Study on thermal adaptation in naturally ventilated office buildings in Japan

Abstract

This paper discusses the relationship between thermal environment and adaptive thermal comfort in Japanese office buildings of Japan where occupants are able to open the windows. With the use of adaptive thermal control opportunities in offices, it is possible to reduce the heating and cooling energy consumption. There are very limited studies on buildings that are ventilated naturally with open windows versus numerous studies on air-conditioned buildings for constructing an adaptive model based on Japanese lifestyle and climate. In this context, this research focused on thermal comfort and adaptive opportunities in a naturally ventilated office building. In this study we conducted a questionnaire based field survey in autumn and winter seasons of year 2015 in the administration building of the University of Tokyo. Simultaneously we also carried out environmental measurements and recorded thermal comfort responses from occupants. Analyzing the data we found that the measured value of comfort temperature can be closely predicted using nonlinear regression analysis. Also the adaptive model which can be used over a wide range of outdoor air temperatures is proposed. It is found that the change of comfort temperature becomes less as the outdoor air temperatures becomes higher than 30°C and lower than 20°C.