Achieving a thermal comfort condition for occupants of a building is the basic purpose of heating, ventilation, and air conditioning (HVAC) systems. However, since physiological conditions and satisfaction standards vary considerably from person to person, each individual normally has a different acceptable range of preferred air temperature. Among human body components, skin temperatures are most significantly related to thermal sensations, and they are controlled based on the human body’s thermoregulatory principle, i.e., homeostasis.
The main goal of this study was to better understand the relationship between facial skin temperature and human thermal sensation in order to determine appropriate conditioned air temperature settings. This can help in achieving thermal comfort by reading facial temperature as an input signal in the loop of the cooling and heating process. A series of human subject experiments were conducted in an environmental chamber at the University of Southern California. While the ambient air temperature was being regulated between 20 ºC and 30 ºC, temperatures of a user’s facial skin were measured at six points with an intermittent thermal sensation survey. Based on the analysed data, a thermal sensation model was developed as a function of facial skin temperature, its gradient, ambient environmental parameters, and a human factor.