Impact of coupled heat and moisture transfer on indoor comfort and energy demand for residential buildings in hot-humid regions

Abstract

Moisture significantly affects indoor thermal comfort and energy demand. However, the coupled heat and moisture transfer (HAMT) effect inside the wall assemblies is often ignored in building performance calculations. To quantify its impact on building performance under hot and humid climates, the thermal environment and energy demand of an apartment in Guangzhou (China) were evaluated with and without HAMT finite element algorithm, respectively. The HAMT effects are quantified and analyzed in different periods. Different boundary conditions regarding climate uncertainty, wind-driven rain effect, and wall solar absorptance are considered. The results show that under naturally ventilated conditions, ignoring the effect of HAMT in walls can lead to an overestimation of indoor operative temperature by 1.2 °C in summer and an underestimation of 1.7 °C in winter. The deviation in indoor operative temperature calculated by the two models is noticeable from noon to midnight. On the other hand, cooling and dehumidification demand energy demand can be underestimated by 8.4% and 12.4%, respectively, without consideration of HAMT. The HAMT also increases the probability of high hourly energy demand for cooling and dehumidification under the HAMT effect. These findings emphasize the importance of considering the HAMT effect when evaluating building performance in hot and humid regions.