Adaptive thermal comfort of the elderly in Xi’an

To derive deeper insight into thermal comfort and demands of the elderly in different climate conditions in Xi’an, the authors survey healthy elderly people over 60 years old and adopt field study methods of subjective questionnaire of thermal comfort and objective physical environment tests. The research is carried out in winter, transitional season and summer, and obtains 843 valid questionnaires, including the main information on human thermal sensation, thermal acceptability, and indoor and outdoor thermal environment parameters. Through statistical analysis methods, the authors find that the clothing regulation and thermal sensation in the transitional season are the most sensitive with temperature changes. The neutral temperatures in winter, transitional season and summer are 19.4 ℃, 22.6 ℃ and 23.1 ℃, respectively, and 20.3 ℃ for the whole year. 80% and 90% acceptable temperature ranges are 13.8 to 30.5 ℃ and 17.2 to 27.0 ℃. The established adaptive thermal comfort model for the elderly in Xi’an is significantly different with that in ASHRAE 55 and the youth’s model in Xi’an, which shows the higher the temperature, the greater the difference between them. The result is determined by the particularity of psychological, physiological and behavioral adaptation of the elderly. The findings can provide a reference for establishing the design standard of indoor thermal environment for residential buildings of the elderly in cold zone of China.