Biomimetic tree-shaped fins for a phase change cold storage system: Enabling cost-optimal charging in refrigerated transport

While phase change materials (PCMs) are pivotal for decarbonizing cold chain logistics, owing to their high energy storage density, their widespread adoption is critically hampered by an inherent bottleneck: low thermal conductivity. This limitation precipitates prohibitively long charging times, preventing the strategic use of economic incentives like time-of-use tariffs. To overcome this fundamental challenge, this study introduces a novel, biomimetic tree-shaped fin structure engineered to radically enhance heat transfer within a latent heat cold storage system (LHCSS). A validated, transient multiphysics model was developed to perform a coupled thermo-economic optimization, systematically investigating the geometry, number, and material of this biomimetic heat transfer architecture. The results demonstrate that the biomimetic fins dramatically accelerate the system's thermal response. An 8-fin configuration reduced total solidification time by 70.4% versus the baseline, while an optimized 10-fin design achieved the fastest time (1614 s) and the highest mean energy storage rate (532.47 W). This thermal enhancement yields superior economic performance, with the 10-fin design achieving a 310% higher techno-economic index. Critically, the rapid charging enabled by the biomimetic tree-shaped structure fundamentally reshapes the system's operational strategy. The accelerated solidification process allows full charging within short off-peak electricity windows, which is unattainable for conventional systems constrained by slow phase-change kinetics. Under time-of-use tariff optimization, this capability reduces operational electricity expenditure by approximately 76%. The economic advantage remains robust under realistic PCM and metal price fluctuations as well as varying peak–valley tariff spreads, confirming stable thermal economic superiority. This pioneering work is the first to bridge component-level biomimetic design with system-level economic dispatch for mobile refrigeration. It establishes a new paradigm, delivering a validated, economically compelling solution that leverages radical heat transfer enhancement to fully capitalize on dynamic energy tariffs.