Condensation in three-layer waterproof breathable fabrics for clothing

摘要

This paper investigates the behaviour of condensation in three-layer waterproof breathable fabrics for clothing. An attempt has been made to consider water vapour transfer when condensation occurs within the three-layer waterproof breathable fabrics based on the simultaneous heat and mass transfer theory developed by Motakef and El-Maher and diffusion and condensation theory developed by Wijeysundera et al. According to the analysis made of existing theory, it is possible to model condensation within fabrics and laminates using the thermodynamic equations outlined in this paper, which can assist in predicting the performance of textiles and help to understand the comfort of performance clothing. It is noted that the condensation problem may be solved by changing some physical properties of a three-layer waterproof breathable fabric. The water vapour transfer out of the fabric can be improved, and consequently the formation of condensation reduced, by decreasing the thickness of the waterproof membrane and outer layer fabric or by increasing the average diffusion coefficient of the outer layer and membrane. A decrease in the thickness of the lining could increase the water vapour transfer from the hot side to the interface between the dry-wet regions, but this would also increase the condensation. Increasing the diffusion coefficient of the lining will also increase both water vapour transfer from the hot side and condensation.