Simulation of PCM‐saturated porous solid matrix for thermal energy storage using the phase‐field method

Abstract

AbstractLatent heat storage systems using phase change materials (PCMs) are considered an attractive technique for storing the available thermal energy due to their high energy storage capacity, compactness and ability to store heat at an almost constant temperature. However, the PCMs suffer from their low thermal conductivity that affects the heat transfer rates and leads to slow charging and discharging processes. Therefore, many approaches have been adopted for improving the low thermal conductivity of PCMs. In the underlying research work, a latent heat storage medium using a PCM‐saturated highly conductive porous metal foam is being studied. High porosity cellular metal foams are proved to be promising materials for enhancing the heat transfer performance of the PCMs due to their high surface area to volume ratio, ultra light weight and relatively high thermal conductivity. A macroscopic description of the PCM‐saturated porous material with intrinsically coupled and incompressible solid and fluid constituents is presented, based on the Theory of Porous Media (TPM). The heat transfer process between the metal foam and the PCM is described using the local thermal non‐equilibrium model, where the phase‐field method (PFM) is employed to account for the phase change process. The PFM relies on specification of the free energy density function and employs a phase‐field variable that defines the state of the material (solid or liquid). Finally, numerical examples using the finite element method are presented to show the ability of the phase‐field‐porous media approach in simulating the phase change problems on the macro scale.