Analysis Of Thermal Protection Requirement In PCM Protective Garment Based On Different Metabolic Rates In Low-temperature Environment

This paper built a calculation model between the protective time of PCM and the application amounts of PCM in protective garment by analyzing the heat exchange between environment and the body-garment system. The theoretical model could be used to calculate the protective time of PCM by human metabolism rate, environment temperature and the amounts of PCM. It can provide reference for the design and usage of PCM protective garment which used in the special low temperature environment.Comparisons between the theoretical and experimental results shows good agreement.Based on the heat balance equation and the protective principle of PCM, the ways of heat production and heat loss were analyzed. After discussing the computing method of the factors in the equation, the calculation model between the protective time of PCM and the application amounts of PCM in protective garment was built. After that, suitable parameter values were measured and calculated on the basis of different conditions. Then 24 theoretical results were got according to the obtained parameters.To measured the experimental results of the protective time, the thermal protection experiment was designed according to the condition set by paper. After analyzing the theoretical results by 24 experimental results, The conclusion shows that:(1)The relative errors between theoretical results and experiment results are less than 5%, which are controlled in a certain range.(2)The body’s condition stays thermal equilibrium in the stage of latent heat release, which is in line with the condition of hypothesis.(3)Positivecorrelation exists between the protective time and the amounts of PCM when other conditions are equal. Finally, 5 parameters which are difficult to acquired in practice, are simplified. The simplification can improve the practicability of the model. The calculation model provides a method to calculate the amounts of PCM according to thermal protection requirement. It applies to low temperature environment without sun or other heat source, and there is no sensible sweating for the people who work there.