Calibration of the sweating function in JOS-3 model based on chamber experiment

Department of Building Environment and Energy Engineering, The Hong Kong Polytechnic University, Hong Kong, 999077, China

Abstract

Climate change brings about more frequent and more extreme heatwaves, which put people's health in jeopardy. Thermoregulation models serve as potentially effective tools to predict human thermal responses under extreme weather conditions. Based on these prediction results, health-rated guidance could be given. With open-source codes, the joint system thermoregulation model (JOS-3 model) boosts the development of thermoregulation model. However, there are still some deficiencies existing in the JOS-3 Model. As one of the major deficiencies, the sweating function of the JOS-3 Model is not triggered accurately and promptly, making it difficult to predict human thermal response accurately, especially in hot environment. Moreover, the total weight loss simulated by the JOS-3 Model is generally underestimated, which is also the consequence of an insufficient sweating function. The main purpose of this paper is to calibrate the sweating function of the JOS-3 model based on the data collected from a series of chamber experiments. During the chamber experiments, the skin temperature, core temperature and sweat rate of the subjects were constantly measured. The correlation of sweat rate with skin temperature and core temperature was later explored. The calibrated sweating function can make more precise predictions of local sweat rate, with most of the predicted values lying within the ±10% error band. The calibrated sweating function can also reduce the absolute value of the relative error of total weight loss by around 30% for 1-hour heat exposure. Therefore, the calibrated sweating function is more accurate and more conducive to evaluating the health risks that the extreme heatwaves pose to people.