Experimental study on the influence of foam porosity and pore size on the melting of phase change materials

Experimental study was carried out to study the phase change heat transfer within a composite of phase change material (PCM) infiltrated high thermal conductivity foam. An experimental setup was built to measure the temperature profiles and capture the melting evolution of the PCM inside aluminum foams. Aluminum foams were used as the porous material, and low melting temperature paraffin wax was used as the PCM. It was observed from the results that the system parameters of the wax/foam composite had a significant influence on its heat transfer behavior. By using higher porosity aluminum foam, the steady-state temperature was reached faster as compared to the foams with lower porosity. Similarly for the bigger pore size foams the steady state was attained faster as compared to the smaller pore size foams. This was due to the greater effect of convection in both the higher porosity and bigger pore size foams. However, for the lower porosity foams the heater temperature was comparatively lower than the higher porosity foams due to greater heat conduction through the foam material. Therefore, an optimal value should be selected for the foam porosity and pore size such that the effects of both conduction and convection heat transfers can be completely utilized to have a greater and improved thermal performance for the wax/aluminum foam composite.