Enhanced thermal performance of cylindrical energy storage tanks with radial and longitudinal fins using phase change materials: A comparative numerical study

• Dual-wall boundary conditions reduced freezing time by 79.03 % compared to single-wall setups. • Radial fins excelled in early phase change due to focused energy transfer in central regions. • Longitudinal fins provided uniform freezing and superior performance at higher fin counts. • Performance trade-offs between radial and longitudinal fins were analyzed under equal fin volumes. • This study offers innovative insights into fin configuration optimization for TES systems. This study investigates the freezing process in cylindrical thermal energy storage (TES) systems enhanced with radial and longitudinal fins, using phase change materials (PCMs) to optimize heat transfer and improve energy storage efficiency. Two boundary condition configurations were analyzed: one applied to the inner wall and another to both the inner and outer walls. Numerical simulations demonstrated that applying boundary conditions to both walls significantly accelerated the phase change, reducing freezing time by 79.03 % compared to systems without fins. Results further showed that radial fins improved initial phase change efficiency but experienced performance drops at later stages due to uneven thermal resistance, while longitudinal fins exhibited more stable performance, with higher fin counts reducing freezing time by up to 58.63 %. These findings offer a comprehensive understanding for optimizing cylindrical TES systems, contributing to more effective design strategies for industrial and renewable energy storage.