Membrane Plate Exchanger Channels for Low-Gradient Humidity Transfer
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Solution Overview
Problem
Conventional gas-gas mass exchangers are ineffective in exchanging temperature and humidity when temperature gradients between air flows are low, such as in building air conditioning systems, as they rely on large gradients for efficient operation.
Innovation Solution
A gas-gas mass exchanger with a newly designed plate unit featuring a folded plastic structure and a selectively permeable membrane, where the channels are shaped to induce turbulence in the gas flow, ensuring effective contact between the gas and the membrane, and the plate units are stacked with alternating channel routing to facilitate efficient mass transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional mass exchangers are used with large temperature gradients, then effective temperature and mass exchange can be achieved, but they work ineffectively with low gradients occurring in building air conditioning
Solution Approach 1:
The patent changes the flow regime parameter from laminar to turbulent flow by introducing turbulence-generating means in the channels. This allows effective mass and heat transfer even when temperature gradients are small, as turbulence enhances mixing and reduces boundary layer resistance. The turbulence intensity is controlled by adjusting flow velocity and channel geometry to optimize transfer efficiency across different gradient conditions.
Solution Approach 2:
The patent employs a selectively permeable membrane with specific porosity characteristics that allows water vapor to pass through while blocking liquid water and air. This porous membrane structure enables effective mass transfer under low temperature gradients by providing a large surface area for diffusion and phase change, overcoming the limitation of conventional exchangers that rely on large temperature differences.
2Productivity
If a selectively permeable membrane is stretched over a folded plate with channel structure, then effective contact between gas and membrane is achieved through induced turbulence, but the plate structure must provide sufficient support
Solution Approach 1:
The plate is divided into multiple channels separated by partition walls, with turbulence-generating means positioned at specific locations within each channel. This segmentation allows turbulence to be induced locally without requiring excessive overall structural strength. Each segment can be independently optimized for flow characteristics while the entire structure maintains sufficient support for the membrane.
Solution Approach 2:
The turbulence-generating means may include curved or angled surfaces that redirect flow to create rotational and turbulent motion. These curved geometries induce turbulence effectively while distributing mechanical stresses evenly across the plate structure, maintaining strength and support capability without requiring excessive material or thickness.
3Productivity
If channels are shaped to induce turbulence with cross-flows, then standing boundary layers are prevented and contact between gas and membrane is improved, but the channel design becomes more complex
Solution Approach 1:
The channel geometry is designed to dynamically induce turbulence through flow direction changes rather than static complex structures. The channels may include gradual bends, expansions, or contraction sections that naturally generate turbulent flow patterns as the gas moves through, achieving effective mixing and contact without requiring intricate static geometries.
Solution Approach 2:
Turbulence-generating means are introduced as intermediary elements within the channels, such as ribs, protrusions, or angled surfaces that mediate between the simple channel structure and the requirement for turbulent flow. These intermediaries create the necessary flow disturbances and cross-flows to prevent boundary layer formation while adding minimal geometric complexity to the overall channel design.
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
The solution enables effective temperature and humidity equalization even with low temperature gradients, significantly increasing the efficiency of mass transfer between air flows, making it suitable for applications like air dehumidification and humidification in buildings.
Implementation Method 1
a selectively permeable membrane, which is permeable to certain substances and impermeable to other substances
Implementation Method 2
The channels are shaped in such a way that a fluid flowing through, for example a gas, experiences slight turbulence at its boundary layers, so that almost no standing boundary layers are formed on the membrane
Implementation Method 3
Heat and mass exchangers, in particular for streams of gaseous media, are known from the prior art. In this case, two differently tempered and/or moist streams are guided past one another, so that an exchange of temperature and/or mass can take place between these streams
Data Source
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AI summary
The invention relates to a plate unit (10) for a gas-to-gas matter exchanger, at least comprising at least one plate (11) having at least one channel structure (12), which forms at least one channel (13) for a fluid, wherein the at least one plate (11) is made of a plastic, and at least one selectively matter-permeable membrane (16), which is stretched out on the at least one plate (11). The invention further relates to a gas-to-gas matter exchanger, at least comprising a matter exchanger package (20) comprising a plurality of matter exchanger plate units, which are arranged in parallel and through the channels (13) of which a first fluid and a second fluid flow in alternation, wherein the matter exchanger plate units are designed as plate units (10) according to the invention, and a building ventilation system designed as a gas-to-gas matter exchanger according to the invention.