Compact membrane-based absorption heat pump
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Solution Overview
Problem
Existing absorption heat pumps face challenges in compactness, energy efficiency, and cost-effectiveness, limiting their wider application in HVAC systems, particularly due to large size and high energy consumption, as well as the need to utilize low-grade thermal energy effectively.
Innovation Solution
The development of a membrane-based absorption heat pump system utilizing microchannel modules with a porous membrane that separates solution and refrigerant flows, enabling high compactness and efficient heat/mass transfer, and allowing direct diffusion of water molecules to reduce driving temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional absorption heat pump systems are used, then heating and cooling functions are provided, but the system size is large and space requirements are high
Solution Approach 1:
The patent transitions from conventional macro-scale heat exchangers to microchannel heat exchangers, utilizing the micro-scale dimension to achieve vastly increased surface area to volume ratio. This dimensional change enables compact system size while maintaining or improving heat transfer efficiency, as the microchannels provide extensive heat transfer surface area within a minimal volume
Solution Approach 2:
The patent employs porous membranes as separating structures in the heat exchanger system. These porous materials provide large specific surface area for heat and mass transfer while occupying minimal volume. The porous structure enables efficient molecular diffusion and heat exchange between the absorbent solution and refrigerant vapor, achieving high heat transfer efficiency in a compact configuration
2Ease of manufacture
If conventional absorption heat pump systems are used, then heating and cooling functions are provided, but the system cost is high
Solution Approach 1:
The patent combines multiple functions into integrated membrane-based modules that serve as both heat exchangers and mass transfer separators. The generator, condenser, evaporator, and absorber functions are merged into compact membrane modules, reducing the number of separate components and simplifying manufacturing. This integration lowers system cost while the efficient heat and mass transfer in the merged structures maintains or improves energy efficiency
Solution Approach 2:
The patent changes the operating parameters by utilizing low-grade thermal energy at reduced temperatures through the membrane-based system. The porous membrane structure enables efficient mass transfer at lower temperature differences, allowing the system to operate effectively with low-grade heat sources. This parameter change improves energy efficiency by utilizing previously unusable thermal energy while simplifying system requirements and reducing cost
3Temperature
If conventional absorption heat pump systems are used, then heating and cooling functions are provided, but the driving temperature is high
Solution Approach 1:
The porous membranes enable efficient molecular diffusion and mass transfer at lower temperature differences compared to conventional systems. The large specific surface area of the porous structure provides numerous pathways for mass and heat transfer, reducing the required driving temperature. This allows the system to operate effectively with low-grade thermal energy while maintaining high energy efficiency through the enhanced transfer efficiency of the porous medium
Solution Approach 2:
The patent replaces conventional mechanical heat transfer mechanisms with diffusion-based mass transfer through porous membranes. Instead of relying on high temperature differences to drive heat transfer, the system uses concentration gradients and molecular diffusion through the porous membrane structure. This substitution enables operation at lower driving temperatures while maintaining or improving energy efficiency through the selective and efficient mass transfer properties of the porous medium
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
This approach results in a compact, efficient, and cost-effective low-carbon HVAC solution that can utilize low-grade thermal energy, enhancing energy efficiency and reducing space requirements while maintaining high performance.
Implementation Method 1
Direct diffusion of water molecules through the membrane makes it possible to lower the required driving temperatures
Implementation Method 2
A porous membrane is positioned between the refrigerant channel and the solution channel; the porous membrane permits flow of vapor molecules therethrough while restricting flow of absorbent molecules
Implementation Method 3
The microchannel membrane-based modules use membranes having a large specific surface area and integrated solution/refrigerant flows, which enables formation of a highly compact heat pump exhibiting strong heat/mass transfer
Implementation Method 4
an absorption heat pump (liquid sorption) and an adsorption heat pump (solid sorption)
Data Source
AI summary
The present invention provides a heat pump that includes an absorber/evaporator module having a solution channel and a refrigerant channel along with first and second liquid channels. A porous membrane is positioned between the refrigerant channel and the solution channel; the porous membrane permits flow of vapor molecules therethrough while restricting flow of absorbent molecules. A membrane-based generator/condenser module with a similar structure is in fluid communication with the absorber/evaporator module. The membrane-based modules offer a large specific surface area with integrated solution/refrigerant flows, which enables formation of a highly compact heat pump exhibiting strong heat/mass transfer.