Thermal performance analysis of novel bionic fins in a concentric three-tube latent heat storage system

Latent heat storage emerges as a highly promising energy storage technology within renewable energy applications, offering superior energy density and more stable temperature profiles compared to sensible heat storage. Enhancing the overall thermal performance of latent heat storage systems can be effectively achieved through the incorporation of fins, which represent the most straightforward and efficient method. Nonetheless, progress in the exploration of fin structural morphology has been sluggish despite extensive research efforts. This study introduces an innovative Composite Fishbone Fin (CFBF), inspired by the skeletal structure of fish and the leaf morphology of rabbit umbrellas from the Asteraceae family, derived from meticulous observational analysis. Numerical simulations were employed to examine 21 distinct fin sizes and configurations alongside four different fin arrangement patterns. The enthalpy porosity method was utilized to accurately model the heat transfer and melting dynamics of the phase change material (PCM). The investigation quantitatively assessed the impact of fin geometric parameters and curvature angles on system performance. Findings reveal that within a Horizontal Triple-Tube Latent Heat Storage system (HTTLHS), the implementation of the novel CFBF reduced PCM melting time by 47.1 % compared to traditional rectangular fins and by 74.8 % relative to finless systems. Furthermore, optimal thermal performance was achieved when the CFBF featured large triangular fins measuring 18.75 mm in length and small triangular fins of 1.5 mm, each forming a 60° angle. This configuration maximized the synergistic effects between heat transfer and PCM liquid phase movement. Additionally, adopting the proposed fin arrangement in the HTTLHS decreased PCM melting time by 13.2 % and elevated the average Nusselt number by 15.5 %, thereby significantly boosting the heat transfer rate. This research not only advances the theoretical understanding of biomimetic fin mechanisms in latent heat storage systems but also offers an innovative solution for thermal energy storage and management in emerging industrial applications.