Experimental Study of Heat Transfer in a Reduced Scale Cavity Incorporating Phase Change Material Into Its Vertical Walls

In order to really assess the thermal performance of a wall incorporating phase change material (PCM), a reduced scale cavity has been monitored during two heating cycles. For each cycle, the heat source inside the test cell is switched “on” for 5 h and its setpoint is 38 °C and then switched off for 4 h. The outdoor air temperature is kept constant at a low temperature of 20 °C. Two walls are equipped with a PCM layer at different depths in order to study the optimal PCM location. The two other walls are wooden and glass to model a real building. The comparison between the four walls is made based on the absorbed heat fluxes and outside surface temperatures. The results show that the location of the PCM close to the heat source reaches its melting temperature and then reduces the surface temperature. At this location, the PCM layer stores the major part of the inlet heat flux. It takes 10 h to release the absorbed heat flux. However, the PCM layer, practically, does not have an effect on the surface temperatures and absorbed heat fluxes, when it is placed far from the heat source.