Heat and moisture transport in wooden multi-composite panels. Dynamic study of the air layer impact on the building envelope energetic behavior

Heat and moisture transfers in the building envelope play a significant role in the energetic performances of a construction. In the present study, the dynamic behavior of a multi-composite wooden panel, including an air layer, is considered through heat and mass transport calculations. To address this problem, a vertical channel filled with humid air between hygroscopic walls was considered. Balance equations for mass, momentum, energy and vapor are solved taking into account conduction, convection, radiation, diffusion and condensation mechanisms. The transient evolutions of temperature, heat fluxes and humidity were observed versus several climatic parameters through a set of different boundary conditions. Realistic hygroscopic material and humid air properties varying with temperature and vapor mass fraction were also taken into account.