Understanding patterns of adaptive comfort behavior in university graduate research offices–––A case study of a university in Beijing

Energy conservation and emission reduction in campus building are key issues as the area of campus buildings and per capita energy consumption rise. Hence, from 2021 to 2022, this study conducted a year-long field survey at a university in Beijing, China, focusing on seven graduate research offices with varying occupancy rates. The indoor thermal environment and air conditioning (AC) usage patterns in graduate research offices were statistically analyzed. And an adaptive thermal comfort model applicable to graduate research offices in Beijing area was established. The results show that students typically adjust to the environment by modifying their clothing and utilizing AC, with the act of opening windows being infrequent. There is excessive use of AC by students. 90 % of ACs are turned on for supplemental heating at 17.6 °C and supplemental cooling at 28.0 °C. And 90 % of air conditioners are turned off when the indoor air temperature rises to 26.0 °C during heating period or drops to 25.7 °C during cooling period. However, the neutral temperature is 21.9 °C in heating period and 26.8 °C in cooling period, the thermal preferred temperature is 24.0 °C in heating period and 25.4 °C in cooling period. More than 80 % of subjects voted comfortable when the temperature ranges between 18.2 ∼ 26.7 °C in heating period and 25.2 ∼ 28.0 °C in cooling period. This study serves as a crucial reference point for future research on heating, ventilation and air conditioning in graduate student offices and for promoting energy conservation and emission reduction across university campuses.