Experimental investigation of thermal properties and moisture buffering performance of composite interior finishing materials under different airflow conditions

Abstract The thermal and humidity environment of indoor air affects the health and comfort of building occupants and the durability of building structures. One potential solution for moderating the thermal and humidity environment is provided by functional materials used for interior finishing, if it can passively buffer heat and moisture. Considering that airflow occurs at all times and locations in buildings, this study focused on the moisture buffering performance under different airflow conditions. A gypsum board was used as a hygroscopic material for interior finishing and was mixed with a microencapsulated phase change material (MPCM) to prepare composite hygroscopic MPCMs. The biomass painting material was another functional material for interior finishing and was prepared by blending scallop shell powder and a PCM slurry. Their thermal properties, such as the thermal conductivity and enthalpy, were tested, along with the hygroscopic properties, such as the pore-size distribution, equilibrium moisture content curve, and water vapor permeability. Scanning electron microscopy indicated that the MPCMs adhered well to and were retained on the laminated structure of the gypsum board. The moisture buffering performance of each sample was tested, and the results indicated that the maximum moisture absorption/desorption of each sample increased with the airflow rate. The ideal moisture buffering value (MBV ideal ) and practical moisture buffering value (MBV practical ) of each sample were determined and compared in different cases. Additionally, a simple linear model for MBV practical and the airflow rate was established to predict the influence of the airflow rate on MBV practical .