Background to Sustainable Housing Design
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“Thermal Mass and Thermoregulation: A Study of Thermal Comfort in Temperate Climate Residential Buildings” by Samuel Parsons Bachelor of Science (Honours) Submitted in fulfulment of the requirements for the Degree of Doctor of Philosophy Centre for Environmental Studies School of Geography and Environmental Studies University of Tasmania Oct 2011 i STATEMENT OF ORIGINALITY This thesis contains no material which has been accepted for a degree or diploma by the University or any other institution, except by way of background information and duly acknowledged in the thesis, and to the best of my knowledge and belief no material previously published or written by another person except where due acknowledgement is made in the text of the thesis, nor does the thesis contain any material that infringes copyright. Samuel Parsons October 2011 i STATEMENT OF AUTHORITY This thesis may be reproduced, archived, and communicated in any material form in whole or in part by the University of Tasmania or its agents, and may be made available for loan and copying in accordance with the Copyright Act 1968. Samuel Parsons October 2011 ii STATEMENT OF ETHICAL CONDUCT The research associated with this thesis abides by the international and Australian codes on human and animal experimentation, and the rulings of the Safety, Ethics and Institutional Biosafety Committees of the University. Samuel Parsons October 2011 iii ABSTRACT The thermoregulatory influence of building materials to improve the thermal comfort of buildings has been examined primarily using climate modelling based on the work of Fanger (1972). This modelling has limitations because it does not accept that building occupants are active participants in controlling their thermal environment. This thesis addresses this knowledge gap by examining how thermal comfort in the temperate climate of Hobart, Tasmania, Australia is influenced by thermal mass in buildings. This research assessed: how the temperate climate of Hobart impacts the thermal environment of a building; how past research in passive design for energy efficiency has been adopted, and; what methods of modelling and studying thermal comfort are appropriate. The nine case studies examined a range of building and occupant types. An analysis was undertaken for each building including zoning and layout, building materials and insulation. Occupants were interviewed at the commencement of each case study which included examining acclimatisation to the local climate and thermal satisfaction with the dwelling. Seasonal temperature data were recorded in the central living space of buildings over a three month period. The research gathered dry bulb temperatures, surface temperatures, and humidity data in each building. Direct observations were made on the activities of the occupants within their thermal environment and they were surveyed regarding thermal comfort levels. Results indicate that thermal mass impacts thermal comfort levels of occupants. However, this impact can be negative or positive depending on other external factors such as the placement of thermal mass within the building, exposure of thermal mass to insolation and insulating materials around the thermal mass. In dwellings with poor thermal performance occupants can increase thermal comfort levels by more closely adapting to the thermal environment. Such techniques for adaptation include: the adjustment of clothing; the use of controls such as windows and blinds; relocation within the building; changes in posture and levels of physical activity; and acclimatisation to the local climate. The results of this research are widely applicable to Hobart‟s housing stock and could be implemented into the passive design of new buildings and retrofitting of existing buildings to improve thermal efficiency. This research shows the importance of thermal mass in passive design concepts of residential buildings. It provides details on how thermal mass should be ideally implemented in a building, including placement, orientation, and access to solar gain. ii ACKNOWLEDGEMENTS First and foremost I would like to acknowledge and thank my supervisor, Lorne K Kriwoken for the faith he has placed in me to complete this project, his time an effort invested in my work, his support of me through some exceptionally difficult personal experiences, and his fantastic sense of humor. Elaine Stratford for her words of wisdom, and the belief in me that never failed to spur me into action; Manuel Nunez for help with climatological advice and information; Mick Russell for invaluable equipment assistance; Aidan Davison for his supervision; and John Todd words of wisdom and advice. The homeowners who agreed to participate in my study. Phillipa Watson for more help, love, and advice than I can really include here. Tristan Barnes et al. for being a home away from home on so many occasions, for lyrics that inspire me, for music that I love, and for making my Sunday mornings the best they can be. The following composers who have provided the soundtrack to my writing: Jon Brion, Stan the 3rd, Carter Burwell, John Murphy, Danny Elfman, Trent Reznor, Clint Mansell, Damon Albarn, James Horner, Daniel Licht, Rolfe Kent, Michael Andrews, Javier Navarrete, Nick Cave, Warren Ellis, Angelo Badalamenti, Mark Snow, Brian Reitzell, Michael Nyman, Mike Garson, Thomas Newman, and Jonsi & Alex. Keith Bates, my partner and love. Home is not just what I write about, but what we have built together. This work is dedicated to the loving memory of my dear friend Tommy Hay. iii TABLE OF CONTENTS STATEMENT OF ORIGINALITY ................................................................................................ i STATEMENT OF AUTHORITY .................................................................................................. ii STATEMENT OF ETHICAL CONDUCT ................................................................................ iii ABSTRACT ........................................................................................................................................... ii ACKNOWLEDGEMENTS ............................................................................................................ iii Chapter 1: Introduction ....................................................................................................................... 1 1.1. Background .......................................................................................................................... 2 1.2. Significance of this Study .................................................................................................. 6 1.3. Study Scope and Aims ....................................................................................................... 6 1.4. Chapter Outline................................................................................................................... 8 Chapter 2: An Overview of Hobart, Tasmania ............................................................................ 10 2.1. Introduction ...................................................................................................................... 10 2.2. Climate of Tasmania........................................................................................................ 10 2.3. Socio-Economic Evaluation of Hobart ....................................................................... 24 2.4. Housing Stock of Hobart ............................................................................................... 25 2.5. Chapter Summary ............................................................................................................ 34 Chapter 3: Sustainable Housing Design ........................................................................................ 36 3.1. Introduction ...................................................................................................................... 36 3.2. Sustainability ..................................................................................................................... 38 3.3. Passive Design .................................................................................................................. 42 3.4. Climate ............................................................................................................................... 46 3.5. Building Site ...................................................................................................................... 47 3.6. Building Orientation and Shape .................................................................................... 47 3.7. Building Heat Flows ........................................................................................................ 55 3.8. Glazing ............................................................................................................................... 61 3.9. Building Materials and Thermal Mass .......................................................................... 66 3.10. Insulation ........................................................................................................................... 78 3.11. Passive Cooling ................................................................................................................ 88 3.12. Landscaping ...................................................................................................................... 96 3.13. Retrofitting .......................................................................................................................