Practical moisture buffering effect of three hygroscopic materials in real-world conditions

Indoor humidity levels play an important role on occupants’ health, durability of the building envelope, and energy consumption levels. To achieve a sustainable, durable, healthy, and comfortable building environment, it is essential to maintain proper indoor humidity levels. Hygroscopic materials are typically used as finishing materials in some houses to control humidity, however, there is no criterion established to evaluate the moisture buffering effect of these. In this research, a series of experiments examining the moisture buffering effect of three types of hygroscopic materials were conducted in an actual room using different air change rates, hygroscopic material loading ratios, and moisture loads. A new index is proposed to evaluate the moisture adsorption effect (MBE_a) and moisture desorption effect (MBE_d) of hygroscopic materials at the room scale. Using the proposed index of MBE_a/MBE_d, multivariate linear regression analysis was performed to find the relationship between MBE_a/MBE_d and the major parameters that influence this. The model results show that the moisture adsorption/desorption effect of the hygroscopic materials in real-world conditions increased exponentially when the ambient air change rate decreased or the loading ratio of hygroscopic material increased.