Organic phase change materials (PCMs), such as paraffin wax, have shown great potential for their utilization in latent heat thermal energy storage systems (LHTES). However, due to their low thermal conductivity, they are often hybridized with high thermal conductivity metal foam, resulting in metal foam-PCM composites (MFPCMs) with enhanced heat transfer features. Conventional metal foam is usually idealized using the Kelvin cell. Owing to the recent advances in 3D printing, any complicated topology can however be easily manufactured, which paves a pathway for other complex cell types to be utilized in such energy systems other than Kelvin cell. In this exploratory work, three Triply Periodic Minimal Surfaces (TPMS), i.e., Gyroid, I-graph and wrapped package-graph (IWP), and Primitive cells, are (to the best of the knowledge of the present authors), used for the first time, as skeleton for MFPCMs composites to enhance the effective thermal conductivity of conventional PCMs. Transient numerical simulations were performed to compare the thermal energy storage performance of the used TPMS-based PCM composites with their counterpart based on the conventional Kelvin cell. All structures were tested at the same porosity level and unit cell size of 90% and 7 mm, respectively. Simulations were done under two boundary conditions namely isothermal and isoheat flux conditions. Steady state simulations were also performed to assess the effective thermal conductivity of the used MFPCM composites at temperatures below the melting temperature of used PCM (pure conduction). The obtained results stress that the effective thermal conductivity of MFPCMs strongly depends on the cell type and its unique architecture and not only on the cell porosity where significant increase in the effective thermal conductivity of the MFPCMs composites was achieved when the three TPMS structures are used. Under isothermal condition while considering the Kelvin-based MFPCM as the baseline case, the PCM melting time was reduced by approximately 31% for the Gyroid, 40.3% for the IWP, and 35.3% for the Primitive-based MFPCMs. In isoflux case, the PCM melting time did not show dependence on the type of metal foam structure. However, by considering the temperature homogeneity as a performance indicator (quantified by the maximum and minimum temperature difference in PCM domain), Kelvin-based MFPCM showed the highest value for the difference (least homogenous) whereas, IWP-based MFPCM on average was almost 5 K lesser than the Kelvin-based MFPCM during the entire melting process. Therefore, TPMS structures showed superior performance than the Kelvin cell, let alone than the case of PCM alone, which makes them promising candidates for potential utilization in LHTES applications.

有机相变材料（PCM），例如石蜡，已显示出在潜热热能存储系统（LHTES）中的巨大利用潜力。但是，由于它们的低热导率，它们经常与高热导率的金属泡沫混合，从而导致金属泡沫-PCM复合材料（MFPCM）具有增强的传热特性。常规的金属泡沫通常使用开尔文（Kelvin）孔进行理想化处理。由于3D打印的最新进展，但是任何复杂的拓扑都可以容易地制造，这为开尔文电池以外的其他复杂电池类型在此类能量系统中利用铺平了道路。在这项探索性工作中，三个三重周期最小曲面（TPMS），即，陀螺仪，I型图和包裹式图形（IWP），以及原始单元格，（据本作者所知），它们首次用作MFPCMs复合材料的骨架，以增强常规PCM的有效导热性。进行了瞬态数值模拟，以比较所使用的基于TPMS的PCM复合材料与基于常规Kelvin电池的同类材料的热能存储性能。所有结构均在相同的孔隙度水平和晶胞尺寸分别为90％和7 mm的条件下进行测试。在两个边界条件（即等温和等温通量条件）下进行了仿真。还进行了稳态模拟，以评估所用MFPCM复合材料在低于所用PCM熔化温度（纯传导）的温度下的有效导热率。获得的结果强调，MFPCMs的有效导热率在很大程度上取决于电池类型及其独特的结构，而不仅取决于在使用三种TPMS结构时MFPCMs复合材料的有效导热率显着提高的电池孔隙率。在等温条件下，以开尔文（Kelvin）为基础的MFPCM为基线情况，对于Gyroid，PCM熔化时间减少了约31％，对于IWP，为PCM熔化时间减少了40.3％，对于基于基元的MFPCM，熔化时间缩短了35.3％。在等通量情况下，PCM的熔化时间不依赖于金属泡沫结构的类型。但是，通过将温度均匀性作为性能指标（由PCM域中的最大和最小温差量化），在整个熔融过程中，基于开尔文的MFPCM的差异最大（最小均一），而基于IWP的MFPCM平均比基于开尔文的MFPCM小近5K。因此，TPMS结构显示出比Kelvin电池更好的性能，更不用说比PCM单独的情况了，这使其在LHTES应用中具有潜在的应用前景。