Experimental assessment on a kind of composite wall incorporated with shape-stabilized phase change materials (SSPCMs)

This research aimed to evaluate a kind of innovative composite-PCMs wall applicable in hot summer and cold winter regions. A kind of shape-stabilized PCMs constituted of expanded graphite, high-density polyethylene and paraffin wax was incorporated into cement mortar to prepare PCMs-bricks; mass percentage of the SSPCMs was 40%. Mechanical strength of the bricks was optimized. Two walls with a dimension of 1.5m × 1.5 m composed of the PCMs-bricks, regular vitrified bricks, respectively were built and tested in a medium-scale thermal chamber under different testing cases. Average compressive and bending strengths of the PCMs-bricks was 5.11 MPa and 3.70 MPa, respectively, so the bricks were applicable only in buildings with frame structure to bear load. Results showed that heat capacity of the PCMs-bricks was obviously greater than that of regular bricks from 18 °C to 25 °C. The PCMs-wall was in the phase change temperature range under mid-season conditions, and exhibited excellent thermal performance. But under winter and summer cases, the wall would never experience phase change and demonstrate vulnerable thermal behavior. Additionally, serious evaporative leakage of the PCMs was observed, and it is pointed out that regular preparation method of SSPCMs should be modified and developed to settle the leakage problem.