Numerical analysis of topological optimization and metal foam structure of phase change energy storage process for buildings

The application of phase change energy storage technology holds considerable significance in building energy management, but phase change materials have problems such as uneven heat transfer and low thermal conductivity. In this study, two passive heat transfer enhancement methods (novel topological fin and metal foam) are considered to improve it. The topologically optimized fin structure is constructed with the lowest average temperature as the optimization parameter, and the numerical model of copper metal foam is developed using a non-equilibrium thermal model. The impact of copper foam and topology-optimized fins on the heat release characteristics is comparatively analyzed. Results indicate that the novel topological fin structure, Case 5, with a 5% volume ratio, enhances the solidification performance within the refractory region. Furthermore, the solidification time for the same volume of metal foam, Case 6, is reduced by 8.47% compared to Case 5. However, the mean heat release rate and energy release are reduced by 3.81% and 9.95%, respectively. Consequently, the topological fin demonstrates superior thermal response and heat transfer efficiency compared to the metal foam under conditions of incomplete heat release. Further investigation into the pore density of the metal foam reveals that increasing pore density reduces heat release time and increases the release rate, albeit at the expense of total energy release.