Comfortable clothing model of occupants and thermal adaption to cold climates in China

Adjusting clothing for changing climates is an effective way for the perseverance of human thermal comforts. In this study, the clothing insulation (I-clo) of occupants and their thermal adaption to cold climates are discussed based on the Chinese Thermal Comfort Database. Particularly, the raw data was selected from five climate zones of China: severe cold (SC), cold, hot summer and cold winter (HSCW), hot summer and warm winter (HSWW) and Temperate regions. Statistical approaches were adopted to understand how indoor and outdoor air temperatures, types of climate zones and buildings play roles in the clothing behaviour of occupants. Finally, a linear mixed model of I-clo was proposed by inputting the most influential numerical variable and categorical variables, i.e., indoor air temperature (t(a)), tags of climate zones and building types. The result indicated that ta in the northern parts of China where district heating is employed were perceivably higher, compared to that in HSCW and Temperate areas with separate heating systems indoors. Besides, the clothing behaviour correlated greater with indoor air temperature than outdoor air temperature, as the database incorporated environmental parameters in civil buildings where people stayed indoors most of time. The I-clo when individuals were in thermal comfort significantly differed from that when they were uncomfortable. So, comfortable clothing insulation was further analysed to establish the model of I-clo. The model gives an explanation of how individuals' clothing behaviour interact with t(a) in different building contexts, thus providing a support for indoor environmental design.