Thermal performance enhancement of phase change material melting using innovative fins

Enhancing PCM melting is crucial for improving thermal performance in energy storage systems, especially for thermal management and renewable energy applications. This study numerically examines PCM melting in a rectangular enclosure with different fin geometries, including rectangular, constructal, and tree-shaped fins. Key performance indicators such as liquid fraction rate, melting time, and heat transfer rate are analyzed. A numerical model was developed using commercial CFD software where validation against experimental data confirmed the model's reliability, supporting its effectiveness in optimizing thermal energy storage. The findings reveal that the addition of fins significantly enhances the liquid fraction and reduces the melting time of the PCM. Among the tested designs, tree-shaped fins exhibited the best performance, achieving complete melting within 130 min and 67% reduction in melting time compared to the unfinned enclosure. The use of rectangular and constructal fins decreases the melting time by 41%, and 53%, respectively. The heat transfer rate was highest at the onset of melting and gradually declined over time. Tree-shaped fins also demonstrated superior energy storage capabilities, outperforming constructal, rectangular, and unfinned configurations. The study highlights the role of buoyancy-driven flow in the melting process, where the melted PCM rises to the top of the enclosure. These results underscore the potential of novel fin geometries, particularly tree-shaped fins, to optimize thermal energy storage systems.