Comparative analysis of indoor thermal environment characteristics and occupants’ adaptability: Insights from ASHRAE RP-884 and the Chinese thermal comfort database

Understanding indoor thermal environment characteristics, Occupants’ adaptability, and making a reasonable assessment based on thermal comfort standards are crucial for achieving energy-efficient and high-quality building environments. Sufficient data from the thermal comfort database serves as an important foundation for analyzing indoor thermal environments. The ASHRAE RP-884 database, a foremost comprehensive global thermal comfort database, has been pivotal in establishing and revising current standards like ISO 7730 and ASHRAE 55. Drawing from the ASHRAE RP-884 and the Chinese Thermal Comfort Database, this study strictly selected 20,074 and 33,775 valid data across varying building operation modes, and the analysis reveals significant differences between the indoor thermal environment characteristics in China and the RP-884 global database. The Chinese population demonstrates heightened adaptability, with 80% acceptable temperature ranges of 19.38 ℃ to 29.22 ℃ in cooled buildings, 15.99 ℃ to 27.26 ℃ in heated buildings, and 15.69 ℃ to 30.78 ℃ in naturally ventilated buildings, presenting a broader range than those in the RP-884 associated countries. Specifically, we found the thermal comfort zones defined in ISO 7730 and ASHRAE 55 standards may not fully accommodate the Chinese context. Besides, a thermal adaptation model tailored for China's naturally ventilated buildings was proposed based on the Chinese Thermal Comfort Database, with a slope of 0.45, surpassing the 0.31 of ASHRAE 55–2020 and 0.33 of EN 15251–2007. Lastly, potential reasons for the observed differences were analyzed and discussed.