The thermal sensitivity (Griffiths constant) of occupants for naturally ventilated buildings in China

Abstract

The thermal sensitivity (Griffiths constant, G value) of occupants is a crucial parameter in the adaptive thermal comfort domain, which affects the neutral temperature and adaptive models. In existing studies, the Griffiths constant is typically 0.5 °C⁻¹, which is derived mainly from office buildings. There are few studies on whether the use of 0.5 °C⁻¹ is suitable for all buildings and what factors influence human thermal sensitivity. This study derived the Griffiths constant based on the field survey for naturally ventilated buildings in China, and the factors influencing the G value were deeply analysed. Instrument tests and subjective questionnaires were carried out simultaneously in the survey. There were 1448 valid participants from October 2021 to May 2023. The results indicate that the Griffiths constant varies across different types of buildings: 0.261 °C⁻¹ in the dormitory and 0.318 °C⁻¹ in the library. The gender difference in G values is statistically significant. The thermal sensitivity of females is 9.4 % greater than that of males. The Griffiths constant increases with increasing indoor operative temperature and decreases with increasing clothing insulation within the relatively comfortable thermal environment. Thermal perception significantly affects the Griffiths constant. Notably, the more comfortable the conditions are, the greater the thermal sensitivity. The neutral temperature calculated from the G value obtained via field surveys is more accurate than that from the universal G value. This study enriches adaptive thermal comfort theory and provides a valuable reference for the accurate establishment of the adaptive model of the Griffiths method.