Solidification enhancement of phase change materials using nanoparticles and metal foams with nonuniform porosity

Phase change material (PCM) is an essential component in latent heat thermal energy storage (LHTES). Using nanoparticles and metal foams could overcome the low thermal conductivity of PCM. In the present study, the effect of metal foams with varying porosity and nanoparticles on the solidification process of LHTES was numerically investigated. Parameters such as solidification time, temperature response rate, temperature distribution and exergy efficiency were analysed. As the volume fraction of nanoparticle was increased from 0 to 0.1, the solidification time was reduced by 30.15%, and the heat release exergy efficiency was increased from 55% to 60%. Compare with pure PCM, the solidification time of porous PCM with uniform porosity was reduced by 81.2%. Moreover, the heat release exergy efficiencies were 90.7% and 93.0% for the uniform porosity and the increasing porosity along x-direction, respectively.