Characterizing the performance of a single-layer fabric system through a heat and mass transfer model - Part II: Thermal and evaporative resistances

Abstract

In Part I of this work, a heat and mass transfer model was developed to calculate the thermal and evaporative resistances of a single-layer fabric system. Using this model, the effects of environmental conditions, air gap, and material properties on the thermal and evaporative resistances have now been studied. The thickness of the air gap and that of the fabric layer were shown to contribute significantly to both the thermal resistance and evaporative resistance. The occurrence of natural convection in the air gap can cause decreases in thermal and evaporative resistances, and needs to be considered to determine the optimal air gap thickness. The porosity of the fabric layer has a distinct effect on the two resistances, and is an excellent property to help achieve both thermal protection and comfort. This work provides the fundamental basis for the optimization of garment fit and material properties to achieve good performance of the clothing system.