T-history characterization of phase change materials and heat transfer enhancement via metal meshes of varying Pores per Inch (PPI)

This study investigates the thermal behavior of Phase Change Material (PCM)–metal foam composites under base heating, a setup more representative of compact thermal energy storage (TES) and electronics cooling systems than the commonly analyzed side-heated arrangement. Metal foams with pore densities of 10, 20, and 40 PPI, all maintaining the same porosity, were infused with two PCMs (paraffin RT55 and RT64HC) and evaluated across different heat flux conditions. Initially, the thermophysical properties of three PCMs (RT42, RT55, and RT64HC) were determined using the T-history method. A reference case with pure PCM showed a pronounced thermal lag between the heat source and the material, while incorporating metal foam enhanced temperature uniformity and sped up the melting process. Findings indicated that pore density had minimal impact on total melting time, whereas the PCM type—particularly its melting temperature—played a significant role in determining duration. Heat flux emerged as the key influencing factor: increasing input power markedly decreased melting time, although the benefit diminished at higher flux levels. An empirical correlation from existing literature, originally formulated for side-heated foams, was applied to the base-heated scenario and successfully captured overall melting trends, but consistently underestimated completion times at higher heat fluxes. In summary, integrating PCMs with metal foams improves heat transfer, reduces localized overheating, and supports the design of more compact and efficient TES systems. Future research should aim to establish correlations for non-adiabatic conditions, investigate optimized foam structures, and scale the approach for real-world energy storage and cooling applications.