Computational analysis of the melting process of Phase change material-metal foam-based latent thermal energy storage unit: The heat exchanger configuration

In the current study, the melting process of phase change material (PCM) embedded with nanoparticles and metal foams (MF) in a large scale shell-and-tube based latent thermal energy storage unit (LTES) has been numerically studied. Initially, the developed model was validated with experimental data. Then, the effect of Al2O3 (5%) nanoparticles addition and several MFs, i.e. Aluminum (Al), copper (Cu), Nickel (Ni) and Titanium (Ti), of different porosity (96–99%) on the performance of the melting process has been compared based on temperature and liquid fraction evaluations during the melting operation. The MF-PCM systems showed the best performance over the nano- and pure- PCM, with a huge reduction in the melting time. The beneficial effect of MFs for the melting process followed the order Cu > Al > Ni > Ti, which is the same order of the thermal conductivity. Increasing the metal foam porosity results in shorter melting time; however, since the surface temperature of the porous-PCM unit is almost constant for different metal foam porosities, a system with higher porosity (99%) is desirable. This study optimizes the design to enhance practical application performance and to reduce waste energy.