Thermal Mass Performance of Concrete Panels Incorporated with Phase Change Materials

Using the mass of a building as a thermal storage system can reduce the demand on the auxiliary heating and cooling systems of the building. Concrete combines a high specific heat capacity with a thermal conductivity that is appropriate for the diurnal heating and cooling cycle of buildings. The heat storage capacity of concrete can be enhanced by adding phase change materials (PCMs) which provide a high latent heat storage capacity. However the addition of PCM to concrete reduces the conductivity of the concrete which may affect the ability of a PCM-concrete panel to absorb and release heat within the desired time period. In this study two different methods of combining concrete and phase change materials were used to form PCM/concrete composite panels. The panels were exposed to radiative heat energy in a controlled environment for a specified time period during which the surface and internal temperatures of the panel were recorded. The temperature data together with the measured density and thermal conductivity was used to evaluate and compare the thermal mass behaviour of each type of PCM/concrete composite material. The addition of PCM to the concrete significantly increased the overall thermal storage capacity of the concrete despite reducing the density and thermal conductivity of the concrete.