Performance Prediction of Metal-Organic Frameworks (MOFs) based Desiccants for Adsorption Air-conditioning System

Metal-organic frameworks (MOFs) are a new class of porous crystalline materials with multiple and tuneable structures, which possess varieties of combinations from different metal clusters and organic ligands. Most MOF-based desiccants exhibit exceptional properties such as remarkable water vapour uptake capacity and gentle regeneration conditions, which make them very competitive for the adsorption air-conditioning system in comparison with conventional desiccants, for example, zeolite etc. The paper aims at investigating the performance of MOF-based adsorption system in comparison with the conventional zeolitebased system. The isotherms of MOF-based desiccants unºCder different temperature have been investigated to estimate the equilibrium concentration of the adsorbed vapour. The experimental results indicate that there is more than 0.4 g/g of mass difference between 20 and 50 ºC at 2000 Pa of water vapour pressure, which means the MOF-based adsorption cooling system can be powered by using low-grade energy around 50-70 ºC temperature range. A mathematical model has been developed based on the general adsorption dynamics for a thin desiccant layer. Numerical simulations have been carried out to predict the change of adsorption dynamics under different vapour pressure. The results have shown that the MOF-based adsorption air-conditioning system powered by the low-grade energy exhibit higher operation performance in comparison with the traditional zeolite-based system.