Thermal behaviors of latent thermal energy storage system with pcm and aluminum foam

A numerical investigation on LHTESS with PCM is accomplished. The PCM used is paraffin wax. To enhance the heat transfer inside the system a highly conductive material like metal foam and ceramic nanoparticles are used. The latter method of enhancement leads to a new class of material called Nano-PCM. The system under investigation is a typical 70 L water tank filled up with pure PCM or Nano-PCM and a certain number of pipes are located where the Heat Transfer Fluid (HTF) flows. The surfaces of the pipes are assumed at a constant temperature above the melting temperature of the PCM to simulate the heat transfer from the HTF. The enthalpy-porosity theory is employed to simulate the phase change of the PCM while the metal foam is modelled as a porous media that obeys to the Darcy-Forchheimer law. The ceramics nanoparticles are modelled with the single-phase model. The simulations are accomplished for charging-discharging process at different porosities of the metal foam and different concentration of the nanoparticles. The results show that the presence of the metal foam improves the heat transfer in the system respect to the addition of the nanoparticles, reducing the melting time more than one order of magnitude.