Enthalpy Exchanger with Corrugated Separators to Reduce Pressure Drop
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Solution Overview
Problem
Existing heat and humidity exchangers face significant pressure drops due to the use of separators with closely-spaced ribs or flow field inserts, which impede fluid flow and increase energy losses, while also restricting access to the membrane surface.
Innovation Solution
The design incorporates a heat and humidity exchanger with corrugated or zig-zag separators that provide triangulated support to the membranes, along with thin, flexible membrane sheets attached to the separators, creating wide unobstructed channels for fluid flow and reducing pressure drops by minimizing membrane deflection and friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If separators with closely-spaced ribs are used to support the membrane, then membrane support and spacing are improved, but pressure drop increases and fluid flow is impeded
Solution Approach 1:
The separator transitions from a planar structure with closely-spaced ribs to a three-dimensional corrugated structure with peaks and valleys. This dimensional change allows the membrane to be supported at elevated peaks while maintaining wide, unobstructed flow channels in the valleys, thereby supporting the membrane without impeding fluid flow or increasing pressure drop
Solution Approach 2:
The separator surface is segmented into discrete support peaks rather than continuous ribs. This segmentation provides sufficient membrane support at each peak while leaving the intervening valleys open for fluid flow, reducing the overall resistance to flow compared to continuous closely-spaced ribs
2Strength
If flow field inserts are used to provide support and flow channels, then membrane support is improved, but fluid flow access to membrane surface is restricted
Solution Approach 1:
The separator is elevated from a flat plane to a corrugated three-dimensional structure with peaks and valleys. The membrane is supported at the peaks while the valleys provide wide, unobstructed access channels for fluid to reach the membrane surface, eliminating the flow restriction caused by planar flow field inserts
3Productivity
If membrane sheets are made thin and flexible for permeability, then heat and humidity transfer efficiency is improved, but membrane deflection increases
Solution Approach 1:
The corrugated separator creates a three-dimensional support structure with peaks that elevate and stabilize the membrane sheets. This allows the membrane to remain thin and flexible for efficient heat and humidity transfer while the peaks prevent excessive deflection into the flow channels, maintaining structural stability
Solution Approach 2:
The corrugated separator acts as an intermediary support structure between the thin membrane sheets and the flow channels. It provides mechanical support to prevent membrane deflection while maintaining the permeability characteristics of the thin membrane, mediating between the conflicting requirements of flexibility and stability
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 configuration maintains efficient heat and humidity transfer while minimizing pressure drops across the exchanger, ensuring effective energy recovery with reduced flow resistance and increased membrane surface accessibility.
Implementation Method 1
first and second thin water-vapor-permeable membrane sheets attached to the projections
Data Source
AI summary
A heat and humidity exchanger comprises panels made up of membrane sheets attached on either side of a separator. Channels extend across each panel between the separator and the membrane sheets. The panels are much stiffer than the membrane sheets. Panels are stacked in a spaced apart relationship to provide an ERV core. Spacing between adjacent panels may be smaller than a thickness of the panels.