Liquid panel assembly

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Solution Overview

Problem

Conventional liquid-to-air membrane energy exchangers face inefficiencies due to membrane bulge and pressure issues, leading to increased energy consumption and potential leaks, as well as reduced performance and higher costs, caused by the need for wide air channels and support structures that obstruct heat and moisture transfer.

Innovation Solution

The design incorporates a liquid panel assembly with a support frame and membranes, featuring counterflow passages that offset hydrostatic pressure with friction pressure loss, reducing overall pressure within the assembly and minimizing membrane bulge, while ensuring uniform liquid flow distribution across the panel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If pumping pressure is increased to force desiccant flow through the solution panel, then flow rate is improved, but membrane bulge and leaks increase

Engineering Contradiction:
Improvedesiccant flow rateVSAvoidmembrane integrity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent inverts the conventional approach by allowing desiccant to flow downward under gravity rather than pumping it upward against gravity. This reversal eliminates the need for high pumping pressure, thereby preventing membrane bulge and leaks while maintaining adequate flow rate through the solution panel.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent uses gravity as a counterweight force to balance the hydrostatic pressure of the desiccant column. By orienting the flow path vertically downward, the gravitational force counteracts the hydrostatic pressure, enabling natural flow without excessive pumping pressure that would damage membranes.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

2Reliability

If air channels are made wider to reduce membrane bulge, then membrane deformation is reduced, but heat and moisture transfer performance decreases

Engineering Contradiction:
Improvemembrane stabilityVSAvoidenergy exchange efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent creates a pressure-balanced system where friction pressure loss offsets hydrostatic pressure gain, establishing near-uniform pressure conditions throughout the liquid panel assembly. This eliminates the pressure differential that causes membrane bulge, allowing membranes to remain stable without requiring excessively wide air channels, thereby maintaining energy exchange efficiency.

Inventive Principle:
Principle #12Equipotentiality

3Reliability

If support structures are added to limit membrane bulge, then membrane deformation is reduced, but pressure drop and transfer area are increased

Engineering Contradiction:
Improvemembrane stabilityVSAvoidsupport structure requirements
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent creates a pressure-balanced system where friction pressure loss offsets hydrostatic pressure gain, establishing near-uniform pressure conditions throughout the liquid panel assembly. This eliminates the pressure differential that causes membrane bulge, allowing membranes to remain stable without requiring excessively wide air channels, thereby maintaining energy exchange efficiency.

Inventive Principle:
Principle #12Equipotentiality

4Productivity

If pumping pressure is increased to overcome static head pressure, then desiccant flow is improved, but membrane creep and degradation increase

Engineering Contradiction:
Improvedesiccant circulationVSAvoidmembrane service life
Core Design Contradiction:
ProductivityVSDuration of action of stationary object

Solution Approach 1:

The patent inverts the conventional approach by allowing desiccant to flow downward under gravity rather than pumping it upward against gravity. This reversal eliminates the need for high pumping pressure, thereby preventing membrane bulge and leaks while maintaining adequate flow rate through the solution panel.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent creates a pressure-balanced system where friction pressure loss offsets hydrostatic pressure gain, establishing near-uniform pressure conditions throughout the liquid panel assembly. This eliminates the pressure differential that causes membrane bulge, allowing membranes to remain stable without requiring excessively wide air channels, thereby maintaining energy exchange efficiency.

Inventive Principle:
Principle #12Equipotentiality

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 enhances the energy exchange efficiency by reducing pressure and preventing leaks, thereby improving the performance and longevity of the membrane energy exchanger while minimizing costs.

Implementation Method 1

the fluid circuits are configured to at least partially offset hydrostatic pressure gain with friction pressure loss of the liquid that flows within the one or more fluid circuits

Methodology Applied
Scientific EffectHydrostatic pressure: Pressure Gradient

Implementation Method 2

the fluid circuits are configured to at least partially offset hydrostatic pressure gain with friction pressure loss of the liquid that flows within the one or more fluid circuits

Methodology Applied
Scientific EffectFriction pressure loss: Friction

Implementation Method 3

a liquid is configured to flow through the one or more fluid circuits and contact interior surfaces of the at least one membrane

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 4

a liquid is configured to flow through the one or more fluid circuits and contact interior surfaces of the at least one membrane

Methodology Applied
Scientific EffectMoisture transfer: Diffusion

Data Source

PatentEP3499168B1Liquid panel assembly
Publication Date: 2021.02.17 NORTEK AIR SOLUTIONS CANADA INC
  • EP3499168B1 patent drawingFigure 1
  • EP3499168B1 patent drawingFigure 2
  • EP3499168B1 patent drawingFigure 3~4

AI summary

A liquid-to-air membrane energy exchanger configured to exchange energy between air transmitted through a plurality of air channels and the liquid transmitted through a plurality of liquid panels. The energy exchanger comprises a housing defining a cavity; a plurality of liquid panels disposed in the cavity; and a plurality of air channels disposed in the cavity. Each of the liquid panels comprises a support frame and first and second semi-permeable membranes secured to the first and second sides of the support frame. The support frame has a plurality of liquid circuits through which a liquid is configured to flow. Each of the plurality of liquid circuits comprises an inlet channel connected to an outlet channel. Each of the plurality of air channels comprises a membrane support assembly configured to support the first and second semi-permeable membranes.