Novel Design of a Personal Liquid Cooling Vest for Improving the Thermal Comfort of Pilots Working in Hot Environments

Wearing a liquid cooling garment (LCG) that offers near-zone cooling improves the thermal comfort of pilots working in hot environments. Four LCG samples with different arrangements of tubes for distributing liquid were developed. Based on the analysis of the overall and local cooling efficiency of the four LCG samples using manikin tests, another novel LCG with a horizontal-vertical combined tube was proposed to achieve optimal cooling performance. Human trials were conducted to check the novel LCG for improving the thermal comfort of pilots in a hot indoor environment (40 degrees C, 40% RH). The mean skin temperature of the subjects wearing the novel LCG was reduced by 1.9 degrees C in the 120-minute-duration flying simulation work compared to the no-cooling scenario, and the greatest decrease in skin temperature (i.e., 5.7 degrees C) was exhibited at the back waist. The thermal sensation at the upper body was improved to nearly neutral, and the heat stress level was reduced from moderate to slightly. The findings provide a guideline for designing personal LCG, thus benefiting the comfort and safety of pilots in hot cockpits.