Numerical investigation on latent thermal energy storage in shell and corrugated internal tube with PCM and metal foam

A numerical investigation on Latent Heat Thermal Energy Storage System (LHTESS) based on an aluminum foam totally filled with 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. The LHTESS geometry under investigation is a vertical shell and tube. The corrugated internal surface of the hollow cylinder is assumed at a constant temperature above the PCM melting temperature. The other external surfaces are assumed adiabatic. The paraffin wax phase change process is modelled with the enthalpy-porosity theory, while the metal foam is considered as a porous media obeying to the Darcy-Forchheimer law. Local thermal non-equilibrium (LTNE) model is assumed to analyze the heat transfer in the metal foam. The governing equations are solved employing the Ansys-Fluent code. The numerical simulations results, reported as a function of time, and concerning the LHTESS charging phase, are compared in terms of melting time, average temperature and energy storage rate. The corrugated internal surface effect is analyzed with respect to the wavelength and wave amplitude of the corrugation.