Numerical evaluation of indoor hygrothermal behavior with heat and moisture transfer in walls by analytical conditions

Abstract

Studies analyzing indoor thermal environments according to variables such as the outdoor climate, wall layer, and building composition have benn conducted using building simulations. However, previous analyses of hygrothermal performance considering moisture are insufficient. Therefore, this study propose a process for evaluating indoor hygrothermal performance according to parameters using two different simulations. First, heat and moisture transfer in walls (external and internal walls, roofs, and floors) was analyzed, and the hygrothermal performance of the indoor environment was investigated based on the hygrothermal behavior of walls. The heat and moisture transfer analysis showed that the relative humidity (RH) and water content were high inside the wall (E) and floor layers owing to regional climatic conditions. The results of the indoor environment simulation indicated a distinct distribution of temperature and humidity, owing to the heat and moisture fluxes from the inner surfaces. In addition, as a result of improving the hygrothermal performance by changing the building materials for exterior walls, the heat flux decreased by 30%, and the moisture flux decreased by 58%. These results confirmed that the boundary conditions for temperature and humidity required to evaluate indoor hygrothermal environments can be analyzed according to climatic conditions and wall layer compositions.