Heating Performance and Energy-Efficiency Evaluation of a Personal Heating Device: Numerical Simulation and Experimental Validation

In southern China, where there is no district heating in residential buildings, the thermal comfort of indoor occupants cannot be guaranteed in winter due to the high energy consumption of whole-space heating. Foot Heating Pad (FHP), as a Personal Comfort System (PCS) device, enables occupants to improve thermal comfort with less cost. In this study, the effects of local heating by FHP on foot skin temperatures and thermal comfort were investigated, and the energy-efficiency performance of FHP was analyzed. A heat transfer model of human foot, which consists of four layers of body tissues, was established to simulate the foot temperatures under continuous and intermittent heating, and the numerical simulation of the model was accomplished using ANSYS. Besides, an FHP (36 W) based on Peltier heater was proposed and developed to heat the foot, and a climate chamber experiment involving 16 subjects was performed to collect subjects’ thermal comfort votes at three ambient temperature conditions of 8 °C, 11 °C, and 14 °C. The simulation results show that the foot skin temperature was significantly enhanced, and the plantar skin temperature increased by seven Temperature (K). Besides, there was no significant difference in foot temperature distribution between intermittent heating and continuous heating. However, the experimental results indicated that continuous heating was more effective in enhancing subjects’ thermal comfort and was able to ensure a neutral overall thermal sensation in a 14 °C environment. The Corrective Power (CP) of FHP was 7K and the Corrective Energy & Power (CEP) was 5.1W/K. This study is expected to provide guidance for the optimization design of PCS devices.