To enhance the efficiency of phase change heat storage, this study investigates the synergistic effects and parameter interactions of a coupled strategy integrating fins, metal foam, and nanoparticles. A validated numerical model is developed for a shell-and-tube heat storage unit. The influence of porosity and pore density of metal foam, as well as Al2O3 nanoparticle concentration, on melting behavior, heat storage rate, and fluid flow features are systematically analyzed. Results indicate that reducing porosity significantly enhances heat conduction, shortening the complete melting time by up to 53.71%. Conversely, increasing pore density markedly suppresses natural convection, reducing the average liquid velocity by 64.62% and consequently extending the melting duration. The incorporation of nanoparticles consistently improves thermal performance; specifically, a 15% concentration reduces the melting time by 25.49%. Notably, a strong synergistic interaction is revealed. The enhancement of nanoparticles is more pronounced in metal foams with lower intrinsic conductivity, yielding an average additional enhancement of 17.24%. The optimal configuration identified in this study comprises metal foam with a porosity of 0.98 and a pore density of 10 PPI, coupled with 15% nanoparticles, achieving a heat storage rate 51.47% higher than the least efficient design. These findings elucidate the underlying coupling mechanisms and provide practical guidelines for the multi-parameter optimization of high-performance composite PCM-based thermal energy storage systems.
Hu et al. (Thu,) studied this question.