Moisture transfer characteristics of the wall with phase change material

The thermal performance of building walls could be improved by using phase change material (PCM), and there is already a lot of research about the heat transfer characteristics of PCM walls. However, the moisture transfer characteristics of PCM walls have rarely been studied. It is known that the heat transfer and the moisture transfer in the walls are highly coupled, and the moisture transfer process will also be affected when the wall is integrated with PCM. Therefore, a coupled heat and moisture transfer model for the walls with PCM was developed in this paper. The model was firstly validated by the experimental results, and then, it was used to investigate the characteristics of the moisture transfer in the PCM walls. Two series simulations, with different boundary conditions, were conducted. The results showed that the PCM not only had effects on the heat transfer in the wall, but also had effects on the moisture transfer in the wall. Compared with the wall without PCM, the peak relative humidity and the peak moisture flux of the wall with PCM were both small. Compared with the relative humidity fluctuation range of the wall without PCM, it was 77.03% lower when the wall contained 50% PCM. Compared with the moisture flux fluctuation range of the wall without PCM, it was 63.61% lower when the wall contained 50% PCM. The condensation risk in the wall could be reduced by using PCM.