Dynamic integration of phase change material in walls for enhancing building thermal performance -A novel self-adaptive method for moving PCM layer

Integrating phase change materials (PCM) into building envelopes has shown promises in reducing building heat load and shifting peak energy demands. However, traditional passive (static) PCM systems have limitations, including inefficient use of latent heat and missed opportunities for outdoor free cooling and heating, as fixed thermal insulation between the PCM and environment restricts the thermal transition. In order to enhance the utilization of the PCM and maximize free cooling and heating for interior thermal comfort, this study introduces a dynamic strategy for moving PCM (DSMPCM) integrated in building walls. This method allows the PCM layer to shift position within the envelope by compressing an air layer, depending on weather conditions. In this study, we compared the dynamic system ' s performance with static PCM wall and PCM-absent wall, demonstrating the DSMPCM ' s better performance in both summer and winter, where the monthly reduction in heat gain and heat loss are from 135.53% to 535.73% and from 2.92% to 58.76%, respectively. Also, the study identifies optimal PCM key thermal properties, air layer, and wall thicknesses under various climates. Additionally, we explored control strategy optimization to minimize envelope heat loads. These results confirm that properly configuring building envelope properties makes dynamic PCM integration a feasible and effective solution for energyefficient and sustainable building designs.