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nnar033Typewritten TextVIKRAM ADITYA NARLA

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Optimizingspecificenergyperformanceforaresidenceincompositeclimate

6 / 3 0 / 2 0 1 1

VikramAdityaNarlaA thesis submitted in fulfilment of the requirements for the

master of Architecture The University of Auckland 2011

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Abstract Artificial cooling is becoming a common and unavoidable feature in residential buildings in India. The

associated problems of cooling on energy demand are well known. Climate responsive techniques

can aid to reducing energy for cooling and enhancing the efficiency in energy use. In that context the

purpose of this research is to investigate the effect on cooling loads by varying material configurations

in the envelope design of specific typology of domestic dwellings in Hyderabad (a city in India with

composite climate).

Post occupancy evaluation on existing dwellings of a particular gated residential enclave was

conducted to assess the problems regarding passive heat gains. The study included observational

evaluation of site conditions and physical measurements of temperature within the dwellings.

Commonalities observed from the case study in the dwellings help set up base case dwelling model

with variables obtained from the same dwelling. Using computer simulations techniques, isolated

building elements with variations in Material configurations were tested and compared with each other

to find which was most beneficial to reduce the cooling load.

Recommendations to the specific envelope features supported by the findings are made to enable the

groups involved in residential construction practices in Hyderabad make informed choices for

developing enhanced residential real-estate.

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Acknowledgement I would like to express my humblest gratitude to the people, who I had the good fortune to encounter,

while experiencing the research process.

First, to my supervisor Dr.Hugh Byrd, who helped me in the possibility of completing my thesis under

testing conditions I would not, had it not been for his advice on my work, have completed this thesis.

His patient supervision and valuable comments were of great help to me.

To Dr. Rosangela Tenorio, who in her stint with me, helped me establish the foundation for this thesis.

To Dr. Paola Leardini, who, despite her busy schedule always made some time for me to clarify my

doubts.

To Najah Alwi, for enriching my knowledge on a particular software used in this thesis with her rain of

questions.

To Malti Surpur Aravind, for steering my thoughts to clarity during those moments my thesis drove me

into potholes of confusion.

To my dearest friend for seven and half years till date, B.G Srirama who kept me working on track

whenever he felt I derailed.

And last but not the least to them who I am forever fortunate of being the son too, my parents, who in

their own implicit way have motivated me throughout this journey.

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Table of Contents Abstract ................................................................................................................................................ 2

Acknowledgement ................................................................................................................................ 3

Table of Contents ................................................................................................................................. 4

List of Figures ..................................................................................................................................... 10

1 Introduction ................................................................................................................................. 14

1.1 Research Hypothesis: ......................................................................................................... 15

1.2 Aims and Objectives: .......................................................................................................... 15

1.3 Research scope and limitations: ......................................................................................... 15

1.4 Significance of the research: ............................................................................................... 16

2 Energy crisis ............................................................................................................................... 17

2.1 Global context ..................................................................................................................... 17

2.2 Depleting fossil fuel supply ................................................................................................. 17

2.3 Energy issues: Indian context ............................................................................................. 18

2.3.1 Policy changes: ........................................................................................................... 19

2.3.2 Building Codes ............................................................................................................ 19

2.4 Energy use by building sector (residential sector) ............................................................... 20

2.5 Electricity use in Buildings: ................................................................................................. 21

3 Climate of the region .................................................................................................................. 23

3.1 Hot and Dry ........................................................................................................................ 23

3.2 Warm and Humid ................................................................................................................ 24

3.3 Moderate ............................................................................................................................ 25

3.4 Cold and Sunny .................................................................................................................. 25

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3.5 Composite climatic zone ..................................................................................................... 26

3.6 Climate change ................................................................................................................... 29

3.6.1 Climate change in India............................................................................................... 30

3.7 Growth in Air-conditioning: .................................................................................................. 34

3.8 Views on energy efficiency in India: .................................................................................... 35

3.9 Concluding comment: ......................................................................................................... 36

4 Climate responsive design .......................................................................................................... 37

4.1 Site parameters .................................................................................................................. 38

4.1.1 Landform and its orientation ........................................................................................ 38

4.1.2 Vegetation pattern ....................................................................................................... 38

4.1.3 Water bodies ............................................................................................................... 38

4.1.4 Street width and orientation ........................................................................................ 39

4.1.5 Open spaces and built form ........................................................................................ 39

4.2 Plan form and orientation .................................................................................................... 39

4.2.1 Building configuration .................................................................................................. 39

4.2.2 Building orientation ..................................................................................................... 39

4.3 Building envelope ............................................................................................................... 40

4.3.1 Roof: ........................................................................................................................... 40

4.3.2 Wall type: .................................................................................................................... 40

4.3.3 Openings and Fenestrations: ...................................................................................... 40

4.3.4 Shading and textures: ................................................................................................. 41

5 Hyderabad and its residential building industry: .......................................................................... 42

5.1 Profile of the city ................................................................................................................. 42

5.2 Physical Characteristics ...................................................................................................... 43

5.3 The residential building Industry of Hyderabad ................................................................... 43

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5.4 Gated residential enclaves: ................................................................................................. 46

5.5 Recent accounts in residential real-estate in Hyderabad .................................................... 47

5.5.1 Influences during development ................................................................................... 49

5.5.2 Penetration of Gated residential enclaves (Gated communities) ................................. 49

5.6 The dwelling format: ........................................................................................................... 51

5.7 Construction methods ......................................................................................................... 52

6 Thermal Performance ................................................................................................................. 53

6.1 Thermal comfort .................................................................................................................. 54

7 Methodology ............................................................................................................................... 55

7.1 Case study method ............................................................................................................. 55

7.2 Simulation Method: ............................................................................................................. 58

7.3 Parameters of base case: ................................................................................................... 60

7.3.1 Description of Parameters Investigated: ..................................................................... 60

8 Case study ................................................................................................................................. 74

8.1.1 Description of Buildings: .............................................................................................. 74

8.1.2 Case study findings ..................................................................................................... 75

8.2 Site settings ........................................................................................................................ 82

8.3 Plan from and Orientation: .................................................................................................. 83

8.4 Envelope features ............................................................................................................... 83

9 Simulation results ....................................................................................................................... 84

9.1 Case set 1 effect of orientation on performance ................................................................. 84

9.1.1 Base case with West orientation ................................................................................. 84

9.1.2 Base case with south orientation................................................................................. 85

9.1.3 Base case with East orientation .................................................................................. 87

9.1.4 Base case with North Orientation ................................................................................ 88

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9.2 Case set 2 effect on performance with changes in roof material configuration .................... 90

9.2.1 R.C.C roof with Mudphuska ........................................................................................ 90

9.2.2 R.C.C roof with bitumen felt ........................................................................................ 92

9.2.3 R.C.C roof with Poly urethane foam ............................................................................ 94

9.3 Case set 3 effect on performance with changes in Wall material configuration ................... 96

9.3.1 Concrete Block wall .................................................................................................... 96

9.3.2 Auto-claved Cellular Concrete block wall .................................................................... 98

9.3.3 Brick wall with expanded polystyrene insulation ........................................................ 100

9.4 Case set 4 effects on performance with combination approach ........................................ 102

9.4.1 R.C.C roof with Mudphuska and concrete block wall ................................................ 102

9.4.2 R.C.C roof with Mudphuska and Auto-claved concrete block wall ............................. 104

9.4.3 R.C.C roof with Mudphuska and brick wall with Polystyrene ..................................... 106

9.4.4 R.C.C roof with bitumen felt and concrete block wall ................................................ 108

9.4.5 R.C.C roof with bitumen felt and Autoclaved cellular concrete block wall .................. 110

9.4.6 R.C.C roof with bitumen felt and Brick wall with Polystyrene insulation ..................... 112

9.4.7 R.C.C roof with Polyurethane foam and Concrete block wall .................................... 114

9.4.8 R.C.C roof with Polyurethane foam and Autoclaved cellular Concrete block wall ..... 116

9.4.9 R.C.C roof with Polyurethane foam and Brick wall with Polystyrene insulation ......... 118

9.5 Case set 5 effects on performance with change in surface colour .................................... 120

9.5.1 Base case with external paint - 0.6 Reflectance ........................................................ 120

9.5.2 Base case with external paint - 0.7 Reflectance ........................................................ 122

9.5.3 Base case with external paint - 0.8 Reflectance ........................................................ 124

9.5.4 Insulated case with external paint - 0.6 Reflectance ................................................. 126

9.5.5 Insulated case with external paint - 0.7 Reflectance ................................................. 128

9.5.6 Insulated case with external paint - 0.8 Reflectance ................................................. 130

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9.6 Summary of results ........................................................................................................... 131

9.6.1 Case set 1 Effect on cooling load based on orientation ............................................. 131

9.6.2 Case set 2 Effect on cooling load with roof variables ................................................ 131

9.6.3 Case set 3 Effect on cooling load with wall variables ................................................ 131

9.6.4 Case set 4 Effect on cooling load based on combination approach .......................... 131

9.6.5 Case set 5 Effect on cooling load with surface colour variables ................................ 132

10 Discussion and conclusion ................................................................................................... 133

10.1 Orientation: ....................................................................................................................... 133

10.2 Roof (R1, R2 and R3) ....................................................................................................... 134

10.3 Wall (W1, W2 and W3) ..................................................................................................... 135

10.4 Combination approach R1 -W1, W2 and W3: ................................................................... 136

10.5 Combination approach R2 -W1, W2 and W3: ................................................................... 137

10.6 Combination approach R3 -W1, W2 and W3: ................................................................... 138

10.7 Colour (reflectance): ......................................................................................................... 139

10.8 Conclusion ........................................................................................................................ 139

10.9 Recommended roof systems: ........................................................................................... 140

10.10 Recommended wall systems: ....................................................................................... 141

10.11 Limitations to insulation: ................................................................................................ 141

11 Further considerations: ......................................................................................................... 142

11.1 Thickness and shape: ....................................................................................................... 142

11.2 Glazing: ............................................................................................................................ 142

11.3 Future research: ............................................................................................................... 142

Bibliography and References ........................................................................................................... 144

Appendix .......................................................................................................................................... 146

Case set 1 Effect of Orientation on cooling load ........................................................................... 146

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Case set 2 Effect on cooling with varying roof material ................................................................. 150

Case set 3 Effect on cooling with varying wall material ................................................................. 153

Case set 4 Effect on cooling by combining wall and roof material ................................................ 156

Case set 5 Effect on cooling by combining wall and roof material ................................................ 165

Temperature log Of House no 39 from 13th June to 15th June 2010 .............................................. 171

Temperature log Of House no 64 from 13th June to 15th June 2010 ............................................. 172

Temperature log Of House no 41from 27th June to 29th June 2010 .............................................. 173

Temperature log Of House no 64 from 27th June to 29th June 2010 ............................................. 174

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List of Figures

Figure 1: trends in Commercial energy production in India Source:(planningcommission 2002) ........ 18Figure 2: level of Urbanization since the year 1970 -2005 Source: (Singh and Michaelowa 2004) ..... 21Figure 3: Annual electricity consumption or residential and commercial buildings in India

Source:(Singh and Michaelowa 2004) ................................................................................................ 22Figure 4: Appliance penetration levels in Urban households .............................................................. 22Figure 5: Map of India showing climatic zones (NBC 2005)................................................................ 23Figure 6: Classification of climate adapted from (NBC 2005) ............................................................. 26Figure 7: prevailing wind rose of Hyderabad ...................................................................................... 28Figure 8: Climate summary and degree of heating/cooling hours ....................................................... 28Figure 9: Monthly diurnal averages and Daily conditions. ................................................................... 29Figure 10: Changes in temperature sea level and northern hemisphere snow cover Source: statistics

from Intergovernmental panel for climate change IPCC. Retrieved

from:http://www.ipcc.ch/publications_and_data/ar4/wg1/en/figure-spm-3.html ................................... 30Figure 11 Temperature anomaly Source:(Lal et al. 2001) .................................................................. 31Figure 12 total heat wave mortality rates (Akpinar-Ferrand and Singh 2010) ..................................... 32Figure 13 Spatial distribution of heat waves in India between 1911 and 1999 (Akpinar-Ferrand and Singh

2010). .................................................................................................................................................. 33Figure 14 Increased Air-condition sales in India (Akpinar-Ferrand and Singh 2010) .......................... 34Figure 15: Map of Andhra Pradesh ..................................................................................................... 42Figure 16: total built up area of MCH Building permissions in Sq.m ................................................... 44Figure 17: View of Mumbai from the sea http://www.goiit.com/posts/list/0/community-shelf-the-crown-

to-mumbai-s-skyline-974295.htm ....................................................................................................... 44Figure 18: View of Auckland from sea Source: http://www.planetware.com/picture/auckland-nz-

nz689.htm retireved on 14-0602011 16:46 ........................................................................................ 45Figure 19: Gated residential enclave: multifamily residence. Source:

http://www.srikrishnagroup.com/realestate_New/krishegardens.html Retrieved on: 14-06-2011 ........ 46Figure 20: Ariel view of Gated residential enclave in mixed format. Source: http://maps.google.co.nz/

key word IJM Rain tree park, Retrieved on: 14-06-2011 17:22pm ...................................................... 46Figure 21: Gated residential enclave as single family dwellings. Source: http://hyderabad.olx.in/villas-

for-sale-near-hightech-city-hyderabad-a-p-iid-193249622, Retrieved on 14-06-2011 17:28 pm ......... 47Figure 22 Distribution of Urban households by type of dwellings ........................................................ 48Figure 23: Map of India with case study location ................................................................................ 55Figure 24 Entry view of Tulsi Gardens (Gated residential enclave) .................................................... 56Figure 25: Escort Junior Data logger .................................................................................................. 57Figure 26: North West view of Ecotect simulation Model .................................................................... 59

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Figure 27: South west view of Ecotect simulation model .................................................................... 59Figure 28 base case parameters ........................................................................................................ 60Figure 29: Orientation parameters ...................................................................................................... 62Figure 30: Roof option R1parameters ................................................................................................ 63Figure 31: Roof option R1 material properties .................................................................................... 63Figure 32: Roof option R2 parameters ............................................................................................... 64Figure 33: Roof option R2 material properties .................................................................................... 64Figure 34: Roof option R3 parameters ............................................................................................... 65Figure 35: Roof option R3 Material properties .................................................................................... 65Figure 36: Wall option W1 parameters ............................................................................................... 66Figure 37: Wall option W1 material properties .................................................................................... 66Figure 38: Wall option W2 parameters ............................................................................................... 67Figure 39: Wall option W2 material properties .................................................................................... 67Figure 40: Wall option W3 Parameters ............................................................................................... 68Figure 41 Wall option W2 Material properties ..................................................................................... 68Figure 42: Combination option R1W1 parameters .............................................................................. 69Figure 43: Combination option R1W2 parameters .............................................................................. 69Figure 44: Combination option R1W3 parameters .............................................................................. 69Figure 45: Combination option R2W1 parameters .............................................................................. 70Figure 46: Combination option R2W2 parameters .............................................................................. 70Figure 47: Combination option R2W3 parameters .............................................................................. 70Figure 48: Combination option R3W1 ................................................................................................. 71Figure 49: Combination option R3W2 ................................................................................................. 71Figure 50: Combination option R3W3 ................................................................................................. 71Figure 51: Base case colour option 0.6 reflectance for ....................................................................... 72Figure 52: Base case colour option 0.7 reflectance ............................................................................ 72Figure 53: Base case colour option 0.8 reflectance ............................................................................ 72Figure 54: Insulated case colour option 0.6 reflectance ...................................................................... 73Figure 55: Insulated case colour option 0.7 reflectance ...................................................................... 73Figure 56: Insulated case colour option 0.8 reflectance ...................................................................... 73Figure 57: Ariel view of Tulsi Gardens ................................................................................................ 74Figure 58: Images of House no 64 ..................................................................................................... 74Figure 59 typical floor plans of the selected dwelling units ................................................................. 75Figure 60 Temperature readings of house no 39 13th June to 15th June (Refer appendix) ................. 76Figure 61 temperature readings of house no 64 13th June to 15th June 2010 (Refer appendix) .......... 77Figure 62 Temperature reading of House no 41 from 27th June to 29th June 2010 (Refer appendix) .. 78Figure 63 Temperature readings of house no 64 from 27th June to 29th June 2010 (Refer appendix) 79Figure 64 electricity bill readings of House no 39 from 01 March 2007 to 01 March 2011 .................. 80Figure 65 Electricity bill readings of house no 64 from 01 March 2007 to 01 March 2011 .................. 81

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Figure 66: base case simulation model oriented west ........................................................................ 84Figure 67: Monthly heating/cooling loads of west orientation (refer appendix A1 for Monthly loads) .. 84Figure 68: Monthly heating/cooling graph of west orientation ............................................................. 85Figure 69: Base case simulation model oriented south ...................................................................... 85Figure 70: Monthly heating/cooling loads of south orientation (refer appendix A2 for Monthly loads) . 86Figure 71: Monthly heating/cooling graph of south orientation ............................................................ 86Figure 72: Base case simulation model oriented east ........................................................................ 87Figure 73 Monthly heating/cooling loads of east orientation (refer appendix A3 for Monthly loads) .... 87Figure 74: Monthly heating/cooling graph of east orientation .............................................................. 88Figure 75: Base case simulation model oriented north ....................................................................... 88Figure 76: Monthly heating/cooling loads of north orientation (refer appendix A4 for Monthly loads) . 89Figure 77: Monthly heating/cooling graph of north orientation ............................................................ 89Figure 78: Monthly heating/cooling loads of R1 (refer appendix B1 for Monthly loads) ...................... 90Figure 79: Monthly heating/cooling Graph of R1 ................................................................................ 91Figure 80: Monthly heating/cooling loads of R2 (refer appendix B2 for Monthly loads) ...................... 92Figure 81: Monthly heating/cooling graph of R2 ................................................................................. 93Figure 82: Monthly heating/cooling loads of R3 (refer appendix B3 for Monthly loads) ...................... 94Figure 83: Monthly heating/cooling graph of R3 ................................................................................. 95Figure 84: Monthly heating/cooling loads of W1 (refer appendix C1 for Monthly loads) ...................... 96Figure 85: Monthly heating/cooling graph of W1 ................................................................................ 97Figure 86: Monthly heating/cooling loads of W2 (refer appendix C2 for Monthly loads) ...................... 98Figure 87: Monthly heating/cooling graph of W2 ................................................................................ 99Figure 88: Monthly heating/cooling loads of W3 (refer appendix C3 for Monthly loads) .................... 100Figure 89: Monthly heating/cooling graph of W3 .............................................................................. 101Figure 90: Monthly heating/cooling loads of R1W1 (refer appendix D1 for Monthly loads) ............... 102Figure 91: Monthly heating/cooling graph of R1W1 .......................................................................... 103Figure 92: Monthly heating/cooling loads of R1W2 (refer appendix D2 for Monthly loads) ............... 104Figure 93: Monthly heating/cooling loads of R1W2........................................................................... 105Figure 94: Monthly heating/cooling loads of R1W3 (refer appendix D3 for Monthly loads) ............... 106Figure 95: Monthly heating/cooling graph of R1W3 .......................................................................... 107Figure 96: Monthly heating/cooling loads of R2W1 (refer appendix D4 for Monthly loads) ............... 108Figure 97: Monthly heating/cooling graph of R2W1 .......................................................................... 109Figure 98: Monthly heating/cooling loads of R2W2 (refer appendix D5 for Monthly loads) ............... 110Figure 99: Monthly heating/cooling graph of R2W2 .......................................................................... 111Figure 100: Monthly heating/cooling loads of R2W3 (refer appendix D6 for Monthly loads) ............. 112Figure 101: Monthly heating/cooling graph of R2W3 ........................................................................ 113Figure 102 Monthly heating/cooling loads of R3W1 (refer appendix D7 for Monthly loads) .............. 114Figure 103: Monthly heating/cooling graph of R3W1 ........................................................................ 115Figure 104 Monthly heating/cooling loads of R3W2 (refer appendix D8 for Monthly loads) .............. 116

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Figure 105: Monthly heating/cooling graph of R3W2 ........................................................................ 117Figure 106: Monthly heating/cooling loads of R3W3 (refer appendix D9 for Monthly loads) ............. 118Figure 107: Monthly heating/cooling graph of R3W3 ........................................................................ 119Figure 108: Monthly heating/cooling loads of Base case with 0.6 reflectance (refer appendix E1 for

Monthly loads) .................................................................................................................................. 120Figure 109: Monthly heating/cooling graph of Base case with 0.6 reflectance .................................. 121Figure 110: Monthly heating/cooling loads of Base case with 0.7 reflectance (refer appendix E2 for

Monthly loads) .................................................................................................................................. 122Figure 111: Monthly heating/cooling graph of Base case with 0.7 reflectance .................................. 123Figure 112: Monthly heating/cooling loads of Base case with 0.8 reflectance (refer appendix E3 for

Monthly loads) .................................................................................................................................. 124Figure 113: Monthly heating/cooling graph of Base case with 0.8 reflectance .................................. 125Figure 114: Monthly heating/cooling loads of Insulated case with 0.6 reflectance (refer appendix E4

for Monthly loads) ............................................................................................................................. 126Figure 115: Monthly heating/cooling graph of insulated case with 0.6 reflectance ............................ 127Figure 116: Monthly heating/cooling loads of Insulated case with 0.7 reflectance (refer appendix E5

for Monthly loads) ............................................................................................................................. 128Figure 117: Monthly heating/cooling graph of insulated case with 0.7 reflectance ............................ 129Figure 118: Monthly heating/cooling loads of Insulated case with 0.8 reflectance (refer appendix E6

for Monthly loads) ............................................................................................................................. 130Figure 119: Monthly heating/cooling graph of insulated case with 0.7 reflectance ............................ 130Figure 120: Comparative graph of cooling loads between west, south, east and north orientation ... 133Figure 121: Comparative graph of cooling loads between Base case, R1, R2 and R3 ..................... 134Figure 122: Comparative graph of cooling loads between Base case, W1, W2 and W3 ................... 135Figure 123: Comparative graph of cooling loads between base case, R1W1, R1W2 and R1W3 ..... 136Figure 124: Comparative graph of cooling loads between base case, R2W1, R2W2 and R2W3 ..... 137Figure 125: Comparative graph of cooling loads between base case, R3W1, R3W2 and R3W3 ..... 138Figure 126: Comparative graph of cooling loads between base and insulated case ......................... 139

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1 Introduction

Following the economic reforms in India two decades ago, there came about tremendous growth in its

economy. Apart from inviting foreign direct investments it offered opportunities to set up multinational

firms in India. This growth also accompanied rapid urbanization due to the opportunities and better

livelihoods. Rapid urbanization causes overcrowding leading to housing shortage and also increases

the energy demand within cities. Hyderabad faces the same fate as, Bombay and Bangalore and

other metros across India.

Since the starting of this decade, Hyderabad became established as the hub of the Information

technology sector by hosting large multinational companies within its region. Presently, the

information technology, aside from Pharmaceutical industry, has become the major economic

contributor to city and also to the state of Andhra Pradesh. The foreign investment bought by these

companies set of informal markets which fuelled the real-estate industry specifically, the residential

sector. To meet the enormous demand induced by the impending urbanization process, residential

settlements were constructed rapidly.

One of the many comfort providing urban residential forms that became prevalent during this time is

the gated residential enclave. Gated residential enclaves have become popular choice of residence

as they have the advantages of living independently yet being a part of a community within the safety

of a fence and because, people are freed from taking up the task of the construction process. These

enclaves are usually preferred by the economically comfortable middle class, who share a majority of

the population in the cities of India. The aim of the developer was to satisfy the consumer by providing

visually pleasant buildings in seemingly natural environs and produce it in short time to overcome

competitions. Hence, the design of these may or may not follow climatic parameters in the process of

rapid deliverance.

Another aspect of comfort that is popular among this group is artificial cooling. Subsidised electricity

rates, economic wellbeing and subsequent social lifestyle changes have given rise to artificial cooling

and the requirement of Air-conditioners have shifted from a single room to more than one. Climate

also is the chief contributor to this growth. India has a mixture of various climatic zones ranging from

arid, temperate, moderate and cold, Hyderabad which experiences the composite climate consists of;

hot summers, warm humid monsoon and cold winters. None of the seasons last longer than six

months, hence the term composite climate. In the summer months, people experience high thermal

stress as day temperatures reach 40DegC and artificial cooling is required. Artificial cooling has its

impact on energy consumption, but because of the climatic situation it is one such feature that cannot

be entirely eliminated.

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Electricity is one of the clean energy carriers that are demanded in the rapidly urbanizing Hyderabad.

However, electricity shortages are a common occurrence and summers pose a problem because of

peak loads. The growing use of Air-conditioners is known to cause incremental stress on peak loads.

Expanding the electric utilities is a strategic response of the concerned authorities. However,

electricity in India is largely produced by coal. Problems associated with the use of coal are well

known. Continuous use of this fossil fuel could lead to serious and unavoidable environmental

impacts.

Climate responsive techniques are a relevant solution to lessen the associated problems of cooling.

This thesis, therefore, focuses on the important aspects of the built form of dwellings in a specific

gated residential enclave that can contribute to reduction of energy use.

1.1 Research Hypothesis:

There is potential energy saving in residential dwellings by adopting building elements with better

thermal performance

1.2 Aims and Objectives:

The research took its origins from the general observations the author made on the presence of air

conditioners in all the new and existing constructions of residential settlements in Hyderabad. In that

context two questions formed whether the current residential design practices allowed better thermal

performance? This question leads to the post-occupancy evaluation to monitor the existing dwelling

thermal performance. Study and evaluation of the building design in the climatic context, the

investigation into current energy policies concerned with energy use in residential buildings and also

The objectives that developed from the questions are:

Identifying, understanding and discussing the existing design approaches.

To investigate the effects of variable design features on the cooling load of the building.

1.3 Research scope and limitations:

The research is focussed towards one Gated residential enclave. Gated residential enclaves are

notable urban settlement forms in the city of Hyderabad and their existence is a resultant of comfort

aspirations of the economically comfortable middle class and rich societies. They appear in various

formats ranging from double storied single family residential units to multifamily units arranged within

defined property limits.

The type of residential settlement forms are many and differ largely by the economic situations. In the

context gated residential enclaves offer better opportunity for the study as they are notably prevalent,

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they are designed with established programmatic configurations based on the esoteric philosophies of

Vaastu (an Indian counterpart of the Chinese Feng Shui). This thesis is not investigating the

programme configuration aspects of the dwelling, so Vasstu which is the determinant of such is only

being discussed as a form of commonality in this settlement type.

Under the condition, the case study was conducted. The gated residential enclave that has been

selected for the study was completed in the year 2005 when the demand for such settlement type was

in its nascent stages.

Investigations carried out in this thesis are limited to the effects of variable changes to the wall and

roof material configurations under conditioned states. In addition, the effect of orientation on the

building is also looked at through the simulations. The results obtained are directed to only establish

the importance of upgrading to enhance the overall thermal performance and address cooling energy

demand. This research does not investigate the effects of other heat gain systems such as windows

and shadings. In addition the research also does not investigate the effects of Hybrid cooling

designs, which involve a combination of Passive designs and supplemental air-conditioning systems.

There are no national standards established for the energy use of residential buildings so comparison

is done in between different simulated cases.

An important feature to evaluate cooling loads is the thermal comfort temperatures. The research

uses the comfort temperature ranges indicated in the National building code of India. The period of

data collection and case study duration was limited to 2 weeks in total on account of cost and allowed

travel time away from the university. The weather files used in the simulation were obtained from built

in weather data for the chosen city.

1.4 Significance of the research:

The construction industry is largely influenced by the dynamics of market and subsequently the

developers and architects function as dictated by the current demands. The demand may be so rapid

that climate responsive strategies may not be included into the real-estate products, produced by

these developers.

Through the study the research aims to derive solutions to supplement existing strategies that enable

the developers and architects to make informed choices for their real-estate products.

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2 Energy crisis 2.1 Global context

The awareness level of depleting fossil fuels and energy crisis allied with global warming has been

growing rapidly around the world. However, the present state of energy issues takes its origins from

the 1970s oil crisis, which led to the realization of the limits of energy availability.

One of mankinds primary resources is energy. It is essential both to facilitate production and for its

contribution to quality of life through the services it renders- heating/cooling, light, mobility, personal

comfort and leisure. Majority of energy consumed comes from exhaustible sources, primarily in

the form of fossil fuels. It cannot be denied that the discovery and utilization of fossil fuels has

contributed to the development of mankind. However, the overuse of an inexhaustible source such as

fossil fuels has led to the consequence of severe problems like global warming and environmental

degradation.

2.2 Depleting fossil fuel supply

There have been many predictions on the amount of time left for fossil fuels to diminish. None of

which have a provided a positive or reliable results. However, according to International energy

agency it has been estimated that reserves of oil coal and gas will deplete around 43, 184 and 64

years respectively. The International Energy Agency states Fossil fuels remain the dominant sources

of energy worldwide, accounting for 77% of the demand increase in 2007-2030. Although oil

demand is expected to drop by 2.2% in 2009 as a whole, following a drop of 0.2% in 2008, it is

projected to recover from 2010 as the world economy pulls out of recession, rising from around 85

million barrels per day in 2008 to 105 mb/d in 2030, an increase of around 24%. In 2007-2030,

demand for coal grows by 53% and demand for natural gas by 42% (Tanaka 2009).

Seeking development is a necessity to all nations, both industrialised and developing, in the track of

progress. It is a fact that the majority of global energy consumption is accounted by the industrialised

nations. However, developing or emerging nations are also consuming energy in the process of their

growth. India and China for example, currently in a fast track of economic progress, will probably have

an escalated demand in energy. Energy is the essential tool for the development and both

industrialised and developing nations will not stop seeking it. A continued approach in this manner

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without balance can expect the depletion date to be even sooner. Sustainable approaches to such

issues will play crucial roles for continued prosperities.

2.3 Energy issues: Indian context

India is the largest democracy of the world, it is a political leader among developing nations. It is the

most populous nation after china with over one billion people across various regions under different

climate. The energy consumption, economic growth and population are related. According to

discussions of the clean development mechanism strategies;

GDP (Gross Domestic Product) grew at an average rate of 4.9% per year in the past three decades until 1990. Significant economic reforms in 1991 spurred economic activities leading to an average growth rate of 6.7% during 199296. The South-East Asian economic crisis in 1997 put a brake on the accelerating growth rate, though in 1998 the economy revived, averaging 6.1% from 1997 to 2000. India ranks sixth in the world in terms of energy demand accounting for 3.5 % of world commercial energy demand in 2001. With a GDP growth rate of 8 % set for the Tenth Five- Year Plan (2001 2006), the energy demand is expected to grow at 5.2 %. Still, at 479 kg of oil equivalent (kgoe), annual per capita energy consumption is low even compared to other developing countries(Singh and Michaelowa 2004).

The country has seen significant growth in total energy use during the last five decades, with a shift

from non-commercial to commercial sources of energy. Accordingly, the production of commercial

sources of energy has increased significantly. The following table indicates the commercial energy

production.

Figure 1: trends in Commercial energy production in India Source:(planningcommission 2002)

Observing the pattern of energy production in India, coal and oil are at 52 per cent and 33 per cent

respectively with natural gas, hydro and nuclear contributing to the balance. Nearly 62 percent of

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power generation is from coal fired thermal power plants and 70 per cent of the coal produced every

year in India has been used for thermal generation. Energy consumption in India is expected to have

more than doubled by 2020 to meet development aspirations.

In the same report the authors have stated, International concern for rising anthropogenic greenhouse gas (GHG) emissions and potential dangerous consequences of global climate change led to negotiation of the United Nations Framework Convention on Climate Change (UNFCCC) during the Earth summit in June 1992, signed and ratified by India. Indian per capita CO2 emissions averaged 1/12th of high-income countries in the 1990s. In fact, per capita emissions in India were approximately half of those of low and middle-income countries for the same period. While home to 17% of the worlds population, India only has a 5% share of world GHG emissions. Still it ranks 5th in the world after the U.S., China, Russia, and Japan (Singh and Michaelowa 2004).

2.3.1 Policy changes: The union government in collaboration with many international agencies have attempted to move

towards efficient and optimised energy utilization with the inherent view to rectify the problems

concerned with GHG emissions. However, for many years, efforts to finance energy efficiency and

conservation measures have bypassed the building sector(Singh and Michaelowa 2004). This is so

because extensive research concerning energy use was never documented for the building sector.

2.3.2 Building Codes The establishment of energy conscious building code (ECBC 2005) by the Bureau of energy

efficiency India (BEE) is significant step towards addressing the challenges of sustainability. However,

the codes are applicable to building with a connected load of 500kv; this implies that residential

buildings are not included and the codes are only recommended (ECBC 2005). This limitation is due

to the fact that the residential dwellings differ largely by economic situations. Also, the perception of

higher costs with the employment of energy efficient strategies has limited the necessary changes.

This is also agreed by the authors(Singh and Michaelowa 2004) who in their discussion papers have

stated the following the new energy conservation act for efficient use of energy in various

establishments accounts for the energy efficiency in commercial sector, but the residential sector is

still not properly addresses. In normal course of construction, the usage of insulation and efficient

glazing system is still very limited and the benefits of employing energy efficiency measures have still

not percolated among masses.

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2.4 Energy use by building sector (residential sector)

Energy use in Indian residential buildings is the highest amongst Asia pacific partnership countries

(Indraganti 2010)

The building sector contributes significantly to the incremental demand of energy by consuming

around 40 % of the total primary energy consumption. The Indian residential sector consumes

200,708 mtoe (million tonnes of oil equivalent) which represents 11% of the worlds energy

consumption in the residential sector (www.earthtrends.org 2003).

In Indian households energy is mainly used for cooking, lighting and heating/cooling. Heating/cooling

is region and climate specific. A major portion of energy demand in this sector is met through non-

commercial fuels such as fuel wood and dung. The rural household sector, which is the largest energy

consuming sector accounting for 75% of the total energy consumed by the domestic sector, depends

largely on traditional fuels. According to the 2001 census of India, only 43.5% of rural households

have an electricity connection and more than 85% of rural households use it for lighting purpose only.

90% of the rural households are dependent on biomass fuels such as fuel wood, dung and

agricultural residue for their energy demand (TEDDY 2003)

The Indian urban sector is 28.4 % of the countrys total population; it is consuming a proportionate

share of energy at 25%. Around 87% of the urban population have access to electricity to meet their

energy demands. This means that the urban sector is highly dependent on cleaner energy carriers

like electricity and LPG (liquid petroleum gas). As indicated in previous chapters about the growth in

the economy of the country, the per capita income is increasing and thus the purchasing power for a

more leisurely lifestyle with extensive usages of electricity is rising.

Another reason for growth in energy use is the shift of population from rural to urban centres. The

united nations human settlement indicators for India show a clear drift of rural population towards

urban centres. During the last two consecutive censuses (1991 -2001), it has been observed that the

urban population growth rate was 31.45, whereas the rural population growth rate was 21.2%. figure

below shows the level of urbanization for the country and expected percentages of urban population

for the year 2005(Singh and Michaelowa 2004).

This shift of population from rural to urban centres primarily for seeking better opportunities and

amenities is leading to growth in the use of clean energy and subsequently increasing energy demand

mostly through the built environment.

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Figure 2: level of Urbanization since the year 1970 -2005 Source: (Singh and Michaelowa 2004)

2.5 Electricity use in Buildings:

The emergence of a middle class society during the decades of the 1980s and the 1990s is identified

as a remarkable social development in India. This society, comprised of urban-based professionals,

administrative and business class, has been the main driving force towards modernization by their

demand of loosening of economic controls, better education for children and better standards of living.

Thus during the last decade, the residential and commercial sector has been consuming electricity at

the rate of 13.2% (Singh and Michaelowa 2004). Subsidised electricity rates and aspiration for more

comfortable style of living has been the main cause of this increase. The penetration level of

appliances is also considered one of the main reasons for this growth as indicated in the discussion

below.

Most of the electricity consumed in the residential sector is used to power appliances. The diffusion of appliances ownership is particularly elastic to income. With increasing electricity access and raising income level, the number of households owning appliances is increasing very rapidly in India. NSSO surveys (1997, 2001a, 2005b) provide appliance saturation by MPCE for rural and urban areas. The number of households owning a TV doubled from 13% in 1993 to 26% in 2002 in rural areas and increased from 49% to 66% in urban areas (NSSO, 2005b). In the case of refrigerators, the upward trend was even more impressive; saturation went from 12% in 1993 to 28% in 2001 in urban areas and from 1% to 4% in rural areas (NSSO, 1997 and 2005b). Some hierarchical level of preference among appliances can be observed. Basic appliances such as fans and TVs are more evenly distributed among households with different levels of income (Figure 4), while other appliances are owned only by households with the highest level of income. This is the case of water heaters, washing machines and air conditioners, which can be considered as more luxurious goods. In between, air coolers and refrigerators are increasing more steadily throughout the different level of income(de la Rue du Can 2009). The electricity consumption in this sector is essentially in buildings and building establishments for

various end uses. Comparing the electricity consumption figure 3 between Indian residential buildings

to commercial buildings it is clear that residential buildings use much more energy. It is also evident

from the figure below that out of the total demand for electricity the energy use by Air-conditioners is

only 7%.

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Figure 3: Annual electricity consumption or residential and commercial buildings in India Source:(Singh and Michaelowa 2004)

However, looking at the projections of rate of appliances indicated in the figure below, in the year

2005 the rate for air-conditioners was around 3% and it grew steadily to 6% and is projected to grow

to 15% by 2020. So far, the growth in air-conditioners has been based on the economic wellbeing of

the people. However, climate of regions also influences the choice of using air conditioners. In the

next chapter the different climatic zones of India have been discussed to clearly demarcate and

understand the composite climate. As it has the characteristic of all other climates.

Figure 4: Appliance penetration levels in Urban households

Source:(de la Rue du Can 2009)

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3 Climate of the region To describe the climate of Hyderabad, it is necessary to understand the climatic classification of India.

The climate of India is diverse, similar to Northern Europe. It varies from extremely hot regions, such

as Rajasthan to extremely cold regions of the Himalayas. Indias climate varies drastically from region

to region. Hence, the climate largely demands appropriate design and construction of the buildings.

Specifically the climatic factors that must be considered are solar radiation, ambient temperature,

Humidity, rainfall and wind. The National building code of India (NBC-2005) has classified the climate

of India as follows:

Figure 5: Map of India showing climatic zones (NBC 2005)

3.1 Hot and Dry

This zone lies in between the western and the central part of India as shown in Figure 3. A few towns

of this region that experience this type of climate are Jaisalmer, Jodhpur, and Sholapur. In typical hot

dry regions, the land is usually flat comprised mainly of sand and rock with sparse vegetation of

thorny trees and bushes along with cacti. The underground water level is usually very low and there

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are very few sources of water. The solar radiation levels range from 800-950w/m2 due to such high

intensities during the daytime; the surroundings of these regions get heated up very quickly. The

maximum ambient temperatures in summer are as high as 40-45DegC during the day and 20-30Deg

C at night. With the onset of winter the temperature ranges from 5-25 DegC during the day and 0-

10DegC at night. It may be noted that the diurnal variations in temperature is quiet high, that is, more

than 10 DegC.

The climate is observed to be dry due to the fact that the relative humidity is generally very low,

ranging from 20 to 40% which is further exacerbated with low vegetation and surface water bodies.

Moreover, the hot and dry regions receive less rainfall with the annual precipitation being less than

500 mm. The severity of this climate is experienced by the hot winds that blow during the day in

summers and sandstorms that appear now and then. The night is usually cool and pleasant. This

zone also experiences uncomfortable glares under clear sky conditions due to the high solar

radiation.

The night skies are clear and promote faster dissipation of heat absorbed by the ground. Hence, the

air is much cooler at night than during the day. Since the climate has high solar radiation and hot

winds blow during the day time. It is imperative to control these factors. Therefore, the design criteria

should be aimed towards minimizing heat gain by providing adequate shading, reducing exposed

area, controlling and scheduling ventilation, and increasing humidity leading to lower air temperatures.

The land surrounding the objects emits lot of heat in the afternoons and evenings. As far as possible,

this heat should be avoided by appropriate design features.

3.2 Warm and Humid

The coastal regions of the country fall under the warm humid zone. The cities that experience this

zone are Mumbai, Chennai and Kolkata. These regions have high humidity encouraging abundant

vegetation. The diffuse fraction of solar radiation is quiet high due to the cloud cover, and on clear

days the radiation can be intense. The presence of clouds promotes only marginal dissipation of heat

absorbed by the ground. Hence, this region experiences less diurnal variation in temperature. The

summer day time temperatures usually range between 30-35 Deg C and the night time temperatures

are 20 -25 DegC. Although the temperatures are not excessive, discomfort exists due to the high

humidity. An important characteristic in this region is the relative humidity, which is generally very

high, at about 70-90% throughout the year. Precipitation is also high, being about 1200 mm

per year, or even more. Hence, the provision for quick drainage of water is essential in

this zone. The wind is generally from one or two prevailing directions with speeds ranging from extremely low to very high. Wind is desirable in this climate, as it can cause sensible cooling of the

body. The main design criteria to be considered for this region are aimed towards minimising heat

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gain through shading and promote heat loss by maximising cross ventilation. Dissipation of humidity

is also essential to reduce discomfort.

3.3 Moderate

This region covers only a small portion when compared with other climatic types. Pune and

Bangalore are examples of cities that fall under the climatic zone. Areas having moderate climate are

generally located on hilly or high plateau regions like the Deccan plateau. Solar radiation is

moderately intense and is more or less the same throughout the year. Being located at relatively

higher elevations, these regions experience lower temperatures when compared to hot and dry

climates. The thermal stress induced by theses temperatures I neither too hot nor too cold. The

daytime summer temperatures range from 30 Deg C to 34 DegC and night time ranges from 17 to 24

Deg C. The relative humidity is low in winters and summers, varying from 20- 55%, and going upto

55-90% during the monsoon seasons. The total rainfall exceeds 1000 mm per year. This zone

experiences dry winters. The wind flow is strong in the summer. Their speed and direction are

influenced by the topography of this region. The sky is mostly clear with occasional presence of low,

dense clouds during summers. The design criteria are similar to the warm and humid regions.

3.4 Cold and Sunny

Cold and sunny climate covers the northern most regions of India. Places that fall in this climate are

Leh and Ladakh. The topography of this region is mountainous with little to no vegetation it is typically

considered a cold desert. Although it is very cold, the solar radiation is generally intense with very low

percentage of diffuse radiation. The average summer day time temperatures range between 17 to 24

Deg C and night time temperatures are 4 to 11 Deg C. The winters are extremely cold with the day

time temperatures ranging from -7 to 8 DegC and the night time range from -14 to 0 DegC. The cloud

cover is usually 50 % due to this the sky remains fairly clear throughout the year.

The region has very less humidity at about 10 -50% and precipitation is less than 200 mm per year.

As this region experiences cold desert climatic conditions, the design criteria are to resist heat loss by

insulation and controlling infiltration. Simultaneously, heat gain needs to be promoted by admitting

and trapping solar radiation within the living space.

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S.no Climatic Zone

Mean Monthly

Max Temp (Deg C)

Mean Monthly Relative Humidity

(%) 1 Hot-Dry Above 30 Below 55 2 Warm-Humid Above 25 Above 55 3 Temperate Between

25-30 Above 75

3 Cold Below 25 Below 75 4 Composite * Varies All values Figure 6: Classification of climate adapted from (NBC 2005)

Each climatic zone does not have the same climate for the whole year; it has a particular season for

six months and may experience the other seasons for the remaining period. A climatic zone that does

not have any season for more than six months may be called as a composite zone.(NBC 2005)

3.5 Composite climatic zone

Cities that experience composite climate have intense solar radiation in summer and a small fraction

of diffuse radiation (Nayak and Prajapati 2006). The monsoon period is predominantly diffuse

radiation due to low intensity. The maximum daytime temperature in summers is in the range of 32

43 C, and night time values are from 27 to 32 C. In winter, the values are between 10 to 25 C

during the day and 4 to 10 C at night. The relative humidity is about 20 25 % in dry periods and 55

95 % in wet periods. The presence of high humidity during monsoon months adds on the reason to

term it composite climate.

Precipitation in this zone varies between 500 1300 mm per year. This region receives strong winds

during monsoons from the south-east and dry cold winds from the north-east. In summer, the winds

are hot and dusty. The sky is overcast and dull in the monsoon, clear in winter and frequently hazy in

summer. Generally, composite regions experience higher humidity levels during monsoons than hot

and dry zones. Otherwise most of their characteristics are similar to the latter. The highest maximum

(day) temperature ever recorded was 45.5 C (113.9 F) on 2 June 1966, while the lowest minimum

(night) recorded temperature was 6.1 C (43 F) on 8 January 1946.

According to National building code(NBC 2005) of India, Hyderabad falls under the composite climate.

It is characterized by hot summers, warm humid monsoons and dry winters and none of the

conditions last longer than six months. Hot summers begin from late February, peak in May and

dissipate in June with the onset of south west monsoon. During the period of hot summers the

weather conditions are dry with high diurnal temperature - and low humidity at - .The intensity of solar

radiation is very high and the sky is rarely overshadowed. The people of the region experience a high

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degree of discomfort during such periods. This, however changes by the pre monsoon period (from

late June to October) and during this time the temperature is lower and humidity becomes high. The

sky is overcast with clouds resulting in less solar intensity due to diffuse radiation.

The period of winter commences in October and lasts till late February, during this period the region

witnesses dry and cold conditions with the temperature going as low as 5 DegC. Hyderabad has a

wide range of temperatures throughout the year, with mean daily temperatures of 30 36 C in the

summer and 20 24 C in the coldest months. Mean maximum temperatures in May are between 40

and 43 C, while peak temperatures have reached even 47 C. In the winter, mean minimum

temperatures are 13 to 17 C in December. Hyderabad has mean diurnal temperature variations of

12DegC. More than 75% of rainfall occurs during monsoon season, from June to September, with the

majority of rain coming in July. Rain increases rapidly in June (during which month 15% of annual

rainfall occurs) as opposed to May, which only receives 5% of annual rainfall.

In order to address the role of solar passive design within buildings in Hyderabad, it is important to

recognize the climatic parameters of the region. The period witnessed during the summer months as

discussed before ascribe to a hot and dry condition. In such a condition, it is imperative to control

solar radiation and movement of hot winds. The design criteria should therefore aim at resisting heat

gain by providing shading, reducing exposed area, controlling and scheduling ventilation, and

increasing thermal capacity. The presence of water bodies is desirable as they can help increase

the humidity, thereby leading to lower air temperatures. The ground and surrounding objects emit a lot

of heat in the afternoons and evenings. As far as possible, this heat should be avoided by appropriate

design feature (Nayak and Prajapati 2006).

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Figure 7: prevailing wind rose of Hyderabad

Figure 8: Climate summary and degree of heating/cooling hours

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Figure 9: Monthly diurnal averages and Daily conditions.

3.6 Climate change

One of the outcomes of the energy crisis has been the climate change. Alongside the energy issue,

climate change, which was earlier referred to as global, warming, has taken a renewed interest of

concern. Climate change is a natural phenomenon on earth and usually spans over a large segment

of time, ranging from decades to millions of years. But activities such as industrial revolution have

begun to affect the natural cycle of climate change and also added problems to the ecosystem. As a

result, the people are witnessing abnormal heating of earths surface rendering an anthropogenic

climate change.

A publication of the intergovernmental panel on Climate change indicates that global average surface

temperatures have increased by 0.76C (from0.57C to 0.95C) over the 20th century, and according

to projected models the global surface temperature will increase by 4.4 (1.4 to 5.8C) by 2100

relative to 1990. The impacts of climate change are also visible in the rise of sea level; Observations

since 1961 show that the average temperature of the global ocean has increased to depths of at least

3000 m and that the ocean has been absorbing more than 80% of the heat added to the climate

system. Such warming causes seawater to expand, contributing to sea level rise. Additional impacts

can be expected on the water cycle, carbon and nutrient cycles, air quality and the productivity of

agricultural grazing and timber lands and the geographic distribution, behaviour, abundance and

survival of plant and animal species, including vectors and hosts of human disease. (IPCC 2007)

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Figure 10: Changes in temperature sea level and northern hemisphere snow cover Source: statistics from Intergovernmental panel for climate change IPCC. Retrieved

from:http://www.ipcc.ch/publications_and_data/ar4/wg1/en/figure-spm-3.html

Observing the causes of Anthropogenic climate change, it has been found that the major contribution

comes from greenhouse gases, which are Carbon dioxide, Nitrous Oxide, Methane and other

synthetic industrial gases. Greenhouse gases cause the greenhouse effect, in which case the short

wave radiation coming from the sun is permitted and the long wave radiation coming from the earth is

trapped, moderating the earths temperature to support life. However, excessive concentration of

greenhouse gases result in the continuous rise of earths temperature.

3.6.1 Climate change in India The primary points of impact of climate change are air temperature and rainfall.

India as a peninsular country has approximately 6000km of coastline along the mainland and an

additional 1500km around its islands of Lakshadweep and Andaman and Nicobar. It is divided by the

tropic of cancer into two halves. The northern half being temperate and southern half tropical. The

peninsular region experiences more rainfall and less variation in temperatures than the inner

continent. Alternatively, the inner continent experiences temperatures from near freezing levels in

winter to 40Deg C or more during summer. The Himalayan states which are located in the

northernmost regions of the country experience sub-freezing temperatures during the winter with

elevated regions in those states receiving sustained snow.

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The primary points of impact of climate change are air temperature and rainfall. They also influence

the occurrences of extreme weather events such as the frequency and intensity of droughts, cyclones

and floods(Panagariya 2009). The following briefly discusses the changes in the temperatures and

rainfall; melting of glaciers and sea levels; and extreme weather events in India in the last century.

Temperature

Figure 11(Lal et al. 2001) shows that temperatures in India have recently increased in two phases: the

first half of the 20th century and the period since the mid-1970s. Between 1950 and 1970 there was

no trend. The warming in India is concentrated in the post-monsoon and winter seasons and in the

maximum daytime temperatures rather than night-time minimum temperatures. In the monsoon

season, temperatures exhibit a declining trend in northwest India and no trend in the rest of the

country (Panagariya 2009)

Figure 11 Temperature anomaly Source:(Lal et al. 2001)

Rainfall:

With respect to rainfall, The Government of India (India 2004), Although the monsoon rainfall at the

all- India level does not show any trend and seems mainly random in nature over a long period of

time, the presence of pockets of significant long-term changes in rainfall have been recorded. Areas

of increasing trend in the monsoon seasonal rainfall are found along the west coast, north Andhra

Pradesh and north-west India (+10 to +12 per cent of normal/100 years) and those of decreasing

trend over east Madhya Pradesh and adjoining areas, north-east India and parts of Gujarat and

Kerala (-6 to -8 per cent of normal/100 years).

Sea level:

The average of the sea level along Indias coastline is reported to be rising at 1mm per year on the

average. According to The Government of India(India 2004) at 0.4 to 2.0 mm per year, the rise is the

highest along the Gulf of Kutch in Gujarat and the coast of West Bengal. Along the Karnataka coast,

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there is a relative decrease in the sea level. Much of the rise in the sea levels has been due warming

of seawater that increases its volume.

Extreme Weather Events:

Since the last decade of the twentieth century, a significant rise in the frequency, persistency and

spatial extent of heat waves in India has been observed(IPCC 2007).

As mapped by (Akpinar-Ferrand and Singh 2010) Certain states of India were observed to be more

prone to heat waves over time as seen in figure6 . The Indian states of Bihar, Maharashtra, West

Bengal, Rajasthan, Uttar Pradesh, and Jammu and Kashmir had the highest total number of heat

waves between 1911 and 1999. Mortality rates between 1978 and 1999 have been recorded for the

northern states of Rajasthan, Bihar and Uttar Pradesh.(De et al. 2005) However, the recent severe

heat waves of 1998, 2002 and 2003, accompanied by high mortality rates, were observed primarily in

the more southern states of Orissa and Andhra Pradesh. The severe heat wave experienced in

Andhra Pradesh in 2003 resulted in a death toll of more than two-thousand. Hyderabad belongs to the

state of Andhra Pradesh, India. The state as discussed in the previous chapter of the climate also has

problems with heat waves.

Figure 12 total heat wave mortality rates (Akpinar-Ferrand and Singh 2010)

In the same research (Akpinar-Ferrand and Singh 2010) they have discussed that air-conditioners will

be important in India in the context as they are known to alleviate human health problems caused by

heat. For instance, the decrease in heat-related mortality in North Carolina, South Finland, and

Southeast England between 1971 and 1997 has been attributed to the utilization of A/Cs(Donaldson

et al. 2003).

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Figure 13 Spatial distribution of heat waves in India between 1911 and 1999 (Akpinar-Ferrand and Singh 2010).

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3.7 Growth in Air-conditioning:

In India, residential and commercial air-conditioning has become one of the fastest growing markets

Residential and commercial air-conditioning has become one of the fastest growing markets of the

cooling technology industry in India since the late 1990s, expanding 20% on average per annum as

shown in figure 8. The air-condition equipment sales have increased considerably over the decade

across all regions , especially packaged window A/C and split A/C systems which can be easily

installed by the owners(M.Santamouris 1996). It is proven that the Greenhouse gases contained in

these systems have impact on the natural environment. Recent technological and efficiency

enhancements and energy ratings have put-forth improved systems in the market. However, in

tropical countries like India there is still use of units with harmful GHGs due to their low cost(Mohanraj

et al. 2009). This will certainly have unavoidable impact on the natural environment unless it is

addressed with sensible design solutions addressed to cope with the climatic stress of the tropical

regions.

Figure 14 Increased Air-condition sales in India (Akpinar-Ferrand and Singh 2010)

In 2008, the A/C industry anticipated a large increase in sales due to growing affordability of the units,

in addition to the construction-led industry growth of 2122% (Seth.Y 2008) Following are the impacts

associated with air-conditioning are as discussed by (M.Santamouris 1996).

Environmental

Wide use of air-conditioning units can cause a shift in electrical energy consumption to the

summer season and an increased peak electricity demand.

Increased electricity energy production contributes to exploitation of the finite fossil fuels, to

atmospheric pollution and to climatological changes.

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Heat rejection during the production process (for electrical energy and air conditioning units) and

from the operation of air-conditioning units themselves increases the phenomenon of the urban

heat island.

Ozone-layer depletion can be caused by CFCs and HFCs (the most common refrigerants of

currently used air-conditioning units) from possible leakage.

Indoor air quality

Increased indices of illness symptoms known as sick building syndrome

Occupants dissatisfaction with indoor comfort conditions.

Economic

Economic and political dependence of countries with limited resources on other countries, richer

in natural resources.

3.8 Views on energy efficiency in India:

Energy use in commercial and residential buildings varies with income groups, building construction

typology climate and several other factors. Within these facets there exists a significant scope to

reduce energy use simultaneously providing the energy services for both existing and new

constructions. Although the saving potential of each may vary with typology, climate, space

conditioning needs and design based requirements, on an average it is estimated that implementation

of energy efficient options would help in achieving 30% electricity savings in new residential buildings

and 40% in commercial buildings. With existing buildings it is considered to be 20% in residential

sector and around 30 % in the commercial sector1

1 India.gov.in/allimpfrms/alldocs/15651.doc

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3.9 Concluding comment:

Residential energy use is growing in India. Apart from urbanization and level of appliance penetration,

the energy growth is also caused due to the growing use of air conditioners. Also, the energy use

differs by income and region. Energy use tends to be higher in urban regions when compared with

rural regions. Additionally, the energy intensity is higher among the economically comfortable and

decreases with declining levels of income.

Cooling energy needs is dictated not only by the climate but also the installed equipment and building

type. For any building to function appropriately, its first design response is towards the climate of its

region. Unlike office buildings, where activities are predicted and equipment loads add on to the

cooling load of the building, the activities of residential buildings are diverse. Hence climate and

building envelope features are the first important factors to be addressed for the building to have

efficient energy performance.

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4 Climate responsive design

The objectives of the research include the understanding of the building characteristics with regards

to the climate which is done by the physical observations of the case study location and building.

To evaluate the case study building it is important to discuss the effects of various factors which

influence the heat gain or loss in the buildings(Krishan et al. 2010). These factors are further divided

into Site, plan form and orientation and Building parameters. As the prevailing climate in Hyderabad is

similar to hot and dry conditions, the design objectives are referred from them. As discussed in

previously the hot and dry climate is characterised by very high radiation levels and ambient

Temperatures, accompanied by low relative humidity. Therefore, it is desirable to keep the heat out of

the building, and if possible, increase the humidity level. The design objectives accordingly are:

Resist heat gain by:

Decrea