Thermal Requirement Analysis Of Phase Change Protective Clothing In Low Temperature Environment

In low temperature environment, thelack of a proper thermalprotection can causehuman body frostbiteor even cause death. In this paper, the computational method oftheoretical relationship between the phase change materials content in protective clothing,protective time and the working environment temperature was proposed when took intoaccount the comfort requirement of human bodies, clothingthermal properties and heat lossthrough clothing system. This theoretical model could be used to predictthe relationshipbetween the protective material content and theprotection time of phase change protectiveclothing. Experimentalresults showed good accordancewith the theoretical prediction.First, the reaction of the human body and the influence of low temperatureenvironment on the human bodywere analyzed in the low temperature environment.Theparaffin phase change materialswasselected as the research object.Phase transitiontemperature is25℃and30℃. The encapsulation method of phase change materials ismacroscopic packaging. Phase change protective clothing style was zippered vest anddesigned with stand collar, and not added the PCM in the side seam. The distributioninterval of PCM packaging is6mm.Then,thermal requirement of phase change protective clothingin low temperatureenvironment wasanalyzed and clothing system heat balanceequation with positiveheatsourcewas establishedaccording to the heat balance equation and heat transfer. Thecalculation formula of protection time of vest phase change protective clothing wasestablished in low temperature environmentby analyzingthe various influence factors of theheat balance equation and the value of each parameter method.After that, suitable parameter values were selected according to the conditionscalculation formula. Parameter values were put into calculation formula and the protectiontime was obtained in different conditions. The total number is16groups.Finally, the experiment was designed by selecting the same parameter values according to calculation. The experiment was divided into reality body experiment with16groups and a group of thermal manikin experiment. The phase change protective clothingprotection time，the skin temperature，the micro climate temperature were also tested aswell as human subjective thermal feeling. Experimental results showed good accordancewith the theoretical prediction, through comparing with the calculated value. Theprotective time calculation formula of the vest phase change protective clothing isapplicable when the human is standing statically orlight activity in low temperatureenvironment withno wind and no sun radiation.