Numerical simulation of the human thermophysiological responses with a liquid circulating garment: Experimental validation and parametric study

Abstract

Liquid circulating garments (LCG) can effectively alleviate the heat strain of people in hot environments. This work used a human thermoregulatory model integrated with a thermal and comfort model to comprehensively study the design factors of LCG. The model was firstly validated by human trials and showed good simulation performance in predicting both thermophysiological and subjective responses with LCG in a hot temperature. Then a numerical parametric study was performed to examine the effect of inlet water temperature, clothing insulation, pipe length, and cooling mode on cooling performance under different hot environments. The results indicate that the comfortable inlet water temperatures are 22, 19, and 16 °C under 30, 34, and 38 °C environments, respectively for a standing person wearing an LCG with thermal insulation of 1.0 clo and water pipe length of 8 m. Higher clothing insulation is beneficial for reducing the core and skin temperatures in very hot environments (i.e., 38 °C). The pipe length has a significant impact on the cooling performance. Furthermore, compared to the continuous cooling mode, intermittent cooling in high frequency (i.e., time cycle period = 5 min) can mitigate the heat stress of wearers with less energy consumption. The study could provide a helpful guideline for designing LCG to offer better thermal comfort and energy-saving strategies for people in hot environments.