapers had been constructed in over 100 European cities located in 30 different countries, and the trend towards the expansion of high-rise construction continues. Although Europe is currently constructing its first two super tall skyscrapers, European buildings generally do not exceed 250 meters. Today, the majority of European skyscrapers are office buildings; although in the 21st century there has been an increasingly significant tendency to equalize the quantity of residential and office buildings.

Moreover, the highest European skyscrapers are designed as mixed-use buildings. Significant development continues in leading centers of high-rise office construction located in the area between the United Kingdom and Italy, in Spain, and in Central and Eastern Europe. The majority of European office towers have been built in capitals. The key centers in the ongoing office skyscrapers’ development remain: Paris, Frankfurt and London.18

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Skyscrapers were first introduced in American cities characterized by a lack of historic buildings or historic urban fabric.

Europe, while certainly not afraid of building tall structures, accepted the American skyscraper typology with a great deal of scepticism. Developing high-rise buildings in European cities with historically evolved urban fabrics called for different and diversified approaches to high-rise planning - especially where these cities identities had begun to be linked to their historic structure.19 Prior to 1950 the United States had already completed over 200 skyscrapers in excess of 100 meters, and a few over the 250 meters limit. In the early twentieth century, the objects of historical value already became symbols of the European culture therefore; no new elements for their identification were needed. Moreover, due to a belief that high-rise structures might dominate the image of cities in a negative way, high-rise buildings in Europe were isolated phenomena well below the 100 meters limit.20

18 Joanna Pietrzak (2013), Development of high-rise buildings in Europein the 20th and 21st centuries, page 31.

19 Eisele J. and E. Kloft, High-rise Manual: Topology and and Design, Construction and Technology. Basel, Boston, Berlin: Birk - heauser, 2002.

20 CTBUH Tall Building Database | The Skyscraper Center [webpage] http://skyscrapercenter.com/. [Accessed on 25 May.2013].

It was not until the 1950s that Europe began to develop buildings over 100 meters. When work began on reconstructing destroyed towns and cities the rapid development of high-rise buildings resulted from the expanded demand for office and residential space, as well as the search for new, modern urban models. Some of the heavily damaged cities had no choice but to rebuild carefully integrating old and new. Though the prime aim of many realizations was to use the land as profitably as possible, skyscrapers began to symbolize the power administrative or economic of the towns where they were erected.

The following analyzed data related to: building’s height and function, the date and venue of its construction.

The presented analyses focused on the time span from 1940 (i.e. marking the construction of the first building higher than 100 meters) to 2013 and including the predictions for the years 2013-2018, compiled on the basis of data of being under construction and proposed buildings. Due to the locations of buildings with a height of over 100 meters, the analyses included 556 buildings constructed in or designed for more than 100 cities of 30 European countries (i.e. Austria, Belarus, Belgium, Bosnia and Herzegovina, Bulgaria, Czech Republic, Denmark, Estonia, France, Germany, Greece, Italy, Latvia, Lithuania, Luxembourg, Monaco, Netherlands, Norway, Poland, Portugal, Romania, Russian Federation, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Ukraine, United Kingdom).

The development research of the high-rise buildings in Europe was analyzed overall development of the skyscraper compared with regard to the decades, functionality and also includes the locations of high-rise and mixed-use buildings, including the division into buildings constructed in the twentieth century, in the twenty-first century, and those being under construction. tally responsive as possible for our sustainable future.

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Fig:1.10 Projection

of European cities with buildings over 100 meters in height by

2018 Note.

(The work based on data from The CTBUH Tall Building Database – The Skyscraper Center, retrieved on 25.05.2013 from http://skyscrapercenter.com)

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Fig:1.11 Projection

of European cities with buildings over 100 meters in height by 2018 Note completed each decade with the individual building hight (The work based on data from The CTBUH Tall Building Database – The Skyscraper Center, retrieved on 28.12.2017 from http://skyscrapercenter.com)

Fig:1.12 Projection of European buildings over 100 meters in function by 2018. (The work based on data from The CTBUH Tall Building Database – The Skyscraper Center, retrieved on 28.12.2017 from http://skyscrapercenter.com)

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Fig:1.13 European

high-rise buildings, 100 meters or taller, completed each decade and under construction: by function Note. (The work based on data from The CTBUH Tall Building Database – The Skyscraper Center, retrieved on 25.05.2013 from http://skyscrapercenter.com)

The European scale of high-rise buildings in relation to the global skyscrapers’ heights is limited. The erected European buildings, with the exception of the Russian projects, generally do not exceed 250 meters. Despite the skepticism which accompanied the introduction of high-rise buildings in Europe as well as some recent negative opinions on the erecting skyscrapers in the European cities, this type of buildings is more and more popular on the continent. To sum up the three main periods of the high-rise buildings growth (the turn of the 60s and 70s of the twentieth century, the 90s of the twentieth century and the twenty-first century), one can notice that the number of skyscrapers being built gradually increased, as well as their height and the number of cities in which the tall buildings are erected. The analyses presented above allow for a better understanding of the functional, which completed in each decade and the height structure of the European high-rise buildings note to the decade. This analysis aim is to help to choose between different skyscrapers which need to be sustainable redesigned through the technology of retrofitting their facades so they can meet the new international energy standards which will be elaborated later.

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The results is the skyscrapers which built in the twentieth century and functions as office building are the priority to study for different reasons; basically they are old and for sure they need individually to be tested for how much did the exceeds the energy standards limits. The reason of choosing office buildings is they are energy guzzlers more than other common uses built in the same time, and small change in the design through sustainability will have great a great impact on the environment.

Summary The sustainable retrofit for the skyscraper and other large buildings as the high-energy and materials-intensive urban building types of cities today is a matter deserving urgent attention from our sustainable designers. This development is vital because of the skyscraper’s iniquitousness worldwide.

Looking forward to our discussion of green design, we might redefine the skyscraper and other intensive building types from the viewpoint of the ecologist as being simply a high volume of inorganic mass that is brought together by the designer, then assembled and concentrated onto a small footprint site, and which operationally consumes large amounts of non-renewable energy resources, emits large amounts of wastes (mostly paper products and waste heat) and affects disproportionately the energy flows of the natural ecosystems of the locality.

At the same time, its users ( being only one of the multitude of biotic components in this inorganic mass) consume further amounts of non-renewable energy resources in coming to and departing from the building by various means, usually travelling over impervious road surfaces that detrimentally reduce rainfall infiltration back into the groundwater.

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Chapter 02 Building energy loads and performance analysis

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Fig:1.00 TYPICAL ELECTRICAL CONSUMPTION PATTERN IN BUILDINGS (Source: Thoughtful cooling workshop, Availabale at http://slideplayer.com/slide/10061176/)

/02 Building energy loads and Building performance analysis design workflows

Overview on Energy loads and performance analysis After defining skyscrapers and how they are energy guzzlers which affecting directly the environment and human health, also didn’t meet the EU environmental standards, it should be a way to define when green retrofitting is the optimal solution towards net zero buildings, and how to define, measure and asses retrofitting design goals needed before starting retrofitting design?

This chapter is an explanation of how buildings use energy, so the retrofitting designer can measure the building’s operation costs and energy demands before starting his works so he can compare before and after each step of his design and how it will affect the building’s performance, also how he can use a building performance analysis tools/software to show the skyscraper’s owner/investor the range of reduced energy demand and annual cost for his building so he can decide if façade retrofitting is the optimal solution for his investment?, but for the designer he has to be clear about his design goals behind green retrofitting to have a high performance skyscraper.

02.1 Building’s energy loads How can understanding the thermal loads improve sustainable design and dictate what can be done to decrease the building’s energy demands?

First of all we should understand internal and external thermal loads, heating and cooling loads, and how all of this translates to energy use intensity as a benchmark can used to compare energy demands between different buildings or between two design solutions for the same building.

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Knowing how to make sense of heating and cooling load information will help to choose the best building constructions and equipment to save the most energy.

Energy loads are how much energy your building needs.

These demands can be provided by electricity, fuel, or by passive means. Understanding building loads can be a complex topic because there are so many interrelated terms to navigate.

In a commercial building the average energy demands can be breakdown to 3 categories (HVAC, Lighting, Equipment & others).1 If the designer can generate enough energy on-site to be equal to the buildings’ annual energy needs, he will got a net zero energy building. To achieve net zero cost affectively, we need to reduce energy demand as much as we can, with passive design strategies the designer use the energy that’s already around, like the sun’s heat and light, If the passive strategies used well enough, a lot of money will be saved by downsizing or even eliminating the need for big heating, air conditioning, and lighting equipment. And when this equipment is needed, smart designs can make it ultra-efficient.

The infographic in the next page can help to navigate these terms and make better sense of building performance analysis results.

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02.1.1 Thermal loads They are the quantities of heating and cooling energy that must be added or removed from the building to keep people comfortable. Thermal loads come from heat transfer from within the building during its operation (internal, or core loads) and between the building and the external environment (external, envelope, or fabric loads).

These thermal loads can be translated to heating loads (when the building is too cold) and cooling loads (when the building is too hot). These heating and cooling loads aren’t just about temperature (sensible heat), they also include moisture control (latent heat). (See Infiltration & Moisture Control) Heating and cooling loads are met by the building’s HVAC system, which uses energy to add or remove heat and condition the space. This energy use translates to the 1 Understanding Electricity Demand Charges | Energy watch [webpage] https://energywatch-inc.com/electricity-demand-charges/. [Accessed on 02 July.2018].

Fig:2.01 Building’s

average

energy use Source: (cibse journal, Lighting control technologies and strategies to cut energy consumption )

Fig:2.02 Inforgraphic describe the relation between building’s energy use and thermal loads (source: Autodesk Building Performance Analysis and sustainability workshop, Building energy loads, sustainabilityworkshop.autodesk.com)

HVAC component of a building’s equipment loads (met by fuel or electricity). Other building loads include plug loads (electricity used for computers and appliances) and lighting loads (electricity used for lights).2 High performance buildings seek to reduce these loads as much as possible, and meet these loads as efficiently as possible.

By understanding the building’s thermal loads and its intended use, the designer can more effectively use energy from the sun and the wind to passively heat, cool and ventilate your building, light your building, and design efficient HVAC systems. You can even generate energy on-site using resources that would otherwise be thermal loads that would demand energy.

2 Building Energy Loads | Sustainable Building... at Autodesk Sustainable Building Design [webpage] https://knowledge.autodesk.com/search-result/caas/simplecontent/content/ building-energy-loads.html. [Accessed on 24 November 2017].

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Fig:2.03 The

building program determines whether internal or external loads dominate (source: Autodesk Building Performance Analysis and sustainability workshop, Thermal Loads, sustainabilityworkshop.autodesk.com)

02.1.1.1 External Thermal loads External thermal loads come from heat transfer through the building envelope from the sun, the earth, and the outside environment (and weather). The building envelope includes walls, roofs, floors, windows, and any other surfaces that separate inside and outside. They are sometimes also called envelope loads, fabric loads, skin loads, or external gains/ losses.

These loads include the energy embedded in the moisture of the air (see sensible vs. latent heat).

Some common ways that heat flows into or out of a building are: 44

• Heat conduction entering or leaving the building envelope to outside air or ground • Sunlight (radiant energy) entering through windows to heat interiors or store energy in thermal mass (direct solar gains) • Sunlight warming up exterior building surfaces (“indirect solar gains”) • Losing inside air to the outside, or vice-versa, through leaks and infiltration • Air being intentionally introduced to the building to provide fresh air/ventilation or being exhausted from point sources.3 Material choices, envelope design, and envelope sealing dramatically affect the amount of solar conducted and convected energy that enters and leaves the building envelope.

The degree to which each of this impact the building’s loads 3 External thermal loads | Autodesk Building Performance Analysis and sustainability workshop [webpage] sustainabilityworkshop.autodesk.com. [Accessed on 24 November 2017].

and the occupant’s comfort also depend on the temperature and humidity differences between indoors and outdoors, which are all constantly changing by season and time of day.

Understanding where heat energy is gained and lost in net zero design is an important first step towards successful passive design strategies. When it’s hot and sunny, it can be very important to reduce loads from solar radiation by using properly designed shades and windows with low solar heat gain. On the other hand, in a cold climate or in the winter, it’s often desirable to capture this free solar energy in some way.

02.1.1.2 Internal Thermal loads Internal thermal loads come from heat generated by people, lighting, and equipment. These are also sometimes called core loads or internal gains. Lighting and most equipment loads are sensible heat, while the metabolic heat generated by people bodies is a combination of sensible and latent loads. Some buildings or spaces are dominated by less common internal sources of sensible and latent internal loads such as large kitchens, swimming pools and locker rooms and health clubs or industrial processes.

The internal gains from lighting and equipment are generally equal to their energy use: when a light fixture converts a watt-hour of electricity into photons, those photons bounce around the room until they get absorbed, turning their light energy into heat energy.

Likewise, all the electrical energy that the lighting fixture did not turn into photons turns directly into heat energy, due to inefficiency.

The same is true of equipment: electrical energy used to move mechanical parts is transformed into heat via friction, energy used to power electronics turns into heat via electrical resistance, etc.

The thermal load of people depends on the number of people and their activity level. It can be as little as 70-80 watts for an adult sleeping to over 1,000 watts for an athlete engaging in intense exercise.4

4 Internal thermal loads | Autodesk Building Performance Analysis and sustainability workshop [webpage] sustainabilityworkshop.autodesk.com. [Accessed on 24 November 2017].

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Fig:2.04 Thermal loads from people doing different activities (source: Autodesk Building Performance Analysis and sustainability workshop, Thermal Loads, sustainabilityworkshop.autodesk.com)

02.1.1.3 Internal vs. External Loads Densely populated buildings with high activity and/or energy-intensive equipment (e.g. office buildings, movie theaters) are generally dominated by internal loads, while sparsely populated buildings with little activity or equipment (e.g. single family residences, warehouses) are generally dominated by external loads.

The building program and massing also help determine how important internal heat loads are compared to external loads from sun, wind, and ambient temperatures.

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Fig:2.05 When

interpreting energy load charts, pay attention to whether the biggest heat losses and gains come from internal or external loads (source: Autodesk Building Performance Analysis and sustainability workshop, Thermal Loads, sustainabilityworkshop.autodesk.com)

02.1.2 Heating and Cooling Loads Internal and external thermal loads translate to heating and cooling loads. This is how much heat energy you need to heat and cool the building, and control moisture within the building.

Loads are usually calculated as the amount of energy that needs to be moved into or out of the building to keep the temperature at a specified point (setpoint). • If heat gains are greater than envelope and ventilation losses, the building or space has a net cooling load (the building is too hot). • If heat losses are greater than the internal gains, the building or space has a net heating load (the building is too cold). • The heating thermostat setpoint is often different than the cooling thermostat setpoint both to save energy and because of human preference. The distribution of heating and cooling loads is climate dependent. 5 The heating and cooling loads below provide a break-down for what drives the heating and cooling energy demand.

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Fig:2.06 Monthly

heating and cooling load charts tell you where heat energy is being gained and lost (source: Autodesk Building Performance Analysis and sustainability workshop, heating and cooling Loads, sustainabilityworkshop.autodesk.com) 5 Heating and cooling loads | Autodesk Building Performance Analysis and sustainability workshop [webpage] sustainabilityworkshop.autodesk.com. [Accessed on 24 November 2017].

The PEAK heating and cooling loads are used by engineers to size HVAC equipment. These energy analysis graphs are meant to help understand energy flows, not size equipment.

However, using energy analysis tools can allow the designer to better understand and calculate energy use so that you can avoid oversizing equipment and look past the typical “rules of thumb.�

Using Energy to Meet Heating and Cooling Loads The values in the heating and cooling load charts above represent the amount of heating or cooling required, not the amount of energy a HVAC system would actually consume to generate the required load.

Passive systems reduce the energy demand or meet it naturally. Active systems move heat and moisture using gas or electricity. How much and what type of fuel the HVAC system will consume depends on the system type and efficiency.

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When using active systems, it usually takes more energy to meet heating loads than it does to meet cooling loads.

Heating systems based on combustion of a fuel are approximately 75%-95% efficient at converting the chemical energy in the fuel to heat delivered to the building. The efficiency of cooling systems (and heat pumps in heating mode) is not measured in percent efficiency because they do not convert potential energy to delivered heat, rather they use energy, most commonly electricity, to move heat either into or out of a building. The Whole Building Design Guide provides ranges of efficiency values and sizes that are typical for various types of cooling systems. Heat pumps and air conditioners use energy to move heat, they do not generate coolth. The cooling effect that we feel is the removal of heat rather than the addition of coolth.

Also, when you put cost into the equation it brings another level of complexity because heating fuel is much cheaper per unit of energy than electricity. Building owners often spend more on energy to cool their building than to heat their building. There are many reasons for this, but the easiest to understand is that electricity typically costs three to five times more than heating fuel per unit of energy.

02.1.3 Equipment, lighting, and plug Loads Lighting, HVAC equipment, water heaters, and appliances all consume energy in the form of either electricity or fuel. All of these things are important to understand and optimize for high performance building design, and are important inputs for whole building energy analysis simulation.

The equipment, lighting, and plug loads described below are determined by the building’s intended use, its occupancy, and its scheduling. In short: its program.

Building Program and Schedule A building’s program scopes the project by outlining its goals, conditions, and objectives. The program is usually defined by the owner, but it is important to also involve occupants and designers to create it.

The program explains how the design will be used by specifying things like activities, occupancy, and schedule of operations. It also includes more detailed requirements such as: room sizes, space needed per person, relationship between spaces, equipment needed, and budget, all these considerations affect the building’s energy use.

Types of Programs Some building programs are much more energy-intensive than others, and have different site considerations. For instance, in the US, educational buildings are relatively low energy intensity (averaging, 26 kWh/m2/yr) and are dominated by heating loads and lighting loads, while food service buildings are the most energy intensive (averaging, 81 kWh/m2/yr) and are dominated by equipment loads. 6

6 Building Program and Schedule| Autodesk Building Performance Analysis and sustainability workshop [webpage] sustainabilityworkshop.autodesk.com. [Accessed on 24 November 2017].

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Fig:2.07 Energy intensity for US Buildings, by program type (source: U.S. Energy Information Administration, Commercial Buildings Energy Consumption Survey) Available at: https://www.eia.gov/consumption/commercial/reports/2012/energyusage/

Fig:2.08 Simulated

Energy Intensities for an identical 4000 m2 office building in various EU countries (source: EECCA 2003)

Scheduling Smart scheduling of building occupancy can reduce the need for active heating and cooling in a building, by avoiding the times of day or year with the harshest climate. For instance, a school in a hot climate can lessen its cooling energy needs by not holding classes during the daytime in the hottest summer months.

02.1.3.1 Lighting Loads Lighting loads are the energy used to power electric lights; they make up nearly a third of EU commercial building energy use, but for residential buildings they are generally only 11%.

Lighting loads in a building are often referred to in terms of a “Lighting Power Density” that is measured in watts per square foot or square meter.

When deciding which lighting products to use, look at the efficiency (or luminous efficacy) of the products. More efficient light sources and fixtures not only reduce lighting loads, but also reduce cooling loads for the same visible brightness.

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Fig:2.09 Energy

consumption by end use in the EU domestic and commercial buildings (source: EECCA 2007)

02.1.3.2 Plug Loads Plug loads are the electricity used for other equipment, like computers and appliances; they make up 20 - 30% of energy loads in US commercial buildings, and 15 - 20% of home energy, though these numbers are growing as electronics become more pervasive.

Plug loads are sometimes included in “Equipment Power Density” (EPD) and sometimes they are separated. When doing building analysis, it’s important to know which value you’re inputting.

02.1.3.3 Equipment Loads Equipment, like HVAC systems and water heaters, is the other main internal load. This is typically separated from plug loads and is given in terms of an “Equipment Power Density,� which is measured in watts per square foot or square meter.

When deciding which equipment to use, look at third-party quantitative reviews, or read the maximum power use listed on product specification sheets (average power use data is usually not available because it can vary greatly by usage.) 7

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Fig:2.10 Example

Internal Loads for Different Space Types note that this information can vary greatly based on the design and use of the space. Use more precise and specific estimates when available.

(Sources: United States Department of Energy (1 and 2), and Mechanical and Electrical Equipment for Buildings

by Grondzik et al.)

7 Equipment and Lighting Loads | Autodesk Building Performance Analysis and sustainability workshop [webpage] sustainabilityworkshop.autodesk.com. [Accessed on 24 November 2017].

02.2 Building Energy Use measurement through Building Performance Analysis process in different project phases Knowing how to measure energy use in buildings will help to set better energy efficiency goals. Energy Use Intensity (EUI) normalizes energy use by floor area and is useful for targets and benchmarks. But, when it comes to environmental impacts, you need to look upstream at “source energy.” Also, when it comes to energy efficiency measures, you need to know what end-uses take the most energy.

02.2.1 Energy Use Intensity (EUI) When comparing buildings, people not only talk about total energy demands, but also talk about “energy use intensity” (EUI). Energy intensiveness is simply energy demand per unit area of the building’s floor plan, usually in square meters or square feet. This allows comparing the energy demand of buildings that are different sizes, to see which performs better.8

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Fig:2.11 Autodesk’s

Insight energy analysis tool report building performance in terms of EUI and Annual Cost (Sources: Autodesk Building Performance Analysis and sustainability workshop, Measuring Building Energy Use, sustainabilityworkshop.autodesk.com) 8 Measuring Building Energy Use| Autodesk Building Performance Analysis and sustainability workshop [webpage] sustainabilityworkshop.autodesk.com. [Accessed on 24 November 2017].

EUI is a particularly useful metric for setting energy use benchmarks and goals. The EUI usually varies quite a bit based on the building program, the climate, and the building size. The charts below, based on data from CBECS data from the United States, can give an idea of the range of EUIs to expect based on these parameters.

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Fig:2.12 Energy use (Source: CBECS 2003)

intensity & 2030 challenge targets by building type

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Fig:2.13 Energy use (Source: CBECS 2003)

intensity by building floor space

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Chapter 03 Green retrofitting design goals

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Thermal comfort

Visual comfort

Air quality

Acoustic comfort

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Fig:3.00 Occupant’s comfort different elements (Source: Mena ashraf, 2017, Why Building Green Matters)

/03 Green retrofitting design goals Architects, sustainable designers and engineers usually put in consideration some aspects before starting their sustainable design, the climatic approach and what are their design goals.

It should be made clear that the above discussion assumes that the design is new and not yet built skyscraper but the sustainable designer is always in his mind the bioclimatic approach before starting his project for both scenarios “Retrofitting for built skyscraper or design a new one”.

Bioclimatic design Approach for skyscrapers High performance sustainable designs can be defined as approach that uses the least possible amount of energy to maintain a comfortable interior environment, which promotes the health and productivity of the building’s occupants. This means that bioclimatic design approach is the building systems that create comfortable spaces by actively responding to the building’s external environment, and significantly reduce buildings’ energy consumption Average energy use for commercial buildings is shown in Figure 1-1. Heating, cooling, lighting, and ventilating interior spaces account for more than half of the energy use. The performance of the building facade can significantly affect the energy consumed by these building systems. Designers of sustainable facades should use the specific characteristics of a building’s location and climate, as well as its program requirements and site constraints, to create high-performance building envelopes that reduce the building’s energy needs. Climate-specific guidelines must be considered during the design process. Strategies that work best in hot and arid climates are different from those that work in temperate or hot and humid regions. In this chapter, the different ways of classifying climates, and the characteristics of each climate zone will be discussed. Also it will be discussed some of the factors that must be considered when designing high-performance sustainable facades for skyscrapers, based on climatic environmental characteristics.

Regardless of what type of building will be designed, the various environmental conditions, which are together described as “climate” (temperature, humidity, wind, precipitation, and sky conditions) will be one of the first and most important factors

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that you study in the design process. Not only does climate have big implications for the type of materials and constructions the designer want to use, it’s also going to tell him a lot about what types of passive design strategies are going to work in his favor.

Fig:3.01 Energy

use breakdown for commercial

buildings (Source: DOE, 2012)

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03.1 Design strategies behind green retrofitting for High Performance buildings What makes any building “comfortable”? All building’s facades create barriers between the exterior and interior environment, providing building occupants with thermally, visually, and acoustically comfortable spaces. Sustainable facades do more. Through different design strategies, they provide optimal levels of comfort using the least amount of energy. To achieve this high performance, designers need to consider many variables—thermal insulation, daylighting, solar shading, glare, acoustics, and indoor air quality—when designing facades for sustainable interior environments.

It is not an easy task for the designer to identify the priority of choosing which one of these variable he should start working on. So he has to identify his design strategy and policy according the available funds with the highest impact on the building performance.

Design Strategies Some ways to keep people comfortable are to use the sun’s heat to warm them, use the wind or ceiling fans to move air when it’s too warm, and keeping surrounding surfaces the correct temperature with good insulation. HVAC equipment like boilers, fans, and heat exchangers can temper the air temperature and humidity, but surface temperatures and moving air have to be considered too.

To keep people comfortable you’ll need to use the right combination of passive and active design strategies.

High-performance buildings use the right blend of passive and active design strategies to minimize energy, materials, water, and land use.

Passive design strategies use ambient energy sources instead of purchased energy like electricity or natural gas.

These strategies include daylighting, natural ventilation, and solar energy.

Active design strategies use purchased energy to keep the building comfortable. These strategies include forced-air HVAC systems, heat pumps, radiant panels or chilled beams, and electric lights.

Hybrid systems use some mechanical energy to enhance the use of ambient energy sources. These strategies include heat recovery ventilation, economizer ventilation, solar thermal systems, radiant facades and even ground source heat pumps might be included in this category.

In general, the designer will want to optimize his design for passive strategies first. Doing so can often downsize the active systems he will need to install.1 Passive Design Strategies which is our focus in this study for heating, cooling & ventilation will be well elaborated more specially for skyscrapers, but the first step to affordably producing as much energy as the building consumes is lowering the amount of energy it takes to keep the building comfortable through maintaining the right interior temperature, humidity and air quality, often accounts for 30% or more of a building’s energy use (HVAC).

1 Peter A. Brown CEng, MBA (2010), Passive & Active Design, CIBSE Building Simulations Group , page 4.

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Designing passively means working with the external weather conditions instead of fighting against them. For example: (building orientation, overhangs, etc.) can be designed to capture the sun’s heat in cold times and avoid it in hot ones.

There is “no one size fits all” passive design strategies.

To start, the designer needs to understand the building site’s climate, and how heat energy is transferred through conduction, radiation, and convection. When heat passes through the building materials, that’s “conduction”. It can be reduced it by using insulation with high R-values and windows with low U-values.

Conduction isn’t always a bad thing. For instance, the ground stays at a relatively constant temperature, so you can conduct excess heat into it in the summer or pull heat from it in the winter. (Fig: 3.02)

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Fig:3.02 Ground heat conduction (Sources: redraw by the auther from Autodesk Building Performance Analysis and sustainability workshop, Passive Design Strategies for Heating, Cooling, & Ventilation, sustainabilityworkshop.autodesk.com)

Radiation, in the form of sunlight, is another major source of energy gains, the sun heats buildings, especially on dark roofs and pavement. It can be minimized unwanted heat gains by choosing more reflective surfaces, or vegetation.

(Fig: 3.03) Energy also radiates in and out of buildings through windows. The designer can make windows work for better performance by optimizing the window-to-wall ratio on each side of the building, and choosing windows that optimize how as infrared, visible light, and higher-frequency radiation.

Fig:3.03 Sun radiation on the roof surface (Sources: redraw by the auther from Autodesk Building Performance Analysis and sustainability workshop, Passive Design Strategies for Heating, Cooling, & Ventilation, sustainabilityworkshop.autodesk.com)

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Fig:3.04 Energy passes through windows (Sources: redraw by the auther from Autodesk Building Performance Analysis and sustainability workshop, Passive Design Strategies for Heating, Cooling, & Ventilation, sustainabilityworkshop.autodesk.com)

Convection, when heat energy is transferred by moving fluids, like air. Air is constantly circulating within buildings due to temperature and pressure differences.

Anyone who’s been in a drafty building knows how powerful convection can be in moving heat: Air leaks cause up to 40% of building heat loss. But you can stop this, by sealing the building well. Convection happens inside building elements, too. Installing Argon-filled windows and triple-pane windows reduces the convection of heat between panes.(Fig: 3.05)

Fig:3.05 Insulated windows (Sources: redraw by the auther from Autodesk Building Performance Analysis and sustainability workshop, Passive Design Strategies for Heating, Cooling, & Ventilation, sustainabilityworkshop.autodesk.com) 64

Of course, the designer can use convection to his advantage by transferring energy where he wants it and bringing people fresh air. The wind can bring cool fresh air into his building, and reduces the energy he might need for fans.

He can control it with the size of the building’s window openings, and place openings to take wind direction into account. (Fig: 3.06) 2

2 Justin Wilson, Construction Instruction, inc (2014), How Heat Flows and How to Stop It, page 31.

Fig:3.06 Opening placement (Sources: redraw by the auther from Autodesk Building Performance Analysis and sustainability workshop, Passive Design Strategies for Heating, Cooling, & Ventilation, sustainabilityworkshop.autodesk.com)

Throughout the year, and even throughout the day, environmental conditions change, so your building needs to adapt.

Sensors and electronic controls can be used to turn lights off, open shades, and even change windows from clear to tinted.

03.2 Design Goals for high performance buildings After deciding your design strategy as an environmental designer, you have also to identify the priorities for choosing your design solution but not only you should also be aware about the main design goals for high performance buildings Skyscrapers are designed for people, and those people are trying to accomplish a task – whether it’s raising a family, running an office, or manufacturing a product. This building needs to keep people comfortable, efficient, healthy, and safe as they set about their task.

Green design seeks to create buildings that keep people comfortable while minimizing negative environmental impacts.

To achieve this comfortable point, the designer should focus on different aspects of comfortableness.

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03.2.1 Thermal comfort Maintaining a person’s thermal comfort means ensuring that they don’t feel too hot or too cold. This means keeping the temperature, humidity, airflow and radiant sources within acceptable range.

Thermal comfort is defined by ASHRAE as “that condition of mind which expresses satisfaction with the thermal environment” (ASHRAE, 2004). Because it is a condition of mind, comfort is inherently based on one’s experience and perception; there are large variations in physiological and psychological responses for different individuals. Few buildings are designed to meet the unique thermal comfort needs of a single person. Therefore, organizations such as ASHRAE have established standards for thermal comfort that apply to the majority of people most of the time. 3 03.2.1.1 Why it’s important Creating comfortable conditions is one of the biggest uses of energy in buildings and it is also critical to the happiness and productivity of its users. Often factors such as airflow and radiant temperature are overlooked in a design, leading to higher energy use and occupancy dissatisfaction.

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Energy-efficient skyscrapers are only effective when the occupants of the buildings are comfortable. If they are not comfortable, then they will take alternative means of heating or cooling a space such as space heaters or window-mounted air conditioners that could be substantially worse than typical Heating, Ventilation and Air Conditioning (HVAC) systems.

03.2.1.2 Metrics To keep people comfortable you need to provide the right mixture of temperature, humidity, radiant temperature and air speed. The right level of these variables depends on what activity is occurring, how active the people are, and what they are wearing. Everyone has slightly different criteria for comfort, so comfort is often measured by the percentage of occupants who report they’re satisfied with the conditions.

Thermal comfort is difficult to measure because it is highly subjective. It depends on the air temperature, humidity, radiant temperature, air velocity, metabolic rates, and clothing 3 Aksamija, Ajla, (2014), Sustainable facades, Thermal comfort, page 139.

levels and each individual experiences these sensations a bit differently based on his or her physiology and state.

Factors in Human thermal Comfort There are six factors to take into consideration when designing for thermal comfort. Its determining factors include the following: • Metabolic rate (met): The energy generated from the human body • Clothing insulation (clo): The amount of thermal insulation the person is wearing • Air temperature: Temperature of the air surrounding the occupant • Radiant temperature: The weighted average of all the temperatures from surfaces surrounding an occupant • Air velocity: Rate of air movement given distance over time • Relative humidity: Percentage of water vapor in the air.

The environmental factors include temperature, radiant temperature, relative humidity, and air velocity. The personal factors are activity level (metabolic rate) and clothing.

Thermal comfort is calculated as a heat transfer energy balance. Heat transfer through radiation, convection, and conduction are balanced against the occupant’s metabolic rate.

The heat transfer occurs between the environment and the human body, which has an area of 19 ft2 (1.81 m2) . If the heat leaving the occupant is greater than the heat entering the occupant, the thermal perception is “cold.” If the heat entering the occupant is greater than the heat leaving the occupant, the thermal perception is “warm” or “hot.”

A method of describing thermal comfort was developed by Ole Fanger and is referred to as Predicted Mean Vote (PMV) and Predicted Percentage of Dissatisfied (PPD).

Predicted Mean Vote The Predicted Mean Vote (PMV) refers to a thermal scale that runs from Cold (-3) to Hot (+3), originally developed by Fanger and later adopted as an ISO standard. The original data was collected by subjecting a large number of people (reputedly many thousands of Israeli soldiers) to different conditions within a climate chamber and having them select

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a position on the scale the best described their comfort sensation. A mathematical model of the relationship between all the environmental and physiological factors considered was then derived from the data. The result relates the size thermal comfort factors to each other through heat balance principles and produces the following sensation scale.4

Fig:3.07 ASHRAE thermal sensation scale (Sources: Study on Sensor Fusion for Predicting Human’s Thermal Comfort Accounting for Individual Differences by Using Neural Network. omicsonline.org)

The recommended acceptable PMV range for thermal comfort from ASHRAE 55 is between -0.5 and +0.5 for an interior space

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Predicted Percentage of Dissatisfied Predicted Percentage of Dissatisfied (PPD) predicts the percentage of occupants that will be dissatisfied with the thermal conditions. It is a function of PMV, given that as PMV moves further from 0, or neutral, PPD increases. The maximum number of people dissatisfied with their comfort conditions is 100% and, as you can never please all of the people all of the time, the recommended acceptable PPD range for thermal comfort from ASHRAE 55 is less than 10% persons dissatisfied for an interior space.

For naturally ventilated spaces, where occupants have some control over their environment (e.g., by opening or closing windows to alter air temperature and air movement), the ASHRAE standard provides an optional method for determining thermally acceptable conditions. Indoor operating temperatures can be adjusted up or down, depending on the mean monthly outdoor temperatures, while still maintaining acceptable comfort conditions.

This is illustrated in (Fig3.09), which specifies ranges of operating temperatures for acceptable thermal comfort in naturally ventilated buildings.

4 Aksamija, Ajla, (2014), Sustainable facades, Thermal Methods of Measurement, page 141.

Fig:3.08 Relationship between PMV and PPD indices (Sources: Study on Comfort modelling in semi-outdoor spaces. rehva.eu)

Higher operating temperatures are acceptable for climates with high mean monthly temperatures, significantly reducing energy consumption by mechanical systems. This allows for 10% of the occupants to experience whole-body thermal discomfort, and for an additional 10% to experience thermal discomfort for some part of their bodies. For example, if the mean monthly outdoor temperature is (35°C), the indoor operating temperatures can be relatively high, between approximately (24°C) and (30.5°C), and still satisfy 80% of the occupants. At the other extreme, if the mean monthly outdoor temperature is (10°C), the indoor operating temperatures can be relatively low, between approximately (17.5°C) and (25°C).

Fig:3.09 Acceptable

operating temperatures for naturally conditioned (Sources: ASHRAE 2004)

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CBE model The Center for the Built Environment (CBE) at the University of California at Berkeley (UCB) has developed a more advanced model for understanding and determining occupants’ thermal comfort. It relies on complex relationships between environmental conditions and the physiological response of an occupant, who is represented in the model by a “thermal manikin” (Huizenga et al., 2001). In the CBE model, thermal comfort is related to the principles of human thermal regulation. To differentiate local thermal comfort, the thermal manikin can be monitored at an arbitrary number of body segments, such as head, chest, arms, and legs. Most applications use sixteen body segments. Figure 14 shows how the thermal manikin can be used to reflect characteristics of actual users, such as level of clothing, metabolic rate, and physiological properties. Convection, conduction, and radiation of heat between the manikin and the environment are considered in the calculations. 5

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Fig:3.10 Thermal manikins and comfort responses (Sources: The Center for the Built Environment (CBE) at the University of California at Berkeley (UCB) 5 Aksamija, Ajla, (2014), Sustainable facades, Thermal Methods of Measurement, page 145.

03.2.1.3 Thermal Comfort through Facades elements design Of all the facade elements, windows have the largest thermal fluctuations. Windows are usually the coldest interior surfaces in cold weather and the warmest interior surfaces in warm weather. This is the case even for windows with high-performance glazing and thermally broken frames. As a result, facades with high window-to-wall ratios (WWRs) are more likely to affect the thermal comfort of occupants than those with low WWRs. This effect increases as occupants get closer to the window, and also depends on how active the occupants are.

For example, occupants who spend most of the time seated close to the windows are more likely to feel discomfort than occupants seated farther away or moving within the space.

The optimal WWR should be based on the floor plan of a space, the occupants’ positions in the space, and the types of occupant activities. Smaller WWRs should be used for spaces where occupants are typically close to the windows, especially for south-oriented facades. For example, in the design of commercial office spaces where the occupants are seated near windows, the WWR should not exceed 40%, and WWRs as low as 25% should be considered. For spaces where occupants do not spend a lot of time near windows, or for corridors and other circulation spaces, higher WWRs can be used with minimal effect on the occupants’ thermal comfort. Window size is not always entirely the designer’s choice; in some cases, such as hospital patient rooms, building codes or other standards may prescribe minimum window sizes.

The choice of facade glazing materials also influences occupants’ thermal comfort. The effects are different for summer and winter. During winter, the thermal comfort effect is largely driven by inside window surface temperature, which is usually colder than the room it faces. (Fig:3.11) shows, for six common glazing types, the lowest outdoor temperature at which a person seated one meter from a window would feel comfortable. The table shows that double-glazed, air-insulated, low-e glazing units are suitable for climates where winter exterior temperatures are above (– 6°C), while triple-glazed, air-insulated, low-e glazing units can be used for temperatures as low as (–28°C).

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During the summer, thermal comfort is driven by the combination of the inside surface temperature of the glass and the transmitted solar radiation through the glass. These in turn are significantly influenced by the construction of the glazing units, the material properties of the glass, and the effectiveness of shading elements used with the window. (Fig:3.11) shows, for the same six glazing types, the maximum amount of solar radiation on the surface of the glass before an occupant seated close to a window starts to feel uncomfortable.

As we can see, spectrally selective double-glazed, airinsulated, low-e glazing units are the best choice for climates with high solar radiation. These types of glazing units have a light-to-solar-gain ratio of 1.25 or higher (i.e., they have high visual transmittance and low SHGC), allowing large amounts of daylight to enter the interior while blocking much of the solar heat. 6

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Fig:3.11 Glazing

systems and winter and summer environmental conditions for meeting thermal comfort of occupants seated close to a window (Sources: Huizenga et al., 2006, Window performance for human thermal comfort)

Air infiltration can have a much more significant effect on comfort. Although facades cannot be built fully airtight, infiltration resistance can be achieved if the assembly is designed with an appropriate air barrier. Air leakage can be aggravated if the interior air pressures are significantly different from the exterior air pressure. These internal pressure differences can be created by the HVAC system or by the varying vertical air pressures in tall buildings (stack effect). Significant pressure differences between the interior and the exterior of the 6 Huizenga, C, Zhang, H., Mattelaer, P., et al. (2006), Window performance for human thermal comfort, Available at: https://escholarship.org/uc/item/6rp85170, Page:59

building can cause air to be driven through the facade if there are penetrations in the air barrier. This will result in outside air being pulled into the space or conditioned interior air being driven out of the building, requiring more internal air to maintain thermal comfort.

03.2.1.4 Summary Designers have four design strategies available to improve the thermal comfort of a building’s occupants: • Find the optimal window-to-wall ratio (WWR). In some conditions, it is better to have more windows or larger windows to bring in more daylight, whereas in other conditions it is better to have fewer or smaller windows for increased wall insulation and better acoustics. The optimal WWR strikes a balance between all thermal comfort factors and other factors that give the occupants the best overall comfort.

• Select glazing materials with the best performance characteristics, especially solar heat gain coefficient and U-value.

• Design shading elements to reduce interior solar heat gain during warm seasons, while allowing direct sunlight to provide warmth during cold seasons.

• Provide a facade assembly strategy that will be as airtight as possible, with all gaps sealed to limit uncontrolled movement of air through the facade. This will keep exterior air from penetrating the exterior wall and conditioned air within the interior space.

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03.2.2 Visual Comfort Maintaining visual comfort means ensuring that people have enough light for their activities, the light has the right quality and balance, and people have good views.

03.2.2.1 Why it’s important Good lighting helps create a happy and productive environment. Natural light does this much better than electric lighting. Having good views and sight-lines gives people a sense of control of their environment and provides a sense of well-being.

Natural light and artificial light

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Research has shown that the benefits of daylight extend beyond energy savings to include the positive physiological and psychological well-being of people. Exposure to natural light positively affects people’s circadian rhythms, which can lead to higher productivity and greater satisfaction with the internal environment (Edwards and Torcellini, 2002). Different wavelengths and spectral distributions of light have different effects on the human body, and daylight, unlike most artificial light sources, includes the full spectral distribution of wavelengths needed for biological functions. For this reason, people subconsciously prefer daylight to any type of artificial lighting (Liberman, 1991) 7. Studies have shown that in commercial office spaces, daylight promotes increased productivity, improved health of occupants, reduced absenteeism, and financial savings. In educational facilities, the benefits include improved student attendance and academic performance.

Research also suggests that natural light in hospitals and assisted-living facilities improves the physiological and psychological states of patients and staff (Edwards and Torcellini, 2002).8 Though few (if any) negative effects result from exposure to daylight, exposure to direct sunlight has both good and bad effects. For example, when the ultraviolet radiation in sunlight hits human skin, the skin produces the essential vitamin D. However, too much sunlight on skin can cause tissue damage. Window glass usually blocks most of the sun’s ultraviolet radiation from reaching interior spaces.

7 Liberman, J. (1991). Light Medicine of the Future. Santa Fe, NM: Bear & Co. 8 L. Edwards and P. Torcellini, (2002), A Literature Review of the Effects of Natural Light on Building Occupants, page 36.

03.2.2.2 Metrics Good lighting is well-distributed, is not too dim or too strong, and uses minimal energy. Lighting is often measured either by the amount of light falling on a surface (illuminance) or the amount of light reflecting off of a surface (luminance). These are objective measures, but how people experience this light is often subjective (i.e. are they comfortable?, do they experience glare?). Good visual comfort also generally means that as much of this light is natural light as possible. Humans are hard-wired to like the sun’s light and it saves energy.

Fig:3.12 Light measuring units (Sources: Autodesk Building Performance Analysis and sustainability workshop, Daylighting Strategies, sustainabilityworkshop.autodesk.com)

The Illuminating Engineering Society recommends ranges of illuminance levels for different types of spaces and tasks, which are published in the IESNA Lighting Handbook (IESNA, 2011).

For example, public spaces with dark surroundings require from 2 to 5 fc (20 to 50 lux); work areas where visual tasks are occasionally performed require from 10 to 20 fc (100 to 200 lux); and spaces where detailed visual tasks are performed for prolonged periods of time require from 200 to 500 fc (2,000 to 5,000 lux).9

9 LIlluminating engineering society, (2011), The Lighting Handbook, 10th Edition.

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03.2.2.3 Design Strategies Designers of naturally lit spaces need to consider the project’s design goals and criteria, and its fixed and variable conditions. Design goals and criteria include subjective qualities, such as privacy and views to the outside, as well as objective and measurable qualities, such as energy use and the intensity of the daylight. They are set either by the project team (for example, views to the outside) or by prevailing codes, zoning ordinances, and standards. When considering visual comfort, designers need to think about illumination levels, daylight distribution, and protection against direct sunlight and glare.

Integration of building systems is also important, because facades, lighting, shading elements, HVAC systems, and building controls must function together to have the largest effect on building performance. For example, spaces that use natural daylight for perimeter zones and control artificial lighting with photosensors and dimmers reduce the cooling loads for the HVAC system and, most likely, the sizes of mechanical equipment and ductwork.

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Fixed conditions are outside the designer’s control. They include the building’s location and the climate, which determine, respectively, the position of the sun and the outdoor temperature, and the surrounding buildings, trees, topography, and other features that can affect daylight availability and views. Designers can control the variable conditions, such as building geometry and the design of the facade, including material properties, size and orientation of windows, and shading of windows. By understanding the fixed conditions, and carefully manipulating the variable ones, designers can create spaces that use daylighting to enhance occupants’ visual comfort.

The orientation and WWR of a building influence the availability of natural light for interior spaces. Analyzing daylight availability during the different seasons is an important part of the design process for high-performance sustainable facades.

Lighting simulation software programs, such as Radiance, developed by the Lawrence Berkeley National Laboratory, can be used to simulate and study different design options.

A successful daylighting strategy depends on how much daylight reaches the building envelope. Locations with predominantly cloudy skies require different daylighting strategies

Fig:3.13 Daylight design considerations (Sources:Aksamija, Ajla, (2014), Sustainable facades, Daylighting Strategies, page 153)

from those with mostly clear skies. (Fig 3.14) shows strategies that are effective in locations where cloudy skies predominate.

Large windows located high and equipped with light shelves can be effective. Where clear skies predominate, strategies that control direct sunlight, such as reduction of window size and the use of shading elements, should be applied. (Fig 3.15) shows effective strategies in these locations. (Fig 3.16) is a table lists different strategies and their applicability for various sky conditions, climates, and design criteria.10

10 Aksamija, Ajla, (2014), Sustainable facades, Daylighting Strategies, page 153.

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Fig:3.14 Diagram of light (Sources: Ruck et al., 2000)

shelf performance in summer and winter.

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Fig:3.15 Diagram

showing daylight facade strategies for locations with predominantly cloudy sky conditions (Sources:Ruck et al., 2000)

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Fig:3.16 Diagram

showing daylight facade strategies for locations with predominantly sunny sky conditions 11 (Sources:Ruck et al., 2000)

11 N. Ruck, S. Aydinli, Ă˜yvind Aschehoug, Stephen Selkowitz (2000), Daylight in Buildings - A source book on daylighting systems and components.

Fig:3.17 Applicability of (Sources:Ruck et al., 2000)

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different daylight facade strategies

03.2.3 Acoustic Comfort Acoustic comfort means having the right level and quality of noise to use the space as intended.

03.2.3.1 Why it’s important People are more productive and happy when they’re not distracted by noises from outside or from surrounding spaces and occupants. Acoustic comfort is especially important for schools and office buildings.

03.2.3.2 Metrics How humans perceive sounds and loudness is a subjective measure. However, you can create a comfortable environment by controlling objective measures like decibel level

(sound pressure), reverberation time, and the sound reflection and damping properties of materials.

There are a number of established methods for evaluating the acoustic quality of an interior space. These are shown in Fig-- .

Each method evaluates a different aspect of acoustic performance, and not all of them are relevant to facade design.

Fig:3.18 Acoustic comfort factors for interior spaces (Sources:Aksamija, Ajla 2013, Sustainable Facades, ACOUSTIC COMFORT AND AIR QUALITY, p. 185 )

The sound transmission class (STC) rating system is one way to represent the acoustic experience of an occupant in a room. Partition and floor assemblies are tested to determine their STC ratings. STC is a measure of acoustic performance for a range of frequencies (125 to 4,000 Hz) that encompass most everyday interior sounds, particularly human speech. The International Building Code specifies that walls, partitions, and floor and ceiling assemblies between dwellings, and between dwellings and public spaces, should have an STC rating of 50 or more for airborne sound (ICC, 2012). Impact insulation class (IIC) rating is similar to STC; however, it represents the transmission of impact sounds through the structure, particularly floors or ceilings. 12 The STC rating system was introduced in 1970, and has become the standard tool for the acoustic design of interior partitions and floor assemblies. However, because the system is based on the mid- and highfrequency sounds associated with human speech and normal household activities, it has proven inadequate for low-frequency exterior sounds. ASTM, in its E413 standards that govern STC ratings, states that the 12 ICC. (2012). 2012 International Building Code. Country Club Hills, IL: International Code Council

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STC classification method is not appropriate for some sound sources, such as motor vehicles, aircraft, and trains (ASTM, 2010).

Another method for evaluating the acoustic performance of constructed assemblies, the Outdoor-Indoor Transmission Class (OITC), was introduced in 1990 specifically for normal exterior sounds—particularly those generated by an aircraft taking off, a nearby railroad, or a busy freeway (i.e., planes, trains, and automobiles). The OITC’s range of frequencies, from 80 to 4,000 Hz, includes all the STC frequencies, as well as lower frequencies. Like the STC ratings, the OITC system uses a single number to rate the acoustic performance of a product or an assembly of materials. For both STC and OITC, the higher the number, the better a product or assembly will perform acoustically.

Calculations to determine OITC ratings must be based on carefully controlled laboratory or field tests of a product or assembly. Many manufacturers of standard windows, doors, curtain walls, insulation, and joint seals provide OITC ratings for their products. However, custom systems and assemblies often must be tested, either in an acoustic testing facility or in the field, to determine their OITC ratings.

For high-performance facades, ASHRAE recommends a composite OITC of at least 40. Fenestration areas should have an OITC rating of at least 30 (ASHRAE, 2009). 13 82

03.2.3.3 Design Strategies Creating barriers and sound breaks between sources of noise is important. You can optimize room shape and size to reduce echoes and reverberation. And you can use acoustic tiles on ceilings and walls to dampen the sound.

Designers can follow these general principles to improve the acoustic performance of a facade: • Increase the mass of the materials. In general, the more massive a material is, the higher the sound transmission loss will be.

• Match the resonant frequency of the materials to the predominant sound waves. When the frequency of the sound waves matches the resonant frequency of the materials, energy is absorbed, resulting in higher sound transmission loss.

13 ASHRAE. (2009). ANSI/ASHARE/USGBC/IES Standard 189.1 for the Design of High-Performance Green Buildings. Atlanta, GA: American Society of Heating, Refrigerating, and Air-Conditioning Engineers, Page:60.

•

Increase the width of air spaces.

• Provide acoustic breaks. Similar to thermal bridges, solid materials that bridge across air spaces will help sound waves pass through a wall. Acoustic breaks will hamper sound transmission.

• Fill air spaces in opaque walls with insulation materials with desired thermal and acoustic performance ratings.

• Use layers of different materials. This will create discontinuities in the wall, making it more difficult for sound waves to move from one material to the next.

• Finally, and perhaps most basically, seal air leaks in the wall assembly. Air leaks give sound waves a continuous path through a single medium (air) from the outside to the inside.

Some of these principles apply only to opaque walls. For glazed facades, designers have other strategies available for improving acoustic performance: • Thicker glass will increase the mass that the sound waves have to pass through. However, unless unusually thick glass is required for other reasons (ballistic resistance, for instance), this approach is not an economical way to significantly improve acoustic performance. Increasing the thickness of the glass from ¼ inch to ½ inch will increase the OITC from 29 to 33, and the STC from 31 to 36.

• Laminated glass will improve the acoustic performance of single-glazed windows. The laminated inner layer creates a discontinuity of materials that dampens the sound vibrations. A nominal 1/4-inch lite of laminated glass, consisting of two layers of 1⁄8-inch glass and a 0.060-inch-thick laminate interlayer, will have an OITC of 32 and an STC of 35.

• Standard air-filled insulating glass units will perform better than most single-glazed windows (1-inch-thick insulating unit with 1/2-inch air space will have an OITC of 26–28 and an STC of 31–33).

• Using laminated glass for one or both lites in a 1-inchthick, air-filled insulating unit will further increase its acoustic performance. With one lite of 1/4-inch laminated glass, the OITC of the insulating unit increases to 28–30, and the STC increases to 34–36. When both lites are 1/4-inch laminated glass, the OITC and STC increase to 29–31 and 37–39, respectively. 14 14 Aksamija, Ajla, (2014), Sustainable facades, Daylighting Strategies, page 153.

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• Triple-glazed insulating units, with the middle lite being either glass or a laminate membrane, will further enhance the acoustic performance.

• When the insulating unit is constructed with a “soft” separation between the lites of glass, the acoustic performance will be improved.

• Adding a secondary interior lite of glass, separated from the outer insulating unit by a substantial air space, will result in still better acoustic performance. An assembly consisting of a standard 1-inch insulating unit, a 2-inch air space, and an inner lite of 1/4-inch glass will have an OITC of 32–35 and an STC of 42–44. When laminated glass is used for one lite of the insulating unit and for the single interior lite, the OTC is 35–37 and the STC is 44–46.

03.2.4 Air Quality In addition to air that’s the right temperature and humidity for thermal comfort, it’s important that air is clean, fresh, and circulated effectively in the space.

03.2.4.1 Why it’s important If air is too stale or is polluted, it can make people uncomfortable, unproductive, unhappy, and sick. Fresh air helps people be alert, productive, healthy, and happy.

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03.2.4.2 Metrics Fresh air requires a certain percentage of outside air circulating into spaces. Clean air requires pollutant and pathogen levels to be below certain thresholds.

Acceptable indoor air quality (IAQ) is defined as indoor air that has no contaminants at harmful concentrations and that satisfies at least 80% of the occupants (ASHRAE, 2007). 15 As people breathe in oxygen and breathe out CO2, air becomes “stale”; when CO2 concentrations are too high, occupants become tired, less happy, and have difficulty concentrating. Bringing in fresh outside air with plenty of oxygen keeps people happier, more energetic, and more alert. The LEED rating system has credits for both meeting and exceeding ASHRAE standards for fresh air.

15 ASHRAE. (2007). ANSI/ASHRAE Standard 62-1-2007 Ventilation for Acceptable Indoor Air Quality. Atlanta, GA: American Society of Heating, Refrigerating, and Air-Conditioning Engineers.

How much outside air is enough? It depends on the program of the room. ASHRAE 62.1 Table 6.1 has a long list of minimum outdoor air requirements for different types of room, from offices to gymnasiums to bank vaults. A small sample is below.

Fig:3.19 Sample of minimum outdoor air requirements for different programs (Sources:ASHRAE. (2007). ANSI/ASHRAE Standard 62-1-2007 Ventilation for Acceptable Indoor Air Quality.)

03.2.4.3 Design Strategies Air can be kept fresh with high ventilation rates, either using natural ventilation such as operable windows and skylights, or active systems such as HVAC fans and ducts. Clean air can be achieved by filtering air, by flushing spaces with fresh outside air, and by not contaminating the air with impurities from the building, such as volatile organic compounds from paints or materials.

Impurities in air can be avoided by eliminating the sources of impurities, flushing out spaces with clean air, and by filtering the air to remove impurities.

Filtering generally increases the energy use of HVAC systems by increasing the resistance to air flow, but filters with larger surface area can be chosen to reduce resistance. Flushing out spaces with clean air is generally done between construction and occupancy.

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Eliminating impurity sources is generally done by four methods: 1- Avoiding mold and mildew by avoiding condensation in building materials and HVAC systems 2- Installing floor grates to avoid dirt being tracked into the building 3- Banning smoking in the building and near HVAC air inlets 4- Choosing interior finish materials that do not offgas volatile organic compounds (VOC’s) Both the LEED rating system and the Living Building Challenge have credits for three out of four of these strategies.

Avoiding Mold Mold and mildew are extremely common indoor air pollutants, especially in humid climates. The simplest way to avoid them in the building envelope is to avoid condensation. To avoid condensation in the envelope, the best techniques are to let the building envelope breathe (so that moisture occurring in the envelope can escape), or to have the envelope’s dewpoint occur in the middle of a solid material, such as closed-cell spray foam (so there’s no moisture present to condense). 16

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Fig:3.20 Avoiding mold by avoiding condensation points (Sources:Autodesk Building Performance Analysis and sustainability workshop, Indoor Air Quality, sustainabilityworkshop.autodesk.com)

Many building operation measures can help prevent mold growth, as well. Some recommendations from the US EPA and US CDC are these: 16 EPA. (2013).Moisture Control Guidance for Building Design, Construction - EPA

• Design the building envelope to avoid condensation within walls and other constructions.

• Vent showers and other moisture-generating sources to the outside.

• Control humidity levels and dampness by using air conditioners and de-humidifiers.

• Provide adequate ventilation to maintain indoor humidity levels between 30-60%.

• Use exhaust fans whenever cooking, dishwashing, and cleaning in food service areas.

• Clean and dry any damp or wet building materials and furnishings within 24-48 hours of occurrence to prevent mold growth.

Materials for Clean Air Certain types of materials and finishes are very prone to emitting volatile organic compounds (VOCs) and other pollutants.

Controls Some advanced building information management systems adjust the rates of incoming outdoor air to keep indoor air fresh enough and clean enough without using too much energy.

These control systems use CO2 sensors to test the freshness of air; especially advanced ones even use pollutant sensors (particulates, VOCs, or others) to measure air cleanliness.

Such systems can help conserve energy by only running ventilation systems when necessary for occupant health and happiness. These may include Demand-Controlled Ventilation (DCV) or Supply Air CO2 Control(SACO2).17

Fig:3.21 Carbon

monoxide, carbon dioxide, and volatile organic compound sensors at the Pacific Energy Center.

(Sources:Autodesk Building Performance Analysis and sustainability workshop, Indoor Air Quality, sustainabilityworkshop. autodesk.com) 17 EPA. (1999).Indoor Air Quality and Energy Efficiency - EPA

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Chapter 04 Green Retrofitting for Skyscrapers

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Fig:4.0 Benefits of green retrofitting (Sources:Mahtot Gebresselassie, 2014 Quick Facts About Green Retrofitting)

/04 Green Retrofitting for Skyscrapers The U.S. Green Building Council (USGBC) define the green retrofit as “any kind of upgrade at an existing building that is wholly or partially occupied to improve energy and environmental performance, reduce water use, and improve the comfort and quality of the space in terms of natural light, air quality, and noise—all done in a way that it is financially beneficial to the owner”.

Overview on green retrofitting In addition the building and its equipment must be maintained to sustain these improvements over time. The green retrofit strategies manages the range between minor works for example installing new heating, ventilating, and air-conditioning components, mounting solar panels on a roof, or placing a bike rack outside the building; to a major works as multiple complex renovations on both the building’s interior spaces and exterior facades. While some investors may decide to do the retrofit project for their building at once, others may start the retrofit in stages by beginning first with changing the entire lighting systems, later, adding window films, and then replacing the Heating, Ventilation and Air Conditioning (HVAC) system, for example.

In these days, green retrofitting for buildings is an important development taking place worldwide. A lot of countries doing efforts to make buildings more environmentally sustainable. However, there are remaining a lot to do for buildings worldwide that need green retrofit to improve its performance on energy and sustainability. A new Pike Research, the global retrofitting market will expand from $80.3 billion in 2011 to $151.8 billion by 2020.1 “Retrofitting existing buildings offers one of the most cost-effective ways for a business to reduce its operating expenses” says senior analyst Eric Bloom 2. To describe it we should know that many energy preservation measures can be implemented within strict investment criteria, budget, and increasing of financial instruments are deepening the scope of energy efficiency retrofits, driving continued investment in energy efficient facades elements, HVAC, lighting, and control systems.

1 Kheir Al-Kodmany, (2014), Green Retrofitting Skyscrapers: A Review 2 Pike Research., (2012), Energy Efficiency Retrofit Market to hit $152 Billion, Available at: https://www.the-esa.org/news/articles/-/energy-efficiency-retrofit-market-to-hit-152-billion

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In this study interest area, Western Europe is the largest market for energy efficiency retrofits in commercial and public buildings, but because of Asian pacific market the EU’s share of world revenues will drop from 41% in 2011 to 37% in 2020. Essentially Asia Pacific represented 32% ($26 billion) of the revenue stream in 2011, will increase to 36% ($54.6 billion) by 2020. North American energy efficiency increasing to $35.3 billion by 2020. The German government has committed to reducing the primary energy demand of buildings by 80% by 2050, doing thermal retrofits on 2% of its building stock every year. To achieve these goals will require thermal retrofits across the existing buildings. In Italy also since 2007 the government has been offering tax incentives for energy efficiency improvements to existing buildings. Their program provides tax credits to households and companies for single retrofit measures such as thermal insulation, installation of solar panels, and replacement of heating and air-conditioning systems, or for comprehensive retrofit work. In the U.S., 5 million commercial buildings are due to green retrofit. The USGBC council also explains in the United States, the market for major green renovations was $2.1 billion a year at 2009 and grew to over $6 billion a year by 2013. Further, it estimates each year 2% of existing space is renovated, and 10% of these renovations include energy efficiency.

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Researchers and developers define green retrofit as the way to develop the “three R’s” (reduce, reuse, recycle) by extending the life time of the building with saving on the building demolition’s costs and acquisition of new building materials.

Simply, it makes no sense to demolish a building when it is possible to sustainably renovate it. As far as vertical density is increasingly as a critical element to support sustainability so the travel distances will be shorter and providing walkable environments. Most importantly, the green retrofitting for tall buildings is fundamental to combat climate change.3 04.1 Retrofit drivers 04.1.1 Economics Many of the skyscrapers are aging and are becoming increasingly inefficient on energy use as explained in chapter 01. Also, in the wake of the 2008 economic crisis the costs of utilities increased coupled with the falling commercial rents forced the investors to search for ways to reduce energy use and waste. Fortunately, green retrofit projects increasingly 3 Ellen Kollie, (2012), The New Three R’s, Available at: https://webspm.com/articles/2012/10/01/the-new-three-rs.aspx

make good economic sense after becoming big industry the sustainable devices become cheaper, and renovation costs will likely be recouped via energy savings in several ways. Further, real estate industry is addressing a new fact that energy efficient buildings command better rents and are increasingly desirable as the tenants will spend less money on the utility bills. Most of tenants recognize the potential savings resulting from increased productivity; they demand new and upgraded green buildings. Additionally, the growing green industry is now more viral through promoting their green projects and making their products and services known to the global market. Finally, the way to convince the skyscraper’s owner or the investor is to show the greatest potential saving to be gained via the increased workforce productivity facilitated by the healthier workspace. Another study shows if an organization could manages to boost employees’ productivity by 10%; the result equals to the cost of renting the space.4 In New York City, the iconic skyscraper Empire State Building is a 102-story building having a recent $20-million retrofit, which included everything from cleaning and re-insulating more than 6,000 windows to caulking leaks in the building’s facade reduced energy use by nearly 40 percent with $4.4M annual energy savings.

Another example applied in China’s 13th Five Year Plan for Building Energy Efficiency and Green Building Development includes aggressive goals for green building construction and renovation, including a requirement for 50% of all new urban buildings to be certified green buildings, also it specifies pilot programs for constructing and renovating energy efficient primary and secondary schools, community hospitals and public buildings. The program launch included government, private-sector and civil society stakeholders and showcased the building efficiency policy best practices of three leading Chinese districts. The Changning District in Shanghai prevail a platform for energy monitoring that now tracks 160 out of 165 district’s public buildings. Until June 2017, 32 buildings have been retrofitted to achieve an average 20% energy saving. The district also provided subsidies to building managers, which in turn encouraged building managers to invest an additional 140 million yuan ($20.33 million USD) to improve building efficiency.

4 Tam, S.T. Skyscraper Green Retrofits Guide, 2011. Global Energy Network Institute (GENI). http://www.geni.org/globalenergy/research/skyscraper-green-retrofitsguide/Skyscraper-Green- Retrofits-Guide-FINAL.pdf.

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In accordance of the Better Building Initiative launched by President Barack Obama to make the country’s buildings more energy efficient, a voluntary effort advocating the Atlanta Better Buildings Challenge, Cheryl Strickland, “Invest Atlanta’s managing director of redevelopment” explained this program could give downtown a boost for a strong and competitive central business district is important economically. She also explained: “Until market demand for new commercial building is reestablished, the best way to support economic development of Atlanta’s central business district is to encourage commercial retrofits, renovations and upgrades of the existing building stock” 5. Further, research shows that buildings in the U.S. and Europe that are retrofitted enjoy greater rent values than the ones that are not upgraded.

04.1.2 Evironmental

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Clear environmental benefits provided by Retrofitted buildings through reducing their energy consumptions, lowering demand on the power grid and decreasing greenhouse gas emission. For example, in New York City, 5000 Skyscrapers constitutes almost 80% of the city’s carbon footprint greenhouse gas emission from total of 900,000 buildings. Another example is the Portland City, Research shows if retrofit buildings in Portland or it will likely to be demolished over the next 10 years, “The potential impact reduction would total approximately 231,000 metric tons of CO2—approximately 15% of their county’s total CO2 reduction targets over the next decade” (Frey et. al 2011) 6. It is a mistake to assume the CO2-reduction gained by a new, energy efficient building mitigate any negative climate change impacts associated with the construction of that building. Recent research describe that as it requires “10 to 80 years for a new building that is 30% more efficient than an average-performing existing building to overcome, through efficient operations, the negative climate change impacts related to the construction process”. 7 A study simulates two structures; they were two retail buildings in Atlanta, Georgia with similar life spans of 60 years.

They were also of the same sizes and dimensions which include a gross floor area of 278 square meters and an average height of 4 meters.

5 Wheatley, T. Should the Public Pay to Help Retrofit Downtown’s Skyscrapers and Buildings? Available online: http://clatl.com/freshloaf/archives/2012/04/19/should-the-public-pay-to-help- retrofit-downtowns-skyscrapers-and-buildings 6 Wheatley, T. Should the Public Pay to Help Retrofit Downtown’s Skyscrapers and Buildings? Available online: http://clatl.com/freshloaf/archives/2012/04/19/should-the-public-pay-to-help- retrofit-downtowns-skyscrapers-and-buildings 7 Samuel, S.; Mehtab, N. Revisiting the Case of Sustainable Construction via LCA—Build New or Reuse?; SERF Foundation: Michigan, MI, USA, 2014.

Fig:4.1 Global Warming Potential of New and Existing Building (Sources:Kheir Al-Kodmany, 2014 Green Retrofitting Skyscrapers: A Review P.01)

A lot of researches claims that reuse and retrofitting for buildings offer the most significant climate change emissions reductions, human health, and resource impact. Therefore, building retrofit can help cities to find a way to achieve their short-term carbon reduction goals. In areas of harsh climate, it suggested that reuse and retrofit are particularly impactful, also in the areas uses coal as a dominant energy source, such as the City of Chicago, where coal constitutes 65% of its energy source.

04.1.3 Governmental Overall, some public authorities like governments seeing that the economic and environmental values behind green retrofit for buildings. “Efficiency can save 75% of America’s electricity at lower cost than making it at existing power plants. Helping customers reduce or defer usage when electricity is scarce can also increase distribution equipment’s life and reliability” 8.

For example, the U.S. government encourages green retrofit projects through providing financial incentives like offering tax breaks, credits or grants to. The federal stimulus package alone had green building grants estimated by $4.5 billion. In addition to an energy-efficient federal tax deduction that could total up to $1.80 per square foot for commercial buildings. Two ambitious green programs that encouraged retrofitting is the Energy Efficiency Building Retrofit Program launched in 2007 and 2011by a former U.S. Presidents William Clinton and Barack Obama.

The first program explored ways to make efficiency retrofit projects more bankable with unsubsidized, commercial lending models applicable in a variety of countries. In, the other initiative called “Better Buildings Initiative” aims at making commercial buildings 20% more energy efficient over the next decade by motivating the private sector investment to upgrade buildings.

President Obama stated that improving the energy efficiency of 8 Lovins, A. It’s All about Efficiency. The New York Times, 30 July 2006. Available online: http://www.nytimes.com/2006/07/30/opinion/nyregionopinions/30CIlovins.html?_r=0

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buildings can create jobs, save money, reduce the country’s dependence on foreign oil and make air cleaner.

The German Strategy for Energy-Efficient-Buildings & CO2 -Rehabilitation Program operated by KfW on behalf of Federal Ministry for Economic Affairs and Energy, Germany affording different types of loans and grants to push forward the residential green retrofitting so they can achieve their energy challenge for buildings through the next 4 decades which are by 2020 Heat Demand should be less by 20% compared with 2008 levels also By 2050 Primary Energy Demand for buildings should be less 80% compared with 2008 levels not only but looking forward to let the existing building stock to be “almost climate neutral” (by reducing heat demand and heating based on renewables and Improving the quality of energy-efficient measures.

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Fig:4.2 Energy-Efficient Refurbishment (KfW-Programme) (Sources:German Strategy for Energy-Efficient-Buildings & CO2-Rehabilitation Programme, P.7)

04.1.4 A New Trend Peer pressure has been a driver of skyscrapers’ green retrofitting. For example, the Empire State Building and the Willis Tower as the tallest and most famous skyscrapers in the United Stateshave already embraced green retrofit, other skyscrapers’ owners and investors have been encouraged to follow the trend. Furthermore some agencies and high profile companies consider locating in “green” buildings a priority. For example, in the case of the Empire State Building, after the retrofit announcement, the Federal Deposit Insurance Corporation (FDIC) committed to a major lease. In addition, Skanska USA, the U.S. division of Swedish construction firm Skanska AB reasoned the the major part of their decision to relocate in the Empire State Building are the energy and sustainability factors. “Many high-profile tenants won’t even consider moving into a property without the U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED) certification.

They may not even know what the certification means, but they demand it nonetheless” 9. Four types of tenants are at the forefront in demanding green workplaces: • The Fortune 500 “an annual list compiled and published by Fortune magazine that ranks 500 of the largest multinational corporations by total revenue for their respective fiscal years” with corporate sustainability reports; • The new companies that want to recruit the cutting-edge young talent that sees sustainability as a given, not an add-on; • Government tenants as their own policies require such facilities; • The public sector at large that is increasingly boosting the retrofit of public buildings with energy-efficient features. 10

9 Kahn, K. Iconic Skyscrapers Invigorated by Going Green. USA Today, 4 July 2009. Available online: http://usatoday30.usatoday.com/news/nation/2009-07-04-skyscrapers-green_N. htm 10 Green’ Buildings a Mixed Bag as Budgets Contract. Environmental Leader, 3 August 2009. Available online: http://www.environmentalleader.com/2009/08/03/green-skyscrapers-earn-higher- lease-rates-utility-projects-scale-back/

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04.2 Common efficient key elements for green retrofitting of Skyscrapers facades The sustainable retrofitting design for skyscraper will be more explained in next chapters but generally we should understand first how we can use the skyscraper design elements to be environmentally responsive.

What are the design elements of the skyscrapers which can directly affect energy consumption if it changed or redesigned? And how it can be used in different climatic ranges?

It should be made clear that the above discussion assumes that the former already built skyscraper designer has already carried out the standard built-form and systems studies usual in skyscraper design (e .g. elevator “waiting time and handling capacity” studies, fire-escape route distance calculations, toilet provision calculations and other factors). In the early stages of the retrofitting of the skyscraper’s facade, the new designer evaluates different façade materials and configurations while at the same time keeping in mind the built configuration and massing options of the skyscraper. It is important that at the preliminary stages of redesign. The designer simultaneously takes other considerations into account.

• The position of the service-cores and how this affects the overall building configuration and layout.

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• The orientation of main facades and window openings (especially in relation to the climatic characteristics of the locality) • The façade form and transitional spaces design options • Interactive configuration

external

walls

and

building’s

plan

• The effects and use Vegetation, solar shading, cross ventilation as a passive way to cool buildings •

Thermal mass and thermal insulation walls 11

11 Ken Yeang, Alan Balfour, Ivor Richards, Bioclimatic skyscrapers.

04.2.1 Service core

Fig:4.3 Menara

UMNO in Penang, Malaysia the service core is placed along the southeast façade of the building (Sources:web, Emporis.com)

Fig:4.4 The

Deutsche Messe AG Building in Hannover, Germany, ventilation tower rises by about 30 m above the northern access core (Sources: Herzog, T. (2000) Sustainable Height: Deutsche Messe AG Hannover Administration Building.

Prestel Press: Munich. )

Service core position is of central importance in the design of the tall building. The service core not only structural ramifications, it also affects the thermal performance of the building and its views, and it determines which parts of the peripheral walls will become openings will become openings and which parts will comprise external walls. Core positions can be classified into three types: central core, double core and single-sided core. In the tropics, cores should preferably be located on the hot east and west sides of the building, in Menara UMNO as an office building designed by T.R. Hamzah and Yeang located in the center of Penang, Malaysia which has tropical climate endures consistently hot weather throughout the year, seeing temperatures hover around 31 °C. Occasional rain showers can occur at any time of year, the service core (containing elevator lobbies, staircases, and toilets) is placed along the southeast façade of the building, constituting a thickly buffered party wall that shades the offices from the morning sun (Fig. 4.3). This configuration also allows the public and circulation areas to receive natural light and ventilation, thus reducing the energy needed to operate these spaces. 12 A double core has many benefits. With both cores on the hot sides, they provide buffer zones, insulating internal spaces.

Studies have shown that minimum air-conditioning loads result from using the double –core configuration in which the window openings run north and south, and the cores are placed on the east and west sides, the same considerations apply in temperate zones. 13 Lift lobbies, stairways and toilets should be given natural ventilation and a view out where possible. Inevitably, this means that they should be on the periphery of the useable floor space.

External periphery placement of these parts of the building results in energy savings since they will not require mechanical ventilation and the demand reduced artificial lighting, as well as eliminating the need for additional mechanical pressurization ducts for fire protection. The Deutsche Messe AG Building designed by Herzog + Partner in Hannover, Germany presents a good example of how the access/ service core can be exploited as a ventilation stack in a tall building. The access core transcends its intended function to become a key element of the tower’s ventilation strategy. A ventilation tower rises by about 30 m above the northern access core. The exploitation of thermal uplift is an important aspect of natural air-supply and extracts system for the entire building. 14 12 LH Ismail (2007). An evaluation of bioclimatic high rise office buildings in a tropical climate, Page:03 13 LH Ismail (2007). An evaluation of bioclimatic high rise office buildings in a tropical climate, environmental strategies for building design in tropical climates.

14 Herzog, T. (2000) Sustainable Height: Deutsche Messe AG Hannover Administration Building. Prestel Press: Munich.

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Aesthetically, by placing these service zones on the periphery, they receive sunlight and have views our which are not possible with a central-core position. The user of the building leaving an elevator at an upper floor can see out and be aware of the place instead of entering an artificially lit lobby that could be anywhere in the world.

04.2.2 Building orientation Tall buildings are exposed to the full impact of external temperatures and radiant heat. Accordingly, the overall building orientation has an important bearing on energy conservation.

In general arranging the building with its main and broader openings facing north and south gives the greatest advantages in reducing insulation (and the resulting air-conditioning load). It frequently happens that the geometry of the site does not coincide with sun path geometry. In these cases, the other built elements may, if expedient for planning purposes, follow the site geometry (for example, to optimize basement car-parking layouts). Typical floor window openings should generally face the direction of least insolation (north and south in the tropics). Corner-shading adjustments or shaping may need to be done for sites further north or south of the tropics or for non-conformity of the building plan to the solar path. 15

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Generally, window openings should orientate north and south unless important views require other orientations. If required for aesthetic reasons, curtain walling may be used on non-solar-facing facades. On other faces of the building some form of solar shading is required, while the quality of light entering spaces should also be considered.

The careful orientation of a tall building in relation to the prevailing wind and sun significantly improves the prospects of natural ventilation. Manitoba Hydro Place in Winnipeg, Canada is a prime example of how the building forms and massing responds to both solar orientation and the prevailing wind direction. The building opens up toward the south, revealing a series of sky gardens which capture both Winnipeg’s abundant sunlight and its consistent southerly winds. This orientation improves the effectiveness of natural ventilation and preheats the incoming fresh air, ideal for natural ventilation in cold climates. 16 15 N.A.Naamandadin, A. Sapian, S.N.A.M.Noor, (2016) Site Planning and Orientation for Energy Efficiency: A Comparative Analysis on Three Office Buildings in Kuala Lumpur to Determine a Location for Building Shading Device 16 Wood, A. (ed.) (2010) Best Tall Buildings 2009: CTBUH International Award Winning Projects. Routledge: New York, pp. 20–27.

Fig:4.5 Manitoba

Hydro Place in Manitoba Canada, is a prime example of how a tall building’s orientation respond to both prevailing solar and wind (Sources:Kuwabara, B., Auer, T., Gouldsborough, T., Akerstream, T. & Klym, G. (2009) “Manitoba Hydro Place: integrated design process exemplar,” in Demers, C. & Potvin, A. (eds.) Proceedings of PLEA 26th International Conference. Les Presses de l’Université Laval: Quebec City, pp. 551–556)

Consideration should also be given to the primary driving forces which induce airflow in and out of the building. Although the predominant forces for naturally ventilating a tall building are likely to be bouyancy-induced, if wind (cross-ventilation) is the primary driving force, it is important to orient the main windward openings in the direction of the prevailing wind, as in the case of the San Francisco Federal Building. When there is little wind or the building openings are not able to be oriented in the direction of the prevailing wind, aerodynamic elements such as the use of wind Wing Walls in Menara UMNO, Penang, Malaysia, can be utilized to capture the wind through a wider incident angle and induce more effective natural ventilation. 17

Fig:4.6 Wing Walls on the southwest in Menara UMNO, Penang, Malaysia.

(Sources:Powell, R. (1998) “Vertical aspirations– Menara UMNO: Penang, Malaysia; architects: T. R. Hamzah & Yeang,” Singapore Architect, vol. 200, pp. 66–71) 17 Jones, P. J. & Yeang, K. (1999) “The use of the wind wing-wall as a device for low-energy passive comfort cooling in a high-rise tower in the warm mid tropics,” paper presented at PLEA 16th International Conference, Brisbane, Australia, 22–24 September.

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Furthermore, a circular tower allows for better wind-induced ventilation from various directions. Conversely, when both wind and buoyancy driving forces are employed simultaneously, there is greater flexibility with building orientation with regard to the prevailing wind direction. For example, the main windward openings in GSW Headquarters in Berlin are located on the east side despite the wind predominately blowing from the west. GSW building’s orientation is based on the sun path and its relation to the thermal flue (west-facing space) which utilizes stack effect induced by the afternoon sun. In this case, stack effect and solar heat gain create buoyancy-induced cross-ventilation and maintain sufficient airflow rates and comfort levels, even on hot days in the absence of wind. Strong winds from a predominant direction can thus be exploited to allow for single-sided and/or double-sided cross ventilation. 18

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Fig:4.7 View

into the west façade which doubles as a thermal flue in the GSW Headquarters building in Berlin (Sources: © Annette Kisling)

KfW Westarkade designed by Sauerbruch Hutton in Frankfurt benefits from an average wind speed of four meters per second, which comes from the southwesterly direction for approximately 50 percent of the year. The building’s directional, aerodynamic form and orientation allows fresh air to enter the exterior ventilation flaps of the double-skin façade.

When using wind-driven natural ventilation, especially in tall buildings, the risk of excessively high winds at height needs 18 Sauerbruch, M. & Hutton, L. (eds.) (2000) GSW Headquarters, Berlin. Sauerbruch Hutton Architects. Lars Müller Publishers: Baden.

to be evaluated and mitigated. The prospects of a purely naturally ventilated building are significantly enhanced when the two driving forces, wind and buoyancy, act in unison. For tall buildings to rely exclusively on natural ventilation, an inward flow of air must be maintained even when winds are weak, there is no wind, or the wind is not blowing from the desired direction.

With little or no wind, buoyancy-induced ventilation can provide an alternative/additional driving force to ensure the effectiveness of natural ventilation. 19

Fig:4.8 KfW

Westarkade plan showing the building’s directional, aerodynamic form and orientation allows fresh air to enter the exterior ventilation flaps of the double-skin façade so the offices are ventilated directly through this double-skin façade system (Sources: Antony Wood & Ruba Salib, 2013, Natural Ventilation in High-Rise Office Buildings ,P 124)

Additionally, It should be noted that using heat-recovery equipment can impede the flow and reduce flow volumes. One such solution is to have two exhaust routes for the flue: one in winter that passes through heat-recovery equipment when less natural ventilation air is necessary, and a second for summer without heat-recovery for when it is not necessary but higher airflow rates are essential.

19 Gonchar, J. (2010) “More than skin deep,” Architectural Record, vol. 198, no. 7, pp. 102– 110.

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04.2.3 The façade treatment, double skin and transitional spaces design options Most of global commercial skyscrapers using curtain walls as an external shell for the building’s skeleton which leads to let the interior spaces are more exposed to the external environment and weather elements. So any change in the façade form and materials are affecting directly the indoor occupant comfort in case of thermal, visual and acoustic comfort.

In addition, there is much room for improvement in basic curtain-wall technology so curtain-wall retrofits are always a cheaper and optimal solution to provide the optimal façade performance from an energy efficiency standpoint.

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This is because the curtain-walls are characterized by different elements that are not good insulation from the external elements like the overuse of vision glass as a matter of preference over opaque panel solutions that can provide improved insulation. Even with highly insulated panels, the metal framing of a curtain-wall system, typically of aluminum, is highly conductive and can easily compromise thermal performance. Thermal breaks add to the system cost but are required to optimize energy efficiency. Air infiltration is also a common problem. The industry is responding to the increasing performance demands through the different elements as explained in (Fig:4.9) , developing the industry of glazing, internal lighting fixtures control, curtain wall stack joint detail, solar shading and building management system that working on managing and control all of these elements so they can work together to enhance their performance so significant development is required before curtain-wall technology is available to support sustainability goals. 20 The Highlight Towers, Munich have a single-skin façade and are naturally ventilated through pivoting panels integrated in the façade. Fixed, triple-glazed windows feature high-performance and heat-reflecting properties while a narrow, operable glass panel enables direct natural ventilation. A perforated, stainless steel panel (with soundproofing properties) is mounted behind the pivoting panel to provide protection against the sun, wind, and rain. 21

20 Mic Patterson, 2013, Incremental façade retrofits: Curtainwall technology as a strategy to step existing buildings toward zero net energy P. 05 21 Schmidt, C. (2006) Highlight Towers. Braun Publishing: Berlin.

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Fig:4.9 Design

considerations for optimal faรงade efficiency include advanced glazing materials, daylighting design, shading systems, super insulating materials like vacuum insulated panels, and building integrated photovoltaic technology.

(Sources: Mic Patterson, 2013, Incremental faรงade retrofits: Curtainwall technology as a strategy to step existing buildings toward zero net energy P. 05)

Fig:4.10 Single-skin

façade of Highlight Towers in Munich is ventilated through operable panels behind perforated, fixed steel panels.

(Sources: © Murphy/Jahn Architects)

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In a double-skin façade, the outer glazing layer provides additional protection against weather conditions and external noise (both urban level and wind induced) and allows greater control of incident wind speeds, therefore enhancing the prospect for natural ventilation in high-rise buildings. Additionally, a double-skin façade acts as a thermal buffer, mediating temperatures between the interior and exterior. During the heating season, solar gain in the cavity of the double-skin can serve to preheat fresh air before it enters the building.

Conversely, during the cooling season, the cavity is ventilated in order to carry away solar heat gain. A double-skin façade also allows for the integration (and protection) of shading device within the cavity, which provides an added benefit of reflecting solar heat gain before it enters the building. The ventilated cavity can thus exhaust the solar heat in the cavity before it has the opportunity to penetrate the inner façade layer and inhabited spaces beyond. 22 Careful consideration should be given to the design of a double-skin façade. If the cavity is not sufficiently ventilated and/or sunshading devices are not properly positioned, the façade could experience overheating in the summer.

Furthermore, double-skin façade design requires specific considerations for the position and sizing of openings to en22 A. Wood, R. Salib, 2013, Guide to Natural Ventilation in High Rise Office Buildings Page: 152

Fig:4.11 View

into the 1.4-meter-deep double-skin façade of Deutsche Messe AG Building.

(Sources: © MoritzKorn)

sure proper pressure distribution within the natural ventilation system. High-rise buildings experience significantly different wind speeds and pressures differentials at various heights and locations across the façade, and the double-skin openings need to somehow account for these. For example the Fish Mouth device in the double-skin façade of RWE Headquarters Tower in Essen, Germany changes in size above floor 16 to moderate wind pressures across the envelope openings.

At KfW Westarkade, Frankfurt, the sophisticated BMS system controls the double-skin façade to act as a complete “Pressure Ring” altering the degree of openness of exterior ventilation flaps to control and maintain the pressure differentials across the façade. 23

Prevailing winds

Pressure distribution

Fig:4.12 Diagrams of the Pressure (Sources: © Sauerbruch Hutton)

Through-flow

Ring façade in KfW Westarkade, Frankfurt.

23 Gonchar, J. (2010) “More than skin deep,” Architectural Record, vol. 198, no. 7, pp. 102– 110.

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It should be noted, however, that no two buildings employ the same solution for the double-skin/natural ventilation strategy. Even the depth of the cavity differs significantly across as shown in the following figure different double-skin cavities, from 200 to 1,700 mm, with some buildings having varying cavity depths across the differing faces of the same building.24

Fig:4.13 A

comparison of double-skin façades of diffrent case study buildings in this Technical Guide.

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(Sources: Antony Wood & Ruba Salib, 2013, Natural Ventilation in High-Rise Office Buildings ,P 152)

Although there seems to be good consensus that double-skin façades have a potentially positive role to play in the natural ventilation of tall office buildings, especially in more temperate climates, there is not yet consensus on what detailed form the double-skin should take. All the offset factors also need to be taken into account – such as increased material and construction costs or loss of floor space. Perhaps this is why the strategy has yet to gain any traction in the more commercially orientated US building industry.

04.2.4 Transitional spaces In temperate zones, transitional spaces can have adjustable glazing at the other face so that balconies or recesses can act as ‘sun spaces’, collecting solar heat, like a greenhouse or conservatory.

24 A. Wood, R. Salib, 2013, Guide to Natural Ventilation in High Rise Office Buildings Page: 152

Deep recesses may provide shade on the building’s hot sides. A window can be totally recessed to form a balcony or a small sky court that can serve a number of functions besides shading. Placing balconies on hot elevations permits glazing to these areas to be full-height clear panels. These can give access to the balcony spaces which can serve as evacuation spaces, as large spaces which can serve as evacuation spaces, as large terraces for planting and landscaping, and as flexible zones for the addition of future facilities.

In Menara UMNO Penang, Malaysia three different techniques were used to minimize solar heat gains while retaining sufficient daylight and reasonable views. One of these design techniques is the glazed northwest and southwest façades are protected from afternoon sun by sky court balconies and perforated, horizontal aluminum screens acting as solar shading devices. The screens are deeper and more opaque toward the west and more transparent toward the north. 25

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A B Fig:4.14

A. View for the west elevation B.View from one of the balconies.

(Sources: © T.R. Hamzah and Yeang) 25 Jahnkassim, P. S. & Ip, K. (2000) “Energy and occupant impacts of bioclimatic high-rises in a tropical climate,” in Steemers, K. & Yannas, S. (eds.) Proceedings of PLEA 17th International Conference. James and James (Science Publishers) Ltd.: London, pp. 249–250.

Large multi-story transitional spaces might be introduced in the central and peripheral parts of the building as air spaces and atriums. These serve as in-between zones located between the interior and the exterior. They should function like the verandah ways of the old shop-houses or the porches of early nineteenth century masonry houses of the tropics.

Atriums should not be totally enclosed but should be placed in this in-between space. Their tops could be shielded by a louvered roof of encourage wind-flow through the inner areas of the building. These may also be designed to function as wind scoops to control natural ventilation to the inner parts of the building. 26

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A B Fig:4.15

A. Internal view of a six-story atrium in 30 St. Mary Axe London, UK – looking downwards onto the social meeting space at its base B. Section showing wind-flow through the inner areas of the building (Sources: Š Nigel Young / Foster + Partners)

26 Ken Yeang, 1987, Tropical Urban Regionalism, Building In A South East Asian City Page: 77

After the decision to naturally ventilate tall buildings is made, the façades need to be carefully designed to respond to the specifics of air speed, urban noise, noise generated by air movement, and solar protection, among other things. There has been a tendency in recent years – especially in Europe – toward employing double-skin façades to assist with natural ventilation. There are numerous benefits of such twin-layer envelopes, however, selecting the appropriate glazing is crucial to getting the necessary performance.

04.2.5 Interactive external walls External walls should be regarded as permeable, environmentally interactive membranes with adjustable openings (rather than as a sealed skin). In temperate climates the external wall has to serve very cold winters and hot summers. In this case, the external wall should be filter-like, with variable parts that provide good insulation but are open able in warm periods. In the tropics the external wall should have moveable parts that control and enable good cross-ventilation for internal comfort, provide solar protection; regulate wind-driven rain, besides facilitating rapid discharge of heavy rainfall.

Fig:4.16 Opening

of the entire façade of of KfW Westarkade at the “tip” to enable through-flow of air on hot summer days.

(Sources: © Jan Bitter)

For example the external walls of KfW Westarkade, Frankfurt, can be fully opened in the summer to avoid overheating, and minimally opened in the winter to allow the double-skin façade to function as a solar collector. To prevent overheating on hot summer days, the entire façade (including the wider window panels which are typically fixed) at the “tip” of the building can be opened to enable through-flow of air (Fig:4.16). Throughout the entire year, the BMS will advise occupants whether or not to open their windows through an LED panel in offices, but it gives the occupant the final choice. 27 04.2.6 Building’s plan configuration The planning and spatial configuration of a tall building largely determines the possibility and effectiveness of design solution for occupant comfort. Cellular offices can benefit from stack effect in an adjoining atrium while an open-plan office may be more conducive to cross-ventilation. Additionally, the floor-toceiling height can have a major impact on the natural ventilation effectiveness. The British Council of Offices Guide recommends a minimum floor-to-ceiling height of three meters (2.7 meters is closer to the standard) to enable more airflow through 27 Gonchar, J. (2010) “More than skin deep,” Architectural Record, vol. 198, no. 7, pp. 102– 110.

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the interior space (Gonçalves 2010) 28. With the removal of a centralized mechanical system and the utilization of a decentralized mixed-mode system, Post Tower, Bonn, Germany operates without the necessity of multiple mechanical floors.

In doing so, floor-to-ceiling height increases while the floor-tofloor height decreases compared to a traditional system with dropped ceilings and ducts 29.

Typical office space in the Post Tower in Bonn, Germany, which enjoys high floor-to-ceiling heights due to its decentralized mechanical system.

Fig:4.17

112

(Sources: © Murphy/Jahn Architects)

Some high-rise buildings in this study also demonstrate that the implementation of natural ventilation can require a radical change in the interior layout from that of a conventional tall office building (which typically sees cellular offices along the perimeter and open-plan office spaces at the center). The open-plan office spaces of both Manitoba Hydro Place, Winnipeg and the San Francisco Federal Building (Fig:4.18) are located at the periphery of the building, with the conference rooms, private meeting spaces and cellular offices located toward the center of the floor plate . Both scenarios utilize low partition walls in the open-plan offices and gaps between enclosed rooms and the ceilings to permit airflow from one side of the office space to the other with minimal obstructions. Conversely Post Tower in Bonn, Germany (Fig:4.19) has located its cellular office on the perimeter of the building 28 BCO (2014) BCO Guide to Specification. Lonodn, The British Council for Offices.

29 Eisele, J. & Kloft, E. (2003) High-rise Manual: Typology and Design, Construction and Technology. Birkhauser: Basel, pp. 186–188.

30 A. Wood, R. Salib, 2013, Guide to Natural Ventilation in High Rise Office Buildings Page: 149

in a traditional fashion, but utilizes “loose fittings� at the glass partitions to allow air to flow through the offices to the corridor beyond. 30 A

B

Showing the spatial configurations of openplan office spaces along the perimeter and cellular offices at the center.

A. Floor plan of Manitoba Hydro Place, Winnipeg B. Floor plan of San Francisco Federal Building Fig:4.18

(Sources: Antony Wood & Ruba Salib, 2013, Natural Ventilation in High-Rise Office Buildings ,P 114, P106)

Showing the spatial configurations of Cellular office spaces along the perimeter and open-plan office spaces at the center in the floor plan of Post Tower in Bonn, Germany Fig:4.19

(Sources: Antony Wood & Ruba Salib, 2013, Natural Ventilation in HighRise Office Buildings ,P 76)

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The ground floor in the tropics should preferably be open to the outside and naturally ventilated. The relationship of the ground floor to the street is also important. The introduction of the indoor atrium at the ground floor may mean the demise of street life. Free standing fortress-like buildings also tend to separate the building from the pavement, further alienating the street.

04.2.7 Vegetation, solar shading, cross ventilation as a passive way to cool buildings Free-standing buildings become isolated on their plots.

Planting and landscaping should be used not only for their ecological and aesthetic benefits, but also to cool buildings.

Planting should be introduced as vertical landscaping to faces and inner courts of upper parts of tall buildings. Plants absorb carbon dioxide and generate oxygen, benefiting the building and its surroundings.

The use of sky gardens in the design of naturally ventilated tall buildings has now become quite common. From a natural ventilation standpoint, the sky gardens can be used for air intake, air extraction, a combination of the two, or to induce ventilation in inward-facing offices, as is the case at Commerzbank, Frankfurt (Fig:4.21). In this building, a central atrium coupled with the radial arrangement of offices and sky gardens has provided great flexibility in ventilating the building, irrespective of prevailing winds. 31 114

Floor plan and Section view for Commerzbank Frankfurt, Germany showing sky gardens can be used for a combination of air intake, extraction and induce ventilation in inward-facing offices.

Fig:4.21

(Sources: Antony Wood & Ruba Salib, 2013, Natural Ventilation in High-Rise Office Buildings ,P 134) 31 Fischer, V. (1997) Sir Norman Foster and Partners: Commerzbank, Frankfurt am Main.

Axel Menges: Stuttgart

Section view into 1 Bligh Street, Sydney showing the open ground floor to the outside and how it is naturally ventilated Fig:4.20

(Sources: Antony Wood & Ruba Salib, 2013, Natural Ventilation in HighRise Office Buildings ,P 134)

In most scenarios, sky gardens are used as extraction chimneys which exhaust air from the building through stack effect. In Manitoba Hydro Place, however, south-facing winter gardens provide air intake and pre-heat incoming cold air during the heating season. This building also has north-facing atria that exhaust stale air from the office spaces into the solar chimney.32

South atrium showing the sky garden as a six story-tall atria act at the building’s lungs drawing fresh air in and precondition it before inletting fresh air through the opaque spandrel panels on the inner façade to the under-floor distribution to the offices. “Manitoba Hydro Place, Canada” Fig:4.22

(Sources: © KPMB Architects/Eduard Hueber)

In all cases, sky gardens function as buffer zones which mediate the temperatures between exterior and interior. When they are located at the exterior of the building and used as air intakes, although the scale of the spaces and environmental configurations are obviously much different, they conceptually offer some of the same benefits presented by double-skin glass façades, such as thermal insulation and protection against undesirable weather conditions, noise, and high wind speeds.

In addition to bringing daylight deeper into the building plan and assisting natural ventilation, sky gardens also allow visual, social, and physical connectivity as a destination and transition space within a tall building.

One can argue that, with increasing inner-city densification, population increases, and the consequent loss of open spaces (the public realm) at the ground level, tall buildings will increasingly require communal sky gardens as part of a more 32 Sampson, P. (2010) “Climate-controlled,” Canadian Architect, vol. 55, no. 1, pp. 16–22.

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“public” program in the sky. As a destination space, sky gardens provide a hospitable environment for social interaction and recreation. As a transition space, sky gardens function like sky lobbies, providing ease of movement and allowing occupants to orient themselves within the building and urban context (Pomeroy 2008). 33

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Solar shading devices that maintain good daylight penetration quality are highly important since high solar heat gain can overwhelm a natural ventilation system. Contrarily, in the warming season, a building can benefit from passive solar heat gain to preheat incoming air. An adaptable strategy should be put in place to limit solar heat gain when necessary, allow for solar gain when beneficial, and always reduce glare from occupants’ work spaces. Further, the optimization of daylight can minimize the dependence on artificial lighting, which contributes significantly to energy consumption in the building (typically 30 percent or more of the total building energy consumption as explained in chapter 01) and also adds significantly to internal heat gains. 34 Torre Cube, Guadalajara uses a simple, wooden lattice brise-soleil (Fig:4.23) that can be manually operated by the individual occupants to give shade and control solar gain In hot climates, the brise-soleil screen to protect again high wind speeds, wind-driven rain, and solar heat gain. Since this lattice screen is open on all sides, air can pass through the interstitial space, mitigating the risk of excessive heat buildup and allowing convective cooling on the glass façade 35 A

B

A.View of an interior office space, showing sliding windows with the wooden brise-soleil beyond in Torre Cube Guadalajara, Mexico.

B. Detailed façade section through the wooden brise-soleil Fig:4.23

(Sources: © Estudio Carme Pinós / Lourdes Grobet)

33 J. Pomeroy, (2008) Sky courts as transitional spaces: Using space syntax as a predictive theory 34 A. Wood, R. Salib, 2013, Guide to Natural Ventilation in High Rise Office Buildings Page: 154

RWE Headquarters Tower in Essen, Germany boasts the use of clear glass by incorporating perforated blinds within the double-skin cavity, and an alternate interior anti-glare screen (Fig:4.24).

A

B

A. View looking up at the RWE Tower in Essen, Germany with its ultra-clear glass façade.

B. Interior view showing perforated aluminum blinds in the façade cavity Fig:4.24

(Sources: © ingenhoven architects )

Cross-ventilation should be used (even in air-conditioned spaces, to cope with system breakdowns), letting fresh air in and exhausting hot room air. Good air movement promotes heat emission from the human body surface and gives a feeling of comfort. Skycourts, balconies, and atriums as open spaces and transitional spaces at the upper parts of the tall building encourage wind flow into internal spaces. Side vents operating as wind scoops located at the edges of the facade capture wind and make the best use of the high wind speeds found at upper levels. Wind can be channeled into ceiling plenums to ventilate inner spaces. 36 The driving forces for natural ventilation in a tall building are of course the same as those for other buildings. The physical mechanisms for natural ventilation rely on the pressure differences generated across the envelope openings of a building.

35 Schittich, C. (ed.) (2007) “Torre Cube in Guadalajara, Mexico,” Detail, vol. 47, no. 9, pp.

962–964, 1076.

36 Per Heiselberg, 2006, Design of Natural and Hybrid Ventilation Page: 49

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The pressure differences are generated by: (i) The effects of wind, (ii) Temperature differences (gravity acting on density) between inlet and outlet of air, or (iii) A combination of both.

Natural ventilation can therefore be categorized into “Wind-induced” and “buoyancy-induced” ventilation according to the physical mechanism driving the air. Wind-induced ventilation occurs when wind creates a pressure distribution around a building with respect to the atmospheric pressure.

The pressure differences drive air into the building’s envelope on the windward side (positive pressure zone) and out of the building through the openings on the leeward side (negative pressure zone). The pressure effect of the wind on a building is primarily dominated by the building’s shape, the wind direction and velocity, and the influence of the surroundings, which are all factors that influence the pressure coefficient.

In addition to the value of the pressure coefficient, the mean pressure difference across a building’s envelope is dependent upon the mean wind velocity at upwind building height, and the indoor air density as a function of atmospheric pressure, temperature, and humidity. Buoyancy-induced ventilation (also known as “stack effect” or the “chimney effect”) occurs due to density differences caused by variations in temperature and height between the inside and the outside or between certain zones within a building. 37 118

A B Fig:4.25 A. Study on the Section of Liberty Tower of Meiji University Tokyo, Japan showing the stack effect in the central escalator void (the “Wind Core”) pulls air from the classrooms at each floor.

B. Study on the floor plan showing cross ventilation using Wind-induced (Sources: Antony Wood & Ruba Salib, 2013, Natural Ventilation in High-Rise Office Buildings ,P 44 ) 37 A. Wood, R. Salib, 2013, Guide to Natural Ventilation in High Rise Office Buildings Page: 18

04.2.8 Thermal mass and thermal insulation walls Good thermal insulation of the building skin reduces heat transfer, both from solar gain and loss of coolness from the inside. A second skin (a rain wall) can be built over the inner wall with an air gap in between. Structural building mass may be used to store heat. The mass loses heat during the night and keeps internal spaces cool during the day. In temperate climates, structural and building mass can absorb solar heat during the day and release it at night. A water-spray system on hot facades promotes evaporation and therefore cooling.

In temperate climates, solar windows or a solar-collector wall can be located on the outer face of the building to collect the sun’s heat. 38

In the interior of San Francisco Federal Building San Francisco, Wave-form exposed concrete soffits to increase surface area of the thermal mass.

Fig:4.26

(Sources: Š Nic Lehoux)

38 Yeang, K. (1994) Bioclimatic Skyscrapers. Artemis, London.

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04.3 Green retrofitted Skyscrapers Case Studies The case studies have been selected to cover a variety of climate and socio-economic regions to highlight the practical potential, opportunities and barriers of energy efficient highrise refurbishment.

04.3.1 Empire State Building, “The Green Empire”, New York, NY, USA The Empire State Building is located in Midtown Manhattan, New York City. As a 102-story, 381 m, the skyscraper construction was completed in 1931 to be the tallest building in the U.S. for almost four decades, until the World Trade Center’s North Tower in late 1970. With its beautiful Art Deco Style, elegant profile, and distinctive height and history, the building enjoys an important place in the American culture as a symbol of the power of New York. It was named as one of the Seven Wonders of the Modern World by the American Society of Civil Engineers. A wide-range of businesses is attracted to this building which contains 260,128 m2 of office space; it’s one of the icons of Manhattan’s center skylines.

The 86th floor attracts around 4 million visitors yearly just to visit its observatory. Before the Empire State Building for long represented a symbol of power of the New York City but now become also a symbol of “green power efficiencies”, or as nicknamed “the Green Empire”. 39 120

In 2009 the green retrofit project began as part of the “Clinton Global Initiative” as explained before in retrofitting drivers and over half billion dollar retrofit started in 2010 for that 80-years old building, with to transform the building to be more energy efficient and eco-friendly structure. This building upgrade is the largest retrofit of its kind to date in the United States. “It is designed to reduce energy use by 38% which is more than $4.4 million annually, cut carbon emissions by 105,000 metric tons (same produced by 5000 houses annually) over a 15-year period and provide a payback in slightly more than three years”.40 Reducing the building’s carbon footprint by 105,000 metric tons is equivalent to removing 20,000 cars off the road. In terms of economic feasibility, the expected income stream enhancements included 41: •

Decreasing capital improvement program costs;

39 Lehner, P. Empire State Building Cuts Energy Waste, Becomes Unexpected Model of Efficiency, 2012. Available online: http://switchboard.nrdc.org/blogs/plehner/empire_ state_building_cuts_ ene.html 40 GreenBiz.com. Empire State Building Retrofit Lights the Way for New Projects, 2013.

Available online: http://www.greenbiz.com/blog/2013/06/29/empire-state-building-retrofit-new-projects

A model for optimizing energy efficiency, sustainable practices, operating expenses and long-term value in existing buildings Fig:4.27

(Sources: A landmark sustainability program for the Empire State Building report P.1)

• Decreasing utilities bills budget because of higher efficiencies in using water and energy facilities; • Due to lower maintenance and repair costs the building decrease the operations budget; • The building are more attractive for higher quality tenants which leads to increase rent and occupancy due to providing higher quality spaces of greater services and amenities.

One of the important goals of this project was changing buildings owners’ perception of retrofits as an expense, rather than an opportunity for economic gain. “The $550 million Empire State Rebuilding program involved development of a groundbreaking transparent, well-documented, replicable energy-efficiency retrofit program that is broadly applicable to all office buildings” (Lockwood, C. 2014). 42 The project team has pursued a systematic multi-phase analytical process, and conducted comprehensive analyses to determine which energy and sustainability strategies could be implemented at the building and to identify the associated costs, risks and obstacles that might arise for each strategy. Specifically, the project team examined the building’s mechanical systems and equipment, computed tenants’ energy consumption, and developed a baseline energy benchmark report and a system for gaging energy efficiency.

The team stated in their final report (A landmark sustainability program for the Empire State Building): “It is cost-prohibitive to achieving an energy reduction greater than 38%. Their analysis had examined strategies that could have reduced emissions by nearly 45%, out of a theoretical maximum of 55%. A total of 40 energy efficiency ideas were narrowed down to 17 implementable strategies that were later analyzed in depth. Of these, the first 90% of reduced carbon dioxide would also save costs over time by an average $200 per ton of carbon saved. The last 10%, by contrast, would carry a life cycle cost of more than $300 per ton of carbon saved” 41 (Fig:4.28).

It was not only reducing energy and carbon dioxide emissions, but the sustainability program looked forward to deliver an enhanced work environment for tenants including several sustainable aspects similar as the green design goals that have been elaborated previously in chapter 41 A Landmark Sustainability Program for the Empire State Building. Available online: http:// www.institutebe.com/InstituteBE/media/Library/Resources/Existing%20Building%20Retro fits/ESB-White-Paper.pdf 42 Lockwood, C. Building Retro. Urban Land, November/December 2009. Available online: https://www.esbnyc.com/documents/sustainability/uli_building_retro_fits.pdf, p. 56

121

Cumulative metric tons of CO2saved over 15 years Net present value of package of measures Fig:4.28

(Sources: A landmark sustainability program for the Empire State Building report P.9)

03: improving air quality using tenant demand controlled ventilation, better lighting conditions through coordination between ambient and task lighting; and improved thermal comfort resulting from better windows insulation and coating, the radiator barrier and better controls (Fig:4.29). Regarding the energy efficiency the upgrade resulted in significant savings are elaborated in (Fig:4.30 & Fig:4.31). 43 122

Empire State Building (ESB) Performance Year 2. Reduction in ESB’s 2007 Baseline, Electric Utility Costs during Performance Period.

Fig:4.30

(Sources:Graph redrawn from Empire State Building, Performance Year 2 M&V Report 2013 P.15)

Fig:4.31 Empire

State Building Performance Year 2.

Reduction in ESB’s 2007 Baseline, Steam Utility Costs during Performance Period (Sources:Graph redrawn from Empire State Building, Performance Year 2 M&V Report 2013 P.15) 43 Johnson Control. Empire State Building, Performance Year 2 M&V Report, 2013.

Available online: http://www.esbnyc.com/documents/press_releases/2013_ESB_Y2_ Full_Report.pdf

123

Fig:4.29 Summary of key upgraded features of the Empire State (Sources:Kheir Al-Kodmany, 2014, Green Retrofitting Skyscrapers: A Review P.14)

Building

Windows and elevators were the most noteworthy retrofit items among the others. It was unknown before that a skyscraper of this scale can reuses, and not replaces; about 96% of its window glasses have been reused. The building’s owner saved $2300 per window and avoids the negative environmental, ecological and cost impact of transporting new windows from the manufacturing plant and the old ones to recy-

cling factories. In addition that the window retrofit happened without disturbing tenants, the windows were removed and re-installed in the time between after office hours and before most tenants returned to work the next morning. The retrofit crew was 35 working in two shifts, refurbishing 75 to 80 windows in a specific workroom.44 The work process in each night was that, first workers unscrewed windows from their frames, then wheeled them to the workroom, after that they cleaned glass panes after detaching them from their sashes. Later, they laid a sheath of transparent insulation film in the cavity between the glass panes, which were resealed and placed for an hour in a 205-degree oven to shrink the film tightly in place. Before the finish, they pumped a mixture of inert gases into cavity for insulation. Finally, they put the panes back in the original sashes, wheeled them back to offices were they were taken from, and remounted them in the window frames from which they were removed.

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Fig:4.32 Empire State Building windows refurbishment (Sources:Redraw in http://blog.lightopiaonline.com,2012)

The new system saves energy in multiple ways through upgrading the elevator system. The employed regenerative system using braking to harvest waste energy. The machine of conventional elevator can lose from its energy more than 30 percent in the form of waste heat, and the new retrofit reduced the loss to only five percent. The new system for elevators converts the rest of energy into the building’s electrical system. As a direct result from the previous retrofit the sec44 Hampson, R. Empire State Building Goes Green, One Window at A Time. USA Today, 12 July 2010. Available online: http://usatoday30.usatoday.com/news/nation/environment/2010-07-12- empire-state-building-windows-green_N.htm 45 Johnson Control. Empire State Building, Performance Year 2 M&V Report, 2013.

Available online: http://www.esbnyc.com/documents/press_releases/2013_ESB_Y2_ Full_Report.pdf

process

ond saving way has been channeled as the following: in a conventional elevator system, waste heat gathers in the machine room needs substantial air conditioning to prevent overheating.

But the retrofitted system does not have this problem because heat has already been channeled to the electrical system as “surplus” power. “The trick behind the system is a gearless technology based around a permanent magnet AC motor. A gearless machine operating at less than 240 rpm can reach the same speed as a geared machine at 1800 rpm” [Casey, T 2012] 45. The new system’s motor added to the savings by having consumes zero energy when the elevator is not in use.

Finally, high efficiency LED lighting has been accommodated in the cabs of the new elevator system. Collectively, the new elevator system results in significant savings that reduce demand on the city power grid.

Further, which is bit far from retrofitting but as an environmental policy the building’s owners signed an agreement with Green Mountain Energy to purchase 100% of its power from renewable sources, resulting in a positive ecological impact. “By purchasing nearly 55 million kilowatt hours of renewable energy each year, nearly 100 million pounds of carbon dioxide will be avoided annually. In New York City terms, that is equivalent to having nearly every house in New York State turning off all their lights for a week, taking approximately 40 million fewer cab rides or planting more than six times the current number of trees in Central Park” [DeFreitas, S.2011] 46. One of the important aspect that during the retrofit project, the Empire State Building team engaged tenants in planning discussions and enlightened them about retrofit options to create energy-efficient office spaces that they like and enjoy to face one of the important challenges the retrofit initiators facing it which the cost interest between the owner and tenants are different. For example, one of the tenants installed an under-floor ventilation system to bring in fresh air that allowed individual temperature controls for workspaces and designed an open office floor plan to maximize natural light. Incorporating measures like these at the early stages of the retrofit project added only marginal costs that will likely to be recouped in less than five years and fix the problem of the different interests.47 In addition to engaging tenants, a wide range of coordination and integration between different project teams helped the retrofit project such as the capital and sustainability teams facilitated a whole-building retrofit approach. For example, in the 46 Casey, T. “Pimp My Elevator” Retrofit Turns Clunkers into Energy Savers. Clean Technica, 19 February 2012. Available online: http://cleantechnica.com/2012/02/19/thyssenkrupp-eleveator- retrofit-harvest-energy-from-braking/ 47 DeFreitas, S. Empire State Goes Big for Energy. EarthTechling, 8 February 2011. Available online: http://earthtechling.com/2011/02/empire-state-goes-big-for-green-energy/

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begging, the capital team put a budget to replace the chiller plant. However, the sustainability team based on a study found out that chiller replacement could be avoided by retrofitting windows on site, and by just upgrading the existing chiller. Chiller upgrade is far less expensive than replacing it, so such a decision was a significant saving. The planning and design team also employed energy analyses using a building energy simulation tool called DOE-2.2 (eQUEST interface), that allows for comparing sustainable design alternatives.48 It works in the same way of the other energy simulators by inputting various parameters including weather data, building geometry, material properties, equipment schedules, system components and the like, the software program estimated for various design alternatives their energy savings and for every individual choices. Once preliminary energy saving estimates for individual measures were provided, the team used the financial model developed for this project to identify the most cost-effective, ways to save energy. Iterations between these models helped the Empire state building team to figure out the optimal recommendations.

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As a project follow the green standards, the green retrofit of the Building attained the LEED® EBOM (Existing Buildings: Operations and Maintenance) Gold Certification to the entire structure as an existing building, specific spaces within the building received LEED-Platinum certification, the highest designation under the USGBC standard for commercial interiors. The building also has earned a score of 90 (out of 100) from the Environmental Protection Agency’s “Energy Star” program. Skanska has earned a LEED–Commercial Interiors Platinum rating for its 2200 m2 offices on the 32nd floor.49 The project is designed to use the building as an open laboratory by having all the work and process available for study, replication and to be as a study methodology for other green retrofitting projects for skyscrapers. This open approach has attract the attention of officials including the U.S. Congress, the Obama administration, New York City’s Office of LongTerm Planning and Sustainability, cities around the world, and numerous real estate investors, managers and industry groups [USGBC 2014]. The Empire State Building is called “The World’s Most Famous Office Building” but now in the favor of the green retrofit “The World’s Most Famous Green Building”. This remarkable retrofit is pushing forward the New York’s plan to reduce current carbon emissions by 30% by 2030. In conclusion, the retrofit of the Empire State Building offers a stimulating prototype for other skyscrapers, particularly commercial ones that wish to enjoy a sustainable future [Ivanova, I 2013]. 48 48 Ivanova, I. Empire State Bldg’s Energy Savings Beat Forecast. Crain’s New York Business,24 June 2013. Available online: http://www.crainsnewyork.com/article/20130624/ REAL_ESTATE/ 130629951/empire-state-bldgs-energy-savings-beat-forecast

04.3.2 Willis Tower, Chicago, IL, USA

Fig:4.33 Chicago’s

Willis Tower opened in 1973. A modernization project aims to reduce energy use by 68 million kWh/yr.

The 110-story, 442 m tall Willis Tower, is a Chicago icon and the second tallest building in the Western Hemisphere after the World Trade Center in New York City. It’s Construction has been completed in 1973, as the empire state this skyscraper is also a major tourist attraction but in Chicago because of its observation deck attracts over one million people visitors yearly.50 Designed by the firm of Skidmore, Owings, and Merrill, and an innovative structural system developed by structural engineer Fazlur Kahn, having a striking exterior of black aluminum and bronze-toned glass. Partnering with Smith and Gill architectural firm and Environmental Systems Design a mechanical engineering firm Willis Tower has recently undergone a long-term green retrofit project. The retrofit plan projected Willis Tower’s base building 80% less energy equal to 64M kW·h annually and reduce its water use by 24 million gallons annually.51 The cost of the retrofit is estimated at $350 million.

(Sources:Sara Beardsley, AIA, LEED AP, 2010, High performance buildings, P.59)

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Fig:4.34 Base

building meter excluding tenant plug

loads (Sources:Sara Beardsley, AIA, LEED AP, 2010, High performance buildings, P.60)

Willis Tower greening and modernization plan include several features. The major energy savings feature is to replace the tower’s 16 thousand tinted single-pane windows with insulated glass 52. This retrofit measure is crucial to insulate the building from temperate weather in Chicago that fluctuates between extreme cold winter and hot summer. Instead of follow the tradition using insulated glass that involves doubling or tripling the glass panes for the Willis Tower, this option would be inappropriate tp add substantial load on the curtain wall. So, the plan suggested through adding insulating thin-film that will have the 49 Shaw, J. A Green Empire. Harvard Magazine, 2012. Available online: http://harvardmagazine.com/ 2012/03/a-green-empire 50 Lockwood, C. Building Retro. Urban Land, November/December 2009. Available online: https://www.esbnyc.com/documents/sustainability/uli_building_retro_fits.pdf 51 Meinhold, B. Sears Tower Going Green with $350 Million Renovation. Inhabitat, 2009.

Availableonline:http://inhabitat.com/sears-tower-going-green-with-350-million-renovation/

insulating properties of a triple-pane glazing while avoiding the triple glass heavy weight. It is estimated that this plan will provide effective day-lighting and save energy consumption required for cooling and heating the building. 51 Further than façade retrofit, the Willis Tower retrofit project suggests supplying new gas boilers to the building’s mechanical systems that utilize fuel cell technologies to generate electricity, heating and cooling with 90% efficiency. It will also upgrade the building’s 104 high-speed elevators and 15 escalators to reduce energy consumption. Further, like the empire state the project will install advanced lighting control systems to automatically adjust to optimal level of brightness and dim the lights when daylight is detected, to reduce energy consumption as well. It will also involve installing lowflow water fixtures on toilets, urinals and faucets to upgrade the building’s plumbing system and restrooms; as well as by providing irrigation systems and condensation recovery.

Integrating of green roof, wind turbines and PV panels to harness wind and solar energy was a part of the external retrofit to have less pressure on the electric grid.

Fig:4.35 Willis

Tower’s current façade is approximately 60% glass and 40% anodized aluminum panels (Sources:Sara Beardsley, AIA, LEED AP, 2010, High performance buildings, P.62)

Willis Tower is an important national and international landmark skyscraper similar to the Empire State Building that will likely inspire other skyscrapers to conduct green retrofits despite the involved initial costs. Chicago Loop contains hundreds of skyscrapers that are willing to retrofit. Further, it is estimated that the Willis Tower retrofit project will create 3600 jobs.52 128

Fig:4.36 The

project team plans to add renewable energy to the building. through technologies such as photovoltaic panels and wind turbines would be visible to visitors (Sources:Sara Beardsley, AIA, LEED AP, 2010, High performance buildings, P.60)

52 Boniface, R. Renamed Sears Tower to Get Green Retrofit. AIArchitect, 21 August 2009.

Available online: http://info.aia.org/aiarchitect/thisweek09/0821/0821d_sears.cfm

04.3.3 Taipei 101, Taipei, Taiwan As the world’s tallest building from 2004 to 2010 (Taiwan’s Taipei 101 skyscraper) has successfully earn LEED Platinum certification recently after going into a major green retrofit which is the highest level of achievement in the LEED system. Through three-year-long a green retrofit works the project achieved a significant savings on electricity and water and reducing and recycles waste. The results in reducing annual utility were the costs by $700,000 a year and the carbon dioxide emissions by nearly 3000 tons per year; and to understand this in different scale it is equivalent to removing 240 cars off the road.53 The upgrading of the tower electrical and mechanical systems of heating, ventilation, and air conditioning units involved in retrofit project including low-E glass and gray water system., as well as enhancing the tower efficient Siemens Apogee building management system, so that the owner management can monitor and analyze the energy consumptions more accurate. In addition, installing of temperature and humidity sensors on each floor so that they transmit information to the management system to decide turning on or off mechanical and lighting equipment.

Fig:4.37 The

tower successfully earned LEED Platinum certification—the highest level of achievement in the LEED system (Sources: Tobias, L. Why Taipei 101 Lifts Green Building, and Green Jobs, to New Heights, 2011. Available online: http://www.greenbiz.com/ blog/2011/10/31/why-taipei-101lifts-green-building-green-jobs- newheights)

Further, to avoid the overheating similar to the case of Bank of America Building, when electricity is cheaper, the building was equipped with “ice batteries” that make ice at night, , and then melts during the day to cool the building in hot summers. Finally the retrofit project includes other important features of the building including the irrigation system and food-waste recycling system. This is significant since the tower houses hundreds of restaurants.

53 Tobias, L. Why Taipei 101 Lifts Green Building, and Green Jobs, to New Heights, 2011.

Available online: http://www.greenbiz.com/blog/2011/10/31/why-taipei-101-lifts-greenbuilding-green-jobs- new-heights

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04.3.4 Adobe System Headquarter Complex, San Jose, CA, USA

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Headquarters of Adobe “software maker” engaged in a major retrofit project between 2000 and 2006, located in Downtown San Jose, CA, USA. The headquarter comprise three commercial high-rise office buildings: West Tower, East Tower, and Almaden Tower, completed in 1996, 1998, and 2003, respectively. In 2001, California experience rolling blackouts and spikes in energy prices, thus the government asked commercial users to reduce energy usage by 10 percent. In the other side, Adobe has worked on a green retrofit projects thanks to these projects the building earned Platinum LEED certification in 2006. The results of this project are reducing electricity use by 47%, gas use by 42%, and water use by 48%, and it costs about $1.4 million but its return on investment (ROI) of 121 % translated into $389,000 in Fig:4.38 In 2005, Adobe rebates and saving of $1.2 million a year. 54 expanded its green missionand began pursuing The project worked on stages, the first one was Adobe was the Leadership in Energy identifying utilities and equipment that were overusing energy. and Environmental Design For example, the parking garage’s exhaust fans were oper- (LEED®) certification for its ating unnecessarily 24/7. The preliminary study suggested San Jose headquarters that the fan running time could be reduced to be only 6 (Sources:Adobe Systems incorporathours, 3 hours during the morning rush-hour and 3 hours ed platinum certification for leadership during the evening rush-hour this will keep air quality above in energy and environmental design, required standards. Like Empire state building providing a P.01) Web-Based Intelligent Building Interface System (IBIS) was important improvement that monitors and control building’s equipment. The IBIS is run by a single software program and comprises 30,000 monitoring points that would ease the tasks of monitoring and control building’s subsystems by displaying electricity, water, gas, Uninterruptible Power Supply (UPS) systems, data centers and standby generators status in real time. In addition to the previous but it helps to work on adjusting lighting and temperature of the numerous zones of Fig:4.39 Garage exhaust fan the building individually, floor-by-floor, or the entire building re- Labor to reduce operating motely. Further, the IBIS helps in in significant annual savings times on garage supply through detecting and correcting problems ahead of time. 54 fans cost a total of just For water conservation strategy is also involved in the retrofit project. For example, improving of restroom facilities by installing automated flush valves, waterless urinals, faucets, and soap and paper-towel dispensers. Using local and drought-tolerant plants to reduce water and maintenance needs was a part of re-landscaping scheme, also upgrad54 Knox, R.H. Case Study: Adobe’s “Greenest Office in America” Sets the Bar for Corporate Environmentalism. FMLink. Available online: http://www.fmlink.com/article.cgi?type= Sustainability&pub=USGBC&id=40625&mode=source 55 Cammell, A. Adobe Systems’ Green Initiatives Generate Huge Savings. Tradeline, 29 July 2008. Available online: http://www.tradelineinc.com/reports/2008-7/adobe-systems-green-initiatives- generate-huge-savings

$100. This modification in the fans’ programming resulted in savings of approximately $67,000 per year with no compromise to air quality (Sources:Adobe Systems incorporated platinum certification for leadership in energy and environmental design, P.06)

ing the sub-surface drip irrigation system as it is more efficient than the spray irrigation system. Interestingly, Adobe using communication with local weather stations two satellite-based evapo-transpiration (eT) controllers to regulate irrigation through wireless technology,55 the system optimally adjusts the amount of the water flow according to local weather. For example, if the weather forecast predicts rain, the system will delay irrigation.

Upgrading chillers was a part of the improvements which it saves totaling approximately 300,000 kW·h ($39,000) annually by installing an adaptable frequency drive (AFd) 56. In addition Adobe works effectively on composting and recycling of paper, cardboard, plastic, glass, cans, printer toner, batteries, kitchen grease, it leads to diverting up to 95 percent of its solid waste from landfill. Adobe also depends on green cleaning methods that reduce health and environmental risks. Like refurbish with green materials are non-toxic, environmentally safe, VOC-compliant and biodegradable. Further, as a general ecological solutions Adobe has encouraged using green transportation means by installing locked bike cages and motivate its employees to use public transport. Resulting 20% of the employees commute by public transport, compared to 4% in the Silicon Valley. 55 Summary This chapter served as a review of major drivers, elements, and case studies related to an emerging and important project concerning green retrofitting skyscrapers. Indeed, the existing building stock of tall buildings is responsible for immense energy consumption and greenhouse gas emission and it is in a dire need to retrofit. Existing buildings represent the greatest opportunity to improve this performance. Early tall building curtain wall applications, not particularly efficient to begin with, are now approaching 40 years of age and more” 57. Economically, green retrofit is on demand as property owners and managers become convinced that a greener building now makes financial sense. That is because in recent years environmental retrofits have begun to pay off for owners and tenants alike.

Higher-profile companies are seeking out more efficient office space, and new technology at older buildings has started to translate into higher property values, leases and occupancy rates. “In a good market, we are going to get the best rents for the best tenants, and in a bad market like we have now, we’re going to get tenants when other buildings will not”58.

56 Tam, S.T. Skyscraper Green Retrofits Guide, 2011. Global Energy Network Institute (GENI). http://www.geni.org/globalenergy/research/skyscraper-green-retrofitsguide/Skyscraper-Green- Retrofits-Guide-FINAL.pdf 57 Council on Tall Buildings and Urban Habitat (CTBUH). CTBUH 2012 Shanghai Congress— Patterson, “New Skins for Skyscrapers”, 2013. Available online: https://www.youtube.com/ watch?v=WS5Aczhoifs.

58 A Landmark Sustainability Program for the Empire State Building. Available online: http:// www.institutebe.com/InstituteBE/media/Library/Resources/Existing%20Building%20Retro fits/ESB-White-Paper.pdf. Page:04

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Chapter 05 Building Performance Analysis

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Fig:5.00 BIM

uses a central model that can be extended for multiple purposes, including performance analysis Cost (Sources: Autodesk Building Performance Analysis and sustainability workshop, Building Performance Analysis (BPA), sustainabilityworkshop.autodesk.com)

/05 Building Performance Analysis methodology (BPA) The study in this chapter is to define a methodology for doing assessment for the building’s performance to see if the design goals achieved in different project phases, construction and building operation. Then it will describe the softwares will be used for building’s performance analysis, how the work and which Environmental standards used as a benchmark in these softwares so the architect can compare his new building/retrofitted performance one with these standards.

Overview on Building Performance Analysis (BPA) After understanding what is the building energy demands and know how to measure it and before starting to know how to do Building Performance Analysis, it might be helpful to know what BPA is, and why it’s important.

Building Information Modeling (BIM) is an approach to design that uses intelligent 3D computer models to create, modify, share, and coordinate information throughout the design process. Many AEC firms are using BIM to drive a more efficient design process.

In addition to driving a more efficient overall design process, BIM is powerful for sustainable design because it can help you iteratively test, analyze, and improve your design. This is called Building Performance Analysis (BPA). When used well, using BIM for building performance analysis can help you design sustainably. 1 The “i” in BIM drives analysis At the core of BIM is the information that’s stored in the model.

All of this data is stored and referenced in a back-end database that’s an integral part of the model.

This information includes the geometry of the project (shapes, layout), the physical properties of the materials (wall constructions, thermal properties, visual properties), the type of the spaces in the building, and schedules of operations of each part of the building. Other inputs that can be part of the model include the location of the building and weather files, which contain detailed information on such environmental characteristics as temperature, the sun’s path and wind patterns.

1 Introduction to building performance analysis| Autodesk Building Performance Analysis and sustainability workshop [webpage] https://knowledge.autodesk.com/search-result/ caas/simplecontent/content/building-performance-analysis-bpa.html [Accessed on 24 November 2017].

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Using this information, analysis engines can run simulations on things like HVAC sizing, energy use, water use, shading, and lighting levels. You can then make better design decisions by analyzing and documenting the expected performance of your design.

The infographic below explains how BIM and BPA are related, and what types of analyses can be considered building performance analysis. Whole Building Energy Analysis takes into account the interdependencies of the building as a whole system, so it is a particularly useful way to “keep score� as you work to reduce building energy use. Other performance studies like daylighting and solar radiation can help you improve aspects of the design. These studies are most effective when done in conjunction with energy analysis. 2

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Fig:5.01 BIM

and BPA relation, and what types of analyses can be considered building performance analysis (Sources: Autodesk Building Performance Analysis and sustainability workshop, Building Performance Analysis (BPA), sustainabilityworkshop.autodesk.com) 2 M. Flores, Building performance evaluation using Autodesk Revit for optimising the energy consumption of an educational building on subtropical highland climate, 2016.

Page:7

By using mathematical models of real-world phenomena, BPA and BIM can help designers predict the performance and cost of a building project during the design process.

The linkage of BIM to BPA tools can enable analysis to happen more quickly, more often and more smoothly during the design process. Without the direct link to a building information model, energy analysis can involve time consuming manual takeoffs of geometry from 2D plans.

One of the exciting promises of BIM is that it provides users with the ability to analyze building performance earlier in the design process, when design changes can be easier, less expensive, and more impactful.

05.1 Project Phases & Level of Development The building process has been refined over thousands of years. While every project’s process is slightly different, projects generally progress along these major phases. It’s important to know the right type and level of information that’s needed within each phase to add the most value.

05.1.1 Project Phases In the construction industry, the design process is described by the phases of pre-design, conceptual design, design development, and final design. The building life cycle process is described by the phases of construction and building operation. 3 05.1.2 Level of Detail (LOD) In order to efficiently manage the process of working in a BIM workflow, the industry has adopted a formal language of describing the completeness of a digital model at a given point in time. This language is “Level of Development” (LOD). LOD, in the BIM world, ranges from 100 (basic/conceptual) to 500

Fig:5.02 Typical Design Process of Buildings (Sources: Autodesk Building Performance Analysis and sustainability workshop, Building Performance Analysis (BPA), sustainabilityworkshop.autodesk.com)

3 Design process of buildings | Autodesk Building Performance Analysis and sustainability workshop [webpage] https://knowledge.autodesk.com/search-result/caas/simplecontent/ content/building-performance-analysis-bpa.html [Accessed on 24 November 2017].

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(highly detailed/precise). It is not unusual for levels of expected development to be part of the contract documents as described by the American Institute of Architect’s Building Information Modeling Protocol.

LOD phases can be summarized as follows • LOD 100: Modeled elements are at a conceptual point of development. Information can be conveyed with massing forms, written narratives, and 2D symbols.

• LOD 200: Modeled elements have approximate relationships to quantities, size, location, and orientation. Some information may still be conveyed with written narratives.

• LOD 300: Modeled elements are explained in terms of specific systems, quantities, size, shape, location, and orientation.

• LOD 400: Continuation of LOD 300 with enough information added to facilitate fabrication, assembly, and installation.

• LOD 500: Modeled elements are representative of as installed conditions and can be utilized for ongoing facilities management. 4

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It is worth mentioning that a relationship between LOD and design phases can be loosely established. However, it should be emphasized this relationship is not empirical. For instance a project as a whole may be in design development, but in the digital model, the building envelope system may be fully detailed with exact materials and thicknesses.

More so, plumbing systems might be represented with single lines, not modeled geometries.

Fig:5.03 LOD

and design process relation (Sources: Autodesk Building Performance Analysis and sustainability workshop, Building Performance Analysis (BPA), sustainabilityworkshop. autodesk.com) 4 LOD Spec 2017 Guide, 2011. For Building Information Models. Available at https:// bimforum.org/wp-content/uploads/2017/11/LOD-Spec-2017-Guide_2017-11-06-1.pdf

LOD and Building Performance Analysis Building Performance Analysis (BPA) is related to LOD on two fronts. First, what prevents modeled elements from progressing to the next step of LOD is the absence of information. The answers to discrete questions have not been found. BPA can be a mechanism for finding answers to these questions and informing the design process.

Secondly, digital methods of BPA are dependent upon the amount of information that is digitally modeled. Therefore it becomes beneficial to comprehend what LOD a model is at, and what that means in terms of available data, so analysis methods can be associated with the digital information that is readily available. For example, a model at LOD 100 will not allow one to conduct energy modeling that is required for LEED certification, but energy modeling with a LOD 100 can identify how the building’s energy consumption can be influenced by solar radiation. For these reasons, the LOD of a model and BPA practices share a feedback loop that at times are not as linear as the steps to developing levels of detail in the BIM model.

This may be best explained with the following graphic. 5

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Fig:5.04 Level

of Development and Building Performance Analysis Interaction Diagram (Sources: Autodesk Building Performance Analysis and sustainability workshop, Building Performance Analysis (BPA), sustainabilityworkshop.autodesk.com) 5 Ajla Aksamija, Tech Lab (Perkins+Will), 2012. BIM-Based Building Performance Analysis: Evaluation and Simulation of Design Decisions, Available at: https://pdfs.semanticscholar. org/973a/bbc6e6479bacafb2e0efc7cf86c1511e3840.pdf

05.2 Drawing the BPA connection After understanding BPA as a tool for answering design questions, while simultaneously relying on modeled information, relationships can then established to how certain BPA practices may be related to LOD and the time scale of how a design project evolves. The following are some examples of how these relationships work during the design process. 6 05.2.1 Pre-Design

Phase Objectives:

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Identify the requirements of the project, existing conditions, and unearth any essential information that will inform the design process. Common activities include preparing a building program, conducting a site analysis, and inventorying local code requirements.

Sustainable Design Inquires: •

What information will support BPA practices?

• What specific climate considerations should be brought to light?

• What is passive sustainable design strategies should be considered in the building design?

• What environmental resources can the building design utilize?

• What are the energy/performance goals for the project?

6 Project Phases & Level of Development| Autodesk Building Performance Analysis and sustainability workshop [webpage] https://knowledge.autodesk.com/support/insight/ learn-explore/caas/simplecontent/content/project-phases-level-development.html [Accessed on 24 November 2017].

LOD Assumptions: If a new project, there is no digital model available. If an existing building as in our research case, a digital project model might be available at a LOD 300.

BPA Actions: • Decide what climate data is most appropriate for the geographic location.

• Conduct a site analysis that minimally includes investigation of solar radiation , wind patterns , presence and condition of existing structures, inventorying existing vegetation, and documenting any acoustic challenges that exist.

• Analyze climate charts and determine if building is likely to be heating or cooling dominated.

• Research what sustainable design strategies would be applicable to both the geographic location, and climate zone of the project. Tools such as the 2030 Palette and Climate Consultant can help with this.

• Establish measurement matrices that are to be used throughout the duration of the project to confirm sustainable design goals are being accounted for. These can be formularized rating systems such as LEED and Breeam.

05.2.2 Conceptual Design

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Phase Objectives: Decide on the direction of the design by experimenting, iterating, and obtaining integrated design input from all parties.

The principle objective during this phase is to make high-level decisions that will provide direction to the entire design process.

Sustainable Design Inquires: • What is the most efficient building form?

• How is the building positioned on the building site?

• How is the floor plan organized?

• How do passive sustainable design strategies integrate with the building?

LOD Assumptions: Most of the architectural model is at LOD 100. The building form is digitally modeled in massing geometries, and the spatial relationships of the building program are sketched out with bubble diagrams.

BPA Actions:

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• Run conceptual energy analysis using and modifying massing forms and determine how the Energy Use Intensity (EUI) can be reduced by changes in building form, and orientation. Doing so can help determine the most energy efficient building form.

• Conduct basic shade/shadow analysis of the massing model to determine what areas of the building could potentially support daylighting, and consequently inform interior space planning. This also informs the positioning of the building on the site.

• Do solar radiation studies of the mass model to maximize opportunities for solar collection.

• Study how the orientation of the massing model interacts with wind on the site. Orientation of the building can optimize opportunities for passive cooling and ventilation.

05.2.3 Design Development

Phase Objectives: Verify and edit performative attributes of proposed design, while refining material, mechanical, and structural systems with specificity. This phase involves a lot of detailed experimentation and rigorous decision making.

Sustainable Design Inquires: • How should the floor plan be modified to improve the quality of day lighting?

• How can HVAC equipment be designed most efficiently?

• How can structural system be designed most efficiently?

• Do passive sustainable design strategies provide the expected performance?

• What materials are being used to construct the building?

LOD Assumptions: Architecture model is at LOD 200/LOD 300 with generic cladding materials identified, and floor plan is modeled with appropriate wall thicknesses and materials. Structural model is at least at LOD 200 with generic framing systems.

MEP model is at LOD 200 with plumbing, heating, ventilation, and cooling systems laid out, and ready to be sized.

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BPA Actions: • Run whole building energy analysis of building model, and identify how changes in wall construction can reduce energy demands. This also presents a good opportunity to test the performance of HVAC systems that were initially selected in Concept Design.

• Complete simulations that determine the general geometry of performative features to determine if shades, light shelves, and solar chimneys are working as predicted. If not, revise model geometry to do so.

• Run interior daylighting analysis of spaces, and confirm proper light levels are being achieved.

• After maximizing the efficiency of the building envelope, run cooling/heating load simulation so that HVAC equipment can be sized for efficiency.

• Perform structural analysis of model so that structural systems can be optimized. When structural members are not optimized for efficiency, the building consumes more construction materials than is needed.

05.2.4 Final Design and Documentation

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Phase Objectives: Provide detailed direction, and specification, to construct the most comprehensive iteration of the building. Assure that the constructed manifestation of the design will be as sustainable as feasibly possible.

Sustainable Design Inquires: • Are sustainable design goals achieved?

• Are building owner’s expectations of costs and performance achieved?

• What is the expected performance of the building?

LOD Assumptions: All models completed to LOD 300, with sizes and material selections finalized for all primary building elements.

BPA Actions: • Perform detailed whole building energy analysis of the final design to document expected performance, and measure against baselines. And compare final design against the measurement matrices that were defined in Pre-Design.

• Perform greenhouse gas emissions analysis to document expected environmental impact.

• Audit final building materials for costs and green qualities (recycled content, close proximity to construction site, low VOCs).

05.2.5 Construction

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Phase Objectives: Bring the building design into physical reality, by practicing sustainable construction methods and utilizing quality control methods.

Sustainable Design Inquires: • How can waste be reduced in the construction process?

• How can fabrication methods reduce waste?

• How can construction be done in a sustainable manner?

LOD Assumptions: Architecture, MEP, and Structural models are at LOD300 and are being evolved to LOD400 with enhanced information that supports fabrication and construction coordination.

BPA Actions: • Analyze building quantities to assure that exact material quantities are delivered to the project site. Doing so will avoid excess material that gets turned into waste.

• Analyze best fabrication methods with digital automation. This step reduces waste material in the production of building assemblies.

• Run construction scheduling simulations that identify how to reduce equipment operations on the project site.

Less use of construction equipment reduces both energy consumption and air pollution.

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05.2.6 Operations and Maintenance

Phase Objectives: The building becomes occupied and has all equipment operating.

Sustainable Design Inquires: • Are environmental control systems operating correctly?

• Is building able to maintain sustainable design goals when occupied?

• Is maintenance being done that assures environmental control systems can continue to perform at their optimum?

LOD Assumptions: All models are at LOD500, represent physical conditions, and are being updated in parallel with facility management operations.

BPA Actions: • Perform initial and ongoing commissioning of environmental systems to assure they are working as anticipated.

Poorly performing environmental systems can result in compromised occupant comfort, and unnecessary energy consumption.

• Add ongoing utility cost/demand data to energy model, and compare/identify differences between designed and actual performance.

• Administer occupancy survey to verify occupant satisfaction, and make recommendations to facilities management for improving occupant satisfaction.

05.3 BPA Software Workflows • Being deliberate about the analysis process using BIM can go a long way towards both saving time and improving the usefulness and validity of the results.

• Mapping out the project’s overall BPA workflow can help to understand how to use analysis as an integrated and iterative part of the design process.

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05.3.1 Knowing Goals and Metrics • The first step of the analysis process is creating a clear picture of what aspects of the design need to be optimized. This can help the designer to understand what tools to use, and what to look for in the analysis results.

05.3.2 Using Tools for Simulation & Analysis • Once the design goals and metrics are defined, the designer can start running simulations that compare various design alternatives and gain insights from the analysis results.

• It’s often best to first do some rough calculations to have an idea of what the designer would expect the results to look like before he runs the simulations. If his simulation results are way off, he will know that something’s wrong.

• Next, he will create a model that tries to approximate the physical reality as well as possible - or as well as is necessary for the precision of the simulation. This will often start with a high level conceptual model that illustrates the overall shape and form of the building with few details. As he iterate in his design process and progress in his analysis, he can add detail to his model to explore the aspects of the design that have the greatest impact on the building performance.

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• At each stage in the design process, he can simulate the building’s performance and generate insights that help guide his design strategy and next steps.7 05.3.3 Design Optimization Decisions • When using the Insight analysis tools, the designer receive information about the overall building performance based on the current assumptions in his energy model and feedback about specific factors that can help guide his design strategy to improve his building’s performance.

• Insight can help the designer to identify and focus his attention on the design factors that have the greatest impact on the overall building performance. It allows him to easily make changes to the assumptions used for these key design factors and immediately see the effect of these design decisions on the results. This enables him to see the impact of a wide range of viable assumptions for each major design factor as he optimizes his building’s performance.

7 V. Ismet Ugursal, 2014, Building Performance Analysis and Simulation: We’ve Come a Long Way Available at: www.mdpi.com/2075-5309/4/4/762/pdf

Fig:5.05 Energy Analysis of the Audubon Center using Insight (Sources: Autodesk Building Performance Analysis and sustainability workshop, Solar Measurements & Strategies, sustainabilityworkshop.autodesk.com)

• For each design factor, the performance impacts of the assumptions in his model are presented relative to a range of potential values for that factor. For example, for all the Windowto-Wall Ratio (WWR) factor a range of potential values from 0% to 90% WWR is offered. The Insight interface for each design factor allows him to easily change the range of values to be considered in the analysis and see the impact on the mean energy performance as he makes the changes. As he continue his design process and focus his design decisions, he can narrow these ranges to drive toward more precise results.

• To help the designer to get the maximum benefit from the results and improve his design, Insight provides a benchmark comparison that allows him to see how his design performs in comparison to industry benchmarks such as ASHRAE 90.1 and Architecture 2030.

• With Insight, the designer can also easily evaluate many design alternatives (different shapes, sizes, locations) and use scenarios to quickly apply consistent assumptions to several models for accurately comparing the results.

• By following this process, he will be prepared to make an informed design decision. 8 8 Daniel Overbey AIA, 2016, Building Performance Modeling Tools for Any Designer [webpage] http://danieloverbey.blogspot.com/2016/04/building-performance-modeling-tools-for.html

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ANSI/ASHRAE/IES Standard 90.1-2016: Energy Standard for Buildings Except Low-Rise Residential Buildings.

It has been a benchmark for commercial building energy codes in the United States and a key basis for codes and standards around the world for more than 35 years. 9 The 2030 Palette: is a free online platform that sets out the principles and actions for designing low-carbon/carbon neutral resilient structures, communities and cities worldwide. 10 05.4 Autodesk Insight Tools Autodesk provides tools that can help to analyze the building’s performance at all stages of the design process. These tools can help to understand the factors that impact the building’s performance in order to make informed decisions about the new design.

In the next chapters we will go deeper to know in details the procedures and the workflow of Revit and Insight to analyze the proposed case study before and after retrofitting to know which is the best design solutions in matter of cost and energy use. 11

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Fig:5.06 Insight

building performance analysis features (Sources: Screenshot from insight plug-in for Autodesk Revit, available at https://insight360. autodesk.com)

05.4.1 Insight Energy Optimization Insight is an analysis tool that provides information about the building’s projected energy use and the energy costs associated with meeting that demand. Insight includes two tools focused on Energy Optimization: • Insight’s Generate tool creates an energy analytical model for the design and submits that model to the Insight cloud service, where a wide variety of design options and alternatives are generated and evaluated to report a range of potential performance outcomes.

9 S Goel, 2017,ANSI/ASHRAE/IES Standard 90.1-2016 Performance Rating Method Reference Manual Available at: https://www.pnnl.gov/main/publications/external/technical_reports/PNNL-26917.pdf 10 E. Mazria, 2010,How we plan and design the built environment from here on out will determine whether climate change is manageable or catastrophic. Available at: http://2030palette.org/

• Insight’s Optimize tool provides access to the results of the analysis in the Insight web interface, which allows exploring, and changing key design factors and seeing the impact of these choices on the overall building performance.

05.4.2 Insight Solar The Insight Solar tool can perform many types of solar analyses on the building’s model. The results of these selected analyses are displayed in the Solar Analysis window, as well as being displayed visually as color gradients on the model surfaces.

While Insight Solar is not intended to be used for sizing PV panels, it can help to identify locations for maximum solar gain by considering the effect of shading and seasonal variation in solar radiation.

05.4.3 Insight Lighting The Insight Lighting tool allows performing lighting analysis studies for the building. The designer can perform different types of studies including LEED Daylighting and Illuminance.

05.4.4 Insight Heating and Cooling This Insight Heating and Cooling tool performs an analysis of the new design using EnergyPlus to determine the heating and cooling loads. The heating and cooling loads in the baseline model are calculated using EnergyPlus hourly simulation engine for design days.

11 K. FUHRMAN, 2016, AUTODESK UNIVERSITY, Insight 360: Energy Analysis . . . for Architects? Available at: http://au.autodesk.com/au-online/classes-on-demand/class-catalog/2016/revit/ar16137#chapter=0

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Chapter 06 Torre GALFA Green retrofitting

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Fig:6.00 3d

Render showing how the envelope of Torre GALFA will be after applying the environmental solutions (Redraw by author according to the original drawing)

/06 Energy assessment and green retrofitting methodology for Torre GALFA This study on torre GALFA will contain a method showing how applying diffrent green elements (studied in the former chapters) will help the building to go towards being a net zero building. This method will start by energy assesment of the new refurbishment done to torre GALFA by BG & K studio to use it as a datum first, then it will compare different assesment scenarios for the tower after adding the mentioned green solutions on the first datum to see which green element is more useful for this case study.

Overview on Torre GALFA The GALFA Tower is a skyscraper in Milan, Italy, located in the Centro Direzionale di Milano district, beside the centeral station. It was designed by architect Melchiorre Bega in 1956 and completed in 1959. Regarding to the location of the tower, its facades looking on Via Galvani and Via Fara. The names of these two streets was a driver to the name “GALFA”. The building is 102 m and 31 floors high, with 2 more underground floors, and qualifies as the eleventh highest skyscraper in Milan.

The overall design of the tower is mainly based on the International Style architecture. The building is rectangular, with the two lowest floors larger than the main body. The main structure in reinforced concrete is almost completely hidden by curtain walls made of glass and aluminium.

The tower was originally built for the Sarom company; in the mid-1970s, it was sold by Sarom to the Popolare di Milano bank, and thereafter served as a service centre and headquarter of the bank. In 2006, Popolare sold the building for 48 million euros to Fondiaria Sai Group.

On 5 May 2012, the building was occupied by a group of people which intended to create a space for artists; the project’s name was Macao.The building was cleared by the authorities ten days later; anyway, project Macao remained, and Milan’s Major Giuliano Pisapia promised to provide it another seat.

The Unipol Group, that acquired Fondiaria-Sai in 2012, has just taken possession of the building, has started together with The Council of Milan the study on the project of requalification and valorisation of the tower and its vicinity with the objective of starting the work within 2014. 1 1 2012,Torre Galfa, Past and Future - From the archive - Domus Available at: https://www. pnnl.gov/main/publications/external/technical_reports/PNNL-26917.pdf

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Construction techniques of the original design Building Strcuture and Facade system Torre GALFA has a particular structure with load bearing structure which are reduced in section while increasing in height. In its perimeter are clear of any hard element and allows the realization of a continuous curtain in completely transparent glass, with the exception of some portions of the back occupied by the service core.

The volume is closed at the top by an aerial concrete shelter that covers the panoramic terrace.In other way you can say it is a rational block of cement and glass, 31 stories, 103 meters high. A pure volume, in lines, and totally transparent.

The load-bearing structure of the building consists of six large “wings� of reinforced concrete, differently oriented, set back from the external wire that is covered by curtain-wall : continuous glass windows and duralumin, far from the structure, which give the characteristic lightness and which allow us to glimpse the modern open-space interiors.

The perimeter closures are made with a continuous glazing created by the Greppi brothers with the maximum dimensions reached then for glass sheets.

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The internal architecture is completely coherent with the external one: the spaces follow each other around the fifth pillars, avoiding the annoying distribution in watertight cells and confirming with the internal spatial unity, that volumetric ache characterizes the exterior with such clarity. The coherent concept that saw the open space as a rule of office building design is evident. In those years, based on the American model, the typological studies on office space, based on the concept of modularity and maximum flexibility, were born. 2

2 Laura Greco, Stefania Mornati, 2012,La Torre Galfa di Melchiorre Bega Architettura e Costruzione

Fig:6.01 Floor

plan of Torre GALFA showing the 6 wings of the load bearing structure

0.538 0.484

(Redraw by author according to the original drawing)

Guida per scuri

1.45

Rivestimento in metallo Bilico orizzontale Bilico verticale

1.05

Pannello in plastica Vasistas

0.484

Putrella montante esterno

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Fig:6.02

0.75

1.5

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Plan/Section/Elevation of the glass facade of Torre GALFA original design

(Redraw by author according to the original drawing)

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06.1 Pre-design phase Phase description Interior comfort necessities through studying the existing structure, climate and natural resources available on the building site.

Phase objective Identify the requriments of the project, existing conditions, unearth any essential information that will inform the design process. For example (building program, conducting site analysis and understanding the local climate).

06.1.1 Condition of the existing structure (GALFA Refurbishment) Now that the GALFA tower is finally being renovated from it’s horstical cloak - the reopening is scheduled for 2019,the market gives it the impossibility of keeping the destination in an office, as the inter-floor designed inter-floor that is too small compared to today’s needs, the new design contains a mixture of residential, hotel and commercial functions (Fig.6.02).

“From an urban point of view, the operation has two new objectives, to allocate space to the ground floor for public use and to restore the building’s recognizability in the new city skyline. From the architectural point of view the challenges to be faced have been different”. (Kannah 2017) 3

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Redesign of the ground floor was more entertainment change.On the front of Via Galvani, a the shopping area, the hotel and the restaurant introduced by a crystal cube with a water basin. The entrances to the residences are not concentrated on Via Campanini, but it also marked by a square “pool” with round boxwood bushes and marble seats.

A crystal volume has been added on the side of the tower which houses new ramps and lifts, as well as modular stainless steel elements that enclose the systems (air treatment and heat exchangers) “To ensure efficiency, comfort and the safety of the skyscraper compared to the regulations, we had to create new staircases and lifts. The heights of the interpiani instead are the original ones. And so the score of the frames, which preserves intact the geometry of the structure, updated in the materials with new profiles of natural anodized aluminum and transparent glass “.(Kannah 2017) (Fig:6.04). 3 3 Cecilia Bolognesi, 2017,Il ritorno di un classico Available at: https://www.pnnl.gov/ main/publications/external/technical_reports/PNNL-26917.pdf

Fig:6.03 New

functions by floor according to the new design (Redraw by author according to the original drawing)

At the top of the building, in place of the old technical volume of the facilities, a restaurant with a panoramic terrace is under construction. Easy prediction: it will become one of the cult destinations of the city.

- Refurbished design elements ¦ ¦ Double-skin façades with cavity of 25 cm Horizontal Continuity: 3.6 meters and Vertical Continuity: 2.9 meters (floor-to-floor) ¦ ¦ Triple Glazed panes in the curtain walls instead of two panes. ¦ ¦ Renew the main energy generator of the tower. ¦ ¦ Adding Geothermal energy and photovoltaic panels in the roof ¦ ¦ Adding high efficiency heat pumps ¦ ¦ Controller based on WEB server technology to manage the automated air conditioning system ¦ ¦ Adding photovoltage panels on the rooftop ¦ ¦ Percentage of Annual Energy Savings for Heating and Cooling:-- % compared to a fully airconditioned Italian office building (simulated) ¦ ¦ Typical Annual Energy Consumption (Heating/ Cooling):-- 249 kWh/m2 (simulated) ¦ ¦

Type of PV modules Monocrystalline solar panels

¦ ¦ Thermal transmittance of concrete shear walls 200 mm: 0.359 W/m2K ¦ ¦ Thermal transmittance of triple insulated glazing 44 mm with argon filling: 0.6 W/m2K ¦ ¦ Thermal transmittance of Insulated concrete roof 300mm: 0.6 W/m2K ¦ ¦

Refurbishment cost: aprox. 100 million euros

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  TOILET

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SHOWER

HOTEL BEDROOM

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Fig:6.05 Typical floor plan configuaration changed from office building to be a hotel (Model by author according to the original drawing)

Refurbishment elements in Torre GALFA

150 MM BRICKS INTERNAL WALL

0

37

25

90

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INSIDE: SINGLE LAYER LAMINATED GLASS WALL 160 SYSTEM

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OUTSIDE: LAMINATED AND COATED 3 PANE INSULATED EXTERIOR GLAZING

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250 MM AIR GAB BETWEEN DOUBLE FACADE SYSTEM

26X14MM VERTICAL MULLION ANCHORED WITH INTERNAL REINFORCMENT IN THE INTERNAL WALL 2710

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ROOM ENTRANCE

20X10MM VERTICAL MULLION ANCHORED IN WITH THE SLAB 500x300cm grid for external air intake local technical ventilation towards open space

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0 15

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400 MM CONCRETE RIBBED FLOOR SLAB

Fig:6.06 Triple Glazed panes in the curtain walls instead of two panes with a mechanical ventilation system works through the linear C/S louvers (Model by author according to the original drawing)

5

170 400

Fig:6.07 113 Sqm new core attached to the old one (source: Planimeter 2017)

Fig:6.04 Renovated

elements by BG & K associate that directly affecting the energy consuming.

170 400

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62

2710

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38

2710

62

170 400

(Model by author according to the original drawing)

Fig:6.08 Outward-facing bedrooms are ventilated directly through HVAC closed loop water system using a double-skin faรงade system to fasten the air speed (Model by author according to the original drawing)

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Natural Ventilation Strategy

1450

538

484

1005

The outward-facing bedrooms are ventilated directly through a double-skin faรงade system, with inwad HVAC closed loop water system. The inward-facing bedrooms are ventilated via rising stack buoyancy in the double facade,assisted by wind flowing from the HVAC system.

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484

1005

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Fig:6.09 Plan, 3d section & facade of the glass double facade used for the natuaral-ventiliation strategy showing how the closed loop water system works to change the internal tempreature through a hybrid system between a mechanical HVAC and stack effect in the double facade (Model by author according to the original drawing)

3500 3280 3280 3280 3280 3280 3280 3280 3280 3280 3280 3280 3280 3280 3280 3280 3280 3280 3280 3280 3280 3280 3280 3280 3280 3280 3280 3280 3280 3280 4280

Fig:6.10 Section Every floor has a meter curtain wall in the south east facade. With this arrangement there is always a windward in each room which is ventilated through air moving from the closed loop water system.

(Drawings by author according to the original drawing) 163

Fig:6.11 Plan The outward-facing bedrooms are ventilated directly through a double-skin faรงade system, with inwad HVAC closed loop water system. The inward-facing bedrooms are ventilated via rising stack buoyancy in the double facade,assisted by wind flowing from the HVAC system (Drawings by author according to the original drawing)

06.1.2 Site analysis and local climate

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Analysing the local climate is a must as it will give you the direction to use the climate elements like wind direction and intensity to use it mostly in the favor of passive green design and not against it.

In Milan, capital of the Italian region of Lombardy, the climate is moderately continental, with cold and damp winters, and hot and muggy summers.

Rainfall is well distributed over the seasons, though there is a relative minimum in winter, and two relative maxima in spring and autumn. From May to August, thunderstorms can break out in the afternoon or evening.

Winter, from December to February, is cold, wet and gray.

Temperatures often remain around freezing (0 °C or 32 °F) also in the daytime, and the sky remains overcast for long periods. Fog, once very common, has become quite rare within the city, where the so-called urban heat island effect also makes the temperature less cold, especially at night.

The wind is usually weak or absent, except when the Föhn blows, a warm and dry wind that comes down from the Alps, and is able to bring clear skies and good visibility (a sign of its presence, in addition to mild air, is the possibility to see the snow-capped Alps).

As you can see on the windrose of milan the privilege wind direction is almost from WSW, SW, ESE and E, but this is not all the year long for example the E and ESE wind is blowing through summer and shoulder season but for WSW, SW is almost all the year and this will affect directly the diffrent the passive design strategy that will use the wind direction like cross-ventlation or cooling the external envelope.

There’s no shortage of rainy days, even though the winter is relatively dry compared with the other seasons. Snow usually falls at least once every year, and sometimes can be abundant, but tends to melt soon enough. In the city, because of the heat island, snow accumulates with more difficulty than in the surrounding countryside and in the hinterland towns.

Every now and then, cold air masses from Eastern Europe can bring fairly intense frosts, though the temperature rarely drops below -10 °C (14 °F).

Typically, from the second half of February, the temperature tends to increase, and highs exceed quite often 10 °C (50 °F). 4 4 2017,CLIMATE: MILAN Available at: https://en.climate-data.org/location/1094/

Spring in Milan is initially unstable, and gradually becomes a pleasant season, especially from mid-April to late May, when there are many sunny days, with mild or pleasantly warm temperatures during the day. In March, the first mild days alternate with cold days; in April it can still be quite cold, especially in the first half of the month. Atlantic depressions, which cause rainfall, are quite frequent. In May, the first afternoon thunderstorms may occur.

Summer, from June to August, is hot and muggy, and generally sunny. The heat is felt due to high humidity and low or no wind, which are conditions typical of the Po Valley, but also to the fact that in the city the heat is trapped between buildings. Sometimes an Atlantic front, able to bring cool and rainy weather, can pass also in summer; more often, on sunny days, thunderstorms can erupt in the afternoon and in the evening.

Autumn offers several nice days in September, and sometimes on early October, then quickly becomes cloudy and rainy. The first cold days typically occur in November. Overall, autumn is the rainiest season of the year. Although the number of rainy days is not too high, when it rains, the rain tends to last several

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TEMPRETAURE

MONTHS

Fig:6.12 Wind Rose (source:Climater to travel)

Fig:6.13 Average Annual Temperature (source:Climater to travel)

Profile (°C)

hours, even the whole day.

The amount of sunshine in Milan is low from mid-October to February, when sunshine is rare, and even when the sun comes out, it is often weak and veiled in mist. On the contrary, there’s no shortage of sunshine in spring, while it is quite frequent in summer, except for the albeit rare rainy days and the more frequent afternoon thunderstorms. 6 Climate data ¦ ¦ Location

Milano, Italy ¦ ¦ Geographic Position

Latitude 45° 29’ N, Longitude 9° 11’ E ¦ ¦ Climate Classification

Temperate oceanic climate ¦ ¦ Prevailing Wind Direction Southwest ¦ ¦ Average Wind Speed

4 meters per second ¦ ¦ Mean Annual Temperature

8 °C ¦ ¦ Average Daytime Temperature during the Hottest Months (June, July, August)

25 °C ¦ ¦ Average Daytime Temperature during the Coldest Months (December, January, February)

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Fig:6.14 Sunshine hours (source:Climater to travel)

Fig:6.15 Average Relative Humidity (%) and Average Annual Rainfall (source:Climater to travel)

¦ ¦ Day/Night Temperature Difference During the Hottest Months

11 °C ¦ ¦ Mean Annual Precipitation

1013 millimeters ¦ ¦ Average Relative Humidity

75% (hottest months); 76% (coldest months) 06.1.3 Sustainable strategies applicable to the geographical location and climate zone of the project Identifying the sustainable strategies by converting dozen of raw climate data into a psychometric chart contains the temperature and humidity of each of the 8760 hours per year.

The percentage of hours that fall into each of the 16 different Design Strategy Zones gives a relative idea of the most effective passive heating or passive cooling strategies.

06.1.4 Establsihing measurment matrices

Torre GALFA energy analysis (EUI Baseline) Energy intensiveness is simply energy demand per unit area of the tower’s floorplan. This allows us to compare the energy demand of building before and after doing other design solutions, so we can see which green retrofitting design element performs better in a matter of building energy.

The following schemes is simulated through two softwares Revit for BIM modeling and Insight for energy analysis, and together worked in diffrent phases to go through a simulation very near to the real project so we can understand the affect of every design descision on the energy use point of view and also give the possibilty to compare between this solutions with our datum (the refurbished building) and also to compare it with ASHRAE 90.1 standards. (Fig:6.17) The following schemes extracted from a complex model done at level of details (L.O.D) 300 on revit then other design variables has been specified like the type of glass, double facade detail and building orientation.

Energy settings are explained in the graphic at right, and the energy use intensity (EUI) of the baseline (refurbished tower) was found to be 353 kWh/m2/year. (Fig:6.16) Torre GALFA design variables In greenretrofitting there are limitless variables that can directly affect the building energy performance but here we will try

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Fig:6.16 Energy Use Intensity (Model by author according to the original drawing)

Energy Use cost (Model by author according to the original drawing)

Fig:6.17 Energy Use Intensity compared with ASHRAE 90.1 benchmark (Model by author according to the original drawing)

Energy Use cost compared with ASHRAE 90.1 benchmark (Model by author according to the original drawing)

Fig:6.18 Energy simulation for torre GALFA (Model by author according to the original drawing)

Energy amount use KWH/m2a

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Fig:6.19 EU Specific energy use (KWH/m2a) in the hotel buildings Source (D’Agostino, Zangheri and Castellazzi 2017)

to study some variables which have the highest impact (for example: window to wall ratios) The following shown variables are fixed in the new design done by bg&k associati. basically in this area we can explore the impact of changing these variables through diffrent passive,active and hybrid systems on the EUI of the building and compare it with our datum (Fig:6.17) which is refurbished torre GALFA. Insight as a software allows us to adjust the range of values being considered for the thermal properties of different constructions in the building. This provides helpful information to assist the designer decision making. ¦ ¦ Building’s operating schdule 12/7 ¦ ¦ Window to wall ration (Eastern walls) 92% ¦ ¦ Window to wall ration (Westren walls) 43% ¦ ¦ Window to wall ration (Southren walls) 22% ¦ ¦ Window to wall ration (Northen walls) 59% ¦ ¦ Window Glass (East) Triple glazed pane low E ¦ ¦ Window Glass (West) Triple glazed pane low E ¦ ¦ Window Glass (South) Triple glazed pane low E ¦ ¦ Window Glass (North) Triple glazed pane low E ¦ ¦ Wall construction Insulated 200 mm concrete shear wall ¦ ¦ Lighting efficiency N/A ¦ ¦ Windows shade - East (No shade) ¦ ¦ Windows shade - West (No shade) ¦ ¦ Plug loads Efficiency 23.6 w/m² ¦ ¦ Roof construction Insulated 300 mm concrete roof slab ¦ ¦ PV Panel efficiency N/A ¦ ¦ PV Payback limit N/A ¦ ¦ PV Surface coverage N/A

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06.1.5 Torre GALFA Solar analysis Incident Solar Radiation/PV energy analysis Data for direct and diffuse solar radiation are included in the weather files that analysis software uses. So the incident solar radiation values shown actually calculated and visualized based on basic building geometry. The goal from this analysis is to maximize the oppurtiunities for solar collection. The software takes the hourly direct and diffuse radiation data from weather data, the building geometry, and the time period of the analysis into account. It also includes shading from surrounding objects (Fshading), the portion of the sky “visible� by the surface (Fsky), and the angle of incidence between the sun and the face being analyzed (theta). Since incident solar radiation is just a measure of the amount of sun hitting a surface, it does not depend on material properties.

Solar analysis usually equates to heat if it is allowed into a building or electricity if it is captured by a PV array.

The Potintial that torre galfa can produce PV energy is 1,452,917 KWH/Year ($348,700 energy saving) and the building energy offset is 15,314 m² PV panel area (16.3 years back)

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Fig:6.20 Solar shades analysis for (Model by author according to the original drawing)

Conduct shade/shadow analysis The purpose of these analysis is to understand what areas of the building could potentially support daylighting could potentially support daylighting and how it could affect the illumiance rates in interiors.

March 9 am

March 12 pm

March 3 pm

June 9 am

June 12 pm

June 3 pm

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September 9 am

September 12 pm

September 3 pm

December 9 am

December 12 pm

December 3 pm

Fig:6.21 Shadow and shade for Torre galfa (Model by author according to the original drawing)

06.1.6 Torre GALFA daylighting analysis Basically this analysis calculats the amount of light falling on a surface in the interior spaces to find the areas have isuffiecient proper light level. the amount of light called “illuminance”, and is measured in lux or lumen/m2. This is the measurement we will work with the most for optimizing visual comfort because building regulations and standards use illuminance to specify the minimum light levels for specific tasks and environments.

This value does not depend on the material properties of the surface being illuminated. However, since the amount of light the surface “sees” depends on how much is being reflected from other surfaces around it, it does depend on the color and reflectance of the surfaces that surround it.

As the main function of Torre galfa is an hotel so the minimal demand for visuall acuity regulations regarding the bedrooms should not be less than 200 lux. but as shown in the illuminance render it meets the requirments in a small area around the window but not well distributed around the whole space.

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September 21 12 pm

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December 21 12 pm

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Fig:6.22 Daylighting studies for Torre galfa in diffrent peak points for the sun direction and intensity (Analysis by author according to the original drawing)

06.1.7 Wind Pressure effects on Torre GALFA external facade CFD modelling was used to predict airflow patterns around the air flow pattern around Torre GALFA and it shows how strong postitve pressure pushing on the east facade most of the year. This can be used as one of the variables in the natural ventilation strategy, there is less certainty of delivery than with a traditional mechanical ventilation system. It is even more important to adequately model and predict the ventilation performance prior to final design and construction.

There are several techniques that can be used to aid the design of naturally ventilated buildings, with wind tunnel testing, computational fluid dynamics (CFD), and salt bath modeling being the most common.

The result of these simulations should then be used to inform the configuration and sizing of façade apertures such as window openings and the optimized shape of the building form to use the pressure diffrence in the natural ventlation startegies.

06.1.8 Torre GALFA Heating/cooling loads

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Thermal loads are the quantity of heating and cooling energy that must be added or removed from the building to keep people comfortable. Thermal loads come from heat transfer from within the building during its operation (internal, or core loads) and between the building and the external environment (external, envelope, or fabric loads). These thermal loads can be translated to heating loads (when the building is too cold) and cooling loads (when the building is too hot).

These heating and cooling loads aren’t just about temperature (sensible heat), they also include moisture control (latent heat). The purpose is to find diffrent passive design elements to arrive or near to net zero energy building and to resize the HVAC for efficency so the building can arrive to the ultimate internal thermal comfort.

Heating and cooling loads calculated according to each room in a single floor. As illustrated on the floor plan it splitted to 5 different zones contains 12 bedrooms, 2 services rooms and the hotel corridor.

In the attached table the heating and cooling demands has been calculated to each element in the spaces and also generally to the rooms.

Fig:6.24 Hotel 3d view showing 1 floor splitted to zones and spaces to be a legend in the heating and cooling demands calculations (Analysis by author according to the original drawing)

Fig:6.23 CFD modelling used to predict air flow pattern around Torre GALFA to understand the pressure diffrence on the buiding envelope (Analysis by author according to the original drawing)

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Fig:6.25 Hotel floor plan splitted to zones and spaces to be a legend in the heating and cooling demands calculations (Analysis by author according to the original drawing)

Project Summary Location and Weather Project

Torre GALFA

Address

Via Luigi Galvani, 20124 Milano MI, Italy

Report Type

Wednesday, June 27, 2018 11:30 AM Standard

Latitude

45.49°

Longitude

9.20°

Summer Dry Bulb

29 °C

Summer Wet Bulb

22 °C

Winter Dry Bulb

-5 °C

Mean Daily Range

10 °C

Calculation Time

Building Summary Inputs Building Type

Retail

Area (m²)

277

Volume (m³)

798.48

Calculated Results

Peak Cooling Sensible Load (W)

80,310 September 12:00 PM 74,838

Peak Cooling Latent Load (W)

5,472

Maximum Cooling Capacity (W)

91,772

Peak Cooling Airflow (L/s)

6,235.10

Peak Heating Load (W)

22,729

Peak Heating Airflow (L/s)

1,253.90

Peak Cooling Total Load (W) Peak Cooling Month and Hour

Checksums

176

Cooling Load Density (W/m²)

289.67

Cooling Flow Density (L/(s·m²))

22.49

Cooling Flow / Load (L/(s·kW))

77.64

Cooling Area / Load (m²/kW)

3.45

Heating Load Density (W/m²)

81.98

Heating Flow Density (L/(s·m²))

4.52

2 Spaces Volume (m³)

Peak Cooling Cooling Airflow (L/s) Load (W) 10,930 812.1

Peak Heating Heating Airflow (L/s) Load (W) 2,168 153.7

Space Name

Area (m²)

1 Bedroom 2 Bedroom 3 Bedroom 4 Bedroom 5 Bedroom 6 Bedroom 7 Bedroom 8 Bedroom 9 Bedroom 10 Bedroom 11 Bedroom 12 Bedroom 13 Service 14 Hotel corridor 15 Service

21

60.64

18

52.24

7,066

526.3

617

66.4

19

55.2

7,591

565.4

653

70.3

19

53.65

7,572

564

672

70.3

19

53.52

7,570

564.2

674

70.3

19

55.48

7,613

567.4

654

70.4

17

49.22

7,519

560.4

726

70.2

12

35.91

8,428

594.3

1,647

110.2

12

35.93

5,275

401.5

1,653

110.2

12

34.59

1,953

146.8

1,108

80.4

12

35.04

1,953

131.8

1,128

79.9

19

53.45

6,002

448.5

2,183

146.7

4

10.16

373

26.6

432

28.7

69

198.03

2,795

179.2

-1,313

66.3

5

15.43

2,231

146.7

965

59.9

Space Summary - 1 Bedroom Inputs Area (m²)

21

Volume (m³)

60.64

Wall Area (m²)

34

Roof Area (m²)

0

Door Area (m²)

5

Partition Area (m²)

0

Window Area (m²)

28

Skylight Area (m²)

0

Lighting Load (W)

340

Power Load (W)

431

Number of People

3

Sensible Heat Gain / Person (W)

73

Latent Heat Gain / Person (W)

59

Infiltration Airflow (L/s)

0

Space Type

Retail (inherited from building type)

Calculated Results Peak Cooling Load (W)

10,930

Peak Cooling Month and Hour

October 10:00 AM

Peak Cooling Sensible Load (W)

10,868

Peak Cooling Latent Load (W)

62

Peak Cooling Airflow (L/s)

812.1

Peak Heating Load (W)

2,168

Peak Heating Airflow (L/s)

153.7

Components Wall Window

Cooling

Heating

Percentage Loads (W) of Total 16 0.15%

Percentage of Total 183 5.00%

Loads (W)

10,238

93.67%

2,729

74.65%

Door

0

0.00%

0

0.00%

Roof

0

0.00%

0

0.00%

Skylight

0

0.00%

0

0.00%

Partition

0

0.00%

0

0.00%

Infiltration

0

0.00%

0

0.00%

242

2.22%

-251

-6.86%

Lighting Power

307

2.81%

-318

-8.69%

People

127

1.16%

-176

-4.80%

0

0.00%

10,930

100%

2,168

100%

Plenum Total

Fig:6.26 Heating and cooling loads in each space/zone/element (Analysis by author according to the original drawing)

177

06.2 Design development phase Phase description Define various green design elements that can be used in the retrofitting phase and integrate them through passive strategies/high efficency active systems to achieve the thremal, visual, acoustical comfort,and air quality conditions using the minimal usage of energy.

Phase objective Choosing the design elements/strategies through expreminting, iteration and obtaining integrated design input from all project parties.

Verify and edit performative attributes of proposed design, while refining materials, mechanical, and structural systems with specificity.

06.2.1 Refurbished GALFA Datum After the Energy usage internsity simulation the software insight give some guidlies to help to choose the right strategy that will help the building to consume less energy.

WWR 59% North

WWR 43% West

178

WWR 92% East WWR 22% South

North direction prevailing wind direction WWR Window to wall ratio Sun path directions Fig:6.27 Climatic/design and energy use data for Torre galfa (Model by author according to the original drawing)

Insight simulation recommendations _ Change Eastren walls -WWR from 92% to 40% will save around 40 KW/sqm. _ Adding window shades (east facade) at 1/3 of window highets will save around 24 KW/Sqm. _Adding high eff. HVAC and heat pumb. _Increase the lighting efficency _Upgrade the roof insulation materials _Upgrade PV panel efficency _ Add more PV surface coverage 06.2.2 Service core position In torre galfa there are two services cores, one in the westren facade in the premiter of the building which was included in the old design of Melchiorre Bega and another one which is attached externaly to the same facade and to the old core.

As it described before in former chapters the service core is not only structural ramifications, it also affects the thermal performance of the building and its views.

But the position of the new one it will not affect much the thermal performance as much as it can be designed to fit on the eastren facade.

In this case study we will start to redesign the service core on the eastren facade to see how much it will affect the plan configurations, views and the more important for the focus of this study is the thermal performance of torre galfa.

179

180

Fig:6.28 Changing the position of service core from the westren to Eastren facade and the effect on the energy consumption (Model/simulation by author according to the original drawing)

ROOM 01

ROOM 02

ROOM 03

ROOM 04

Fig:6.29 Changing of the core position will ban the connection with the old core and it close the external view for 4 main Hotel rooms (Model/simulation by author according to the original drawing)

06.2.3 Facade orientation A Energy usage internsity simulation the software give some guidlies to help to choose the right strategy that will help the building to consume less energy.

These strategies works with sun orientation and wind directions.

Sun orientation The Galfa orientation is not the best regarding to sun orientation as the eastren/southern/westren facade are exposed to more solar radiation than the other facades. but thanks to the service core on the west facade it affects directly the precentage of WWR and by editing some finishing materials it can be used as solar insolator in summer and solar mass in winter.

As discussed before in the service core part the precentage of WWR in the east is high (92%) with clear glazing which leads to conusme alot of energy in order to sustain the cooling and heating loads more than the obaque walls. Adding a solar chimney to that facade will leads to two benefits less clear glass (WWR 80%) without blocking the view towards Via G. Fara and it will help to cool the temprature through supplements wind-driven “Wind Core� inside the interior using Stack effect by heating more the air inside the chimney so it creates suction, pulling warm air from the internal rooms to the sky.

181

Fig:6.30 Adding solar chimney to the

eastren facade and the new EUI (Model/simulation by author according to the original drawing)

View is saved for the rooms thanks to the clear glass sidewalls

Opaque wall to heaten up the air to increase stack-effect

Fig:6.31 The new solar chimney should have clear glazing on the sides to save the view to the middle two rooms also an obaque dark finish on the front facade to help the fasten of air movement (Model/simulation by author according to the original drawing)

182

Fig:6.32 Clear glazing on the sides to save the view for the middle rooms Obaque dark finish on the front facade to act as a solar chimney

In summer & shoulder seasons Air is drawn naturally in through large operable windows then the 112m tall solar chimney uses stack effect and draws used air up and exhaust it out of the building

In winter Chimney closes, fans draw warm exhaust air down, and re-circulate it to warm the parkade.

The heat exchanger in the basement recapture heat and return it to south facade to preheat the the incoming air.

Depending of the efficency of the heat exchanger the bulilding might need to add Geothermal system

Wind direction Cross-ventilation draws the air through the rooms into the corridor where it is then exhausted into the solar chimney.

Vents located at the top of the chimney façade contribute to stack aiding in exhausting of air from the building.

Each office floor is cross-ventilated by drawing fresh air in from the rooms and exhausting it into the solar chimney (through vents in the raised floor “UFAD plenum system” since the chimney are separated from the corridors with internal walls).

Additional operable windows in east and west facades to increase the crossventlation inside the corridor adding cool air to aid stack effect within the chimney to exhaust the air from the building.

183

Fig:6.33 UFAD plenum system (these systems are modeled using a Displacement Ventilation principle requiring warm air to rise and stratify from the floor to the ceiling) (Graphics provided by center of built environment, UC-Berkeley)

06.2.4 Solar shading Shades can reduce HVAC energy use but the impact depends on other factors, such as window size and solar heat gains. The software simulation guides to provide shade on the building’s hot sides “westren & eastren facade” it will consume less energy especially if this shaders or recess can block the summer hot direct sun light but it will not block the daylighting and will allow winter direct sunlight.

In this case an external shade added with an offsett 720 mm (1/4 window hight) then resimulate the building to be the energy consumption much less and changed from 332 to 310 KWh/m2/yr.

In order not to affect the ditribution of day lighting because of the shade it is recomended to add upper light shelf with a reflective bright materials in the ceiling to extend the daylighting from 2 to 5 x window H.

With shade

1/4 Window H

720 mm

Without shade Summer solistic 68O

H= 2820mm

184

1/4 Window H

720 mm

Winter solistic 21o

Fig:6.34 Solar shades on the hot sides facade to break the solar radiation from Summer sunlight without blocking the winter ones (Model/simulation by author according to the original drawing)

06.2.5 Interactive facades To have a fixed shade it is good in a matter of less maintainance and expenses but the an interactive shades has other benifits. It controls solar shades on the facade and also in the interiors. not only but it controls also the internal day lighting diffusion and prevent glare using a small sensor attached to the window glass. Also it can be controlled by the user to be optimized on his visual and thermal comfortness, as he will find the instructions and recommendation digitally on a single screen in each room so he can control only his room as well as it will give esthetic appearance for the external facade.

30ยบ Summer solistic 68o 136o

30o

100ยบ 46% closed

185 5o 100o

Winter solistic 21o

180ยบ (Full) 67.5%

30o

5o 100o

Fig:6.35 Interactive solar shades on the bright facades to control automatically daylighting depending on time and manually depending on user visual and thermal comfort (Model/simulation by author according to the original drawing)

Torre GALFA Torre GALFA Technical drawings Technical drawings

06.2.6 Vegetation for cooling and natural ventilation Planting and landscaping will be added to torre GALFA not only for their ecological and aesthetic benefits, but also to cool the building. In this phase Planting will be introduced as vertical landscaping to faces courts of the whole buildings and also to be used as thermal insulator for the top floors (the panoramic restaurant). Plants absorb carbon dioxide and generate oxygen, benefiting the building and its surroundings In each corner of the building a winter garden has been specially designed 3 floors hight contains trees and water curtain GALFA and exhaust in the west facade, control of for fresh airTorre intake Technical drawings vertical sound transmission, and support of the exterior skin of the façade. Together with the double-skin façade,solar chimney and the winter garden comprises a key element of the tower’s natural ventilation strategy.

DN

UP

UP

DN

3rd floor plan 1:400 3rd floor plan 1:400

6th floor plan 1:400 6th floor plan 1:40

Typical floor plans Typical showing floor plans the changes showingofthe tempe cha air flow through airthe flow winter through garden the winter and thegarde sola UP

DN

3rd floor plan 1:400

186

ROOF 102900

ROOF 102900

30F 99620

30F 99620

29F 96340

29F 96340

28F 93060

28F 93060

27F 89780

27F 89780

26F 86500

26F 86500

25F 83220

25F 83220

24F 79940

24F 79940

23F 76660

23F 76660

22F 73380

22F 73380

21F 70100

21F 70100

20F 66820

ROOF 20F 102900 66820

19F 63540

99620 19F 63540

6th floor plan 1:400

Typical floor plans showing the changes of tempe air flow through the winter garden and the sola

30F

29F 96340

18F 60260

18F 60260 28F

17F 56980

17F 27F 56980

16F 53700

16F 26F 86500 53700

15F 50420

15F 83220 50420

14F 47140

79940 14F 47140

13F 43860

13F 22F 43860

12F 40580

12F 21F 40580 70100

11F 37300

20F 11F 66820 37300

10F 34020

63540 10F 34020

9F 30740

9F 30740 17F

93060

89780

25F

24F

23F 76660

73380

19F

18F 60260

56980

Fig:6.36 3 floor hight winter garden in the building corners comprises together with the double-skin façade,solar chimney a key element of the tower’s natural ventilation strategy.

(Model/simulation by author according to the original drawing) 8F 27460

8F 16F 27460 53700

7F 24180

15F 7F 50420 24180

6F 20900

6F 47140 20900

14F

13F 43860

5F 17620

5F 17620 12F

4F 14340

4F 11F 14340

3F 11060

3F 10F 34020 11060

2F 7780

2F 30740 7780

40580

1F 4280

G.F 0

37300

9F

8F 27460

1F 4280

7F 24180 6F G.F 20900

0

5F 17620 4F 14340

Conclusion Adopting green retrofitting systems in not only tall buildings, but many building types, faces a number of challenges beyond designing the most effective system for a particular site, program, building type and configuration. While there is the potential to greatly reduce energy costs, there is a perception that both construction costs and maintenance costs will be higher. When the potential “loss” of floor space through the use of double-skin façades and sky gardens or atria are factored in, it is not surprising that some developers consider the approach to be “too expensive” even when the long-term savings can be significant. However, in a mixed-mode building, European practice has suggested that 30 percent of yearly occupational hours utilizing natural ventilation will justify the mixed-mode strategy economically (Gonçalves 2010), but the perceived higher initial construction costs can be a difficult barrier to overcome.

What is increasingly becoming recognized in the whole sustainability equation is not just the savings through reduced energy/carbon bills, but the positive impact on occupants productivity through the creation of a higher quality (and perhaps more natural) internal environment. This will perhaps have the biggest bearing on the greater adoption of retrofitting for the tall buildings in the future, rather than the savings in energy consumption.

Perhaps the biggest challenge that green retrofitting faces is overcoming entrenched attitudes in both the building industry and among building occupants. Over the past 50 years or more the use of air-conditioning has become the norm in modern buildings and carries a quality status associated with its use. Overcoming this perceived quality barrier may be the single biggest hurdle that the true adoption of 100 percent natural ventilation in tall buildings faces. Even though the energy reductions and cost benefits are considerable, there is still a perceived quality and reliability issue with green retrofitting that pushes even the most environmentally conscious client As mentioned at the outset of this chapter, the true potential of delivering reduction of energy consuming by natural means will only be achieved through 100 percent reliance on green retrofitting. Retrofitted buildings, reduce operating energy for a portion of the year but it needs some time until thier progress to be on the point where clients feel confident in relying exclusively on them. It is only at that point when the industry will be able to say that the true potential of green retrofitting has been delivered.

187

188

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GreenBiz.com. Empire State Building Retrofit Lights the Way for New Projects, 2013. Available online: http://www.greenbiz.com/blog/2013/06/29/empire-state-building-retrofit-new-projects A Landmark Sustainability Program for the Empire State Building. Available online: http:// www.institutebe.com/InstituteBE/media/Library/Resources/Existing%20Building%20Retro fits/ESB-White-Paper.pdf Lockwood, C. Building Retro. Urban Land, November/December 2009. Available online: https://www.esbnyc.com/documents/sustainability/uli_building_retro_fits.pdf, p. 56 Johnson Control. Empire State Building, Performance Year 2 M&V Report, 2013. Available online: http://www.esbnyc.com/documents/press_releases/2013_ESB_Y2_ Full_Report.pdf Hampson, R. Empire State Building Goes Green, One Window at A Time. USA Today, 12 July 2010. Available online: http://usatoday30.usatoday.com/news/nation/environment/2010-07-12- empire-state-building-windows-green_N.htm Casey, T. “Pimp My Elevator” Retrofit Turns Clunkers into Energy Savers. Clean Technica, 19 February 2012. Available online: http://cleantechnica.com/2012/02/19/thyssenkrupp-eleveator- retrofit-harvest-energy-from-braking/ DeFreitas, S. Empire State Goes Big for Energy. EarthTechling, 8 February 2011. Available online: http://earthtechling.com/2011/02/empire-state-goes-big-for-green-energy/ Ivanova, I. Empire State Bldg’s Energy Savings Beat Forecast. Crain’s New York Business,24 June 2013. Available online: http://www.crainsnewyork.com/article/20130624/ REAL_ESTATE/ 130629951/empire-state-bldgs-energy-savings-beat-forecast Shaw, J. A Green Empire. Harvard Magazine, 2012. Available online: http://harvardmagazine.com/ 2012/03/a-green-empire Lockwood, C. Building Retro. Urban Land, November/December 2009. Available online: https://www.esbnyc.com/documents/sustainability/uli_building_retro_fits.pdf Meinhold, B. Sears Tower Going Green with $350 Million Renovation. Inhabitat, 2009. Availableonline:http://inhabitat.com/sears-tower-going-green-with-350-million-renovation/ Boniface, R. Renamed Sears Tower to Get Green Retrofit. AIArchitect, 21 August 2009. Available online: http://info.aia.org/aiarchitect/thisweek09/0821/0821d_sears.cfm Tobias, L. Why Taipei 101 Lifts Green Building, and Green Jobs, to New Heights, 2011. Available online: http://www.greenbiz.com/blog/2011/10/31/why-taipei-101-lifts-greenbuilding-green-jobs- new-height Knox, R.H. Case Study: Adobe’s “Greenest Office in America” Sets the Bar for Corporate Environmentalism. FMLink. Available online: http://www.fmlink.com/article.cgi?type= Sustainability&pub=USGBC&id=40625&mode=source Cammell, A. Adobe Systems’ Green Initiatives Generate Huge Savings. Tradeline, 29 July 2008.

Available online: http://www.tradelineinc.com/reports/2008-7/adobe-systems-green-initiatives- generate-huge-savings Tam, S.T. Skyscraper Green Retrofits Guide, 2011. Global Energy Network Institute (GENI). http://www.geni.org/globalenergy/research/skyscraper-green-retrofitsguide/Skyscraper-Green- Retrofits-Guide-FINAL.pdf Council on Tall Buildings and Urban Habitat (CTBUH). CTBUH 2012 Shanghai Congress— Patterson, “New Skins for Skyscrapers”, 2013. Available online: https://www.youtube.com/ watch?v=WS5Aczhoifs.

M. Flores, Building performance evaluation using Autodesk Revit for optimising the energy consumption of an educational building on subtropical highland climate, 2016. Page:7

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LOD Spec 2017 Guide, 2011. For Building Information Models. Available at https:// bimforum.org/wp-content/uploads/2017/11/LOD-Spec-2017-Guide_2017-11-06-1.pdf Ajla Aksamija, Tech Lab (Perkins+Will), 2012. BIM-Based Building Performance Analysis: Evaluation and Simulation of Design Decisions, Available at: https://pdfs.semanticscholar. org/973a/bbc6e6479bacafb2e0efc7cf86c1511e3840.pdf V. Ismet Ugursal, 2014, Building Performance Analysis and Simulation: We’ve Come a Long Way Available at: www.mdpi.com/2075-5309/4/4/762/pdf Daniel Overbey AIA, 2016, Building Performance Modeling Tools for Any Designer [webpage] http://danieloverbey.blogspot.com/2016/04/building-performance-modeling-tools-for.html S Goel, 2017,ANSI/ASHRAE/IES Standard 90.1-2016 Performance Rating Method Reference Manual Available at: https://www.pnnl.gov/main/publications/external/technical_reports/PNNL-26917.pdf E. Mazria, 2010,How we plan and design the built environment from here on out will determine whether climate change is manageable or catastrophic. Available at: http://2030palette.org/ K. FUHRMAN, 2016, AUTODESK UNIVERSITY, Insight 360: Energy Analysis . . . for Architects? Available at: http://au.autodesk.com/au-online/classes-on-demand/class-catalog/2016/revit/ar16137#chapter=0 2012,Torre Galfa, Past and Future - From the archive - Domus Available at: https://www. pnnl.gov/main/publications/external/technical_reports/PNNL-26917.pdf Laura Greco, Stefania Mornati, 2012,La Torre Galfa di Melchiorre Bega Architettura e Costruzione Cecilia Bolognesi, 2017,Il ritorno di un classico Available at: https://www.pnnl.gov/ main/ publications/external/technical_reports/PNNL-26917.pdf 2017,CLIMATE: MILAN Available at: https://en.climate-data.org/location/1094/

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List of Figures

195

Chapter 01 Environmental impacts of Skyscrapers energy consumption Fig:1.00 THE GLOBAL IMPACTS OF CLIMATE CHANGE (http://thebritishgeographer.weebly.com/the-impacts-of-climate-change1.html) Fig:1.01 Total building life cycle Buildings account for 40% of energy use worldwide (WBCSD).Energy used during its lifetime causes as much as 90% of environmental impacts from buildings (Journal of Green Building).Building operations consume more than 2/3 of all electricity (BuildingScience.com) Fig:1.02 Total life cycle impacts by life cycle phase for a prefabricated commercial building with average California energy use, the building as built (30% of power supplied by photovoltaics), and net zero energy (100% of power supplied by photovoltaics), in units of EcoIndicator99 points.

(EcoIndicator99 standards) Fig:1.03 Built environment impacts on its surroundings (source: The Green Skyscraper, Yeang, 1995) Fig:1.04 Bahrain World Trade Center wind blades (source: http://www.traveladventures. org) Fig:1.05 Apportionment of costs for a typical skyscraper (source: Hira, A, Paks, M, ’Design and Construction of cores of tall buildings- Achieving TQM through multi-disciplinary approach’ 1994) Fig:1.06 Reasons for retrofit (Source: Commercial and Institutional Building Energy Use Survey 2000 (CIBEUS) Summary Report, December 2003) Fig:1.07 CIS Tower (Manchester,UK) and Empire state tower (New York, USA) (source: solaripedia.com)

196

Fig:1.08 São Paulo, Brazil In a recent study, most urban areas were found to have smaller carbon footprints than their national averages. (source: the comparatively green urban jungle NY times) Fig:1.09 Land use, built form and plot ratio (source: The Green Skyscaper, Yeang, 1999, page 26) Fig:1.10 Projection of European cities with buildings over 100 meters in height by 2018 Note.

(The work based on data from The CTBUH Tall Building Database – The Skyscraper Center, retrieved on 25.05.2013 from http://skyscrapercenter.com) Fig:1.11 Projection of European cities with buildings over 100 meters in height by 2018 Note completed each decade with the individual building hight (The work based on data from The CTBUH Tall Building Database – The Skyscraper Center, retrieved on 28.12.2017 from http://skyscrapercenter.com) Fig:1.12 Projection of European buildings over 100 meters in function by 2018.

(The work based on data from The CTBUH Tall Building Database – The Skyscraper Center, retrieved on 28.12.2017 from http://skyscrapercenter.com) Fig:1.13 European high-rise buildings, 100 meters or taller, completed each decade and under construction: by function Note.

(The work based on data from The CTBUH Tall Building Database – The Skyscraper Center, retrieved on 25.05.2013 from http://skyscrapercenter.com)

Chapter 02 Building energy loads and performance analysis Fig:2.00

TYPICAL ELECTRICAL CONSUMPTION PATTERN IN BUILDINGS (Source: Thoughtful cooling workshop, Availabale at http://slideplayer.com/slide/10061176/)

Fig:2.01

Building’s average energy use Source: (cibse journal, Lighting control technologies and strategies to cut energy consumption )

Fig:2.02

Inforgraphic describe the relation between building’s energy use and thermal loads (source: Autodesk Building Performance Analysis and sustainability workshop, Building energy loads, sustainabilityworkshop.autodesk.com)

Fig:2.03

The building program determines whether internal or external loads dominate (source: Autodesk Building Performance Analysis and sustainability workshop, Thermal Loads, sustainabilityworkshop.autodesk.com)

Fig:2.04

Thermal loads from people doing different activities (source: Autodesk Building Performance Analysis and sustainability workshop, Thermal Loads, sustainabilityworkshop.autodesk.com)

Fig:2.05

When interpreting energy load charts, pay attention to whether the biggest heat losses and gains come from internal or external loads (source: Autodesk Building Performance Analysis and sustainability workshop, Thermal Loads, sustainabilityworkshop.autodesk.com)

Fig:2.06

Monthly heating and cooling load charts tell you where heat energy is being gained and lost (source: Autodesk Building Performance Analysis and sustainability workshop, heating and cooling Loads, sustainabilityworkshop.autodesk.com)

Fig:2.07

Energy intensity for US Buildings, by program type (source: U.S. Energy Information Administration, Commercial Buildings Energy Consumption Survey) Available at: https://www.eia.gov/consumption/commercial/reports/2012/energyusage/

Fig:2.08

Simulated Energy Intensities for an identical 4000 m2 office building in various EU countries (source: EECCA 2003)

Fig:2.09

Energy consumption by end use in the EU domestic and commercial buildings (source: EECCA 2007)

Fig:2.10

Example Internal Loads for Different Space Types note that this information can vary greatly based on the design and use of the space. Use more precise and specific estimates when available.

(Sources: United States Department of Energy (1 and 2), and Mechanical and Electrical Equipment for Buildings by Grondzik et al.)

Fig:2.11

Autodesk’s Insight energy analysis tool report building performance in terms of EUI and Annual Cost (Sources: Autodesk Building Performance Analysis and sustainability workshop, Measuring Building Energy Use, sustainabilityworkshop.autodesk.com)

Fig:2.12

Energy use intensity & 2030 challenge targets by building type (Source: CBECS 2003)

Fig:2.13

Energy use intensity by building floor space (Source: CBECS 2003

197

Chapter 03 Green retrofitting design goals Fig:3.00 Occupant’s comfort different elements (Source: Mena ashraf, 2017, Why Building Green Matters) Fig:3.01 Energy use breakdown for commercial buildings (Source: DOE, 2012) Fig:3.02 Ground heat conduction (Sources: redraw by the auther from Autodesk Building Performance Analysis and sustainability workshop, Passive Design Strategies for Heating, Cooling, & Ventilation, sustainabilityworkshop.autodesk. com) Fig:3.03 Sun radiation on the roof surface (Sources: redraw by the auther from Autodesk Building Performance Analysis and sustainability workshop, Passive Design Strategies for Heating, Cooling, & Ventilation, sustainabilityworkshop.autodesk. com) Fig:3.04 Energy passes through windows (Sources: redraw by the auther from Autodesk Building Performance Analysis and sustainability workshop, Passive Design Strategies for Heating, Cooling, & Ventilation, sustainabilityworkshop.autodesk. com) Fig:3.05 Insulated windows (Sources: redraw by the auther from Autodesk Building Performance Analysis and sustainability workshop, Passive Design Strategies for Heating, Cooling, & Ventilation, sustainabilityworkshop.autodesk. com) Fig:3.06 Opening placement (Sources: redraw by the auther from Autodesk Building Performance Analysis and sustainability workshop, Passive Design Strategies for Heating, Cooling, & Ventilation, sustainabilityworkshop.autodesk. com) 198

Fig:3.07 ASHRAE thermal sensation scale (Sources: Study on Sensor Fusion for Predicting Human’s Thermal Comfort Accounting for Individual Differences by Using Neural Network. omicsonline.org) Fig:3.08 Relationship between PMV and PPD indices (Sources: Study on Comfort modelling in semi-outdoor spaces. rehva.eu) Fig:3.09 Acceptable operating temperatures for naturally conditioned (Sources: ASHRAE 2004) Fig:3.10 Thermal manikins and comfort responses (Sources: The Center for the Built Environment (CBE) at the University of California at Berkeley (UCB) Fig:3.11 Glazing systems and winter and summer environmental conditions for meeting thermal comfort of occupants seated close to a window (Sources: Huizenga et al., 2006, Window performance for human thermal comfort) Fig:3.12 Light measuring units (Sources: Autodesk Building Performance Analysis and sustainability workshop, Daylighting Strategies, sustainabilityworkshop.autodesk.com)

Fig:3.13

Daylight design considerations (Sources:Aksamija, Ajla, (2014), Sustainable facades, Daylighting Strategies, page 153)

Fig:3.14

Diagram of light shelf performance in summer and winter.

(Sources: Ruck et al., 2000)

Fig:3.15

Diagram showing daylight facade strategies for locations with predominantly cloudy sky conditions (Sources:Ruck et al., 2000)

Fig:3.16

Diagram showing daylight facade strategies for locations with predominantly sunny sky conditions 11 (Sources:Ruck et al., 2000)

Fig:3.17

Applicability of different daylight facade strategies (Sources:Ruck et al., 2000)

Fig:3.18

Acoustic comfort factors for interior spaces (Sources:Aksamija, Ajla 2013, Sustainable Facades, ACOUSTIC COMFORT AND AIR QUALITY, p. 185

Fig:3.19

Sample of minimum outdoor air requirements for different programs (Sources:ASHRAE. (2007). ANSI/ASHRAE Standard 62-1-2007 Ventilation for Acceptable Indoor Air Quality.)

Fig:3.20

Avoiding mold by avoiding condensation points (Sources:Autodesk Building Performance Analysis and sustainability workshop, Indoor Air Quality, sustainabilityworkshop.autodesk.com)

Fig:3.21

Carbon monoxide, carbon dioxide, and volatile organic compound sensors at the Pacific Energy Center.

(Sources:Autodesk Building Performance Analysis and sustainability workshop, Indoor Air Quality, sustainabilityworkshop. autodesk.com)

Chapter 04 Green Retrofitting for Skyscrapers Fig:4.00

Benefits of green retrofitting (Sources:Mahtot Gebresselassie, 2014 Quick Facts About Green Retrofitting)

Fig:4.01

Global Warming Potential of New and Existing Building (Sources:Kheir Al-Kodmany, 2014 Green Retrofitting Skyscrapers: A Review P.01)

Fig:4.02

Energy-Efficient Refurbishment (KfW-Programme) (Sources:German Strategy for Energy-Efficient-Buildings & CO2-Rehabilitation Programme, P.7)

Fig:4.03

Menara UMNO in Penang, Malaysia the service core is placed along the southeast façade of the building (Sources:web, Emporis.com)

Fig:4.04

The Deutsche Messe AG Building in Hannover, Germany, ventilation tower rises by about 30 m above the northern access core (Sources: Herzog, T. (2000) Sustainable Height: Deutsche Messe AG Hannover Administration Building.

Prestel Press: Munich.)

Fig:4.05

Manitoba Hydro Place in Manitoba Canada, is a prime example of how a tall building’s orientation respond to both prevailing solar and wind (Sources:Kuwabara, B., Auer, T., Gouldsborough, T., Akerstream, T. & Klym, G. (2009) “Manitoba Hydro Place: integrated design process exemplar,” in Demers, C. & Potvin, A. (eds.) Proceedings of PLEA 26th International Conference. Les Presses de l’Université Laval: Quebec City, pp. 551–556)

199

Fig:4.06 Wing Walls on the southwest in Menara UMNO, Penang, Malaysia.

(Sources:Powell, R. (1998) “Vertical aspirations– Menara UMNO: Penang, Malaysia; architects: T. R. Hamzah & Yeang,” Singapore Architect, vol. 200, pp. 66–71) Fig:4.07 View into the west façade which doubles as a thermal flue in the GSW Headquarters building in Berlin (Sources: © Annette Kisling) Fig:4.08 KfW Westarkade plan showing the building’s directional, aerodynamic form and orientation allows fresh air to enter the exterior ventilation flaps of the double-skin façade so the offices are ventilated directly through this double-skin façade system (Sources: Antony Wood & Ruba Salib, 2013, Natural Ventilation in High-Rise Office Buildings ,P 124) Fig:4.9

Design considerations for optimal façade efficiency include advanced glazing materials, daylighting design, shading systems, super insulating materials like vacuum insulated panels, and building integrated photovoltaic technology.

(Sources: Mic Patterson, 2013, Incremental façade retrofits: Curtainwall technology as a strategy to step existing buildings toward zero net energy P. 05)

Fig:4.10 Single-skin façade of Highlight Towers in Munich is ventilated through operable panels behind perforated, fixed steel panels.

(Sources: © Murphy/Jahn Architects) Fig:4.11 View into the 1.4-meter-deep double-skin façade of Deutsche Messe AG Building.

(Sources: © MoritzKorn) Fig:4.12 Diagrams of the Pressure Ring façade in KfW Westarkade, Frankfurt.

(Sources: © Sauerbruch Hutton) Fig:4.13 A comparison of double-skin façades of diffrent case study buildings in this Technical Guide.

(Sources: Antony Wood & Ruba Salib, 2013, Natural Ventilation in High-Rise Office Buildings ,P 152) Fig:4.14 A. View for the west elevation B.View from one of the balconies.

(Sources: © T.R. Hamzah and Yeang) 200

Fig:4.15 A. Internal view of a six-story atrium in 30 St. Mary Axe London, UK – looking downwards onto the social meeting space at its base B. Section showing wind-flow through the inner areas of the building (Sources: © Nigel Young / Foster + Partners) Fig:4.16 Opening of the entire façade of of KfW Westarkade at the “tip” to enable through-flow of air on hot summer days. (Sources: © Jan Bitter) Fig:4.17 Typical office space in the Post Tower in Bonn, Germany, which enjoys high floor-to-ceiling heights due to its decentralized mechanical system.

(Sources: © Murphy/Jahn Architects) Fig:4.18 Showing the spatial configurations of openplan office spaces along the perimeter and cellular offices at the center.

A. Floor plan of Manitoba Hydro Place, Winnipeg B. Floor plan of San Francisco Federal Building (Sources: Antony Wood & Ruba Salib, 2013, Natural Ventilation in High-Rise Office Buildings ,P 114, P106)

Fig:4.19

Showing the spatial configurations of Cellular office spaces along the perimeter and open-plan office spaces at the center in the floor plan of Post Tower in Bonn, Germany (Sources: Antony Wood & Ruba Salib, 2013, Natural Ventilation in HighRise Office Buildings ,P 76)

Fig:4.20

Section view into 1 Bligh Street, Sydney showing the open ground floor to the outside and how it is naturally ventilated (Sources: Antony Wood & Ruba Salib, 2013, Natural Ventilation in HighRise Office Buildings ,P 134)

Fig:4.21

Floor plan and Section view for Commerzbank Frankfurt, Germany showing sky gardens can be used for a combination of air intake, extraction and induce ventilation in inward-facing offices.

(Sources: Antony Wood & Ruba Salib, 2013, Natural Ventilation in High-Rise Office Buildings ,P 134)

Fig:4.22

South atrium showing the sky garden as a six story-tall atria act at the building’s lungs drawing fresh air in and precondition it before inletting fresh air through the opaque spandrel panels on the inner façade to the under-floor distribution to the offices. “Manitoba Hydro Place, Canada” (Sources: © KPMB Architects/Eduard Hueber)

Fig:4.23

A.View of an interior office space, showing sliding windows with the wooden brise-soleil beyond in Torre Cube Guadalajara, Mexico. B. Detailed façade section through the wooden brise-soleil (Sources: © Estudio Carme Pinós / Lourdes Grobet)

Fig:4.24

A. View looking up at the RWE Tower in Essen, Germany with its ultra-clear glass façade. B. Interior view showing perforated aluminum blinds in the façade cavity (Sources: © ingenhoven architects )

Fig:4.25

A. Study on the Section of Liberty Tower of Meiji University Tokyo, Japan showing the stack effect in the central escalator void (the “Wind Core”) pulls air from the classrooms at each floor.

B. Study on the floor plan showing cross ventilation using Wind-induced (Sources: Antony Wood & Ruba Salib, 2013, Natural Ventilation in High-Rise Office Buildings ,P 44 )

Fig:4.26

In the interior of San Francisco Federal Building San Francisco, Wave-form exposed concrete soffits to increase surface area of the thermal mass.

(Sources: © Nic Lehoux)

Fig:4.27

A model for optimizing energy efficiency, sustainable practices, operating expenses and longterm value in existing buildings (Sources: A landmark sustainability program for the Empire State Building report P.1)

Fig:4.28

Cumulative metric tons of CO2saved over 15 years Net present value of package of measures (Sources: A landmark sustainability program for the Empire State Building report P.9)

Fig:4.29

Summary of key upgraded features of the Empire State Building (Sources:Kheir Al-Kodmany, 2014, Green Retrofitting Skyscrapers: A Review P.14)

Fig:4.30

Empire State Building (ESB) Performance Year 2. Reduction in ESB’s 2007 Baseline, Electric Utility Costs during Performance Period.

(Sources:Graph redrawn from Empire State Building, Performance Year 2 M&V Report 2013 P.15)

Fig:4.31

Empire State Building Performance Year 2. Reduction in ESB’s 2007 Baseline, Steam Utility Costs during Performance Period (Sources:Graph redrawn from Empire State Building, Performance Year 2 M&V Report 2013 P.15)

Fig:4.32

Empire State Building windows refurbishment process (Sources:Redraw in http://blog.lightopiaonline.com,2012)

201

Fig:4.33 Chicago’s Willis Tower opened in 1973. A modernization project aims to reduce energy use by 68 million kWh/yr. (Sources:Sara Beardsley, AIA, LEED AP, 2010, High performance buildings, P.59) Fig:4.34 Base building meter excluding tenant plug loads (Sources:Sara Beardsley, AIA, LEED AP, 2010, High performance buildings, P.60) Fig:4.35 Willis Tower’s current façade is approximately 60% glass and 40% anodized aluminum panels (Sources:Sara Beardsley, AIA, LEED AP, 2010, High performance buildings, P.62) Fig:4.36 The project team plans to add renewable energy to the building. through technologies such as photovoltaic panels and wind turbines would be visible to visitors (Sources:Sara Beardsley, AIA, LEED AP, 2010, High performance buildings, P.60) Fig:4.37 The tower successfully earned LEED Platinum certification—the highest level of achievement in the LEED system (Sources: Tobias, L. Why Taipei 101 Lifts Green Building, and Green Jobs, to New Heights, 2011.

Available online: http://www.greenbiz.com/ blog/2011/10/31/why-taipei-101lifts-green-building-greenjobs- newheights) Fig:4.38 In 2005, Adobe expanded its green missionand began pursuing the Leadership in Energy and Environmental Design (LEED®) certification for its San Jose headquarters (Sources:Adobe Systems incorporated platinum certification for leadership in energy and environmental design, P.01) Fig:4.39 Garage exhaust fan Labor to reduce operating times on garage supply fans cost a total of just $100. This modification in the fans’ programming resulted in savings of approximately $67,000 per year with no compromise to air quality (Sources:Adobe Systems incorporated platinum certification for leadership in energy and environmental design, P.06)

Chapter 05 Building Performance Analysis Fig:5.00 BIM uses a central model that can be extended for multiple purposes, including performance analysis Cost (Sources: Autodesk Building Performance Analysis and sustainability workshop, Building Performance Analysis (BPA), sustainabilityworkshop.autodesk.com) 202

Fig:5.01 BIM and BPA relation, and what types of analyses can be considered building performance analysis (Sources: Autodesk Building Performance Analysis and sustainability workshop, Building Performance Analysis (BPA), sustainabilityworkshop.autodesk.com) Fig:5.02 Typical Design Process of Buildings (Sources: Autodesk Building Performance Analysis and sustainability workshop, Building Performance Analysis (BPA), sustainabilityworkshop.autodesk.com) Fig:5.03 LOD and design process relation (Sources: Autodesk Building Performance Analysis and sustainability workshop, Building Performance Analysis (BPA), sustainabilityworkshop. autodesk.com) Fig:5.04 Level of Development and Building Performance Analysis Interaction Diagram (Sources: Autodesk Building Performance Analysis and sustainability workshop, Building Performance Analysis (BPA), sustainabilityworkshop.autodesk.com) Fig:5.05 Energy Analysis of the Audubon Center using Insight (Sources: Autodesk Building Performance Analysis and sustainability workshop, Solar Measurements & Strategies, sustainabilityworkshop.autodesk.com)

Fig:5.06

Insight building performance analysis feature (Sources: Screenshot from insight plug-in for Autodesk Revit, available at https://insight360. autodesk. com)

Chapter 06 Torre GALFA Green retrofitting Fig:6.00

3d Render showing how the envelope of Torre GALFA will be after applying the environmental solutions (Redraw by author according to the original drawing)

Fig:6.01

Floor plan of Torre GALFA showing the 6 wings of the load bearing structure (Redraw by author according to the original drawing)

Fig:6.02

Plan/Section/Elevation of the glass facade of Torre GALFA original design (Redraw by author according to the original drawing)

Fig:6.03

New functions by floor according to the new design (Redraw by author according to the original drawing)

Fig:6.04

Renovated elements by BG & K associate that directly affecting the energy consuming.

(Model by author according to the original drawing)

Fig:6.05

Typical floor plan configuaration changed from office building to be a hotel (Model by author according to the original drawing)

Fig:6.06

Triple Glazed panes in the curtain walls instead of two panes with a mechanical ventilation system works through the linear C/S louvers (Model by author according to the original drawing)

Fig:6.07

113 Sqm new core attached to the old one (source: Planimeter 2017)

Fig:6.08

Outward-facing bedrooms are ventilated directly through HVAC closed loop water system using a double-skin façade system to fasten the air speed (Model by author according to the original drawing)

Fig:6.09

Plan, 3d section & facade of the glass double facade used for the natuaral-ventiliation strategy showing how the closed loop water system works to change the internal tempreature through a hybrid system between a mechanical HVAC and stack effect in the double facade (Model by author according to the original drawing)

Fig:6.10

Every floor has a meter curtain wall in the south east facade. With this arrangement there is always a windward in each room which is ventilated through air moving from the closed loop water system.

(Drawings by author according to the original drawing)

Fig:6.11

The outward-facing bedrooms are ventilated directly through a double-skin façade system, with inwad HVAC closed loop water system. The inward-facing bedrooms are ventilated via rising stack buoyancy in the double facade,assisted by wind flowing from the HVAC system (Drawings by author according to the original drawing)

Fig:6.12

Wind Rose (source:Climater to travel)

Fig:6.13

Average Annual Temperature Profile (°C) (source:Climater to travel)

203

Fig:6.14 Sunshine hours (source:Climater to travel) Fig:6.15 Average Relative Humidity (%) and Average Annual Rainfall (source:Climater to travel) Fig:6.16 Energy Use Intensity and Energy Use cost (Model by author according to the original drawing) Fig:6.17 Energy Use Intensity compared with ASHRAE 90.1 benchmark Energy Use cost compared with ASHRAE 90.1 benchmark (Model by author according to the original drawing) Fig:6.18 Energy simulation for torre GALFA (Model by author according to the original drawing) Fig:6.19 EU Specific energy use (KWH/m2a) in the hotel buildings Source (D’Agostino, Zangheri and Castellazzi 2017) Fig:6.20 Solar shades analysis for (Model by author according to the original drawing) Fig:6.21 Shadow and shade for Torre galfa (Model by author according to the original drawing) Fig:6.22 Daylighting studies for Torre galfa in diffrent peak points for the sun direction and intensity (Analysis by author according to the original drawing) Fig:6.23 CFD modelling used to predict air flow pattern around Torre GALFA to understand the pressure diffrence on the buiding envelope (Analysis by author according to the original drawing) Fig:6.24 Hotel 3d view showing 1 floor splitted to zones and spaces to be a legend in the heating and cooling demands calculations (Analysis by author according to the original drawing) 204

Fig:6.25 Hotel floor plan splitted to zones and spaces to be a legend in the heating and cooling demands calculations (Analysis by author according to the original drawing) Fig:6.26 Heating and cooling loads in each space/zone/element (Analysis by author according to the original drawing) Fig:6.27 Climatic/design and energy use data for Torre galfa (Model by author according to the original drawing) Fig:6.28 Changing the position of service core from the westren to Eastren facade and the effect on the energy consumption (Model/simulation by author according to the original drawing) Fig:6.29 Changing of the core position will ban the connection with the old core and it close the external view for 4 main Hotel rooms (Model/simulation by author according to the original drawing) Fig:6.30 Adding solar chimney to the eastren facade and the new EUI (Model/simulation by author according to the original drawing) Fig:6.31 The new solar chimney should have clear glazing on the sides to save the view to the middle two rooms also an obaque dark finish on the front facade to help the fasten of air movement (Model/simulation by author according to the original drawing)

Fig:6.32

Clear glazing on the sides to save the view for the middle rooms Obaque dark finish on the front facade to act as a solar chimney (Model/simulation by author according to the original drawing)

Fig:6.33

UFAD plenum system (these systems are modeled using a Displacement Ventilation principle requiring warm air to rise and stratify from the floor to the ceiling) (Graphics provided by center of built environment, UC-Berkeley)

Fig:6.34

Solar shades on the hot sides facade to break the solar radiation from Summer sunlight without blocking the winter ones (Model/simulation by author according to the original drawing)

Fig:6.35

Interactive solar shades on the bright facades to control automatically daylighting depending on time and manually depending on user visual and thermal comfort (Model/simulation by author according to the original drawing)

Fig:6.36

3 floor hight winter garden in the building corners comprises together with the double-skin façade,solar chimney a key element of the tower’s natural ventilation strategy.

(Model/simulation by author according to the original drawing.

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Technical drawings (list of drawings)

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Sheet 01 Torre GALFA Original design

1. Floor plan of old design of Torre GALFA

2. Section of the glass facade of Torre GALFA old design

3. Plan/Elevation of the glass facade of Torre GALFA old design Sheet 02 Torre GALFA Refurbishment

1. Typical floor plan configuaration

2. 113 Sqm new core attached to the old one

3. Double-skin façade system to fasten the air speed

4. Triple Glazed panes in the curtain walls

5. New functions by floor according to the new design Sheet 03 Torre GALFA Cross ventilation studies

1.Typical floor plan showing the cross-ventilation through a double-skin façade system 1:200

2.Vertical section A-A showing the cross-ventilation through the double-skin Facade 1:500

3. 3d section of the glass double facade Sheet 04 Torre GALFA performance analysis 01

1. Energy simulation for torre GALFA

2. Energy Use Intensity and cost

3. Energy Use Intensity and cost compared with ASHRAE 90.1 benchmark

4. Solar shades analysis for external mass

5. Shadow and shade studies for Torre galfa Sheet 05 Torre GALFA performance analysis 02

1. CFD modelling used to predict air flow pattern around Torre GALFA

2. Daylighting studies for Torre galfa in diffrent peak points for the sun direction and intensity Sheet 06 Final design plan and Elevations

1.Typical floor plan 1:200

2.South Elevation 1:500

3.East Elevation 1:500

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Sheet 07 Final design plan and sections with environmental studies

1.3rd floor plan 1:400

2.6th floor plam 1:400

3.HorizontalSection A-A 1:500

4.Transversal Section B-B 1:500 Sheet 08 Final design 3D environmental studies

1.3d shots showing the winter garden inside Torre GALFA

2.HorizontalSection A-A 1:500

3.Transversal Section B-B 1:500

describing the Air flow inside the building

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