Experimental and numerical study of heat transfer characteristics of a paraffin/metal foam composite PCM

Paraffin as a phase change material (PCM) has a great potential to be applied in many energy-related applications due to its appropriate melting temperature and large latent heat. The heat transfer characteristics during phase change of paraffin play a very key role in determining the thermo-fluidic performance. However, the drawback of low thermal conductivity will hamper the broaden application. In this study, we use copper foam to enhance the thermal conductivity of paraffin, and an experimental setup is built to study the phase change heat transfer characteristics. A two-temperature energy equation is used to describe the heat transfer characteristics of the paraffin/copper foam composite. The evolvement of solid-liquid interface and temperature variation during the melting process are experimentally measured and compared with the numerical results. It is found that there is a quite large temperature difference between the paraffin and ligament of copper foam, which is due to the thermal non-equilibrium effect in heat transfer between two phases. The good agreement between the experimental and numerical results indicates that heat transfer characteristics can be well depicted by two-temperature energy equation, which can be further used to depict the heat transfer in thermal energy storage or temperature control using composite PCM.