A Study On Thermal And Moisture Transfer Through The Multilayer Garments In Cold Climate

In order to keep warm and resist cold in cold environmental conditions, people used to wear more garments so as to reach thermal comfort. Based on perspiring fabric thermal manikin, an investigation was undertaken to compare the thermal resistance of garments and their fabric. Then the relationship between heat and moisture properties through clothing ensemble and environment is explored. And thermal resistance and moisture resistance through clothing ensemble and each layer clothing are measured under condition of temperature at 10℃and relative humidity at 40%. Its results can be contributed to the evaluation of warm keeping and moisture transfer properties of clothing systems in a correct way so as to optimize the way to dress.The details of this paper are described as follows:At first, an investigation was undertaken to compare the thermal resistance of garments and their fabric from perspiring fabric thermal manikin and guarded hot plate apparatus. The results are shown that the two apparatus have good experimental accuracy. By the measurement of the dry heat loss, guarded hot plate apparatus is used to measure the thermal resistance value of fabrics, while perspiring fabric thermal manikin can measure the garments' thermal resistance value by simulating the human body. Fabric thermal resistance with the surface air layer resistance included measured by guarded hot plate apparatus is less than total garments' thermal resistance measured by manikin.Secondly, though many of the previous works have been performed to evaluate the thermal transport properties of cloth, they are all performed in normal temperature, and the results are different in cold climate. In this paper, the relationship between heat and moisture properties through clothing ensemble and environment is explored. Heat and moisture properties through clothing ensemble are measured by perspiring fabric thermal manikin under both conventional climate condition of temperature at 20℃and relative humidity at 65% and cold climate condition of temperature at 10℃and relative humidity at 40%. Moisture permeability index of clothing ensemble is also calculated. The results are shown that thermal resistance of clothing ensemble increases, moisture resistance of clothing ensemble decreases and the moisture permeability index of clothing ensemble increases when temperature and relative humidity decrease. Finally, thermal resistance and moisture resistance through clothing ensemble and each layer clothing are measured by perspiring fabric thermal manikin under condition climate of temperature at 10℃and relative humidity at 40%. It is found that the thermal resistance of a multi-layers clothing ensemble has definite statistical relationship with the thermal resistance of each layer. And it is found that the moisture resistance of a multi-layers clothing ensemble has definite statistical relationship with the moisture resistance of each layer. The results are shown that: effective thermal resistance, and intrinsic thermal resistance of the clothing ensemble are linearly with the arithmetic sums of effective thermal resistance, and intrinsic thermal resistance for each layer; and .effective moisture resistance, and intrinsic moisture resistance of the clothing ensemble are assumed to be the power function of the arithmetic sums of effective moisture resistance, and intrinsic moisture resistance for each layer. This research results can be contributed to the prediction for the thermal comfort of clothing ensembles by knowing the thermal and moisture resistance value of each layers.