Manipulating Pore Topology and Functionality to Promote Fluorocarbon-Based Adsorption Cooling.
Dushyant Barpaga1, Jian Zheng2,3, B Peter McGrail1
1Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, United States.
Accounts of Chemical Research
|December 27, 2021
Summary
This study enhances adsorption cooling by engineering metal-organic frameworks (MOFs) and covalent organic polymers (COPs) to improve sorbent/refrigerant interactions. This molecular-level design boosts working capacity for more efficient, sustainable cooling systems.
Area of Science:
- Materials Science
- Chemical Engineering
- Thermodynamics
Background:
- Growing global demand for cooling necessitates alternatives to electricity-intensive refrigeration.
- Adsorption cooling offers an eco-friendly approach, utilizing waste heat for refrigerant gas adsorption/desorption.
- Current limitations in sorbent/refrigerant pairs hinder the efficiency and applicability of adsorption cooling systems.
Purpose of the Study:
- To enhance sorption cooling performance by optimizing sorbent/refrigerant pairs at a molecular level.
- To investigate the host-guest chemistry and pore topology effects in metal-organic frameworks (MOFs) and covalent organic polymers (COPs) for improved adsorption.
- To engineer novel MOF/COP materials with enhanced working capacities for hydrofluorocarbon refrigerants.
Main Methods:
- Synthesizing MOFs and COPs with tailored porosity (pore size, volume) using elongated linkers and stereochemistry control.
- Modifying sorbate/sorbent interactions via functional moieties or unsaturated metal centers.
- Utilizing in situ experimental techniques including synchrotron X-ray diffraction, X-ray absorption spectroscopy, FTIR, and calorimetry.
- Employing computational methods like density functional theory (DFT) and grand canonical Monte Carlo (GCMC) simulations to corroborate experimental findings.
Main Results:
- Demonstrated strategies for engineering framework porosity and manipulating sorbate/sorbent interactions to enhance adsorption capacity.
- Identified the crucial role of framework pore topology and defective sites in adsorption isotherm behavior.
- Established a molecular-level understanding of refrigerant interactions with MOF/COP materials.
- Achieved improved working capacities in targeted sorbent/refrigerant pairs.
Conclusions:
- Engineered MOFs and COPs show significant potential for advancing adsorption cooling technology.
- Molecular-level design and understanding of sorbent-refrigerant interactions are key to enhancing cooling system efficiency.
- This research paves the way for developing highly effective working pairs for sustainable sorption-based cooling.
