Dissertation SED Eashita Saxena

PASSIVE DESIGN STRATEGIES IN LONDON OFFICE BUILDINGS

DISSERTATION BY EASHITA SAXENA AA_SED-2015-16

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AA 2015-16 MSC. SUSTAINABLE DESIGN ARCHITECTURE

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ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE GRADUATE SCHOOL PROGRAMMES COVERSHEET FOR SUBMISSION 2015-16 PROGRAMME: SUSTAINABLE ENVIRONMENTAL DESIGN (SED) TERM: 4 STUDENT NAME(S): EASHITA SAXENA NO. OF WORDS: 18,448 (This doesn’t include referencing, acknowdgements).

SUBMISSION TITLE: PASSIVE STRATEGIES IN LONDON OFFICE BUILDINGS COURSE TITLE: DISSERTATION COURSE TUTOR: MARIAM KAPSALI SUBMISSION DATE: 16/09/2016 DECLARATION: “I certify that this piece of work is entirely my/our own and that any quotation or paraphrase from the published or unpublished work of others is duly acknowledged.”

Signature of Student(s): Date: 16/09/2016

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ACKNOWLEDGEMENTS I would like to acknowledge my gratitude towards my tutor Ms. Mariam Kapsali, with whose guidence and support I was able to complete my dissertation. Her support during the tutorials was very benificial. I would like to thank Mr. Herman Calleja, who really helped me with all my software and technical support.. I would also like to thank Mr. Simos Yannas for all the encouragement and for letting me become a part of Architectural Association.for the academic year 2015-16. I would like to thank Architectural Association and all the SED teaching staff for their support and for providing me with such a wonderful experience during this year. I want to especially thank my parents and my brother without whose constant support my dissertation project and my journey at Architectural Association would have not been possible. In the end I would like to thank my collegues and friends who helped me during my dissertation.

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ABSTRACT In recent years, there has been a certain increase in the amount of CO2 Emissions which has adverse effect on the environment and all of the life forms. One of the major cause of this increase is High energy consumption in buildings (as buildings are a major contributor for it).

Office buildings are a major contributor towards the higher energy consumption and CO2 emissions due to its dependence on certain elements. Also, due to Climate Change, there is a high risk of overheating in Office Buildings in London which increases the dependence more on systems like Air Conditioning at the same time, most offices are not benefited with optimum daylight levels, which can affect their productivity. These challenges can be tackled effectively by the use of Passive design Strategies for Office Buildings. Use of Passive Strategies such as Night Ventilation can help reduce the dependence on Air Conditioning when combined with High Thermal Mass which helps in reducing the loads and using certain strategies such as shading elements can help in achieving optimum daylight.

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TABLE OF CONTENTS Introduction 1) Background 2) Research objectives 3) Research methodology

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1 Chapter 1: Theoretical Background 1.1 Introduction: why office buildings?

1.2 Energy consumption of office buildings‌ 1.3 Different types of offices, workspaces, advantages/disadvantages 1.4 Passive techniques

16 16 18 20

2 Chapter 2: Built Precedents 2.1 Pool innovation center 30 2.2 Woodland Trust Headquarters 33 2.3 BRE Garston 37 2.4 Conclusion 41 3 3.1 3.2 3.3

Chapter 3: Climatic Analysis Current climatic conditions Comfort conditions Future climatic conditions (2050)

44 47 49

4 Chapter 4: Fieldwork 4.1 Introduction 54 4.2 Location 54 4.3 Features about the building 55 4.4 Interviews and measurements 56 4.4.1 Spot measurements 58 4.4.2 Data Loggers 60 4.4.2.1 Working space 61 4.4.2.2 Meeting rooms 62 4.5 Conclusions 63 5 Analytical work 5.1 I urban studies 5.2 Daylight analysis 5.2.1 Base case: 50% Glazed 5.2.1.1 Light shelves 8

67 71 72 73

5.2.1.4 Light-shelves with blinds 76 5.2.1.5 Overhangs with blinds 77 5.2.1.6 Comparison among different...

78 5.2.2 Comparison among different strategies‌ 81 5.2.3 Shading devices for different orientations 84 5.3 Thermal analysis 95 5.3.1 Base case 96 5.3.2 Strategies for improved case 98 5.3.3 Future scenario 102 5.3.4 Window to wall reductions 103 5.3.5 Glazed facades 106 5.3.6 Conclusions 108 6

Research outcomes and applicability

Appendix

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INTRODUCTION 1.1 Background:

The burgeoning global industrial economy has become ever so dependent on energy sources so as to be needing to exploit the natural resources. Rapid population growth and higher immigration into large and mid-size cities are putting tremendous pressure on the cities’ resources. Per a report by Yau and Hasbi (2013) the national energy consumption stands at 34% in the UK and 40% in the European Union (report by Ekins and Lees, 2008). This is estimated to grow 34% year on year over 20 years (Hassam NC, Hughes BR, Abdul-Ghani S, 2012). It is estimated that buildings are responsible for half of all the global generation of carbon dioxide. Additionally, 47% of all global energy gets used by buildings (Richard Roggers, Beating the Heat, 2016). We can reasonably deduct that heating, ventilation and air-conditioning (HVAC) accounts for a pretty chunky amount of energy consumption in buildings (which is in fact 60% or more of the total energy consumption in buildings, Mardiana - 2012).

Our day to day lives have become excessively dependent on using (for example) air conditioning, and acknowledging that this will continue to grow the world energy demand in 2020 can be estimated to be 50 to 80% higher than 1990 levels (as suggested by Omer (2008) in a study of World Energy Council). There is an urgent need to acknowledge the current global trends of rising energy consumption, and the energy crisis, and plan a step wise reduction in energy consumption. There have been many attempts both at the policy level and from the ground up where entrepreneurs have been finding low cost energy efficient solutions leveraging technology to harness natural resources. However more needs to be done as the energy needs are growing faster than the solutions can be implemented and scaled up to a big population. A way to overcome the energy crisis is to essentially use passive strategies to cool the building and low-energy methods for low consumption of energy.

In the UK, summers have typically been getting warmer due to climate change, which means keeping windows open no longer provides any cooling. Buildings in UK would need a radical design change to cope with the gradual climatic shift (Beating the Heat, 2016).

Currently there is an increased dependence on mechanical cooling devices however this isn’t advisable since it increases energy consumption and engenders CO2 emissions which accelerate climate change. In 2008, the Climate Change Act attempted to introduce the first long-term framework to reduce CO2 emissions by 80% by year 2050, taking the data 1990 data as baseline. It has been estimated that 45% of the UK’s total carbon emission are derived from buildings, 17% of which form non-domestic buildings (Department for Communities and Local Government, 2009. Great Britain. Climate Change Act 2008: Elizabeth II. Chapter 27. (2008) London, The Stationery Office Department for Communities and Local Government (2008). Zero carbon for new non-domestic buildings consultation on policy options. Accessed 24th May 2016).

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Hulme el al (2002) projects that peak summer could see up to 7°C higher temperature than today in 2080. There is a drastic design shit needed since in the 90s the office buildings were designed keeping in mind lower temperatures, cooling loads, and illumination. Some of the typical issues with most office buildings from the 90s are: 1.

Overheating during summers (caused due to the ever increasing temperatures / changing climate across the year) 2.

Insufficient lux/daylight levels inside buildings which increases usage of artificial lighting (could also be due to excessive construction around, and excessive glare designs from the 90s - which also causes ineffective performance levels) 3.

Higher cooling loads (temperature inside is now higher than before) There is a need for more energy efficient solutions which potentially reduce energy consumption across the building (Mardiana, 2011).

The buildings also need to fall into the specifications of the comfort band; 1.

Optimum daylight for users: buildings should achieve optimum daylight levels 2.

Thermal comfort for users: thermal comfort is an important consideration and since it helps keep the energy consumption low Typically heating and cooling loads are used to keep the temperature within the comfort zones. Multiple factors such as building materials, infiltration, illumination etc. correlate and help optimise the comfort zones. In order to optimise to the comfort band, several natural and artificial design changes would need to be made.

1.2 Research Objectives: There would be multiple objectives that would attempt to be achieved through this paper: 1.2.1 Optimise energy performance of office buildings in London and Indoor Environment to create comfortable environment for the staff.

1.2.2 Establish guidelines for London offices and influence future offices design as well.

1.2.3 Identify and analyse the effect of various parameters that can enhance the thermal performance of offices such as Natural Ventilation, Building Envelope and Daylight (Orientation of window and shading devices).

1.2.4 Analyse the impact of these strategies on heating and cooling loads 1.2.5 Analyse the impact of these strategies on energy consumption and CO2 emissions.

Additionally, underlying hypotheses would be tested across: Natural Ventilation, Optimum Daylight, Proper Building Envelope which plays a substantial role in reduction of energy consumption.

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1.3 Research Methodology:

A methodical literature review, fieldwork and analytical work were carried out through computer simulations.

The next chapter focuses on the office buildings in London, and highlights the evolution over years in terms of design, building components and their impact on energy consumption and carbon dioxide emissions. It also highlights the different kinds of workspaces and the different factors which impact performance of office buildings from an environment and comfort point of view.

Next, the focus shifts to climate analysis of London based on comfort conditions.

Next, 3 built precedents are studied to understand the functionality and performance of various office buildings. It also delves deeper into the strategies adopted by architects to improve performance and helps benchmark the energy consumption.

In the fifth chapter, fieldwork in a particular London office building is discussed, which highlights functionalities of various spaces in office buildings. The analysis helps in identifying the problems of (air conditioned) office buildings and the factors affecting their visual and thermal performance.

The penultimate chapter (Six) analyses thermal and daylight performance of workspaces which was formulated through the analysis of the fieldwork and literature review and implementing various strategies along with the impact of occupancy, different definitions of equipment loads to provide thermal and visual comfort in the workspace of the office building.

The final chapter summarises the design guidelines and the applicability of research for design of shading devices, night ventilation and its safety and adaptability in other building typologies such as open plans, its applicability for future scenario for office buildings.

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CHAPTER- 1 THEORETICAL BACKGROUND

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1.1. Introduction: Why office buildings?

Buildings generate half of the world’s CO2 and consume 47% of all energy. Attempting to solve design issues could potentially address a huge global issue, hence the opportunity to make an impact is huge.

Additionally, with industrialisation moving into smaller cities, office buildings would make a high contribution to the CO2 and energy.

Figure. 1.1.1 Energy Use Breakdown Source:Energy consumption by sector and building energy mix, 2010 There have been several measures introduced in Europe, U.S. and Japan to make buildings more efficient. EU has mandated all new buildings with a ‘nearly zero energy’ design. Japan has a similar ambition- for all new public buildings to be “zero emissions” by 2030. The U.S. Energy Independence and Security Act of 2007 wants all new Federal facilities to be ‘zero net energy’ by 2030. Navigant Research reports that the global ZEB market is expected to grow from $629.3 million in 2014, to $1.4 trillion by 2035.

1.1.a Energy consumption of office buildings in UK/EU and CO2 emissions.

Global governments have made energy consumption and efficiency a core part of their strategy to reduce carbon emissions (Figure 1.1.2). There is a huge social and legislative support for energy efficient buildings and policies aimed at promoting energy efficiency through incentives, building codes, and prescriptive measures are being introduced. The next generation of energy efficient technologies such as LED lighting are better performers and come at lower prices. Building automation and controls softwares are leveraging data and analytical capabilities to identify a range of low cost performance improvements. Per Navigant Research, the global market for energy efficient building products and services could grow from $307.3 billion in 2014, to $623.0 billion in 2023.

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Figure. 1.1.2 Energy Efficiency Score Card Source:2014 international energy efficiency scorecard In the commercial services space, the energy consumption grew by 68.4% from 1973 to 2000. Artmann, Manz and Heiselberg in the paper ‘Climatic potential for passive cooling of buildings by night-time vent in Europe’ (2007) observe that Europe has seen a reduction in heating demand and a concurrent surge in cooling demand over last few decades. They see passive cooling as a promising technique, x more so in moderate or colder climates of Central and Northern Europe. An overview of the climatic potential for night-time cooling in Europe has been highlighted on a map (Fig 1.1.3). It can be seen how Northern European countries can benefit from a high cooling potential of 120–180 Kh in even the hottest months.

Fig. 1.1.3 Passive Strategies used Source: sustainabilityworkshop.autodesk.com/buildings/night-purge-ventilation

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1.2 Different types of offices, workspaces, advantages/disadvantages and their applicability In the UK, there are typically four types of office spaces: Type (1) Naturally ventilated, or cellular: This is a shallow-plan building, typically small (100 to 3000 m2, building depth 10 to 20m) and converted from a residential accommodation. It has a domestic approach, with individual windows, local light switches and heating controls, however lower illuminance levels. Occupants are able to use the building per their needs hence energy consumption, is lower.

Type (2) Naturally ventilated, open plan often purpose-built (500 to 4000 m2): This is largely open-plan, with some cellular offices and special areas. Illuminance levels are better and hours of use are better than those of cellular offices. Office equipment typically finds high demand and due to high usage by occupants, lights and shared equipment are generally used for longer time periods.

Type (3) Air-conditioned (2000 to 8000 m2): This has similar occupancy and planning to Type (2), however with a deeper floor plan. Windows are often tinted or shaded, which further reduces daylight. This type is used more often.

Type (4) Air-conditioned, prestige National or regional head office, or administrative centres (4000 to 20000 m2): This type is often purpose-built, or refurbished to high standards. The plant is typically run longer to suit a much more diverse occupancy. Office equipment usually includes catering kitchens, and air-conditioned rooms for computers and other equipment.

Fig. 1.2.1 Typical Building Types in UK (BRE,2000) Source: BRE (2000). Comfort without air conditioning in ,--refurbished offices_ an assessment of possibilities. New Practice Case Study 118. Building Research Establishment.

Table 1.2.1 Requirements for Different Types of Workspaces Source: Office Spaces

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Table 1.2.2 Requirements for Different Types of Meeting Spaces Source: Office Spaces

While discussing about the office buildings, it is also important to understand the different types of spaces that are present there Table1.1.1-1.2.2. The 2 tables shows compilation of such spaces. In the 1990’s, importance on allotment on small cubicle space per person was considered as 1 of the standard while designing whereas today or in the future, use of flexible workspaces has gained more popularity due to its advantage, that many people can use a particular space at different times and for different activities.

Collaborative working With the five elements of Agile Working becoming increasingly relevant in workplace design, collaborative working has become a major requirement for many businesses trying to create a much more productive area for their teams.

Multi-purpose areas The average cost of office space in London exceeds the CBD of Paris and New York’s 5thAvenue by £170 per square foot office space – space optimisation becomes important.

Some research shows that on average 77% of private workspaces are unoccupied throughout a normal working day and a huge 60% of traditional workstations are left unused.

1.4.5. Difference in U values over the years While talking about the passive strategies for better design and lower energy consumption of the buildings, 1 important element that comes to mind are the U values of the materials, which reflects the amount of heat that a building component can absorb. It is important as it helps in deciding the type of material to be selected depending upon the heat gain or loss requirement of the building.

Previously, in 1990’s the U values of the materials used to be quite high such as according to building regulations of 1991, The U values were as follows:  External wall 0.45 W/m²K.  Exposed Floor 0.35 W/m²K.  Roofs 0.2 W/m²K. Windows, roof windows, glazed roof lights and glazed doors 3 W/m²K. Part L of building regulations (conservation of fuel and power) would. Prevent certain forms of construction by setting limiting standards (i.e. maximum U-values) for building elements.  External wall 0.18 W/m²K.  Floor 0.13 W/m²K.  Roofs 0.13 W/m²K.  Windows, roof windows, glazed roof lights and glazed doors 1.4 W/m²K. Table 1.2.3 shows how these U values will change in the near future, which helps us to understand the type of fabric to be considered for the construction.

Table 1.2.3 Overview of 2005 and 2030 office building Source: eceee.org

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1.3. Passive techniques Passive systems and technique interventions reduce heating and cooling requirements of the building by managing solar contribution. Some of the interventions are the use of thermal mass and application of passive cooling techniques, used to improve indoor thermal comfort.

Table 1.3.1 Air Infiltration Rates for the Buildings Source: Cibse Guide A

Reducing infiltration: Assuming a baseline in 2005 with high infiltration rate of 1 ach, it is unlikely that a high level such as this will be seen by 2030 with simple draught-proofing. This value drops to 0.5 ach, with heating reduction as well as improving the internal comfort conditions (i.e. reducing draughts) Table 1.3,1 shows the different infiltration rates for different types of building fabrics.

Fabric and glazing measures: We can assume that by 2030, insulation measures will be carried out to reduce heating loads in offices. Calculating the annual carbon emissions reduction is a non-trivial task as, although savings are made the heating season, the (electric) cooling load during the summer is likely to increase.

Thermal adaptation of occupants: The heating and cooling temperature set points are often assumed to be static, often 218C and 238C for simulations. In reality this is an unlikely case, with the response of an occupant highly variable and condition dependent on previous days/weeks (i.e. the occupant can become used to gradually increasing temperatures).

Night time ventilation: The general approach when the infiltration of a building has been reduced is to subsequently improve or optimize the ventilation schedule. It is often very effective to do this at night. Day-time ventilation will only provide a cooling effect if external air temperature is cooler than internal temperature.

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Figure 1.3.1 Shows the effect of night Ventilation in Europe Source: Climatic potential for passive cooling of buildings by night-time ventilation in Europe Artmann, N., Manz, H., and Heiselberg, P. (2007) Figure 1.3.1 helps to understand the potential for the effective use of Night Ventilation has in Europe. Energy performance analysis is typically conducted to calculate and analyse annual energy consumption, identify the most cost effective insulation and glazing, and find anything else which can optimise building design for efficient energy usage. Simulations typically vary local environmental conditions, and involve thermal, daylight, and airflow modelling.

Internal temperature of the building: Typically, changing small power and lighting has quite a noticeable effect on temperature. With smaller standby loads overnight, and less heat being trapped in from the previous day, the temperature prior to the start of the working day (i.e. before 0900 h) is several degrees cooler than the 2005 baseline.

Accounting for the effects of the 2030 climate and fabric/glazing, it is predicted that, at this point, the office will have significantly lower internal temperatures (and lower cooling loads) than the 2005 baseline, because of the effect of small power and lighting changes. Considerable cooling would still be necessary, however, with the rise in internal gains during the day.

This final scenario is now similar to the situation prior to introducing the lower infiltration rate. Such a strategy might be recommended when, after improving air-tightness for reducing heating loads during the winter months, the summer performance of the building is detrimentally affected.

1.4. Effect of internal heat gains on the office building: Tertiary sector buildings and office buildings are heavy users of energy, thus have the potential to significantly reduce energy consumption. To achieve this there needs to be a rethinking of the building design process which leads to an optimization of the building’s energy demand and good indoor environmental quality conditions.

Equipment impact: Equipment calculations are based on the power demand performance combined with a few other parameters (Table1.4.1): Usage: a % value of the number of devices per person Night-time shutdown: the % of devices which are switched off at night Occupied utilisation: based on the level of building utilisation. For example, if the building is only 45% utilised, then only 45% of devices will be used during the day.

It assumes that all electrical energy is converted into heat and 80% is convective and 20% radiative.

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AA 2015-16 MSC. SUSTAINABLE DESIGN ARCHITECTURE Table 1.4.1 Equipment Energy USe Source: Cibse Guide A

1.4.7. High Heating and Cooling Loads in London Office Building Few changes can be applied to impact reduction in cooling loads in London (excerpt taken from the Low-carbon Tech 2009 Jenkins paper): Small power and lighting: For both small power and lighting, the 2005 baseline and future 2030 scenarios are defined to account for potential improvements to these technologies. In case of small power, this includes the use of low-energy displays (low-power LCD screens), efficient energy management (switching off equipment during the night and weekend), and personal computers. Future lighting technology also points to large energy savings, with the use of light-emitting diode (LED) lighting having the potential to replace current triphosphor fluorescent lighting. Estimations for the savings along with the expected change in peak internal heat gain.

Inefficient equipment and lighting also play a huge part towards the size of cooling (and heating) loads.

Radically increasing insulation for a non-domestic building can sometimes have a detrimental effect. A building with high internal heat gains can lose this unwanted heat through fabric heat loss and infiltration.

Introduction of draught proofing, consequence of radically changing the building fabric, reducing the infiltration rate of non-domestic buildings can be an effective measure when aiming to reduce building heating consumption. An airtight, high density office is more likely to have an overheating problem than a poorly airtight equivalent which, although having a higher heating consumption, will have warm internal air displaced by cooler external air at a greater rate.

Acoustics One of the most effective ways to reduce noise in the office is with acoustic panelling and booths, which ties in with our previous point looking at the increase Intech and the fact that staff are looking at alternative places to pitch themselves and get on with their task at hand.

The most common way of battling intrusive noise levels is to apply the ABC Theory – Absorb, Block, and Cover.

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1.7. Overheating problem in current situation as well as in the future.

Overheating has many different definitions depending upon the type and use of the building in question.

These can take the form of the number or percentage of occupied hours greater than some temperature (comfort band temperature range) (e.g. >28°C), or not to exceed a set limit (e.g. >32°C), or the difference in temperature between outside and inside to be less than some limit (e.g. <5°C when external temperatures >20°C). These limits all have the same objectives - to improve thermal comfort within the building, to avoid heat stress on the occupants and maintain productivity.

The main sources of heat in a building are: •Warm air via infiltration or ventilation (if it’s warmer outside) •Solar gains, both through windows and heat transmission through building fabric •Heating system (if controls are poor, this should ideally not be a source of overheating) •Lighting •Equipment, computers, printers, TVs, fridges etc.

•Metabolic heat (people and animals) Buildings provide an interface between the outdoor environment, which is subject to climate change, and the indoor environment, which needs to be maintained within a range that keeps the building occupants safe and comfortable, and is suitable for key processes taking place.

In London, the mean monthly heat island intensity increases by about 30% from 1.5 K in the winter to 2 K in the summers. The intensity of a heat island increases as the wind speed drops.

Energy Efficiency—Depending on the office size, local climate, use profile, and utility rates, strategies for minimizing energy consumption involve: 1) reducing the load (by integrating the building with the site, optimizing the building envelope decreasing infiltration, increasing insulation, etc.); 2) correctly sizing the heating, ventilating, and air-conditioning systems; and 3) installing high-efficiency equipment, and appliances.

Reducing our demand for heat is a highly cost-effective way of cutting emissions from buildings. We can achieve this in three ways: ● by increasing thermal efficiency through better insulation; ● by increasing the efficiency of heating delivery systems; and ● by improving our heat usage (by avoiding heating unoccupied spaces through use of heating controls, or meters).

Where we need to be? ● Reducing waste heat to cut emissions ● Minimise avoidable heat loss and unnecessary heating ● Reduce overall demand to curtail short-term peaks in heating demand Overall, our buildings demand over 500 TWh annually, around 75% of total UK heat demand and a third of all UK energy demand, by continuing to deploy established measures like cavity wall insulation at scale, and supporting newer fabric technologies like solid wall insulation, we could reduce heat demand by up to 27 TWh by 2020 and may also constrain demand for cooling in summer months.

How we get there?

By reducing heat loss from our buildings; the UK has some of the oldest and least thermally-efficient building stock in Europe.

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Fabric efficiency: Glazing: (Double glazing can reduce a building’s heat demand by over 10%) Insulation: In a solid-walled building, insulation has a comparatively larger effect on reducing heat loss than cavity wall insulation in a cavity-walled building.

Other measures including floor insulation, can be applied to prevent heat loss from buildings and insulated doors. Even basic measures to reduce draughts can have a material effect, reducing heat loss by up to 5% while increasing comfort.

Reducing Average Internal Temperatures: User behaviours also affect heat demand in buildings. This includes how heat is used and distributed in properties, and the interactions between occupants, heating systems and the building itself.

In a larger building, a well-designed solar system can satisfy 30-40% of the annual hot water load.

Solar heating (passive): ● Collection of solar energy through properly-oriented, south-facing windows ● Storage of this energy in ‘thermal mass’ comprised of building materials with high heat capacity such as concrete slabs, brick walls, or tile floors ● Window specifications to allow higher solar heat gain coefficient in south glazing.

Sizing of glass areas, insulation values, shading, and mass will depend on climate. Higher solar savings contributions will require greater amounts of glazing and mass.

Based on climate: the passive solar design of skin-load dominated buildings might include: ● Orienting more windows to the south ● Shading to avoid summer sun ● Incorporating thermally massive construction materials ● Providing properly sized and installed insulation ● Downsizing heating, ventilating, and air conditioning equipment.

Fabric and glazing improvements have a small positive effect on cooling load reductions, with insulation (generally) being detrimental but with a beneficial improved glazing. Allowing for a change in occupant behaviour and increased comfort temperatures during warm conditions has a striking effect for an 80% less cooling requirement than the baseline.

Some shading techniques: Shading can take many forms; Trees – these provide shade in summers and allow passive solar heating of spaces in winters. Trees also actively cool their surroundings through evapotranspiration of water from their leaves.

Smaller / less windows – this can restrict heat entering a space however makes it feel dark and enclosed, resulting in larger lighting energy usage. Since windows have a higher U-value than the wall they are reducing heating loads considerably.

Roof overhangs and external shades – these provide shading of windows and external walls. Ideally the overhang needs to be sized to provide shading during the hottest months and to a lesser extent during the cooler months. Roof overhangs typically only provide shade for the top floor, however extra shades can be applied to the building to shade other floors.

Window recesses – the wall thickness have a profound effect on the amount of daylight that enters a room.

This effect should be considered as a means of limiting solar gains in summer.

Brise Soleil – These can be mounted horizontally or vertically and perform a similar job to external shades.

They’re available in fixed and adjustable variants, the angle of the fins is chosen to shade the space at certain times of day / year. Adjustable versions can be controlled by a building management system (BMS) to control lighting and overheating levels.

Solar films –These can take the form reflective or coloured versions, the difference is largely aesthetic, although the colour of transmitted light has to be considered as it alters the internal environment. They do have the downside that there will be reduced day lighting potentially leading to higher artificial lighting usage in the winter months.

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Design causes of overheating Some of the reasons for overheating are thought to be modern building fabric standards that aim to keep buildings warm in colder climates. The House Builder’s Association have been reported as saying that ‘the ever exacting standards’ of Building Regulations Part L cause overheating by stipulating airtightness levels that are too high.

Overheating may be caused by a single predominant factor or as a cumulative effect of different factors. These include:  Solar radiation passes through glass and heats internal surfaces, which re-radiate long wave infra-red radiation that cannot pass through glass. This is known as the greenhouse effect.  Double-glazed windows reduce heat losses through conduction.  Increasingly high levels of insulation reduce heat transmission across the building fabric.  The activities of occupants such as cooking, bathing, showering all generate heat. Electrical appliances generate heat when in use.  Occupants generate heat proportional to their activity level.  If a site is in close proximity to airborne noise, pollution or odour from busy roads, railways or industrial sites, occupants will be reluctant to open windows and so heat will accumulate inside.  Urban heat island effect is primarily caused by the replacement of natural surfaces with hard impervious surfaces that are generally dark and absorb large amounts of solar radiation. Urban hard surfaces are significant in the built environment in the form of roads, paved areas, rooftops and so on.  Buildings oriented with south facing glazing may accumulate high levels of solar gain.  Overheating problems may be contributed by heat gain from boilers, hot water storage and distribution and other building services systems.  Increasing levels of airtightness can reduce the amount of ‘fresh’ air entering a building.

How to deal with overheating  Orientation and footprint can be designed to minimise solar gain and maximise opportunities for cross ventilation, stack ventilation and so on.  High-performance glazing such as low-e glass, smart glass and so on can reduce heat gains. Smart glazing can be manually or automatically adjusted to control the amount of light, glare or heat that passes through. Whilst the price is decreasing it is still a very expensive option and as such is most likely to be found in commercial developments.  Adjustable blinds can allow some internal control over solar gains.  External shading such as canopies, louvres and shutters may help to prevent overheating. Intelligent facades can give control over climate exposure.  Glazing ratio: Large expanses of glazing increase solar gain and make a building more susceptible to overheating. However, large windows also admit natural light. Glazing ratios try to achieve an equilibrium between these two positions.

Preventing overheating Due to the complexity of heat transfer and dynamics of heat storage, no single solution can be considered as solving all cases of excess heat. Added to this the appropriateness of many solutions will differ between different buildings as for example, the cost, planning restrictions, etc. may make some solutions on some buildings inappropriate or prohibitively expensive. The following should be considered: Insulation The provision of additional thermal insulation to the walls and loft (roof) will help prevent solar gain. However, external wall insulation is problematic for solid wall construction, particularly where the dwelling abuts the pavement.

External protection can be provided by a brise-soleil or an awning. These are most suited for South facing windows and walls, giving protection from high level sun. Vertical shading is more suited to windows facing East or West, giving protection from low level sun.

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Means of ventilation Ideally, ventilation should be passive, so avoid the use of additional energy needed for fans or air conditioning. An excessive reliance on fans or mechanical systems is energy usage, which means they are not a viable option for dwellings occupied by low income households.

Occupier behaviour Limiting heat gain and reducing indoor temperatures requires the active participation of the occupiers which includes use of shading from the sun, and understanding appropriate day and night ventilation.

Occupiers can gain relief and cooling where there is a cool room, such as a North-facing room, within the dwelling (or building).

Natural ventilation Day ventilation by opening windows is only useful where the outdoor temperature is lower than the indoor.

Ventilation at night with high air change rates is important to ensure residents can sleep and heat built up over the preceding days.

Typical background ventilation rates in UK dwellings are approximately 0.5 air changes per hour (ach). Many mechanical ventilation systems have an ability to provide a boost level of ventilation. On site measurements have revealed that this may be an increase of 25 to 50%. Doubling the ventilation rate to 1 ach would be very unusual for a typical mechanical system. Purge ventilation is considered to be at least 4 ach, i.e. eight times greater than the normal background ventilation rate, which no mechanical system could achieve unless specifically designed to do so.

Air movement As mentioned above, as well as air temperature, the risk from overheating is also affected by other factors, including air movement. Air movement helps the body cool principally by evaporation, depending on relative humidity.

There have been studies and a recent review on the effectiveness of fans to provide air movement during heat waves and, a recent study involving eight healthy males, found fans were effective during hot and humid periods (Ravanelli et al, 2015). However, fans do not replace the requirement for adequate ventilation.

Comfort cooling Installing a comfort cooling system is, in terms of solving an overheating problem, a fail-safe solution - a system large enough could be installed. Refrigeration systems are not 100% reliable and the impact on occupants of a failure must be considered. The wider impact on the local environment must also be considered as heat rejected from one household will tend to increase the air temperature in the local micro-environment, increasing the risk of overheating in adjacent households.

Assessing potential effectiveness of remedial measures Where the source of heat gains is less clear, and cannot be largely removed, the effectiveness of reducing gains combined with increasing heat rejection must be assessed. This requires that the assessment method captures the dynamics of the thermal processes within the dwelling and its surrounding micro climate.

A Comparitive Table (Table 1.7)for these strategies is given below:

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Table 1.7 Summerising the Strategies Source: designingbuildings.co.uk/wiki/Preventing_overheating

It can be concluded by saying that some makor problems were highlighted such as High Energy Consumption due to High Loads. Due to risk of Over heating due to Climate Change, considerable amount of cooling loads are also increasing. To tackle these challenges, there are certain strategies that can be applied.

These Strategies can help reduce the Energy consumption and can help in keeping the temperatures within comfort hence keeping the occupants satisfied.

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CHAPTER- 2 BUILT PRECEDENTS

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The objective to study built precedents was to understand the factors and strategies that are important in reducing the energy consumption.

Figure 2.1.1 View of Pool Innovation Centre Source: cornwallinnovation.co.uk 2.1 Pool Innovation Centre The Pool Innovation Centre, designed by AHR global is a new 3 storey office building, built in 2010 (Fig-3.1).

It has facades with ample amount of glazing and has an area of around 2245m². It is an L-shaped building open plan office building and has a car park is right next to the office building in front of the main road.

They have used Smart Lighting for the interiors. Externally, the building presents a typically robust Cornish face, with local materials such Delabole slate and Cornish Western Red Cedar sitting alongside glulam bris-soleil and glazed-in photovoltaic cells which helps in making the building more sustainable. For Carbon Emissions reduction, Sedum roof have been used, which helps in keeping the environment good and at the same time helps in preventing overheating. It was awarded the BREEAM Excellence Award as it uses 60% less energy than conventional office buildings due to its design strategies. (cornwallinnovation.co.uk).

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One of the significant feature which helps the building to make it more energy efficient and creates more comfortable environment for the office goers as well as helps in regulating the energy consumption is the use of Natural Ventilation in the building, for the use of Natural Ventilation, low level open able windows were used as well as automatic windows with manual override which makes it a more adaptable option for the occupants. Apart from this, they also use passive stack effect for enhancing the Natural Ventilation in the building. Along with the daytime Natural Ventilation through the windows, night ventilation is also used for keeping the environment of the office cooler during the summers as was recorded by Innovate UK, 2014.

For the heating, biomass boiler is used as the main heating system which is supplemented by condensing gas-fired boilers. Besides this, Rain Water harvesting system has been actively implemented in the project. As recorded by Carbon buzz, in terms of energy consumption, the building is performing better than the initial estimated energy consumption during the design stage.

Design Stage Energy Consumption: 140.0 kWh/m2/yr Actual Energy Consumption: 91.4 kWh/m2/yr The breakdown of the energy usage can be seen in Figure 3.1.2.

After the completion of the project (2010), Post Occupancy Evaluation was conducted in 2014 by Innovate UK, which highlighted some of the problems that are faced by the occupants, such as, The problem with the glare had been highlighted which is due to the presence of high amounts of glazing in the facades. The Night Ventilation is not used and working properly due to the heat loss is not attained properly which can increase the risk of overheating and reduces the internal air quality as well.

/m2 /m2

/m2 /m2

/m2

/m2 /m2

/m2 /m2

Figure 2.1.2 Breakdown of Energy Consumption Source: carbonbuzz.org

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Figure 2.1.3 View of Pool Innovation Centre Source: cornwallinnovation.co.uk

Figure 2.1.4 View of Pool Innovation Centre Source: cornwallinnovation.co.uk

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Figure 2.1.4 Woodland Trust Headquarters Source: fcbstudios.com

2.2 Woodland Trust Headquarters The office building is located in Grantham, Lincolnshire. It was designed by Feilden Clegg Bradley Architects.

The project completed in 2010. It won RIBA Regional Award East Midlands in 2011. It has an area of 2,728m2. The office building is designed to accommodate a staff of 200. The design team and the client’s aim was to create a highly innovative and sustainable building within a market rate budget, and to achieve a BREEAM Excellent rating (e-architect.co.uk, 2011). It was essential we reflected the core values of the Woodland Trust in its headquarters, both in terms of aesthetics and in the inherent environmental stance they want to convey. Therefore we utilised the natural beauty of wood, with unique sustainability measures’’ says Matt Vaudin, Partner at Feilden Clegg Bradley Studios (bkstructures.co.uk, 2016).

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162mm Cross-Laminated Structural Panel

160mm Wood fibre insulation 22mm Wood Fibre Sarking Board 38mm Tanalised Softwood Battens and Counter-battens 22mm Untreated European Larch Cladding

Figure 2.1.5 Cross Laminated mber Detail Source: Innovateuk.com The materials used for the construction were: Pre-cast Concrete, Cross Laminated Structural Timber and Steel. Cross Laminated Structural Timber Fig 2.1.5 is very beneficial for whole life cycle costs of the building as it needs nearly no maintenance and it is resistant to chemicals. The panels made from cross laminated structural timber helped in removing approximately 897.6 tons of CO2 from the atmosphere.

Suspended rectangular concrete slabs were used which were connected by 2.4 metre wide cross laminated timber roof panels. The concrete slabs helps in increasing the thermal mass of the building which is crucial for absorbing the heat from the office during the day and recycling it at night with the help of night time ventilation. For this purpose, concrete radiators were used which covered upto 50% of the ceiling area on ground, first and the second floors as can be seen in (Figure 2.16). These radiators are rectangular in plan which are fixed on the underside of the timber frame (klhuk.com, 2010).

The office is on a green field site and the architects have tried to incorporate the surroundings in the building design. Staff and visitors are welcomed through a central garden space planted with birch trees, which encourages a range of interactions by providing both an informal meeting area and a place for eating lunch outdoors. The building ascends in a spiral and thus makes a dynamic transition from landscape to building.

Section through the Concrete Radiators

Figure 2.1.6 Concrete Radiators Source: klhuk.com 34

Open Spaces

Ground Floor Plan

First Floor Plan

Figure 2.1.7 Floor Plans showing openspaces Source: fcbstudios.com

The officeâ&#x20AC;&#x2122;s performance was evaluated by Innovate UK in 2014 which helps to understand how the building is performing post occupancy. It was found that the Occupant satisfaction has been good, especially at bringing the people together as the building is designed in such a way that it has many spaces which encourages interaction among the people as can be seen in Figure 2.1.6.

There are three places, where light and air can move between the floors: the cutaway atrium to the north, the stairwell in the middle, and an opening between the entrance and the reception desk. Mixed-mode ventilation and cooling in the meeting rooms in the south wing. Roof lights above the second and third openings allow sunlight to enter the core of the building and be reflected from surfaces in common areas, without causing glare at workstations.

Windows which are double glazed low E gas filled, which have U values of 1.4 and 1.2 W/m2 K have been used. The building has good daylight levels due to presence of roof lights, atrium as well as due to it being an open plan office building. The control over the task lighting have been recorded as simple to use and is performing well in the workspaces. Occupancy sensing light sensors are also employed which saves unnecessary usage of artificial light. It was suggested that some blinds would be used for the prevention from glare (Innovate UK, 2014).

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CIBSE TM46 BENCHMARK

Heating: 36KWH/m2 Domestic Hot Water: 11KWH/m2 Cooling: 1.5 KWH/m2

Lighting: 23KWH/m2 Power: 50 KWH/m2 Unallocated Energy: 54 KWH/m2

Figure 2.1.8 Energy Consumption Source: Carbonbuzz.com Windows which are double glazed low E gas filled, which have U values of 1.4 and 1.2 W/m2 K have been used. The building has good daylight levels due to presence of roof lights, atrium as well as due to it being an open plan office building. The control over the task lighting have been recorded as simple to use and is performing well in the workspaces. Occupancy sensing light sensors are also employed which saves unnecessary usage of artificial light. It was suggested that some blinds would be used for the prevention from glare (Innovate UK, 2014).

The figure shows the energy consumption of the building. It suggests that through the use of the strategies the architects have manage reductions in heating and cooling substantially (Carbonbuzz.com).

Figure 2.1.9 View of the Openspace in Office Courtyard Source: fcbstudios.com 36

2.3 BRE Garston The building was constructed in 1996. The building has an area of 1350 m2. It is an L shaped (Figure 2.1.10) open plan office building. It has consideration for flexible spaces. This building was also designed by Feilden Clegg Bradley Architects. The project received a BREEAM ‘Excellent’ rating, achieving the highest score.

This office building provides a model for offices for the 21st century. Innovative and environmentally advanced, it demonstrates the way for the future based on a platform of new low-energy targets. It is the first building to use, as part of the design brief, the Performance Specification drawn up by the Energy Efficient Office of the Future (EOF) Group, a partnership between BRE, manufacturers, designers, fuel utilities and other building professionals. The building has achieved the highest possible BREEAM rating. The building aims not only to provide a working office with low energy consumption in use, but also to serve as a large-scale experimental facility for evaluating various innovative technologies. (BRE Projects) The objectives for this building were: • avoiding or minimising the use of air-conditioning • maximising the benefits of the building fabric to reduce the heating and cooling loads • minimising the use of artificial lighting while actively exploiting daylight • Applying the appropriate level of automatic and user controls.

The designers aimed at reducing energy consumption through the strategies mentioned above at the same time they considered recyclability of materials important and hence, 96% of the materials used were recycled and used such as recycled aggregate for concrete superstructure (UK’s first building to do so).

Apart from this bricks, gypsum and wood block floors were also recycled (fcbstudios.com).

Figure 2.1.10 L-Shaped Plan Source: fcbstudios.com

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Figure 2.1.11 View of BRE Garston Source: fcbstudios.com The main environmental features of the project are its Ventilation Strategy.

The most striking feature of the building when seen from the south side is the five distinctive ventilation shafts running up the faรงade (Figure 2.1.12). These form a key part of the energy-saving natural ventilation and cooling system, they act as solar chimneys which works on the principle of stack effect.

Working rather like a greenhouse, the summer sun shines into the glass-fronted shafts, warming the air inside. This warmed air naturally rises out of steel shafts and causes air from inside the building to be drawn through to replace it. On a breezy day the movement of air across the tops of these chimneys increases the stack effect.

In addition to this, to reduce the risk of overheating, night ventilation is also used which is bolstered by the use of curved hollow concrete floor slabs which adds the thermal mass in the building. The concrete used helps in cooling the building by cooling the incoming air by absorbing heat from it (projects.bre.co.uk/ envbuild/).

Figure 2.1.12 Section for Ventilation Strategy Source: fcbstudios.com 38

Cold water is supplied by a 70-meter-deep bore hole where the temperature is a constant 10° Celsius. This cold water is used in heat exchangers to chill circulatory water. The floor can also then use the water to store “coolness” from the night for the next day. In the winter time, the water is heated by condensing gas boilers that are 30% more efficient than traditional boilers by recovering heat lost in flue gases. All heating and cooling systems are managed by the BMS system (Greenarch Case study).

For the purpose of daylight, the building’s glazing is optimized by a movable louvered exterior shading system that is designed to allow maximum day lighting at the same time minimizing glare Figure 2.1.132.1.14. The louvers have high reflectivity. The movement of the louvers is controlled by BMS system but it can also be operated by the occupants of the building. The louvers are designed in such a way that they are not a barrier in terms of visual connectivity (Greenarch Case study).

TL5 fluorescent lights that consume less energy than traditional tubes. Power for the lights and other systems is supplemented by a building-integrated photovoltaic array, as the power of the cells is directly linked to the computer, so the people can stay aware as to how much power is being consumed.

Figure 2.1.13 VSection showing the concept for Shading Devices Source: fcbstudios.com

Figure 2.1.14 View Showing Shading Devices

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Figure 2.1.15 Energy Consumption Source: Carbonbuzz.com The energy consumption shows that the passive strategies used are very successful in reducing the energy consumption of the building (Figure 2.1.15) From a report of Post Occupancy review, it was found that the building has (Riain, et al): • Excellent summer thermal environmental control, • Good standards of relative humidity, indoor air quality and ventilation; • Good levels of daylight, although these are slightly lower than expected; • An energy performance that exceeds good practice, but needs optimisation, • There is a scope for improvement for airtightness in the building and Better controls can be provided to the occupants. ` •

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CONCLUSION: From the study of these 3 offices, some of the questions which are put on are dealt with such as to what extent can energy consumption be reduced with the use of passive strategies. It also helped in informing the research which are the strategies that are successful in providing comfortable environments to the occupants. Importance of night ventilation with high thermal mass was one of the factors which was highlighted in all the 3 projects.

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CHAPTER- 3 CLIMATIC ANALYSIS

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3.1 Current Climatic Conditions

LONDON

51.5074° N

London is the capital of England. London is characterized by its fairly cold climate and overcast sky with regular light precipitation throughout the year. It has quite cold summers with mild winters.

The climate is characterised as temperate marine, which suggests relatively mild changes between seasons and rare extreme weather phenomena. In general, the winters are chilly and summers moderately warm, which can be beneficial in terms of applying natural ventilation strategies.

0.1278° W

LONDON

Fig.3.1.1 Location of London This chapter focuses on the climate analysis of London and it explains the comfort conditions for office buildings in London climate. Fig.3.1.1 shows the location of London followed by its coordinates.

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TEMPERATURE

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WINTER

SPRING

SUMMER

AUTUMN

1.6 kw/m2

35

1.4 kw/m2

30

1.2 kw/m2

25

1.0 kw/m2

20

0.8 kw/m2

15

0.6 kw/m2

10

0.4 kw/m2

5

0.2 kw/m2

0

JANUARY

FEBRUARY

MARCH

APRIL

MAY

JUNE

JULY

0.0 kw/m2 AUGUST SEPTEMBER OCTOBER NOVEMBER DECEMBER

Fig-3.1.2 Historical weather data with comfort band (after SED course tools and Meteonorm 7

The weather data (Fig- 3.1.2) shows that the average maximum temperature in summer is =20째C and minimum =15째C (approximately). In Winter the average maximum temperature is 8째C and minimum =3째C (approximately).

The prevailing winds (Fig-3.1.3) are mostly South-west in all seasons, with an average of 3.25 m/s for the whole year and maximum speed of 10.43m/s during the whole year.

Fig-3.1.3 Annual Wind Speed for Current Climate

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The figures 3.1.3-3.1.4 shows solar radiation and precipitation pattern for London based on historic data from Meteonorm for the year 2015 which reflects current conditions for the climate.

The global solar radiation in summer averages around 400W/ m2 with a maximum of 1200W/ m2. In winters the average is around 100 W/m2 with maximum of 400W/m2.

Fig- 3.1.3 Solar Radiation Source: Meteonorm 7

Precipitation in summer averages around 55mm. In winters the average precipitation is around 70mm.

Figure 3.1.5 shows Cloud Cover for every week of the year.

It shows typical days of different months like warm sunny day, Warm cloudy day, cold sunny day and cold cloudy day.

These conditions helps in informing us about the climatic conditions which will also help in comparing and analysing the climatic conditions of the future (which is discussed in the coming

Fig- 3.1.4 Precipitation Pattern Source: Meteonorm 7

Fig- 3.1.5 Cloud Cover in Different Months Source: satelight 46

3.2 Comfort Conditions Occupied Hours: 9:00-18:00

Fig- 3.1.6 Adaptive Comfort Band ESEN15251: 2007 Source: SED Spreadsheet

For the purpose of this research, the adaptive thermal comfort band is calculated using the EN 15251:2007 & CIBSE Guide A which considers that users can acclimatize according to recent climatic conditions. Specifically, the following formula has been used to define thermal neutrality: Tn= 18.8 + 0.33 Trm (Trm= Weighted running mean of the daily mean external temperature) A comfort band of span of 6K temperature range was considered to define the limits of comfort. The running mean constant was taken as 0.8 . The value 0.8 is recommended by EN15251 and CIBSE for offices in UK and represents about 1 week adaptation time.

The occupied hours for the graph (Fig. 3.1.6) was considered from 9 am to 6 pm as these the official office timing which is considered in the basecase (Chapter 5).

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AA 2015-16 MSC. SUSTAINABLE DESIGN ARCHITECTURE PSYCHROMETRIC CHART FOR CURRENT SCENARIO Comfort 820 hours

Fig. 3.2.2 Psychrometric chart showing the comfort zone according to ASHRAE Standard 55 and Current Handbook of Fundamentals Mode The Psychrometric chart (Fig. 3.2.2) suggests for the current climate 820 hours are under the comfort zone. It also suggests some strategies that can help in achieving comfort such as : For Passive solar heating face most of the glass area south to maximize winter sun exposure and design overhangs to fully shade in summers.

Provide double glazing (Low-E) on west, north and east but clear on south for maximum passive solar gain.

Heat gain from lights, occupants, and equipment greatly reduces heating needs so keep building tight, well insulated.

Tiles or slate floors provide enough surface mass to store winter daytime solar gain and summer nighttime cooling.

Natural Ventilation can store night time cooling in high mass interior surfaces. (Climate Consultant)

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3.3 Future Climatic Conditions (2050)

TEMPERATURE

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WINTER

SPRING

SUMMER

AUTUMN

1.6 kw/m2

35

1.4 kw/m2

30

1.2 kw/m2

25

1.0 kw/m2

20

0.8 kw/m2

15

0.6 kw/m2

10

0.4 kw/m2

5

0.2 kw/m2

0

JANUARY

FEBRUARY

MARCH

APRIL

MAY

JUNE

JULY

0.0 kw/m2 AUGUST SEPTEMBER OCTOBER NOVEMBER DECEMBER

Fig-3.3.1 Future Climate with comfort band (after SED course tools and Meteonorm

The analysis of climate (Fig-3.3.1) for the future (2050) suggests that the average maximum temperature in summer is =22°C and minimum =16°C (approximately). In Winter the average maximum temperature is 10°C and minimum =3°C (approximately). It shows that the average mean temperature in summer will be higher by 1-2° C while in winter it is expected to reduce by 1-2°C, this phenomenon is due to climate change and urban heat island effect.

The prevailing winds (Fig-3.3.2) are mostly South-west in all seasons, with an average of 3.25 m/s for the whole year and maximum speed of 10.43m/s

Fig-3.3.2 Annual Wind Speed for Future Climate

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Fig-3.3.3 Solar Radiation of Future Climate Source: Meteonorm

These figures (3.3.3-3.3.4) shows the expected solar radiation and precipitation for the year 2050.

There are some minor changes in terms of Solar Radiation with slight reduction in Global radiation in 2050 in comparison with Historical Conditions.

The days for precipitation doesnâ&#x20AC;&#x2122;t change much but thereâ&#x20AC;&#x2122;s is an increase in the precipitation that can be seen in the year 2050 in comparison with Historical Conditions.

Fig-3.3.4 Precipitation of Future Climate Source: Meteonorm

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PSYCHROMETRIC CHART FOR FUTURE SCENARIO Comfort 626 hours

Fig. 3.3.5 Psychrometric chart showing the comfort zone according to ASHRAE Standard 55 and Current Handbook of Fundamentals Mode The Psychometric chart (Fig. 3.3.5) for the future suggests that lesser temperatures are falling within comfort band when compared to the current case.

Thus, it is important to consider adaptive design strategies to mitigate the effects of climate change.

The increase in outdoor temperatures adds to the risk of overheating during the future summers.

The design research aims to cope with increasing outdoor temperatures and solar radiation while still maintaining comfortable levels within the spaces.

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CHAPTER-4 FIELDWORK

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4.1 Introduction: For understanding the functionality of the office buildings in London, the problems of the office buildings, problems faced by the occupants in the offices, it was realised that it will be beneficial to study a real building so fieldwork was conducted in BDSP London office.

Fig. 4.2.1 Location and Nearest Transportation

CHAPMAN BDSP

Fig. 4.2.2 Building Heights in the Area around the Office

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4.2 Location The office is located in Central London in Kirby Street (Figure 4.2.1). The Office has its proximity to the tube stations â&#x20AC;&#x201C; such as Chancery Lane and through a good network of buses due to its proximity to Holborn. The land use of the buildings around the BDSP office is all commercial, with office buildings on either side of the office. The buildings around are 3 to 4 storied high (Figure 4.2.2).

4.3 Features about the Building Figure 4.2.3 and 4.2.4 shows the views of the office. The building in which BDSP has a Ground + 5, with the office located at the 4th and the 5th floors. The office is a deep plan office building equipped with Central Air Conditioning in both the floors. 1250m2 of the 4th floor is – and it has an occupancy of 103 people whereas the 800m2 of the 5th floor is – and it has an occupancy of 65 people. Both the floors has glazed facades on 3 sides of the floors which are accompanied by terraced balconies on both the floors.The windows are fixed in the facade with some glass doors which leads to the terraced area outside.

The building doesn’t comprise of any systems such as BMS for automatically maintaining proper temperatures in the building. They use artificial lighting in the workspaces which can be controlled by the occupants through the usage of switches.

The office has 5 working days with occasional meetings over the weekend.

The official working timings are from 10:00 AM to 5:30 PM as can be seen from Fig. 4.2.5, with some people coming earlier and some people leaving until late. Lunch time is between 1-2pm. But most people eat at their desks. Normally, whosoever arrives the first in the office, turns on the lights while at night, a person from maintenance arrives to close all the lights at 9:30 PM. But some people such as in the engineering department are not in the office many times as they are gone for some meetings or that they work from home at times.

Fig. 4.3.1 Building View from Outside

Fig. 4.3.2 Building View from Inside

Fig. 4.3.3 Occupancy Schedule

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The office building was built in 1990’s.

According to the constructions during the 1990’s, the following U values of the building components were used such as: For window construction, Double Glazing was used. The office has low thermal mass owing to the usage of carpets in the workspaces on both the floors. Along that, in the ceiling as well as in the internal walls, the use of gypsum board suggests the office has low thermal mass. According to an energy assessment report of the building (mentioned by an occupant), some spaces of the building are at a significant risk to overheating.

Quatations from the Interviews

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4.4 Interviews In order to understand proper functioning of the office, the most valuable information was given by the occupants: people working in the office.

Interviews were conducted during the fieldwork which highlighted the main issues of the office. The first interview was done with the manager of the office (Lisa Hudson). The second and the third interview was done with the occupants working in the architectural department (Herman and Antonio). Some of the learnings highlighted through the interviews are: •Temperature fluctuation: The main problem recorded by all the 3 people during the interview was that there is a big problem with the heating and the cooling. Sometimes, it is very hot and sometimes it was quite cold, depending on the temperatures outside and the solar radiation.

•Air conditioning: Despite being an air conditioning office, improper functioning working of the air conditioning has been recorded due to temperature differences.

•Lack of Control: There are no sensors in the office to keep a check on temperatures. Occupants can’t regulate the temperatures in the space through the use of sensors etc. They simply have to be adaptable in terms of clothing, if it gets too cold they were more layers (and vice versa).

•Acoustics: External and internal noise was recorded. If the doors are open, there’s a lot of external noise that can be heard within the office.

At the same time, there’s a lot of internal noise, weather it is by people talking around or by the printing machines etc, so if there is a task that needs full concentration, it becomes difficult to find a quiet place.

•Daylight: They use artificial lights extensively which are almost on all the time as reported during the interview with Antonio. The reason behind it would be that the building is a deep plan office building, the light is unable to reach the center part where the workspaces are present, as the depth passes the depth according to the passive zone: 6-7 meters for the height of 3m of the glazing.

•Glare: Problem of glare was highlighted, the reason behind which is the presence of glazed facades, making the temperature to rise in the space, making it warmer at the same time visual discomfort is caused by the glare.

•Ventilation: There is no ventilation strategy used, sometimes it gets very hot they open the windows, but the building authorities ask them do to do so at times as it is an air conditioned building as recorded

by Antonio during the interview. There is no provision for night ventilation in the building.

•Good elements: There were some architectural features appreciated by the occupants such as the terraced balconies, the curved wall which starts from the reception on the fourth floor and leads to the main office space: work spaces. They also appreciate the blinds that are now present in the building.

The interviews with the occupants were very valuable as they helped in identifying main issues of the office, namely, •temperature fluctuations (due to improper functioning of the air conditioning), •improper daylight distribution in workspace and dependence on artificial lighting and •Noise: indoor and outdoor noise.

These issues results in thermal discomfort of the occupants followed by visual discomfort due to improper daylight and it can be difficult to concentrate at a few tasks due to noise. All these factors affect the occupant’s productivity.

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4.4 Measurements: In order to understand the thermal performance of the office, two set of spot measurements and data logger readings for a week were recorded.

4.4 a)

Fig. 4.4.1 Outdoor Conditions during first Spot Measurements

Fig. 4.4.2 Air Temperatures on fourth floor

Fig. 4.4.3 Air Temperatures on fifth floor 58

Spot measurements

The spot measurements were taken on days with different weather conditions.

The first set of spot measurements were taken on 8th June 2016 between 11 AM to 1 PM. Outdoor conditions suggested that it was a sunny day with Illuminance of 50.4KLux followed by outdoor temperature of 26°C having wind velocity of 0.8 m/s and relative humidity of 47.3% (Fig. 4.4.1).

For the evaluation of indoor conditions, The temperatures measured on various spots, of which temperatures were in the range 25-28°C Figure 4.4.2- 4.4.3 with the wind condition from 0-0.5m/s.

with relative humidity between 38-54% as can be seen in Figure-4.4.4 and 4.4.5.

Illuminance close to window were quite high- and the ones taken around the workspaces cannot be taken as accurate as the artificial lighting was on as can be seen in Fig 4.4.6-4.4.7.

The indoor temperatures are higher than the outdoor temperature, and the temperatures are varying on different spots on both the floors, temperatures in the workspace are higher than the temperatures around the window, which could be due to high internal heat gains in the workspaces due to usage of equipmentâ&#x20AC;&#x2122;s and the lights which is also affecting the relative humidity on these spots.

Fig. 4.4.4 Relative Humidity on the Fourth Floor

Legend for Relative Humidity

Fig. 4.4.5 Relative Humidity on the Fifth Floor

Lights On

Fig. 4.4.6 Lux Levels on the Fourth Floor

Fig. 4.4.7 Lux Levels on the Fifth Floor

Legend for Illuminance

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The second set of spot measurements were taken on 13th July 2016 between 3:30 to 4:30 PM. It was lightly raining at the time while the measurements were taken. . Due to light rains, the illuminance level was 930Lux with quite high wind velocity of 1.7m/s and relative humidity of 35.7%.

In terms of indoor temperatures, there was a variation between 25.6-29.4°C at different spots on the 4th floor.

The illumination level measured around the window was- whereas the workspaces were under the influence of the artificial lighting.The relative humidity is in the range 41.7-49% on the floor.These measurements were taken at 4pm.

On the 5th floor, the average temperature was 27°C, there isn’t a major variation in terms of temperature: 27-27.3°C as can be seen in the appendix. But there is a major difference in the range of relative humidity: 36.4-58%.

The temperatures were higher than the outdoor temperatures, the spot measurements which were taken in the workspaces on the fourth floor suggests variation in temperature whereas on the fifth floor, this variation is not so big.

These readings suggests that there was quite a lot of difference in terms of temperatures and relative humidity which can be due to improper functioning of the air conditioning and also due to the high internal heat gains in the workspaces which is why the temperatures are higher, especially in the centre of workspace, as more heat gains are concentrated there. The reason as to why the internal temperatures are higher can also be due to the fact that the floors has glazed facades (double glazing) and it traps the heat in keeping the space warmer (acting as a greenhouse).

4.4 b) Data loggers 2 data loggers were placed on the fifth floor. One of them was placed in the middle of the workspace where most of these is concentration of internal heat gains due to the equipment, loads as well as the occupants.

The second data logger was placed in 1 of the meeting room in order to understand the behaviour of the meeting room which is used occasionally for the meetings in the Figure 4.4.8.

2 1

Fig. 4.4.8 Location of Data Loggers 60

Improper AC functioning

Fig. 4.4.9 DataLoggers Measurements in Working Space (Data Logger 1)

4.4 b).i Working Space: The temperatures in the working space follows a pattern, from the graph, the cooling set point can be pointed out at 26°C as from that temperatures starts to decrease from there on. Air Conditioning was on during the measurements which can be seen in the temperature graph but the line is not straight which reflects improper functioning of the air conditioning as for proper functioning of air conditioning there should have been a straight line. As mentioned in the interview section, the occupants had previously also recorded that there is improper functioning of the air conditioning. From the data loggers readings, it can be seen, that there are traces of air conditioning which can be seen in the Fig 4.4.9, which shows improper functioning of the air conditioning.

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Fig. 4.4.10 DataLoggers Measurements in Meeting Room 4.4 b).ii Meeting Room: The temperatures in the meeting room are relatively high. The reasons behind the high temperatures can be owed to the following factors: Solar Radiation: The data logger was in the proximity of the window and the temperatures during the day were high between Tuesday to Friday (5-8th July).

Due to High Internal Heat Gains and smaller space High Outdoor Temperatures during the weekdays On Saturday, despite being sunny and high outdoor temperature the internal temperatures are not as high as the temperatures were between 5th-8th July, due to low internal heat gains. The temperatures on the Sunday are quite high, despite the low outdoor temperatures which can be due to direct sun light. High internal gains as there were some people going to the office over the weekend during that week as was mentioned by occupant.

Temperatures between Monday- Wednesday (11-13th July) were relatively lower which can be owed to Lower outdoor temperatures and raining. The internal temperature graph shows that it follows solar radiation, outdoor temperature and the internal heat gains. The solar radiation is important as the orientation of the meeting room is west facing so it allows more solar radiation to be transmitted deeply in the space.

Apart from it the main factors affecting the temperature in the spaces are the internal heat gains as well as the outdoor climatic conditions.

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CONCLUSIONS The main objective of the fieldwork was to identify the problems and what causes these problems in Offices in London in a real scenario.Through the observation, interviews and the measurements, the problems were clearly identified namely: a. Temperature Fluctuations which causes thermal discomfort b.

Glare which causes visual discomfort c.

Noisy environment which again causes disturbance to the occupants And their causes were also identified in the sections above.

Being a deep plan office suggested many problems but at the same time, it allows social amalgamation as in this set up of the office, it enables more social interaction amongst colleagues. Some well appreciated architectural elements by the occupants were identified such as terraced balconies, a space which they use occasionally.

The fieldwork was utilised for finding9 starting points for the analytical work in the next chapter. It helped in formulating the base case, with respect to the measurements of the space, the internal heat gains (occupants, equipment and lighting loads), materials that were used in the fieldwork office etc. As the problems were identified during the fieldwork, which were rectified by different parametric studies which are shown in detail in the next chapter.

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CHAPTER-5 ANALYTICAL WORK

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5.1URBAN STUDIES For understanding the solar radiation and daylight levels in the canyons surrounding the building, overshadow and solar radiation analysis were conducted using grasshopper.

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Fig. 5.1.1

21st March Solar Hour Access Source: Grasshopper

Fig. 5.1.2

21st March View from South East Source: Grasshopper

For the Solar Hour Access Analysis, with the help of sun vectors for a particular day, results showed that on March 21st : During the spring equinox, the canyons around are darker and southern faรงade receives more solar radiation then northern, eastern facades (Figure 5.1.1-5.2.2). It was found from the urban studies that there was no direct obstruction or overshadowing to the fifth floor, as the buildings around are lower in height.

On June 21st: The streets are slightly overshadowed but received good solar radiation especially the top floor of BDSP office. . (Fig 5.1.3-5.1.4)

Fig. 5.1.3

21st June Solar Hour Access Source: Grasshopper

21st June View from South East Source: Grasshopper

Fig. 5.1.5

Fig. 5.1.6

21st December Solar Hour Access Source: Grasshopper 68

Fig. 5.1.4

21st December View from South East Source: Grasshopper

On December 21st: The building is receiving the lowest amount of solar radiation. All the canyons around the site are completely overshadowed (Fig 5.1.5-5.1.6).

Top floor of BDSP office is not receiving enough Sunlight, which can be due to the fact the the solar radiation is very low in Winters.

Legend

Solar radiation studies shows, the amount of solar radiation received by the streets around the building and the buildingâ&#x20AC;&#x2122;s floor during Summers and Winter Months of the year. This analysis helps us to understand the amount of solar radiation that the streets and the 5th floor of the building, during summers and winters (Fig-5.1.7 and 5.1.10). These are considering 5th floor only as a part of it was constituted as the base case.

Fig 5.1.8 and 5.1.9 shows the amount of solar radiation received by different Facades during Summers and Winters respectively on the 5th (top) floor of the building.

Fig. 5.1.9

View showing Solar Radiation for March t0 Mid September

Fig. 5.1.9

View showing Solar Radiation for December to Feburary

Fig. 5.1.7

Solar Radiation for March- Mid September Source: Grasshopper

Fig. 5.1.10

Solar Radiation for December to Feburary

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5.2 DAYLIGHT ANALYSIS From the previous chapter (Fieldwork), through the observation, interviews and analysis from the measurements, problems in the form of thermal and visual discomfort were highlighted. This enabled the project to formulate the base case on the basis of these learnings from the fieldwork which were considered as the starting points for the analytical work. Part of the fifth floorâ&#x20AC;&#x2122;s workspace was taken as the base case as can be seen in the figure-5.2.1-5.2.2. It has an area of 222.5m2.

Figure-5.2.1 Main Area of in the Fifth Floor

Figure-5.2.2 Base Case Considered

The base case has three glazed facades (50%) which results in over illumination of the space as was specified by the occupants. As it was observed that the occupants in the workspace use artificial lighting which was due to improper distribution of light in the workspace, it helped in formulating simple objectives for daylight studies: to enhance more uniform distribution of daylight in the workspace and reduce the over illuminance (glare) from the space.

For this purpose, UDI (Useful Daylight Illuminance) between the range 100-2000 Lux for the occupied hours was considered as a valuable parameter as this is the range which lies in the proper daylight levels lies for an office space, along with this other factors such as Daylight Autonomy, and Daylight Availability which shows glare and over illumination were considered in improving the daylight.

Various Strategies such as use of Blinds, Light shelves, Overhangs, Vertical fins and their combinations with blinds were tested to attain optimum daylight levels in the workspace. These strategies were tested for different Window to Wall Ratios in order to understand these strategies impact and its adaptability on different facades. Besides the strategies for shading and uniformity of daylight, a different layout where all the four facades were exposed and the experimentation with its window to wall ratios were also tested. These are discussed in the subsections that follows.

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5.2 DAYLIGHT STUDIES: 5.2.1 a) Basecase: 50% Glazed Daylit Area (DA350lux [50%]) : 100% of floor area Mean Daylight Factor: 8.5% Occupancy: 1827 hours per year

Fig 5.2.3 View of the Basecase

(Scale for Daylight Autonomy)

Fig 5.2.4 Daylight Autonomy for 350 Lux

Materials: Walls: 70% Reflectivity Ceiling: Floor: 20% Reflectivity Glass: Clear Glass Low E- 65% Reflectivity This section discusses the different strategies that were used in evaluating different strategies for uniform distribution of daylight as well as shading the facades for the base case (Figure 5.2.3).

The process started with testing which strategy is the best in providing optimum daylight levels in the workspace by testing blinds, overhangs and light shelves for the base case, when that was achieved, what strategy works the best for particular facade (including the west façade) were tested. These strategies were tested for different window to wall radios, and which window to wall ratio works the best for daylight was also established and eventually a layout was proposed.

The first test was done on the base case in order to understand its performance.There was a big portion of the workspace which is over lit and has a glare problem (which was also highlighted during the occupantsâ&#x20AC;&#x2122; interview during the fieldwork).

Mean Daylight Autonomy is 94.56% of the time occupied for 350 Lux (Fig.5.2.4).

Fig 5.2.5 UDI:100-2000 Lux

Fig 5.2.6 UDI:2000 Lux and above

For analysing the daylight, it is also important to find out how much daylight is within the limit of range of optimum daylight levels, for this purpose, Useful Daylight Illuminance (UDI) was calculated and the range between 100-2000 Lux was considered as this is the range which is useful for optimum daylight levels for the workspace (Fig.5.2.6).

From the analysis, UDI for 100-2000 Lux Mean Useful Daylight Illuminance is 60.19% of the time occupied.

At the same time, from UDI for 2000 lux (Fig. 5.2.6) or more having Mean Useful Daylight Illuminance was 39.08% of the time occupied and from the Daylight Availability, the Mean Daylight Availability was 38.56% of the time occupied, from the figure, it is clear that there is a big problem with the glare which was causing visual discomfort (Fig.5.2.7).

Overlit Area: Potential for Glare

Fig 5.2.7 Daylight Availability 72

(Scale for the figures above) *Sources of Figures: Diva

5.2.1 b) Light Shelves Daylit Area (DA350lux[50%]) : 100% of floor area Mean Daylight Factor: 7.1% Occupancy: 1827 hours per year Materials: Walls: 70% Reflectivity Ceiling: Floor: 20% Reflectivity Glass: Clear Glass Low E- 65% Reflectivity Lightshelf: Sheet Metal As there are many kinds of light shelves, the aim of using light shelves is to distribute the daylight in a building which can be beneficial for a deep plan spaces. Horizontal Light shelves at a height of 2.25 meters from the ground and having a depth of 1.2 meters (Fig 5.2.8).

These external light shelves were seen as more effective for distributing the light deeper in workspace space as well as in reducing glare in comparison to other light shelves.

Fig 5.2.8 View of the Basecase

Fig 5.2.9 Daylight Autonomy for 350 Lux

(Scale for Daylight Autonomy)

The Mean Daylight Autonomy was found to be 93.61% of the time occupied for 350 Lux (Fig. 5.2.9).

The (UDI) ranged between 100-2000 Lux had Mean Useful Daylight Illuminance of 65.47% of the time occupied which is slightly better than the base case, this is the range for the optimum daylight levels in the workspace. The Useful Daylight Illuminance for levels for 2000 lux and above, had Mean Useful Daylight Illuminance of 33.62% of the time occupied. With the analysis of the Daylight Availability, the Mean Daylight Availability was found to be 41.18% of the time occupied which is slightly more (3%) then base case. (Fig.5.2.10-5.2.12) This case is slightly better in its performance then the base case, in terms of having Useful Daylight Levels in the range 100-2000 Lux. But this case still is not very successful in reducing the Over Illuminance and Glare substantially. So, other strategies such as use of overhang was tested which is discussed in the next subsection.

Fig 5.2.10 UDI: 100-2000 Lux

Fig 5.2.11 UDI: 2000 Lux and above

Overlit Area: Potential for Glare

(Scale for the figures above) *Sources of Figures: Diva

Fig 5.2.12 Daylight Availability

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5.2.1 c) Overhang Daylit Area (DA350lux[50%]) : 100% of floor area Mean Daylight Factor: 6.9% Occupancy: 1827 hours per year

Fig 5.2.13 View of the Basecase

Fig 5.2.14 Daylight Autonomy for 350

Materials: Walls: 70% Reflectivity Ceiling: Floor: 20% Reflectivity Glass: Clear Glass Low E- 65% Reflectivity Overhang: Sheet Metal To analyse the impact of overhang, two kinds of overhangs were considered: a) 0.5m wide and b) 1m wide. The one discussed here is 1m wide (Fig 5.2.13), as this one performed better than the 0.5m wide overhang. The 0.5m overhang study can be seen in the appendix.

The Mean Daylight Autonomy was found to be 91.46% of the time occupied for 350 Lux (Fig. 5.2.14)

(Scale for Daylight Autonomy)

The UDI ranged between 100-2000 Lux had Mean Useful Daylight Illuminance of 72.32% of the time occupied which is a much better result (Fig 5.2.15), in comparison with the base case.

The UDI ranged 2000 lux and above, had Mean Useful Daylight Illuminance of 26.49% of the time occupied with the analysis of the Daylight Availability, the Mean Daylight Availability was found to be 48.77% of the time occupied which is (10%) better than base case.

Fig 5.2.15 UDI: 100-2000 Lux

This case is much better in its performance then the base case, in terms of having better Daylight Levels in the range 100-2000 Lux. This case again not very successful in reducing considerable amount of Over Illuminance and Glare. In order to improve it further some other strategies such as Blinds were tested whose performance is discussed in the next subsection.

Fig 5.2.16 UDI:2000 Lux and above

Overlit Area: Potential for Glare

Fig 5.2.17 Daylight Availability 74

(Scale for the figures above) *Sources of Figures: Diva

5.2.1 d) Blinds Daylit Area (DA350lux[50%]) : 61% of floor area Mean Daylight Factor: 8.5% Occupancy: 1827 hours per year Blinds Open: 20% of occupied hours Materials: Walls: 70% Reflectivity Ceiling: Floor: 20% Reflectivity Glass: Clear Glass Low E- 65% Reflectivity

Fig 5.2.18 View showing the Blinds

The blinds considered for the project allows 25% of the diffused daylight in the space.These blinds are considered for a case when they all are down or up together respectively.(fig. 5.2.18) The Mean Daylight Autonomy was found to be 58.79% of the time occupied for 350 Lux (fig 5.2.19).

The UDI ranged between 100-2000 Lux had Mean Useful Daylight Illuminance of 91.03% for occupied which is a major improvement. The Useful Daylight Illuminance for levels for 2000 lux and above, had Mean Useful Daylight Illuminance of 5.51% of the time occupied. With the analysis of the Daylight Availability, the Mean Daylight Availability was found to be 48.8% of the time occupied which is 10% more than base case (Fig-5.2.20-5.2.21).

Fig 5.2.19 Daylight Autonomy for 350

The case with the blinds, performs quite better than the base case, as in this case, over illumination has reduced massively in comparison to the base case.

In order to investigate if these results can further be improved, tests with combination of light shelves with blinds, overhangs and blinds were tested.

Fig 5.2.20 UDI:100-2000 Lux

Fig 5.2.21 UDI:2000 Lux and

Overlit Area: Potential for Glare

(Scale for the figures above) *Sources of Figures: Diva

Fig 5.2.22 Daylight Availability 75

AA 2015-16 MSC. SUSTAINABLE DESIGN ARCHITECTURE 5.2.1 e) Lightshelves with Blinds Daylit Area (DA350lux[50%]) : 43% of floor area Mean Daylight Factor: 6.9% Occupancy: 1827 hours per year Blinds Open: 21% of Occupied Hours Fig 5.2.23 Overhangs and Blinds

Materials: Walls: 70% Reflectivity Ceiling: Floor: 20% Reflectivity Glass: Clear Glass Low E- 65% Reflectivity Overhang: Sheet Metal For this case, combination of light shelves and blinds was tested. (fig 5.2.23)

Fig 5.2.24 Daylight Autonomy for 350

(Scale for Daylight Autonomy)

The Mean Daylight Autonomy was found to be 45.97% of the time occupied for 350 Lux which is slightly low (Fig.5.2.24).

The UDI ranged between 100-2000 Lux had Mean Useful Daylight Illuminance of 91.07% for occupied time which is similar in performance as in the case of blinds. The UDI ranged 2000 lux and above, had Mean Useful Daylight Illuminance of 2.81% of the time occupied. With the analysis of the Daylight Availability, the Mean Daylight Availability was found to be 48.96% for occupied time (fig 5.2.25-5.2.26).

This case is much better in its performance then the base case, in terms of having better Daylight Levels in the range 100-2000 Lux. Its performance is quite similar to the case of blinds but itâ&#x20AC;&#x2122;s better in reducing over illumination and glare.

Fig 5.2.25 UDI: 100-2000 Lux

Its advantage over only blinds case is when the occupants keep the blinds up, even then the UDI for 100-2000 lux level are quite better than the base case, and it increases visual comfort as the occupants can enjoy the outside view by keeping the blinds up as the UDI ranged 100-2000 lux is 12% more than the base case and blinds can be applied when thereâ&#x20AC;&#x2122;s too much glare.

Fig 5.2.26 UDI:2000 Lux and

Overlit Area: Potential for Glare

Fig 5.2.27 Daylight Availability 76

(Scale for the figures above) *Sources of Figures: Diva

5.2.1 f) Overhangs with Blinds Daylit Area (DA350lux[50%]) : 56% of floor area Mean Daylight Factor: 7.1% Occupancy: 1827 hours per year Blinds Open: 21% of Occupied hours Materials: Walls: 70% Reflectivity Ceiling: Floor: 20% Reflectivity Glass: Clear Glass Low E- 65% Reflectivity Light shelve: Sheet Metal

Fig 5.2.27 View showing the Blinds

For comparability, combination of overhangs and blinds was tested which is discussed below (fig. 5.2.27) The mean daylight autonomy was found to be 53.84% of the time occupied for 350 Lux which is better than combination of overhangs and blinds case (Fig.5.2.28).

The UDI ranged between 100-2000 Lux had Mean Useful Daylight Illuminance of 92.22% of the time occupied which is better in performance as in the case of blinds and best in comparison to all the other cases. The UDI ranged 2000 lux and above, had Mean Useful Daylight Illuminance of 5.51% of the time occupied which is same as in the case of blinds. With the analysis of the Daylight Availability, the Mean Daylight Availability was found to be 52% of the time occupied. (Fig 5.2.29-5.2.30).

This case is much better in its performance then the base case, in terms of having better Daylight Levels in the range 100-2000 Lux. Its performance is quite similar to the case of blinds but its better in reducing over illumination and glare.

Fig 5.2.28 Daylight Autonomy for 350

(Scale for Daylight Autonomy)

Fig 5.2.29 UDI:100-2000 Lux

The light shelves with blinds and overhangs with blinds have similar performances, with overhangs with blinds case is better in reducing glare more than the light shelves with blinds case as well as in case of UDI: 100-2000 Lux.

Fig 5.2.30 UDI:2000 Lux and

Overlit Area: Potential for Glare

(Scale for the figures above) *Sources of Figures: Diva

Fig 5.2.31 Daylight Availability

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AA 2015-16 MSC. SUSTAINABLE DESIGN ARCHITECTURE 5.2.2 a) Comparasion Among Different Strategies for Base Case

Basecase: 50% Glazed

Light Shelves: 1.2 wide (Ext)

Overhangs: 1 wide

Daylit Area (DA350lux[50%]) : 100% of floor area Mean Daylight Factor: 8.5% Occupancy: 1827 hours per year

Daylit Area (DA350lux[50%]) : 100% of floor area Mean Daylight Factor: 7.1% Occupancy: 1827 hours per year

Daylit Area (DA350lux[50%]) : 100% of floor area Mean Daylight Factor: 6.9% Occupancy: 1827 hours per year

DayLight Autonomy % Occupied Hours

94.56%

93.61%

91.07%

65.47%

72.32%

33.62%

26.49%

41.18%

48.77%

UDI: 100-2000 Lux (% Occupied Hours)

60.19%

UDI: 2000 Lux and above (% Occupied Hours)

39.08%

Daylight Availibility (% Occupied Hours)

56%

The basecase has quite high amount of glare and over illuminance. UDI in the range 100-2000 Lux is not very high (as this is the range needed for workspaces).

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This case has slightly better UDI in the range 100-2000 Lux then the basecase, but the overillumination and glare is still high.

This case has much better UDI in the range 100-2000 Lux then the basecase, but the overillumination and glare is quite high.

Source:Diva

Blinds

Light shelves and Blinds

Overhangs and Blinds

Daylit Area (DA350lux[50%]) : 61% of floor area Mean Daylight Factor: 8.5% Blinds Open: 20% of Occupied Hours

Daylit Area (DA350lux[50%]) : 43% of floor area Mean Daylight Factor: 6.9% Blinds Open: 21% of Occupied Hours

Daylit Area (DA350lux[50%]) : 56% of floor area Mean Daylight Factor: 7.1% Blinds Open: 21% of Occupied Hours

58.79%

45.97%

53.84%

91.03%

91.07%

92.22%

5.51%

2.81%

5.51%

48.80%

42.96%

52%

This case works quite well, as the UDI for the range100-2000 Lux is quite high and has reduced glare and overillumination substaintially.

This case works quite well, as the UDI for the range100-2000 Lux is quite high and has reduced glare and overillumination substaintially (better then only blinds),it has slightly low daylit area.

This case works the best, as reduces substantial overillumination and glare, at the same time, UDI is quite high for the range 100-2000 Lux.

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5.2.2 b) Comparasion Among Different Strategies for reduced window to wall

After attaining optimum daylight levels and reducing the glare in the base case with the use of strategies, a similar analysis was done for a case, where the window to wall ratio was reduced to 30% on all the 3 sides, to evaluate the effect of these strategies performs on reduced window to wall ratio case. It would also help in understanding the adaptability of these strategies in this case. In a similar manner, a performance matrix was made which helps in evaluating the performances of different cases. The results suggests that overhangs with blinds performs the best in this case as well followed by light shelves with blinds and just the case with the blinds.

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Window to Wall 30% Glazed

Light Shelves: 1.2 wide (Ext)

Overhangs: 1 wide

Daylit Area (DA350lux[50%]) : 100% of floor area Mean Daylight Factor: 8.5% Occupancy: 1827 hours per year

Daylit Area (DA350lux[50%]) : 100% of floor area Mean Daylight Factor: 6.5% Occupancy: 1827 hours per year

Daylit Area (DA350lux[50%]) : 61% of floor area Mean Daylight Factor: 8.6% Occupancy: 1827 hours per year

DayLight Autonomy % Occupied Hours 93.21%

92.83%

93.61%

68.54%

69.38%

30.43%

29.74%

50.54%

50.25%

UDI: 100-2000 Lux (% Occupied Hours) 63.19%

UDI: 2000 Lux and above (% Occupied Hours) 35.88%

Daylight Availibility (% Occupied Hours)

39.89%

The basecase has quite high amount of glare and over illuminance. UDI in the range 100-2000 Lux is not very high (as this is the range needed for workspaces).

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This case has slightly better UDI in the range 100-2000 Lux then the basecase, but the overillumination and glare are still quite high.

The performance of overhang is quite similar, with slight differences, to light shelve in terms of UDI and the over illuminance.

Blinds

Light Shelves and Blinds

Overhangs and Blinds

Daylit Area (DA350lux[50%]) : 61% of floor area Mean Daylight Factor: 8.6% Occupancy: 1827 hours per year Blinds Open: 21% of Occupied hours

Daylit Area (DA350lux[50%]) : 53% of floor area Mean Daylight Factor: 6.5% Occupancy: 1827 hours per year Blinds Open: 21% of Occupied hours

Daylit Area (DA350lux[50%]) : 51.74% of floor area Mean Daylight Factor: 7.4% Occupancy: 1827 hours per year Blinds Open: 19% of Occupied hours

63.19%

51.7%

51.43%

90.6%

91.54%

93%

6.29%

2.65%

2.7%

49.45%

47.51%

49.48%

This case works quite well, as the UDI for the range100-2000 Lux is quite high and has reduced glare and overillumination substaintially.

This case works quite well, as the UDI for the range100-2000 Lux is quite high and has reduced glare and overillumination substaintially (better then only blinds),but the daylight availability is lower then blinds.

This case works the best, as it reduces overillumination and glare, substantially at the same time, UDI is quite high for the range 100-2000 Lux. The daylight availability is higher then blinds.

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5.2.2 Shading devices for different Orientations: In order to understand, which type of shading device works the best for different facades? A test for shading devices was done. These tests involved the case that evaluates which shading strategy works best for the west (if it was also glazed).

NORTH Starting with north, it is considered a very good orientation in London Climate as it allows only diffused light into a space (no direct), which anyways reduces the risk of glare. For evaluating good shading strategy for the north orientation, two tests were done: one with an overhang and one without an overhang .

From the daylight autonomy and UDI100-2000 it can be seen that the overhang is much effective in evenly distributing the light deeper into the workspace in comparison to the case where thereâ&#x20AC;&#x2122;s no overhang.

WITHOUT OVERHANG

WITH OVERHANG

FIG.5.2.32 DAYLIGHT AUTONOMY

WITH OVERHANG: Daylight Autonomy 36.02% 100-2000 Lux: 83.58% Daylight Availability: 36.02% 2000+ Lux: 1.85% WITHOUT OVERHANG: Daylight Autonomy 26.9% 100-2000 Lux: 53.97% Daylight Availability: 81.71% 2000+ Lux: 3.31%

FIG. 5.2.33 100-2000 LUX

(Scale for Daylight Autonomy) Overlit Area: Potential for Glare

FIG.5.2.34 DAYLIGHT AVAILABILITY

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(Scale for the figures above) *Sources of Figures: Diva

SOUTH South is a major contributor of direct sunlight in the space, bringing in high level of glare, in order to reduce that, 2 tests were considered, 1) one with an overhang 2) horizontal shading devices placed at every 1 meter height. The evaluation of results suggests that horizontal shading devices performs better as it distributes better daylight in the space and it performs better in terms of reducing glare and providing better daylight light in the space (Figure 5.2.35-5.2.37 ) then simply providing an overhang.

WITH OVERHANG

WITH HORIZONTAL SHADING DEVICES

FIG.5.2.35 DAYLIGHT AUTONOMY

WITH OVERHANG: Daylight Autonomy 59.21% 100-2000 Lux: 81.71% Daylight Availability: 33.46% 2000+ Lux: 12.78% WITH HORIZONTAL SHADING DEVICES: Daylight Autonomy 54.77% 100-2000 Lux: 84.08% Daylight Availability: 40.2% 2000+ Lux: 8.81%

FIG. 5.2.36 100-2000 LUX

(Scale for Daylight Autonomy) Overlit Area: Potential for Glare

FIG.5.2.37 DAYLIGHT AVAILABILITY

(Scale for the figures above) *Sources of Figures: Diva

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East For east faรงade, usually vertical fins works fine so the two tests were considered for the east faรงade 1) vertical fins 2) overhang. The performance of both the shading elements was quite similar. For UDI for 1002000 Lux, vertical fins performed better than overhangs, whereas, overhang performed better in reducing over illumination, glare, and providing better daylight levels in the space (Figure 5.2.38-figure 5.2.40).

Therefore, overhang was considered a better choice for the east faรงade for the base case considered for the project.

WITH OVERHANG

WITH VERTICAL SHADING DEVICE

WITH OVERHANG: Daylight Autonomy 35.82% 100-2000 Lux: 68.25% Daylight Availability: 23.01% 2000+ Lux: 6.17% FIG.5.2.38 DAYLIGHT AUTONOMY WITH VERTICAL SHADING: Daylight Autonomy 35.8% 100-2000 Lux: 72.75% Daylight Availability: 20.04% 2000+ Lux: 7.81%

FIG. 5.2.39 100-2000 LUX

(Scale for Daylight Autonomy) Overlit Area: Potential for Glare

FIG.5.2.40 DAYLIGHT AVAILABILITY

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(Scale for the figures above) *Sources of Figures: Diva

WEST A case, where the west is also exposed to the sun was also considered, in order to evaluate strategy for shading 2 cases were considered 1) vertical fins 2) overhang. From the evaluation of result based on the UDI (100-2000 lux), daylight availability as well as daylight autonomy, vertical fins works better than an overhang as can be seen in (Figure,5.2.41-5.2.42 ). The case of vertical fins receives slightly more glare, but since it performs quite better in other parameters, therefore, vertical fins were considered a better choice for the west faรงade.

WITH OVERHANG

WITH VERTICAL SHADING DEVICE

WITH OVERHANG: Daylight Autonomy 34.57% 100-2000 Lux: 63.66% Daylight Availability: 22.65% 2000+ Lux: 6.44% FIG.5.2.41 DAYLIGHT AUTONOMY WITH VERTICAL SHADING: Daylight Autonomy 52.42% 100-2000 Lux: 85.19% Daylight Availability: 35.93% 2000+ Lux: 9.42%

FIG. 5.2.42 100-2000 LUX

Overlit Area: Potential for Glare

FIG.5.2.43 DAYLIGHT AVAILABILITY

(Scale for the figures above) *Sources of Figures: Diva

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Establishing the best possible window to wall ratio: In order to establish which case works the best for window to wall ratio for all the 3 facades: extracted from the base case and for 4 glazed facades case.

In order to decide the window to wall ratios for 3 glazed facades (Base case), the process started with testing 4 different cases: 2 cases of similar window to wall ratios (30:30 and 20:20 on both north and south facades). Another 2 cases were considered for the analysis with having different window to wall ratios (30:20 and 20:30 on north and south facades respectively). The analysis suggested that the case with 30 percentage of window to wall radios on both the facades performed the best in terms of daylight parameters: Daylight Availability, Lower Glare and UDI in the range 100-2000 Lux (Figure 5.2.44-5.2.48). While analysing these 4 cases, it became clear that keeping the window to wall ratio on both the facades has a better daylight performance rather than keep them different. Also through the tests it also became clear that south is a major contributor of sunlight in the space so the cases where the south façade had 20% of glazing didn’t perform as well as it did when 30% glazing was used although glare was more from the south for which horizontal plates can help (as seen in previous sections), as for north there was not a major performance difference in 20% or 30%, but it still performed better when we used 30% glazing in the north façade.

Daylight Autonomy 79.19% 100-2000 Lux: 77.15% Daylight Availability: 57.02% 2000+ Lux: 19%

FIG. 5.2.44 DAYLIGHT AUTONOMY

FIG. 5.2.48 100-2000 LUX

Overlit Area: Potential for Glare

(Scale for the figures above) *Sources of Figures: Diva

FIG.5.2.45 100-2000LUX

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FIG.5.2.49 DAYLIGHT AVAILABILITY

After getting window to wall ratios for North and South Facades, tests were done to check which case works the best for east so two tests were done 1) 30% and 2) 20% window to wall ratio on the east keeping the north and south as 30% respectively. Through the tests it was clear that the case where east had a window to wall ratio of 20% performed better than the 30% in terms of UDI (100-2000 Lux), daylight availability as well as in terms of over illuminance and glare. (Figure,). The results were better for 20% window to wall ratio when the tests were taken with the overhangs (and horizontal shading) and without them. The results shown here are with the overhangs. The results for the case of window to wall ratio of 30% can be viewed in appendix.

Once window to wall ratios were found for the 3 orientations, similar process was followed as in case of east orientation, tests were done to check which case works the best for all four facades so two tests were done 1) 30% and 2) 20% window to wall ratio on the west keeping the north, south and east as 30%, 30% and 20% respectively. Through the tests, a similar performance was observed but the case where west had a window to wall ratio of 20% performed slightly better than the 30% in terms of UDI (100-2000 Lux), daylight availability as well as in terms of over illuminance and glare. (Figure 5.2.50-5.2.52,). The results were better for 20% window to wall ratio when the tests were taken with the shading devices on each faรงade and without them. The results shown here are with the shading devices. The results for the case of window to wall ratio of 30% can be viewed in appendix.

Daylight Autonomy 91.14% 100-2000 Lux: 83.49% Daylight Availability: 63.29% 2000+ Lux: 15.36%

FIG. 5.2.50 DAYLIGHT AUTONOMY

FIG. 5.2.51 100-2000 LUX

Overlit Area: Potential for Glare

(Scale for the figures above) *Sources of Figures: Diva

FIG.5.2.52 100-2000LUX

FIG.5.2.53 DAYLIGHT AVAILABILITY

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AA 2015-16 MSC. SUSTAINABLE DESIGN ARCHITECTURE Layout Solutions: The base case where orientations North, South and East glazed and west assumed having a wall, when considered in terms of layouts was considered as west was where the services such as core (lifts, toilets) would be. After optimising the daylight levels in the base case through different strategies, another layout was thought upon, in this case all the facades were considered as glazed, where the centre most part can be used for the core purpose, as due to the deep plan the centre part can remain slightly darker in the centre (Figure 5.2.54), although this case has a major issue with glare and uneven distribution daylight in the workspace, which when treated with shading devices has these issues resolved effectively. Also, according to the passive zone principle, depth until 6 meters, is considered good for daylight performance of a space, so the space until 6 meters from all the facades can be used for workspaces and the centre part remaining can be used for services or circulation space or a meeting point for the office goers (interactive zone) (Figure 5.2.55), which can make the layout more interactive amongst the office goers at the same time it can make the space more open rather than deep plan. It would enable a better visual comfort for the office goers.

Darker Patch

FIG.5.2.54 Daylight Autonomy

Type A

Type B Fig. 5.2.55 Possible Layouts

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CONCLUSIONS FROM DAYLIGHT ANALYSIS In this base case which was taken from the real case scenario, there were two main problems: 1) Glare and Over illumination 2) improper daylight levels in the space. To overcome these problems, many tests were done based on different strategies. The main parameters while deciding which strategies works the best were UDI (ranged 100-2000 Lux), Daylight Autonomy and Daylight Availability.

It was observed that the blinds played a good role in reducing the glare and over illumination and improving the UDI ranged between 100-2000 Lux. But this performance was further enhanced when the blinds were combined with shading devices. It was found that they have similar performances, with overhangs with blinds performed the best when located on the east as well as northern with horizontal shading devices on the southern and vertical fins on the western facades.

Using shading devices with blinds have an added advantage that itâ&#x20AC;&#x2122;s a more adaptive method then just using blinds as it gives better visual comfort in terms of view and better UDI (100-2000 lux) and when there is possibility of glare, blinds can be put down. Best possible window to wall ratios were established in terms of having better daylight levels: 30-30-2020 (%) for south, north, east and west respectively.

A suggestion for a better layout is also proposed which helps in making the space more interactive as well is better in terms of daylight performance: all the 4 glazed facades with the central portion being used as a core, interactive zone etc.

This helps in reducing the dependence of artificial lighting during the daytime effectively.

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CONCLUSIONS

In this base case which was taken from the real case scenario, there were two main problems: 1) Glare and Over illumination 2) improper daylight levels in the space. To overcome these problems, many tests were done based on different strategies. The main parameters while deciding which strategies works the best, UDI, Daylight Autonomy and Daylight Availability were considered crucial as these factors helps in evaluating the two problems mentioned above.

It was observed that the blinds played a good role in reducing the glare and over illumination and improving the UDI ranged between 100-2000 Lux. But this performance was further enhanced when the blinds were combined with the overhangs and light shelves. It was found that they have similar performances, with overhangs with blinds better in terms of UDI ranged between 100-2000 lux and for daylight availability for reduced window to wall area (30%) and in reducing glare and over illumination in the fully glazed base case but having the limitation that it has slightly lower day lit area and lower daylight autonomy in case of base case (70%) where using light shelves with blinds have better day lit area and daylight autonomy.

Using light shelf or overhang with blinds have an added advantage that itâ&#x20AC;&#x2122;s a more adaptive method then just using blinds as it gives better visual comfort in terms of view and better UDI then the base case (for 100-2000 lux) and when there is possibility of glare, blinds can be put down. Considering the adaptive nature for overhangs with blinds and light shelves with blinds, using overhangs with blinds is a better option as even without the blinds the UDI ranged between 100-2000 lux is better for both the cases (base case and 30% window to wall ratio).

Usage of these strategies can reduce the dependence on artificial lighting during the day time, as optimum daylight levels are met uniformly during the day.

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5.3 THERMAL ANALYSIS

The results from the daylight analysis were used as the starting points for the thermal analysis for the project. Through the evaluation of the daylight studies, it became easier to decide which window to wall ratios to analyse the thermal analysis as well as the shading devices for each faรงade had been decided from the daylight studies which would be tested in the thermal model. The objective of the thermal analysis is to reduce the Heating and Cooling Demands which would result in lower Energy Consumption of the current workspace as well as providing comfortable indoor working environment to the office goers. In order to achieve the objectives mentioned, some strategies were implemented which are discussed in the following sections:

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5.3.1 Base Case

Fig 5.3.1 Base Case

The inputs used for the analysis such as the U values, occupancy are mentioned below: Occupancy: 8 m2/ workstation Occupancy Hours: 10:00-17:30 on the weekdays Infiltration: 0.5 ac/h Equipment: 13.8 W/m2 Artificial Light: 9.3 W/m2 (as per observation during fieldwork)

Steel Framing 100mm Lightweight Concrete 60mm Wall Insulation Gypsum Board Paint

U- Value 0.42 W/m2-k

Fig 5.3.2 Wall Material Glass 4mm Airspace10mm

Glass 4mm

U- Value 2.5 W/m2-k SHGC 0.35

Fig 5.3.3 Window Material

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The process started with the base case, which was considered the same 50% glazed on 3 sides namely: South, East and the North as in case of daylight analysis (Fig.5.3.1). As the workspace (from the fieldwork), is controlled by air conditioning and heating

by Natural Gas, for understanding and evaluating its performance in absence of Heating and Cooling sources was tested, keeping into consideration the various factors which were evaluated on the basis of the fieldwork as well as the time of the building’s regulations- early 1990’s.

The U value of the materials and the selection of the materials was considered on the basis of the building regulations of the early 1990’s (Killip, 2005) (The U values referred from this document).

The wall and window detail can be viewed Fig.5.3.25.3.3. Also it was observed during the fieldwork that the office workspace has a low thermal mass which is based on the fact the gypsum boards have been used in the walls and the ceilings and carpets on the floor.

The overall year performance of the base case suggested that, the temperatures does not fall into the comfort band, with the temperatures below the comfort band by at least 2-3K during the winters, and overheating was found during the summer with temperatures rising up to 35°C as can be seen in (appendix).

High overheating can be accounted from the overheating hours in between the Months: April to November, in which the main overheating is observed during the summers as can be seen from the (Figure 5.3.5), despite considering the windows open during the summer months.

As the temperatures for most part of the year, are not in the comfort band, considerably high heating and Cooling Loads were observed (Fig 5.3.6).

Heating Loads (KWH/m2)

Cooling Loads (KWH/m2)

Fig 5.3.6 Heating and Cooling Loads

In order to improve the thermal performance of the workspace, some strategies were implemented which are discussed in following sections.

Fig 5.3.5 Base Case Overheating Hours 97

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5.3.2 Strategies for improved Case: better façade, shading with blinds,Vent (Nat and Night), and Inputs People, lighting, equipment, infiltration

Fig 5.3.6 High Thermal Mass in the Envelope The changed inputs are mentioned below: Infiltration: 0.2 ac/h Artificial Light: 8 W/m2

In order to improve the performance of the base case, the first step was by improving the building envelope which was done by improving the U value of the materials, such as using High Thermal Mass Construction for the walls (Figure 5.3.6) and better glass configuration (Figure5.3.7).

For the purpose of analysis, a typical summer week was considered: 17June-23 June (Figure 5.3.9) which is on the next page. By improving the building envelope (High Thermal Mass Construction and good quality glass: by having low SHGC value of the glass helps in reducing the solar heat gain more), reduction in the temperatures was observed during the typical summer week by 2-3K especially during the occupied days and hours although some temperatures rising above 30°C can be observed. Opening of the windows during the occupied hours was considered during the tests. During the weekends, the temperatures are relatively lower and no major variation in the temperature can be seen which can be owned to low internal heat gains.

The overheating during the summer has also reduced to half which can be viewed in the appendix.

Fig 5.3.7 Improved Wall Material: High Thermal Mass

Fig 5.3.8 Improved Window Configuration

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Fig 5.3.9 Typical Summer Week

Fig 5.3.10 Added Shading Devices

In order to further improve the performance, Shading devices along with internal blinds were added (in accordance with the daylight analysis results), it can be seen from the figure that, adding them has reduced the temperatures further, with most of the temperatures falling in the comfort band with a reduction of 1-2K. The strategy works very well for reducing the overheating during the summers (figure 5.3.9).

As it is established that High Thermal Mass and better quality glass as well as Shading Devices works well with Night Ventilation, Thermal Mass with Shading Devices were tested with Night Ventilation, (in addition to Natural Ventilation through the opening of the windows during the occupied hours). It can be seen that the temperature has further dropped (0.5-2K) and the temperature lies in the comfort band during the occupied hours, with the temperature falling below the comfort band at night by 1-2K. Despite the outdoor temperature being quite low, due to the use of High Thermal Mass Construction the temperature doesnâ&#x20AC;&#x2122;t drop too low. Effect of Night Ventilation on Overheating is tremendous (Figure 5.3.12) which can be seen on the next page.

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Fig 5.3.12 Effect of Night Ventilation on Overheating Hours

In order to evaluate the performance of these strategies during the winters, a typical winter week was considered for the study (2 Jan- 8 Jan).

In comparing the temperatures for a case of better envelope with the base case, huge rise in temperature was observed (6-8K). By improving the envelope (Using better materials and reducing the infiltration: keeping the building air tight) helps in storing the heat better during the winters. At the same time internal heat gains played an important role in increasing them further. The temperatures lies in the comfort range during the occupied hours, with temperatures falling below it during the night by 1-2K due to low temperatures outside as well as during the weekends due to low internal heat gains as can be seen in the Figure 5.3.13 which can be seen on the next page.

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Fig 5.3.13 Typical Winter Week When the shading devices with the blinds were incorporated, a further rise of 0.5-1K in temperature was observed mainly during the night. Keeping the blinds down during the night helped a little bit further in storing the heat inside the workspace during the night.

By incorporating these strategies, thereâ&#x20AC;&#x2122;s a high drop in Heating Loads and Cooling Loads was observed Figure 5.3.14. The performance of the whole year can be seen in the appendix. These strategies were successful in providing comfort for the most part of the year to its occupants, at the same time helped in reducing the Loads.

Fig 5.3.14 Comparison of Loads for the Improved Case

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AA 2015-16 MSC. SUSTAINABLE DESIGN ARCHITECTURE 5.3 Future scenario: With the use of these strategies, in the case if we keep the same inputs as in the improved case then the heating loads are further reduced but thereâ&#x20AC;&#x2122;s some increase in Cooling loads (Figure 5.3.15). The overheating hours with the introduction of Night Ventilation will reduce it further (Figure 5.3.16).

When another future case is considered where the Internal Heat Gains are reduced, that is Equipment: 10 W/m2 Artificial Light: 3 W/m2 As in the future, it can be assumed a scenario where energy efficient equipment might be used, will affect the overheating tremendously as in that case overheating is almost eliminated, (Figure 5.3.15) but in that case, heating loads remains the same as the current improved case but reduction in cooling loads is observed (Figure 5.3.17). It can be said that internal heat gains affect the Overheating and Loads substantially.

Fig 5.3.15 Comparison of Loads for Future Scenarios and Current Improved Case

Fig 5.3.17 Overheating if the Loads are reduced

Legend indicating the months which has overheating

Fig 5.3.16 Overheating Hours if the loads remain the same 102

5.4 Window to wall reductions In order to find out the thermal performance of the case for the reduced window to wall ratio, the case which was performing the best in terms of daylight was considered for the analysis that is 20% , 30%, 30% on East, North and South respectively.

Fig 5.3.18 Summer Week Performance Summer Week As it can be seen in the Figure 5.3.18 that with the use of High Thermal Mass, the temperatures are falling in the comfort band most of the time except on Sunday- Tuesday , although the internal heat gains are low on Sunday, the reason for high internal temperatures are due to high outdoor temperature.

Applying shading follows a similar pattern but there is a reduction in temperature of around 0.5K with the shading throughout the week. Applying Night Ventilation helped in causing a uniformity in the temperature during the week with less fluctuations in the temperature and the temperatures are falling in the comfort band except on Tuesday when the temperature is higher by 1K which is due to high outdoor temperatures.

Fabric: High Thermal mass

Addition of Shading Devices

Night Ventilation

Fig 5.3.19 Strategies for each Step for Improvement in Thermal Performance

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Fig 5.3.20 Overheating for reduced window to wall ratios

In comparison with the Case with only had Thermal Mass for reduced Window to wall Ratios , then the Shading Devices, Night Ventilation has helped in reducing overheating substancially.

Night Ventilation helped in reducing overheating

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In terms of Overheating with Night Ventilation, the number of overheating hours are lower than the Improved Case (Figure 5.3.20). (that is from 1.9% of the occupied hours to 1.8%).

Fig 5.3.21 Winter Week Performance Winter Week During the winter week Figure 5.3.21, when only thermal mass is used, mostly the temperatures are slightly below the comfort band, but when shading devices are added, with blinds down during the night as they help in keeping the heat intact and reduces the amount of infiltration further, thus helping in improving the temperatures substantially. The temperatures are slightly below the comfort band, but thatâ&#x20AC;&#x2122;s during the unoccupied hours when the internal heat gains are very low and the outdoor temperatures are very low.

In terms of Loads, with the use of these strategies, there has been a reduction in the Heating Loads when compared with the improved case (after the base case) (Figure 5.3.22), although the Cooling Loads are similar to the improved Case when the shading devices are applied.

Fig 5.3.22 Comparison of Loads for Reduced Window to Wall Ratios and Improved (Base) Case 105

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5.4 glazed facades (50% Window to wall)

Fabric: High Thermal Mass

Added Shading Devices

Added Night Ventilation

Fig 5.3.23 Strategies for each Step for Improvement in Thermal Performance

As in the daylight studies, a different layout was analysed, with all the four sides being glazed with a window to wall ratio of 50%, a similar study was done for the thermal model in order to check the performance of that case.

In terms of Loads, there can be increase in Heating Loads when compared with improved Case (improved from the base case) but there is a slight reduction in the heating loads when shading devices are applied with the Blinds as can be seen in the (Figure 5.3.24). The Cooling Loads remain the same in both the cases which are again higher than improved case.

The overheating has reduced to almost half with the introduction of night ventilation when tested without Shading and only high thermal mass which can be seen in appendix, but itâ&#x20AC;&#x2122;s still 2.5% higher then Improved (Base) Case (Figure 5.3.25).

Fig 5.3.24 Heating and Cooling Loads Comparison with the Improved (Base Case)

Fig 5.3.25 Overheating Hours with the Implementation of Night Ventilation 106

5.5 Window to wall reductions (4 facades) In order to understand, how a case where the window to wall ratios are reduced on all the four sides, ratios from the daylight analysis results were considered. It can be seen that in comparison with the 4 glazed facades, the Heating Loads have reduced substantially. Adding the shading devices with the blinds increases these loads slightly. (Figure 5.3.26) The Cooling loads have reduced a little then the case with 4 glazed facades (50% window to wall).

When comparing the heating loads with reduced window to wall ratio case of 3 facades, the heating loads are found to be slightly higher. However while comparing the cooling loads, it was found out that the case with reduced window to wall ratios at all 4 facades performs better than the 3 facades case (reduced window to wall ratio).

Fig.5.3.28 Different Strategies

Fig 5.3.27 Heating and Cooling Loads Comparison It can also be seen that with the help of Night Ventilation, Overheating has reduced substantially (Figure) although it is still almost double while comparing with 3 glazed faรงades case (reduced window to wall ratios) .

While comparing the 4 glazed faรงade case with the reduced 4 glazed facades case, the thermal performance has improved massively. So, in terms of a different layout as discussed in the daylight studies, the case of reduced (window to wall ratio) 4 glazed facades works much better.

Legend indicating the months which has overheating

Fig 5.3.28 Overheating Hours with Night Ventilation

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CONCLUSIONS FROM THERMAL ANALYSIS The problems such as high heating and cooling loads, uncomfortable internal environment in the workspace, which were encountered during the fieldwork and thermal analysis of the base case were rectified considerably while different strategies were applied. It was also found that improving the envelope and the use of shading devices had a very strong impact on the temperatures along with the Ventilation. Effect of internal heat gains is very important as it helps in increasing the temperatures during the winters but can help in causing overheating in the summer which can be counteracted by the use of Natural Ventilation and Night Ventilation, as they help in reducing overheating in summers massively.

Reduced window to wall ratio for 3 facades works the best for reduction of heating loads, while reduced window to wall ratio for 4 facades had similar heating loads with lower cooling loads the 3 reduced facades case. The use of these strategies has a good applicability in the future as well as they are very successful in reducing overheating which is 1 of an important concern for the future climate.

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CHAPTER-6 RESEARCH OUTCOMES AND APLICABILITY

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The research started with investigating the performances of London Office Buildings and certain problems and challenges were highlighted during this investigation through the literature as well as the fieldwork such as increase in Cooling Loads due to Climate Change which adds a risk to Overheating in the summers and High Heating Loads during the winters due to relatively colder climate in London. Through the fieldwork, the problem with improper daylight levels due to glare or more depth of the plan then the passive zone requirement causing higher dependence on Lighting Load. In order to tackle these issues certain strategies can be utilised which can help in achieving Thermal and Visual Comfort along with the reduction in Heating and Cooling Loads, resulting in lower energy consumption and lower CO2 emissions.

As mentioned above in the fieldwork, the occupants experienced Glare and insufficient daylight levels on their workspace which resulted in their dependence on Artificial Lighting hence increasing the Internal Heat Gains. Certain strategies can be applied to reduce the dependence on Artificial Lighting and in reduction of Glare and providing Optimum Daylight Levels which would in fact make occupants more productive. Also, there is a problem regarding the thermal discomfort which is caused by Lower temperatures in the winters and Higher temperatures in the summers then the expected range (comfort band) for the occupants. There are certain strategies that can be applied to improve the thermal and visual performance in London Office Buildings.

Some of the strategies are: •Use of Shading Devices such as Overhangs on the North and the East facades (although vertical shading devices works well but in the certain base case assumed during the study, overhangs performed better) along with Horizontal Shading Devices on the South and Vertical Shading Devices on the West Façade can help in shading these surfaces at the same time when combined with blinds (in case of highly glazed façade can help reduce the impact of glare massively).

•If there is layout where all the 4 facades are glazed, these shading devices can provide optimum daylight levels in the office building, these shading devices are not only effective for an open plan office buildings but even if they are deep plan offices, these can work successfully with keeping the services such as Core in the central part of the office which is comparatively darker, providing optimum daylight in the passive zone depth (6meters).

•The use of these shading devices not only has a good impact on daylight by providing optimum daylight levels in the spaces and shading the surfaces but also they play a crucial role in thermal performance of the building as in summers they help in reducing the temperature especially when combined with Night Ventilation and good Fabric. The combination of Night Ventilation works the best when combined with High Thermal Mass and during the winters, they help in keeping the temperatures a bit higher with combined with the blinds down at night as it reduces the infiltration further.

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• Night Ventilation can be provided by opening the windows at night but they increase the risk of security and increases the chance of dust and pollution. To overcome this, it can provided in the form of vents or shutters as they would allow better security and reduces the entrance of dust and pollution (Figure 6.1).

Figure 6.1 Use of Vents for Night Ventilation Source: http://passivesolar.sustainablesources.com As the heat loss during the night time is sustained by the thermal mass keeping the temperatures lower during the daytime.

•Using High Thermal Mass has the added advance that during the winters, they absorb the heat and along with being an airtight building which helps in keeping the temperatures higher.

As the heat loss during the night time is sustained by the thermal mass keeping the temperatures lower during the daytime.

•Using High Thermal Mass has the added advance that during the winters, they absorb the heat and along with being an airtight building which helps in keeping the temperatures higher.

Another factor which is important which designing and assigning passive strategies is the correct selection of window to wall ratio. The amount of glazing that is used in the building is very crucial for optimum daylight levels and better thermal performance, as it helps in reducing the loads and helps in providing better indoor temperatures.

Having an airtight building is very important as it helps in maintaining warmer temperatures in the winters.

•Having better quality of glass also helps in maintaining better temperatures in the building especially when major portion of the building is glazed.

With the utilization of these strategies, better thermal and visual performances of the office buildings in London can be achieved. With the help of these strategies, substantial reduction in Loads can be achieved, at the same time it helps in reducing the risk of overheating during the summers in the office buildings in London.

These strategies are effective for their performance in the future as they are effective in reducing the overheating which is one of the expected problem of the future, hence reducing the cooling loads, although there is not a major difference in the reduction of loads as they are currently with the implementation of these strategies.

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AA 2015-16 MSC. SUSTAINABLE DESIGN ARCHITECTURE References: • Ekins, P. and Lees, E (2008). The impact of EU policies on energy use in and the evolution of the UK built environment.

Energy Policy, 36(12), pp. 4580–4583.

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Renewable and Sustainable Energy Reviews; (12): 2117-2139 Santamouris, M. (ed.) (2007). Advances in passive cooling: buildings, energy and solar technology series. Pg 18-19, 140-153. United Kingdom: Earthscan Publications. Reference • Killip, G. (2005). BUILT FABRIC & BUILDING REGULATIONS, Background material F 40% House project. Environmental Change Institute University of Oxford • UK Climate Impacts Programme. 2015. Beating the Heat. [ONLINE] Available at:http://www.ukcip. org.uk/wp-content/PDFs/Beating_heat.pdf. [Accessed 15 April 2016].

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• Vinyl replacement windows, MI, Michigan, energy saving vinyl replacement windows, Michigan, energy star vinyl windows in Michigan, energy efficient http://www.tailormadewindows.com/replacement_vinyl_windows_mi_michigan.php • INSPiRe renovation solutions for residential and office buildings - designing buildings Wiki http:// www.designingbuildings.co.uk/wiki/INSPiRe_renovation_solutions_for_residential_and_office_buildings • Trends in office internal gains and the impact on space heating and cooling • Low carbon tech 2009 Jenkins 134-140 • Excerpt taken from https://www.wbdg.org/design/office.php • What office design trends to expect in 2016 (http://blog.spectrumworkplace.co.uk/what-officedesign-trends-to-expect-in-2016) • (http://www.exeter.ac.uk/media/universityofexeter/research/newsandevents/newsandeventsarchive/ Overheating-1.pdf) • The importance of office internal heat gains in reducing cooling loads in a changing climate (http://ijlct.oxfordjournals.org/content/4/3/134.full) • Nicol, F., and Humphreys, M. A. (2009). New standards for comfort and energy use in buildings.

Building Research & Information, 37(1), 68–73. [Online] Available from [Accessed 24th May 2016] • Nicol, F., Humphreys, M. A., and Roaf, S. (2012). Adaptive thermal comfort : principles and practice.

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• Nicol, F., and McCartney, K. (2001). Final Report (Public) Smart Controls and Thermal Comfort (SCATs). Report to the European Commission of the Smart Controls and Thermal Comfort project. Oxford: Oxford Brookes University.

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• http://www.e-architect.co.uk/england/woodland-trust-headquarters • KLH: Woodland trust HQ 2011| KLH: Woodland Trust HQ http://www.klhuk.com/ portfolio/commercial/woodland-trust-hq.aspx#ixzz4K7dp4eSL • http://www.klhuk.com/media/9053/bd260310_solutions%20sustainability_’woodland%20trust%20hq’%20vs1.pdf, 2010.

• Woodland Trust http://fcbstudios.com/work/view/woodland-trust-headquarters,2010 • BD Online Bradley woodlands http://www.bdonline.co.uk/feilden-clegg-bradley-woodlands-trust-headquarters-grantham/5019837.article, 2011.

• Innovate UK https://connect.innovateuk.org/documents/3270542/3713354/Woodland%20Trust%20Case%20Study?version=1.5, 2014.

• A model for the 21st century BRE, http://projects.bre.co.uk/envbuild/envirbui.pdf • New environmental office, BRE | work 1996, http://fcbstudios.com/work/view/new-environmental-office-bre • BRE’s environmental building, 2000 http://projects.bre.co.uk/envbuild/ • The environmental building the building research establishment (BRE) office building the environmental building; http://www.webpages.uidaho.edu/arch504ukgreenarch/casestudies/bre2.pdf • Brown, G. Z. and Mark Dekay. Sun Wind and Light. 2nd ed. John Wiley & Sons Inc., 2001.

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• The future of heating: A strategic framework for low carbon heat in the UK, 2012 (https://www.gov.uk/government/uploads/system/uploads/attachment_data/ file/48574/4805-future-heating-strategic-framework.pdf) • BRE’s Environmental Building: Energy Performance in Use C. Ní Riain1 BSc. (Hons) J. Fisher2 BSc. (Hons) F. MacKenzie2 MSc., BSc. (Hons) J. Littler1 MA, PhD, CEng, MCIBSE, MCIOB, MASHRAE 1 Research in Building Group, Department of Architecture, University of Westminster, 35 Marylebone Road, London, NW1 5LS, UK. http://ijlct.oxfordjournals.org/ content/4/3/134.full)

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A1: SPOTMEASUREMENT: INDOOR TEMPERATURES

A2: SPOTMEASUREMENT: CONDITIONS

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A3: SPOTMEASUREMENT: RELATIVE HUMIDITY

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