Study on the outdoor thermal comfort evaluation of the elderly in the Tibetan plateau

Abstract

China's aging population is an increasingly serious concern. Adding outdoor space can increase the frequency of outdoor activities of the elderly and effectively improve their quality of life. In this study, Lhasa was used as an example. We examined the thermal comfort of a typical outdoor activity space for the elderly during winter and summer. Microclimate measurements and a questionnaire survey were administered to the participants on typical days during winter and summer, and the outdoor thermal environment sensitivity, sex differences in thermal sensation, thermal neutral physiological equivalent temperature (PET), and comfort range of the elderly in the Tibetan Plateau were calculated and analyzed. A regression model was established between the sensitive thermal environmental indicators and the subjective thermal perception to explore the influence of thermal environmental indicators on the expectations of the elderly. The following results were obtained. 1. The elderly in Lhasa were more sensitive to changes in the thermal environment during winter than during summer. During winter, the wind was the most sensitive factor, while sunshine was the most sensitive factor during summer, and the sensitivity of women was higher than that of men. The mean radiation temperature (Tmrt) and wind speed (Va) were the climate parameters most sensitive to changes in the thermal environment. 2. The annual outdoor neutral PET of the elderly in Lhasa was 20.6 °C. The outdoor neutral PET in winter was 12.76 °C/11.08 °C, and the outdoor neutral PET in summer was 25 °C/22.14 °C. Moreover, there were differences between the thermal comfort of neutral PET of the elderly in other climatic regions and those in Lhasa, especially between the lower limits. 3. During winter, the elderly preferred a higher average radiation temperature to meet the needs of thermal comfort, while during winter and summer, the elderly preferred a lower wind speed.