Effect of perforation density on twisted fins in a shell-and-tube latent heat thermal energy storage system during the charging process

Boosting the heat absorption efficiency in latent heat thermal energy storage (LHTES) systems continues to pose a major hurdle, primarily because phase change materials (PCMs) typically exhibit poor heat conduction properties. As a result, enhancing thermal transmission inside these systems is vital for accelerating energy accumulation and elevating overall operational effectiveness. This study employs computational fluid dynamics to investigate the charging thermal behaviour of PCM in a novel vertically oriented shell-and-tube LHTES system equipped with twisted fins of different configurations. The numerical model was developed using ANSYS 2024R1 and first validated against experimental data. The effectiveness of the design configurations was next evaluated by comparing non-perforated and perforated twisted fins with three perforation densities (sparse, moderate, and dense) against a baseline configuration without fins under identical operating conditions. The findings reveal that the charging time of baseline configuration was reduced by 46.50%, 49.30%, 53.52%, and 59.16% when using non-perforated twisted fins, sparsely perforated fins, moderately perforated fins, and densely perforated fins respectively. Compared with the non-perforated twisted fin design, the enhancement effectiveness of perforated fins increased from 1.06 for sparse perforations to 1.30 for dense perforations. This improvement indicates that increasing perforation density promotes additional convective mixing while maintaining adequate conductive heat transfer pathways, making densely perforated twisted fins the most effective configuration.