Modular Membrane Contactor for Low-Loss Air Dehumidification
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Solution Overview
Problem
Existing three-fluid contactors with capillary membranes suffer from laminar air flow conditions, leading to low mass and heat transportation coefficients, requiring small diameter self-supporting capillaries that result in high air load losses and reduced flow rates, and are not compact or modular.
Innovation Solution
A modular three-fluids contactor with hydrophobic planar membranes, where modules are stacked and connected using spacers to facilitate turbulent air flow and reduce load leaks, utilizing thin membranes and corrosion-resistant tubes for improved efficiency and compactness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If capillary membranes with small diameter are used, then mass and heat transportation coefficients are improved, but air load losses increase and flow rate decreases
Solution Approach 1:
The contactor is divided into multiple modules, each containing a bundle of capillary membranes. This segmentation allows optimization of individual module performance while maintaining overall system efficiency, enabling the use of small diameter capillaries for high transportation coefficients without excessive load losses in the entire system.
Solution Approach 2:
The invention transitions from a single large-diameter capillary structure to multiple small-diameter capillaries arranged in bundles within modules. This dimensional reorganization maintains high surface area to volume ratio (improving mass and heat transfer) while distributing pressure drops across multiple parallel pathways, reducing overall air load losses.
2Reliability
If capillary membranes with small diameter are used, then mass and heat transportation coefficients are improved, but flow rate is reduced
Solution Approach 1:
The contactor is divided into multiple modules, each containing a bundle of capillary membranes. This segmentation allows optimization of individual module performance while maintaining overall system efficiency, enabling the use of small diameter capillaries for high transportation coefficients without excessive load losses in the entire system.
Solution Approach 2:
Multiple small-diameter capillary membranes are bundled together within each module, and multiple modules are connected in parallel. This merging approach combines the high mass and heat transfer coefficients of small capillaries with the high flow capacity of parallel configurations, achieving both improved transportation coefficients and maintained flow rate.
3Ease of manufacture
If non-modular contactor design is used, then manufacturing simplicity is maintained, but compactness and adaptability are reduced
Solution Approach 1:
The contactor is divided into identical, standardized modules that can be manufactured independently and then assembled. Each module contains a complete set of components (capillary membranes, support structures, connections), enabling simplified manufacturing of individual units while achieving compact overall design through modular stacking and parallel arrangement.
Solution Approach 2:
The modular design creates universal building blocks that can be configured in different arrangements (series, parallel, stacked) to meet various compactness requirements. Each module serves multiple functions: mass transfer, heat transfer, and structural support, reducing the overall volume needed for equivalent performance.
4Productivity
If direct contact between air and desiccant solution is used, then dehumidification efficiency is improved, but solution droplet dragging and corrosion occur
Solution Approach 1:
A hydrophobic membrane acts as an intermediary between the air stream and the desiccant solution. The membrane allows water vapor to pass from the air side to the solution side for dehumidification, while its hydrophobic properties prevent liquid solution droplets from penetrating through to the air stream, eliminating droplet dragging and corrosion while maintaining dehumidification efficiency.
Solution Approach 2:
Thin hydrophobic membranes are used as separation barriers between air and desiccant solution. These membranes provide selective permeability that enables mass transfer for dehumidification while physically preventing harmful liquid carryover, solving both efficiency and contamination problems simultaneously.
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 new contactor achieves higher mass and heat transportation coefficients, reducing air side load losses and enhancing compactness, allowing for more efficient air dehumidification and conditioning with significant energy savings and improved performance in hybrid air conditioning systems.
Implementation Method 1
a three-fluid contactor (air, desiccant liquid and thermovector fluid) with capillaries in hydrophobic membrane of separation between air and desiccant
Implementation Method 2
the energy and mass exchanges between the phases occur through a membrane, avoiding the direct contact between the phases
Implementation Method 3
The air flow within the membrane capillaries occurs in conditions of laminar motion regime, with very small mass and heat transportation coefficients on the air side
Implementation Method 4
heat exchange batteries placed in series/parallel
Implementation Method 5
The regeneration is realised by exploiting the thermal energy transfer to the condenser of the refrigeration cycle
Implementation Method 6
vapour compression refrigeration cycles to face the sensible part (air cooling)
Implementation Method 7
The regeneration is realised by exploiting the thermal energy transfer to the condenser of the refrigeration cycle
Implementation Method 8
the dehumidification of air can be realised also in a 'chemical' way, utilising solid or liquid desiccant substances
Implementation Method 9
the energy and mass exchanges between the phases occur through a membrane
Implementation Method 10
The integrated plant is provided with a thermovector fluid flow switching valve in order to implement with higher energetic efficiency also the winter heating
Data Source
Figure 1a~1b
Figure 1c~2b
Figure 2c~3a
AI summary
The present invention concerns a radical innovation of the CMC contactor ("Combined Membranes Contactor") with capillary membranes which is the subject matter of the patent application WO 2012/042553. The new contactor is composed by modules which are easily stackable and can be produced in an industrial way. The invention concerns also an integrated plant for air conditioning utilising the CMC improved according to the invention. The plant integrates a hybrid plant operating with liquid desiccants and heat exchange batteries placed in series/parallel. The integrated plant is provided with a thermovector fluid flow switching valve in order to implement with higher energetic efficiency also the winter heating besides the conditioning in the intermediate and summer seasons.