Modelling of moisture and thermal transient behaviour of multi-layer non-cavity walls

This paper describes a dynamic model for evaluating the transient thermal and moisture transfer behaviour in multi-layer non-cavity wall constructions. Both heat and moisture transfer are simultaneously considered and their interactions are modelled. An implicit finite-difference scheme has been utilized to solve the temperature and air moisture content distributions across the different layers of the wall system. The model mathematical formulations pertaining to the method of solution are described together with interstitial condensation checking and node distribution criteria for transient moisture transfer. By employing the developed model, both the moisture transport process and the material moisture content within the different layers of a wall system can be evaluated at all possible material moisture conditions. The model is validated and proven to accurately predict the moisture behaviour of composite walls.