Cooling/heating method and device based on metal-organic frameworks and induced by pressure modifications
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current cooling technologies, particularly those using refrigerant gases, face inefficiencies and environmental concerns, with high greenhouse gas emissions and the need for materials that can exhibit large thermal changes at ambient temperatures and low pressures, while avoiding water usage and maintaining effectiveness in refrigeration and HVAC applications.
Innovation Solution
The use of porous organic-inorganic hybrid compounds, specifically Metal-Organic Frameworks (MOFs) with breathing transitions, which undergo pore opening/closing and gas adsorption/desorption sensitive to pressure changes, allowing for efficient cooling and heating within a temperature range of -20°C to 60°C and pressures between 10^-6 MPa and 50 MPa, achieving isothermal entropy changes greater than 100 J K^-1 kg^-1.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If CO2 cooling systems are used to achieve low GWP and environmental friendliness, then greenhouse gas emissions are reduced, but working pressures must be increased to 45-70 bar for ambient temperatures and 100-150 bar for temperatures above 30°C
Solution Approach 1:
The patent employs barocaloric materials that undergo solid-solid phase transitions under pressure changes to achieve cooling effects. This allows the system to operate at much lower pressures (below 300 bar, preferably 1-70 bar) compared to CO2 systems while maintaining environmental friendliness and avoiding the high pressure requirements of conventional refrigeration cycles
Solution Approach 2:
The invention changes the fundamental operating parameter from high-pressure gas compression (CO2 systems) to moderate-pressure solid-state phase transitions. By utilizing materials with specific phase transition characteristics that occur at lower pressures, the system achieves both environmental benefits and reduced pressure requirements simultaneously
2Power
If barocaloric compounds are used to achieve solid-state cooling with large thermal changes, then cooling capacity is improved, but working pressures must be increased to 1000-2500 bar
Solution Approach 1:
The patent selects specific barocaloric materials with locally optimized properties - choosing materials whose phase transitions occur at the desired lower pressure range (1-70 bar) while maintaining sufficient thermal change magnitude for practical cooling applications. This involves selecting materials with specific crystal structures and transition characteristics that match the target operating conditions
Solution Approach 2:
The invention changes the pressure parameter range from extreme high pressure (1000-2500 bar) to moderate pressure (1-70 bar) by selecting materials with appropriate phase transition characteristics. This parameter optimization allows the system to achieve both adequate cooling capacity and reduced pressure requirements
3Stress or pressure
If non-porous organic-inorganic hybrid compounds are used to achieve low working pressures (1-70 bar), then pressure requirements are reduced, but thermal changes and working temperature range are relatively small
Solution Approach 1:
The patent employs composite barocaloric materials combining organic and inorganic components with synergistic properties. The composite structure enables both low working pressure operation (1-70 bar) and enhanced thermal changes, overcoming the limitations of non-porous hybrid compounds by incorporating porous structures or interfaces that amplify the barocaloric effect
Solution Approach 2:
The invention optimizes material composition and structure to simultaneously achieve low pressure requirements and large thermal changes. By adjusting the composite material's chemical composition, pore structure, and phase transition characteristics, the system expands both the working temperature range and the magnitude of thermal changes while maintaining moderate pressure operation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
MOFs provide a more efficient and environmentally friendly cooling and heating solution by achieving significant thermal changes with reduced pressure requirements, eliminating water usage, and operating effectively across a broad temperature range, thus addressing the limitations of existing technologies.
Implementation Method 1
presenting a first-order phase transition where opening/closing of the pores of the materials occurs, combined with adsorption/desorption of gases that is very sensitive to changes in pressure of a pressurising gas (effect known as breathing transition, gate opening transition or pore opening transition of MOFs)
Implementation Method 2
combined with adsorption/desorption of gases that is very sensitive to changes in pressure of a pressurising gas
Implementation Method 3
means for applying/removing pressure by means of a pressurising gas and vacuum pump
Implementation Method 4
removal of pressure is carried out by means of releasing the pressurising gas through a depressurisation valve, by means of applying a vacuum through a vacuum pump
Data Source
AI summary
A cooling/heating method including the application and removal of a pressurising gas on a hybrid organic-inorganic porous material (MOF) whereby a breathing transition is produced. In this transition, a change in volume in the structure of the compound occurs when its pores open/close, together with adsorption/desorption of a gas after applying and removing a pressurising gas on the compound; and breathing which occurs at temperatures close to ambient temperature (from −20° C. to 60° C.) and at low pressures (from 10−5 bar up to 50 bar) and with great isothermal entropy changes (>100 J K−1 kg−1). A cooling/heating device comprising the hybrid materials defined above.