Numerical thermal performance assessment of phase change process in a PCM/foam-fins enclosure under various thermal conditions

Abstract

ABSTRACT The low ability of phase change material (PCM) to transfer thermal energy has created a serious challenge for the development of latent heat storage (LHTES) units. Embedding foam with high thermal conductivity material like copper has attracted significant attention. Besides, high porosity, lightweight, and easy usage are other important benefits of copper. However, its higher cost and decreasing effective volume of PCM led to the creation of amendments in the foam design. Employment of the foam in the form of fin or foam fin has emerged as an alternative method to benefit from the advantages of porous material and overcome its defects. In this study, various LHTES units with different numbers of foam fins have been simulated numerically and compared with pure PCM and fully foam PCM enclosures. Two practical boundary conditions including constant temperature and constant heat flux were examined for the designed systems. The obtained results demonstrated that foam fins have a remarkable effect on the thermal performance enhancement of LHTES under constant temperature boundary condition. For LHTES with six foam fins, 42% and 30% reductions in melting time were achieved for both types of boundary conditions including constant temperature and heat flux, respectively. At the beginning of charging process, a significant enhancement of input heat rate was proved for LHTES with 6 foam fins and fully foam up to 112% and 155%, respectively. In addition, the foam fins method provided some free volume of PCM to permit the falling out of natural convection of molten PCM.