NUMERICAL SIMULATION OF THERMAL ENERGY STORAGE WITH PHASE CHANGE MATERIAL AND ALUMINUM FOAM

摘要

A numerical investigation on Latent Heat Thermal Energy Storage System (LHTESS) based on a phase change material (PCM) is accomplished. The PCM used is a pure paraffin wax with melting over a range of temperature and a high latent heat of fusion. However, its thermal conductivity is very low (about 0.2 W/K m) and a method to enhance the heat transfer is putting the PCM into aluminum metal foam. The geometry of the system under investigation is a vertical shell and tube LHTES made with two concentric aluminum tubes. The internal surface of the hollow cylinder is assumed at a constant temperature above the melting temperature of the PCM to simulate the heat transfer from a hot fluid. The other external surfaces are assumed adiabatic or with heat losses toward the external ambient at assigned temperature. Two models are compared in reference to the heat transfer between the metal foam and the PCM, the Local Thermal equilibrium (LTE) and the Local Thermal non Equilibrium (LTNE). Results as a function of time for the charging phase are carried out for different porosities and assigned pore per inch (PPI). The results show the presence of metal foam improves significantly the heat transfer in the LHTES.