Estimated thermal sensation models by physiological parameters during wind chill stimulation in the indoor environment

Thermal sensation is the occupants' response about the thermal variation of any given environment. Data regarding thermal sensation can be collected to enhance an air conditioner's capabilities to improve the thermal environment of an area. In this study, six physiological parameters, including skin blood flow (SBF), skin temperatures (forehead, arm, and hands) sweat areas and sweat pore diameters of the body were monitored during a two-step wind chill stimulation in an indoor environment. These physiological parameters were measured by a laser Doppler flowmeter, three surface thermometers, and a digital universal serial bus (USB) microscope. The sample group consisted of 12 undergraduate students who were recruited to be test subjects. The correlation coefficients between the aforementioned six physiological parameters and the Thermal Sensation Vote (TSV) were then analyzed. These physiological parameters were used to develop eight estimated TSV models. Of all the parameters measured for the TSV models, skin temperatures of the forehead and arms as well as SBF measurements provided the most accurate results. In contrast, sweat area measurements had the lowest accuracy under the experimental conditions of this study. Therefore, the estimated TSV models based on the skin temperature measured at the forehead or the combined physiological parameters would provide the most timely thermal comfort response of the occupants and facilitate the better intelligent control of an air-conditioning system for an indoor environment.