Heart rate variation and electroencephalograph - the potential physiological factors for thermal comfort study

Human thermal comfort researches mainly focus on the relation between the environmental factors (e.g. ambient temperature, air humidity, and air velocity, etc.) and the thermal comfort sensation based on a large amount of subjective field investigations. Although some physiological factors, such as skin temperature and metabolism were used in many thermal comfort models, they are not enough to establish a perfect thermal comfort model. In this paper, another two physiological factors, i.e. heart rate variation (HRV) and electroencephalograph (EEG), are explored for the thermal comfort study. Experiments were performed to investigate how these physiological factors respond to the environmental temperatures, and what is the relationship between HRV and EEG and thermal comfort. The experimental results indicate that HRV and EEG may be related to thermal comfort, and they may be useful to understand the mechanism of thermal comfort.Thermal comfort is closely related to the mental and physical health of indoor occupants. Most of the previous studies on this topic were based on the predicted mean vote (PMV) equations, the famous thermal comfort model developed by P.O. Fanger. Although the PMV model can well present the relationship between the conditions of thermal environment and human's thermal sensations, it can not explain essentially what the human's thermal comfort is. This study managed to identify the two physiological variables (e.g. heart rate variation and electroencephalograph) that might have potential relationship with human's thermal comfort. It will help us to understand the essentiality of thermal comfort better.