Experimental analysis of a gyroid-based heat and mass exchanger for Maisotsenko cooling cycle

The increasing global demand for space cooling, driven primarily by climate change, highlights the need for sustainable alternatives to vapor-compression systems and dew-point evaporative cooling is emerging as a promising solution in this context, as it enables efficient air temperature reduction to levels lower than those achievable with conventional evaporative systems. This work presents a first experimental investigation of an innovative cross-flow heat and mass exchanger (HMX) based on gyroid triply periodic minimal surfaces applied to the Maisotsenko cycle, marking a shift from traditional parallel-plate paradigms by introducing a fundamentally different 3D heat and mass transfer topology that leverages complex geometric structures to enhance thermal performance. The device, manufactured in polylactic acid (PLA) through material extrusion, is characterized by a hydraulic diameter of 9.16 mm and has been tested at inlet air temperatures of 30 °C and 35 °C, with corresponding relative humidities of 43% and 32%, air velocities from 2.3 to 4.1 m/s and recirculation rates between 0.2 and 0.7. The HMX achieved a maximum temperature drop of 6.1 °C and a volumetric cooling capacity of 55.6 kW/m 3 , exceeding the typical values reported in literature for standard geometries. The maximum coefficient of performance (COP) of 9.1 was obtained at 35 °C, with r ≈ 0.2 and air velocity of ≈ 2.5 m/s. The results indicate that the turbulence-promoting nature of the gyroid geometry shifts the optimal operating range toward significantly lower air velocities (<2.5 m/s) compared to conventional planar HMX configurations, while higher velocities ( ≈ 4 m/s) lead to a rapid degradation of COP. Although the wet-bulb effectiveness was limited to slightly above 50% by both the conductive thermal resistance of PLA and the relatively short length of the HMX, the gyroid structure sustained intense mass transfer, maintaining outlet relative humidity above 83%, indicating an oversized wet channel and motivating geometrically asymmetric designs with longer dry channels and wider wet channels. • First experimental assessment of a gyroid-based TPMS heat exchanger for DPEC • Volumetric cooling capacity of 55.6 kW/m 3 exceeds standard HMX designs. • Maximum COP of 9.1 achieved at 35 °C with a 2.5 m/s characteristic velocity. • Outlet relative humidity above 83% confirms strong evaporation effectiveness. • Peak temperature drop of 6.1 °C was recorded at an inlet temperature of 35 °C.