STUDY ON THE IMPACT OF WINDOW SIZE AND PROPORTION ON INDOOR AIR TEMPERATURE OF BEDROOMS IN APARTMENTS by Ishrat Zerin Hossain Mou Dissertation submitted in partial fulfilment of the requirements of the Degree of MASTER OF ARCHITECTURE Department of Architecture BANGLADESH UNIVERSITY OF ENGINEERING AND TECHNOLOGY March 2017 DEDICATION To My Parents Mr. Moazzem Hossain Salim and Mrs. Ismath Ashrafi and Parents-in-Law Dr. Ehsanur Rahman and Mrs. Masuma Rahman for being my inspiration and My Husband Ar. Mashudur Rahman Fahim for giving me unconditional support and consent. iv TABLE OF CONTENTS List of Figures……………………………………………………………………………………...…..ix List of Tables………………………………………………………………………………………......xii Acknowledgement………………………………………………………………………………..…..xiii Abstract……………………………………………………………………………………...………..xiv Chapter 01: Introduction 1.1. Background………………………………………………………………………………………...1 1.1.1. General Problem......................................................................................................................1 1.1.2. Specific Problem……………………………………...……………………………………...3 1.1.3. Problem Statement………………………………………...…………………………………3 1.1.4. Objective……………………………………………………...………………………...……4 1.1.5. Significance…………………………………………………..….………………………..… 4 1.2. Research Methodology………………………………………………………..…………………....5 1.2.1. Literature Review……………………………………………….……………………...…….6 1.2.2. Data Collection…………………………………………….………………………...………6 1.2.3. Simulation................................................................................................................................7 1.2.4. Results and Analysis................................................................................................................7 1.3. Validation……………………………………………………………………..……………………8 1.3.1. Validation of the Results from Case Study Analysis………………………………….……...8 1.3.2. Validation of the Software Used…………..………………………………………....………8 1.4. Scope of the Research……………………………………………………..……………….……….9 1.5. Conclusion………………………………………………………………..……………………….10 Chapter 02: Building Energy Use, Natural Ventilation and Window Parameters 2.1. Background…………………………………………………………………………….….……...11 2.2. Energy Use in Buildings the Sector………………………………………………….…….……..12 2.3. Effects of Urbanization on Energy Demand...................................................................................12 2.4. Active and Passive Strategies for Reducing Buildings’ Energy Consumption……………..…….13 2.5. Passive Architecture………………………………………………………………………..……..14 2.5.1. Orientation………………………………………………………………………...………..15 2.5.2. Building Form……………………………………………………………...………….……15 2.5.3. Wall and Roof Insulation…………………………………………………...……...….……16 2.5.4. Window Openings for Ventilation………………………………………..…….….….……16 2.5.5. Sun Shading Device.……………………………………………………...….……………..16 2.6. Passive Cooling ………………………………………………………………….…………….…16 2.6.1. Night Flushing………………………………………………………….…………..………17 2.6.2 Natural Ventilation …………………………………………………………….……...…….18 2.6.2.1. Wind-Driven Cross-Ventilation ………………...………………………….……….18 2.6.2.2. Single-Sided Ventilation …………………………...……………………….………19 2.7. The Window and its Features for Natural Ventilation…………………………..………….……..20 2.7.1. Window-to-Wall Area Ratio ……………………………………..……….………….…….21 2.7.1.1. WWR and Energy Consumption…………………………………...………….…….22 2.7.1.2. WWR and Energy Simulation………………………...…………….……………….23 v 2.7.1.3. WWR in Naturally Ventilated Building…………………………….……………….23 2.7.2. Window-to-Floor Area Ratio.................................................................................................24 2.7.2.1. WFR for Daylighting…………………………..…………………….……….……..25 2.7.3. Air Change Rate per Hour…………………………….………………….……...………….25 2.8. Thermal Comfort………………………………………………………………..………...………26 2.8.1. Thermal Comfort in High-Rise Residential Buildings……………….…..…………..……..30 2.8.2. Thermal Comfort in Tropical Countries………………………..…………………...………31 2.9. Importance of Simulation in Building Performance………………….……………..…………….34 2.9.1. Simulation Study for Natural Ventilation…………………….…………….……………….34 2.10. Conclusion……………………………………………………………..…………..…………….35 Chapter 03: Setting the Context 3.1. Bangladesh: An Overview…………………………………………….…………..………………37 3.1.2. Climate…………………………………………………….………………………...……...38 3.2. Dhaka……………………………………………………………….…………….………………39 3.2.1. Climate of Dhaka………………………………………………….……...………………...39 3.2.1.1. Temperature…………………………………………...…….…………………..…45 3.3. Urbanization and Population Growth………………………………….……………………….…46 3.4. Energy Status of Bangladesh………………………………………….…………………….…….48 3.5. Housing Demand of Dhaka…………………………………...……….…………………….……50 3.6. Apartment Location and Size Preference of Potential Buyers……….……………………….……51 3.7. Conclusion…………………………………………………………………………………..…….53 Chapter 04: Data Collection 4.1. Research Methodology…………………………………………………………………………....55 4.2. Case Study Analysis……………………………………………………………….………….…..57 4.2.1. Selection of Case Study………………………………………………………...……..…….57 4.2.2. Data Gathering Strategies and Issues Investigated……………………..……..………….…57 4.2.3. Specifications of Typical Bedroom inside 92.903 sqm to 139.36 sqm Apartment…………58 4.3. Field Investigation……………………………………………………...…………………..……..59 4.3.1. Objective of the Field Investigation………………………...……………………...……….60 4.3.2. Sample Selection……………………………………………………...………...…………..60 4.3.3. Overview of the Field Investigated Building………………………..………..…….………61 4.3.3.1. Features of the Surveyed Room…………………………….…..………………….64 4.3.4. Instrument Used…………………………………………………….………...…………….65 4.3.5. Data Gathering Strategies……………………………………………………..….………...66 4.3.6. Issues Identified during Physical Observations and Interviews with Occupants.......…..…..66 4.4. Conclusion………………………………………………………………………………..……….67 Chapter 05: Simulation Study 5.1. Methodology of Simulation……………….…………………………………………..…………..68 5.2. Objective of the Simulation Study……………………….……………………….……………….69 vi 5.3. Simulation Tool………………………………………………………………..………………….69 5.4. Thermal Simulation Strategy…………………………………………………..………………….70 5.4.1. Inputs used during Thermal Simulation……………………..……………………….….….71 5.4.2. Constant Variables ……………………………………………..………………….……….75 5.5. Calculations used in Thermal Simulation…………………….………………………….………..76 5.5.1. Assumptions for WWR and WFR Calculations….…………………..…….……………….76 5.6. Thermal Data Analysis Steps………………………………………………………………..…….76 5.7. CFD Simulation Strategies……………………………….……………………………………….77 5.7.1. Specifications used in CFD Analysis ……………………………..………………………..77 5.7.2. CFD Data Analysis Steps……………………………….……………..……………………78 5.8. Conclusion………………………………………………………………………..……………….79 Chapter 06: Data Analysis and Evaluation 6.1. Effect of Orientation (North-East, North-West, South-East and South-West)….……...…………81 6.1.1. Night Ventilation at 5 ACH in Cross-Ventilated State for WWR….………………………82 6.1.2. Day Ventilation at 50 ACH in Cross-Ventilated State for WWR…………..……..………..83 6.1.3. Average Temperature for April…………………………………………….……...………..84 6.2. Effect of Varied Ventilation (Day and Night Ventilation) ……………………………...……..….85 6.2.1. WWR at 50 ACH ……………………………………………………………....…………..85 6.2.2. WFR at 50 ACH ……………………………………………………………....……………86 6.3. Effect of Air Change Rate (50 ACH and 100 ACH) for Night Ventilation………...………………88 6.3.1.1. WWR for 24 hour…………………………………………………………………………88 6.3.1.2. WFR for 24 hour……………………...…………………………………………………..89 6.3.2.1. WWR for Occupancy Hour…………….…………………….…………….……………..90 6.3.2.2. WFR for Occupancy Hour……………………..….…...………………………………….91 6.3.3. Average Temperature Range for April…………………...…………………………………92 6.4. Effect of varying WWR and WFR on Cross-Ventilated, and Single-Sided South and West Ventilated State …………………………………………….……………………93 6.4.1. Night Ventilation varying WWR for 24 Hour at 100 ACH…………...……………………..93 6.4.2. Average Temperature of April for WWR…………………………………………...………94 6.4.3. Night Ventilation varying WFR for 24 Hour at 100 ACH………………………..…………95 6.4.4. Average Temperature of April for WFR…………………………………………..………..96 6.5. Effect of varying WWR in Cross-Ventilated State……………………………………...…………97 6.5.1. DTS Analysis ……………………………………………..………………..………………97 6.5.1.1. DTS Analysis for 24 hour………………………………….……………..………..97 6.5.1.2. DTS Analysis for Occupancy Hour…………………………...……………………99 6.5.2 CFD Analysis ……………………………………………………...………………………100 6.5.2.1. Air Flow Rate…………………………………………..…………………………101 6.5.2.2. Air Flow Vector…………………………………………..…….…………………101 6.6. Trend of Comfort Percentage in Cross-Ventilated State during Summer and Winter….………..106 6.6.1. Cross-Ventilation during Day Ventilation at 50 AC for 24 Hour Period…………….107 6.7. Conclusion……………………………………………………………….………………………108 vii Chapter 07: Conclusion and Recommendations 7.1. Introduction…………………………………………………………………………………..….109 7.2. Findings of the Research…………………………………………………………………………109 7.2.1. Apartment Size Preference, Typical Bedroom Size and Window Location and Size….….109 7.2.2. Effect of WWR and WFR on Indoor Air Temperature for different Orientations……..….109 7.2.3. Effect of WWR and WFR on Indoor Air Temperature Day and Night Ventilation….……110 7.2.4. Effect of WWR and WFR on Indoor Air Temperature for Varied ACH…………………..110 7.2.5. Effect of WWR and WFR on Indoor Air Temperature in Cross-Ventilation and Single-Sided Ventilation on South and West Wall………………………...………….111 7.2.6. Influence of Window Size on Indoor Air Temperature during Summer and Winter…….…112 7.2.7. Influence of WWR on Indoor Air Temperature in Cross-Ventilation ……………….…...112 7.3. Recommendations……………………………………………………………………………….112 7.4. Suggestion for