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

A heat and humidity exchanger design featuring flexible, corrugated separators with flattened ridges and wide, unobstructed channels, where membrane sheets are attached to provide triangulated support and reduce pressure drop, combined with vortex-generating features to enhance flow turbulence and transfer efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If separators with closely-spaced ribs are used to support the membrane, then the membrane is supported and spacing is maintained, but the pressure drop across the apparatus increases significantly

Engineering Contradiction:

Improvemembrane supportVSAvoidpressure drop

Core Design Contradiction:

StrengthVSLoss of energy

Solution Approach 1:

The patent employs thin, flexible membrane sheets that are self-supporting or minimally supported, eliminating the need for rigid separators with closely-spaced ribs. The membranes themselves form the structural elements that define flow channels while maintaining spacing, thereby reducing pressure drop without compromising support functionality.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The invention removes the traditional separator component entirely in favor of using the membrane sheets themselves to provide both the separation function and the structural support. By extracting the separator from the system and relying on the membranes to fulfill both roles, the design eliminates the pressure drop caused by rib structures while maintaining necessary support and spacing.

Inventive Principle:

Principle #2Taking out (Extraction)

2Strength

If separators with many closely-spaced ribs are used, then the membrane is supported, but the ribs block access of the fluid to a significant portion of the membrane surface

Engineering Contradiction:

Improvemembrane supportVSAvoidmembrane surface access

Core Design Contradiction:

StrengthVSArea of stationary object

Solution Approach 1:

The membranes are designed to be self-supporting thin films that extend continuously across the flow channels without interruption by rigid separator ribs. This allows fluid to access the entire membrane surface area, maximizing the effective exchange area while the membrane's inherent flexibility provides necessary support.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The invention merges the support function and the separation function into a single integrated component - the membrane itself. Rather than having separate separators and membranes, the membrane structure is designed to provide both structural support and fluid separation, eliminating the need for additional support ribs that would block fluid access.

Inventive Principle:

Principle #5Merging (Combining)

3Strength

If flow field inserts are used to provide support and flow channels, then the membrane is supported and flow is directed, but the flow path becomes tortuous which impedes flow and increases pressure drop

Engineering Contradiction:

Improvemembrane supportVSAvoidfluid flow

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The membranes are configured to define simple, direct flow channels on both sides without the need for tortuous flow field inserts. The flexible membrane structure naturally forms smooth, unobstructed flow paths that minimize resistance and allow easy fluid flow while still providing necessary support and channel definition.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

Instead of using rigid inserts to create flow channels, the invention inverts the approach by using the flexible membranes themselves to define the channels. The membranes are shaped and positioned to create straightforward flow paths, reversing the conventional design where separate inserts dictate flow geometry.

Inventive Principle:

Principle #13The other way round (Inversion)

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 design achieves balanced pressure drops across channels, reduces energy loss, and enhances heat and humidity transfer efficiency while maintaining membrane stability and minimizing frost formation, thus improving the overall performance of energy recovery ventilators.

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

vortex-generating features to enhance flow turbulence and transfer efficiency

Methodology Applied

Scientific EffectVortex generation: Vortex Generator

Implementation Method 3

heat and humidity are transferred between the streams via the membrane

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentUS11906199B2Enthalpy exchanger

Publication Date: 2024.02.20 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.