ABSTRACT Energy consumption in the buildings sector is very high and is expected to increase further due to increase in standards of living and change in typology of the building. Other major factor which has a significant effect on energy consumption is climate, especially in hot and dry climate. There is vast temperature fluctuation in such type of climate which promotes the use of air conditioning system, thus increasing the energy consumption. The Study investigates the performance of the Passive Downdraft Evaporative Cooling (PDEC) technique for energy conservation for commercial building sector in the hot and dry region of Ahmedabad. The Study examines four different scenarios, 1) Conventional Case, 2) Design Envelope case 3) ECBC Envelope Design case and 4) ECBC Envelope Design case with Evaporative Cooler (EC). Energy consumption of these fours scenarios will be compared with actual building observation. Performance in terms of Energy consumption in all scenarios is measured through simulation software 'eQuest'. Existing building with similar building orientation is simulated with constant and variable parameters considered in each scenario. Assumption like no of occupants, floor area of the building, working hours and Wall Window Ratio (WWR) % of the building are considered constant in each scenario. Final results are compared with actual building observations and comparative analysis is done in terms of Cooling load, Energy consumption, Co2 emissions and other co-benefits. The Research finding proves that Passive Down draught cooling technique offers real opportunity for improving the ambient thermal comfort conditions in building whilst reducing the cooling load of air-conditioning systems, thereby reducing energy consumption. It has potential to significantly reduce the indoor air temperature. It can provide indoor thermal comfort without significant energy use and can also produce a better indoor environment by providing 100% fresh, cool air into a space. The analysis confirms the advantage of the application of these passive cooling strategies in hot dry climate.The results can be used to estimate the potential of energy savings in commercial buildings in Ahmedabad and also in developing recommendations to encourage the use of such passive cooling techniques. As commercial building floor area in Ahmedabad is projected to double by 2035 (Low carbon Society Vision 2035: Ahmedabad, Oct 2009), there is a large potential to conserve the energy. Developing guidelines and action plan to promote such techniques will certainly help to reduce energy consumption, hence reducing GHG emissions. CONTENTS Abstract ii Acknowledgement iii CONTENTS iv List of Figures vii List of Tables ix 1 Introduction 1.1 Introduction 2 1.1.1 Climate Change and Buildings 3 1.2 Scenario in India 4 1.2.1 Building Construction Growth in India 4 1.2.2 Energy Consumption Scenario in India 4 1.2.3 Need of the study 7 1.3 Research study 8 1.3.1 Aim 8 1.3.2 Objectives 8 1.3.3 Research questions 8 1.3.4 Scope and limitations 8 1.3.5 Methodology 9 2 Ahmedabad : Energy and Buildings 2.1 About Ahmedabad 12 2.1.1 Growth of the City 12 2.1.2 Climate 12 2.1.3 Weather Data analysis 13 2.1.4 Electricity Consumption 14 2.3 Summary 14 3 Passive and Hybrid Cooling Techniques : Case studies 3.1 Passive cooling tehcniques and its origins 18 3.2 Earth Air Tunnel 19 3.2.1 Case Study 1 19 3.3 Wind towers 20 3.4 Evaporative cooling 21 3.4.1 Case study 2 21 3.5 Passive Downdraught Evaporative Cooling 23 3.5.1 Case Study 3 24 3.6 Passive Design Strategies 25 3.6.1 Internal Heat Gain 26 3.6.2 External Heat gain 26 3.6.2.1 Building orientation 26 3.6.2.2 Site Location and Landscape 27 3.6.2.3 Building shape 27 3.6.2.4 Building envelope 27 3.7 Summary 30 4 Scenario development and Simulation 4.1 Base case selection 32 4.2 Scenario Development 35 4.2.1 Conventional Case 36 4.2.2 Envelope Design Case 36 4.2.3 ECBC envelope Design Case 37 4.2.4 ECBC Envelope Design + EC Case 38 4.3 Simulation Methodology 38 4.3.1 Simulation Tool 38 4.3.1.1 Analysis Methods 40 4.4 Summary 42 5 Findings and Conclusion 5.1 Comparative Analysis 44 5.1.1 Analysis part 1 44 5.1.2 Analysis Part 2 45 5.2 Co-Benefits 47 5.2.1 Cost Efficiency 47 5.2.2 Energy Savings 47 5.2.3 Co2 Emission Reduction 48 5.2.4 Health and Productivity 50 5.3 Summary of Findings 51 5.4 Future Potential 51 5.4.1 Barriers 53 5.5 Conclusion 54 Glossary 58 7.1 Bibliography 68 7.2 Refernces for Figures 72