In Silico Screening of Metal–Organic Frameworks for Adsorption-Driven Heat Pumps and Chillers

Abstract

A computational screening of 2930 experimentally synthesized metal–organic frameworks (MOFs) is carried out to find the best-performing structures for adsorption-driven cooling (AC) applications with methanol and ethanol as working fluids. The screening methodology consists of four subsequent screening steps for each adsorbate. At the end of each step, the most promising MOFs for AC application are selected for further investigation. In the first step, the structures are selected on the basis of physical properties (pore limiting diameter). In each following step, points of the adsorption isotherms of the selected structures are calculated from Monte Carlo simulations in the grand-canonical ensemble. The most promising MOFs are selected on the basis of the working capacity of the structures and the location of the adsorption step (if present), which can be related to the applicable operational conditions in AC. Because of the possibility of reversible pore condensation (first-order phase transition), the mid-density scheme is used to efficiently and accurately determine the location of the adsorption step. At the end of the screening procedure, six MOFs with high deliverable working capacities (∼0.6 mL working fluid in 1 mL structure) and diverse adsorption step locations are selected for both adsorbates from the original 2930 structures. Because the highest experimentally measured deliverable working capacity to date for MOFs with methanol is ca. 0.45 mL mL–1, the selected six structures show the potential to improve the efficiency of ACs.

Screening metal-organic frameworks for adsorption-driven osmotic heat engines via grand canonical Monte Carlo simulations and machine learning

“…The performance of adsorption-driven solution regeneration process is mainly determined by the adsorption characteristics of the adsorbents, thus selecting high-performing adsorbents is critical to improve the energy efficiency of adsorption-driven OHEs. There are various adsorbents that can be employed for adsorption, such as silica gel, activated carbons, zeolites, and metal-organic frameworks (MOFs) ( Wu et al., 2016 ; Erdős et al., 2018 ; Li et al., 2020a ). Among these adsorbents, MOFs attracted considerable attentions because of their outstanding adsorption performance due to the high volumetric surface area, structural diversity, and structural tunability ( Li et al., 2016 , 2019b ; Altintas et al., 2018 ; Kirchon et al., 2018 ).…”

Gibbs Ensemble Monte Carlo Simulation of Fluids in Confinement: Relation between the Differential and Integral Pressures

“…The widespread application of nanoporous materials in several fields, such as chromatography, membrane separation, catalysis, etc., has lead to a growing interest in the accurate description of the thermodynamic behavior of fluids confined in nanopores [1][2][3][4][5][6]. The pressure of a nanoconfined fluid is one of the most important thermodynamic properties which is needed for an accurate description of the flow rate, diffusion coefficient, and the swelling of the nanoporous material [7][8][9][10].…”

Silica-Supported Ionic Liquids for Heat-Powered Sorption Desalination

“…By matching the results in Table 2 with the silica features in Table 1, the combination of support having large pore volume with ionic liquids having high water affinity results in composites with optimal working capacities. The DA isotherm appropriately fits the experimental data and corresponds to the expression: (1) where w is the uptake [gwater gsorbent -1 ], v0 the water volumetric saturation capacity [cmwater 3 gsorbent -1 ], R the universal gas constant [kJ kmol -1 K -1 ], E the characteristic energy [kJ kmol -1 ], P the pressure [kPa], Psat the water saturation pressure [kPa] at the equilibrium temperature and n is the isotherm regression constant. The specific volume of the adsorbed phase va [cmwater 3 gwater -1 ] is estimated by the rectilinear diameters law: 50 (2)…”