Liquid-to-air membrane energy exchanger
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Solution Overview
Problem
Conventional liquid-to-air membrane energy exchangers (LAMEEs) face inefficiencies due to mal-distributed fluid flows, which lead to sub-optimal performance in energy transfer, particularly in HVAC systems, as existing designs fail to account for the complexities of fluid flow dynamics and geometric variations, resulting in uneven heat and mass transfer rates.
Innovation Solution
The design incorporates a housing with panels forming desiccant and air channels, where the desiccant channels are configured for counter-flow or cross-flow directions to facilitate heat and water vapor transfer, with specific geometric and operational parameters such as aspect ratios, flow channel dimensions, and membrane properties optimized to ensure uniform flow distribution and enhanced turbulence, thereby improving energy exchange efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional LAMEE designs are used, then the device complexity is reduced, but the energy transfer effectiveness deteriorates due to mal-distributed fluid flows
Solution Approach 1:
The patent applies local quality by varying the flow channel dimensions (width, height, length) of different panels within the LAMEE assembly. Each panel can have customized geometric parameters to compensate for position-dependent flow maldistribution, ensuring uniform flow distribution across all panels while maintaining optimized energy transfer effectiveness.
2Productivity
If uniform flow distribution is achieved through optimized geometric parameters, then the energy transfer effectiveness is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent employs parameter changes by systematically varying the geometric parameters (width, height, length) of flow channels across different panels. This allows optimization of flow distribution and energy transfer effectiveness through parameter tuning rather than relying solely on tight manufacturing tolerances, thereby reducing the stringency of manufacturing precision requirements.
3Productivity
If the aspect ratio of energy exchange areas is optimized, then the turbulence is enhanced and energy transfer is improved, but the pressure drop increases
Solution Approach 1:
The patent applies local quality by optimizing the aspect ratio of energy exchange areas differently for various panels based on their position in the assembly. This localized optimization enhances turbulence and energy transfer effectiveness in regions where it is most beneficial while managing pressure drop through position-dependent geometric parameters.
Solution Approach 2:
The patent employs dynamics by making the flow channel geometric parameters adjustable and optimizable rather than fixed. This allows the system to adapt the aspect ratios and dimensions to balance turbulence enhancement for energy transfer against pressure drop considerations, achieving optimal performance through dynamic parameter selection.
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 leads to increased energy transfer effectiveness and reduced pressure drops, allowing LAMEEs to meet stringent performance standards, such as ASHRAE standards, by optimizing flow distribution and turbulence, resulting in improved HVAC system performance.
Implementation Method 1
The panels have a semi-permeable membrane forming an energy exchange area of the panel. The panels form desiccant channels and air channels that are separated by the semi-permeable membranes to facilitate contact between an air stream flowing through the air channels and desiccant flowing through the desiccant channels within the energy exchange areas of the panels
Implementation Method 2
The panels have a semi-permeable membrane forming an energy exchange area of the panel. The panels form desiccant channels and air channels that are separated by the semi-permeable membranes to facilitate contact between an air stream flowing through the air channels and desiccant flowing through the desiccant channels
Implementation Method 3
The desiccant channels are configured to channel the desiccant from the desiccant inlet to the desiccant outlet in at least one of a counter-flow or cross-flow direction with respect to the direction of the air stream to facilitate heat and water vapor transfer through the semi-permeable membranes
Implementation Method 4
The desiccant channels are configured to channel the desiccant from the desiccant inlet to the desiccant outlet in at least one of a counter-flow or cross-flow direction with respect to the direction of the air stream to facilitate heat and water vapor transfer through the semi-permeable membranes
Data Source
AI summary
An energy exchanger is provided. The exchanger includes a housing having a front and a back. A plurality of panels forming desiccant channels extend from the front to the back of the housing. Air channels are formed between adjacent panels. The air channels are configured to direct an air stream in a direction from the front of the housing to the back of the housing. A desiccant inlet is provided in flow communication with the desiccant channels. A desiccant outlet is provided in flow communication with the desiccant channels. The desiccant channels are configured to channel desiccant from the desiccant inlet to the desiccant outlet in at least one of a counter-flow or cross-flow direction with respect to the direction of the air stream.