Utilization of triply periodic minimal surfaces for performance enhancement of adsorption cooling systems: Computational fluid dynamics analysis

Abstract

In this study, triply periodic minimal surface (TPMS) structures have been implemented in adsorber/desorber to improve the performance of adsorption cooling systems (ACSs). The use of metal TPMS-based structures considerably increased the effective thermal conductivity of the porous media/metal composite due to its large surface area to porous media volume. A fully-three-dimensional CFD model was constructed using Ansys Fluent and validated based on relevant previous studies. Five distinct TPMS-based structures, including Gyroid, Diamond, I-graph-wrapped package, Primitive, and Lidinoid were investigated and compared with conventional Fins-based structures under different porosities, constant adsorption times, and optimal adsorption times. The specific surface area and geometric tortuosity of the adopted structures were evaluated using GeoDict software. The results demonstrated that Lidinoid attained the cyclic specific cooling power (SCP) enhancement of 12.4 % compared to Fins-based structures under the constant adsorption time of 500 s and the consistent porosity of 0.5. Meanwhile, when operated at the optimal adsorption time for each structure, Lidinoid improved the cyclic SCP by 17.5 %, while Primitive showed 6.9 % decrease in cyclic SCP compared to Fins-based structure. The cyclic SCP of TPMS structures was better than that of Fins-based structure at medium and higher porosities of 0.5 and 0.8, respectively. However, at lower porosity of 0.2, Fins-based structures outperformed TPMS structures in cyclic SCP. In terms of daily performance, Gyroid, Diamond, and Primitive structures showed faster kinetics and more potential for ACSs applications. The results indicated that Primitive structure achieved 51.6 % increase in cooling capacity per day compared to conventional Fins-based structure. In conclusion, this study has well demonstrated that the exploitation of TPMS opens new avenues for next-generation adsorption cooling applications with superior performance.