Abstract
Liquid cooling garments (LCGs) are considered feasible cooling equipment to protect individuals from hyperthermia and heat-related illness when working in extremely hot and stressful environments. So far, the goals for the optimization design of LCGs are mostly from the perspective of enhancing its efficiency and working time. However, thermal comfort is the key factor that is often not considered. In fact, many situations may cause discomfort. For example, the inlet temperature of the liquid-cooling vest changes constantly resulting in the change of thermal states of the human body. So, it is very significative to develop a method to evaluate the performance of LCGs considering thermal comfort. In this paper, an uncomfortable time ratio was proposed to evaluate the performance of LCGs considering thermal comfort. A series of tests were conducted by a modified thermal manikin method to evaluate the thermal properties. According to the analyses, the duration working time was 82.77 min, while the uncomfortable time ratio was too large, up to 57.6%. It showed that the thermal comfort should be considered when optimizing the performance of LCGs. The influences of different parameters such as volume of ice, flowrate, inlet temperature on the performance of LCGs were investigated through orthogonal experimental design. The statistical analysis illustrated that the influence of the volume of ice on the uncomfortable time ratio is greater than that of flowrate and ambient temperature. It is concluded that this method is useful for the control and design of LCGs considering thermal comfort.
Using a Sweating Manikin, Controlled by a Human Physiological Model, to Evaluate Liquid Cooling Garments
