Varunya Yoon Jarunyaroj | AA March Sed Research Paper [Term 1]

AA SED Architectural Association School of Architecture Graduate School : MSc + MArch Sustainable Environmental Design 2015-2016

TERM 1 RESEARCH PAPER

ESTABLISHING FREE-RUNNING PERIODS IN EXISTING OFFICE BUILDINGS IN BANGKOK

VARUNYA JARUNYAROJ January 2016


Authorship Declaration Form

AA SED

ARCHITECTURAL ASSOCIATION GRADUATE SCHOOL

PROGRAMME:

MSc + MArch SUSTAINABLE ENVIRONMENTAL DESIGN 2015 - 16

SUBMISSION

RESEARCH PAPER 1

TITLE

ESTABLISHING FREE-RUNNING PERIOD IN EXISTING OFFICE BUILDINGS IN BANGKOK

NUMBER OF WORDS (excluding footnotes and references)

3,398

TITLE

ESTABLISHING FREE-RUNNING PERIODS IN EXISTING OFFICE BUILDINGS IN BANGKOK

STUDENT NAME:

Varunya Jarunyaroj

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that the contents of this document are entirely my own work and that any quotation or paraphrase from the published or unpublished work of others is duly acknowledged.”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: 11 January 2016

TABLE OF CONTENT ABSTRACT & INTRODUCTION Abstract

1

1. Introduction

1

2. Methodologies

1

MAIN BODY 3. Bangkok Thermal Comfort Band

2

4. Free Running Strategies

3

4.1 Controlling Heat Gain

3

4.1.1 Solar Control

3

4.1.2 Improving Building Envelope Performance

5

4.1.3 Users’ Behaviour

5

4.2 Passive Cooling Natural Ventilation

5

5. Study Model Analysis

6

CONCLUSION 6. Conclusion

10

AA SED Architectural Association School of Architecture MSc + MArch Sustainable Environmental Design 2015-16 January 2016 Term 1 Research Paper

_________________________________________________________________

ESTABLISHING FREE-RUNNING PERIODS IN EXISTING OFFICE BUILDINGS IN BANGKOK Varunya Jarunyaroj AA SED Sustainable Environmental Design Programme, Architectural Association School of Architecture Graduate School, London United Kingdom, MSc + MArch Sustainable Environmental Design 2015-16

_________________________________________________________________ ABSTRACT The study aimed to archive free-running methodologies and periods for existing office buildings in Bangkok using heat gain control and natural ventilation strategies. The research was done using mainly calculations and soft computation methods to test the typical office space study model base on the standard of comfort band available.

The result from the analysis indicate that without a major change of the building element, the existing office spaces or buildings in Bangkok are clearly implausible to be completely free-running for a long period. However, the freerunning strategies might be applied in order to reduce cooling load or archive a short daily free-running period.

1. INTRODUCTION

office buildings’ cooling strategies and apply the strategies to reveal a practicable free-running period for retrofitting existing office buildings.

The possibility that Bangkok office buildings or office spaces could periodically be free-running is promising in Winter season as well as Rainy season when the temperature is approximately 3-5 °C lower than Summer. Conversely, office buildings in Bangkok are implausible to be free-running in Summer when the outdoor temperature is considerably high.

Thailand is situated in Southeast Asia in the tropical climate zone close to the equator. Bangkok which is a capital of Thailand located on flat geometry approximately 4 metres above sea level and precisely at latitude 13 44’ N and longitude 100 34’ E. Being in close range of the equator, Bangkok generally gains high solar radiation with approximately average of 11 hours of daylight per day throughout the year and annual average outdoor temperature of 28°C. A year in Thailand is divided into 3 seasons; Summer between mid-February to mid-May follows by Rainy season from mid-May until mid-October and Winter starts in mid-October stretching to mid February.

Due to the hot and humid climate of Thailand with all year high solar radiation, the cooling airconditioning has become a common solution to control indoor condition. For typical office buildings in Bangkok, air-conditioners would be running all day in order to cool down the indoor temperature which is affected by high outdoor temperature, solar radiation, and high internal heat gain from occupants and appliances. However, in mild period when the outdoor temperature are cooler, office buildings still use airconditioners the same way as in hot period. Majority of office buildings in Bangkok, even though, were designed to be air-conditioned, but with suitable strategies, periods of complete free-running in office building in tropical climate zone, might be archivable.

This research paper tended to pursue tropical climate-

2. METHODOLOGIES The methodology of this research involved calculation, a study of literatures and soft-computation.

The first part of the research would be to measure environmental factors and general users’ behaviour in order to define comfort band range. The suitable cooling strategies were next designated using guidelines and recommendation from researches and publications.

The Last part of the research engaged establishing and analysing typical Bangkok office space study model using determined cooling strategies in order to gain legitimate result and conclusion of Bangkok existing office buildings freerunning performance.

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3. BANGKOK THERMAL COMFORT BAND

maximum and 28 °C - 34.2 °C in natural ventilated building. Busch suggested that Thai office workers are accustomed to warm climate which make the comfort zone range to be between 22 °C to 30.5 °C while the neutral temperature was at 25 °C. Although the Winter season temperature is lower and within the comfort band studied by Jitkajornwanich(1998) and Busch(1995) (Max Avg To = 30.5 Avg To = 26.5 Min Avg To =22.25), the daytime temperature could still be considered uncomfortable by occupants because the comfort zone is not precise criterion but just reference. By this reason, adaptive opportunity of the occupants to turn on and off airconditioners and control different building elements in order to improve indoor condition is also a huge factor.

Consequently, the adaptive opportunity could create positive or negative impacts so educate and including persuasive measure in the building design is undeniably crucial.

Similar to all modernising and developing city, Bangkok has dotted itself with high-rise commercial and residential building. Despite the fact that Bangkok is rather small compare to the others cities of Thailand, 23% of Thai overall population reside in Bangkok which consequently unsurprisingly leaded to the vertical growth of the city. Office building in Bangkok are vary in typologies from modified detached house to middle-rise and high-rise building which are majority; however, as mentioned, they are mostly air-conditioned. In typical air-conditioned building, the occupant would wear cloth code depend on how formal the office environment are; in formal office the occupant would wear 1.0 clo and in informal office the workers might wear 0.5 clo (Busch,1995).

BANGKOK 40

35

30

Fig. 1 Sathorn District, Bangkok

25

Most of the high-rise office building are grouping in the city central area like Silom or Sathorn (see Fig. 1). Typical office building would have airconditioners running all day aiming to archive the internal temperature of 25 °C which are generally believed to be practical internal temperature while the outside temperature might go up to 39 °C which means that the occupants would face a sudden extreme temperature change when leaving and entering the building. This situation does not only has an impact on the occupant but it also create an urban heat islands.

As studied by Taweekun and Tantiwichien (2013), Thai people’s thermal comfort zone range is wider than ASHRAE comfort zone due to hight relative humidity and the fact that people can adapt to the wider temperature range; the thermal comfort zone suggested by Taweekun and Tantiwichien is effective temperature of 24°C - 27 °C at 50-70% relative humidity and 0.2 m/s air velocity.

Furthermore, Jitkhajornwanich (1998)’s field study indicated that the internal and acceptable temperatures in office space in Bangkok were between 25.5 °C and 31.5 °C with Neutral temperature and 27.1 °C and preferable temperature at 26.7 °C. The study by Busch in 1995 which subject informal and formal office including the natural ventilated and air conditioned office building shown that the internal temperature in Bangkok office building varied from 19.5 °C-31 °C in air-conditioned buildings to a

20

AVERAGE WIND SPEED [m/s] AVERAGE DAILY DIFFUSE HORIZONTAL SOLAR RADIATION [kWh/m²] AVERAGE DAILY DIRECT HORIZONTAL SOLAR RADIATION [kWh/m²]

15

Comfort band limit [°C] AVERAGE MONTHLY MEAN TEMPERATURE [°C] AVERAGE MONTHLY MAXIMUM TEMPERATURE [°C] AVERAGE MONTHLY MIMIMUM TEMPERATURE [°C]

10

5

DECEMBER

NOVEMBER

OCTOBER

SEPTEMBER

AUGUST

JULY

JUNE

MAY

APRIL

MARCH

FEBRUARY

JANUARY

0

Fig. 2 Bangkok Comfort Band Analysis

The calculation of adaptive comfort band (see Fig. 2) using Climate Comfort worksheet by Brunelli (2015) specified the coherent comfort band range with the studies by Jitkhajornwanich(1998) and Busch (1995). The range of comfort band in Table 1 show that the differences of monthly average comfort band between each month are within 1.5 K.

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Table 1 Monthly Bangkok Comfort Band Analysis Average Average Average Comfort Comfort Monthly Monthly Monthly Band Band Max Min Upper Lower Month Tempera ture Tempera Tempera Limit Limit ture ture JAN

26.9 °C

32.3 °C

21.7 °C

30.7 °C

24.7 °C

FEB

28.0 °C

33.1 °C

23.7 °C

30.9 °C

24.9 °C

MAR

29.3 °C

34.4 °C

24.8 °C

31.3 °C

25.3 °C

APR

30.6 °C

35.1 °C

27.0 °C

31.8 °C

25.8 °C

MAY

29.9 °C

34.4 °C

26.3 °C

31.8 °C

25.8 °C

JUN

29.7 °C

33.3 °C

26.9 °C

31.6 °C

25.6 °C

JUL

29.0 °C

32.8 °C

26.0 °C

31.4 °C

25.4 °C

AUG

28.3 °C

32.1 °C

25.4 °C

31.2 °C

25.2 °C

SEP

28.2 °C

32.5 °C

25.3 °C

31.1 °C

25.1 °C

OCT

28.0 °C

31.2 °C

25.6 °C

31.1 °C

25.1 °C

NOV

27.7 °C

31.9 °C

24.2 °C

31.0 °C

25.0 °C

DEC

26.4 °C

31.2 °C

22.1 °C

30.6 °C

24.6 °C

4. FREE-RUNNING COOLING STRATEGIES According to Sustainable low energy cooling: an overview (Parsloe 2005),in term of energy use, cost, accuracy, and operating risks; the two most preferable cooling strategies are first reducing unnecessary heat gain follow by adopting passive cooling solutions which are systems that could operated without mechanical system.

Fig. 3 gives information regarding the trends of Bangkok daytime temperature in each month which starts constantly rising around 8AM - 9AM until reach the peak in afternoon period between 1PM - 4PM before starting to drop. The graph also indicates that the outdoor temperature gap between morning and afternoon periods is considerably wide. This wide gap however tend to be higher than the upper limit of the comfort band. Additionally, with the high heat gain, the temperature indoor would be higher than the outside which suggest that the heating strategies are unnecessary in office building in Bangkok while the cooling strategies is otherwise highly fundamental.

Fig. 4 Model for moderate typical office space

The study model of typical moderate size office in Bangkok was used in order to study the effect of the cooling strategies. According to Jones’s Metric Handbook (2008), the area requirement per person in typical office space is 9.3 m2. which leads the model space for moderate size office of 30 workers to be 279 m2 .

4.1 CONTROLLING HEAT GAIN The first methodologies to deal with heat is to control heat gain from both external and internal environment. This method is essential because it has high energy saving potential, generally low in cost, and has low design and operating risks compare to the others methods.The external heat gain could be mainly reduced by applying solar control strategies and improving building envelope. While the internal heat gain could be reduced by using less energy consumption appliances and electronic device as well as using scheduled controlling system; however, the procedures are difficult to control.

A V E R A G E D A Y TI M E H O U RL Y T E M P E R A T UR E January

February

March

April

May

June

July

August

September

October

November

December

36.0 °C 34.0 °C 32.0 °C 30.0 °C 28.0 °C

4.1.1 Solar Control Because the solar heat gain is one of the main heat gain issue in Bangkok, the solar control should be considered wisely as a top solution. Adding shading devices would be obviously a crucial part of resolution. The shading device could be permanently installed without operative measure in some case or could be operable in relation with seasonal change.

The overhang was chosen as it is a simple form of shading devices with could be adapt into operable or fixed devices and can be made solid or opaque while still allows natural ventilation.

26.0 °C 24.0 °C 22.0 °C 20.0 °C

Fig. 3 Bangkok Average Daytime Hourly Temperature

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The following diagrams (Fig. 6 - Fig. 9) show how much kWh/m2. of solar radiation on vertical surface a 2-metre overhangs would help reducing on windows facing different directions.

The diagrams clearly show less fluctuated trends of shaded glazing than the unshaded. This pinpoints that the overhang or the others shading devices would not only reduce the amount of radiation transmitted and absorbed into the space; it also help control and maintain level. The more stable of the solar radiation level, the easier it is to control and maintain indoor condition throughout the year.

To be more precise, the levels of solar radiation on the vertical surface with shading device are maintained at approximately 0.4-0.7 kWh/m2. if the glazings are on the North side and 0.5- 1.0 kWh/ m2 if facing the others directions.

Fig. 5 Overhang Shading Device

By adding shading devices, for example, 2 metres overhang on all the glazing (see Fig. 5) the solar radiation on the glazing would be reduced remarkably as shown in Table 2 and 3.

S O L A R R A D I A T I O N O N V E RT I C A L S U R F A CE (A V E R A G E C U M D A I L Y) (K WH / M2) Without Shading Device North Glazing

Table 2 Solar Radiation on Vertical Surface (kWh/m2)

With Shading Device (2m. overhang or equivalent) North Glazing

Without Shading Device Month

North Glazing

West Glazing

South Glazing

2.00

East Glazing

JAN

0.66

1.81

3.47

1.82

FEB

0.76

1.94

2.97

2.02

MAR

0.81

2.16

2.15

2.20

APR

1.17

1.90

1.31

2.09

MAY

1.54

1.74

1.07

1.83

JUN

1.78

1.72

0.99

1.81

JUL

1.63

1.74

1.01

1.62

AUG

1.26

1.57

1.15

1.61

SEP

1.07

1.76

1.62

1.75

OCT

0.89

1.64

2.19

1.78

NOV

0.69

1.77

3.22

1.89

DEC

0.62

1.74

3.63

1.81

1.80 1.60 1.40 1.20 1.00 0.80 0.60 0.40 0.20 0.00 JAN

West Glazing

South Glazing

0.43

0.89

0.99

0.89

FEB

0.47

0.96

0.85

0.98

MAR

0.48

0.99

0.64

1.02

APR

0.58

0.85

0.60

0.96

MAY

0.66

0.78

0.57

0.88

JUN

0.70

0.78

0.54

0.85

JUL

0.68

0.80

0.55

0.80

AUG

0.62

0.75

0.59

0.78

SEP

0.58

0.84

0.70

0.88

OCT

0.52

0.80

0.81

0.93

NOV

0.44

0.87

0.94

1.00

DEC

0.40

0.81

1.03

0.91

JUN JULY AUG

SEP

OCT NOV

DEC

Without Shading Device West Glazing With Shading Device (2m. overhang or equivalent) West Glazing 2.50

East Glazing

JAN

APR MAY

S O L A R R A D I A T I O N O N V E RT I C A L S U R F A CE (A V E R A G E C U M D A I L Y) (K WH / M2)

With Shading Device (2m. overhang or equivalent) North Glazing

MAR

Fig. 6 The comparison of solar radiation on vertical surface between with and without shading device situation (North)

Table 3 Solar Radiation on Vertical Surface with shading device (KWh/m2)

Month

FEB

2.00

1.50

1.00

0.50

0.00 JAN

FEB

MAR

APR MAY

JUN JULY AUG

SEP

OCT NOV

DEC

Fig. 7 The comparison of solar radiation on vertical surface between with and without shading device situation (West)

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For existing building, the modification of the overall building envelope could be challenging and might not be practical in term of cost and structure; however, to the alteration of windows design is probably feasible. By changing frames and glazing type and arrangement, for example, replacing single glazing windows with the ones using tripling glazing would lower the glazing U-Values.

With the alteration of windows design or building element, the air leakage is one of the most important factors that should be carefully considered as the building also unavoidably uses air-conditioning system.

S O L A R R A D I A T I O N O N V E RT I C A L S U R F A CE (A V E R A G E C U M D A I L Y) (K WH / M2) Without Shading Device South Glazing With Shading Device (2m. overhang or equivalent) South Glazing 4.00 3.50 3.00 2.50 2.00 1.50 1.00

4.1.3 User Behaviour A research (Brager et all 2001) found that people living in air-conditioned space would develop high expectation for cool temperatures and could be critical when the indoor temperature differ from the middle of the comfort zone which they expect. This indicate that user misbehaviour or adaptive opportunity might have negative and positive impact on the free-running intention. Studying the user behaviour would help to understand and design the persuasive methodologies.

User persuasive methods could be called design intent methods (Lockton et all 2010) which is the way of using the design or design element to alter usual negative user behaviour into a positive way to the building performance. For example, the installation of metering device showing the energy consumption has been used by the occupants would create user awareness. The competitive strategy of giving user access to the information of how well their spaces and buildings are performing in term of energy consumption compare to the others spaces or buildings would also help encourage the change of their behaviour.

Another useful strategies involving the persuasive method by show energy consumption meter in money currency which would remind how much they could save or over spent.

The last technique of controlling user behaviour is to reduce their adaptive opportunities.

The running schedule of systems or Automation system would help controlling the system in the way they were tended to be used.

0.50 0.00 JAN

FEB

MAR

APR MAY

JUN JULY AUG

SEP

OCT NOV

DEC

Fig. 8 The comparison of solar radiation on vertical surface between with and without shading device situation (South) S O L A R R A D I A T I O N O N V E RT I C A L S U R F A CE (A V E R A G E C U M D A I L Y) (K WH / M2) Without Shading Device East Glazing With Shading Device (2m. overhang or equivalent) East Glazing 2.50

2.00

1.50

1.00

0.50

0.00 JAN

FEB

MAR

APR MAY

JUN JULY AUG

SEP

OCT NOV

DEC

Fig. 9 The comparison of solar radiation on vertical surface between with and without shading device situation (East)

As previously stated, the shading device could be varies by design preferences. For example, external and internal blind could also be used as well as the mid-pane blind. Also the surface coated or tinted glazing also helps reducing solar gain at a certain level. However, to choose types of shading device, the factors of suitable properties, cost, and easiness of operating and maintenance.

4.2 PASSIVE COOLING : NATURAL VENTILATION The passive cooling strategies involve ventilation control. For the building to be free-running, the natural ventilation is one of the most important strategies as it is low in cost and could be effective way to reduce mechanical ventilation system and energy consumption. However, in busy road traffic city like Bangkok, air and noise pollutions are important factors of natural ventilation design. Consequently, the office low-rise office building in the high traffic zone should consider using the natural ventilation wisely.

4.1.2 Improve Building Envelope Performance Improving building envelope could be done in different way. Better thermal insulation would prevent the transferring heat between outside and inside. The improvement of windows design would balance between allow daylighting for internal space while still be able to control heat gain. Reducing air leakage also less fluctuated trends of another practical solution.

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(9.3 m2 per person = 279 m2). The space ceiling height is 3 m which means volume of space is 837 m3. The building infiltration was set at 1 ac/h (Jones 2008) with 1.80 W/m2K U-Value for triple glazing according to CIBSE concise handbook (Armstrong 2008).

Additionally, the disadvantage of natural ventilation is its unpredictable properties and the fact that sometimes it could create draught which would be disturbance in working environment.

5.1 Case 1 Using half typical summer ventilation rate for space cooling (Baker 2007) as base case, the analysis shows that the average outdoor temperatures (see Table 4) which can archive the comfort band (see Table1) are lower than monthly average outdoor temperatures (see Table1).

Table 4 Maximum Possible Outdoor Temperature to Archive Indoor Comfort Band (Case 1) Case 1 : 5.5 Ac/h Natural Ventilation Month Fig. 10 Natural Ventilation Strategies

Even in a tropical climate of Thailand, there might be periods that the outdoor temperature are adequately low to be useful in cooling the building; however, the unpredictable wind speed and direction might cause the system to be unreliable and the more flexible system for ventilation and cooling is highly required. The window design should be responsive to the flow of external wind. For example, the cross ventilation will create a cross flow of air within the space while high level vents would create an air flow using the difference of air temperature.

The study by Baker (2007) indicate the ventilation rate for space cooling for typical summer case at 2-12 ac/h. To archive the desired indoor condition and assure a natural ventilation performance, the control strategies such as wind speed & direction sensors as well as power actuators which would control the opening of the windows needed should be considered.

Night cooling is also considered useful in order to avoid full cooling load as the building thermal mass are cooled down by night air allow it to absorb more heat during daytime.

North West Glazing Glazing

South Glazing

East Average Glazing

JAN

28.2 °C

27.8 °C

27.1 °C

27.8 °C

27.7 °C

FEB

28.4 °C

27.7 °C

27.3 °C

27.7 °C

27.8 °C

MAR

28.8 °C

28.3 °C

28.3 °C

28.2 °C

28.4 °C

APR

29.1 °C

28.9 °C

29.1 °C

28.8 °C

29.0 °C

MAY

29.0 °C

28.9 °C

29.2 °C

28.9 °C

29.0 °C

JUN

28.7 °C

28.7 °C

29.0 °C

28.7 °C

28.8 °C

JUL

28.6 °C

28.5 °C

28.8 °C

28.6 °C

28.6 °C

AUG

28.5 °C

28.4 °C

28.6 °C

28.4 °C

28.5 °C

SEP

28.5 °C

28.2 °C

28.3 °C

28.2 °C

28.3 °C

OCT

28.6 °C

28.3 °C

28.0 °C

28.2 °C

28.3 °C

NOV

28.5 °C

28.1 °C

27.5 °C

28.1 °C

28.1 °C

DEC

28.2 °C

27.7 °C

27.0 °C

27.7 °C

27.7 °C

5.2 Case 2

5. STUDY MODEL ANALYSIS To determine period of free-running in Bangkok office space, the soft computations: Mean In door Temperature (Yannas 2015) were done on the study model in 3 different cases. The model analysis would give information regarding the maximum and minimum outdoor temperatures each cases can bare to gain mean indoor temperature with in the comfort band.

The study model is Bangkok typical office space in low-rise to high-rise building. The open plan office model contains moderate size office of 30 persons (see Fig.4). The space requirement per person according to Jones’s Metric Handbook (2008)

Fig. 11 Combined Cooling Strategies

Using base case and solar control strategies to reduce heat gain from solar radiation, the analysis shows that the average outdoor temperatures (see Table 5) which can archive the comfort band (see Table1) are still lower than the majority of monthly average outdoor temperatures. However, the average outdoor temperature of several winter months are within range.

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The case studies indicate that the free-running office building in Bangkok might be achievable at the high ventilation rate with help of solar control with 2m overhang shading devices or equivalent .

However, as stated earlier in (4.2), the ventilation rate would shift went the un predictable and uncontrollable wind speed and direction which mean that there is no guarantee of archiving 12 ac/h ventilation rate which lead to thermal comfort.

Table 5 Maximum Possible Outdoor Temperature to Archive Indoor Comfort Band (Case 2) Case 2 : 5.5 Ac/h Natural Ventilation & Shading Device Month North West South East Average Glazing Glazing Glazing Glazing JAN

28.3 °C

28.2 °C

28.1 °C

28.2 °C

28.2 °C

FEB

28.5 °C

28.3 °C

28.4 °C

28.3 °C

28.4 °C

MAR

28.9 °C

28.7 °C

28.9 °C

28.7 °C

28.8 °C

APR

29.4 °C

29.3 °C

29.4 °C

29.2 °C

29.3 °C

MAY

29.3 °C

29.3 °C

29.4 °C

29.3 °C

29.3 °C

JUN

29.1 °C

29.1 °C

29.2 °C

29.1 °C

29.1 °C

JUL

28.9 °C

28.9 °C

29.0 °C

28.9 °C

28.9 °C

AUG

28.8 °C

28.8 °C

28.8 °C

28.7 °C

28.8 °C

SEP

28.7 °C

28.6 °C

28.6 °C

28.6 °C

28.6 °C

OCT

28.7 °C

28.6 °C

28.6 °C

28.5 °C

28.6 °C

NOV

28.6 °C

28.4 °C

28.4 °C

28.4 °C

28.5 °C

DEC

28.2 °C

28.0 °C

28.0 °C

28.0 °C

28.1 °C

M A X I M U M P O S S I BL E O U T D O O R T E M P E R AT U RE T O A R C H I V E I N D O O R U P P E R C O M F OR T B A N D All Directions Glazing Average Case 1 All Directions Glazing Average Case 2 All Directions Glazing Average Case 3 31.0 °C 30.0 °C 29.0 °C 28.0 °C 27.0 °C

5.3 Case 3 Using maximum typical summer ventilation rate for space cooling (Baker 2007) and solar control strategies to reduce heat gain from solar radiation, the analysis shows that the average outdoor temperatures (see Table 6) which can archive the comfort band (see Table1) are still higher or within range of the monthly average outdoor temperatures which means that the space is averagely with in the comfort band if the calculated condition is achievable.

26.0 °C

Fig. 12 Maximum Possible Outdoor Temperature to Archive Upper Comfort Band M I N I M U M P O S S I B LE O U T D O O R T E M P E R AT U RE T O A R C H I V E I N D O O R L O W E R C O M F O RT B A N D All Directions Glazing Average Case 1

Table 6 Maximum Possible Outdoor Temperature to Archive Indoor Comfort Band (Case 2) Case 3 : 12 Ac/h Natural Ventilation & Shading Device Month North West South East Average Glazing Glazing Glazing Glazing JAN

29.5 °C

29.4 °C

29.4 °C

29.4 °C

29.4 °C

FEB

29.7 °C

29.6 °C

29.6 °C

29.6 °C

29.6 °C

MAR

30.1 °C

30.0 °C

30.0 °C

30.0 °C

30.0 °C

APR

30.6 °C

30.5 °C

30.6 °C

30.3 °C

30.5 °C

MAY

30.5 °C

30.5 °C

30.6 °C

30.5 °C

30.5 °C

JUN

30.3 °C

30.3 °C

30.4 °C

30.3 °C

30.3 °C

JUL

30.1 °C

30.1 °C

30.2 °C

30.1 °C

30.1 °C

AUG

29.9 °C

29.9 °C

30.0 °C

29.9 °C

29.9 °C

SEP

29.9 °C

29.8 °C

29.8 °C

29.8 °C

29.8 °C

OCT

29.9 °C

29.8 °C

29.8 °C

29.8 °C

29.8 °C

NOV

29.8 °C

29.7 °C

29.7 °C

29.7 °C

29.7 °C

DEC

29.4 °C

29.3 °C

29.3 °C

29.3 °C

29.3 °C

All Directions Glazing Average Case 2 All Directions Glazing Average Case 3 25.0 °C 24.0 °C 23.0 °C 22.0 °C 21.0 °C 20.0 °C

Fig. 13 Minimum Possible Outdoor Temperature to Archive Lower Comfort Band

The diagrams below (Fig. 14 - Fig. 25) show the more detail of daytime average outdoor temperature of each month in comparison with the model study outdoor temperature range of all cases.

This detailed study indicates that even though the daily average outdoor temperature are with in range but at typical office hours (9AM - 5PM) the building is actually used, the outdoor temperature would be with in range of possible indoor comfort band only in the morning period. The number of hours with in range varies from 1-4 hours.

5.4 Study Model Summary Fig 13 and Fig 14 shows comparison result between 3 cases. It could be seen clearly that the variation which impact the mean indoor temperature the most were the increasing of ventilation rate.

7/10

J ANUARY

AP RIL

To

Case 1 Max

Case 2 Max

Case 1 Min

Case 2 Min

Case 3 Min

Case 3 Max

Case 1 Max

Case 2 Max

Case 1 Min

Case 2 Min

Case 3 Min

Case 3 Max

Fig. 14 Monthly Analysis - January (Winter)

19:00

18:00

17:00

16:00

15:00

14:00

Case 1 Min

Case 2 Min

Case 3 Min

Case 3 Max

19:00

18:00

17:00

16:00

15:00

14:00

13:00

12:00

5:00

Fig. 15 Monthly Analysis - February (Summer)

11:00

36.0 °C 34.0 °C 32.0 °C 30.0 °C 28.0 °C 26.0 °C 24.0 °C 22.0 °C 20.0 °C

19:00

18:00

17:00

16:00

15:00

14:00

13:00

12:00

11:00

10:00

9:00

8:00

Case 2 Max

10:00

Case 3 Min

Case 1 Max

9:00

Case 2 Min

36.0 °C 34.0 °C 32.0 °C 30.0 °C 28.0 °C 26.0 °C 24.0 °C 22.0 °C 20.0 °C

To

8:00

Case 1 Min

Case 3 Max

7:00

Case 2 Max

6:00

Case 1 Max

7:00

13:00

MAY

To

6:00

12:00

Fig. 17 Monthly Analysis - April (Summer)

FE BRUARY

5:00

11:00

9:00

10:00

8:00

7:00

6:00

5:00

19:00

18:00

17:00

16:00

15:00

14:00

13:00

12:00

11:00

9:00

10:00

8:00

7:00

6:00

36.0 °C 34.0 °C 32.0 °C 30.0 °C 28.0 °C 26.0 °C 24.0 °C 22.0 °C 20.0 °C 5:00

36.0 °C 34.0 °C 32.0 °C 30.0 °C 28.0 °C 26.0 °C 24.0 °C 22.0 °C 20.0 °C

To

Fig. 18 Monthly Analysis - May (Summer)

MARCH

J UNE

To

Case 1 Max

Case 2 Max

Case 1 Min

Case 2 Min

Case 3 Min

Case 3 Max

36.0 °C 34.0 °C 32.0 °C 30.0 °C 28.0 °C 26.0 °C 24.0 °C 22.0 °C 20.0 °C

To

Case 1 Max

Case 2 Max

Case 1 Min

Case 2 Min

Case 3 Min

Case 3 Max

Fig. 16 Monthly Analysis - March (Summer)

Fig. 19 Monthly Analysis - June (Rainy)

8/10

19:00

18:00

17:00

16:00

15:00

14:00

13:00

12:00

11:00

10:00

9:00

8:00

7:00

6:00

5:00

19:00

18:00

17:00

16:00

15:00

14:00

13:00

12:00

11:00

10:00

9:00

8:00

7:00

6:00

5:00

36.0 °C 34.0 °C 32.0 °C 30.0 °C 28.0 °C 26.0 °C 24.0 °C 22.0 °C 20.0 °C

J ULY

OCTOBE R

To

Case 1 Max

Case 2 Max

Case 1 Min

Case 2 Min

Case 3 Min

Case 3 Max

Case 1 Max

Case 2 Max

Case 1 Min

Case 2 Min

Case 3 Min

Case 3 Max

Fig. 20 Monthly Analysis - July (Rainy)

19:00

18:00

17:00

16:00

15:00

14:00

13:00

Case 1 Min

Case 2 Min

Case 3 Min

Case 3 Max

18:00

19:00 19:00

17:00

18:00

16:00

15:00

14:00

13:00

12:00

5:00

Fig. 21 Monthly Analysis - August (Rainy)

11:00

36.0 °C 34.0 °C 32.0 °C 30.0 °C 28.0 °C 26.0 °C 24.0 °C 22.0 °C 20.0 °C

19:00

18:00

17:00

16:00

15:00

14:00

13:00

12:00

11:00

10:00

9:00

8:00

Case 2 Max

10:00

Case 3 Min

Case 1 Max

9:00

Case 2 Min

36.0 °C 34.0 °C 32.0 °C 30.0 °C 28.0 °C 26.0 °C 24.0 °C 22.0 °C 20.0 °C

To

8:00

Case 1 Min

Case 3 Max

7:00

Case 2 Max

6:00

Case 1 Max

7:00

12:00

N O V E MB ER

To

6:00

11:00

9:00

Fig. 23 Monthly Analysis - October (Rainy)

AUGUS T

5:00

10:00

8:00

7:00

6:00

5:00

19:00

18:00

17:00

16:00

15:00

14:00

13:00

12:00

11:00

9:00

10:00

8:00

7:00

6:00

36.0 °C 34.0 °C 32.0 °C 30.0 °C 28.0 °C 26.0 °C 24.0 °C 22.0 °C 20.0 °C

5:00

36.0 °C 34.0 °C 32.0 °C 30.0 °C 28.0 °C 26.0 °C 24.0 °C 22.0 °C 20.0 °C

To

Fig. 24 Monthly Analysis - November (Winter)

S E P T EMB ER

DE CE MBE R

To

Case 1 Max

Case 2 Max

Case 1 Min

Case 2 Min

Case 3 Min

Case 3 Max

36.0 °C 34.0 °C 32.0 °C 30.0 °C 28.0 °C 26.0 °C 24.0 °C 22.0 °C 20.0 °C

November To

November Case 1 Max

November Case 2 Max

November Case 3 Max

November Case 1 Min

November Case 2 Min

November Case 3 Min 35.0 °C 30.0 °C

Fig. 25 Monthly Analysis - December (Winter)

9/10

17:00

16:00

15:00

14:00

13:00

12:00

11:00

10:00

9:00

8:00

7:00

5:00

Fig. 22 Monthly Analysis - September (Winter)

6:00

20.0 °C

19:00

18:00

17:00

16:00

15:00

14:00

13:00

12:00

11:00

10:00

9:00

8:00

7:00

6:00

5:00

25.0 °C

6. CONCLUSION It could be concluded from the study that despite the fact the temperature in Winter and Rainy seasons of Bangkok is lower than summer, the existing office buildings which are not designed to be natural ventilated are hardly to be complete freerunning at anytime of the year.

The rise of temperature in the after noon which make the average high temperature to be within 30°C - 35°C range and the high internal gain cause the indoor temperature to rise above the upper comfort band. However, with the free-running strategies acquired from this research, it is possible to lower the cooling load and have several hours of free-running period with in every months. The free-running period could reach 3-4 hours in Winter and 2-3 hours in Rainy season and 1-2 hours in Summer which would reduce energy uses at a certain level.

Furthermore, with ventilation strategies and added solar control, the existing building might be able to reduce the cooling load of air-conditioning system.

However, the factors such as noise, pollution, and security should be seriously taken into account.

10/10

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Available at: http://tandfbis.s3.amazonaws.com/rt-media/pdf/9781844074860/monograph_3.pdf (Downloaded: 20 November 2015).

Boonyou, S. and Jitkhajornwanich, K. (2000) 'Enhancement of Natural Ventilation in Office Building in Bangkok', in Steemers, K. and Yannas, S. (ed.) Architecture City Environment: Proceeding of PLEA 2000.

London: James & James (Science Publisher), pp. 259-261.

Brager, G.S. and de Dear, R. (2001) Climate, Comfort & Natural Ventilation: A new adaptive comfort standard for ASHRAE Standard 55. Available at: http://repositories.cdlib.org/cedr/cbe/ieq/Brager2001 Windsor AdaptiveComfort (Downloaded: 20 October 2015).

Brunelli, G. (2015) 'ClimProcess_SED_v2' [Worksheets]. Term1 Lecture Series & Software Workshops: Environmental Simulation & Performance Assessment Tools.

Busch, J.F. (1995) 'Thermal Response to the Thai Office Environment', in Humphreys, M., Nicol, F., Sykes, O. and Roaf, S. (ed.) Standard for Thermal Comfort: Indoor Air Temperature Standard for the 21st Century.

Cornwall: T.J. Press (Padstow), pp. 114-134.

Davidson, S. (2015) Grasshopper (For Rhino 5.0) [Computer program]. Available at: http:// www.grasshopper3d.com/page/download-1 (Downloaded: 27 October 2015).

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Irving, S., Ford, B. and Etheridge, D. (2005) Natural ventilation in non-domestic buildings CIBSE Applications Manual AM10. Edited by Butcher, K. London : CIBSE Jitkhajornwanich, K. (2006) 'Shifting Comfort Zone for Hot-Humid Environments', PLEA2006: The 23rd Conference on Passive and Low Energy Architecture. Geneva, 6-8 September. Publisher. Available at: http:// plea-arch.org/ARCHIVE/2006/ (Accessed: 20 November 2015).

Jitkhajornwanich, K., Pitt, A.C., Malama, A. and Sharples, S. (1998) 'Thermal comfort in transitional spaces in the cool season of Bangkok', in Maldonado, E. and Yannas, S. (ed.) Environmentally Friendly Cities: Proceeding of PLEA 1998 Passive and Low Energy Architecture, 1998, Lisbon, Portugal, June 1998. Reprint, New York Routledge, 2014, pp. 357-360.

Jones, P. (2008) Metric Handbook: Planning and Design Data. 3rd Edition. Edited by Littlefield, D. Oxforc: Architecture Press (Elsevier).

Koch-Nielsen, H. (2002) Stay Cool: A Design Guide for The Built Environment in Hot Climate. Reprint, New York: Earthscan, 2007.

Littlefair, P. (2006) Design for improved solar shading control CIBSE TM37. Edited by Butcher, K. London : CIBSE Lockton, D., Harrison, D., and Stanton, N. (2008). ‘Making the user more efficient: Design for sustainable behaviour’, International journal of sustainable engineering, issue 1, pp.3-8.

Lockton, D., Harrison, D., and Stanton, N. (2010). ‘The Design with Intent Method: A design tool for influencing user behaviour’, Applied ergonomics, Issue 41(3), pp. 382-392.

Mahdavi, A. and C. Proglhof (2008). Observation-based models of user control actions in buildings. Proc.

PLEA 2008, Dublin.

Parsloe, C. (2005) Sustainable low energy cooling: an overview CIBSE Knowledge Series KS3. Edited by Race, G.L. and Butcher, K. London : CIBSE Pelsmakers, S. (2012) The Environmental Design Pocket Book. London: RIBA Publishing.

Robert McNeel & Associates (2015) Rhinoceros (5.0) [Computer program]. Available at: https:// www.rhino3d.com/download (Downloaded: 27 October 2015).

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Taweekun, J. and Tantiwichien, A. (2013) ‘Thermal Comfort Zone for Thai People’, Engineering, Issue 5, pp.

525-529. doi: 10.4236/eng.2013.55062 Yannas, S. (2008) ‘Challenging the Supremacy of Airconditioning’, 2A Architecture & Art, Issue 7, pp. 20-43, Dubai.

Yannas, S. (2015) ‘Soft Computation : Mean Indoor Temperature' [Excel Worksheets]. Term1 Lecture Series & Software Workshops: Environmental Simulation & Performance Assessment Tools.

THESIS Amenábar, T.S. (2013) Rethinking Office Building Typology in Continental Mediterranean Climate: A Critical Review of Current Layout, Building Form and Design Parameters. MArch Dissertation. Architectural Association School of Architecture.

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