Investigation of Thermal Comfort and Improvement Strategies for Multi-Functional Transitional Spaces in Public Buildings
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Investigation of Thermal Comfort and Improvement Strategies for Multi-functional Transitional Spaces in Public Buildings By Ming Yeung (Jason) Tse A thesis submitted for the degree of Doctor of Philosophy Welsh School of Architecture Cardiff University Oct 2020 Investigation of Thermal Comfort and Improvement Strategies i for Multi-functional Transitional Spaces in Public Buildings ABSTRACT Transitional spaces have been widely applied in building designs nowadays, which are present in the form of atria, lobbies, corridors and covered streets. As they have become common features of buildings, they may account for 10 to 40% of the total volume in different types of buildings. However, thermal discomfort has been revealed in such spaces of several newly constructed buildings, where there are still no recommended acceptable comfort range and thermal comfort prediction methods for transitional spaces. This research aims to investigate environmental performance and adaptive comfort of transitional spaces in order to achieve acceptable thermal comfort level by identifying the thermal comfort ranges, people’s adaptive behaviours and means to improve thermal comfort. Three public buildings in Cardiff were selected as case studies for the research. They were the National Assembly for Wales Senedd, the Hadyn Ellis Building and the Royal Welsh College of Music and Drama. The whole research consists of two major work stages – the field studies and computational analysis. The field studies included on-site questionnaire surveys and physical measurements; and the computational analysis was conducted by coupling software techniques of CFD modelling and HTB2. The field studies were carried out in summer and winter period where the total responses from the questionnaire surveys were 736 and 580 for these buildings respectively. It is M. Y. TSE, JASON ABSTRACT Investigation of Thermal Comfort and Improvement Strategies ii for Multi-functional Transitional Spaces in Public Buildings concluded from the research that people have adaptability to their thermal environment., based on the strong correlations between the clothing value and indoor operative temperature, and that the majority of people (nearly 80%) opted for self-adaptive actions to overcome uncomfortable situation. With the large thermal comfort dead bands identified, the research work also concluded that a fine control of the indoor temperature to maintain an acceptable comfort level within building transitional spaces is not necessary. Correlation analysis also suggested that PMV model is not accurate in thermal environmental prediction in building transitional spaces. The computational analysis further evaluated the impacts of different system setups on the thermal comfort within the transitional spaces of the selected surveyed buildings under extended climatic scenarios. The study confirms that passive design such as natural ventilation is helpful in improving the thermal environment but under extreme weather conditions, active system shall be operated at the same time. By just operating the underfloor radiant system is good enough to maintain an acceptable thermal comfort within the building transitional spaces during warm season. However, in order to have effective control of thermal environment withing building transitional spaces, both the underfloor radiant system and underfloor air distribution system shall be designed and operated. The findings of this research could help the decision-makers and architects to improve thermal performance of both existing and future designs of indoor transitional spaces. M. Y. TSE, JASON ABSTRACT Investigation of Thermal Comfort and Improvement Strategies iii for Multi-functional Transitional Spaces in Public Buildings ACKNOWLEDGEMENTS It is definitely not an easy process to get this thesis submitted. From the very beginning of the PhD where I did not have a solid idea of how to construct the analytic framework and how far I was from the end of “tunnel”. Especially when I conducted the PhD as a part-time student while having a full-time work as an engineering consultant, it made the hard process even harder. Without the supports from my friends, parents, tutors and supervisors, I would not have made this happen. Lord Jesus Christ, who has given me wisdom, opportunities of meeting all of my PhD supporters and power to help me through all the difficult times, is the very first one I would like to thank to. I would also like to take this chance to express my gratitude to all of my supporters so far. The very first one should go to Professor Daniel Chan, who patiently provided guidance since I first graduated from my undergraduate and encouraged me to take the PhD study. He also hooked me up with my PhD supervisor Professor Phil Jones, whom I would like to send my biggest thanks and appreciation. His continued intellectual challenges and excellent supervision have made me grow and successfully got through the “tunnel”. My gratitude shall be extended to Dr. Jimmy Tong, who used to be my line manager at Arup. His constant supports, guidance and knowledge and experience sharing have boosted my growth in my career development and PhD study. Particularly I would like to thank to his M. Y. TSE, JASON ACKNOWLEDGEMENT Investigation of Thermal Comfort and Improvement Strategies iv for Multi-functional Transitional Spaces in Public Buildings support on my application of intra-company transfer which offered me an invaluable opportunity to work and study aboard in Cardiff for two years. I am also deeply grateful for my parents’ and family’s unlimited encouragement, support and care. My special appreciation shall go to my wife Sherine, and my beloved daughter Ashleigh for being my motivation. Last but not least, my deepest gratitude is dedicated to the souls of my grandparents, who raised me for more than 20 years. M. Y. TSE, JASON ACKNOWLEDGEMENT Investigation of Thermal Comfort and Improvement Strategies v for Multi-functional Transitional Spaces in Public Buildings TABLE OF CONTENTS ABSTRACT ........................................................................................................................................ i ACKNOWLEDGEMENTS .............................................................................................................. iii Chapter 1. INTRODUCTION ........................................................................................................ 9 1.1 Background ..................................................................................................................... 10 1.1.1 Background of Transitional Spaces ............................................................................ 10 1.1.2 Significance of Development of Transitional Spaces................................................. 12 1.2 Thermal Comfort Issues of Existing Transitional Spaces .......................................... 16 1.3 Research Questions ........................................................................................................ 19 1.4 Hypothesis ....................................................................................................................... 20 1.5 Aim, Objectives and Scope ............................................................................................ 20 1.5.1 Research Aim ............................................................................................................. 20 1.5.2 Research Objectives and Scope .................................................................................. 21 Chapter 2. LITERATURE REVIEW ........................................................................................... 23 2.1 Introduction .................................................................................................................... 24 2.2 Evolution of Transitional Spaces .................................................................................. 26 2.3 Architectural Forms of Transitional Spaces ................................................................ 38 2.4 Relationships among Architectural Form, Thermal Comfort and Energy Performance of Transitional Spaces ......................................................................................... 41 2.4.1 Impacts of Architectural Form on Thermal Comfort in Transitional Spaces ............. 41 2.5 Evaluation of Thermal Comfort in Transitional Spaces ............................................ 49 2.5.1 Overview of Thermal Comfort in Built Environments .............................................. 49 2.5.2 Knowledge Gap of Thermal Comfort in Transitional Spaces .................................... 51 2.6 Thermal Comfort in Outdoor Spaces ........................................................................... 55 2.6.1 Comfort Standards for Outdoor Spaces ...................................................................... 57 2.6.2 Review of Comfort Prediction Models for Outdoor Spaces ....................................... 58 2.7 Thermal Comfort in Indoor Spaces .............................................................................. 61 2.7.1 Comfort Standards for Indoor Spaces ........................................................................ 62 M. Y. TSE, JASON TABLE OF CONTENTS Investigation of Thermal Comfort and Improvement Strategies vi for Multi-functional Transitional Spaces in Public Buildings 2.7.2 Review of Comfort Prediction Models for Indoor Spaces ......................................... 69 2.7.3 Review of People’s Adaptive Behaviours in Indoor Built