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Occupants' adaptive responses in non-air-conditioned workplaces

  • Liu, Jing
Publication Date
Jan 01, 2012
OpenGrey Repository


The achieved thermal comfort of occupants could be regarded as a result of not only physical environmental conditions but also three categories of adaptations (e.g. physiological, behavioural and psychological dimension). In this research, the thermal conditions in workplaces in the UK and China were investigated and were further linked to thermal responses of occupants. The adaptations of subjects were also studied individually and comprehensively with the aim to better understand the mechanism of adaptations and to establish those adaptations and corresponding alternatives that interrelate to affect thermal comfort. The thermal comfort and adaptive responses survey covered a year-long period from April, 2010 to April, 2011. A total of 41 and 148 respondents participated in the field investigations in the UK and China and provided 1022 and 1178 datasets, respectively. The results of the field study indicated that subjects in China case were more tolerance of the variations of ambient thermal conditions and subsequently produced more pleasant thermal sensations and lower thermal dissatisfaction rate. The skin physiological responses (e.g. mean skin temperature and GSR) of human body in real workplace environment were found to be time-dependent. At on arrival stage, which was equivalent to settling-down stage in climatic chamber experiments, mean skin temperatures demonstrated almost vertical increase regardless of subjects' clothing levels and activity levels. The different combinations of clothing and physical activity levels had direct impact on skin physiological responses of occupants under various thermal conditions. The studied physiological variables in this research demonstrated few tendencies at departure stage. The results of analysis of adaptive behaviour data illustrated that occupants were active players in environmental control and their adaptive responses were driven strongly by thermal stimuli and varied from season to season and from time to time even on the same day. Those adaptive responses of occupants were thermally, socially, economically and habitually conditioned. The developed adaptive behavioural predictive model using three statistical methods provide comprehensive understanding of windows operation behaviour in real environment. Psychological adaptation analysis indicated that psychological issues such as perceived environmental control level and thermal expectation had positive impact on thermal sensations of occupants. The findings of comprehensive effects of adaptations study revealed the footprint of the adaptations of the subject in their real thermal environment. The results of analysis of data using Analytical Hierarchy Process (AHP) method showed that physiological adaptation was the most important factor impacting achieved thermal comfort of occupants in two studies. Although the rankings of the latter two factors for the UK and China cases were reversed, the discrepancies were not significant. Highlights of originality • The skin physiological responses of human bodies with the considerations of different combinations of clothing activity levels are studied in real workplace environment by using wearable armband, which provides reliable data with comfortable wearing experience; • The skin physiological responses are identified as time-dependent. The sensitivities of mean skin temperature and GSR to the changes in magnitude of clothing and activity levels under various thermal conditions are identified by performing multiple comparisons. The corresponding discrepancies among combinations basically reach statistically significant level (P<O.05); • The dynamic processes of adaptive behavioural responses of occupants are demonstrated in graphic form as a function of both indoor and outdoor temperatures, the seasonal variations and the operation temperature ranges of different adaptive approaches are identified; • The effects of three categories of adaptations are studied and verified individually and comprehensively by means of employing various statistic methods, such as multiple comparison analysis, logistic regression, the Markov process, survival analysis, two-tailed Hest, cross-tabulation and AHP, etc., which bridge the gap between heat balance theory and adaptive thermal comfort study. These three categories of adaptations interact with each other and play positive role enabling occupants to achieve thermal comfort in real workplace environment; • The Analytic Hierarchy Process (AHP) is first time used to quantify the weights of three categories of adaptations. Physiological adaptation is found to be the most important factor influencing achieved thermal comfort of occupants. The rankings of other two categories of adaptations are slightly reversed in the UK and China cases. The contributions of corresponding six elements, /such as physiological parameters/ status, indoor environment, outdoor environment, personal physical factors, environmental controls and thermal expectation, are also quantified. It provides opportunity to better understand the adaptive mechanisms in quantitative way; • The influences of non-physical factors on adaptive responses and thermal comfort are revealed by means of performing comparative analysis. They are socially, economically and habitually conditioned. / EThOS - Electronic Theses Online Service / GB / United Kingdom

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