Improving the thermal performance of a spherical latent thermal energy storage using innovative fins and porous media

The performance of latent heat thermal energy storage (LHTES) systems can be significantly enhanced by improving the thermal properties of phase change materials (PCMs). Today, these systems serve as a sustainable energy resource and find applications in various sectors, including energy conservation in buildings, household hot water systems, air conditioning units, peak load reduction, waste heat recovery, and biomedical applications. This paper investigates the effects of fins and metal foam on the melting and solidification rates of PCM within a spherical latent heat thermal energy storage unit (LHTESU). To assess the impact of fin geometry on energy storage efficiency, three types of fins were tested: fins with a constant length, fins with a variable length, and curved-shaped fins. Additionally, three different porosity levels of metal foam were considered. A finless reservoir filled with PCM was used as a baseline and benchmark to evaluate the performance enhancements provided by the different fin and metal foam configurations. The results indicated that utilizing seven fixed-length fins with a thickness of 1 mm represents the most effective configuration for increasing melting and solidification rates among the constant volume fraction cases, leading to reductions in melting and solidification times by 58.76% and 72.66%, respectively. Furthermore, incorporating metal foam significantly improved the phase change rate of the PCM, achieving reductions in melting time by 89.11% and solidification time by 94.96% when 85% porosity was used. These results highlight the potential of advanced fin designs and porous media in significantly enhancing the thermal energy storage efficiency, offering promising insights for future sustainable energy technologies.