The influence of space discretization on the accuracy of numerical simulation of heat and moisture transport in porous building materials

It is well recognised that the accuracy of numerical solutions for coupled heat and moisture transport problems are highly dependent upon the space discretization regime adopted. While a range of possible space discretization methods are outlined in the literature, most of the commonly available simulation models for heat and moisture transfer through building constructions adopt the one-way expansion method. As part of the process of developing a new simulation model based on the Control Volume technique, the Authors have conducted a range of computer simulations to study the influence of space discretization on modelling results. Comparisons between different space discretization methods are presented which show that the two-way expansion method generally produces the best solution. This method has now been adopted by the Authors and has the advantage of avoiding the need to use extremely fine grids even when modelling complex building structures.