A detailed experimental study has been performed to evaluate the heat transfer performance of a solid/liquid phase-change thermal energy storage system that includes porous metal foam. The phase-change material (PCM) and metal foam were contained in a vertically oriented test cylinder that is cooled at its outside boundary, resulting in radially inward freezing. As the PCM freezes, the solid/liquid interface moves inward from the surface of the test cylinder, and a thermal resistance layer is built up, resulting in a reduced heat transfer rate between the system to be cooled and the PCM. The porous material used in this research was intended to minimize the insulating effect of this thermal resistance layer. In the freezing case study, a one-dimensional mathematical model was developed, which considered heat conduction as the only mode of heat transfer. The effective thermal conductivity of the porous media saturated with solid eicosane was predicted utilizing several models and compared with the measured effective thermal conductivity. The results of this study are discussed in terms of the effectiveness of the metal foam as a heat transfer enhancement device.
Heat transfer performance and melting dynamic of a phase change material subjected to thermocapillary effects
