Application of hierarchical cluster analysis in age segmentation for thermal comfort differentiation of elderly people in summer

Abstract

Thermophysiological functions should be considered in the age segmentation of elderly people for thermal comfort differentiation. This paper aims to establish a scientific age segmentation criterion for elderly people based on thermal physiological demands. Firstly, field measurements and questionnaires are conducted in two pensioners’ buildings, and hierarchical cluster analysis is adopted to segment the age of elderly people based on thermophysiological functions in summer. Secondly, the effects of the basal metabolic rate (BMR), body fat percentage (BF%) and cardiac output (CO) on the physiological indexes are analyzed, then the thermal sensation deviation degree and the environmental sensitivity of the elderly people at different ages are analyzed. Finally, subjective perception and physiological parameter are combined to explore summer indoor environmental comfort zones for elderly people at different ages. The results show that the age of elderly people is segmented into [60, 69], [70, 89] and [90, 99]. With the increase of age, BMR and CO decrease, and BF% increases; the sensitivity of subjective perception to temperature, relative humidity and air speed decreases, and the sensitivity of MST to temperature and relative humidity also decreases. For the three age groups, the air temperature comfort zones are 23.25–27.41°C, 19.50–28.67°C and 20.72–30.73°C, respectively; the humidity comfort zones are 42.50–60.83%, 40.50–68.00% and 35.00–71.67%, respectively; and the air speed comfort zones are 0.02–0.31 m/s, 0–0.27 m/s and 0–0.29 m/s, respectively. This study can provide theoretical support for thermophysiological age segmentation criteria and differentiated environment design for elderly people in summer.