Thermally limited wood moisture changes: relevance for dynamic vapour sorption experiments

In this research, an analytical model is developed for the study of thermal effects on transient uptake of moisture by wood exposed to a stepwise relative humidity (RH) change. This model specifically addresses the effect of the latent heat injection (withdrawal) during adsorption (desorption) on the equilibrium wood moisture content. It is explained that this inherent effect associated with wood moisture changes dominates at high RH in slow kinetic processes having time constants up to a few hundred minutes in 20 mg wood samples. In this dynamic range, the predicted RH dependence of the time constant is confirmed by dynamic vapour sorption experiments.