Mechanical and Thermal Evaluation of Different Types of PCM-concrete composite panels

ABSTRACT: Thermal mass indicates the ability of a material to store and release heat and is a function of the heat storage capacity of a material. The thermal mass of construction materials can be used to reduce the energy required for heating and cooling buildings. The heat storage capacity of concrete can be increased by incorporating phase change materials (PCMs) into the concrete and hence providing additional latent heat storage capacity. Research was carried out to compare the thermal behaviour of two different types of PCM/concrete composite panels. The first type of panel was formed by adding microencapsulated paraffin to fresh concrete during the mixing process. The second panel was formed by vacuum impregnating butyl stearate into lightweight aggregate which was then included in the concrete mix. This study aimed to establish which type of PCM/concrete composite material was most effective at improving the thermal mass behaviour of the panel and also to evaluate the effect that the PCM had on the relevant properties of concrete. 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. It was determined that the concrete containing the lightweight aggregate/PCM was more effective at increasing the thermal storage capacity up to a depth of 100mm.