CFD Comparative Analysis of Conventional and Triply Periodic Minimal Surface (TPMS) Metal Foam Composites for Latent Heat Thermal Energy Storage

Lattice structures, particularly triply periodic minimal surfaces (TPMS), have attracted recent attention, as metal foam phase change material (MFPCM) composites within latent heat thermal energy storage (LHTES) systems, due to their large surface areas and lower thermal resistance. However, their thermal–hydraulic performance compared to conventional lattice and fin structures under identical porosity remain underexplored. In this study, computational fluid dynamics (CFD) was employed to perform a comparative analysis of metal foam structures that can enhance heat transfer in MFPCM composites within LHTES systems. Three triply periodic minimal surface (TPMS) lattices (Gyroid, Primitive, IWP), three conventional lattices (simple cubic, body-centered cubic, face-centered cubic), and a conventional fin design were evaluated under isothermal and isoflux heating scenarios. In each scenario, adding a metal foam speeds up melting compared to pure PCM. Under isothermal heating, the fin design melts the fastest (∼2.5 × pure PCM) and achieves the highest average heat transfer coefficient, followed closely by the IWP and Primitive TPMS lattices. Non-TPMS lattices designs melt more slowly, except the simple cubic performs comparably to the Gyroid due to its straight conduction paths. Under isoflux heating, all composites melt at similar times (within ~ 19%), but the fin and certain TPMS designs produce more uniform temperature distributions while strongly suppressing natural convection. Overall, despite the recent attention on TPMS structures, the current study shows that under the specified composite (number of unit cells, unit cell size, and porosity) conventional fins can provide the best balance of thermal performance and manufacturing simplicity for LHTES systems.