Comparative analysis of MOF-303 and silica gel adsorption cooling system using cycle-resolved CFD modeling of a novel bed design

Adsorption cooling effectively utilizes low-grade heat; however, it is limited by transport at the adsorption bed level and the relatively low uptake of conventional adsorbents such as silica gel (SG). Computational fluid dynamics (CFD) serves as an essential tool for visualizing and quantifying the intricate heat and mass transport within adsorption bed design. Nonetheless, the majority of previous CFD studies have focused on single processes, employed simplified bed geometry, and concentrated solely on traditional adsorbents. In this context, a 2D, cycle-resolved CFD model has been developed to simulate the complete four-stage sequence of adsorption, preheating, desorption, and cooling for an entire adsorption bed. The model incorporates a validated user-defined function programmed in the C language. This study represents the first cycle-resolved CFD comparison of MOF-303 and SG performed within the same computational domain under identical geometry and boundary conditions. Under identical boundary conditions, MOF-303 delivers a working-capacity swing approximately 1.8 times larger than that of SG, roughly 0.09 versus 0.0498 kg.kg⁻¹. Increasing the heat transfer coefficient improved the performance up to a threshold of approximately 700 W.m⁻².K⁻¹, beyond which internal diffusion dominated. Heating water temperature is the most influential parameter: at 90 °C, MOF-303 attains a specific cooling power of approximately 241 W.kg⁻¹. Cycle time analysis indicates a trade-off: shorter half-cycles result in approximately 254 W.kg⁻¹, whereas longer half-cycles enhance regeneration and increase the uptake swing to approximately 0.142 kg.kg⁻¹ for MOF-303. The developed cycle resolved model clarifies when and why MOF-303 outperforms SG and identifies the operating windows for compact, low-grade heat-driven ACS.