Optimum overhang geometry for high rise office building energy saving in tropical climates

vii

TABLE OF CONTENTS CHAPTER TITLE PAGE

THESIS TITLE i

DECLARATION ii

DEDICATION iii

ACKNOWLEDGEMENT iv

ABSTRACT (ENGLISH) v

ABSTRAK (BAHASA MELAYU) vi

TABLE OF CONTENTS vii

LIST OF TABLES xvi

LIST OF FIGURES xxi

LIST OF ABBREVIATIONS xxx

LIST OF SYMBOLS xxxiii

LIST OF APPENDIXES xxxix

1 GENERAL INTRODUCTION

1.1 Introduction 1

1.2 The Problem Statement

4

1.3 Research Hypothesis

5

1.4 Research Questions

6

1.5 Research Gap

6

1.6 Research Objective

9

1.7 Scope and Limitations

10

1.8 Importance of the Research

12

viii

1.9 Thesis Organization 13

2 SOLAR RADIATION AND ANALYSIS OF MALAYSIAN SKY CONDITIONS

2.1 Solar Radiation: Source of Heat and Light 17

2.2 Solar Geometry

18

2.3 Solar Distribution

19

2.3.1 Solar Intensity

20

2.3.2 Components of Solar Radiation: Direct,

Diffuse and Reflected Radiation

20

2.4 Solar Radiation Calculation

22

2.4.1 Calculation of Clear Sky Solar Radiation

23

2.4.2 Solar Radiation Calculations on Horizontal Surfaces

24

2.4.3 Solar Radiation Calculations on Vertical Surfaces

25

2.5 Analysis of Kuala Lumpur Sky Conditions

26

2.5.1 Sky Condition

27

2.5.2 Solar Radiation Analysis

30

2.5.3 Outdoor Design Temperature Analysis

37

2.5.4 Exterior Illuminance Analysis

40

2.6 Summary

47

3 ENERGY USE IN HIGH-RISE BUILDING, HEAT GAIN AND SOLAR SHADING

3.1 Energy Consumption Pattern in Malaysia 50

3.1.1 Energy Consumption in Buildings

51

3.1.1.1 Energy Efficient Building Codes and

Standards

52

ix

3.1.2 Basic Principles of Energy Efficiency in High-rise Buildings

54

3.1.2.1 Climate Rejecting Building

55

3.1.2.2 Climate Adapted Building

56

3.1.2.3 Combination of Climate Adapted and

Climate Rejected Building

57

3.1.3 Review Related Research on High-Rise

Office Building

59

3.1.3.1 High-rise Building Form and

Orientation

60

3.1.3.2 High-Rise Building Core

62

3.1.3.3 The Floor Plan

64

3.1.3.4 Building Envelope

66

3.1.3.5 Court Yards, Atria, Wind Scoops and

Open Corridors

68

3.2 Heat Gains

69

3.2.1 Modes of Heat Transfer in Buildings

69

3.2.1.1 Conduction

69

3.2.1.2 Convection

70

3.2.1.3 Radiation

70

3.2.2 Types of Heat Transfer in Buildings

71

3.2.2.1 Heat Transfer through Building Fabric

71

3.2.2.2 Heat Gain through Window

72

3.2.2.3 Infiltration

78

3.2.2.4 Impact of Electric Lighting

79

3.2.2.5 Occupants Heat Gains

81

3.2.2.6 Equipment Heat Gains

81

3.3 Solar Shading

82

x

3.3.1 Analysis of Types of Shading Devices 84

3.3.1.1 Orientation

84

3.3.1.2 Vegetation

85

3.3.1.3 Internal Devices

86

3.3.1.4 External Devices

88

3.3.2 Method of Designing a Shading Device

90

3.3.2.1 Shadow Angles

90

3.3.2.2 Shading Mask and Sun-Path Diagram

91

3.3.2.3 Awning Geometry

94

3.3.3 Heat Gain through Externally Shaded Window

96

3.3.4 Effectiveness of External Shading Device

98

3.3.5 Factors Affecting the Effectiveness of Shading

Device

99

3.3.5.1 Geometry of External Shading Device

99

3.3.5.2 Surface Properties and Color

103

3.3.5.3 Location of Shading Device

104

3.3.5.4 Effectiveness of Different External

Horizontal Shading Methods

105

3.3.5.5 Shading Device Optical Properties

105

3.3.6 External Shading Device and Side-lit Daylight

Concept

109

3.3.6.1 Adequate Illuminance on the Work

Surface

111

3.3.6.2 Daylight Factor and Sun Illuminance

Ratio

112

3.3.6.3 Daylight –Electric Light Integration

116

3.3.7 Research on Solar Shading

119

xi

3.3.7.1 Shading Strategies and Solar Radiation 119

3.3.7.2 Shading Strategies and Daylight

121

3.3.7.3 Solar Shading and Energy Related

Experiments

124

3.3.7.4 Solar Shading Design Methods

127

3.3.7.5 Solar Shading and Human Perception

128

3.4 Summary

129

4 METHODOLOGY

4.1 The Need for the Experiment 132

4.2 Development of Simplified Office Room

Configuration

133

4.2.1 Office Room Geometry

134

4.2.2 Window Size and Work Plane Height

134

4.2.3 External Overhang

135

4.2.4 Office Room Characteristics

137

4.3 Methods of Energy Evaluation

137

4.3.1 Simplified Energy Calculation Methods

138

4.3.2 Detailed Energy Calculation Methods

139

4.4 Methods of Studying Energy in Buildings

141

4.4.1 Manual Calculation Methods

142

4.4.2 Field Experiment or Full Scale Method

142

4.4.3 Computer Simulation

143

4.5 Selection of Computer Program

144

4.5.1 Experimental Requirement

145

4.5.2 Review of Energy Simulation Programs

146

xii

4.6 The eQUEST-3 Computer Simulation Program

147

4.6.1 Simulation Procedure

148

4.6.1.1 Step I: Data Requirement

149

4.6.1.2 Step II: Preparation of the Models

149

4.6.1.3 Step III: Detailed Interface-Selecting

Simulation Parameters and Perform Simulation

155

4.6.1.4 Step IV: Review Simulation Results

157

4.6.2 Simulation Limitations

158

4.6.3 Simulation Design Conditions

160

4.6.3.1 Office Room Characteristics

160

4.6.3.2 Indoor Design Conditions

160

4.6.3.3 Internal Load

162

4.6.3.4 Operating Schedules

163

4.6.3.5 Outdoor Design Conditions

163

4.7 Simulation Analysis Criteria

165

4.8 Summary

169

5 RESULTS, ANALYSIS AND FINDINGS: SOLAR RADIATION AND WORK PLANE ILLUMINANCE

5.1 Incident and Transmitted Solar Radiation 171

5.1.1 East Orientation

172

5.1.2 West orientation

175

5.1.3 North Orientation

179

5.1.4 South Orientation

182

5.1.5 Influence of Solar Radiation Components on

Base Case Model

184

xiii

5.1.6 Impact of Overhang on Direct Solar Radiation Incident on Window

188

5.1.7 Impact of Overhang on Diffuse Solar

Radiation Incident on Window

190

5.1.8 Impact of Overhang on Transmitted and Re-

Transmitted Solar Heat Gain through Window System

191

5.1.8.1 Hourly Variation of Transmitted and

Re-Transmitted Solar Heat Gain through Window System

193

5.2 Absolute Work Plane Illuminance

197

5.2.1 East Orientation

198

5.2.1.1 Window Height to Room Depth Ratio-

East Orientation

203

5.2.2 West Orientation

206


West Orientation

211

5.2.3 North Orientation

213


North Orientation

218

5.2.4 South Orientation

219


South Orientation

224

5.2.5 Hourly Variation of Work Plane Illuminance

226

5.2.6 External Horizontal Overhang and Work Plane

Illuminance

229

5.2.6.1 Impact of Overhang on Target

Illuminance Level (500lux)

229

5.2.6.2 Window Height to Room Depth Ratio

231

5.3 Summary

232

xiv

6 RESULTS, ANALYSIS AND FINDINGS: ENERGY PERFORMANCE

6.1 Energy Evaluation 234

6.2. Building Component Cooling Loads

235

6.2.1 Base Case Generic Office Room and Building

Component Cooling Loads

235

6.2.2 Influence of External Horizontal Overhang on

Building Component Cooling Loads

237

6.3 Electricity Consumption

245

6.3.1 Annual Electricity Consumption- Base Case

245

6.3.1.1 Influence of Orientation on Annual

Electricity Consumption- Base Case

248

6.3.2 External Horizontal Overhang and Annual

Electricity Consumption

250

6.3.2.1 Incremental Electricity Use

254

6.3.2.2 Influence of External Horizontal

Overhang on Annual Electricity Consumption

266

6.4 Summary

269

7 CONCLUSION

7.1 Review of Thesis Objectives and Research Questions 271

7.2 Thesis Conclusion

272

7.2.1 External Horizontal Overhang and Solar Radiation

273

7.2.2 External Horizontal Overhang and Work Plane

Illuminance

275

7.2.3 Base-case Generic Office Room: Building


277

7.2.4 External Horizontal Overhang and Building


278

xv

7.2.5 Base-case Generic Office Room and Energy Consumption

280

7.2.6 External Horizontal Overhang and Building

Energy Consumption

281

7.2.7 Optimum Overhang Ratios for Hot Humid

Tropical Climate

283

7.3 Application of the eQUEST-3 (DOE 2.2) Energy

Simulation in Malaysian Conditions

285

7.4 Suggestions for Further Research

286

BIBLIOGRAPHY 289 APPENDICES 305

A

Summary of Energy Related Research

306

C

Summary of High-rise Office Building and Energy Use

Review

C1

Office Buildings Energy Database, Kuala Lumpur Malaysia

309

C2

South East Asian Office Buildings Information

312

C3

Design of Shading Device Considering the Windows Solar Angle Dependent Properties: With Special Reference to Kuala Lumpur Hot Humid Tropical Climate

315

D

Review of Computer Simulation Programs

329

E

Simulation Data and Results

E1

Sample of Input Data

333

E2

Summary: Direct and Diffused Incident Solar Radiation and Transmitted Heat Gains

338

E3

Summary: Work Plane Illuminance at Ref.Pt:01 and Ref.Pt:02

344

F

F1

Summary: Building Cooling Load Data

347

F2

Summary: End Use Energy Consumption Data with

Natural-light utilization

350

xvi

LIST OF TABLES TABLE NO.

TITLE PAGE

1.1 Summary of previous research related to solar shading, daylight and energy use

8

2.1

ASHRAE (1999) clear sky model data for 21 day of each month

24

2.2

Different Sky types according to Nebulosity Index, Subang Jaya Malaysia

29

2.3

Comparison of measured SMS and DOE-weather file data for hourly horizontal solar radiation for Kuala Lumpur (2001) (Latitude: 3.120 , Longitude: +101.60,Time zone: +7)

31

2.4

Monthly mean global horizontal solar radiations (W/m2) and MBE & RMSE values for SMS and DOE.wf (Kuala Lumpur)

32

2.5

Hourly direct normal solar radiations (x cloud cover) and diffuse horizontal solar radiation (x cloud cover) - DOE. wf. (Kuala Lumpur); (W/m2)

34

2.6

Percentage of direct normal solar radiation and diffused horizontal solar radiation, DOE.wf for Kuala Lumpur (2001)

34

2.7

Monthly mean values of DBT, WBT and DewPT and correspondence Mean Bias Error (MBE) values

40

2.8

Horizontal exterior diffuse illuminance values (clear sky & overcast sky) on 21 March, 22 June, 24 September and 21 December, DOE.wf (Kuala Lumpur)

45

2.9

Hourly maximum global exterior illuminance for 21 March, 22 June, 24 September and 21 December, DOE.wf. (Kuala Lumpur)

45

xvii

2.10 Monthly maximum exterior illuminance values from clear sky, overcast sky and direct sun, DOE.wf, (Kuala Lumpur)

46

3.1

Electricity intensity averages for ASEAN countries

52

3.2

Electricity consumption percentages by building components for ASEAN countries

52

3.3

Optimum overhang ratio to intercept maximum direct incident solar radiation; Latitude: 3.120, Longitude: + 101.60- East, West, North and South

101

3.4

Recommended average illuminance levels for office buildings

112

3.5

Standard lowest exterior diffuse illuminance (lux) from Sky for different climatic regions

114

4.1

Description of tested overhang depths of the experiment

136

4.2

Summary of shading strategy with design variables and performance variables

151

4.3

Variables and constants of the study

165

4.4

Data analysis indicators and their interpretation

166

5.1

Summary of cumulative direct and diffuse solar radiation incident and total transmitted heat gain for base case model with percentage values compared to total incident solar radiation on bare window

185

5.2

Summary of maximum intensity of direct and diffuse solar radiation incident and total transmitted heat gain through bare window on east, west, north and south orientations

187

5.3a

Maximum, minimum and mean work plane illuminance values at ref. pt: 01, ref. pt: 02, and total solar heat gain- 21 March and 22 June, East orientation

202

5.3b

Maximum, minimum and mean work plane illuminance values at ref. pt: 01, ref. pt: 02, and total solar heat gain- 24 September and 21 December, East orientation

203

5.4a

Maximum, minimum and mean work plane illuminance values at ref. pt: 01, ref. pt: 02, and total solar heat gain- 21 March and 22 June, West orientation

209

xviii

5.4b Maximum, minimum and mean work plane illuminance values at ref. pt: 01, ref. pt: 02, and total solar heat gain- 24 September and 21 December, West orientation

210

5.5a

Maximum, minimum and mean work plane illuminance values at ref. pt: 01, ref. pt: 02, and total solar heat gain- 21 March and 22 June, North orientation

216

5.5b

Maximum, minimum and mean work plane illuminance values at ref. pt: 01, ref. pt: 02, and total solar heat gain- 24 September and 21 December, North orientation

217

5.6a

Maximum, minimum and mean work plane illuminance values at ref. pt: 01, ref. pt: 02, and total solar heat gain- 21 March and 22 June, South orientation

223

5.6b

Maximum, minimum and mean work plane illuminance values at ref. pt: 01, ref. pt: 02, and total solar heat gain- 24 September and 21 December, South orientation

224

5.7

Reduction percentages of cumulative direct, diffuse and transmitted solar radiation for optimum overhang ratio for target work plane illuminance level

231

5.8

Summary of optimum overhang ratio for incident solar radiations, transmitted heat gains and work plane illuminance

232

6.1

Annual cooling load (MWh) with natural-light utilization and reduction percentage values as compared to base-case model, for tested OHR-East orientation

238

6.2

Annual cooling load (MWh) with natural-light utilization and reduction percentage values as compared to base-case model, for tested OHR-West orientation

239

6.3

Annual cooling load (MWh) with natural-light utilization and reduction percentage values as compared to base-case model, for tested OHR-North orientation

240

6.4

Annual cooling load (MWh) with natural-light utilization and reduction percentage values as compared to base-case model, for tested OHR-South orientation

240

6.5

Summary of building cooling loads and reduction percentages for optimum overhang ratio compared to base-case model, East, West, North and South orientations

242

xix

6.6 The annual total cooling load (MWh) with and without natural-light utilization for base-case model and maximum overhang option, East, West, North and South orientations

245

6.7

The annual electricity consumption for base case (w/o shading devices) model, with and without natural-light utilization, East, West, North and South orientations

247

6.8

Summary of impact of artificial lighting on space cooling energy consumption for base-case generic office room, East, West, North and South orientations

250

6.9

Regression coefficients as a function of overhang ratio for incremental electricity use for area lighting (IEULt) - East, West, North and South orientations

259

6.10

Regression coefficients as a function of overhang ratio for incremental electricity use for space cooling (IEUCL) - East, West, North and South orientations

260

6.11

Regression coefficients as a function of overhang ratio for total incremental electricity use (IEUTOT) - East, West, North and South orientations

261

6.12

Comparison of simulated (e-QUEST-3) to interpolated (regression equation) IEUCL (kWh/m2, yr) for tested overhang ratio

262

6.13

Comparison of simulated (e-QUEST-3) to interpolated (regression equation) IEULt (kWh/m2, yr) for tested overhang ratio

262

6.14

Comparison of simulated (e-QUEST-3) to interpolated (regression equation) IEUTOT (kWh/m2, yr) for tested overhang ratio

263

6.15

Summary of total energy saving and respective work plane illuminance for optimum overhang ratio, East, West, North and South orientations

267

6.16

Summary of energy saving for space cooling and respective work plane illuminance for optimum overhang ratio, East, West, North and South orientations

268

6.17

Summary of lighting energy consumption for optimum overhang ratio for space cooling, East, West, North and South orientations

269

xx

6.18 Summary of lighting energy consumption for optimum overhang ratio for total energy consumption, East, West, North and South orientations

269

7.1

Influence of maximum overhang ratio on direct, diffused solar radiation and total transmitted heat gain, East, West, North and South orientations

274

7.2

Trade-Off between optimum overhang ratios and performance variables for direct incident solar radiation, transmittance heat gain and mean work plane illuminance, East, West, North and South orientations

277

7.3

Trade-Off between optimum overhang ratio and building cooling load components, East, West, North and South orientations

279

7.4

Summary of optimum overhang ratio for total energy consumption and space cooling energy consumption

282

7.5

Summary of optimum overhang ratio for various performance variables on east, west, north and south orientations for tropical climate

283

xxi

LIST OF FIGURES FIGURE

NO TITLE PAGE

1.1 The Problem: A typical fully glazed office space section 5

1.2 The Proposition: Optimum shading during over heated period to reduce total heat gain and obtain target illuminance

5

1.3

User requirements for solar shading systems

13

1.4

The flow of research process and thesis structure

16

2.1

Comparison of global horizontal solar radiation between SMS (measured) and DOE-wf (simulated) for Kuala Lumpur- 21 March, 22 June, 24 September and 21 December

33

2.2

Hourly total solar radiations (direct & diffuse) on vertical surface on 21 March

35

2.3

Hourly total solar radiations (direct & diffuse) on vertical surface on 22 June

35

2.4

Hourly total solar radiations (direct & diffuse) on vertical surface on 24 September

36

2.5

Hourly total solar radiations (direct & diffuse) on vertical surface on 21 December

36

2.6

Hourly variations of dry bulb temperature (DBT) for 21 March, 22 June, 24 September and 21 December, DOE. wf. for Kuala Lumpur

37

2.7

Hourly variations of wet bulb temperature (WBT) for 21 March, 22 June, 24 September and 21 December, DOE. wf. for Kuala Lumpur

38

2.8

Comparison of monthly mean DBT (0C) data from SMS and DOE.wf

38

xxii

2.9 Comparison of monthly mean WBT (0C) data from SMS and DOE.wf

39

2.10

Monthly variation of Dew Point Temperatures (0C) data from SMS and DOE.wf

39

2.11

Exterior horizontal illuminance for 21 March, DOE.wf data for Kuala Lumpur

41

2.12

Exterior horizontal illuminance for 22 June, DOE.wf data for Kuala Lumpur

42

2.13

Exterior horizontal illuminance for 24 September, DOE.wf data for Kuala Lumpur

42

2.14

Exterior horizontal illuminance for 21 December, DOE.wf data for Kuala Lumpur

43

2.15

Total exterior horizontal illuminance, DOE.wf data for Kuala Lumpur

44

2.16

Calculated global luminous efficacies (lm/W), DOE.wf data for Kuala Lumpur

44

2.17

Monthly maximum exterior illuminance values from clear sky, overcast sky and direct sun, DOE.wf (Kuala Lumpur)

46

3.1

Examples of climate rejecting high-rise buildings in Malaysia

56

3.2

Example of climate adapted building: Public Works Department (PWD or JKR) building, Kuala Lumpur

57

3.3

Combination of climate adapted and rejected buildings in Malaysia

58

3.4

Optimum high-rise building form according to climatic zones

61

3.5

Arrangement of vertical core according to climatic zones

63

3.6

Core plan and annual cooling loads

63

3.7

Instantaneous heat balances through sunlit glazing material

73

3.8

External solar shading devices horizontal overhang, vertical shading devices and egg-crate devices

89

3.9

Horizontal shadow angle (HSA)

90

xxiii

3.10 Vertical shadow angle (VSA) 91

3.11 The shadow angle protractor

92

3.12

Stereographic projections for Kuala Lumpur (Latitude 3.120, Longitude +101.60, and Time zone 7)

92

3.13

Relationship between horizontal shading depth, window height and vertical shadow angle (VSA)

93

3.14

Sideway extension of external horizontal shading device

94

3.15

Relationship between vertical fin’s depth, window width and horizontal shadow angle (HSA)

94

3.16

Awning geometry

95

3.17

Relationship between external overhang depth, window height and overhang ratio

100

3.18

Overhang ratio for side extension of horizontal shading device

102

3.19

Effect of overhang on daylight distribution in a room

110

4.1

Base case office room configuration

135

4.2

Office room with overhang design

136

4.3

Sequential simulation approach

140

4.4

Simultaneous simulation approach

141

4.5

DOE 2.2 Simulation engine structure

148

4.6

Calculation procedure of loads from heat gains

149

4.7

Typical eQUEST-3 building wizard screen

150

4.8

The eQUEST-3 exterior window shades and blinds wizard screen

152

4.9

The eQUEST-3 daylight zoning wizard screen

153

4.10

The eQUEST-3 HVAC system wizard screen

154

4.11

The eQUEST-3 detail interface screen

156

4.12

The eQUEST-3 hourly results selection screen

156

xxiv

4.13 The eQUEST-3 results screen of annual end use energy consumption

157

4.14

The eQUEST-3 simulation procedures

157

4.15

Daylight photo sensor positions in office room model

161

4.16

Overall simulation procedures with design variables and performance variables

168

5.1

Direct, diffuse solar radiation incident on window, and transmitted and re-conducted solar heat gain (W/m2), as a function of overhang ratio- 21 March, East orientation

173

5.2

Direct, diffuse solar radiation incident on window, and transmitted and re-conducted solar heat gain (W/m2), as a function of overhang ratio- 22 June, East orientation

173

5.3

Direct, diffuse solar radiation incident on window, and transmitted and re-conducted solar heat gain (W/m2), as a function of overhang ratio- 24 September, East Orientation

174

5.4

Direct, diffuse solar radiation incident on window, and transmitted and re-conducted solar heat gain (W/m2), as a function of overhang ratio- 21 December, East Orientation

174

5.5

Direct, diffuse solar radiation incident on window, and transmitted and re-conducted solar heat gain (W/m2), as a function of overhang ratio- 21 March, West orientation

176

5.6

Direct, diffuse solar radiation incident on window, and transmitted and re-conducted solar heat gain (W/m2), as a function of overhang ratio- 22 June, West orientation

177

5.7

Direct, diffuse solar radiation incident on window, and transmitted and re-conducted solar heat gain (W/m2), as a function of overhang ratio- 24 September, West orientation

177

5.8

Direct, diffuse solar radiation incident on window, and transmitted and re-conducted solar heat gain (W/m2), as a function of overhang ratio- 21 December, West orientation

178

5.9

Direct, diffuse solar radiation incident on window, and transmitted and re-conducted solar heat gain (W/m2), as a function of overhang ratio- 21 March, North orientation

179

5.10

Direct, diffuse solar radiation incident on window, and transmitted and re-conducted solar heat gain (W/m2), as a function of overhang ratio- 22 June, North orientation

180

xxv

5.11 Direct, diffuse solar radiation incident on window, and transmitted and re-conducted solar heat gain (W/m2), as a function of overhang ratio- 24 September, North orientation

180

5.12

Direct, diffuse solar radiation incident on window, and transmitted and re-conducted solar heat gain (W/m2), as a function of overhang ratio- 21 December, North orientation

181

5.13

Direct, diffuse solar radiation incident on window, and transmitted and re-conducted solar heat gain (W/m2), as a function of overhang ratio- 21 March, South orientation

182

5.14

Direct, diffuse solar radiation incident on window, and transmitted and re-conducted solar heat gain (W/m2), as a function of overhang ratio- 22 June, South orientation

183

5.15

Direct, diffuse solar radiation incident on window, and transmitted and re-conducted solar heat gain (W/m2), as a function of overhang ratio- 24 September, South orientation

183

5.16

Direct, diffuse solar radiation incident on window, and transmitted and re-conducted solar heat gain (W/m2), as a function of overhang ratio- 21 December, South orientation

184

5.17

Cumulative direct, diffuse and total incident solar radiation and total transmitted heat gains for base-case model with bare window on east, west, north and south orientations

186

5.18

Maximum intensity of direct and diffuse incident solar radiation and total transmitted heat gain for base-case model- East, West, North and South orientations

188

5.19

Reduction percentage (%) of cumulative amount of direct solar radiation incident on window surface as function of horizontal overhang ratio- East, West, North and South

189

5.20

Reduction percentage (%) of cumulative amount of diffuse solar radiation incident on window surface as function of horizontal overhang ratio- East, West, North and South

191

5.21

Reduction percentage (%) of cumulative transmitted and re-conducted solar heat gain in an office room space as function of horizontal overhang ratio- East, West, North and South

192

5.22

Maximum hourly total solar heat gains for tested overhang ratios- East orientation

193

5.23

Maximum hourly total solar heat gains for tested overhang ratios- West orientation

194

xxvi

5.24 Maximum hourly total solar heat gains for tested overhang ratios- North orientation

194

5.25

Maximum hourly total solar heat gains for tested overhang ratios- South orientation

195

5.26

Absolute work plane illuminance (lux) at ref.pt:01, ref.pt:02, and solar heat gain (W/m2), as a function of overhang ratio- 21 March, East orientation

198

5.27

Absolute work plane illuminance (lux) at ref.pt:01, ref.pt:02, and solar heat gain (W/m2), as a function of overhang ratio- 22 June, East orientation.

198

5.28

Absolute work plane illuminance (lux) at ref.pt:01, ref.pt:02, and solar heat gain (W/m2), as a function of overhang ratio- 24 September, East orientation

199

5.29

Absolute work plane illuminance (lux) at ref.pt:01, ref.pt:02, and solar heat gain (W/m2), as a function of overhang ratio- 21 December, East orientation

199

5.30

Mean work plane illuminance (lux) at reference point 01 for tested overhang ratio- 21 March, 22 June, 24 September, and 21 December- East orientation.

204

5.31

Mean work plane illuminance (lux) at reference point 02 for tested overhang ratio- 21 March, 22 June, 24 September, and 21 December- East orientation

204

5.32

Effect of overhang on natural light distribution in perimeter office room- East orientation

205

5.33

Absolute work plane illuminance (lux) at ref.pt:01, ref.pt:02, and solar heat gain (W/m2), as a function of overhang ratio- 21 March, West orientation

206

5.34

Absolute work plane illuminance (lux) at ref.pt:01, ref.pt:02, and solar heat gain (W/m2), as a function of overhang ratio- 22 June, West orientation

206

5.35

Absolute work plane illuminance (lux) at ref.pt:01, ref.pt:02, and solar heat gain (W/m2), as a function of overhang ratio- 24 September, West orientation

207

5.36

Absolute work plane illuminance (lux) at ref.pt:01, ref.pt:02, and solar heat gain (W/m2), as a function of overhang ratio- 21 December, West orientation

207

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5.37 Mean work plane illuminance (lux) at reference point 01 for tested overhang ratio- 21 March, 22 June, 24 September and 21 December for West orientation.

211

5.38

Mean work plane illuminance (lux) at reference point 02 for tested overhang ratio- 21 March, 22 June, 24 September and 21 December for West orientation

212

5.39

Effect of overhangs on natural light distribution in perimeter office room- West orientation

212

5.40

Absolute work plane illuminance (lux) at ref.pt:01, ref.pt:02, and solar heat gain (W/m2), as a function of overhang ratio- 21 March, North orientation

213

5.41

Absolute work plane illuminance (lux) at ref.pt:01, ref.pt:02, and solar heat gain (W/m2), as a function of overhang ratio- 22 June, North orientation

213

5.42

Absolute work plane illuminance (lux) at ref.pt:01, ref.pt:02, and solar heat gain (W/m2), as a function of overhang ratio- 24 September, North orientation

214

5.43

Absolute work plane illuminance (lux) at ref.pt:01, ref.pt:02, and solar heat gain (W/m2), as a function of overhang ratio- 21 December, North orientation

214

5.44

Mean work plane illuminance (lux) at reference point 01 for tested overhang ratio- 21 March, 22 June, 24 September, and 21 December for North orientation

218

5.45

Mean work plane illuminance (lux) at reference point 02 for tested overhang ratio- 21 March, 22 June, 24 September and 21 December for North orientation.

218

5.46

Effect of overhangs on natural-light distribution in perimeter office room- North orientation

219

5.47

Absolute work plane illuminance (lux) at ref.pt:01, ref.pt:02, and solar heat gain (W/m2), as a function of overhang ratio- 21 March, South orientation

221

5.48

Absolute work plane illuminance (lux) at ref.pt:01, ref.pt:02, and solar heat gain (W/m2), as a function of overhang ratio- 22 June, South orientation.

221

5.49

Absolute work plane illuminance (lux) at ref.pt:01, ref.pt:02, and solar heat gain (W/m2), as a function of overhang ratio- 24 September, South orientation

222

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5.50 Absolute work plane illuminance (lux) at ref.pt:01, ref.pt:02, and solar heat gain (W/m2), as a function of overhang ratio- 21 December, South orientation.

222

5.51

Mean work plane illuminance (lux) at reference point 01 for tested overhang ratio- 21 March, 22 June, 24 September and 21 December for South orientation.

225

5.52

Mean work plane illuminance (lux) at reference point 02 for tested overhang ratio- 21 March, 22 June, 24 September and 21 December for South orientation.

225

5.53

Effect of overhangs on natural-light distribution in perimeter office room- South orientation

226

5.54

Minimum hourly work plane illuminance at reference point 02, East orientation

227

5.55

Minimum hourly work plane illuminance at reference point 02, West orientation

227

5.56

Minimum hourly work plane illuminance at reference point 02, North orientation

228

5.57

Minimum hourly work plane illuminance at reference point 02, South orientation

228

6.1

Breakdown of annual cooling load (MWh) with natural-light utilization and without natural-light for a base-case generic office room- East, West, North and South orientations

236

6.2

Total envelop and internal component cooling loads (MWh) for tested external horizontal overhang ratio, East, West, North and South orientations

241

6.3

Total building space cooling load (MWh) for tested external horizontal overhang ratio, East, West, North and South orientations

242

6.4

Breakdown of annual cooling load (MWh) without natural-light utilization; for base-case model and maximum overhang option, East, West, North and South orientations

243

6.5

The annual total cooling load (MWh) with and without natural-light utilization for base-case model and maximum overhang option, East, West, North and South orientations

244

6.6

Breakdown of annual electricity consumption for base case model, with and without natural-light utilization- East, West, North and South orientations

246

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6.7 Total energy consumption with and without natural-light scheme for base case model, East, West, North and South orientations

247

6.8

(a & b)

Electricity consumption (kWh/m2, yr) for space cooling, area lighting and total energy for tested overhang ratios, East & West orientations

251

6.8

(c & d)

Electricity consumption (kWh/m2, yr) for space cooling, area lighting and total energy for tested overhang ratios, North & South orientations

252

6.9

Total annual electricity consumption for space cooling and annual electricity consumption for cooling to remove the heat gain from artificial lighting for different overhang ratio tested- East, West, North and South orientations

253

6.10

(a & b)

Incremental energy use (kWh/m2, yr) for cooling, lighting and total energy for tested overhang ratios- East and West orientations

256

6.10

(c & d)

Incremental energy uses (kWh/m2, yr) for cooling, lighting and total energy for tested overhang ratios- North and South orientations

257

6.11

Energy saving percentage for space cooling and area lighting incremental energy use as a function of overhang ratio, East, West, North and South orientations

264

6.12

Energy saving percentage for total incremental energy use as a function of overhang ratio, East, West, North and South orientations

265

7.1

Several design option of external horizontal overhang shading device

284

xxx

LIST OF ABBREVIATIONS

ASEAN - Association of South East Asian Nations

ASEAM - A Simplified Energy Analysis Method

ASHRAE - American Society of Heating, Refrigerating and Air Conditioning Engineers

BC - Base Case

BDL - Building Description Language

BLAST - Building Loads Analysis and System Thermodynamics

CAD - Computer Aided Design

CBIP - Commercial Building Incentive Program

CIBS - Charted Institute of Building Service

CIBSE - Chartered Institution of Building Services Engineers

CIE - International Illumination Commission

COSLAM - Conference of Sri Lankan Malays

CTBUH - Council on Tall Building and Urban Habitat

DBT - Dry Bulb Temperature

DDM - Degree-Day Method

DewPT - Dew Point Temperature

DEU CL - Differential Energy Use (cooling)

DOE - Department of Energy (United States)

DOE.wf - Department of Energy weather file

EC LT - Energy Consumption (lighting)

EC CL - Energy Consumption (cooling)

EC TOT - Energy Consumption (total)

EEM - Energy Efficient Measures

eQUEST - Quick Energy Simulation Tool

GFA - Gross Floor Area

GIA - Gross Internal Area

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HVAC - Heating, Ventilation & Air-Conditioning

HSA - Horizontal Shadow Angle

IB - Intelligent Building

IES - Illuminating engineers society of North America

IES - International Energy Standards

IES - Integrated environmental Solutions

IEU - Incremental Energy Use

IEUCL - Incremental Energy Use (cooling)

IEULT - Incremental Energy Use (lighting)

IEUTOT - Incremental Energy Use (total)

LEO - Low Energy Office

LEED - Leadership in Energy and Environmental Design

MBE - Mean Bias Error

MDD - Modified Degree-Day method

MECM - Ministry of Energy, Communications & Multimedia (Malaysia)

MEWC - Ministry of Energy, Water and Communication (Malaysia)

MS - Malaysian Standards

NFRC - National Fenestration Rating Council

NI - Nebulosity Index

NRA - Net Rentable Area

OHR - Overhang Ratio

OHRé - Overhang Ratio (Side extension é)

OHRfin - Overhang Ratio vertical fins

ORI - Façade Orientation

OTTV - Overall Thermal Transfer Value

PC - Personal Computer

PF - Projection Factor

PSALI - Permanent Supplementary Artificial Lighting of Interiors

PWD - Public Works Department

RMSE - Root Mean Square Error

SHGF - Solar Heat Gain Factor

SHGFv - Solar Heat Gain Factor vertical surface

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SHGFsh - Solar Heat Gain Factor shaded window

SMS - Subang Meteorological Station

SIR - Sun Illuminance Ratio

TMY - Typical Metrological Year

THG - Total Heat Gain

TRY - Test Reference Year

UMNO - United Malaya National Organization

USAID - Unite States Agency for International Development

UTM - Universiti Teknologi Malaysia

VE - Virtual Environment

VSA - Vertical Shadow Angle

WBT - Wet Bulb Temperature

WWR - Window-to-Wall Ratio

WYEC - Weather Year for Energy Calculations

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LIST OF SYMBOLS

A - Surface Area (m2)

α - Absorptance (dimensionless)

A1, A2, A3 - Coefficients of absorptions (constants)

A4, A5, A6 - Coefficients of absorptions (constants)

Acog - Projected area center of glass (m2)

Aeog - Projected area edge of glass (m2)

Aframe - Projected area of frame (m2)

AG - Fraction of window area exposed to the sun (m2)

Ar - Rayleigh scattering coefficient

Asun - Area of window exposed to the sun (m2)

αb - Absorptance of reference glazing for direct beam

αdiff - Absorptance of reference glazing for diffuse radiation

B - Atmospheric extinction coefficient (dimensionless)

β - Solar altitude angle above the horizontal (0)

C - Diffuse sky factor

C1, C2, C3 - Coefficients of transmission (constants)

C4, C5, C6 - Coefficients of transmission (constants)

Cd - Compensation factor for window dirt (DF calculation)

Cf - Compensation factor for frame (DF calculation)

Cg - Compensation factor for glazing (DF calculation)

Cn - Clearness number of the atmosphere (dimensionless)

CR - Cloud Ratio

D - Depth of the horizontal projection (m)

δ - Solar declination angle (0)

d - Horizontal projection of the distance between the awning’s lower corner and its shadow on the vertical wall (m)

DF - Daylight Factor

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Ėdiff,cl - Clear sky diffuse illuminance (lux)

Edsky - Direct illuminance from sky (lux)

Er(ext)sky - External reflected component from sky illuminance (lux)

Er(int)sky - Internal reflected component from sky illuminance (lux)

Eidsun - Internal direct illuminance from sunlight (lux)

Eirsun - Internal reflected illuminance from sunlight (lux)

Eo,sun - Exterior illuminance from sunlight (lux)

Eo,sky - Exterior illuminance from sky (lux)

Ei - Interior illuminance (lux)

Eo - Exterior illuminance (lux)

Et - Equation of time

e - Projection side ways from the window vertical edge (m)

e1 - Length of the shading device over the window (m)

é - Awning width exceeding window width on each side (m)

φ - Latitude of the location (0)

Ffl - Flue loss factor, equipment

Fra - Radiation factor, equipment

Fs - Lighting special allowance factor

Fsg - Angle factor between the surface and the sky

Fss - Angle factor between the surface and the sky

Fu - Light use factor, lighting

Fua - Use factor, equipment

f - Depth of the vertical fin (m)

fr - Fraction of diffuse radiation obstructed by the shading device

γ - Surface solar azimuth (0)

G-value - Total fraction of incident solar energy transmitted (dimensionless)

Gref - Reflectance of the ground

Gsunshade - G-value for corresponding shading device (dimensionless)

Gsystem - G-value for corresponding window system with shading (dimensionless)

Gwindow - G-value for window (dimensionless)

η1, η2 - Regression coefficients for total energy (dimensionless)

Hfen - Height of fenestration (m)

Hi - Inside air enthalpy, (kJ/kg) (dry air)

xxxv

Ho - Outside air enthalpy, (kJ/kg) (dry air)

h - Horizontal projection of the awning (m)

hi - Heat transfer coefficient, inside glazing surface (W/m2 K)

ho - Heat transfer coefficient, outside glazing surface(W/m2 K)

Isc - Solar constant

Io - Extraterrestrial solar radiation (W/m2)

Ibn - Direct beam normal solar radiation (W/m2)

Ibh - Direct beam solar radiation on horizontal surface (W/m2)

Ibv - Direct beam solar radiation on vertical surface (W/m2)

Idiff,h - Diffused solar radiation on horizontal surface (W/m2)

Idiff,v - Diffused sky radiation on vertical surface (W/m2)

IGh - Global irradiance horizontal surface (W/m2)

IGv - Global irradiance vertical surface (W/m2)

Ir - Ground reflected radiation (W/m2)

It,θ - Total horizontal radiation strikes the ground surface (W/m2)

Itot,h - Total solar radiation on horizontal surface (W/m2)

Itot,v - Total solar radiation on vertical surface

Icl,diff - Diffused solar radiation clear sky (W/m2)

İdv - Diffused & reflected radiation on vertical glazing (W/m2)

İbv - Direct beam radiation on vertical plane (W/m2)

Ї - Apparent extraterrestrial irradiance (W/m2)

Ídr - Direct solar radiation transmitted through standard 3mm clear glass

Ídf - Diffused solar radiation transmitted through standard 3mm clear glass Ítot - Total (direct + diffused) solar radiation transmitted

through standard 3mm clear glass

ϕ - Awning slope (0)

K - Luminous efficacy (lm/W)

KB - Beam luminous efficacy (lm/W)

Kcc - Cloud cover ratio

KD - Diffused luminous efficacy (lm/W)

KG - Global luminous efficacy (lm/W)

k - Fraction of diffuse radiation obstructed by the shading device

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L - Awning length (m)

λ1 - Regression coefficient for lighting energy (dimensionless)

L edge - Length of window frame edge (m)

Lloc - Longitude of the location (in degree)

Lstd - Standard meridian for the local time zone (Longitude of the time zone)

Ltot - Total Length (m)

m - Optical air mass

µ1, µ2 - Regression coefficients for cooling energy (dimensionless)

N - Cloud amount

Ni - Inward flowing fraction of the absorbed radiation

No - Number of people

Nt - Cloud type

n - Daily sunshine duration

no - Maximum possible sunshine duration

pa - Atmospheric pressure

Q - Ventilation air flow (L/s)

θ - Incident angle (0)

θh - Angle of incidence on horizontal surface (0)

θv - Angle of incidence on vertical surface (0)

Qc - Conduction heat flow rate (w)

Qcl - Cooling energy use (W/m2)

Qel - Heat gain from electric lighting (w)

Qeq - Appliances heat gain (w)

Qi - Occupants heat gain (w)

Qs,win - Total solar heat gain flow rate, window (w)

Qv - Convection heat flow rate (w)

Qwin - Thermal heat gain, window (W/m2K)

ρ - Reflectance (dimensionless)

Rgap - Thermal resistance of gap between panes (m2K/W)

Rgl - Thermal resistance of glass pane (m2K/W)

Rsi - Internal surface resistance (m2K/W)

Rse - External surface resistance (m2K/W)

Rtot - Total thermal resistance (m2K/W)

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R2 - Coefficient of determination

S - Relative sunshine duration

SC - Shading coefficient

SC clearglass - Shading coefficient of clear glass

SCshadingdevice - Shading coefficient of shading device

SC net - Net shading coefficient for partially shaded window

Sdf - Sky diffusive factor

Sec - Solar extinction coefficient

∆T - Temperature difference (0C)

τ - Τransmittance (dimensionless)

Td - Dew point temperature (0C)

Tdt - Out door dry-bulb temperature (0C)

Tsol - Local solar time

Tstd - Local standard time

Twt - Out door wet-bulb temperature (0C)

τa - Secondary heat transmittance (dimensionless)

τb - Transmittance of reference glazing for direct beam (dimensionless)

τdiff - Transmittance of reference glazing for diffuse radiation

ti - Daily mean indoor temperature (0C)

to - Daily mean out door temperature (0C)

U - Thermal transmittance value (W/m2K)

Ucog - Thermal transmittance center of glass (W/m2K)

Ueog - Thermal transmittance edge of glass (W/m2K)

Uframe - Thermal transmittance frame (W/m2K)

UPD - Average lighting unit power density (W/m2)

Uwin - Thermal transmittance of window (W/m2K)

Vd - Wind direction

Vs - Wind speed

v - Vertical projection of the awning/ horizontal shading device (m)

W - Total light wattage

ω - Solar hour angle (0)

Wawn - Width of the awning (m)

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Wfen - Width of fenestration (m)

Wo - Outside humidity ratio, kg (water)/ kg (dry air)

Wi - Inside humidity ratio, kg (water)/ kg (dry air)

ψedge - Linear heat transmittance coefficient (W/mK)

ζ - Surface tilt angle (0)

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LIST OF APPENDICES

APPENDIX TITLE PAGE

A Summary of Energy Related Research 306

C Summary of High-Rise Office Building and Energy Use Review

C1. Office Buildings Energy Data Base

Kuala Lumpur, Malaysia

309

C2. South East Asian Office Building

Information

312

C3. Design of Shading Device Considering the

Windows Solar Angle Dependent Properties: With Special Reference to Kuala Lumpur Hot and Humid Tropical Climates

315

D

Review of Computer Simulation Programs

329

E

Simulation Data and Results

E1. Sample of Input Data

333

E2. Summary: Direct and Diffused Incident

Solar Radiation and Transmitted Heat Gains

338

E3. Summary: Work Plane Illuminance at

Ref.Pt:01 and Ref.Pt:02

344

F

Summary Building Energy Use

F1. Summary: Building Cooling Load Data

347

F2. Summary: End Use Energy Consumption

Data with Natural-light utilization

350

Optimum overhang geometry for high rise office building energy saving in tropical climates

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