Thermal performance of a novel building wall incorporating a dynamic phase change material layer for efficient utilization of passive solar energy

A new type of wall for building envelope is studied and its performance is analyzed in detail using computational fluid dynamics. The wall is designed to absorb and store passive solar energy during the day in winter and release it to the inside of the building at night. The salient feature of the wall is the presence of a phase change material (PCM) layer within the wall and its ability to switch its position with the insulation layer within the wall. During the day, the PCM layer is sandwiched between the outer brick layer and the insulation while after sunset the PCM swaps position with the insulation. The thermal performance of the proposed wall is compared with those of two analogous walls, one without PCM and the other with a similar static PCM layer. Results show the superior thermal performance of the proposed wall vis-à-vis the other two walls as it could save up to 89% of the energy normally used to heat the adjoining conditioned space during a severely cold winter. Moreover, this saving is realized by using only 0.32 kg of PCM per cubic meter of conditioned space, which is 50% less than previously used by other investigators.