Integration of water sorption hysteresis for heat and mass transfer modeling

In the present work, the impact of water sorption hysteresis on the coupled heat/moisture transfer of building materials is investigated. After a review of the literature, the independent model of Mualem was identified and integrated into a simulation tool for coupled transfers. Then, a comparison between the simulation (with and without hysteresis) and experimental results was carried out for temperature, partial vapor pressure and relative humidity. This comparison shows that the integration of Mualem hardly changes the simulations. Further, this model has been modified and integrated into the same tool. The modified model has produced more convincing results as the error percentage of the relative humidity has been divided by a factor 2 (RH presents the highest error compared to other parameters). An analysis of the obtained results has revealed another hygrothermal parameter which is often neglected and could impact the hygrothermal modeling: the complementary sorption heat.

Automated summary

This study investigates the impact of water sorption hysteresis on the heat/moisture transfer of building materials. The Mualem model is integrated into a simulation tool, and a comparison is made between simulations with and without hysteresis, and experimental results. The integration of Mualem hardly changes the simulations, and the modified model produces more convincing results with a reduced error percentage in relative humidity. Additionally, an often neglected parameter that could impact hygrothermal modeling is identified.