Empirical determination of the width of the comfort band in an adaptive model for Japanese office buildings

• The comfort band for adaptive model is derived from Probit analysis. • The comfort band was ±2.0°C at 90% and ±2.5°C at 80% for Japanese offices. • The comfort band obtained are lower than the ASHRAE standard. • More than 80% of comfort temperature are within the comfort band. Thermal comfort has been discussed as a subject before 1930. The pattern of global warming and issues regarding energy use has caused a rise in the interest in this subject. This study empirically derives a comfort band for an adaptive model in Japanese office buildings as the global standards do not include databases from Japan and so might not be applicable in that context. Field data were collected in 17 mixed-mode (MM) and 6 Heating, Ventilation, and Air Conditioning (HVAC) office buildings located in Kanto region of Japan. Two thermal comfort field studies were conducted for two years which collected 7,295 comfort votes, each with a suite of accompanying environmental parameters, including air temperature, and globe temperature. The comfort band obtained by probit method was ±2.0°C at 90% and ±2.5°C at 80% for free running (FR) mode as well as heated (HT) & cooled (CL) modes for Japanese office buildings using the probit method. The proposed adaptive models can be used to determine indoor comfort temperature from the outdoor air temperature. Further, this paper elaborates an analytical approach for the empirical determination of the comfort band for application in future field studies in thermal comfort.