Heat and Moisture Transfer in Building Enclosing Structures

Abstract

AbstractNowadays, there are various mathematical models which give an opportunity to determine the moisture distribution inside building walls. It has to be stated that some models calculate steady-state moisture transportation in the capillary-porous media, while other models assess unsteady-state moisture movements. Equations of steady-state moisture regime usually can be usually solved by analytical expressions. It is certain that in terms of solving unsteady-state moisture transfer equations, scientists use numerical methods, which cannot be operated without computer. The discrete–continuous approach for evaluating the moisture behaviour of enclosing structures is proposed. Two computer programs were created. One of them calculated moisture regime by finite difference method using explicit difference scheme, whereas the second one assessed moisture behaviour by discrete continuous method using obtained analytical expression. As a result, efficiency of the discrete continuous method was demonstrated because the solution of the unsteady-state moisture transfer equation according to proposed method has similar quantity and quality distribution of moisture content with solution of the unsteady-state moisture regime by the finite difference method. It allows scientists and engineers to calculate moisture regime by analytical expression and not to use numerical calculations.KeywordsMoisture regimeMathematical modelDiscrete–continuous approachFinite difference methodEnclosing structures