CALCULATION OF MOISTURE ABSORPTION AND DESORPTION TRANSFER FUNCTION IN BUILDINGS

摘要

In this paper, a transfer function approach has been described to calculate dynamic moisture absorption and desorption by building materials in the hygroscopic range, and the dynamic moisture absorption and desorption processes have been theoretically modelled. Their surface, vapour pressure and moisture absorption and desorption flux can be evaluated by this approach. It has turned out mathematically that the material surface attains instantaneous moistur equilibrium with the surroundings at high Biot nuniber(Bi→∞) and that the material moisture behaviour can be described through a lumped-parameter modelling at low Biot number(Bi→0). For building materials at moderate Biot number, comparisions with experimental results and numerical solutions have shown satisfactory agreement with the proposed approach. Using this aproach, the dynamic responc of moisture absorption/desorption in building interior materials to the variation of indoor air humidity and the dynamic effect of moisture absorjption and desorption by building interior materials on indoor air humidity and latent space cooling load can be simultaneously calculated.