Investigation on heat and moisture transfer in bio-based building wall with consideration of the hysteresis effect

Two mathematical models describing heat and moisture transfer in porous media were used to predict the hygrothermal behavior of a new type of bio-based materials made of date palm concrete (DPC). The finite element method was used for the resolution of partial differential equations and numerical results were compared to experimental data considering similar conditions of temperature and relative humidity through the DPC wall. At first, a mesh sensitivity analysis was carried out and the optimum mesh configuration was determined. Afterwards, the hysteresis effect was implemented in the models and its influence on the variation of the relative humidity through the wall was discussed. The results revealed that the proposed models globally provided satisfactory results for the DPC wall, with an improved accuracy when considering the hysteresis effect. Finally, a comparison in terms of thermal insulation and moisture buffering capacity between DPC and a classical building material was performed numerically. Results showed that the new bio-based wall is very promising and can contribute to mitigate temperature variation and ensure hydrothermal comfort in buildings.