Thermal Analysis of Lightweight Liquid Cooling Garments Using Highly Conductive Materials

This paper presents the analysis findings of a study reducing the overall mass of the lightweight liquid cooling garment (LCG). The LCG is a garment worn by crew to actively cool the body, for spacesuits and launch/entry suits. A mass reduction of 66% was desired for advanced missions. A thermal math model of the LCG was developed to predict its performance when various mass-reducing changes were implemented. Changes included varying the thermal conductivity and thickness of the garment or of the coolant tubes servicing the garment. A second model was developed to predict behavior of the suit when the cooling tubes were to be removed, and replaced with a highly-conducting (waterless) material.

Findings are presented that show significant reductions in weight are theoretically possible by improving conductivity in the garment material. Also, a heat transfer bottleneck exists in the baseline garment through the tubes themselves that could theoretically be overcome and would result in further weight reductions. A third design modification involves inverting the garment, that is putting the tubes on the outside and conductive garment against the skin. This improves garment efficiency with additional weight reductions through the elimination of the comfort garment. These design changes permitted equivalent heat removal with a lighter garment. Results of the second model showed that a liquidless garment design is feasible theoretically, but will not yield weight reductions with current or foreseeable materials technology.