Thermal performance analysis of lightweight building walls in different directions integrated with phase change materials (PCM)

Phase change materials (PCM) can improve the thermal performance of lightweight building walls (LBW), but the effect is not only dependent on the PCM parameters but also high on the heat exchange between the surface and the ambient environment. For actual buildings, there are differences in the outdoor thermal environment of the walls in different directions, especially the solar radiation intensity. Therefore, a small-scale lightweight building was made in this study and its thermal environment in different directions were tested. Then, the influence rules and suitability of PCM parameters on the thermal performance of LBW in different directions were analyzed by developing a typical two-dimensional heat transfer model. The results show that the application effects and suitable parameters of PCM in walls in different directions are different. PCM location (phase-transition temperature) is adapted to the middle (20–30 °C) for the east and south-facing wall, while the inside (18–28 °C) and outside (24–34 °C) is optimal for the west and north-facing wall. The thermal performance improvement with the most noticeable in the east and west-facing walls at suitable PCM parameters and their peak and average heat flux can be reduced by 62.8–66.4% and 28.2–29.5%, and delay time increased by 5–5.34h compared to reference wall