Fin geometry influence on the performance of a latent heat thermal energy storage

With the growing need to reduce carbon emissions, renewable energy sources (e.g., solar and wind power) have gained significant attention in modern energy applications. In particular, thermal solar energy allows for the generation of high power but has the disadvantage of not being continuously available for a period of 24 hours. The deployment of advanced and efficient energy storage systems is critical in solar power plants to support grid stability and ensure an uninterrupted energy supply. Among the different storage strategies, Latent Heat Thermal Energy Storage (LHTES) stands out for its high energy density, which makes it particularly suitable for integration into Concentrated Solar Power (CSP) plants where energy continuity is essential. LHTES systems provide a simple, cost-effective, and environmentally friendly method of storing large amounts of thermal energy, with significant weight and volume reductions compared to other thermal storage solutions. An interesting research challenge is identifying the number and geometry of fins that improve heat exchange within LHTESs. In this study, different fin configurations are evaluated using numerical simulations to identify the best one. The first step was to validate the developed numerical model by comparing the results in terms of PCM melting time and temperature trends with the experimental results. A comparative analysis is then performed to identify which of the studied configurations leads the LHTES to charge in the shortest time, comparing the total melting times of the PCM with those of a reference case without fins. This study focused on improving heat transfer by varying the geometry of the annular fins through CFD analysis. Numerical simulations showed that increasing the height and number of fins improved heat transfer and, consequently, the thermal power absorbed by the LHTES, reducing the total PCM melting time. However, the performance improvement appears to be limited by the overall size of the system. Therefore, cost and manufacturing considerations should be taken into account in the design process.