Numerical and experimental investigation of ultra-compact triply periodic minimal surface heat exchangers with high efficiency

•Introduces ultra-compact TPMS heat exchangers with record efficiency up to 16.5 W/(cm³·K).•Successfully 3D prints complex TPMS structures, enabling new design possibilities.•Develops experimental correlations in heat transfer and pressure drop.•Achieves up to 200 % improvement in PEC over traditional heat exchangers. With the rapid growth in energy efficiency demands, compact heat exchangers are gaining increasing attention. This study proposes a novel heat exchanger design based on Triply Periodic Minimal Surface (TPMS) structures, leveraging their unique three-dimensional porous structure to enhance heat transfer efficiency and compactness. This study employs computational fluid dynamics (CFD) simulations to analyze the thermal performance of three TPMS structures (Gyroid, Diamond, and Fischer-Koch S) heat exchangers. Two optimized structures are selected for additive manufacturing based on the simulation results. The manufactured heat exchangers are inspected using CT scans, and a dual-fluid experimental performance testing system is constructed to assess the potential application of the two heat exchangers in thermal management systems. Using the least squares method, correlations for heat transfer and pressure drop are separately fitted for the two TPMS heat exchangers. Dimensionless Performance Evaluation Coefficient (PEC) values are utilized to analyze the comprehensive performance of the two TPMS heat exchangers. The heat transfer rate per unit volume has increased by approximately 50 times compared to traditional heat exchangers reported in the literature, which reaches an impressive 717.7 W/cm3 and 16.5 W/(cm³·K). This study will provide design guidance for enhancing the compactness and efficiency of TPMS heat exchangers.