Daylight & Thermal Performance of Office Buildings in Ankara

DAYLIGHT & THERMAL PERFORMANCE OF

office buildings IN ANKARA AA E+E ENVIRONMENT & ENERGY STUDIES PROGRAMME ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE MSC SUSTAINABLE ENVIRONMENTAL DESIGN GRADUATE SCHOOL DISSERTATION PROJECT 2015 I 2016 ECE DURMAZ SEPTEMBER 2016

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ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

ECE DURMAZ

3

ABSTRACT After the oil crisis in 1973, a global concern over the energy usage of the building sector began to rise. However, the average energy consumption of the current building stock in Turkey is still excessive since there was not any regulation regarding the thermal insulation issues until the recent years (Cakmanus, 2007). According to TurkStat (2013), in 2015 alone, 467 office buildings got construction permits in Ankara. Therefore, the bioclimatic approach gets more important for office buildings to minimize unnecessary energy consumption.

Unfortunately, the existing literature fails to provide a general rule of thumb for Ankara and to reveal possible energy savings that can be obtained through passive design measures. Therefore, this dissertation aims to provide guidelines for the bioclimatic designs to achieve occupant comfort and reduce energy consumption of the office buildings in Ankara.

The evolution of working environments, new trends and tendencies were reviewed by analysing the features of different generations. According to the related findings in the literature review, a current and two possible future scenarios were created. The passive design strategies were applied and tested for different construction typologies and orientations in a hypothetical urban context of Ankara. The research revealed that the free-running period of a typical office space could reach up to 72% of the occupied time with a significant reduction in cooling consumption when passive measures were applied.

Fig0.1 Photo on the cover page Source: www.123rf.com, 2016

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ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

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DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

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AUTHORSHIP DECLARATION FORM AA SED

ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

PROGRAMME

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

COURSE TUTOR

SIMOS YANNAS

SUBMISSION

DISSERTATION

TITLE

DAYLIGHT & THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

NUMBER OF WORDS

18090

(EXCLUDING FOOTNOTES & REFERENCES)

STUDENT NAME

ECE DURMAZ

DECLARATION: “I certify that the contents of this document are entirely my own work and that any quotation or paraphrase from the published or unpublished work of others is duly acknowledged.”

SIGNATURE

DATE

SEPTEMBER 16, 2016

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MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

TABLE OF CONTENTS

1. INTRODUCTION

13

16

1.1 METHODOLOGY

2. THEORETICAL RESEARCH

19

2.1 CURRENT SITUATION IN TURKEY

21

2.2 EVALUATION OF WORKING ENVIRONMENTS

23

2.2.1 PAST

23

2.2.2 PRESENT

26

2.2.3 FUTURE

30

2.3 FACADE DESIGN AND NATURAL DAYLIGHT

35

2.4 ORIENTATION AND SHADING STRATEGY

38

2.4.1 SOUTH FACADE

39

2.4.2 EAST & WEST FACADES

40

2.4.3 NORTH FACADE

41

3. BUILT PRECEDENTS

45

3.1 EAWAG FORUM CHRIESBACH

48

3.2 ETRIUM OFFICE BUILDING

52

3.3 ESER GREEN BUILDING

56

3.4 GSW HEADQUARTERS

60

3.5 KFW WESTARKADE

64

3.6 WMO HEADQUARTERS

68

4. CONTEXT & CLIMATE

77

4.1 CONTEXT

79

4.2 TEMPERATURE & COMFORT BAND

80

4.3 SOLAR RADIATION

82

4.4 WIND

83

4.5 DEFINING HYPOTHETICAL CONTEXT

84

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

ECE DURMAZ

5. ANALYTIC WORK

89

91

5.1 DAYLIGHT ANALYSIS PART I: SELECTING SHADING DEVICE

5.1.1 SOUTH

92

5.1.2 EAST

94

5.1.3 WEST

96

5.1.4 NORTH

98

5.2 DAYLIGHT ANALYSIS PART 2: DETERMINING THE DEPTH

100

5.2.1 SOUTH

102

5.2.2 EAST

104

5.2.3 WEST

106

5.2.4 NORTH

108

5.3 THERMAL ANALYSIS

110

5.3.1 SOUTH

114

5.3.2 EAST

124

5.3.3 WEST

134

5.3.4 NORTH

144

6. OUTCOMES & DESIGN APPLICABILITY

153

6.1 COMPARISON OF THE FINDINGS

154

6.2 OUTCOMES

155

6.3 DESIGN APPLICABILITY

156

7. CONCLUSIONS

163

8. REFERENCES

167

9. APPENDICES

171

9.1 LITERATURE REVIEW

172

9.2 CONTEXT & CLIMATE

173

9.3 ANALYTIC WORK

174

9.4 DESIGN APPLICABILITY

182

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ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

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DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

TO MY FAMILY...

ECE DURMAZ

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MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

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ACKNOWLEDGEMENTS I would like to express my sincere gratitude towards the entire staff of AA SED Programme for their support, especially Prof. Simos Yannas for his personal guidance and critical comments, and Herman Calleja for his feedback and technical support to develop this dissertation.

I would also like to thank the Architectural Association School of Architecture for the bursary I was awarded to attend the AA SED MSc course 2015-2016.

Special thanks are also to be offered to my SED colleague Rafael Alonso Candau with whom I have had crucial discussions regarding future trends in offices.

I would like to acknowledge Serhat Asik for proofreading this dissertation.

Finally, I would like to express my deepest gratitude to my family, especially my mother Beyhan Durmaz and my brother Ozer Durmaz, for their constant encouragement and Berkay Caliskan for his unconditional support.

1. INTRODUCTION METHODOLOGY

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DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

INTRODUCTION The increasingly growing energy use has raised concerns over the consumption of energy resources, and has a crucial environmental impact on global warming, ozone depletion, and climate change due to high amount of CO2 emissions. The total contribution of the commercial buildings to energy consumption has risen over the years and exceeded the other main sectors (IEA, 2006). Unfortunately, Turkey has shown a similar trend in energy use in that the non-renewable resources are mainly used for electricity generation (Fig1.1). The demand explosion in recent years has caused the share of the commercial buildings in total electricity consumption to increase. According to the TEDAS statistics, this value reached 26.2% in 2014. With the invention of air conditioning in the early 1900s, the approach for architectural designs changed, and the buildings relying on “the artificial climate” rather than the exterior climate started to be constructed. Following a fully glazed facade typology, recent commercial buildings respond more to the developer’s desire than to the user’s need and sustainability principles.

Facades are the intermediary elements determining the relation of interior space with the outside, and is of great importance due to their effect on energy consumption.

A well-designed facade with a proper shading strategy can improve daylight quality, and also lower the energy consumption for heat gain and cooling in buildings up to 5% or 15% depending on the amount of the fenestration (Prowler, 2014). Besides the environmental benefits, there are numerous studies revealing that a well-illuminated interior design and a pleasant view have positive effects on workers’ performance and productivity (Heschong, 2003). According to the findings of a questionnaire investigating the employee comfort, Markus (1967) states, more than 95% of the respondents preferred to work under daylight instead of electric lighting. Moreover, the workers sitting away from the windows had more complaints compared with the employees sitting next to the windows.

Developing technologies and new trends in offices change the way people work and interact with each other. They require new spaces that can adapt to future working environment tendencies and climates. Unfortunately, the architectural style of existing fully glazed buildings has been driven only by aesthetic understanding where changing trends of working environment have been neglected. This research focuses on how passive design strategies and new trends in the working environment affect the office layout, building design and occupant comfort.

BIOGAS + OTHERS 0.6%

GEOTHERMAL 1.3%

HYDRAULIC 25.8%

NATURAL GAS + LNG 37.8% WIND 4.4% FUEL OIL 1.6%

COAL + LIGNITE 13.2% IMPORT COAL 15.2%

ELECTRICITY GENERATION (2015): 259.7 BILLION KWH Fig1.1 Sources for Turkey’s electricity production in 2015 Source: After TEIAS, 2016

ECE DURMAZ

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Table1.1 Electricity usage according to user groups in 2014 Source: After TEDAS, 2014 CONSUMPTION

SUBSCRIBER

SUBSCRIBE GROUP

MWH

RATIO (%)

NUMBER

RATIO (%)

RESIDENTIAL

46,189,693

22.3

31,388,451

81.7

COMMERCIAL AND PUBLIC BUILDINGS

54,303,872

26.2

5,905,040

15.4

INDUSTRIAL BUILDINGS

97,777,468

47.2

203,178

0.5

AGRICULTURAL IRRIGATION

3,919,199

1.9

561,948

1.5

STREET LIGHTING

3,942,641

1.9

285,807

0.7

OTHER

1,242,285

0.6

63,909

0.2

TOTAL

207,375,0,78

100

28,408,333

100

The research questions are as follows: How has the office environment evolved?

What are the future scenarios? Is the current layout adaptable to the future climate?

What is the impact of orientation driven design in terms of daylight and thermal comfort?

What is the effect of different envelopes on heating and cooling demand in the continental climate?

How should be the ventilation strategy determined in accordance with the envelope and the climate?

This dissertation aims to focus on the possible design strategies for office buildings in Ankara to reduce the total energy consumption while providing adequate level of natural light, proper ventilation, and thermal comfort. The goal of this dissertation is to provide a sustainable design handbook for Ankara to reduce energy demand.

1.1 METHODOLOGY The structure of this dissertation is as follows: This dissertation starts with the evolution of office environments, and defines current and two possible future scenarios. Then, it draws an outline for the window configuration and shading strategies regarding the facade orientation. In Chapter 3, six built precedents are critically investigated based on a literature review to collect useful information about the sustainability strategies. The next chapter focuses on the context, current and future climate scenarios, and comfort studies in Ankara. Various parameters including diurnal temperature difference, solar radiation levels with respect to orientation and comfort zone calculations help to discover potential passive strategies. Afterwards, a shoe-box building is prepared to select shading devices and optimize depth of space to guarantee the lux required. In order to have a holistic study, 3 different constructions, matching with Turkish standards, are investigated to reveal the impact of context, shading devices, night shutters, ventilation strategies, and internal gains on occupant comfort and heating/cooling consumption. Finally, the outcomes of daylight, and thermal studies regarding the orientation are summarized to assess the applicability of the design.

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

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2. THEORETICAL RESEARCH PAST, PRESENT AND FUTURE TRENDS WINDOW CONFIGURATION & SHADING STRATEGIES

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ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

2.1 CURRENT SITUATION IN TURKEY The building sector is one of the most energy consuming sectors. According to Turkish Statistical Institute’s database (2016), the number of the buildings was 4.3 million in 1984 and this value reached to 7.8 million with an increase of 78% in 2000. In 2015 alone, 467 office buildings obtained construction permits in Ankara (TurkStat, 2016).

Therefore, energy management regulations and policies are of crucial importance in order to combat the excessive amount of energy consumption.

The thermal insulation regulation, TS 825, for decreasing heating and cooling energy usage in residential and non-residential buildings was released in May 1998, and became obligatory for all the new buildings to be constructed after June, 2000.

According to the Association for Energy Efficiency (2015), the energy used for heating and cooling constitutes more than one third of the energy consumption in Turkey. The main reason behind this is that the buildings are either not insulated or their insulation level is not sufficient. It is reported that almost 90% of the buildings in Turkey are not adequately insulated (Association for Energy Efficiency, 2015). This situation causes excessive use of energy across the country. Therefore, it is aimed to decrease energy intensity by nearly 20% until 2023 (Energy Efficiency Law, 2007).

ISTANBUL

ANKARA IZMIR

1ST REGION

3rd REGION

2

4th REGION

ND

REGION

Fig2.1 4 regions in Turkey with different regulations Source: After TS 825 Thermal Insulation Requirements for Buildings, 2008

Table2.1 Recommended u-values for the building envelope (Ankara is in the 3rd Region) Source: After TS 825 Thermal Insulation Requirements for Buildings, 2008 



















































ECE DURMAZ

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ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

According to a study conducted by Ganic and Yilmaz (2014), the current office building stock meeting the minimum standards consumes 330 kWh/m2 primary energy in Ankara. Half of this energy is used for heating and cooling purposes. As seen in the figure below (Fig2.2), there is a huge potential for energy savings with the implementation of some retrofit packages. These results can be improved more when passive strategies are considered during the design process. Hence, it is crucial to study sustainable design measures to minimize heating and cooling consumption, and provide a good working environment for the occupants.

 HEATING SET POINT: 21 C COOLING SET POINT: 26OC

 



 



 



 





 





 





 





 



 







 





 

 



CHILLER COP: 1.5





NATIONAL PRIMARY ENERGY CONVERSION FACTORS: 1 FOR NATURAL GAS 2.36 FOR ELECTRICITY





HVAC SCHEDULE: 09:00 - 18:00, WEEKDAYS



O

 

 

Fig2.2 Inputs and factors used for calculations (left) and graph showing primary energy use of an office building in Ankara as a result of renovation packages (right) Source: After Ganic & Yilmaz, 2014

Table2.2 Retrofit packages Source: After Ganic & Yilmaz, 2014  







































































































































































  



 

 



























































































































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2.2 EVALUATION OF WORKING ENVIRONMENTS The best way to define the working environment of next generation is analysing past and current trends, where construction styles, occupant behaviour, equipment and lighting technology have been altered significantly. Oldfield, Trabucco and Wood (2008) have categorized the performance evaluation of office buildings in 5 periods. These generations were reinterpreted for temperate climates, and new categories were created for the past, present and future scenarios.

2.2.1 PAST

GENERATION 1: NATURALLY VENTILATED MASONARY BUILDINGS The buildings in this period required little energy since technological systems such as HVAC, and fluorescent lighting had not been developed. The energy was mainly used for heating, and consumed while being transmitted between the floors. Ventilation was applied to the spaces via opening the windows, and lighting levels were quite low, 20 – 45lux (Osterhaus, 1993). The window-to-wall ratio (WWR) was quite small, and constituted 20 – 30% of the facade area, compared to the contemporary buildings with a glazing area of 50-70% (Oldfield et al., 2008). The bulky shape and relatively low surface to volume ratio maximized the rentable area, but restrained natural light penetration deep into the working space. Although the buildings suffered from poor air tightness and infiltration due to single glazing, the compact form and thermal mass application were effective while creating comfortable spaces (Oldfield et al., 2008) (Fig2.3).

The buildings of this era showed good thermal performance with the help of their shape and solidity. However, they still required a massive refurbishment process to introduce HVAC system and provide adequate lighting. Additionally, low levels of natural daylight reduced the performance and satisfaction of the workers.



 Low lux levels

20 - 90 lux (Ostherhaus, 1993)

Low equipment loads (Oldfield et al., 2008)

Facade u-value

2.0 - 3.0 W/m2K (Oldfield et al., 2008)

Small windows

30% of the wall area (Oldfield et al., 2008)

Naturally ventilated Poor air tightness

due to single glazing

Fig2.3 Typical features of Generation 1 buildings

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Fig2.4 Generation 1 offices in 1930s are characterized by low equipment gains Source: Digital Library of University of Kentucky (left), wikipedia.org 2015 (right)

2.2.1 PAST

GENERATION 2: FULLY GLAZED BUILDINGS

GENERATION 2 EXAMPLE BUILDING

This generation was characterized with the buildings turning into hermetic glass boxes. The new typology had much higher glazing ratio reaching up to 70% of the facade area. Arnold (1999) mentions in ASHRAE Journal about Air Conditioning in Office Buildings After World War II that Lewer House was one of the first buildings that HVAC system was fundamental for maintenance. He also stresses that this globalized typology was adopted by the UK in 1960s, without climatization. However, they all failed to provide comfortable working environment, and it is understood that this typology requires air-conditioning irrespective of the climate.

Emek Building Ankara I Turkey

In Ankara, 22-storey Emek Commercial Building, completed in 1965, has a single glazed curtain facade with fixed windows. Initially, the radiator system was used only for heating, but cooling and ventilation systems were ignored. In 1991, a fan coil cooling system was added due to the overheating (Cakmanus, 2007). Ugursal (2003) stresses that the Emek Building consumes 53 kWh/m2 for heating and 29 kWh/m2 for cooling.

The total consumption reaches up to 236 kWh/m2 when artificial lighting and other loads are considered. The interesting finding of this study was when natural ventilation was applied throughout the year, the cooling load was eliminated, but the heating load got doubled (Fig2.5 left). On the other hand, when ventilation was integrated from 

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Fig2.5 Annual energy use of Emek Buıilding when ventilation applied for whole year (left), total energy use between May 1st to September 30th when natural ventilation is integrated for only summer months (right) Source: After Ugursal, 2003

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Fig2.6 Photographs showing Generation 2 offices between 1960s - 1970s Source: Asher 2011 (left), babyboomerdaily.com 2013 (right)

May to September, cooling was no longer required although there would still be a small amount of heating load penalty (Fig2.5 right). Thus, Ugursal (2003) suggests that instead of introducing a fully naturally ventilated office in Ankara, mixed mode ventilation strategies could be considered where passive design measures can be supported with HVAC systems.

To summarize, overheating issues resulting from the fixed windows, and energy consumption in general were the major problems of the office buildings in this period (Fig2.7). These problems can be solved by a combination of passive measures and means of technology.

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 Mechanical ventilation Fully reliance

Fluorescent lamps - high lux levels 25 W/m2 (Verderber&Rubinstein, 1982) 800 - 1000 lux (Osterhaus, 1993)

Facade u-value

3.3 - 4.2 W/m2K (Oldfield et al., 2008)

Colored single glazing

50% - 70% of the wall area (Oldfield et al., 2008)

Fixed windows

Fig2.7 Generation 2 buildings are hermetically sealed boxes totally reliant on HVAC systems

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2.2.2 PRESENT GENERATION 3 EXAMPLE BUILDINGS Armada Office Tower Ankara I Turkey The Qube Building London I United Kingdom

GENERATION 3: IMPROVEMENT OF FACADE After Energy Crises in 1973 and 1979, single glazed curtain facades were criticized for poor energy performance. In response, the glass industry manufactured several glazing types that could limit unwanted heat gain in summer while reducing heat loss in winter. During this period, low-e and argon filled glass was produced. Therefore, the u values of the envelope were reduced to 0.75 – 1.5W/m2K compared to the buildings in the second generation with 3 - 4.2W/m2K (Oldfield et al., 2008). Artificial lighting loads have been reduced since clearer glazing was used again. This generation is characterized with high internal gains due to computerization of offices.

A contemporary example from Ankara is Armada Office Tower, completed in 2002.

The building was originally designed to be naturally ventilated via a double facade, however, it was changed to a single facade to decrease the construction costs.

Because of the fixed glazing, the building currently relies on a fan coil system for thermal comfort. Durmaz (2016) mentions, A Tasarim Mimarlik Office, which is on the 9th floor of this building, has an annual heating and cooling consumption of 22 kWh/ m2a and 38 kWh/m2a respectively. Despite the high equipment power density reaching up to 23 W/m2, the cold winter period in Ankara and north-east facing orientation are the main reasons of relatively high heating loads (Fig2.10 left).

            

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Fig2.8 Monthly heating and cooling breakdown of HOK Office in the existing situation Source: After Alonso et al., 2015

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Fig2.9 Average daily breakdown of internal and solar gains in HOK Office Source: After Alonso et al., 2015

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Fig2.10 A Tasarim Office in Armada Tower, Ankara suffers from overheating problem created by high equipment load (left). Atrium of HOK Office, London provides an alternative working and resting space. However, this space does not function in terms of sustainability measures due to fixed windows on the facade (right) Source: www.hok.com (right)

Another example, is HOK Office in the Qube Building, London. The building has an atrium, however, it does not function properly since windows on the facade are fixed (Fig2.10 right). Alonso, Dias, Durmaz and Eid (2015) stated that even during the winter months, cooling is necessary to prevent office from overheating due to high internal gains, and heating is rarely required (Fig2.8). In the breakdown of the internal gains, it is obvious that the predominant load results from equipment electricity usage (Fig2.9).

Being in a dense urban area, the impact of solar radiation on the indoor temperature is negligible for this specific case.

During this period compact fluorescent lamps became widespread since it is an easy and effective solution. According to the statistics in Turkish National Journal (2012) the fluorescent lamp sales were around 4 million dollars in 2004. However, it reached to 20 million dollars in 2007, and 32 million dollars in 2008.

The main problem in this period was related with rapidly rising equipment loads (Fig2.11). Technological developments and computerization of the offices had a negative impact on energy consumption. Currently, the majority of the offices in Ankara follow the trends from this period. 

 Mechanical ventilation Fully reliance

Equipment loads

32 -54 W/m2 until late 1980s 10.8 - 25 W/m2 after 1990s 20% - 30%of all energy consumption (ASHRAE Technical Feature, 2011)

Fluorescent lamps - high lux levels 12 - 19 W/m2 (Liebel&Brodrick 2005) 300 - 1000 lux (Osterhaus, 1993)

Facade u-value

0.9 - 1.5 W/m2K (Oldfield et al., 2008)

Low-e double glazing

40% - 85% of the wall area (Oldfield et al., 2008)

Fixed windows

Fig2.11 Typical features of Generation 3 buildings. Although facade performance has improved, computerization of offices has a negative impact on cooling loads

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2.2.2 PRESENT GENERATION 4.1 EXAMPLE BUILDINGS* Forum Eawag Chriesbach Zurich I Switzerland Etrium Building Cologne I Germany Eser Green Building Ankara I Turkey

GENERATION 4.2 EXAMPLE BUILDINGS* GSW Headquarters Berlin I Germany KFW Westarkade Frankfurt I Germany WMO Headquarters Geneva I Switzerland

GENERATION 4: INTEGRATION OF NATURAL VENTILATION At the beginning of the 21st century, an environmentally conscious approach began to emerge. The common characteristics of this approach are applying high-tech and low-tech systems to provide natural ventilation and reduce energy consumption.

While low rise buildings such as Forum Eawag Chrisbach (Zurich, 2005) and Etrium Office Building (Cologne, 2008) are using a ventilation system via operable windows and atrium, the high rise buildings such as The Commerzbank (Frankfurt, 1997), GSW Headquarters (Berlin, 1999) and KfW Westarkade (2010, Frankfurt) are taking the advantage of double skin facades for natural ventilation (Fig2.12 – Generation4.1, Fig2.15 - Generation4.2).

The passive zone depth regarded in the design stage helps to provide the interior with adequate daylight. Additionally, energy efficient bulbs and LEDs, becoming widespread, plays an important role in the reduction of artificial lighting loads.

In this period, cooling load consumption is reduced significantly by using the potential of effective natural ventilation strategies. For instance, Alonso et al. (2015) stresses that cooling loads of HOK office could be reduced up to 78%, if stack ventilation through atrium were applied (Fig2.14).

This generation is quite crucial since the energy conscious designs have started to take place, and the buildings do not completely rely on mechanical air conditioning.

For example, GSW Headquarters can be in favour of free-running operation for 70% of the time (Iyengar, 2015).

*Generation 4.1 and 4.2 buildings will be analyzed in detail in Chapter 3.

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LED

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7 - 12 W/m2 (CIBSE Guide A, 2005) 300 - 500 lux (Osterhaus, 1993)

10.8 - 15 W/m2 (ASHRAE Technical Feature, 2011) up to 50% of all energy consumption

Facade u-value

0.9 - 1.1 W/m2K (Oldfield et al., 2008)

Low-e double glazing Various glazing area

Natural ventilation Solar protection

Fig2.12 Typical features of low rise Generation 4.1 buildings. Usage of mixed mode ventilation reduces energy consumption significantly

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Fig2.13 3-sided atrium of Eawag Forum Chriesbach expels warm air with stack effect (left) and creates a space for social interaction and working (middle). In this generation low-tech and high-tech systems are used to generate building’s own energy (roof top of Etrium, Cologne - right) Source: Bob Gysin + Partner BGP 2006 (left), www.eawag.ch 2016 (middle), www.menerga.pl (right)

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Fig2.14 Cooling loads of HOK Office could be reduced significantly by applying natural ventilation through atrium Source: After Alonso et al., 2015

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7 - 12 W/m2 (CIBSE Guide A, 2005) 300 - 500 lux (Osterhaus, 1993)

10.8 - 15 W/m2 (ASHRAE Technical Feature, 2011) up to 50% of all energy consumption

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0.9 - 1.1 W/m2K (Oldfield et al., 2008)

Natural ventilation through the double facade system Various glazing area

Fig2.15 High rise Generation 4.2 buildings use double facade system to integrate natural ventilation since upper floors are exposed to high wind speed. Therefore incoming air velocity can be controlled.

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2.2.3 FUTURE SCENARIO

EQUIPMENT & LIGHTING LOADS Offices are characterized by high internal gains. Depending on the type of offices, working hours and trends, the internal gains may show great variety. This is quite crucial since the office layouts, passive strategies, and HVAC requirements change accordingly.

CIBSE Guide A (2016) defines the equipment load of a building as 12–15 W/m2 for general offices, and 18-25 W/m2 for offices in city centres. According to Turkish Thermal Insulation Regulation (TS 825), internal gains are accepted as 5 W/m2 for residential buildings and 10 W/m2 for buildings which have high energy use such as office buildings. However, these values are defined for the whole building, not specified for the space type. Considering the small rooms without appliances to be same as the workstation areas create a contradiction between the analytic works and real life cases. Cakici (2013) criticized this condition and proposed 5 different internal gain options that can be calculated according to the zone type in Energy Performance Evaluation Program (EnAd). In Armada Office Tower example, CIBSE Guide A values reflect Ankara’s current situation in a more realistic manner.

Table2.3 Comparison of suggested equipment and lighting power densities 

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   

FUTURE

GENERATION 5.1: ENERGY CONSCIOUS   

 



 



Fig2.16 Working environment of future “energy conscious” offices Source: After Johnston et al., 2011



 

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

In “Trends in Office Internal Gains and the Impact on Space Heating and Cooling” Johnston, Counsell and Strachan (2011) claim two possible future scenarios; one where developments in technology would reduce equipment and artificial lighting loads, and another where bigger and multiple monitors, media walls would cause a massive increase in energy consumption (Fig2.16, Fig2.18). In both scenarios, the lighting loads would decrease from 7 W/m2 to 4 W/m2 since LEDs are substituting for the fluorescent lamps. Innovation in technologies indicates that the equipment will be more energy efficient in the near future. Since adaptation of offices to these changes would take time, the equipment load of the energy conscious scenario was defined as 6 W/m2 in the analytic work.

The techno explosion scenario is mainly supported with a study showing changes in monitor sizes between 1999 and 2011. The research indicated that there is a clear trend towards larger and multiple screens (Colvin, Tobler and Anderson, 2011). Additionally, Colvin et al. (2011) stress that working with double monitors improves employer’s productivity by 40%. Considering future equipment to be more energy efficient, Johnson et al.’s claim - 33 W/m2 - is found to be too extreme. Hence; appliance loads of techno era was accepted as 22 W/m2 in the further studies (Fig2.17).

      





 

                        

Fig2.17 Equipment usage daily profile for current and future scenarios Source: After Johnston et al., 2011

FUTURE

GENERATION 5.2: TECHNO ERA   

  

 

 

  





Fig2.18 Equipment gains would be higher in techno explosion scenario Source: After Johnston et al., 2011

  

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2.2.3 FUTURE SCENARIO

OCCUPANCY PROFILE During the Generation 3 and 4, detailed occupancy studies were held for the first time. According to Occupier Density Study Report (2013) which analysed 381 properties and more than 2,400,000m2 office spaces, the mean occupancy density is 10.9 m2/ workstation. CIBSE Guide A (2016) defines this value separately for the offices in general and the city centres, 12-16m2/person and 6-10m2/person respectively. The occupant density of A Tasarım Office, 11m2/person, shows that the occupancy patterns of the office buildings in Ankara comply with the findings of Occupier Density Study Report. On the other hand, the density value jumps up to 7m2/person when only the open office space is considered (Durmaz, 2016). Not taking the space type into account creates similar problems as in the equipment load calculations (Table2.4).

Expecting utilization rates to increase, many firms have introduced the flexible open layout (Fig2.19). However, Occupier Density Study Report (2013) indicates that the maximum utilization is around 80% of full occupancy. This finding is supported

by Duarte-Roa’s (2013) study held in 18,000m2 building serving for various sectors.

The data, collected from 629 occupancy sensors for 2 years, shows that profiles show great variety for open and cellular offices, and they are, in both cases, much lower than ASHRAE Standard 90.1 (Fig2.20). This range significantly affects the internal gains, and consequently the inputs of analytic works since the occupancy and equipment heat gains are linked with density. Therefore, effective density and maximum utilization rates are much more reliable than just considering workstation density.

Table2.4 Comparison of occupant densities from different sources 





 



 



  





 

 













 









 

Fig2.19 Intensification of space use. In this example, number of people supported in the same area is increased by 33%.

Source: After Occupier Density Study Report (2013)

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

To increase effective density in the offices, the hot desking model was introduced in 1990s. However, this model was not adopted on a vast scale since technological requirements to make it work were not fully satisfied. Nowadays, the interest on this trend has been renewed due to the high budgetary pressure on employees and rising number in mobile workforce. This “spaceless growth” can decrease space need by 20 – 30% by increasing the utilization rate (Occupier Density Study Report, 2013).

From employer’s perspective, it has both benefits and shortcomings. Although some workers are happy with being flexible, others still need their personal space/desk.

This problem can be solved by assigning both fixed workstations and hot desking to the office space. Therefore, the occupancy pattern for future scenarios was defined according to the mixed layout (fixed workstations + hot desking) for the further analytic studies.

        

  







Fig2.20 Comparing ASHRAE 90.1.2004 references to Duarte-Roa’s findings Source: After Duarte-Roa, 2013

Fig2.21 Advancement in technology has fed demand for a flexible working environment Source: Occupier Density Study Report (2013)

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Table2.5 Comparison of generations based on the literature findings Source: After Oldfield, Trabucco and Wood, 2008

GENERATION 3

From the rise of an environmental consciousness in 1997 to the present day

GENERATION 4

Expected future scenario

GENERATION 5

FUTURE SCENARIO

GENERATION 2

From Energy Crisis in 1973 to the present day

PRESENT

GENERATION 1 From the development of the glazed curtain facade in 1951 to Energy Crisis in 1973

Various

PAST

From 1930s to the development of the glazed curtain facade in 1951

Various

Low-e double glazing, triple glazing

40% - 85% Low-e double glazing

Low-e double glazing, triple glazing

0.12 - 1.1 W/m2K (airtight envelopes due to advancements in construction sector)

50% - 70%

0.9 - 1.1 W/m2K

Mixed-mode

30%

Mixed-mode

150 - 300 lux (monitor based works)

GLAZING PERCENTAGE

Mechanical ventilation

300 - 500 lux

4 - 10 W/m2 (LED)

Single glazing (tinted)

Mechanical ventilation

300 - 1000 lux

7 - 12 W/m2 (LED)

4 - 8 W/m2 (Energy conscious scenario) 15 - 33 W/m2 (Techno era scenario)

Single glazing

Natural ventilation

800 - 1000 lux

12 - 19 W/m2 (fluorescent lamps)

10.8 - 15 W/m2

Yes

GLAZING TYPE

VENTILATION TYPE

20 - 90 lux

25 W/m2 (fluorescent lamps)

32 - 54 W/m2 until late 1980s 10.8 - 25 W/m2 after 1990s

Yes

0.9 - 1.5 W/m2K

INTERIOR LIGHTING LEVELS

-

-

No

2.5 - 4.2 W/m2K

LIGHTING POWER DENSITY

-

No

2.0 - 3.0 W/m2K

EQUIPMENT POWER DENSITY

No

FACADE U-VALUE

ON SITE ENERGY GENERATION

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

2.3 FACADE DESIGN AND NATURAL DAYLIGHT Besides the internal gains, the facade parameters including WWR, glazing types, exterior wall u-value and shading devices, have a huge impact on cooling loads and occupant comfort in office spaces. The energy conscious scenario shows that internal gains in the offices could drop in the future, therefore, building envelopes could play a more crucial role in energy consumption. While designing a sustainable office for future, it is important to control unwanted solar gains without deteriorating daylight quality of the space.

The usage of daylight requires to follow some design standards and should provide the occupants with control over the shading devices in order to increase user satisfaction. According to the data in “Tips for daylighting with Windows” released

by U.S. Department of Energy (Robinson, Selkowitz, 2013), a well-lit pleasant working atmosphere may decrease absenteeism and improve workers’ performance.

Additionally, the cooling energy load caused by the appliances and electricity lighting can be decreased by 40%.

The daylight requirement of computerized working areas is less demanding than those for offices having document based tasks but nevertheless 300 lux and a low glare on working plane are required (Ruffles, 2005). For permanently occupied areas, the minimum illumination level is set at 200 lux by the Health Safety Executive (1994).

On the other hand, temporarily occupied spaces such as circulation areas can have lower values. Hence, circulation space can be designed far from the facade as a separate control zone to decrease electricity demand.

Windows have a major role in retaining heat. A window with double glazing can lose almost 10 times more heat as compared to the wall of same area (Cukierski, Rector, 2006). With the recent developments, various glazing types with different visible transmittance values are available and affordable. As a rule of thumb, effective Aperture (EA) or light admitting potential of a system can be calculated by multiplying the visible transmittance by the window-to-wall ratio for sizing (Ander, 2003). Figure2.22 shows that the glazing with a lower VT provides an opportunity to use a larger glazing surface.

However, the colour of the glazing and its effect on the interior light quality should be kept in mind, and it should be avoided to use very dark tinted glazing if the visual contact with the outside is important.

CLEAR

WWR: 0.30 HIGH VT: 0.88

TINTED

REFLECTIVE

WWR: 0.50 MEDIUM VT: 0.53

WWR: 0.70 MEDIUM VT: 0.38

Fig2.22 Three examples having the same EA of 0.26.

Source: After Robinson & Selkowitz, 2013

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REQUIRED NET = GLAZING AREA

2 x

AVERAGE DAYLIGHT FACTOR

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

x

VISIBLE TRANSMITTANCE

TOTAL AREA OF INTERIOR SURFACES x x

(

1 -

)

AREA WEIGHTED AVERAGE REFLACTANCE OF ALL INTERIOR SURFACES

VERTICAL ANGLE OF SKY VISIBLE FROM CENTER OF WINDOW

Fig2.23 Required net glazing area calculation. To estimate total window area, including frame and mullions, result can be multiplied by 1,25.

Source: Robinson & Selkowitz, 2013

Daylight and thermal comfort should be considered together while deciding the glazing parameters. Figure2.23 presents the basic calculation showing how to determine the required net glazing area. The average daylight factor can be accepted as 2% if average spaces are desired. In terms of thermal comfort, window to wall ratio (WWR) should be kept between 30% - 50% as a general rule (Robinson, Selkowitz, 2013). This ratio should be close to the lower limit, if higher performance is desired.

Due to its limited amount, the glazing should not be wasted for where it cannot be seen such as below the working plane. Furthermore, this may cause thermal discomfort in winter, and does not contribute much to the natural light level of the room.

A passive zone, an area twice the floor to ceiling height, is defined as a space which is next to the facade of a building and can benefit from the daylight, solar radiation and natural ventilation as stated by Baker and Steemers (2000) (Fig2.25). Therefore, the higher a window is, the more daylight penetrates into the office while extending the passive zone of the space (Fig2.24). Besides daylighting, the windows which are close to the ceiling also enables the warm air to be extracted. Although higher windows provide an advantage in terms of natural light, they exclude the possible visual contact with the outside. In this case, separate apertures for a better daylight penetration and view can be used while designing windows. This helps to eliminate the presence of glare for office spaces while getting natural daylight.

Fig2.24 Clerestory windows and lightshelves increase the potential of the daylit zone Source: Pohl, 2009

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

 

Fig2.25 A passive zone can be well-lit and naturally ventilated.

Source: After Lechner, 2010

Robinson and Selkowitz (2013) suggest using continuous strip windows to provide uniformity (Fig2.26). Therefore, providing a flexible interior layout and strip windows can be a good choice for open plan offices where the same quality of daylight is desired for everywhere, or if the tenants of the building are unknown. On the other hand, punched windows are applicable for smaller rooms such as private or shared offices since corners do not need to be well-lit in many cases.

Fig2.26 Continous windows should be selected when homogenously lit environments are desired. Punched windows should be paired, if they are used at working areas.

Source: Robinson & Selkowitz 2013

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2.4 ORIENTATION AND SHADING STRATEGY Shading elements offer a great opportunity to mainly differentiate buildings from one another and giving a sense of human scale. Unfortunately, the shading devices are considered as “ornaments” in many cases, and the necessary space for the related equipment is not allocated. It is possible to easily integrate these devices with architecture when the facade is designed as a “buffer space” instead of a single surface. This approach helps to place internal and external shading elements, design window openings, and apply self-shaded facade strategy (Fig2.27).

Fig2.27 Facades should be designed as a “buffer space”.

Source: Robinson & Selkowitz, 2013

Understanding shading devices behaviour with regards to different facades is quite important to use these components effectively. In most of the cases, a specific component may produce different results for daylight and thermal condition; hence, it is crucial to select which of them is more important for the building. Unlike fixed obstruction screens, well-designed light redistribution devices such as overhangs, lightshelves decrease the total solar insolation passing through the glazing, but let the diffuse light towards the inside of the building, therefore, they improve luminous efficacy (Baker, 2007). Additionally, the amount of daylight admitted show great variety depending on the material selection. For instance, translucent materials can be a good solution for office spaces where pitch-black darkness is not desired due to practical reasons.

Each facade requires a different strategy since their critical months and hours are different. According to Robinson and Selkowitz (2013), the peak solar radiation hours should be considered while determining the shading strategy. Therefore; September noon for the south, 10:00 am for the east, and 15:00 pm for the west facades should be studied. Interior shading devices are not effective as much as exterior ones in order to control unwanted solar gains. Hence, external shading should be preferred for spaces with high solar gains during the cooling period. Internal shadings such as blinds and curtains may be used to eliminate glare and provide privacy in offices (Fig2.28).

Fig2.28 Direct light on the working plane may create a glare issue.

Source: what-when-how.com, 2015

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

2.4.1 SOUTH FACADE In the northern hemisphere, the southern facade of a building gets the biggest amount of solar radiation energy throughout the year. Windows on this facade have high luminous levels but variable illumination during the day (Baker, Fanchiotti, Steemers, 1993). Although solar gains are higher during winter, the gains are slightly lower in summer because of the high sun angle. Due to the combined internal and solar gains, heavily glazed commercial buildings overheat in summer as a rule of thumb. As a result of his study for the Building Research Establishment (BRE), Louden (1968) stresses that a south facing office building with a window to floor area higher than 20% would likely to overheat. A key design strategy to prevent overheating is shading windows from direct sunlight with fixed or adjustable horizontal shading devices such as overhangs, external louvers and awnings (Fig2.29).

Fig2.29 Dynamic solar control system on southern facade of Soka Bau Office in Germany Source: After Pohl, 2009

The attractiveness of daylight has been acknowledged by many architects and designers as being able to create pleasant working environments. Therefore, they developed strategies to make daylight penetrate deeply through the use of a lightshelf, a light pipe or an atrium. A day-lighted zone, which is typically 1.5 to 2 times of distance from floor to window top, can be extended further by the use of a lightshelf while controlling the heat gain and the glare (Robinson, Selkowitz, 2013) (Fig2.30). Lightshelves are most effective for south facades and create a homogenous illumination pattern by shading the perimeter of said facade. It is agreed that tilting the lightshelf increases the effective depth, however, the existing literature fails to address the optimum tilting angle (Boubekri, 2014; Brown & DeKay, 2014; Ruck, 2000).

Therefore, the tilt angle should be determined through simulations.

 

Fig2.30 Increase in daylighted zone with lightshelf Source: After Lechner, 2010

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2.4.2 EAST & WEST FACADES East and west facing windows have almost equivalent influence on natural daylight, despite the fact that their effects can be seen at different times of the day. These windows provide medium luminous levels with a substantially differing illumination level throughout the day (Baker et al., 1993). High energy gains in summer and low ones in winter make these facades undesirable for spaces with high internal gain.

20% COVERAGE

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Fig2.31 Solar penetration can be controlled through vertical shading devices (Kantoor Bergopwaarts, Germany)(left). Translucent shading devices with different pattern and coverage ratio provide a high range of selection (right) Source: Colt Solar Shading Systems (left), viracon.com (right)

To use shading devices effectively, it is necessary to know the daily and monthly movement of the sun. Due to a low solar angle early in the morning and late afternoon, vertical shading devices such as adjustable fins and vertical panels are mainly used for east and west facades. Use of moveable shading devices, especially for the west facade, is suggested by Ho (1996) to allow winter sun to penetrate into the building (Fig2.31).

Vertical elements impair view, therefore, they are not preferred by occupants. After extensive studies conducted in office buildings, researchers stated that discomfort glare has been tolerated to a much greater degree than expected when an ample view and visual contact with exterior environment are provided (Chauvel et al., 1982 and Osterhaus, 2001). Furthermore, Ne’Eman and Hopkinson (1970) mention that a visual relation with the outside, and the information obtained as a result of this relation is more critical than the daylight or artificial light level of the room. Having the opportunity to provide an uninterrupted view, horizontal elements are also useful for east facades up to a certain extent (Robinson, Selkowitz, 2013). Buildings with regular occupancy schedule like offices and schools can benefit from horizontal shading devices since the building is not occupied early in the morning. In general, shading these facades is harder compared to the south ones, therefore, the building should be elongated along the east-west axis, if possible (Fig2.32).

Fig2.32 Buildings with longer envelope should facing south and north can be better protected from summer sun, while getting winter sun Source: After Climate Consultant 6.0

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2.4.3 NORTH FACADE The north facade in the northern hemisphere has the lowest luminous levels, yet illumination level is quite constant during the day (Baker et al., 1993). This facade is the least exposed one to radiant energy throughout the year. Hence, moderate openings should be preferred to minimize the heat loss due to the glazing especially if the internal gains are low.

Nevertheless, today’s office typology is characterized with high internal gains due to appliances, electricity lighting and occupant density. If this is the case, offices may suffer from overheating during summer and some offices may not need any direct solar gain even in the winter period (Fig2.33). Bradshaw (2006) stresses windows of internal gain dominated spaces should be facing north. It is not necessary to shade north facing windows, however, vertical fins can block early morning and late afternoon sun when the solar control is needed (Robinson, Selkowitz, 2013). If there is a limited budget, other facades should be shaded first.

Fig2.33 Sources of gains in a typical office environment Source: Robinson, Selkowitz 2013

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CONCLUSIONS 1. There is no dispute on the role of technological developments in changing working trends and office environments. In order to enhance occupant comfort, the correlation between the new office concepts and their impact on internal gains should be studied.

OR

CHANGE IN WORKING ENVIRONMENT

2. Literature research showed that buildings only reliant on mechanical ventilation systems suffer from high cooling consumption. Therefore, free-running period should be maximized. If buildings cannot be fully free-running due to climate conditions, mixedmode systems can be used.

FULLY AIR CONDITIONED

MIXED-MODE VENTILATION

3. New generation buildings are getting airtight with the advancements in construction sector. Since offices are high internal gain spaces, effective ventilation strategies such as cross ventilation and stack ventilation should be considered in the new designs.

1-SIDED VENTILATION

CROSS VENTILATION THROUGH ATRIUM

4. Low and high-tech energy production systems such as heat pumps, solar panels and geothermal wells can be used to reduce energy consumption effectively.

LOW & HIGH TECH ENERGY PRODUCTION SYSTEMS

Fig2.34 Outcomes of literature review

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5. Usage of excessive levels of glass should be avoided in order to provide thermal comfort in continental climates. Since glazing below the working plane does not contribute to the amount of useful daylight, windows with sill height can be used.

HIGHER WWR

LOWER WWR

6. Using dark colour of glazing deteriorates natural light quality of the space and increase lighting electricity consumption. Additionally, tinted glazing impairs occupant’s visual relation with outside.

According to Heschong (2003), visual contact with exterior has a direct relationship with workers’ performance. Hence, clear colour high-performance glazing should be preferred.

SINGLE GLAZING I TINTED

LOW-E DOUBLE GLAZING I CLEAR

7. Dynamic solar control systems have become a more relevant option to overcome the contradiction between allowing daylight, passive solar heating versus blocking unwanted solar gains since they adapt to seasonal and daily changes.

42o DYNAMIC SOLAR PROTECTION SYSTEM

8. Finally, thermal and visual challenges can still be handled through minimizing them during the design stage. Therefore, means of passive sustainability strategies should shape the design, prior to the costly technological systems.

Fig2.35 Outcomes of literature review

3. BUILT PRECEDENTS FORUM EAWAG CHRIESBACH ETRIUM BUILDING ESER GREEN BUILDING GSW HEADQUARTERS KFW WESTARKADE WMO HEADQUARTERS

ZURICH I SWITZERLAND COLOGNE I GERMANY ANKARA I TURKEY

BERLIN I GERMANY FRANKFURT I GERMANY GENEVA I SWITZERLAND

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INTRODUCTION The selection of the built precedents was based on their relevancy with the topic and innovative design strategies that address the environmental parameters, context and the climate. The first 3 buildings namely Eawag Forum Chriesbach, Etrium Building and Eser Green Building that belong to Generation 4.1 apply basic ventilation strategies via facade, and combines this with stack ventilation in many cases. On the other hand, high-rise Generation 4.2 buildings, GSW Headquarters, KfW Westarkade, and WMO Headquarters, use complex facade designs due to high wind velocity at upper floors.

Though many buildings are analysed and studied, these six buildings are chosen due to their path breaking strategies to accomplish good daylight, natural ventilation and energy use reduction. Having different scales from medium to high-rise office buildings, the precedents unite traditional passive strategies with high-tech design systems, and reflect the advantages and shortcomings of the present typologies.

Based on the learnings from the literature, the buildings are investigated by considering some criteria related with the context and their respond to the external conditions. These are the climate control, envelope design, energy and economic performance. These parameters are the main factors affecting the occupant comfort and the quality of the working environment as well as the energy usage. At the end of this chapter, built precedents are compared in terms of their sustainability strategies and performance.

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3.1 FORUM CHRIESBACH ZURICH, SWITZERLAND Official Name Eawag Forum Chriesbach Architect Bob Gysin + Partner BGP Architekten ETH SIA BSA Client Eawag Structural Engineer Henauer Gugler AG Sustainability Consultant Hansruedi Preisig + Ueli Kasser Roof & Facade Consultant Mebatech AG Completed 2005 Primary Use Office and Laboratorium Floor Above Ground 5 GFA 8533m2 Awards: Marketing + Architektur Award, 2008 AIT Office Application Award, 2008 Premio Internazionale Fassa Bortolo, 2008 Prime Property Award, 2008 Gebäudetechnik Award, 2008 Contractworld Award, 2008 (Shortlist) World Clean Energy Awards, 2007 (Nominee) Watt d’or, 2007 Velux Foundation Daylight Award, 2007 Swisspor Innovationspreis, 2006 Solarpreis, 2006

Fig3.1 Exterior view of Forum Chriesbach Building Source: Eawag, 2012

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VENTILATION TYPE

3.1 EAWAG FORUM CHRIESBACH Eawag, The Swiss Federal Institute of Aquatic Science and Technology, is a research center aiming to investigate and develop good water management.

By selecting the site close to Empa Scientific Center, with which the Eawag Institute works in collaboration, it is aimed to reduce the travel time and energy consumption. The building, completed in 2005, integrates vernacular design strategies with high-tech solutions. The 5-storey atrium improves the communication and acts as a “village square” where exhibitions and presentations are held. Adjacent spaces are arranged to create U-form around the atrium while letting daylight penetrate from south-west. The research held in this building requires small rooms with maximum four people (Fig3.9). Hence, the atrium is designed as a socializing place for the workers. These offices get natural light both from the atrium and exterior facades.

Mixed-mode for offices Natural ventilation for temporarily occupied areas NATURAL VENT. STRATEGY Wind driven cross ventilation Stack ventilation via atrium DESIGN STRATEGY Comfort and buffer zones FACADE Louver Panels: 2.8m in height

CLIMATE CONTROL The building has two zones; the mechanically ventilated comfort zone compromising offices, meeting room etc. and the buffer zone including the atrium and circulation areas (Fig3.10). The temperature in the buffer zone can fluctuate since this zone is not mechanically controlled. This innovative idea aims to reduce energy consumption by only heating permanently occupied spaces. The atrium is not cold during winter months due to the solar gains and well-insulated walls covering the three sides. Centrally controlled heating and cooling system follow different strategies for warm and cold periods. In winter, the warm air in the building enters to a heat exchanger to warm up incoming fresh air (Fig3.12). However, in summer, the air is expelled directly to the outside.

Forum Chriesbach uses solar and internal gains produced by people, equipment and lighting to heat the building. 468 mm thick exterior wall is composed of 300mm mineral wool insulation placed in between the

and 1m in depth ENERGY CONSUMPTION Primary energy consumption: 61 kWh/m2 a Heating energy consumption: 6 kWh/m2a (with renewables) Cooling energy consumption: 1.2 kWh/m2a (with renewables)

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Fig3.3 Monthly solar radiation for Zurich, Switzerland Source: Meteonorm

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prefabricated wood-frame panels. The extremely airtight wall has an extremely low u-value - 0.12 W/m2K - that helps to minimize the heat loss during the cold period (Wentz, 2007). During summer nights, motor-controlled windows open automatically and air is driven by stack effect to cool down the thermal mass (Fig3.13). This strategy is useful for airtight office buildings where high diurnal temperature difference is observed.

Frank, Güttinger, van Velsen (2007) monitored the internal conditions during 17 heat wave days in summer, 2006. During this period, the average indoor temperature was 24oC which is much lower than the outside temperature rising up to 36oC. The results show that EN15251 Category I standard is satisfied for 86% of the occupied hours. Moreover, EN15251 Category II Standards which complies with the Swiss standards were met for all the occupied hours. Another study shows that, during the first winter period in 2006, the building was occupied by average of 100 to 120 workers since scientists were attending conferences and giving lectures. Although this number is quite lower than the estimated number – 220 people -, the average temperature was measured between 20oC to 23oC (Wentz, 2007).

These promising results indicate that it is possible to minimize the heating loads by an airtight envelope while stack ventilation eliminates overheating problems in temperate climates. However, in many cases, these benefits are outweighed by budgetary pressures due to the high initial cost of extremely airtight facades.

BUILDING ENVELOPE AND ROOF The envelope of Forum Chriesbach has three major components; the wall, permanent scaffolding and shading devices. Manually controlled timber frame windows have triple glazing. Louvers, 1m in width, are comprised of screens with dot patterned voids placed between 24mm thick glass layers (Fig3.7). Office spaces do not need to be fully dim in general, thus using semi-transparent shading devices is an effective strategy as the winter solar gains are important. Vertical shading devices track the position of the sun to allow natural light to penetrate in winter but block it in summer. To control unnecessary adjustments due to each passing cloud, a hysteresis system is integrated into the control system.

The building roof is a multifunctional element which collects rainwater, generates electricity, helps ventilation and supports greenery. In summer, the shading devices on the atrium top closes automatically to minimize solar gains; and air between two glazing layers are cross-ventilated to prevent greenhouse effect. Vacuum tubes covering 50 m2 area on the roof accumulate solar energy. Additionally, the photovoltaic panels covering 459 m2 help to supply one third of the building’s power need (Wentz, 2007). Not being in a dense urban area, Forum Eawag uses the solar power advantage. However, this may not be possible for office buildings in the city centre.

ENERGY AND ECONOMIC PERFORMANCE According to values in the Detailed Energy Assessment of Eawag Forum Report (2009), actual heating load of the building was measured as 24 kWh/ m²BEIa in 2007. On the other hand, this value was only 6 kWh/m2a and 1.2kWh/m2a for heating and cooling when effect of renewables was included (Detailed Energy Assessment of Eawag Forum Report, 2009; www.sbd2050. org, 2011). Therefore, it is clear that low and high-tech systems have a great impact on reducing the energy consumption. These low values are mainly achieved by an airtight envelope working in harmony with the atrium. The building may be criticized for having large circulation spaces almost as big as the office areas.

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Fig3.5 Floor level D of Eawag Forum Chriesbach Source: Bob Gysin + Partner BGP, 2006

Fig3.7 Semi transparent vertical shading Source: Frei, 2006

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Fig3.6 Lateral section of Eawag Forum Chriesbach Source: Bob Gysin + Partner BGP, 2006

Fig3.8 Permanent scaffolding was not a part of the original design but added later for fire safety Source: Frei, 2006

Fig3.9 Working environment of the building Source: Detailed Energy Assessment of Eawag Forum Report, 2009

   

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Fig3.10 Zoning in the building Source: Bob Gysin + Partner BGP, 2006

Fig3.11 Primary energy consumption of the actual and planned buildings compared with Minergie standards Source: After Detailed Energy Assessment of Eawag Forum Report, 2009

Fig3.12 Day time mechanical ventilation via earth-to-air heat exchanger with buried pipes Source: Bob Gysin + Partner BGP, 2006

Fig3.13 Night time passive cooling by stack ventilation via the atrium to the roof outlets Source: Bob Gysin + Partner BGP, 2006

3.2 ETRIUM BUILDING COLOGNE, GERMANY Official Name Headquarters of Econcern Architect Benthem Crouwel Architects Client HIBA Grundbesitz GmbH & Co.KG Main Contractor HIBA Grundbesitz GmbH & Co Environmental Assessment Consultant G. Hoffmann Senior Auditor Energy Concept Ecofys Germany GmbH Completed 2008 Primary Use Office Floor Above Ground 3 GFA 4789m2 Awards: Seal of Quality in Gold, 2009

Fig3.14 Exterior view of Etrium Building Source: ecola-award.eu

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3.2 ETRIUM OFFICE BUILDING The Etrium Office Building, completed in 2008, is home to the Econcern Company. The building’s correspondence to the company’s objectives; sustainability and environmental conscience is considered from the beginning of the design stage. The Etrium, designed to accommodate 150 staff members, gets its name from the “energy efficient atrium” functioning as a used air zone. It was one of the first office buildings awarded for GOLD Seal

by German Sustainable Building Council. The building also has a BREEAM Excellent Certificate for the sustainable use of energy, water and well-being.

Mixed-mode NATURAL VENT. STRATEGY Wind driven ventilation Stack ventilation via atrium DESIGN STRATEGY Using atrium

CLIMATE CONTROL The main innovative feature of the building is applying a passive cooling system called Concrete Core Temperature Control (CCTC). Unlike the common system, in which fresh air is given directly to the working areas, the air flows through an aluminium tube exchanger system buried into the slab. The supply air warms up or cools down while cooling or heating the structure. The stored heating or cooling energy in the concrete dissipates slowly through radiation and convection. Suspended ceilings used to install lighting equipment easily in modern constructions cannot be used in this system. However, eliminating the suspended ceiling might be advantageous since the construction loads are reduced, and the clear height is increased for better daylight penetration.

“Concrete Core Temperature

The fresh air enters through the openable windows on the facade. The layout of the office requires additional piping system to apply cross ventilation and stack effect together. Moreover, this layout forces atrium-facing spaces to use mechanical ventilation. The high internal gains obtained from the equipment and people are used effectively to provide almost all the heat demand (Ilmonen, 2015). Additionally, the heat recovery unit works with 95% efficiency and help to decrease energy consumption.

ENERGY CONSUMPTION

Control” FACADE Recycled red glass facade Horizontal external louvers that are separated horizontally into two pieces

Primary energy consumption: 116 kWh/m2 a Heating energy consumption: 10 kWh/m2a Cooling energy consumption: 9 kWh/m2a

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Fig3.16 Monthly solar radiation for Cologne, Germany Source: Meteonorm

Fig3.17 Wind direction distribution in (%) Source: www.windfinder.com

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BUILDING ENVELOPES The external facade is made up from recycled red glass chips that give a unique appearance to the building (Fig3.20). The building shell is wellinsulated to minimize the heat loss. The exterior wall has an extremely low u value of 0.09 W/m2K - 0.17 W/m2K. (Bhar, 2016). This level of air-tightness may create high initial cost, as well as overheating problems if effective ventilation strategies are not considered.

In contrast to many conventional examples, the atrium has a relatively low height to width ratio which provides natural light to the adjacent spaces (Fig3.19). However, some spaces only rely on daylight coming from the atrium top due to the problematic layout (Fig3.18). Additionally, many rooms getting daylight from the facade cannot utilize the light coming from the atrium to decrease contrast. External horizontal louvers separated into two parts can be adjusted independently (Fig3.21). The light can reflect off the horizontal surface on the upper part of the louvers, although the lower part is slanted to block direct sun light and glare. Therefore, distinctively designed shading devices can solve a common problem without damaging the interior daylight level. The upper slats of the shading panels on the atrium top can be adjusted to block excessive solar radiation. Hence, heat gains from the fully glazed atrium can be kept under control. Internal curtains are available in the offices facing the atrium to dim the offices/meeting rooms when it is required (Fig3.22). Daylight and motion sensors in the working environment regulate the lighting level and prevent unnecessary electricity consumption.

ENERGY AND ECONOMIC PERFORMANCE The Etrium Office Building uses 116 kWh/m2 as a primary energy. With low annual heating and cooling energy consumption of 10 kWh/m2 and 9 kWh/ m2, the building complies with German Passive House standards, and it is the first large scale Passive House office building in Northrhine-Westphalia (Bhar, 2016). Surrounded by low rise buildings, Etrium produces 30000 kWh of electricity annually through the rooftop PV panels and small wind turbines.

This value is enough to provide electricity to cover the building’s energy demand when it works on a sustained basis (VÜgele, 2009).

Compared with the standard buildings, the monthly heating and electricity energy saving amount of this building is calculated as 0.7 Euro/m2 in 2015.

This value is expected to reach 1.1 Euro/m2 until 2025 (Bhar, 2016).

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Fig3.18 Floor plan of Etrium Building Source: www.baunetzwissen.de

Fig3.20 Red broken recycled glass as a facade material Source: Meisen, 2009

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Fig3.19 Section of Etrium Building Source: www.baunetzwissen.de

Fig3.21 Exterior horizontal louvers - upper and lower part can be controlled separately Source: Towards a New Architecture + Energy Part4, 2013

Fig3.22 Curtains and operable windows facing atrium Source: Objektiv Architecture Magazine, 2009

Fig3.23 Design concept of the building Source: www.detail.de, 2009

Fig3.24 Winter mode of HVAC system Source: Towards a New Architecture + Energy Part4, 2013

Fig3.25 Exhaust of air to atrium through the WCs Source: Towards a New Architecture + Energy Part4, 2013

Fig3.26 Summer mode of HVAC system Source: Towards a New Architecture + Energy Part4, 2013

3.3 ESER GREEN BUILDING ANKARA, TURKEY Official Name Headquarters of Eser Contracting and Industry Co. Inc. Architect Akun Mimarlık Muhendislik Musavirlik Ltd. Sti. Static Project Kemal Türkaslan Mühendislik Mim. Mus. Plan. Tic. Ltd. Sti. Energy Efficiency Consutancy EDSM Enerji Denetim Danısmanlik Servis ve Muh. Ltd. Sti. Leed Consultancy Altensis Insaat Enerji San. ve Tic. Ltd. Sti. Completed 2010 Primary Use Office Floor Above Ground 6 GFA 7500m2 Awards: LEED Platinum, 2011

Fig3.27 Exterior view of Forum Chriesbach building Source: www.eseryesilbina.com

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3.3 ESER GREEN BUILDING Eser Holding Company Building, completed in 2010, is the first building in Turkey certificated with LEED Platinum in 2011.

Mixed-mode NATURAL VENT. STRATEGY Ventilation via opening windows

CLIMATE CONTROL The Variable Refrigerant Flow (VRF) system has been used for heating and cooling. The heat obtained from ground source heat pumps are used to warm up the air and water during winter. The same system works in the opposite way for the cooling period (Fig3.36).

One sided ventilation is applied through the openable windows on the facade to control the interior temperature and provide fresh air. The building solves the bad air quality problem in office spaces with the new air handling unit design utilizing only the outside air. Thus, the amount of fresh air provided is 30% more than ASHRAE 62-1 standards (Altensis Energy Management, 2010). At night, when the electricity pricing is lower, the system produces and stores ice in order to cool down the building during the daytime (Fig3.35).

This problem could be significantly reduced with the use of a stack ventilation and night time cooling. However, the building mainly relies on engineering solutions instead of passive principles.

FACADE Fixed shading devices Tinted, reflective glazing ENERGY CONSUMPTION Heating energy consumption: 48 kWh/m2a Cooling energy consumption: 32 kWh/m2a

BUILDING ENVELOPE The building is elongated to north - south due to parcel conditions.

Therefore, benefit of passive solar gains are minimized in winter. In such a climate, this situation increases heating demand during the cold period while creating an overheating problem in summer. Additionally, elongation of the building makes it harder to provide consistent daylighting.

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Fig3.29 Monthly solar radiation for Ankara, Turkey Source: Meteonorm

Fig3.30 Wind direction distribution in (%) Source: www.windfinder.com

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80 mm, 120 mm and 60 mm thick thermal insulation panels were used for the walls, roof and floors respectively. The building has different envelope details regarding the orientation. Compared to the previous examples, Eser Green Building is not too airtight. Considering budgetary reasons and high summer daytime temperature in Ankara, using a more regular envelope is acceptable. However, this situation causes a penalty on heating consumption.

The low-e triple glazed windows covering 44% of the walls decrease heat loss through the facade significantly. However, a quite low SHGC value (0.46), which is in parallel with VT, deteriorates the daylight quality of the room and increases artificial lighting demand. Additionally, the literature indicates that the tinted glazing decreases the occupant’s connection to the outdoors which has a negative impact on workers’ performance. Due to the low VT value, fixed exterior shading devices are used (Fig3.32, Fig3.33).

ENERGY AND ECONOMIC PERFORMANCE In a typical building using natural gas boiler system for heating, and chiller system for cooling, the rational exergy management efficiency is less than 6%. This value increased up to 55% through implementing a balancing act.

Therefore, the carbon emission decreased by a factor of 2.1 (Cakmanus, Kunar, Toprak, Gulbeden, 2010).

The annual heating and cooling energy consumption is 48 kWh/m2 and 32 kWh/m2 respectively. The heating energy demand is 50% less than the maximum value estimated for the 3rd region in TS 825 regulation (Cakmanus et al., 2010). However, these values are still high compared to many good performing contemporary buildings analysed.

Although there are several attempts to create a sustainable design, the building mainly relies on innovative construction and mechanical systems without discovering the potential of climate and passive design strategies.

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Fig3.31 Plan of Eser Green Building Source: Ven ESCO Energy Management Consultant Archive

Fig3.32 West facade view Source: www.eseryesilbina.com

Fig3.33 East facade with vertical shading devices and north facade with no solar protection Source: www.eseryesilbina.com

Fig3.35 Summer (top) and winter (bottom) energy consumption Source: www.eseryesilbina.com

Fig3.34 Solar PV panels shading south facade windows Source: www.eseryesilbina.com

Fig3.36 Summer operation system Source: www.eseryesilbina.com

3.4 GSW HEADQUARTERS BERLIN, GERMANY Official Name GSW Hauptverwaltung Architect Sauerbruch Hutton Architekten Client Gemeinnutzige Siedlungs MEP Engineer Arup Sustainability Consultant Arup Completed 1999 Primary Use Office Height 81.5m Floor Above Ground 22 Structural Material Steel Tower GFA 48000m2 Awards: World Architecture Award shortlist for Europe, 2001 Architekturpreis Beton, Special Mention, 2001 Deutscher Architekturpreis, Special Mention, 2001 Mies van der Rohe Award Finalist, 2001 Deutscher Fassadenpreis, 2001 Berlin Architectural Award, 2000 RIBA Award, 2000 Stirling prize nomination, 2000 ar+d Award, High Commendation, 2000

Fig3.37 West facade view of GSW Headquarters Source: Scholl, 2009

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3.4 GSW HEADQUARTERS The expansion of GSW Headquarters Building, designed by Sauerbruch Hutton Architects, is one of the first low-energy high rise buildings (Generation 4.2). The building has become a landmark due to its colourful facade with hues of red and pink, and curvilinear shape when completed in 1999. The 22-storey high building uses stack effect, solar protection, cross ventilation and thermal storage as main passive design strategies (Fig3.37).

Mixed-mode Complementary-changeover NATURAL VENT. STRATEGY Single sided for celluar offices Cross ventilation for open offices Stack ventilation

CLIMATE CONTROL An adequate level of natural ventilation is quite important to provide occupant comfort and decrease cooling loads. Due to the strong winds hitting upper floors, GSW uses a common strategy; a double skin facade. During the peak hot and cold days, facades cannot be opened, therefore, the facade cavities act as a buffer zone. In the winter period, the fresh air is admitted through a raised floor system.

Various ventilation strategies are designed for the east and west facades depending on the wind direction. Mainly natural ventilation is used for the east facade whereas the spaces next to the west facade are ventilated with the help of the double-skin facade - buoyancy and stack effect. Differently from the previous examples, stack effect was used within the double facade, instead of an atrium. The building management system (BMS) controls airflow by simply opening and closing the dampers and make the occupants some suggestions about when to use the natural or mechanical ventilation through the green and red LED lights on the windows. This creates a compromise between freedom of user behaviour and technological means. The wing shaped membrane canopy avoids the risk of downstream air movement regardless of the wind direction (Fig3.43).

DESIGN STRATEGY Double-skin facade “Wing Roof” Slender form of the building DOUBLE-SKIN FACADE West: 1m depth East: 0.2m depth Hor. Continuity: Fully continuous Ver. Continuity: Fully continuous ENERGY CONSUMPTION Heating and cooling energy consumption: 150 kWh/m2a (estimated)

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Fig3.38 Monthly weather data for Berlin, Germany Source: Meteonorm 200

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Fig3.39 Monthly solar radiation for Berlin, Germany Source: Meteonorm

Fig3.40 Wind direction distribution in (%) Source: www.windfinder.com

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ENVELOPE Despite being structurally independent, the new building is connected to the existing tower which determines the ceiling height of 3.3 m (Fig3.42). However, the shallow building plan, 11 m in depth, assists working environment to be well-lit (Fig3.49). The sill height of 600 mm helps to improve thermal comfort during summer and does not inhibit the daylight utilization.

One remarkable feature of the building is the ventilation strategies varying according to the floor plan. Cellular offices can benefit from the 1-sided ventilation. On the other hand, the layout provides an opportunity of cross ventilation for open office (Fig3.46, Fig3.47). Therefore, open plan spaces with relatively higher internal gains can be cooled down effectively.

The west facade consists of double-pane windows on the inside which can be manually or automatically operated a 10 mm sealed single glazing on the outside. The glazing has an average U-value of 1.6 W/m2K. The space between these two layers are 0.9 m wide, and houses the aluminium shading devices that can be controlled by BMS or overridden by the users.

The entire facade can be shaded by the vertical louvers during the peak solar conditions. The shading elements with 18% perforation area create a bright environment inside the building, although the facade is fully shaded. This creates a similar effect with using translucent materials, and it is applicable to minimize the artificial lighting loads in an office space. The sliding and vertically pivoting shading panels give a flexibility for controlling the daylight and solar penetration (Fig3.44).

The luminaires adjacent to the windows are controlled by photocells inside the facade, however, can be overridden by the occupants. Therefore, artificial lighting loads can be reduced effectively. The rest of the artificial lighting system can be manually operated in groups.

ENERGY AND ECONOMIC IMPORTANCE GSW Headquarters considers passive strategies from the beginning of the design stage. The building form and elongation determined according to passive zone depth and prevailing wind direction are the clearest examples of bioclimatic design approach. The energy saved with passive and active strategies help to reduce the total energy consumption of the building up to 50%.

The annual energy consumption of GSW Headquarters for heating and cooling is approximately 150 kWh/m2 (Wood and Salib, 2013). However, these values are still quite high compared to the other precedents. Iyengar (2015) states that the building works in free-running mode for 70% of the year. This is quite remarkable for a high-rise building.

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Fig3.41 Typical floor plan of GSW Headquarters Source: Iyengar, 2015

Fig3.43 The wing shaped membrane canopy Source: www.archiexpo.com, 2016

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Fig3.42 Building section of GSW Headquarters Source: Iyengar, 2015

Fig3.44 Colorful folding perforated panels Source: filt3rs.net, 2012

Fig3.45 View from working environment Source: filt3rs.net, 2012

Fig3.46 Cross ventilation - open office Source: Kleiven, 2003

Fig3.47 One-sided ventilation - cellular rooms Source: Kleiven, 2003

Fig3.48 Thermal mass, summer Source: Sauerbruch Hutton Architects, 2000

Fig3.49 Sun penetration Source: Sauerbruch Hutton Architects, 2000

3.5 KFW WESTARKADE FRANKFURT, GERMANY

Official Name KfW Westarkade Offices Architect Sauerbruch Hutton Architekten Client KfW Bankengruppe Structural Engineer Werner Sobek Engineering & Design MEP Engineer Reuter Rührgartner GmbH; Zibell, Willner & Partner Completed 2010 Function Office Height 56m Floor Above Ground 14 Tower GFA 22300m2 Awards: CTBUH 2011 Best Tall Building Worldwide Green Building Frankfurt award, 2009

Fig3.50 Exterior view of KfW Westarkade Source: Lowus, 2012

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3.5 KFW WESTARKADE The KfW Westarkade building, completed in 2010, is one the first tall buildings that consume less than 100 kWh/m2 energy per year. This 14-storey high building provides an office area for approximately 700 people. The polychromatic facade consists of narrow natural ventilation flaps, and the colours are addressing the spaces around the building. The main sustainability strategy for this building is to use the prevailing wind for ventilating the interior spaces naturally by means of a double skin wind-pressurized facade.

Besides, the geothermal energy and thermally activated slabs are used to decrease the energy consumption.

Mixed-mode Complementary-changeover NATURAL VENT. STRATEGY Wind driven cross ventilation Stack ventilation via core DESIGN STRATEGY Double-skin facade

CLIMATE CONTROL

“Pressure Ring”

The saw-tooth facade creates a unique appeal while separating the fixed windows from the ventilation panels (Fig3.56). Therefore, the facade view is not disrupted due to the ventilation panels (Fig3.58). The double skin facade forms a “pressure ring”. Unlike a traditional double facade using the stack effect for ventilation, the cavity of the pressure ring is ventilated through the suction and wind pressure on the leeward side of the building. Therefore, KFW takes micro climatic conditions into consideration and combines them with the means of technology to overcome the ventilation problems in a high rise office. Being controlled by BMS, the flap panels on the external facade provide consistent positive pressure – slightly higher than the inside- within the ring. The inner facade has operable windows, allowing the building to be naturally ventilated.

A typical problem of naturally ventilated offices is the excessive amount of cross ventilation due to the difference in pressure between the windward and leeward areas. The air speed within the ring is regulated in order not to exceed 6 m/s, therefore, the natural ventilation is available for eight months a year without creating any drafts or heat loss (Wood, Salib, 2013) (Fig3.59).

Aerodynamic external form DOUBLE-SKIN FACADE 0.7m depth Hor. Continuity: Fully continuous Vert. Continuity: 3.7m ENERGY CONSUMPTION Primary energy consumption: 82 kWh/m2a Heating energy consumption: 44 kWh/m2a Cooling energy consumption: 22 kWh/m2a ANNUAL

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Fig3.51 Monthly weather data for Frankfurt, Germany Source: Meteonorm 200

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Fig3.52 Monthly solar radiation for Frankfurt, Germany Source: Meteonorm

Fig3.53 Wind direction distribution in (%) Source: www.windfinder.com

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Functioning as a thermal solar collector, the double-layered facade tempers the air in the ring, therefore, conserves the heating energy. During the warm periods, the outer facade can be opened to prevent overheating (Fig3.61).

The pressure ring strategy minimizes direct dependence on the outside conditions by enabling natural ventilation in the building. The air admitted from the facade is driven to the negative pressure areas such as cores and corridors, and exhausted through the shafts which ventilate the roof. If the temperature within the cavity falls below 10oC or rises above 25oC, the air conditioning system is activated. In this situation, the fresh air taken from the outside travels through a buried duct, then it is pre-tempered in a 30-meter long geothermal duct to maximize the efficiency of the mechanical ventilation.

During the cold periods, the warm exhaust air is brought to the HVAC center through a by-pass flap for heat-recovery.

The building runs under a complementary-concurrent system where natural ventilation is allowed although the mechanical air conditioning is also running (Wood, Salib, 2013). However, the users are advised to open or close their windows through the LED lights as in the previous example.

ENVELOPE The cavity, 0.7 m in depth, is partitioned at each floor for the fire safety.

A weather-station mounted onto the roof monitors the outdoor conditions and controls BMS to open or close the ventilation flaps. These colourful glass panels alternate between an acoustically insulated fixed panel and an operable panel that can open up to 90o to provide fresh air into the double facade system. The inner facade consists of argon-filled low-e operable and fixed window units.

The horizontal shading devices placed in between facades help to control the solar insolation and risk of glare. Additionally, an integrated natural light redirection system provides good interior daylight levels although the facades are shaded.

ENERGY AND ECONOMIC PERFORMANCE KfW Headquarters overcomes the common problems observed in naturally ventilated high rise offices by designing a floor plate as an aerodynamic wing and taking the double facade strategy a step further. Using different strategies for the pressure ring in warm and cold periods, the building can be naturally ventilated for 60% of the working hours (Wood, Salib, 2011).

The building was estimated to consume 50 kWh/m2 annually for heating and cooling (Wood, Salib, 2011). However, the real situation is higher than expected. According to the measurements, the building uses 44 kWh/m2 for heating and 22 kWh/m2 for cooling annually (www.sbd2050.org, 2011).

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Fig3.54 Typical floor plan of KfW Westarkade Source: www.archdaily.com, 2013

Fig3.56 Saw-tooth facade of KfW Westarkade Source: www.archiexpo.com, 2016

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Fig3.55 Building section of KfW Westarkade Source: www.archdaily.com, 2013

Fig3.57 Colorful ventilation flaps Source: Lowus, 2012

Fig3.58 View from interior Source: Lowus, 2012

leeward side negative pressure

windward side positive pressure

main wind direction south/west

Fig3.59 Creation of an equalised pressure ring within the cavity of the double facade Source: Sauerbruch Hutton Architects, 2010

Fig3.60 Wind-pressure in windward and leeward sides Source: Sauerbruch Hutton Architects, 2010

Fig3.61 Direct ventilation of the double facade in summer Source: Sauerbruch Hutton Architects, 2010

Fig3.62 Natural ventilation within the office space, central air exhaust Source: Sauerbruch Hutton Architects, 2010

3.6 WMO HEADQUARTERS GENEVA, SWITZERLAND

Official Name Organisation Météorologique Mondiale Architect Atelier d’Architecture Rino Brodbeck and Jacques Roulet Client WMO & Swiss Confederation Structural Engineer M. Buffo et M. Paquet Energy Engineering ERTE S.A. Environmental Impact Assessment ZS Trafitec SA Facade Consultant Emmer Pfenninger Partner AG Completed 1999 Primary Use Office Floor Above Ground 9 GFA 39268m2

Fig3.63 Exterior view of WMO Building Source: earthzine.org, 2013

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3.6 WMO HEADQUARTERS The “Chic Planète” project was designed by Brodbeck and Roulet for the WMO Headquarters Building competition in 1993. The eight-storey high building has a west-east alignment due to the geographical constraints of the site (Fig3.72). While the cold wind coming from mountains hits the north facade, the south facade is exposed to the direct high solar radiation.

To decrease energy consumption cost, the building uses its own internal generator during the daily peak – expensive- periods.

WMO Headquarters uses low and high-tech sustainability systems such as; dynamic facades, geothermal well, comfort and night ventilation strategies.

Besides that, various facade strategies depending on the orientation and prevailing wind direction show the building’s commitment to the bioclimatic design.

Mixed-mode NATURAL VENT. STRATEGY Stack ventilation via core DESIGN STRATEGY Double-skin facade Slender form of the building DOUBLE-SKIN FACADE North: Fixed external facade South: Openable external facade

CLIMATE CONTROL

Hor. Continuity: Fully continuous

The double facade buffers the building from the extreme conditions of the mountain weather. During winter, the outer windows on the south and north facades are kept close to decrease heat loss, however, only southern facade panels are opened during summer to prevent overheating (Fig3.70).

Therefore, energy consumption could be minimized. Operable internal windows let occupants to control each office for individual comfort standards.

The cold air sucked from outside travels through the largest geothermal well of Switzerland and gets warmer as it rises. This well-known strategy keeps internal temperature constant, between 20–26oC. The twin flow ventilation system connected to the vertical structure eliminates the need of a suspended ceiling, therefore the daylight penetration is maximized and the construction cost is reduced.

Ver. Continuity: a floor-high ENERGY CONSUMPTION Heating and cooling energy consumption: less than 110 kWh/m2a

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Fig3.64 Monthly weather data for Geneva, Switzerland Source: Meteonorm 200

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Fig3.65 Monthly solar radiation for Geneva, Switzerland Source: Meteonorm

Fig3.66 Wind direction distribution in (%) Source: www.windfinder.com

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The fresh air is sucked from the basement during the coolest hours of the day - before dawn. The emergency staircase turns into a huge chimney while air passes through the core. This innovative strategy can be used in many buildings to minimize the requirement of a piping system. The rising air reaches to the office areas through the ventilators. Hence, the air temperature is decreased for 3-4oC and the refreshed air is provided to the users every morning before the work begins.

ENVELOPE Aluminium, steel and glass are mainly used for transparency and an elegant appearance. The reinforced glazing helps to increase shaded area up to 40%. The specially treated operable panels on the southern facade allows only 17% of solar radiation to penetrate (Fig3.69).

WMO is using glass walls for the offices. This easy solution combined with translucent shading devices lets daylight reach to the walls of the core (Fig3.71). The movement sensors connected to the luminaires help to provide well-illuminated interior for a lower cost. Energy efficient bulbs are used to compensate for the high initial cost of the sensors.

ENERGY AND ECONOMIC PERFORMANCE An ordinary building in Switzerland uses 220 kWh/m2 per year which is limited to 110 kWh/m2 in accordance with the new regulations of the Swiss Federal Government. However, the WMO Headquarters consumes less than this amount (Building for the twenty-first century, 1999).

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Fig3.69 Horizontal shading devices Source: architectes.ch, 2015

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Fig3.70 South facade of WMO Building with adjustable panels Source: www.myswitzerland.com, 2016

Fig3.72 Building sitting diagram showing how ellipse shape appeared Source: Brodbeck&Roulet, 2008

Fig3.71 A view from interior Source: solar-club.web.cern.ch, 2004

Fig3.73 Fresh air (green) is stored under the building to be drawn on as needed for cooling (blue). Used air is drawn out from every space (orange). In cold weather, heated air is filtered and circulated through the same trunks and vents.

Source: WMO, 1999

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Table3.1 Comparison of the selected built precedents

GENERATION 4.1

1. EAWAG FORUM CHRIESBACH

2. ETRIUM OFFICE BUILDING

3. ESER BUILDING

A new aquatic research center committed to water management and sustainability principles

Energy efficient building design for Econcern Company

The first building in Turkey certificated with LEED Platinum

Zurich, Switzerland

Cologne, Germany

Ankara, Turkey

2005

2008

2010

Creating buffer zone and mechanically ventilated comfort zone + using internal gains as a heating source

Using atrium as an exhaust zone + using existing energy sources (internal gains, solar radiation etc.)

Using renewable sources + designing facades regarding orientation

ANNUAL HEATING AND COOLING ENERGY CONSUMPTION

2.7kWh/m2 for heating, 1.2kWh/m2 for cooling (including renewables)

10kWh/m2 for heating, 9kWh/m2 for cooling

48kWh/m2 for heating, 32kWh/m2 for cooling

VENTILATION SYSTEM

Mixed mode for offices, natural ventilation for temporarily occupied areas

Mixed mode

Mixed mode

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LOCATION

COMPLETED

FACADE I SOLAR CONTROL

VENTILATION

GENERAL

MAIN SUSTAINABILITY STRATEGY

NATURAL VENTILATION STRATEGY

Wind driven cross ventilation + stack ventilation via atrium

Wind driven ventilation + stack ventilation via atrium

Single sided ventilation

WINTER STRATEGY

Using heat exchanger + keeping atrium top closed

Using heat recovery + keeping atrium top closed

Using ground source heat pumps + Variable Refrigerant Flow System

SUMMER STRATEGY

Opening facade and windows at atrium top to dispel heat

Opening the atrium top + cooling the fresh air with ground water + Concrete Core Temperature Control

Opening window + Variable Refrigerant Flow System

Exterior corridor/ permanent scaffolding as a buffer zone

Using recycled glass as a facade material

Using renewable sources for the facade material

BMS controlled glass shading panes having screen with dot patterned voids in between

External horizontal louver which is separated into two and can be adjusted independently

Slanted overhang at south, vertical fixed shading at east and west

FACADE

PROVISION FOR SOLAR CONTROL

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GENERATION 4.2

4. GSW HEADQUARTERS

5. KFW WESTERKADE

6. WMO HEADQUARTERS

Extension and a renovation of a headquarters building

A new high-rise headquarters building allowing natural ventilation

“Chic Planète” proposal for WMO Headquarters competition

Berlin, Germany

Frankfurt, Germany

Geneva, Switzerland

1999

2010

1999

MAIN SUSTAINABILITY STRATEGY

Double facade and single facade usage for windward and leeward facades respectively

Development of the “pressure ring” facade to allow natural ventilation while blocking excessive amount of air flow

Double facade acting as a protective, insulating envelope and a ventilation system + “Canadian well” system

ANNUAL HEATING AND COOLING ENERGY CONSUMPTION

150kWh/m2 (estimated)

44kWh/m2 for heating, 22kWh/m2 for cooling

less than 110kWh/m2

VENTILATION SYSTEM

Mixed mode

Mixed mode

Mixed mode

Single sided ventilation for cellular offices, cross ventilation for open offices + stack ventilation

Wind driven cross ventilation + stack ventilation via core of the building

Single sided ventilation + stack ventilation via core of the building

WINTER STRATEGY

Raised floor system for fresh air admission+ usage of warm air in the cavity with heat recovery system

Using BMS controlled flaps for fresh air and solar heating+ geothermal energy

Keeping outer windows of the north and south facade closed

SUMMER STRATEGY

Ventilation via stack effect at west and natural ventilation at east facade + radiant cooling strategy

Opening outer facade to prevent overheating

Opening outer windows of the south facade to prevent overheating

Double skin facade at west, triple glazing at east

Double skin sawtooth facade “pressure ring”

Double skin facade

18% perforated vertical shading devices

Internal horizontal shading devices

Treated operable panels allowing only 17% of solar radiation at southern façade

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LOCATION

GENERAL

COMPLETED

FACADE I SOLAR CONTROL

VENTILATION

NATURAL VENTILATION STRATEGY

FACADE

PROVISION FOR SOLAR CONTROL

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CONCLUSIONS The built precedents are analyzed and compared according to various parameters including the environmental design strategies and energy consumption (Table3.1). It is clear that Generation 4 buildings are shaped by traditional passive principles and high-tech systems are used to minimize the environmental impact. Generation 4.1 and 4.2 buildings differ mainly in terms of facade designs. The first 3 examples that belong to Generation 4.1 have quite low u-values in the facade to minimize the heat loss, while the others from Generation 4.2 use double facades to control the wind speed and minimize the loads on the construction. Almost all built precedents have introduced stack effect to maximize the efficacy of ventilation. This can be done via an atrium as in Eawag Forum Chriesbach and Etrium Building, between double skin facade or via the building core. Due to extremely airtight facade, Generation 4.1 buildings use stack and/or cross ventilation to cool down the building. On the other hand, high rise buildings use the buffer space in between facades to control the speed of the air introduced to the working environment, and as a solar chimney during the cold periods. KfW Westerkade creates a pressure ring between the facades taking the double skin technology one step further.

Although different ventilation strategies are used, buildings from both generations (Eawag Forum Chriesbach, GSW and WMO Headquarters) use translucent shading devices that provide sufficient shading while maximizing the daylight penetration. Additionally, specially designed horizontal shading devices are divided into two to control daylight efficiently in the Etrium Building.

Eawag Forum Chriesbach shows a big potential since the building plan adopts a “layer system� that provides a great flexibility in plan dimensions.

Therefore, the layout of this building was used as the primary example for further studies.

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4. CONTEXT & CLIMATE CONTEXT TEMPERATURE & COMFORT BAND SOLAR RADIATION WIND DEFINING HYPOTHETICAL CONTEXT

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4.1 CONTEXT Ankara is located in the central Anatolia region, at the latitude of 39o56’ North and longitude of 32o52’ East. It is 938 m above the sea level and the second largest city with a population of 5.150.000 after Istanbul. Being the capital city of Turkey, Ankara accommodates the offices of various ministries.

Additionally, many firms have started to invest in this city during the last decades. TurkStat (2016) data indicates that, in 2015, 467 offices got their construction permits in Ankara. Unfortunately, the city planning regulations could not follow the rapid growth in the city, therefore, the issue of unplanned urban context appeared.

32o 52'E

The centre of business and trade has shifted from historic Kizilay and Ulus to around the newly constructed 8-lane roads along with the motto of “Road is Civilization”. This situation has created a 3-layered system that lies parallel to the road depending to the affordability of the land (Fig4.1). The government offices and high rise commercial buildings are mostly located on the expensive lands around the main roads. These fully-glazed prototypical high-rise buildings are used to show prestige and wealth. The second layer is occupied by ministries and mid-rise office blocks. Unfortunately, the buildings in this layer imitate the high rise buildings, and thus they suffer from high WWR. The last layer consists of residential blocks which differ in height. The width of these layers shows variety according to the width of secondary roads, in many cases. This dissertation mainly focuses on “the second layer” buildings which have the most potential to be “Generation 4.2” building.

39o 56'N

1ST ZONE

2ND ZONE

ANKARA

3RD ZONE

Fig4.1 Ankara’s geographical location (top left), top view image to identify zones (bottom left) and photograph showing first and second zones Source: Google Earth (bottom left), www.klndigital.com (right)

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4.2 TEMPERATURE & COMFORT BAND The weather data was generated using Meteonorm 7 software by interpolating radiation and temperature data from nearby weather stations.

Ankara has a hot summer continental climate according to Köppen climate classification. Because of its inland location, the winter months are quite cold and snowy, and the summer months are hot and dry. Although the winters are cold, this period is shorter than the warm period. The diurnal chart illustrates that the maximum temperature in summer reaches around 33°C, while the minimum temperature can go as low as -20°C during winter (Fig4.2). Providing the opportunity for night time cooling, Ankara has a high diurnal temperature difference during summer.

  





  





















 

 

































Fig4.2 Monthly diurnal averages for Ankara Source: Meteonorm 7



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It is important to consider adaptive design strategies to mitigate the effects of climate change. The climate scenario for 2050 estimates that the temperature is going to increase approximately by 2°C in comparison with the present scenario. Thus, future overheating problems should be considered during the design stage while coping with low temperatures in winter.

The adaptive thermal comfort band was calculated using the EN 15251 – Building Category II for both present and future scenarios (Table2.1, Table 2.2). A comfort band width of 6oC was considered to define the limits of comfort. Although the cold period range remains the same, the upper limit of comfort was raised from 29.7oC to 30.3oC in the warm period.

Table4.1 Monthly mean temperatures and adaptive comfort band according to EN15251 - Category II Source: Meteonorm 7      



  



 



  



























 









































































 

 

Table4.2 Monthly mean temperatures and new adaptive comfort band according to 2050 A2 Scenario Source: Meteonorm 7 IO

























 









































































 

82

ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

4.3 SOLAR RADIATION Variations in diffuse and global solar radiation levels can be observed in the graph when compared to 2050 scenario (Fig4.3). The mean irradiance of global radiation considerably fluctuates between January (53 W/m2) and August (209 W/m2), reaching up to a 75% decrease during the cold period.

Having an almost equal amount of direct and diffused radiation during the winter months, the warm periods show a greater difference in both scenarios. The direct solar radiation during June, July and August is almost 2 times higher than the diffuse insolation and this reveals a necessity to apply a shading strategy for the summer period.

Figure4.4 shows that south facade receives 38% less solar radiation than east and west facades in warm period. On the other hand, the situation is the opposite for winter. Due to low winter temperatures, as mentioned in the previous part, north oriented offices may require additional heating despite the high internal gains.

Having more overcast skies than the sunny days, the annual average cloud coverage is 4.5 octas for the current scenario.

   





    

 

























Fig4.3 Monthly solar radiation for current and future climate Source: Meteonorm 7   

 

  













  

































 



Fig4.4 Monthly mean global radiation on different planes Source: Meteonorm 7

Fig4.5 Sun path diagram for summer and winter equinox for Ankara shows high sun angle (73O) towards south during summer equinox and low (27O) during the winter equinox Source: Ladybug + Honeybee

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

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4.4 WIND During summer, the prevailing wind comes from north-west with a relatively high average speed of 3.3 m/s and provides an opportunity for natural ventilation (Fig4.7). Along the year, the wind speed in warm period is higher than the winter. Additionally, wind velocity ranges between day and night increase in summer (Fig4.6).

ANNUAL



JUN







 





 







DEC





  



 

























AVERAGE WIND SPEED: 2.3 M/S  

Fig4.6 Monthly average wind speeds in general and for occupied period I 09:00 - 18:00 Source: Meteonorm 7

M/S

0

1.4

2.8

4.2

5.6

Fig4.7 Wind roses for Ankara Source: Ladybug + Honeybee

7



84

ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

4.5 DEFINING HYPOTHETICAL CONTEXT Surrounding buildings have a huge impact on solar gains as well as the amount of daylight admitted to the space. Therefore, 4 possible urban canyon scenarios were defined according to Turkish Regulations (Fig4.9). Considering budgetary reasons, buildings were assumed to have maximum in height. It is found that all cases have 45o obstruction angle approximately. The second case was selected to be studied in detail. As seen in the Figure4.10, the selected scenario was located into a more realistic context that reflects the current situation of Ankara.

An analytic work was held to investigate the effect of the urban context for the different floors. Besides the selected case, an extreme scenario with higher obstruction angle was studied since many buildings in Ankara get special permission to increase in height (Fig4.11).

URBAN CANYON: 0.8 height to width ratio

URBAN CANYON: 0.9 height to width ratio    





  



URBAN CANYON: 1 height to width ratio

Fig4.8 Top view of the hypothetical context





URBAN CANYON: 1.1 height to width ratio

 



 







Fig4.9 Possible urban canyon scenarios according to regulations

3RD ZONE VARIATION IN HEIGHT FUNCTION: RESIDENTIAL

2ND ZONE LOW & MIDRISE BUILDINGS FUNCTION: COMMERCIAL

1ST ZONE HIGH RISE BUILDINGS & THEIR BASE BUILDINGS FUNCTION: COMMERCIAL

Fig4.10 Hypothetical context and studied building

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The Figure4.12 shows that due to the high position of the summer sun, the change in the opposing building height did not create a significant difference in the solar insolation level falling on south facade. However, the amount of solar radiation received in winter reduced by 61% and 36% for top and ground floors, respectively. Since passive solar gains during winter are crucial, south facade should not be obstructed, if possible. Being exposed to the low angle sun throughout the year, the east and west facades showed similar trends to the change in obstruction angle in both seasons. Additionally, the reduction range between floors were less significant than the south facade. The change in obstruction angle was insignificant for the north facade since it receives low solar radiation throughout the year.

The width of the opposing building and nearby streets also have an influence on the solar radiation pattern falling to a facade, especially when sun is at low altitude (Fig4.13, Fig4.14). Therefore, the context should be taken into account to get more realistic results during daylight and thermal studies.

2nd floor of the building in Context 1 was chosen for further analytic work.

CONTEXT I OBSTRUCTION ANGLE: 42O

CONTEXT 2 OBSTRUCTION ANGLE: 55O

42o

55o

Fig4.11 Contexts used for solar radiation analysis. Context 1 is created according to maximum height limits in current regulations, Context 2 defines a scenario as the neighborhood building height is increased with a special permission

 





  





  

 

  

 







 







 

 

 

 

 

















 



 

       

 









  



Fig4.12 Average solar radiation falling on different floors for summer and winter weeks Source: Ladybug + Honeybee



        



       



    

     





    

    

86

ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

CONTEXT I JUNE, 1ST I AUGUST, 31ST SOUTH 168 KWH/M2

S

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

KWH/M2

EAST 196 KWH/M2

E

0

20

WEST 189 KWH/M2

40

60

80

W

100

120

140

160

NORTH 71 KWH/M2

180

>200

N

DECEMBER, 1ST I FEBRUARY 29TH SOUTH 149 KWH/M2

EAST 63 KWH/M2

WEST 69 KWH/M2

NORTH 21 KWH/M2

Fig4.13 Average solar radiation falling on the facade during summer and winter periods Source: Ladybug + Honeybee KWH/M2

CONTEXT 2 JUNE, 1ST I AUGUST 31ST SOUTH 143 KWH/M2

S

EAST 103 KWH/M2

E

0

20

WEST 101 KWH/M2

40

W

60

80

100

120

140

NORTH 53 KWH/M2

DECEMBER, 1ST I FEBRUARY, 29TH SOUTH 62 KWH/M2

EAST 42 KWH/M2

WEST 46 KWH/M2

Fig4.14 Average solar radiation falling on the facade during summer and winter periods Source: Ladybug + Honeybee

NORTH 13 KWH/M2

160

180

N

>200

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

CONCLUSIONS SOLAR CONTROL 1. Solar control for south, east and west facades must be provided during the whole year. The shading strategy for north facade can be determined after holding daylight and thermal studies.

2. High summer sun angles make south facade ideal for allowing optimal solar control. On the other hand, east and west facades are being problematic due to low summer sun angles. Therefore, buildings with high internal gains should be elongated to east – west orientation to minimize the cooling energy consumption.

3. As the annual average sky coverage is 4.5 octas, shading devices must be studied both for sunny and overcast skies. Moreover, dynamic solar protection systems can be taken into account since they respond better to the changes in the sky and allow better control of solar radiation and glare.

4. Despite all the factors, sunny spaces are necessary to enhance the space quality. However, temporarily occupied areas with low internal gains such as; a 3-sided atrium or a cafeteria space could be considered for this.

DAY-TIME & NIGHT-TIME VENTILATION 1. Daytime ventilation during mild and warm period is necessary to provide occupant comfort. Besides climate study, literature research also revealed that ventilation implemented for the limited period of a year could reduce the cooling consumption significantly.

2. Diurnal temperature range reaching up to 15oC in warm period suggest the potential of night cooling. The necessity of night-time ventilation would increase, since summer day-time temperatures could exceed the comfort levels in the future. Therefore, this ventilation strategy should be integrated into buildings to prevent future overheating problems.

3. In case of high thermal mass usage, night time cooling helps to cool down the space in summer nights.

4. Security issues should be considered during the design stage.

CONTEXT 1. As a part of the sustainable design approach in an urban area, the effects of contextual factors such as, neighbourhood buildings, vegetation, fences etc. should be taken into account. Otherwise, contradictions between expected and real-life cases occur.

2. Solar protection strategies should be determined in floor level since solar radiation falling on a vertical surface shows great variety when context is considered.

ECE DURMAZ

87

5. ANALYTIC WORK DAYLIGHT ANALYSIS: PART I DAYLIGHT ANALYSIS: PART 2 THERMAL ANALYSIS

90

ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

ECE DURMAZ

91

5.1 DAYLIGHT ANALYSIS PART I

DEFINING THE SHOE-BOX: SELECTING SHADING DEVICE The first step to carry out an analytic work for the facade design is to define a shoebox and select the shading strategy for each orientation according to the direct solar radiation blockage and daylight levels of the office environment.

Regarding the findings in the literature review, the WWR was kept constant as 50% for this study and the glazing area was not wasted below the working plane. The simulation parameters are indicated below (Table5.1).

The design process involved testing different shading strategies, materials and sky conditions, depicted in the columns on the left and right side of the pages, to assess their efficacy to provide comfortable daylight levels in computerized offices. The daylight analysis was conducted using Ladybug + Honeybee which is a user interface for Radiance Engine. The measurement plane was set to 80 cm above floor level, in order to study the daylight levels on the working. The comfort range was accepted as 300 – 2000 lux (CIBSE Guide A, 2016). The hours studied for each orientation were September 21st, 12:00 for the south, 10:00 for the east, 14:00 for the west and June 21st, 17:00 for the north facade. This criterion was based on the most problematic hours of the facades.

Each shading device was indicated with a different colour. The selected cases were marked with a “tick symbol” to be used for further analysis.

Additionally, the studied orientations were marked with various colours on the left part of the page.

Table5.1 Daylight simulation parameters

GENERAL

TRANSMITTANCE

Area

135m2

Clear height

3.2m

Glazing

RADIANCE PARAMETERS 0.65

-ab

4

-ad

256

-as

128

WWR

50%

REFLECTANCE

Occupancy hours

09:00 - 18:00

Wall

0.65

-ar

128

Orientation

Varies

Floor

0.45

-aa

0.25

Shading

Varies

Ceiling

0.85

Context

No

Furniture

0.60





 

  Fig5.1 Configuration of shoe-box model

92

ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

5.1.1 SOUTH FACADE

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

5.1.1 SOUTH

OVERCAST I SEP 21 I 12:00 CASE 1: OVERHANG MEAN ILLUMINANCE: 510 LUX

54o

For the south orientation, the overhangs with translucent and solid shading devices were compared. 1.5m deep balcony had a 54o vertical shading angle to block direct sun coming in the expected overheating hours (Fig5.5). Studied solar control devices were adjusted differently under overcast and sunny sky conditions. It was found that both translucent and solid blades perform similarly while it is overcast, and that the daylight level for this orientation gets lower compared to Case 1 (Fig5.3).

Figure5.6 shows that having an overhang alone was not enough to protect the office environment from excessive amount of daylight. Therefore, additional shading devices are necessary for this orientation. The illuminance levels were above the minimum standard- for the translucent blades throughout the room (Fig5.6 Case2). On the other hand, the solid blades maintained 300 lux only for 1.5 m in depth. Since open offices do not require fully dim environments for practical reasons, translucent horizontal blades were selected for this facade.

OVERCAST 21 SEPTEMBER I 12:00

CASE 2: TRANSLUCENT BLADES MID - PART 30o TILTED W: 55CM I VT: 0.15 MEAN ILLUMINANCE: 332 LUX

      









 





    Fig5.3 Section of illuminance for different shading strategies under the overcast sky Source: Ladybug + Honeybee CASE 3: HORIZONTAL BLADES MID - PART 30o TILTED W: 55CM I R: 0.85 MEAN ILLUMINANCE: 313 LUX

Fig5.4 Illuminance of Case 2: Translucent Blades in overcast weather Source: Ladybug + Honeybee Fig5.2 Studied shading strategies under the overcast sky Source: Ladybug + Honeybee

N LUX 0

150

300

450

600

750

900

1050

1200

1350

>1500

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

ECE DURMAZ

93

90 80 70

54o

60

SUNNY I SEP 21 I 12:00

50

CASE 1: OVERHANG MEAN ILLUMINANCE: 1630 LUX

40 30 20 10 120

90 East

60

30

0 South

30

60

0 120

90 West

OVERHANG I BALCONY VSA: 54o

54o

Fig5.5 Sun shading chart used to determine vertical shadow angle Source: Climate Consultant

SUNNY 21 SEPTEMBER I 12:00



CASE 2: TRANSLUCENT BLADES 85o TILTED W: 55CM I VT: 0.15 MEAN ILLUMINANCE: 641 LUX

     











 





    Fig5.6 Section of illuminance for different shading strategies under the sunny sky Source: Ladybug + Honeybee CASE 3: HORIZONTAL BLADES 65o TILTED W: 55CM I R: 0.85 MEAN ILLUMINANCE: 282 LUX

Fig5.7 Illuminance of Case 2: Translucent Blades in sunny weather Source: Ladybug + Honeybee N LUX 0

150

300

450

600

750

900

1050

1200

1350

>1500

Fig5.8 Studied shading strategies under the sunny sky Source: Ladybug + Honeybee

94

ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

5.1.2 EAST FACADE

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

5.1.2 EAST

OVERCAST I SEP 21 I 10:00 CASE 1: NO SHADING MEAN ILLUMINANCE: 681 LUX

For this orientation, the horizontal and vertical shading devices were tested.

As noted in the previous chapters, many offices are not occupied early in the morning. Therefore, it might not be necessary to employ vertical shading elements to block the low angle sunlight.

Figure5.10 shows that the horizontal foldable panel performed slightly better than the vertical louvers. On the other hand, both cases had the same effect when horizontal panels and vertical louvers were closed (Fig5.13). The illuminance level inside did not exceed 2000 lux even near the window pane.

Therefore, the values were within the acceptable limits.

It is indicated in the literature review that the glare could be tolerated to some extent when uninterrupted visual contact with the outside is provided.

Since vertical shading impaired the view and homogeneity of the illuminance within the space, horizontal foldable panel was selected (see Appendix9.3).

OVERCAST 21 SEPTEMBER I 10:00

 

CASE 2: HOR. FOLDABLE PANEL FOLDED I W: 190CM I VT: 0.15 MEAN ILLUMINANCE: 452 LUX

     











 



    Fig5.10 Section of illuminance for different shading strategies under the overcast sky Source: Ladybug + Honeybee

CASE 3: VERTICAL SHADING 42O TILTED I W: 145CM I VT: 0.15 MEAN ILLUMINANCE: 380 LUX

42o Fig5.9 Studied shading strategies under the overcast sky Source: Ladybug + Honeybee

Fig5.11 Illuminance of Case 2: Translucent Horizontal Foldable Panel in overcast weather Source: Ladybug + Honeybee

N

LUX 0

150

300

450

600

750

900

1050

1200

1350

>1500

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

ECE DURMAZ

95

90 80 70

58o

60

SUNNY I SEP 21 I 10:00

50

CASE 1: NO SHADING MEAN ILLUMINANCE: 4760 LUX

40 30 20 10 120

90 East

60

30

0 South

30

60

0 120

90 West

HORIZONTAL FOLDABLE PANEL VSA: 58o

Fig5.12 Vertical shadow angle of horizontal foldable panel when it is folded Source: Climate Consultant

SUNNY 21 SEPTEMBER I 10:00



CASE 2 & 3: PANEL I LOUVERS CLOSED CLOSED I VT: 0.15 MEAN ILLUMINANCE: 554 LUX

      











 





   Fig5.13 Section of illuminance for different shading strategies under the sunny sky Source: Ladybug + Honeybee

Fig5.14 Illuminance of Case 2: Translucent Horizontal Foldable Panel in sunny weather Source: Ladybug + Honeybee

N

LUX 0

150

300

450

600

750

900

1050

1200

1350

>1500

Fig5.15 Studied shading strategies under the sunny sky Source: Ladybug + Honeybee

96

ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

5.1.3 WEST FACADE OVERCAST I SEP 21 I 14:00 CASE 1: NO SHADING MEAN ILLUMINANCE: 630 LUX CASE 2: TRAN. FOLDABLE PANEL FOLDED I W: 145CM I VT: 0.15 MEAN ILLUMINANCE: 520 LUX

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

5.1.3 WEST The west orientation requires protection from the low solar angles in order to block direct sunlight during the occupied periods. Since occupancy hours do not help to overcome this problem, the horizontal shading devices were excluded from this study. Instead, the impact of different vertical shading devices and materials were analysed.

Figure5.17 illustrates that all cases performed similarly under overcast sky. On the other hand, foldable panel provided a better distribution under sunny sky since illuminance level next to window was reduced below 2000 lux while minimum standard was provided for the rest of the space (Fig5.19). The same result could be achieved through tilting translucent vertical shading devices. In order to have an effective solar control, it is imperative to have operable shading elements that would follow the change in sky condition.

Providing more opportunity in terms of tilting angle, vertical shading devices were selected for the west facade.

OVERCAST 21 SEPTEMBER I 14:00

  

CASE 3: TRAN. SHADING OPEN I W: 145CM I VT: 0.15 MEAN ILLUMINANCE: 519 LUX

    









 





     Fig5.17 Section of illuminance for different shading strategies under the overcast sky Source: Ladybug + Honeybee CASE 4: VERTICAL SHADING OPEN I W: 145CM I R: 0.85 MEAN ILLUMINANCE: 507 LUX

Fig5.18 Illuminance of Case 2: Translucent Horizontal Foldable Panel in overcast weather Source: Ladybug + Honeybee Fig5.16 Studied shading strategies under the overcast sky Source: Ladybug + Honeybee

N

LUX 0

150

300

450

600

750

900

1050

1200

1350

>1500

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

ECE DURMAZ

97

SUNNY I SEP 21 I 14:00 CASE 1: NO SHADING MEAN ILLUMINANCE: 6268 LUX CASE 2: TRAN. FOLDABLE PANEL CLOSED I W: 145CM I VT: 0.15 MEAN ILLUMINANCE: 690 LUX

SUNNY 21 SEPTEMBER I 14:00

   

CASE 3: TRAN. SHADING 65o TILTED I W: 145CM I VT: 0.15 MEAN ILLUMINANCE: 768 LUX

    











 



    

65o

Fig5.19 Section of illuminance for different shading strategies under the sunny sky Source: Ladybug + Honeybee CASE 4: VERTICAL SHADING 65o TILTED I W: 145CM I R: 0.85 MEAN ILLUMINANCE: 434 LUX

65o

Fig5.20 Illuminance of Case 2: Translucent Horizontal Foldable Panel in sunny weather Source: Ladybug + Honeybee

N

LUX 0

150

300

450

600

750

900

1050

1200

1350

>1500

Fig5.21 Studied shading strategies under the sunny sky Source: Ladybug + Honeybee

98

ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

5.1.4 NORTH FACADE OVERCAST I JUN 21 I 17:00 CASE 1: NO SHADING MEAN ILLUMINANCE: 406 LUX

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

5.1.4 NORTH The vertical shading devices were examined since this facade receives low angle sun throughout the year. The climate study showed that the north facade was exposed to quite a low amount of solar radiation. Therefore, visible transmittance (VT) values of shading devices were increased to 0.25.

As seen in the Figure5.23, illuminance levels were reduced when any solar protection was applied. Therefore, shading devices were not required for the north facade under the overcast sky. On the other hand, the area half a meter from the facade was under the risk of over illuminance when solar protection was not used in the sunny weather (Fig5.25, Fig5.26). This issue could be easily eliminated with the admission of internal rollers and adjustments in the layout. To minimize the usage of artificial lighting, “no shading case” was selected for this orientation.

OVERCAST 21 SEPTEMBER I 10:00

 

CASE 2: TRAN. FOLDABLE PANEL FOLDED I W:145CM I VT: 0.25 MEAN ILLUMINANCE: 329 LUX

     











 

    Fig5.23 Section of illuminance for different shading strategies under the overcast sky Source: Ladybug + Honeybee

CASE 3: TRAN. VERT. SHADING OPEN I W:190CM I VT: 0.25 MEAN ILLUMINANCE: 303 LUX

Fig5.24 Illuminance of Case 1: No Shading in overcast weather Source: Ladybug + Honeybee

Fig5.22 Studied shading strategies under the overcast sky Source: Ladybug + Honeybee

N LUX 0

150

300

450

600

750

900

1050

1200

1350

>1500

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

ECE DURMAZ

99

SUNNY I JUN 21 I 17:00 CASE 1: NO SHADING MEAN ILLUMINANCE: 1153 LUX

SUNNY 21 SEPTEMBER I 10:00

  

CASE 2: TRAN. FOLDABLE PANEL HALF FOLDED I VT: 0.25 MEAN ILLUMINANCE: 593 LUX

     











 

    Fig5.25 Section of illuminance for different shading strategies under the sunny sky Source: Ladybug + Honeybee

CASE 3: TRAN. VERT. SHADING 25O TILTED I W:190CM I VT: 0.25 MEAN ILLUMINANCE: 598 LUX

Fig5.26 Illuminance of Case 1: No Shading in sunny weather Source: Ladybug + Honeybee

25o

N LUX 0

150

300

450

600

750

900

1050

1200

1350

>1500

Fig5.27 Studied shading strategies under the sunny sky Source: Ladybug + Honeybee

100

ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

5.2 DAYLIGHT ANALYSIS PART II

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

DEFINING THE SHOE-BOX: DETERMINING THE DEPTH Possible depth and layout of the office environments were studied after determining the shading devices for each orientation. The new shoe-box performs two sided, therefore, plan depth was increased from 6m to 8m/10m (Fig5.28). The building design was based on the Forum Chriesbach studied in Built Precedents Chapter. 3-sided atrium, facing west for south and north facade studies, provides additional daylight and minimizes the contrast in the room. Vertical shading devices with 0.25 VT value were used for atrium top and vertical glazing in the atrium (Table5.3). Orientation of the atrium was changed to north during west and east facade studies. In this case, shading

Table5.2 Selected operable external shading devices for each facade

SOUTH

EAST

WEST

NORTH

TRANSLUCENT BLADES

T. HOR. FOLDABLE PANEL

TRANSLUCENT SHADING

NO SHADING

OVERCAST

65o

SUNNY

Table5.3 Daylight simulation parameters

GENERAL

TRANSMITTANCE

RADIANCE PARAMETERS

Area

135m2

Glazing - External

0.65

-ab

4

Clear height

3.2m

Glazing - Internal

0.85

-ad

256

WWR

50%

Atrium Shading

0.25

-as

128

Occupancy hours

09:00 - 18:00

(west facing)

-ar

128

Orientation

Varies

-aa

0.25

Shading

Yes (Varies)

Context

Yes (Varies)

REFLECTANCE Wall

0.65

Floor

0.45

Ceiling

0.85

Furniture

0.60

Neighbour Building 0.45

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

ECE DURMAZ

101

devices were only applied for windows at atrium top and north facade left unprotected. In all cases 1.5m depth corridor in the atrium was considered for the circulation. Since windows at the atrium side were not exposed to outdoor conditions, glazing with 0.85 visible transmission value were used.

The aim of these studies was to discover the effect of context, different depths and WWR. For each orientation different office layout was proposed to eliminate glare on the working plane. The daylighting performance of the selected designs was evaluated by employing useful daylight illuminance (UDI) and glare simulations.

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  

Fig5.28 Configuration of new shoe-box model to determine depth of the place

102

ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

5.2.1 SOUTH FACADE

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

5.2.1 SOUTH Figure5.29 shows that the daylight factor was reduced by 2% - 4% when surrounding buildings were considered. Although the results were below the standard for 10 m depth, this case was selected since low daylight levels at the middle part of the room could be solved with a well-designed layout.

Therefore, a wide corridor space was left at the center while workstations were placed close to the facades (Fig5.30).

SELECTED CASE TRANSLUCENT BLADES MID - PART 30o TILTED W: 55CM I VT: 0.15

As seen in the Figure5.33, glare did not occur on the working plane during the critical hours of this facade. Daylight Glare Probability (DGP) values were below 0.35 for the both states of shading devices which correspond to the imperceptible glare.

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 Fig5.29 Daylight factor analysis for to investigate the effect of depth and context Source: Ladybug + Honeybee

 

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indoor



outdoor Fig5.30 Office layout designed according to daylight factor simulation results



DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

ECE DURMAZ

UDI (100 - 2000 LUX)

103

OVERCAST SKY STATE 10 9 8 7

TRANSLUCENT BLADES MID - PART 30o TILTED W: 55CM I VT: 0.15 UDI (100 - 2000 LUX): 78% MEAN DA (300 LUX): 83%

6 5 4 3 2 1 M

Fig5.31 UDI between 100-2000lux when shading devices are adjusted for overcast sky condition Source: Ladybug + Honeybee

UDI (100 - 2000 LUX)

SUNNY SKY STATE 10 9 8 7

TRANSLUCENT BLADES 85o TILTED W: 55CM I VT: 0.15 UDI (100 - 2000 LUX): 77% MEAN DA (300 LUX): 46%

6 5 4 3 2 1 M

Fig5.32 UDI between 100-2000lux when shading devices are adjusted for sunny sky condition Source: Ladybug + Honeybee N %

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OVERCAST SKY STATE I DGP: 0.31

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100

SUNNY SKY STATE I DGP: 0.25

Fig5.33 Glare analysis of office space under different adjustment of shading devices, SEP 21 I 12:00 Source: Ladybug + Honeybee CD/M2

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900

1000

DAYLIGHT GLARE PROBABILITY imperceptible glare: DGP<0.35 perceptible glare: 0.35<DGP<0.4 intolerable glare: DGP>0.45

104

ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

5.2.2 EAST FACADE

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

5.2.2 EAST The impact of the context on daylight factor was observed within 6m from the facade for the both cases. It is known that the daylight factor does not change with the orientation because it is the light level inside a building to the light level outside under overcast sky. Since outdoor illuminance on a horizontal plane was same for the all cases, various results for the different facades can be explained with the impact of shading devices on the visible sky component (SC) and externally reflected component (ERC) which have a direct relation with the interior daylight level.

SELECTED CASE HORIZONTAL FOLDABLE PANEL FOLDED I W: 190CM I VT: 0.15

Fig5.34 shows that the office, 10m in depth, provided minimum daylight requirement even in the middle part of the room. Therefore, this case was selected for the east orientation. UDI level (between 100 - 2000 lux for the active occupant behaviour) was below 50% within 1m from the exterior window when shading panel was kept folded (Fig5.36). Therefore, 1m set back distance was left from the facade to prevent over illuminance (Fig5.35).

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

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

 Fig5.34 Daylight factor analysis for to investigate the effect of depth and context Source: Ladybug + Honeybee

 

  

indoor



outdoor Fig5.35 Office layout designed according to daylight factor simulation results



DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

ECE DURMAZ

UDI (100 - 2000 LUX)

105

OVERCAST SKY STATE 10 9 8 7

HORIZONTAL FOLDABLE PANEL FOLDED I W: 190CM I VT: 0.15 UDI (100 - 2000 LUX): 73% MEAN DA (300 LUX): 71%

6 5 4 3 2 1 M Fig5.36 UDI between 100-2000lux when shading devices are adjusted for overcast sky condition Source: Ladybug + Honeybee

UDI (100 - 2000 LUX)

SUNNY SKY STATE 10 9 8 7

HORIZONTAL FOLDABLE PANEL CLOSED I VT: 0.15 UDI (100 - 2000 LUX): 67% MEAN DA (300 LUX): 39%

6 5 4 3 2 1 M Fig5.37 UDI between 100-2000lux when shading devices are adjusted for sunny sky condition Source: Ladybug + Honeybee N

%

0

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30

40

50

60

70

OVERCAST SKY STATE I DGP: 0.28

80

90

100

SUNNY SKY STATE I DGP: 0.24

Fig5.38 Glare analysis of office space under different adjustment of shading devices, SEP 21 I 10:00 Source: Ladybug + Honeybee CD/M2

0

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300

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1000

DAYLIGHT GLARE PROBABILITY imperceptible glare: DGP<0.35 perceptible glare: 0.35<DGP<0.4 intolerable glare: DGP>0.45

106

ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

5.2.3 WEST FACADE

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

5.2.3 WEST The minimum requirement of 2% daylight factor could be achieved for this orientation even when the depth was extended to 10m (Fig5.39). Therefore, 10 m depth was selected for the west oriented office space. Figure5.41 shows that UDI values were above 50% for the middle part of the room. Due to the nature of the vertical shading devices, UDI pattern was not homogenous within 1m of the facade. Hence, the layout was arranged to consider this distance as a setback (Fig5.40).

SELECTED CASE TRANSLUCENT SHADING OPEN I W: 145CM I VT: 0.15

The UDI simulation reveals that glare next to facade can be eliminated without compromising useful illuminance levels when shading devices were tilted 65O (Fig5.42) This finding was also supported with the glare analysis showing that DGP value was below 0.35 during the sunny state of the vertical louvers (Fig5.43 right).

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

 Fig5.39 Daylight factor analysis for to investigate the effect of depth and context Source: Ladybug + Honeybee  

  

indoor



outdoor Fig5.40 Office layout designed according to daylight factor simulation results



DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

ECE DURMAZ

UDI (100 - 2000 LUX)

107

OVERCAST SKY STATE 10 9 8 7

TRANSLUCENT SHADING OPEN I W: 145CM I VT: 0.15 UDI (100 - 2000 LUX): 75% MEAN DA (300 LUX): 68%

6 5 4 3 2 1 M

Fig5.41 UDI between 100-2000lux when shading devices are adjusted for overcast sky condition Source: Ladybug + Honeybee

UDI (100 - 2000 LUX)

SUNNY SKY STATE 10 9 8 7

TRANSLUCENT SHADING 65o TILTED I W: 145CM I VT: 0.15 UDI (100 - 2000 LUX): 74% MEAN DA (300 LUX): 52%

6 5 4 3 2 1

65o

M

Fig5.42 UDI between 100-2000lux when shading devices are adjusted for sunny sky condition Source: Ladybug + Honeybee N

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Fig5.43 Glare analysis of office space under different adjustment of shading devices, SEP 21 I 14:00 Source: Ladybug + Honeybee CD/M2

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DAYLIGHT GLARE PROBABILITY imperceptible glare: DGP<0.35 perceptible glare: 0.35<DGP<0.4 intolerable glare: DGP>0.45

108

ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

5.2.4 NORTH FACADE

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

5.2.4 NORTH Achieving the daylight requirement was challenging because of the small amount of solar insolation falling to this facade. As seen in the Figure5.44, daylight factor reached up to 25% since the facade was unprotected. However, middle part of the space was still below the daylight factor threshold of 2%, in the case of 10 m depth. Hence, office space, 8 m in depth, was selected for this orientation.

SELECTED CASE NO SHADING

Low UDI values indicate that the area next to window pane was under the risk of over illumination (Fig5.46). Therefore, workstations were positioned at a distance of 1.4-meter from the facade (Fig5.45). The daylight quality of the working environment was assessed through a glare simulation. Figure5.47 shows that DGP value was in the acceptable limits for the problematic hour of north facade.

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 Fig5.44 Daylight factor analysis for to investigate the effect of depth and context Source: Ladybug + Honeybee

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outdoor Fig5.45 Office layout designed according to daylight factor simulation results

  

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

ECE DURMAZ

UDI (100 - 2000 LUX) M

109

NO SHADING UDI (100 - 2000 LUX): 71% MEAN DA (300 LUX): 85%

1 2 3 4 5 6 7 8 Fig5.46 UDI between 100-2000lux when shading devices are adjusted for no shading case Source: Ladybug + Honeybee N %

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Fig5.47 Glare analysis of office space under no shading condition, JUN 21 I 17:00 Source: Ladybug + Honeybee CD/M2

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DAYLIGHT GLARE PROBABILITY imperceptible glare: DGP<0.35 perceptible glare: 0.35<DGP<0.4 intolerable glare: DGP>0.45

110

ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

5.3 THERMAL ANALYSIS

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

DEFINING THE SHOEBOX After determining shading strategy for each orientation, the next step was carried out to verify how such an office space with passive design strategies underlined in the literature review and built precedents chapters would perform. Regarding the daylight simulation results, the shoebox 10m deep was used for all orientations for the ease of comparison.

The occupant density (7.2 m2/person) was determined according to the workstation layout proposed in the daylight analysis. Considering the previous findings, 80% of the workstations were set as occupied during the working hours. Additionally, lighting and equipment power density were adjusted regarding the literature (Fig5.49).

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Fig5.48 Configuration of base model

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Fig5.49 Internal gains breakdown for a typical week day in current scenario Source: OpenStudio + EnergyPlus

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Fig5.50 Internal loads defined for current and two future scenarios Source: OpenStudio + EnergyPlus

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

ECE DURMAZ

Studied 3 envelopes with different infiltration rates reflected various construction cases in Ankara (Table5.4). The Case A envelope provides minimum standards of TS 825 Regulation for Region III. On the other hand, Case B showed features of a typical construction in Ankara with an average envelope u-value. Finally, Case C was created by based on Eawag Forum Chriesbach building, Switzerland. The external wall u-value was increased from 0.12 to 0.17, because of high initial cost and applicability reasons in building sector of Turkey. Additionally, WWR was considered as 75% in Case A and 50% in Case B & C. A colour code was assigned to the thermal simulation graphs according to the envelope type. Therefore, Case A, B and C envelopes were indicated with shades of green, pink, and blue respectively. Additionally, the same colour code with daylight analysis parts were used for different orientations.

Table5.4 3 envelopes defined for thermal simulations

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





CASE A

CASE B

CASE C

area

225m2

225m2

225m2

volume

720m3

720m3

720m3

window to wall ratio

75%

50%

50%

occupied hours

09:00 - 18:00

09:00 - 18:00

09:00 - 18:00

weekdays only

weekdays only

weekdays only

occupancy density

7.2 m2/person

7.2 m2/person

7.2 m2/person

lighting power density

7 W/m2

7 W/m2

7 W/m2

equipment power density

12 W/m2

12 W/m2

12 W/m2

infiltration

0.75 ACH

0.5 ACH

0.3 ACH

fresh air requirement

1.03 ACH

1.03 ACH

1.03 ACH

ext. wall u value

0.5 W/m2K

0.5 W/m2K

0.17 W/m2K

glazing u value

2.5 W/m2K

1.55 W/m2K

1.55 W/m2K

111

112

ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

THERMAL ANALYSIS METHODOLOGY The analytic studies undertaken hereafter were carried out to create design guidelines for the offices in Ankara. A set of variables; context, shading devices, night time cooling, ventilation strategies and internal gains were studied in different construction systems to quantify the number of hours in comfort (Fig5.52). It was aimed to see the possibility of maximum free-running period with a cumulative study. For this, the selected case from the former analysis created a new base for the latter in a successive analysis process. Therefore, it was aimed to get realistic and comparable results at the end of this chapter.

The weather file was generated via Meteonorm 7, which has measurements for a 30year period. For the Case 5 future studies, 2050 A2 scenario was used. Energy analysis of the studied cases were done by EnergyPlus, which is a well-known dynamic energy simulation tool. This software was used together with Open Studio plugin for Google SketchUp to calculate the annual energy consumption. The comfort band was based on the EN 15251 Type II equation which was mentioned in the Context & Climate Chapter.

In order to assess the need for a mechanical system and the estimated loads, the heating and cooling set points below were used. After thorough calculations, the set points were re-adjusted for the naturally ventilated cases in compliance with EN 15251 adaptive thermal comfort band (Fig5.51). It was aimed to reveal the impact of adaptive comfort and natural ventilation in the offices with this study.

Heating set point: 20oC Heating set point: 26oC

Fig5.51 Adaptive comfort band for June according to EN15251 adaptive comfort methodology shows the 28oC set point within the range of comfort Source: CBE Thermal Comfort Tool

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

1. CONTEXT CASE 1.1: BASE

30o

50o

CASE 1.2: 1.1 + 30O OBSTRUCTION ANGLE

CASE 1.3: 1.1 + 50O OBSTRUCTION ANGLE

+ 2. SHADING STRATEGY CASE 2.1: 1.2 + BALCONY & T. BLADES SOUTH FACADE I W:55CM I VT:0.15 CASE 2.2: 1.2 + BALCONY & BLADES SOUTH FACADE I W:55CM SELECTED CASE FOR EACH ORIENTATION

CASE 2.3: 1.2 + T. FOLDABLE PANEL EAST FACADE I H:190CM I VT:0.15 CASE 2.4: 1.2 + T. VERTICAL SHADING EAST & WEST FACADE I W:145CM I VT:0.15 CASE 2.5: 1.2 + VERTICAL SHADING WEST FACADE I W:145CM

+ 3. NIGHT SHUTTER CASE 3.1: SELECTED CASE 2 + NIGHT SHUTTER THERMAL CONDUCTIVITY: 0.04 W/MK

+ 4. NATURAL VENTILATION CASE 4.1: 3.1 + 1 SIDED VENTILATION

CASE 4.2: 4.1 + CROSS VENTILATION

CASE 4.3: 4.2 + NIGHT COOLING

+ 5. FUTURE SCENARIO CASE 5.1: ENERGY CONSCIOUS + 4.3 LIGHTING LOAD: 4W/M2 EQUIPMENT LOAD: 6W/M2 CASE 5.2: TECHNO ERA + 4.3 LIGHTING LOAD: 4W/M2 EQUIPMENT LOAD: 22W/M2 Fig5.52 Studied parameters for thermal simulations

ECE DURMAZ

113

114

ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

5.3.1 SOUTH FACADE CASE 1.1: BASE

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

1. CONTEXT The following set of simulations investigated the effect of context in typical winter and summer days. The base case in an unobstructed environment had higher internal operative temperatures in all cases, as expected (Fig5.54).

The dramatic effect of high obstructing structure was observed clearly in winter months due to low solar altitude. The temperature difference between base and 50o obstructed case reached up to 7K in overcast conditions and 12K on sunny days for Case C envelope (Fig5.54). Additionally, the daytime temperature of highly obstructed cases remained the same regardless of the weather condition. This shows that an obstruction angle of 30o allows the south facade to receive most of the solar radiation, whereas an angle of 50o blocks majority of the sunlight during winter.

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



















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Fig5.54 Thermal analysis of 3 envelopes in a different context for typical winter days Source: EnergyPlus

Above Comfort Belove Comfort Fig5.53 Number of hours out of comfort Source: EnergyPlus

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

Figure5.55 shows that all cases were above the comfort since the shading devices and/or ventilation were not applied in typical summer days. There was a 1K temperature difference between the unobstructed and obstructed cases. In contrast to the typical winter week, the change in obstruction angle did not help to reduce summer solar gains due to the high solar altitude. Therefore, the obstructions in this orientation should be minimized, if possible.

ECE DURMAZ

115

CASE 1.3: 1.1 + 50O OBSTRUCTION ANGLE

Since it reflected the urban context in a more realistic manner, Case1.2 (30o obstruction angle) was considered for the rest of the studies.

50o

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





















Fig5.55 Thermal analysis of 3 envelopes in a different context for typical summer days Source: EnergyPlus

Above Comfort Belove Comfort Fig5.56 Number of hours out of comfort Source: EnergyPlus

116

ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

5.3.1 SOUTH FACADE CASE 2.1: 1.2 + BALCONY & TRANLUCENT BLADES

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

2. SHADING STRATEGY The effects of different shading materials were analysed for the south facade. As seen in Figure5.58, the impact of solid and translucent materials was dominated by the overhang/balcony. During summer time, the operative temperature could be reduced by 4.5K in Case C, but it was only 2.5K in Case A. This result was expected since the leaky buildings were already loosing huge amount of heat through the infiltration. All cases still needed to be naturally ventilation due to the high internal temperature.

These shading devices created a penalty of around 3K and 5K for overcast and sunny days during the winter period respectively. The reduction in solar gains pushed Case A below the comfort band with 300 hours increase in heating hours. This penalty was only 120 hours for Case C office.

Since both shading devices thermally did not create a significant difference, the best performing one with regards to daylight (Case2.1: balcony + translucent blades) was selected.

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CASE 2.2: 1.2 + BALCONY & BLADES

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Fig5.58 Effect of shading strategies for typical winter (left) and summer (right) days Source: EnergyPlus

Above Comfort Belove Comfort Fig5.57 Number of hours out of comfort Source: EnergyPlus

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

ECE DURMAZ

117

3. NIGHT SHUTTER Night shutters, with a thermal conductivity of 0.04 W/mK, were applied from November to mid-April. Figure5.59 shows that the efficacy of night shutters had a direct relation with the building envelope. 0.5K increment was observed for Case A envelope whereas this value reached to 2K for Case C. Therefore, it is important to have a well-sealed envelope to get the most benefit from night shutters and minimize the indoor temperature fluctuations.

CASE 3.1: 2.1 + NIGHT SHUTTER

If natural ventilation was not introduced for the winter months, the number of overcast and sunny days could be considered while designing the extremely sealed facades since overheating might be a problem, especially on sunny winter days.

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Fig5.59 Effect of night shutters for typical winter days Source: EnergyPlus

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NIGHT SHUTTERS: NOVEMBER - MID-APRIL Above Comfort Belove Comfort Fig5.60 Number of hours out of comfort Source: EnergyPlus

118

ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

5.3.1 SOUTH FACADE CASE 4.1: 3.1 + 1 SIDED VENTILATION

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

4. NATURAL VENTILATION This set of simulations investigated the different ventilation strategies. Regarding the findings of Ugursal (2003) in Emek Building, Ankara, ventilation was applied from May to October. It was observed that Case A office could be in comfort even with onesided ventilation due to the high infiltration values (Fig5.62 left). However, overheating was still an issue for Case B and C during sunny days.

As mentioned in the climate studies, the diurnal temperature difference – 13K in the selected days – creates a perfect opportunity to cool down the space at night time. Figure5.62 and Figure5.63 shows that Case4.3 (cross ventilation + night time cooling) performed best in all cases, as expected. Since the internal temperature

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















































CASE 4.2: 4.1 + CROSS VENTILATION

 





 





































Fig5.62 Comparison of different ventilation strategies on Case A (left) and Case B (right) envelope Source: EnergyPlus

Above Comfort Belove Comfort Fig5.61 Number of hours out of comfort Source: EnergyPlus

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

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119

followed a similar pattern with the outdoor temperature during the occupied time, it was concluded that Case4.3 used the benefits of ventilation as much as possible. The greatest decrement in operative temperature was 7K in Case C envelope, whereas this was 5K for Case A and B. As seen in the Figure5.64 non- ventilated offices were in comfort for less than 30% of the occupied time which increased the dependence on HVAC systems. Comfort levels could be increased significantly when cross ventilation and night time cooling are introduced. All in all, it was found that an office using passive means of sustainable principles could be free-running for 72% of the occupied time in Ankara (Case 4.3C).

















 





 







 













 





  









 











 







 

CASE 4.3: 4.2 + NIGHT COOLING









 









 



 



  

 









 

























 





 









Fig5.63 Comparison of different ventilation strategies on Case C envelope Source: EnergyPlus

Fig5.64 Percentage of occupied hours within comfort according to EN15251 Standard Catergory II Source: AA SED Spreadsheet

NATURAL VENTILATION PERIOD: MAY - OCTOBER Above Comfort Belove Comfort Fig5.65 Number of hours out of comfort Source: EnergyPlus

120

ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

5.3.1 SOUTH FACADE CASE 5.1: ENERGY CONSCIOUS + 4.3

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

5. FUTURE SCENARIO A sustainable office space should adapt to the future climate change and working environments. As mentioned in the climate study, a temperature rise of 2oC is expected for the 2050 scenario. A new comfort band was set according to the EN 15251 – Type II standard. In order to assess the need of estimated loads, similar set points were used as the comfort limit mentioned in 2050 climate studies. The ventilation study in the previous section showed that day time cross ventilation + night time cooling performed best in Ankara. Therefore, this case was considered to overcome the effect of climate change in the future.

The literature research revealed that there are two future scenarios (Generation 5.1 and 5.2) where internal gains were changed, and hot desking were introduced. The inputs were adjusted as seen in Figure5.66 and Figure5.69.

CHANGED INPUTS

 



 





 

DAY TIME OCCUPANCY: 80% -> 90%



LIGHTING LOAD: 7W/M2 -> 4W/M2









EQUIPMENT LOAD: 12W/M2-> 6W/M2









FRESH AIR REQUIREMENT: 1.03 ACH -> 1.16 ACH



















































 







 





















Fig5.67 Comparison of two future scenarios with different internal gains on Case A (left) and Case B (right) envelope Source: EnergyPlus

Above Comfort Belove Comfort Fig5.66 Number of hours out of comfort Source: EnergyPlus

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

ECE DURMAZ

121

The results showed that the internal gain change had an impact on the operative temperature both in summer and winter. The outdoor temperature exceeding the comfort band could make night time cooling necessary in the future. In both scenarios, the windows were closed during daytime to keep the office cool.

During winter, the increase in temperature and internal gains created overheating problems for the airtight envelopes (Case5.2B, 5.2C). Therefore, ventilation period could be extended if high internal gains were expected in the future. On the other hand, the rise in the outdoor temperature would not be enough to compensate the decrease in internal gains as seen in the energy conscious scenario. In this case, only Case C could stay in comfort (Fig5.68).

 





 



CASE 5.2: TECHNO ERA + 4.3

CHANGED INPUTS







DAY TIME OCCUPANCY: 80% -> 90%









LIGHTING LOAD: 7W/M2 -> 4W/M2









EQUIPMENT LOAD: 12W/M2-> 22W/M2









FRESH AIR REQUIREMENT: 1.03 ACH -> 1.16 ACH









































 



  



 



 

 

 

   

Fig5.68 Comparison of two future scenarios with different internal for Case C envelope (left) and result of typical winter days simulation Source: EnergyPlus

NATURAL VENTILATION PERIOD: MAY - OCTOBER Above Comfort Belove Comfort Fig5.69 Number of hours out of comfort Source: EnergyPlus

122

ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

5.3.1 SOUTH FACADE

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

COMPARISON OF THE LOADS & OPTIMIZATION Heating and cooling consumption of the selected cases were compared for the studied envelopes. Figure5.70 shows that having a context did not have a significant impact on cooling consumption due to high sun angle in summer. On the other hand, heating loads were increased, especially for the leaky Case A envelope. Although the office buildings are internal load dominated spaces, selection of a good passive solar site can still reduce the heating consumption in Ankara.

Having a solar protection reduced the cooling energy usage significantly, which was around 25 kWh/m2 for Case C envelope with a penalty of 7 kWh/m2 in heating.

Night shutters performed well for all the envelopes without creating any penalty since it was used seasonally.

Impact of the natural ventilation, applied from May to October, showed a great variety depending on the strategy. The negative effect of the airtightness on overheating problem was minimized when cross ventilation and night time cooling was used together.

The last step was carried out to show the importance of the adaptive comfort. In this case, set points were readjusted for the naturally ventilated period according to the EN15251 adaptive comfort band. In all cases, the cooling load consumptions were reduced more than 60%.

To conclude, it is possible to reduce cooling consumption around 92% for the south facing offices if the passive measures were applied during the design stage.

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

28oC 20oC

30o







ECE DURMAZ



 

 

 





 

123

Heating Load Cooling Load

 

  



  



 



 







 















 

 

 











   





 



  





 





 























  







 

 

 

















 



 



 





Fig5.70 Heating and cooling load consumption for Case A, B and C envelopes Source: OpenStudio & EnergyPlus







 

124

ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

5.3.2 EAST FACADE CASE 1.1: BASE

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

1. CONTEXT The east facade followed a different trend than the south since it receives weak, low angle sun in the cold period. Additionally, the sun path diagram studied within the climate analysis revealed that the east and west facades are exposed to direct solar radiation for less time during winter. Hence, the change in the obstruction height (Case 1.2 and 1.3) did not have a significant impact on the winter operative temperatures (Fig5.72). Because of the low outdoor temperature and weak solar radiation, only Case C envelope stayed in the comfort band on typical winter days.



 



































CASE 1.2: 1.1 + 30O OBSTRUCTION ANGLE

30o



 







































Fig5.72 Thermal analysis of 3 envelopes in a different context for typical winter days Source: EnergyPlus

Above Comfort Belove Comfort Fig5.71 Number of hours out of comfort Source: EnergyPlus

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

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125

During summer time, the east facade is exposed to stronger solar radiation for a longer period. Due to the low summer sun altitude, this facade was more sensitive to change in the obstruction height than the south facade. The internal temperature could be reduced up to 8K for Case C envelope whereas this was around 5K for Case A. All cases suffered from overheating regardless of the envelope or context. Therefore, the shading and ventilation strategies must be considered for the offices facing east.

CASE 1.3: 1.1 + 50O OBSTRUCTION ANGLE

50o

 







































 







































Fig5.73 Thermal analysis of 3 envelopes in a different context for typical summer days Source: EnergyPlus

Above Comfort Belove Comfort Fig5.74 Number of hours out of comfort Source: EnergyPlus

126

ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

5.3.2 EAST FACADE

Two translucent shading devices introduced in daylight analysis were studied for this set of simulations. Both cases were simulated as in overcast conditions throughout the year.

CASE 2.3: 1.2 + TRANS. FOLDABLE PANEL

During winter, the vertical shading reduced the internal temperature slightly more since the folded horizontal panel was not very effective to block the low angle winter sun (Fig5.76 left).

2. SHADING STRATEGY

On the other hand, the horizontal foldable panel performed clearly better than the vertical shading in the typical summer days. The operative temperature was decreased approximately 1K when translucent vertical shading was used. However, the reduction reached up to 6K in the case of translucent foldable panel. Therefore, translucent foldable panel was selected for this orientation.

Overheating was observed in all cases. Therefore, natural ventilation should be introduced to the offices facing this orientation. 

 



 









































































CASE 2.4: 1.2 + TRANS. VERTICAL SHADING

 

 









































Fig5.76 Effect of shading strategies for typical winter (left) and summer (right) days Source: EnergyPlus

Above Comfort Belove Comfort Fig5.75 Number of hours out of comfort Source: EnergyPlus

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

ECE DURMAZ

127

3. NIGHT SHUTTER As observed in the context and shading strategy studies, winter solar gains were playing a small role for the east facade since the opposing building casts long shadow.

Therefore, the effect of the night shutters was observed clearly in this facade. The internal operative temperature of Case C was increased by 3.5K during the occupied period. However, only 2K increment was observed for the same case in the south facade studies. The night shutters were more effective for the airtight envelopes (Case C), as expected, since the heat loss through the facades was minimized.

CASE 3.1: 2.1 + NIGHT SHUTTER

Additionally, internal temperature fluctuations reduced in all cases.



 





































 





























Fig5.77 Effect of night shutters for typical winter days Source: EnergyPlus





NIGHT SHUTTERS: NOVEMBER - MID-APRIL Above Comfort Belove Comfort Fig5.78 Number of hours out of comfort Source: EnergyPlus

128

ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

5.3.2 EAST FACADE CASE 4.1: 3.1 + 1 SIDED VENTILATION

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

4. NATURAL VENTILATION The figures below show the variation in internal temperature for different ventilation strategies. This study revealed the limited efficacy of one-sided ventilation alone to drop the operative temperature below the upper limit of comfort. Even in a leaky envelope (Case A), overheating might be a problem on sunny days.

Case 4.3 (cross vent + night time cooling) was the most effective passive strategy in all cases, as expected. The internal temperature could be decreased by 6K, 7K and 8K for Case A, B and C, respectively. This would significantly increase the occupant comfort during working hours. As seen in the columns on the left and right sides of

  





 











































































CASE 4.2: 4.1 + CROSS VENTILATION

 





 





































Fig5.80 Comparison of different ventilation strategies on Case A (left) and Case B (right) envelope Source: EnergyPlus

Above Comfort Belove Comfort Fig5.79 Number of hours out of comfort Source: EnergyPlus

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

ECE DURMAZ

129

the pages, overheating hours were reduced by 924 hours for Case A, and 1287 hours for Case C. Additionally, the temperature exceeding comfort zone for 3K was not more than 6 hours in all cases.

An east facing office in Ankara could be free-running for 65% of the time when cross ventilation and night time cooling were introduced (Fig5.82).

















 

 





 









  

 





 

 



















 















 







 

CASE 4.3: 4.2 + NIGHT COOLING







 





 



  

 













 









































Fig5.81 Comparison of different ventilation strategies on Case C envelope Source: EnergyPlus

Fig5.82 Percentage of occupied hours within comfort according to EN15251 Standard Catergory II Source: AA SED Spreadsheet

NATURAL VENTILATION PERIOD: MAY - OCTOBER Above Comfort Belove Comfort Fig5.83 Number of hours out of comfort Source: EnergyPlus

130

ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

5.3.2 EAST FACADE CASE 5.1: ENERGY CONSCIOUS + 4.3

CHANGED INPUTS

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

5. FUTURE SCENARIO Although cross ventilation and night time cooling were applied, overheating problem was observed for all cases with techno era scenario due to high outdoor temperature (Fig5.85, Fig5.86). The infiltration values show that windows of Case B and C offices were kept open despite the outdoor temperature exceeding the comfort level (June, 13th). However, Case A was below the outdoor temperature for the same day since it lost more heat through the leaky envelope. In all cases, the energy conscious office performed well in typical summer days.

 



 





 

DAY TIME OCCUPANCY: 80% -> 90%



LIGHTING LOAD: 7W/M2 -> 4W/M2









EQUIPMENT LOAD: 12W/M2-> 6W/M2









FRESH AIR REQUIREMENT: 1.03 ACH -> 1.16 ACH



















































 







 





















Fig5.85 Comparison of two future scenarios with different internal gains on Case A (left) and Case B (right) envelope Source: EnergyPlus

Above Comfort Belove Comfort Fig5.84 Number of hours out of comfort Source: EnergyPlus

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

ECE DURMAZ

131

During winter, only Case B and C envelopes with techno era scenario stayed in the comfort band (Fig5.86 right). Additionally, there was not a significant difference between sunny and cloudy days since effect of solar gains were minimized by the opposing building.

To sum up, a highly airtight building facing east might face overheating problems in the future. Therefore, dynamic shading devices are required to provide summer comfort without compromising winter performance.

 





 



CASE 5.2: TECHNO ERA + 4.3

CHANGED INPUTS







DAY TIME OCCUPANCY: 80% -> 90%









LIGHTING LOAD: 7W/M2 -> 4W/M2









EQUIPMENT LOAD: 12W/M2-> 22W/M2









FRESH AIR REQUIREMENT: 1.03 ACH -> 1.16 ACH









































 



  



 



 

 

 

   

Fig5.86 Comparison of two future scenarios with different internal for Case C envelope (left) and result of typical winter days simulation Source: EnergyPlus

NATURAL VENTILATION PERIOD: MAY - OCTOBER Above Comfort Belove Comfort Fig5.87 Number of hours out of comfort Source: EnergyPlus

132

ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

5.3.2 EAST FACADE

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

COMPARISON OF THE LOADS & OPTIMIZATION The heating and cooling consumption of the east oriented offices were compared in this part. Unlike the south facade, being in an urban context reduced the cooling loads significantly whereas heating loads increased not more than 5 kWh/m2 in all cases.

This result was expected since east facade is exposed to low angle summer sun.

As seen in the Figure5.88, application of shading devices reduced the cooling energy consumption with a higher efficacy in airtight Case C envelope. Considering these results and findings from the daylight studies, one can conclude that solar protection systems must be used for offices facing east.

Night shutters reduced the heating consumption by 16% in Case A. However, this value was increased to 20% for the Case C envelope due to the difference in the envelope.

The results of the natural ventilation studies for this facade shows similarity with the south. In all cases, cooling loads decreased more than 50%. The insignificant increase in heating loads resulted from a cold week during the mild period.

The last step shows that cooling energy usage could be reduced below 5 kWh/m2 when thermostat set point was rearranged according to adaptive comfort standards.

Therefore, the benefits of adaptive opportunities should be considered to minimize the energy consumption.

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

28oC 20oC

30o







ECE DURMAZ



 

 

 





 

133

Heating Load Cooling Load

 

   

 

























 















 







  







  









 







 

 

  





















 



 







 







 



 

 

 

 













Fig5.88 Heating and cooling load consumption for Case A, B and C envelopes Source: OpenStudio & EnergyPlus







 

134

ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

5.3.3 WEST FACADE CASE 1.1: BASE

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

1. CONTEXT The results show great similarity with the east facade since both orientations get high amount of solar radiation in summer but quite low in winter. The internal operative temperatures during winter decreased by 1 – 2K independently from the change in the obstruction angle. In this case, only Case C envelope stayed in the comfort band for most of the occupied time (Fig5.90).

On the other hand, the height of the obstruction had a directly proportional impact on summer operative temperatures. The temperatures could be reduced by 9K for the office buildings in a dense urban area (Fig5.91 - Case C).



 



































CASE 1.2: 1.1 + 30O OBSTRUCTION ANGLE

30o



 







































Fig5.90 Thermal analysis of 3 envelopes in a different context for typical winter days Source: EnergyPlus

Above Comfort Belove Comfort Fig5.89 Number of hours out of comfort Source: EnergyPlus

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

ECE DURMAZ

135

Despite the significant decrease in the temperature, all envelopes suffered from overheating. Therefore, the shading and natural ventilation possibilities must be studied for this facade.

CASE 1.3: 1.1 + 50O OBSTRUCTION ANGLE

50o

 







































 







































Fig5.91 Thermal analysis of 3 envelopes in a different context for typical summer days Source: EnergyPlus

Above Comfort Belove Comfort Fig5.92 Number of hours out of comfort Source: EnergyPlus

136

ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

5.3.3 WEST FACADE CASE 2.3: 1.2 + TRANS. VERTICAL SHADING

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

2. SHADING STRATEGY Unlike the east facade, it is required to block low angle sun since many offices are still occupied in the afternoon. Therefore, the vertical shading devices were studied for this orientation.

It was discovered that the translucent shading devices performed better than the solid ones, especially during the sunny winter day (Fig5.94 left). Hence, the translucent shading devices would be a better choice if the number of sunny days are more than the cloudy days in winter. In the context of Ankara, the solid shading devices increased the heating necessity by 255 hours whereas this was only 179 hours for the translucent shading in Case C office. (Fig5.89, Fig5.93).

During summer, both devices performed similarly with 2K reduction in operative temperature at most (Fig5.94 right). Summer solar radiation can be blocked more effectively when operable shading devices are used along with the weather track systems. Due to the strong solar radiation and occupancy patterns, adjustable shading devices should be introduced to this facade first if there is a limited budget.  





 









































































CASE 2.4: 1.2 + VERTICAL SHADING

 

 









































Fig5.94 Effect of shading strategies for typical winter (left) and summer (right) days Source: EnergyPlus

Above Comfort Belove Comfort Fig5.93 Number of hours out of comfort Source: EnergyPlus

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

ECE DURMAZ

137

3. NIGHT SHUTTER The internal operative temperature increased by 4K with the implementation of night shutters in the well-sealed Case C envelope. Similar to the other orientations, the efficacy dropped if the envelope has a high infiltration rate.

Due to the low outdoor temperatures and weak solar radiation, only Case C office remained in the comfort during the occupied hours.



 





































 

























CASE 3.1: 2.1 + NIGHT SHUTTER





Fig5.95 Effect of night shutters for typical winter days Source: EnergyPlus





NIGHT SHUTTERS: NOVEMBER - MID-APRIL Above Comfort Belove Comfort Fig5.96 Number of hours out of comfort Source: EnergyPlus

138

ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

5.3.3 WEST FACADE

In this set of simulations, various ventilation strategies were examined for envelopes with different infiltration rates. As seen in the figures below, overheating occurred for all envelopes when only 1-sided ventilation was applied (Case4.1).

CASE 4.1: 3.1 + 1 SIDED VENTILATION

Internal operative temperature could be reduced significantly with cross ventilation.

However, Case4.3B and C require night time cooling since the temperature exceeds the upper limit of comfort during a sunny summer day.

4. NATURAL VENTILATION

  





 











































































CASE 4.2: 4.1 + CROSS VENTILATION

 





 





































Fig5.98 Comparison of different ventilation strategies on Case A (left) and Case B (right) envelope Source: EnergyPlus

Above Comfort Belove Comfort Fig5.97 Number of hours out of comfort Source: EnergyPlus

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

ECE DURMAZ

139

Although Case4.3 (cross vent + night time cooling) performed best in all cases, as expected, envelope B and C had 1 - 2K higher internal temperatures than Case A due to the differences in airtightness.

A well-sealed office building facing this orientation did not require any heating or cooling for 57% of the occupied time. Although this value can increase with the implementation of dynamic solar protection systems, it still very low comparing to the other facades.

















 

 





 

















  





 











 















 





 

CASE 4.3: 4.2 + NIGHT COOLING



   

 







 

 



  

 









































 













Fig5.99 Comparison of different ventilation strategies on Case C envelope Source: EnergyPlus

Fig5.100 Percentage of occupied hours within comfort according to EN15251 Standard Catergory II Source: AA SED Spreadsheet

NATURAL VENTILATION PERIOD: MAY - OCTOBER Above Comfort Belove Comfort Fig5.101 Number of hours out of comfort Source: EnergyPlus

140

ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

5.3.3 WEST FACADE CASE 5.1: ENERGY CONSCIOUS + 4.3

CHANGED INPUTS

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

5. FUTURE SCENARIO All the cases overheated during a sunny afternoon due to the increase in outdoor temperature and strong direct solar radiation. Considering occupied hours of an office building and constraints to limit the solar radiation, the west facade is more problematic than the other orientations. The problem would become more crucial in the future, since the outdoor temperature is expected to rise. Therefore, the office spaces should not face this orientation, if possible.

 



 





 

DAY TIME OCCUPANCY: 80% -> 90%



LIGHTING LOAD: 7W/M2 -> 4W/M2









EQUIPMENT LOAD: 12W/M2-> 6W/M2









FRESH AIR REQUIREMENT: 1.03 ACH -> 1.16 ACH



















































 







 





















Fig5.103 Comparison of two future scenarios with different internal gains on Case A (left) and Case B (right) envelope Source: EnergyPlus

Above Comfort Belove Comfort Fig5.102 Number of hours out of comfort Source: EnergyPlus

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

ECE DURMAZ

During winter, only techno era scenario of envelope B and C stayed in the comfort band. As seen in column on the right side of the page, Case C overheated 18 hours more than Case B. On the other hand, envelope C had a much better winter performance and required heating 189 hours less than Case B. Therefore, natural ventilation integrated airtight buildings perform better for this orientation.

 





 



141

CASE 5.2: TECHNO ERA + 4.3

CHANGED INPUTS







DAY TIME OCCUPANCY: 80% -> 90%









LIGHTING LOAD: 7W/M2 -> 4W/M2









EQUIPMENT LOAD: 12W/M2-> 22W/M2









FRESH AIR REQUIREMENT: 1.03 ACH -> 1.16 ACH









































 



  



 



 

 

 

   

Fig5.104 Comparison of two future scenarios with different internal for Case C envelope (left) and result of typical winter days simulation Source: EnergyPlus

NATURAL VENTILATION PERIOD: MAY - OCTOBER Above Comfort Belove Comfort Fig5.105 Number of hours out of comfort Source: EnergyPlus

142

ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

5.3.3 WEST FACADE

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

COMPARISON OF THE LOADS & OPTIMIZATION The findings of the context study show a great similarity with east oriented offices, as expected. However, the vertical shading devices were not effective as horizontal foldable panel used for east facade, especially in airtight envelopes. Since, the east facing offices use the advantage occupancy pattern, operable solar protection systems should be assigned to west facade first if there is a limited budget. Additionally, the impact of a strong summer sun could be minimized by designing landscape according to passive principles. For instance, deciduous trees which act as â&#x20AC;&#x153;living awningsâ&#x20AC;? are in phase with the thermal year and gain/drop leaves according to outdoor temperature changes.

Figure5.106 shows that despite using adaptive comfort band and effective ventilation strategies, cooling necessity was still higher than the other facades. All in all, 86% reduction in cooling consumption was achieved with the application of passive measures.

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

28oC 20oC

30o







ECE DURMAZ



 

 

 





 

143

Heating Load Cooling Load

 

   

 

 

 















 

 













 

 











  







  











 

 

 























 



 







   







 













 











Fig5.106 Heating and cooling load consumption for Case A, B and C envelopes Source: OpenStudio & EnergyPlus







 

144

ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

5.3.4 NORTH FACADE CASE 1.1: BASE

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

1. CONTEXT As seen in Chapter 4: Context & Climate, the north facade does not receive much solar radiation, especially during the cold period. Therefore, the change in context did not create a significant difference for the north facing offices. In all cases, the temperatures remained below the comfort band (Fig5.108 left).

During summer, the operative temperatures reduced by around 1K (Fig5.108 right).

Compared to the other facades, this change was quite low since early morning and late afternoon sunlight is not strong. Hence, the context does not have a crucial impact on the thermal performance of the offices facing this orientation.



 



 









































































CASE 1.2: 1.1 + 30O OBSTRUCTION ANGLE

30o

 



 







































Fig5.108 Thermal analysis of 3 envelopes in a different context for typical winter (left) and summer (right) days Source: EnergyPlus

Above Comfort Belove Comfort Fig5.107 Number of hours out of comfort Source: EnergyPlus

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

ECE DURMAZ

145

2. SHADING STRATEGY According to the results of the daylight analysis, having shading devices drastically decreased the amount of useful daylight. Therefore, the “no shading” case was accepted for further thermal studies.

CASE 1.3: 1.1 + 50O OBSTRUCTION ANGLE

3. NIGHT SHUTTER The internal temperatures of an airtight building could be raised by 2.5K via the night shutters whereas this was around 1K for the leaky envelopes. The figure below shows that only Case3.1C stayed in the comfort band for typical winter days. To conclude, although implementation of night shutters helps to maintain winter comfort, the efficacy changes significantly with the envelope.



 

50o























CASE 3.1: 2.1 + NIGHT SHUTTER 













 





























Fig5.109 Effect of night shutters for typical winter days Source: EnergyPlus





NIGHT SHUTTERS: NOVEMBER - MID-APRIL Above Comfort Belove Comfort Fig5.110 Number of hours out of comfort Source: EnergyPlus

146

ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

5.3.4 NORTH FACADE

As seen in the figures below, the internal temperatures of no-ventilation cases (Case3.1) were similar to the ones in the south facade since shading was not considered for the north orientation.

CASE 4.1: 3.1 + 1 SIDED VENTILATION

In all cases, 1-sided ventilation (Case4.1) exceeded the comfort band threshold for a typical sunny summer day. Hence, cross ventilation and night time cooling should be introduced to compensate for the lack of shading.

4. NATURAL VENTILATION

  





 











































































CASE 4.2: 4.1 + CROSS VENTILATION

 





 





































Fig5.112 Comparison of different ventilation strategies on Case A (left) and Case B (right) envelope Source: EnergyPlus

Above Comfort Belove Comfort Fig5.111 Number of hours out of comfort Source: EnergyPlus

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

Cross ventilation and/or additional night time cooling strategies performed well, and Case4.2 and Case4.3 stayed in comfort for all three envelopes. The internal temperatures decreased with passive means of ventilation by 5K, 7K and 9K for Case A, B and C respectively. Overheating hours were reduced from 1406 to 117 for envelope C (Fig5.110, Fig5.115).

The operative temperatures of Case4.3C were within the limit of EN251 – Type II standard for 63% of the occupied hours.

















 

 





 





















 









 





 



 

 

CASE 4.3: 4.2 + NIGHT COOLING





 

147





 

ECE DURMAZ





 

















 



  

 













 









































Fig5.113 Comparison of different ventilation strategies on Case C envelope Source: EnergyPlus

Fig5.114 Percentage of occupied hours within comfort according to EN15251 Standard Catergory II Source: AA SED Spreadsheet

NATURAL VENTILATION PERIOD: MAY - OCTOBER Above Comfort Belove Comfort Fig5.115 Number of hours out of comfort Source: EnergyPlus

148

ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

5.3.4 NORTH FACADE CASE 5.1: ENERGY CONSCIOUS + 4.3

CHANGED INPUTS

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

5. FUTURE SCENARIO The techno era scenario of all cases suffered from overheating due to high internal gains and the outdoor temperatures exceeding comfort limits in a sunny summer day.

Low equipment gains provide an opportunity for the energy conscious scenario to keep the windows closed in a sunny afternoon (June, 13th). Therefore, operative temperature was kept 1 – 2K below the high outdoor temperature during the occupied hours. As seen in Fig5.166, the overheating hours of Case B and C were almost equal for the energy conscious scenario. However, well-sealed Case C envelope clearly performed better than Case B since it required heating for a less period of time. Hence, airtight envelopes should be considered for future energy conscious offices.

 



 





 

DAY TIME OCCUPANCY: 80% -> 90%



LIGHTING LOAD: 7W/M2 -> 4W/M2









EQUIPMENT LOAD: 12W/M2-> 6W/M2









FRESH AIR REQUIREMENT: 1.03 ACH -> 1.16 ACH



















































 







 





















Fig5.117 Comparison of two future scenarios with different internal gains on Case A (left) and Case B (right) envelope Source: EnergyPlus

Above Comfort Belove Comfort Fig5.116 Number of hours out of comfort Source: EnergyPlus

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

ECE DURMAZ

149

On the other hand, both Case B and C in techno era scenario performed well for the typical winter days (Fig5.188 right). It is known that cooling a space is harder than heating, and costs more. Therefore, the detailed envelope studies should be held for real life cases if a techno explosion scenario is expected.

CASE 5.2: TECHNO ERA + 4.3

 





 



CHANGED INPUTS







DAY TIME OCCUPANCY: 80% -> 90%









LIGHTING LOAD: 7W/M2 -> 4W/M2









EQUIPMENT LOAD: 12W/M2-> 22W/M2









FRESH AIR REQUIREMENT: 1.03 ACH -> 1.16 ACH









































 



  



 



 

 

 

   

Fig5.118 Comparison of two future scenarios with different internal for Case C envelope (left) and result of typical winter days simulation Source: EnergyPlus

NATURAL VENTILATION PERIOD: MAY - OCTOBER Above Comfort Belove Comfort Fig5.119 Number of hours out of comfort Source: EnergyPlus

150

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5.3.4 NORTH FACADE

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

COMPARISON OF THE LOADS & OPTIMIZATION Different than the other facades, the leaky Case A office required more heating than cooling in north orientation. As seen in the Figure5.120, heating consumption could not be reduced significantly even when night shutters were applied. Therefore, it is crucial to use airtight envelope to deal with low winter temperatures in Ankara.

The same figure also shows that although solar protection was not assigned, 86% reduction in cooling load was achieved through natural ventilation.

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

28oC 20oC

30o





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 

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

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 

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151

Heating Load Cooling Load

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Fig5.120 Heating and cooling load consumption for Case A, B and C envelopes Source: OpenStudio & EnergyPlus

 





6. OUTCOMES & DESIGN APPLICABILITY COMPARISON OF THE FINDINGS OUTCOMES DESIGN APPLICABILITY

ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

INS. LEVEL 1 Thermal insulation level of the building envelope which provides closer U values (overall heat transfer coefficient) to the limits defined in TS 825 national standard INS. LEVEL 2 Thermal insulation level of the building envelope which provides much lower U values than the limits of TS 825 national standard GLAZING The existing glazings are replaced with: SHGC = 0.44, U = 1.6, Tvis = 0.71 SHADING Aluminum fixed shading devices are installed horizontally on south facade and vertically on east and west façade LAMPS Incandecent Lamps (60 W) constituting 30% of the system are replaced with compact fluorescent lamps (12 W) LIGHTING C. Daylight responsive automatic lighting control is installed

Fig6.1 Inputs and factors used by Ganic and Yilmaz (top), details of retrofit packages applied to the office building (bottom) Source: After Ganic and Yilmaz, 2014

As seen in the figure below, the results of Case 3.1A showed a great similarity with Case 16A reported by Ganic and Yilmaz (2014). The second step was held for revealing the impact of an airtight envelope. In this case heating load requirement decreased by 62% (Case 3.1C). The primary load consumption reduced to 84 kWh/m2, at most, with the implementation of natural ventilation and rearrangement in thermostat set points (Case 4.3C). On the other hand, the best performing case in Ganic and Yilmaz’s study still required 119 KWh/m2.

When breakdown of the loads was analyzed, it was clear that overheating problem of a well-sealed envelope can be minimized with the application of natural ventilation.

Therefore, it is important to consider effective ventilation strategies for the offices during the design stage. Additionally, Figure6.2 shows that admission of lighting control system decreased artificial lighting load more than 50%. Hence, new designs should use means of technological developments to cut unnecessary energy consumption.

    



Chiller COP:1.5

It is important to compare findings with studies conducted by others since replication is a key element to generalise. Therefore, 3 south oriented office cases were compared with Ganic and Yilmaz’s study held for a virtual office building in Ankara (previously mentioned in the Chapter 2: Literature Review). The selected Case 16A from Ganic and Yilmaz’s work shows a retrofitted building with minimum insulation levels suggested

by TS 825 national standard. Considering the renovation packages explained in Figure6.1, Case 16A was compared with Case 3.1A. In order to have a fair comparison, 8 kWh/m2 “other mechanical load” was added to all cases in this study. Same national primary energy factors and chiller coefficient of performance (COP:1.5) were used while converting the results.





Heating Set Point: 21 C Cooling Set Point: 26oC o

6.1 COMPARISON OF THE FINDINGS



National Primary Energy Conversion Factors: 1 for natural gas 2.36 for electricity

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16



6.1 COMPARISON OF THE FINDINGS



154

     

 GANIC & YILMAZ, 2014 BASE +

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 GANIC & YILMAZ, 2014



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INS LEV.1 +

INS LEV.2 +

28oC 20oC

GLAZING + SHADING + LAMPS

GLAZING + SHADING + LAMPS + LIGHTING C.

 

 

Fig6.2 Comparison of primary energy consumption for the selected cases Source: After Ganic and Yilmaz, 2014

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

6.2 OUTCOMES Determining size and shape of a good performing building that ensures well-lit environments while balancing heat gain and heat loss might be complex. However, some general rules can help to enhance occupant comfort and minimize energy consumption during the design process. Therefore, analytic work was carried out to reveal potential savings that can be obtained through bioclimatic design.

Daylight quality of the working environment is quite crucial compared to the other typologies since most of the current offices in Ankara have not employed flexible working styles that provide adaptive opportunities such as; flexibility in working hours, dress code and work space selection. Regarding the daylight studies, orientation based shading device selection proved to be effective to reduce over illumination issues next to window pane. Additionally, it was found that the operable solar protection systems are necessary for the offices in Ankara since the number of sunny and overcast days are almost equal. Another finding of this study was that the passive zone depth shows variety depending on the orientation and shading device selection. Two sided office organization that reduces the contrast in the room, enables space depth to extend up to 10 m while providing sufficient level of natural daylight. 3-sided atrium can be used as a second source of daylight in order to minimize the heat loss through exposed facades. The daylight studies also show that glare has a direct relationship with the furniture layout. Therefore, a well-designed office space can eliminate glare without compromising the daylight level.

The thermal performance analysis demonstrated that the offices in Ankara can perform as free-running for the 72% of the occupied time with 92% reduction in cooling energy consumption. It was found that the impact of the neighbourhood buildings on the loss of winter solar gains are getting crucial, as the urban area becomes denser. South facade suffers more from this change in urban context since opposing constructions block low altitude sun and decrease winter passive gains without providing any benefit for summer. Controlling unwanted solar gains are important since they can exacerbate the internal gains from occupant, equipment and artificial lighting. Shading devices assigned according to orientation, reduced the cooling energy consumption significantly with a small amount of penalty on the heating loads. The results can be improved with the implementation of dynamic solar protection systems.

Night shutters help to enhance winter comfort in all cases. However, efficacy of the night shutters is directly related with the airtightness since leaky buildings loose heat through the envelope during winter nights.

In addition to providing sufficient natural light to the office spaces, an atrium can assist cross ventilation. The analytic work showed that 1-sided ventilation is not sufficient to maintain comfort in many cases. Hence, effective ventilation strategies should be taken into account during the design stage. Additionally, potential of night time cooling should be included for the new office buildings in Ankara since summer outdoor temperature could exceed the comfort level in the future.

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6.2 OUTCOMES

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6.3 DESIGN APPLICABILITY

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

6.3 DESIGN APPLICABILITY The next few pages offer guidelines for the applicability of a sustainable office building design in Ankara. The guidelines correspond to the future trends and climate change by adopting atrium as a socializing space and essential of ventilation, along with other passive strategies.

A layered structure can be used for concept and design stage: 1. BALCONY I EXTERNAL FRAME: Literature research indicated that facades should be considered as a buffer zone instead of a plane. Hence, the necessary space should be left for shading device installations. Operable shading devices working with smart systems help to adjust facade for sunny and overcast skies while limiting excessive solar gains. In the case of balcony, the space provides an opportunity to improve outdoor connections. Therefore, balcony serves both as a relaxing space and a solar protection for the facades requiring horizontal shading.

2. EXTERNAL ENVELOPE: The envelope should be designed to correspond different climatic conditions; external wall with low-u value and limited amount of glazing help to provide thermal comfort during winter. To eliminate the risk of overheating, adequate ventilation can be provided via atrium.

3. OFFICES: The maximum depth and possible layout of a 2-sided office space can be determined by considering the findings in analytic work. Orientation driven depth maximizes daylight availability in the office space and reduces artificial lighting loads.

This is the only zone occupied permanently. Therefore, mix mode ventilation can be applied.

4. INTERNAL WALL: WWR can be higher since this wall doesnâ&#x20AC;&#x2122;t have a direct relation with exterior. Additionally, using glazing with higher visible transmittance value help to get more daylight from atrium.

5. CIRCULATION AREA: It was found that 1.5m corridor depth works well with two sided offices. The depth can be extended where cellular offices are located. Therefore, this platform can serve as a socializing area.

6. ATRIUM I GALLERY SPACE: As mentioned before, atrium acts as huge chimney and expels hot air from atrium top. This functional space performs well for offices due to high internal gains. Additionally, adequate ventilation could be provided to deep plan spaces (exceeding passive zone depth) via cross vent + stack effect. Surrounded from 3 or 4 sides with offices, temporarily occupied atrium space does not require mechanical ventilation. From occupant perspective, the gallery space provides resting, social interaction and alternative working spaces. Atrium can help to provide visual connection between floors and add a certain vibe to a space by adding elements of visual interest.

1. BALCONY flexible dimensions

2. EXTERNAL ENVELOPE 3. OFFICES (MIXED MODE) 4. INTERNAL WALL 5. CIRCULATION 6. ATRIUM

Fig6.3 Concept diagram showing the design principle

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

ECE DURMAZ

DESIGN STEPS

1. Conceptual layered system

5. Determine the depth of the open offices according to the findings of the analytic work

2. Push the layers to the west to have a 3-sided atrium

6. Mixture of the cellular and open offices provides an opportunity to have deeper corridors / relaxing areas. Additionally, onesided spaces can be placed behind the core.

3. Place the vertical circulation core

7. Add solar protection devices to the all facades and atrium top

4. Set or eliminate the balcony layer with respect to the orientation

8. Use high-tech sustainability systems such as heat pump, solar panels etc.

Fig6.4 Figure showing the suggested design process

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PROPOSED OFFICE LAYOUT

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

SOLAR PROTECTION TRANSLUCENT BLADES UDI (100 - 2000 LUX): 78%

IN



UDI (100 - 2000 LUX)

IN

 



N

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UDI (100 - 2000 LUX): 77%

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

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T. HOR. FOLDABLE PANEL UDI (100 - 2000 LUX): 73%  

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 

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65o IN

      OUT

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NO SHADING UDI (100 - 2000 LUX): 71% OUT N

NORTH

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8M DEPTH Fig6.5 Performance matrix for different orientations

% 0

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DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

GLARE CONTROL

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DAYLIGHT FACTOR*

159

THERMAL PERFORMANCE**

SEP 21 I 12:00 OVERCAST SKY STATE I DGP: 0.31 FREE-RUNNING FOR IN

OUT

   

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OF THE OCCUPIED TIME

HEATING CONSUMPTION: 16 KWH/M2A

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72%

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3.7 KWH/M A 2

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IN

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HEATING CONSUMPTION: 22 KWH/M2A COOLING CONSUMPTION:

4.3 KWH/M A 2

SEP 21 I 14:00 OVERCAST SKY STATE I DGP: 0.43 FREE-RUNNING FOR

IN

57%

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6.9 KWH/M A 2

JUN 21 I 17:00 NO SHADING CASE I DGP: 0.27

FREE-RUNNING FOR

OUT

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63%

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4.5 KWH/M A 2

CD/M 0 2

200

400

600

800

1000

* Solar protection devices were kept in the overcast state

** Results for Case 4.3C with readjustments in thermostat set points

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ARCHITECTURAL ASSOCIATION SCHOOL OF ARCHITECTURE

SOUTH FACADE TRANSLUCENT BLADES

Fig6.6 Image of the south facing office under overcast sky Source: Lumion

SOUTH FACADE TRANSLUCENT BLADES

Fig6.7 Image of the south facing office under sunny sky. Although blades are tilted, daylight can still penetrate.

Source: Lumion

SOUTH FACADE SOLID BLADES

Fig6.8 In the case of solid material usage, daylight only comes from atrium.

Therefore, artificial lighting is required.

Source: Lumion

MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

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161

WEST FACADE VERTICAL SHADING

Fig6.9 Image of the west facing office under overcast sky Source: Lumion

WEST FACADE VERTICAL SHADING

65o Fig6.10 Image of the west facing office. Due to set back distance, direct light does not fall on the working plane.

Source: Lumion

EAST FACADE HOR. FOLDABLE PANEL

Fig6.11 Image of the east facing office. Although foldable panel is closed, daylight can still penetrate.

Source: Lumion

7. CONCLUSIONS

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Fig7.1 Exterior view of a possible south facade design Source: Lumion

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

CONCLUSIONS The implementation of passive design measures can have a significant impact on office buildings in terms of providing occupant comfort and reducing cooling consumption.

Today, many architects and contractors only rely on expensive high tech engineering systems to minimize energy usage and try to integrate them into the building. However, throughout this dissertation, it was possible to understand that using passive strategies has the most vital effect. Therefore, in order to achieve a good performing building, bioclimatic strategies should be prioritized during the design process. The design must be specific to its context and climate, and a wide range of aspects such as the orientation, building shape and layout, airtightness of the envelope, internal gains and changing trends must be considered. Some conflicts between winter and summer performances are most likely to be found; however, the result is complex, and it is necessary to make prioritisation in such cases.

As seen in the built precedents and analytic work chapters, the atrium typology provides better results for natural ventilation by exhausting warm air through stack effect, and creating a pleasant working and resting environment for the next-generation occupants. The studies show that occupant comfort can be provided for 72% of the time through the application of stack ventilation and night time cooling besides other passive strategies. Apart from the qualitative benefits, cooling energy consumption can be reduced up to 92% with a small amount of penalty on heating loads. Cooling down a building is more expensive and requires more primary energy usage than heating, therefore, the results are promising. Moreover, it is worth stressing that the benefits of passive measures, especially when they are related with the admission of natural ventilation, mainly depend on the acceptance of the adaptive thermal comfort standards by the architects, contractors, engineers and clients. Therefore, achieving an energy sufficient sustainable building requires more awareness and research to change the existing perception. Government authorities should also be involved in this multidisciplinary approach by providing incentives to the successful cases and funding for further sustainability research.

Ultimately, although this dissertation aimed to give guidelines about a range of aspects related with the passive designs in office buildings in Ankara, it is important to highlight that some external factors such as urban noise and air pollution which can significantly affect the application of ventilation strategies were not taken into consideration. Additionally, the impact of low tech and high tech systems to minimize energy consumption and building automation systems can still be explored in depth.

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8. REFERENCES

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REFERENCES Alonso R., Dias A., Durmaz, E., & Eid, P. (2015). Refurbishing the city: QUBE HOK office. Architectural Association School of Architecture, London, UK. Altensis Energy Management. Eser yesil binasi (Eser green building). (2010). Retrieved July 25, 2016. from http://www.altensis.com (in Turkish) Ander, G. D. (2003). Daylighting performance and design (2nd ed.).

Arnold, D. (1999). Air Conditioning in Office Buildings after World War II. ASHRAE Journal, July, 1999. p.

33-41.

Baker N. V. (2007). High performance daylighting â&#x20AC;&#x201C; light and shade. Revival Technical Monograph 4 www. revival-eu.net Baker, N. V., Fanchiotti, A., & Steemers, K. (Eds.). (1993). Daylighting in architecture: A European reference book (p. 5.1). London: Published for the Commission by James & James.

Baker, N. V., Steemers, K. (2000). Energy and environment in architecture: A technical design guide. New York: E & FN Spon.

Bedford, M., Harris, R., King, A., & Hawkeswood, A. (2013). Occupier density study 2013. British Council for Offices.

Bhar, R. (2016). Towards nearly zero energy buildings in Germany. Cologne University of Applied Sciences.

Retrieved May 25, 2016, from http://vae.ahk.de Boubekri, M. (2014). Strategies and systems performance. In Daylighting design: Planning strategies and best practice solutions (pp. 63-65). Berlin: Birkhäuser Verlag GmbH. Bradshaw, V. (2006). The building environment: Active and passive control systems (3rd ed.). Hoboken, NJ: Wiley.

Brown, G., & DeKay, M. (2014). Detailed design strategies. In Sun, wind & light: Architectural design strategies. Retrieved from https://books.google.co.uk Butcher, K., & Craig, B. (Eds.). (2016). CIBSE guide A (8th ed.). London: The Chartered Institution of Building Services and Engineers.

Cakici, F. Z. (2013). The development of a building energy performance evaluation program (EnAd) for architectural design process. Middle East Technical University, Ankara, Turkey.

Cakmanus, I. (2007, January 4). Renovation of existing office buildings in regard to energy economy: An example from Ankara, Turkey. Building and Environment 42, 1348-1357. http://dx.doi.org/10.1016/j. buildenv.2005.11.007 Cakmanus, I., Kunar, A., Toprak G., Gulbeden, A. (2010). A case study in Ankara for sustainable office buildings, REHVA 10. Clima Congress- Clima 2010.

Chauvel, P., Collins, J. B., Dogniaux, R., & Longmore, J. (1982). Glare from windows: Current views of the problem (Vol. 1). Lighting Research and Technology.

Colvin, J., Tobler, N., & Anderson, J. (2004) Productivity and multi-screen computer displays (Vol. 2), Rocky Mountain Communication Review.

Crisinel, M., Eekhout, M., Haldimann, M., & Visser, R. (Eds.). (2007). Glass & Interactive Building Envelopes (Vol. 1, Research in Architectural Engineering Series). Netherlands: IOS Press; pp. 41 Cukierski, G., & Rector, R. (2006). Energy saving window treatments final report. Ithaca, NY: Cornell University Department of Design & Environmental Analysis.

Duarte-Roa, C. (2013). Revealing occupancy patterns in office buildings through the use of sensor data providing whole building energy simulation. University of Idaho, Ankara, United States of America.

Durmaz, E. (2016). Daylight and thermal performance of office buildings in Ankara. Architectural Association School of Architecture, London, UK. Enerji Verimliligi Dernegi (Association for Energy Efficiency). (2015). Konutlarda verimlilik (Energy efficiency in residential buildings). Retrieved May 26, 2016, from http://www.enver.org.tr (in Turkish) Frank, T., Guttinger, H., & Van Velsen, S. (2007). Thermal comfort measurements in a hybrid ventilated office room. Proceedings of Clima 2007 WellBeing Indoors.

Ganic, N., & Yilmaz, A. Z. (2014, March 13). Adaptation of the cost optimal level calculation method of Directive 2010/31/EU considering the influence of Turkish national factors. Applied Energy 123, 94-107. http://dx.doi.org/10.1016/j.apenergy.2014.02.045 Heschong, L. (2003). Windows and Offices: A Study of Office Worker Performance and the Indoor Environment (pp. 138-139, Tech.). California: California Energy Commision.

Ho, D. (1996). Climatic responsive atrium design in Europe. Architectural research quarterly (Vol. 1).

Cambridge: Cambridge University Press.

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Ilmonen, L. (2015). Development of a quality assurance tool to minimize performance gap in nZEBs (Unpublished master’s thesis). Helsinki Metropolia University of Applied Sciences.

International Energy Agency. (2006). Key world energy statistics.: IEA Press.

Iyengar, K. (2015). Sustainable architectural design: An overview. Routledge.

Johnston, J., Counsell, J., & Strachan, P. A. (2011, September 06-07). Trends in office internal gains and the impact on space heating and cooling. CIBSE Technical Symposium. Leicester, UK. Lehmann, B., Guttinger, H., Dorer, V., Velsen, S. V., Thiemann, A., Frank, T., ... Beerle, D. (2009). Energiedetailbilanz des Eawag Forum Chriesbach (Detailed Energy Assessment of Eawag Forum Chriesbach).

Retrieved from http://www.eawag.ch (in German) Liebel, B., Brodrick, J. (2005, October). Lighting and Standard 90.1. ASHRAE Journal,47(10). Retrieved June 30, 2016.

Loudon, A. G. (1968). Summertime temperatures in buildings without air-conditioning. Garston, England: Building Research Station.

Markus, T.A. (1967). The significance of sunshine and view for office workers. Proceedings of the CIE Conference on Sunlight in Buildings (pp. 59–93). Rotterdam: Bouwcentrum International.

Ne’eman, E. & Hopkinson, R.G. (1970). Critical minimum acceptable window size: A study of window design and provision of view. (pp17–27). Lighting Research and Technology.

Oldfield, P., Trabucco, D., & Wood, A. (2008). Five energy generations of tall buildings: A historical analysis of energy consumption in high rise buildings. Council on Tall Buildings and Urban Habitat. The Journal of Architecture, 14(5), 591-613.

Osterhaus, W. K. E. (2001). Discomfort glare from daylight in computer offices: How much do we really know? In LUX Europa 2001, 9th European Lighting Conference (pp. 448-456). Reykjavík.

Osterhaus, W. K. E. (1993). Office Lighting: A review of 80 years of standards and recommendations. proceedings of the IEEE Industry Applications Society Annual Meeting, October 2-8, 1993, Toronto, Canada.

Prowler, D. (2014, December 18). Sun control and shading devices. Retrieved April 15, 2016, from https:// www.wbdg.org/resources/suncontrol.php Resmi Gazete (Turkish National Journal). (2012, February 25). Enerji verimliligi strateji belgesi 2012-2023 (Energy efficiency strategy certificate 2012-2023). (28215). Retrieved from http://epsder.org.tr (in Turkish) Robinson, A. Selkowitz, S. (Eds.). (2013). Tips for daylighting with windows. Berkeley, CA: U.S. Department of Energy.

Ruck, N. (2000). Daylighting systems. In Ø. Aschehoug, J. Christoffersen, R. Jakobiak, K. Johnsen, E. Lee, N. Ruck, et al. (Eds.), Daylight in buildings: A source book on daylighting systems and components (pp. 4-16 4-21). Berkeley, California: Lawrence Berkeley National Laboratory.

Ruffles, P. (2005). Detailed room design information. In Lighting guide 7: Office lighting (2nd ed.). London: The Society of Light and Lighting.

Sustainable by design 2050. (2011). Retrieved June 25, 2016, from http://www.sbd2050.org TEDAS (Turkish Electricity Distribution Co.). (2014). Kullanici gruplarina gore elektrik tuketimi (Electricity usage according to user groups). Retrieved June 12, 2016, from http://www.tedas.gov.tr (in Turkish) TEIAS (Turkish Electricity Transmission Company). (2015). Electricity generation & transmission statistics of Turkey. Retrieved September 12, 2016, from http://www.teias.gov.tr The Health and Safety Executive: Working with employers. (1994). Sudbury: HSE Books.

Turk Standartlari Enstitusu (Turkish Standards Institution). (2008). Binalarda isi yalitim kurallari (Thermal insulation requirements for buildings), TS 825. Ankara, TSE (in Turkish).

TurkStat (Turkish Statistical Institute). (2014). Building permits statistics. Retrieved August 25, 2016, from http://www.turkstat.gov.tr (in Turkish).

Ugursal, A. (2003). Integration of natural ventilation to office building typology in the Ankara context: A case study. Middle East Technical University, Ankara, Turkey.

Verderber, R. R., & Rubinstein, F. (1982, September). Lighting controls: Survey of market potential. Energy & Environment Division.

Vogele, R. (Ed.). (2009, January). “Etrium” building in Cologne. Objective, 4-5.

Wentz, D. (2007). Research center in Switzerland. Retrieved May 15, 2016, from www.holcimfoundation.org Wilkins, C. K., & Hosni, M. H. (2011, May). Plug Load Design Factors. ASHRAE Journal. Retrieved June 30, 2016.

Wood, A., & Salib, R. (2013). Guide to natural ventilation in high rise office buildings. USA: Sheridan Books

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9. APPENDICES

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9.1 LITERATURE REVIEW

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Table9.1Recommended u-values from different sources 







 































 

 















                     





                     





Fig9.1 Daily lighting demand profile for fluorescent tube (current case) and white LED (future scenario) Source: After Johnston et al., 2011









Fig9.2 Typical features of Generation 5.1 and 5.2 offices

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

A. 8 FLOORS

B. 15 FLOORS

C. 22 FLOORS

























Fig9.3 Hypothetical context scenarios and three possible urban canyon scenarios

CASE S: JUNE 1ST 00:00, AUGUST 31ST 24:00 CASE W: DECEMBER 1ST 00:00, FEBRUARY 28TH 24:00

SOUTH FACADE

EAST FACADE

WEST FACADE

NORTH FACADE

Fig9.4 Solar radiation studies for the hypothetical context scenarios Source: Ladybug + Honeybee

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9.3 ANALYTIC WORK CASE 1: OVERHANG MEAN ILLUMINANCE: 510 LUX

SOUTH I OVERCAST I SEP 21 I 12:00

N

54o

CASE 3: HORIZONTAL BLADES MID - PART 30o TILTED W: 55CM I R: 0.85 MEAN ILLUMINANCE: 313 LUX

CASE 1: NO SHADING MEAN ILLUMINANCE: 681 LUX

EAST I OVERCAST I SEP 21 I 10:00

N

CASE 3: VERTICAL SHADING 42O TILTED I W: 145CM I VT: 0.15 MEAN ILLUMINANCE: 380 LUX

42o Fig9.5 Illuminance levels for south and east facades Source: Ladybug + Honeybee

LUX 0

150

300

450

600

750

900

1050

1200

1350

>1500

DAYLIGHT AND THERMAL PERFORMANCE OF OFFICE BUILDINGS IN ANKARA

175

9.3 ANALYTIC WORK

N

SOUTH I SUNNY I SEP 21 I 12:00

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CASE 1: OVERHANG MEAN ILLUMINANCE: 1630 LUX

54o

CASE 3: HORIZONTAL BLADES 65o TILTED W: 55CM I R: 0.85 MEAN ILLUMINANCE: 282 LUX

EAST I SUNNY I SEP 21 I 10:00

LUX 0

150

300

450

600

750

900

CASE 1: NO SHADING MEAN ILLUMINANCE: 4760 LUX

N

1050

1200

1350

>1500

Fig9.6 Illuminance levels for south and east facades Source: Ladybug + Honeybee

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9.3 ANALYTIC WORK CASE 2: TRAN. FOLDABLE PANEL FOLDED I W: 145CM I VT: 0.15 MEAN ILLUMINANCE: 520 LUX

WEST I OVERCAST I SEP 21 I 14:00

N

CASE 4: VERTICAL SHADING OPEN I W: 145CM I R: 0.85 MEAN ILLUMINANCE: 507 LUX

NORTH I OVERCAST I JUN 21 I 17:00

N

CASE 2: TRAN. FOLDABLE PANEL FOLDED I W:145CM I VT: 0.25 MEAN ILLUMINANCE: 329 LUX

CASE 3: TRAN. VERT. SHADING OPEN I W:190CM I VT: 0.25 MEAN ILLUMINANCE: 303 LUX

Fig9.7 Illuminance levels for west and north facades Source: Ladybug + Honeybee

LUX 0

150

300

450

600

750

900

1050

1200

1350

>1500

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9.3 ANALYTIC WORK WEST I SUNNY I SEP 21 I 14:00

CASE 2: TRAN. FOLDABLE PANEL CLOSED I W: 145CM I VT: 0.15 MEAN ILLUMINANCE: 690 LUX

N

CASE 4: VERTICAL SHADING 65o TILTED I W: 145CM I R: 0.85 MEAN ILLUMINANCE: 434 LUX

65o

N

NORTH I SUNNY I JUN 21 I 17:00

CASE 2: TRAN. FOLDABLE PANEL HALF FOLDED I VT: 0.25 MEAN ILLUMINANCE: 593 LUX

CASE 3: TRAN. VERT. SHADING 25O TILTED I W:190CM I VT: 0.25 MEAN ILLUMINANCE: 598 LUX

25o LUX 0

150

300

450

600

750

900

1050

1200

1350

>1500

Fig9.8 Illuminance levels for west and north facades Source: Ladybug + Honeybee

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9.3 ANALYTIC WORK

TRANSLUCENT BLADES MID - PART 30o TILTED W: 55CM I VT: 0.15 UDI (100 - 2000 LUX): 78% MEAN DA (300 LUX): 83%

N

SOUTH I OVERCAST STATE I DA (300 LUX)

EAST I OVERCAST STATE I DA (300 LUX)

N

HORIZONTAL FOLDABLE PANEL FOLDED I W: 190CM I VT: 0.15 UDI (100 - 2000 LUX): 73% MEAN DA (300 LUX): 71%

Fig9.9 Daylight Autonomy (300 lux) for south and east facades Source: Ladybug + Honeybee

%

0

10

20

30

40

50

60

70

80

90

100

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9.3 ANALYTIC WORK N

SOUTH I SUNNY STATE I DA (300 LUX)

TRANSLUCENT BLADES 85o TILTED W: 55CM I VT: 0.15 UDI (100 - 2000 LUX): 77% MEAN DA (300 LUX): 46%

EAST I SUNNY STATE I DA (300 LUX)

N

HORIZONTAL FOLDABLE PANEL CLOSED I VT: 0.15 UDI (100 - 2000 LUX): 67% MEAN DA (300 LUX): 39%

%

0

10

20

30

40

50

60

70

80

90

100

Fig9.10 Daylight Autonomy (300 lux) for south and east facades Source: Ladybug + Honeybee

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9.3 ANALYTIC WORK

WEST I OVERCAST STATE I DA (300 LUX)

N

TRANSLUCENT SHADING OPEN I W: 145CM I VT: 0.15 UDI (100 - 2000 LUX): 75% MEAN DA (300 LUX): 68%

N

NORTH I NO SHADING I DA (300 LUX) NO SHADING UDI (100 - 2000 LUX): 71% MEAN DA (300 LUX): 85%

Fig9.11 Daylight Autonomy (300 lux) for south and east facades Source: Ladybug + Honeybee

%

0

10

20

30

40

50

60

70

80

90

100

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9.3 ANALYTIC WORK

WEST I SUNNY STATE I DA (300 LUX)

N

TRANSLUCENT SHADING 65o TILTED I W: 145CM I VT: 0.15 UDI (100 - 2000 LUX): 74% MEAN DA (300 LUX): 52%

65o

%

0

10

20

30

40

50

60

70

80

90

100

Fig9.12 Daylight Autonomy (300 lux) for south and east facades Source: Ladybug + Honeybee

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MSC SUSTAINABLE ENVIRONMENTAL DESIGN 2015 I 16

SOUTH

EAST

WEST

NORTH

Fig9.13 Thermal simulation models for different orientations Source: SketchUp & OpenStudio

9.4 DESIGN APPLICABILITY  

 

   

 

  

Fig9.14 Comparison of conceptual atrium sections with Forum Chriesbach