A front tracking method for melting of phase change materials.

Phase change materials (PCMs) have received considerable attention in recent years since they can tackle the time mismatch between energy supply and demand. During melting of PCMs, density changes create buoyancy forces resulting in an upward melted PCM motion, i.e. natural convection. However, many numerical studies and well-known methods (for instance the ε-NTU method) neglect the natural convection due to its modeling complexity. Effective thermal conductivity method simply accounts for the natural convection by an artificial increase of the thermal conductivity value. Nevertheless, obtaining the value is time-consuming and requires experimental data. Besides, it does not provide any information about the melting front location. In this study, a novel front tracking method is presented for PCM melting in horizontal shell and tube heat exchangers. The method considers separate melting fronts for the upper and lower halves and is simple enough to compete with and replace the effective thermal conductivity method.