Effects of functionalization on the performance of metal-organic frameworks for adsorption-driven heat pumps by molecular simulations

Abstract

Abstract Metal-organic frameworks (MOFs) are promising adsorbents for adsorption-driven heat pumps (AHPs) due to their outstanding adsorption performance. However, the role of functionality in tuning the AHP performance has not been elucidated. In this work, the ethanol adsorption behaviors and AHP performance of Zr-based MOFs in three topologies (i.e. csq, ftw and scu) functionalized by –NH2 and –CF3 exhibiting different affinities towards ethanol working fluid were investigated by grand canonical Monte Carlo simulations (GCMC). It was revealed that functionalization not only affected the adsorption capacity but also shifted the steps of isotherms to the low pressure upon functionalization by –NH2. scu-MOFs exhibited the higher coefficient of performance for cooling (COPC) than csq-MOFs and ftw-MOFs. Moreover, functionalization reduced the COPC of ftw-MOFs and scu-MOFs due to the lower working capacity resulting from the reduced pore volumes. On the contrary, the COPC of csq-MOFs can be improved upon functionalization by –NH2.