Enthalpy exchanger

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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 loss, while also restricting access to the membrane surface.

Innovation Solution

The design incorporates a corrugated or zig-zag separator with thin, flexible membrane sheets attached to provide triangulated support, creating wide unobstructed channels for fluid flow and reducing pressure drops by minimizing membrane deflection and surface area drag, along with optional vortex-generating features to enhance turbulence and heat transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If separators with closely-spaced ribs are used to support the membrane, then membrane stability is improved, but pressure drop increases and fluid flow is restricted

Engineering Contradiction:

Improvemembrane stabilityVSAvoidpressure drop

Core Design Contradiction:

Stability of the object's compositionVSLoss of energy

Solution Approach 1:

The separator is divided into multiple ribs spaced at specific intervals, creating multiple support points that stabilize the membrane while maintaining open flow channels between the ribs. This segmentation allows the separator to provide structural support without completely blocking fluid flow paths.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The separator structure is designed with different properties in different locations: the ribs provide localized support where membrane stability is needed, while the spaces between ribs maintain open channels for fluid flow. This local differentiation resolves the contradiction between support and flow.

Inventive Principle:

Principle #3Local quality

2Strength

If ribs of significant thickness are used to support the membrane, then membrane support is improved, but fluid flow access to membrane surface is restricted

Engineering Contradiction:

Improvemembrane supportVSAvoidfluid flow access

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The ribs are designed with a curved or arched cross-section rather than flat surfaces. This curvature allows the ribs to provide structural support while presenting a streamlined shape to the fluid flow, reducing flow resistance and improving access to the membrane surface compared to flat, thick ribs.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The separator ribs are designed with sufficient flexibility to allow fluid flow close to their surfaces without complete blockage, while still providing adequate support for the membrane. The ribs act as flexible support structures rather than rigid barriers.

Inventive Principle:

Principle #30Flexible shells and thin films

3Stability of the object's composition

If flow field inserts are used to provide support and flow channels, then membrane support is improved, but flow path becomes tortuous increasing pressure drop

Engineering Contradiction:

Improvemembrane supportVSAvoidpressure drop

Core Design Contradiction:

Stability of the object's compositionVSLoss of energy

Solution Approach 1:

Instead of using complex flow field inserts that create tortuous paths, the invention inverts the approach by using simple, straight ribs that create parallel flow channels. This inverted simplicity reduces flow path length and resistance while maintaining membrane support.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The rib spacing and dimensions are optimized to create flow channels with appropriate hydraulic diameter and length, changing the flow path parameters from tortuous and long to relatively straight and short, thereby reducing pressure drop while maintaining support functionality.

Inventive Principle:

Principle #35Parameter changes

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 achieves balanced pressure drops across channels, reduces energy loss, and enhances heat and humidity transfer efficiency while maintaining membrane stability and flexibility.

Implementation Method 1

first and second thin water-vapor-permeable membrane sheets attached to the projections

Methodology Applied

Scientific EffectWater vapor permeation: Permeation

Implementation Method 2

The separators support the membrane, and reduce or prevent deflection of the membrane into the channels 5

Methodology Applied

Scientific EffectTriangulated support:

Implementation Method 3

optional vortex-generating features to enhance turbulence and heat transfer

Methodology Applied

Scientific EffectVortex generation: Vortex Generator

Implementation Method 4

heat and humidity are transferred between the streams via the membrane

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentUS10845068B2Enthalpy exchanger

Publication Date: 2020.11.24 CORE ENERGY RECOVERY SOLUTIONS INC

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.