Thermal Comfort and Sensitivity of Different Body Parts Exposed to Local Infrared Radiation

Infrared radiation equipment, as a typical personal comfort system (PCS) unit, could effectively improve human thermal sensation vote (TSV) in cold environments. It could also be positioned diversely and controlled independently to meet personalized thermal requirements. However, the heat transfer principle of infrared radiation differs from thermal convection and conduction. Most parts of the human body were covered by clothes in winter; thus, the thermal responses differed from those uncovered. As a result, studies on the thermal responses and thermal sensitivity of different parts with clothing to local radiation were limited. An experiment was conducted at the indoor air temperature of 18°C in winter, during which five body parts were stimulated by infrared radiation at the intensity of 4 and 20 W/m 2 . Subsequently, the indoor environment and physiological parameters were measured. Meanwhile, the local and overall thermal responses of the human body were collected with questionnaires. Furthermore, the calculation method based on thigh sweating rate was determined as an approach to assess the sensitivity of each body part to infrared radiation more precisely. In terms of this method, the chest was more sensitive to infrared radiation than limbs, and the intensity of the infrared radiation had greater impacts on chest sensitivity while fewer effects on limbs. These findings could help improve the reliability in predicting and evaluating human thermal responses to infrared radiation environments and also provided references for the applications of infrared radiation PCS devices.