An experimental investigation of indirect evaporative cooling in gyroid-based heat exchangers

This study explores the performance of crossflow indirect evaporative coolers (IECs) based on gyroid geometries and fabricated using PLA through fused filament fabrication. Different gyroid cell sizes were tested in both dry and wet conditions. Dry tests demonstrate high heat transfer performance, with a maximum convective heat transfer coefficient of approximately 170 W/(m2K) in turbulent flow. Under wet conditions, the gyroid-based IECs achieved a volumetric cooling capacity three times higher than traditional crossflow heat exchangers, while the wet-bulb efficiency reached up to 90 %, highlighting the benefits of high surface-to-volume ratios for enhanced evaporation. Although the coefficient of performance (COP) of gyroid-based IEC peaked between 57.9 and 84.7 in high temperature and low humidity conditions, conventional IEC reach values 2-5 times higher under milder operating conditions, typical of temperate climates with moderate humidity, due to lower pressure drop. In any case, the COP remains significantly superior to that of vapor compression cooling systems. A key limitation of this study is the scale of the tested prototypes, which may not fully capture performance and distribution challenges in larger systems. However, although the results are not directly scalable, they provide a consistent comparison of the performance of different geometries suggesting that gyroid-based IECs are particularly suitable for cooling applications requiring compactness and high-power density.