GREEN ROOF DESIGN AND PRACTICES: A CASE OF DELHI A thesis submitted to the College of Architecture and Environmental Design of Kent State University in partial fulfillment of the requirements for the degree of Masters of Architecture By Rohini Srivastava August 2011 Thesis written by Rohini Srivastava B.Arch., Guru Gobind Singh Indraprastha University, 2007 M.Arch., Kent State University, 2011 Approved by -------------------------------------, Advisor Adil Sharag Eldin -------------------------------------, Interim Associate Dean Jonathan Fleming -------------------------------------, Dean, College of Architecture and Environmental Design Douglas Steidl TABLE OF CONTENTS TABLE OF CONTENTS………………………………………………………………...iii LIST OF FIGURES………………………………………………………………………vi LIST OF TABLES………………………………………………………………………..ix ACKNOWLEDGEMENTS……………………………………………………………….x CHAPTER 1. GREY TO GREEN: A STRATEGY FOR DELHI ............................................... 1 1.1 Prelude .......................................................................................................... 1 1.1.1 Indian Architecture .............................................................................. 2 1.1.2 Green roofs – a sustainable Practice for Delhi .................................... 6 1.1.3 Office buildings ................................................................................... 7 1.2 Problem Statement ....................................................................................... 9 1.3 Objectives ................................................................................................... 10 1.4 Method ........................................................................................................ 10 1.5 Scope .......................................................................................................... 11 2. AN INTRODUCTION TO GREEN ROOFS ...................................................... 14 2.1 Introduction ................................................................................................ 14 2.2 Background ................................................................................................ 14 2.2.1 History of Roof Gardens ................................................................... 15 2.2.2 The Development of Green Roofs ..................................................... 17 2.2.3 Contemporary use .............................................................................. 18 2.3 Green Roof Systems ................................................................................... 20 2.4 Green roof system components .................................................................. 23 2.4.1 Structural Layer ................................................................................. 23 2.4.2 Growing Media .................................................................................. 27 2.4.3 Vegetative Layer ............................................................................... 27 2.5 Benefit of a green roof installation ............................................................. 28 2.5.1 Storm water runoff management ....................................................... 29 2.5.2 Mitigation of Urban Heat Island ....................................................... 30 2.5.3 Habitat restoration and wildlife preservation .................................... 31 2.5.4 Roof life longevity ............................................................................. 32 2.5.5 Aesthetic pleasure .............................................................................. 34 iii 2.5.6 Food production ................................................................................ 35 2.5.7 Acoustic benefits ............................................................................... 36 2.5.8 Healthy work environment and Amenity value ................................ 36 2.6 Conclusion .................................................................................................. 37 3. THERMAL BENEFIT OF GREEN ROOFS- A CASE FOR DELHI ................ 39 3.1 Thermal benefits of green roof ................................................................... 39 3.2 Green Roofs for New Delhi ........................................................................ 39 3.2.1 Climate of Delhi ................................................................................ 40 3.2.2 Best practices ..................................................................................... 42 3.3 A review of green roof studies ................................................................... 44 3.3.1 Mass Effect cooling ........................................................................... 44 3.3.2 Reduction of heat flux ....................................................................... 45 3.3.3 Evaporative cooling effect ................................................................. 46 3.4 Green roof study for Delhi ......................................................................... 47 3.5 Need for further studies .............................................................................. 49 4. DETERMINING THE PARAMETERS.............................................................. 51 4.1 Aim of the Study ........................................................................................ 51 4.2 Preliminary study: heat gain through building envelope ........................... 51 4.2.1 Building Roof .................................................................................... 52 4.2.2 Openings………….. .......................................................................... 54 4.2.3 Findings……………. ........................................................................ 56 4.3 Green roof study for Delhi ......................................................................... 56 4.3.1 Green roof model description ............................................................ 57 4.3.2 Computational model ........................................................................ 58 4.3.3 Green roof simulation ........................................................................ 59 4.4 Discussion .................................................................................................. 70 5. ARCHITECTURAL APPLICATIONS .............................................................. 72 5.1 Green Roof design process ......................................................................... 72 5.2 Potential for green roofs in office buildings ............................................... 73 5.3 Green roof retrofit ...................................................................................... 74 5.3.1 Building Selection for the retrofit ..................................................... 75 5.3.2 Building description .......................................................................... 75 iv 5.3.3 Green roof modeling ......................................................................... 78 5.3.4 Conclusion……. ................................................................................ 82 5.4 A case for new buildings ............................................................................ 84 5.4.1 Reduction in solar exposure .............................................................. 86 5.4.2 Lower level of solar gain ................................................................... 89 5.4.3 Resistance to heat transfer through the envelope .............................. 91 5.4.4 Increase heat loss through envelope using green roofs ..................... 92 5.5 Building Views ........................................................................................... 93 5.6 Cooling load benefit ................................................................................... 94 5.7 Conclusion .................................................................................................. 96 6. CONLUSIONS .................................................................................................... 97 6.1 Comparison of benefits with conventional roofs ....................................... 97 6.2 Summary of findings .................................................................................. 99 6.2.1 Building design .................................................................................. 99 6.2.2 Green roof components ................................................................... 100 6.3 Impact of the study ................................................................................... 101 6.4 Limitations ................................................................................................ 102 6.5 Future work .............................................................................................. 103 APPENDIX A. List of Vegetation………………………………………………………...104 REFERENCES………………………………………………………………………....107 v LIST OF FIGURES Figure Page 1.1 The Jagadambi Temple, Khajuraho……………………………………….. 2 1.2 Lingaraj Temple, Bhubaneswar…………………………………………… 2 1.3 Man Mandir, Rajput palace Gwalior………………………………………. 3 1.4 Diwan-i-Khas, Delhi………………………………………………………. 3 1.5 The Victoria Memorial Hall……………………………………………….. 3 1.6 A bungalow, New Delhi…………………………………………………… 4 1.7 A Bungalow, Ahmedabad…………………………………………………. 4 1.8 Chandigarh Capitol Complex……………………………………………… 4 1.9 Gandhi Labor Institute…………………………………………………….. 5 1.10 The India International Centre, New Delhi………………………………... 5 1.11 The Connaught Place area, New Delhi……………………………………. 5 1.12 Gateway Tower, Gurgaon………………………………………………….