Melting Evaluation of Phase Change Materials Impregnated into Cascaded Metal Foams with Regionalized Enhancement

Metal foam promotes the heat transfer of phase change materials (PCMs) in the penalty of reducing the energy storage density of the composite PCMs. In this work, the effects of constant porosity (0.96, 0.94, 0.92, or 0.90) and pore density (PPI) of metal foam on heat transfer of composite PCMs are studied. Melting rate could be enhanced by employing with low porosity copper foam. Furthermore, aiming to the right bottom phase changing "dead region", a regionalized enhancement strategy of cascaded metal foams is introduced. The dynamic melting performances of all the composite PCMs are comprehensively analyzed. The results reveal that the cascaded configuration is beneficial for optimization. Details show that the horizontal strategy enhances melting performance: a maximum of 17.98% reduction in total melting time could be reached when the rear part porosity is 90%. The energy storage density rate could be raised by 5.48%. Besides, the vertical strategy performs with a better average temperature uniformity of 0.441 and brings a lower temperature in the heated wall. To sum up, the regionalized enhancement of copper foam provides better performance in the phase change process. It shows significant potential for solar heat storage and thermal protection.