Innovative arrangement of circular angled fins for maximizing the discharge performance of triple-tube heat storage systems

Abstract

Abstract This study introduces a novel triple-tube latent heat storage system enhanced with circular angled fins to improve solidification and heat recovery performance. The fins are arranged in staggered pattern with alternating upward and downward orientations on both sides of the PCM shell. A validated numerical model was developed using the enthalpy method to simulate the intricate heat transfer and phase change physics. Effects of circular fins geometry and operating conditions were systematically quantified on discharge rates and temperature uniformity. Four fin dimension cases (thickness × length): (2 × 5), (1 × 10), (0.66 × 15), and (0.57 × 17.5) mm2 were analyzed. The results demonstrate that fins with greater length and reduced thickness exhibit superior performance due to enhanced heat transfer capabilities, resulting in quicker solidification and faster heat retrieval. The longest 17.5-mm fins, achieving full solidification in 1973 s with 44%, 19%, and 1.9% quicker than cases with 5-mm, 10-mm, and 15-mm long fins, respectively. Incorporating an additional fin upward further reduces the solidification time by 4.5% while improving heat recovery by 3.6%. The 17.5-mm long fins increase heat discharge by 48% and outlet heat-transfer fluid temperatures by 39% versus straight fin baselines. Lower inlet heat-transfer fluid temperatures (10°C vs 20°C) reduce PCM solidification times by 31% (1755s vs 2554s) while increasing heat recovery rates by 57% (56.3 W vs 35.8 W). Overall, the integrated angled fins create a customizable latent heat storage system with greatly intensified heat transfer and thermal performance compared to conventional shell-and-tube arrangements.