Evaluation and optimization on heat transfer performance of a composite phase change material embedded in porous ceramic skeleton: A lattice Boltzmann study

Abstract

The thermal performances of phase change materials (PCMs) are of great importance to latent heat thermal energy storage applications. In order to improve the thermal properties, the composite PCM of inorganic salt embedded in porous ceramic skeleton was proposed and investigated in this study. The numerical model for the phase change process of PCM was developed by applying the lattice Boltzmann method. Simulation results indicate that the existence of porous ceramic materials could not only enhance the heat conduction of PCM but also hinder the convective heat transfer. In addition, the results show that Rayleigh number has a significant effect on the melting process of PCM. At low Rayleigh number, the existence of ceramic skeleton can significantly improve the thermal conductivity of composite PCM. However, at high Rayleigh number and porosity, the reduction of convective heat transfer might be greater than the heat conduction enhancement due to the addition of porous skeleton materials. By designing an appropriate non-uniform pore network of porous skeleton materials, further enhancement of heat conduction without obvious loss of convective heat transfer has been achieved. The research results obtained in this study could provide useful guidance for designing high-performance phase change energy storage materials.