  This work presents an efficient numerical method based on spectral expansions
for simulation of heat and moisture diffusive transfers through multilayered
porous materials. Traditionally, by using the finite-difference approach, the
problem is discretized in time and space domains (Method of lines) to obtain a
large system of coupled Ordinary Differential Equations (ODEs), which is
computationally expensive. To avoid such a cost, this paper proposes a
reduced-order method that is faster and accurate, using a much smaller system
of ODEs. To demonstrate the benefits of this approach, tree case studies are
presented. The first one considers nonlinear heat and moisture transfer through
one material layer. The second case - highly nonlinear - imposes a high
moisture content gradient - simulating a rain like condition - over a
two-layered domain, while the last one compares the numerical prediction
against experimental data for validation purposes. Results show how the
nonlinearities and the interface between materials are easily and naturally
treated with the spectral reduced-order method. Concerning the reliability
part, predictions show a good agreement with experimental results, which
confirm robustness, calculation efficiency and high accuracy of the proposed
approach for predicting the coupled heat and moisture transfer through porous
materials.
