Membrane Liquid Panel Flow Layout for Low-Pressure Energy Exchange

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Solution Overview

Problem

Conventional liquid-to-air membrane energy exchangers face issues with membrane bulge and pressure drop due to high hydrostatic pressure and friction, leading to reduced performance, increased costs, and potential leaks, as well as inefficient heat and moisture transfer.

Innovation Solution

The liquid panel assembly features a support frame with fluid circuits that offset hydrostatic pressure gain with friction pressure loss, using counterflow passages and carefully designed channel shapes and orientations to reduce pressure within the assembly, thereby minimizing membrane bulge and promoting uniform liquid flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high pumping pressure is used to force desiccant flow through the solution panel, then desiccant flow is maintained, but membrane bulge and potential leaks increase

Engineering Contradiction:
Improvedesiccant flowVSAvoidmembrane 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 reverses the pressure dynamics, eliminating the need for high pumping pressure while maintaining desiccant flow through the solution panel, thereby protecting membrane integrity from excessive pressure-induced bulge and leaks

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 solution panel vertically and allowing downward flow, the gravitational force counteracts the hydrostatic pressure buildup, reducing net pressure on membranes while maintaining continuous desiccant circulation

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

2Reliability

If wide air channels are used to accommodate membrane bulge, then membrane restriction is reduced, but heat and moisture transfer performance decreases

Engineering Contradiction:
Improveair flowVSAvoidheat and moisture transfer
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent uses gravity-induced downward desiccant flow to counterbalance the outward bulge force of membranes into air channels. This counterweight effect keeps membranes relatively flat and maintains narrow air channel dimensions, ensuring high heat and moisture transfer performance without excessive air flow restriction

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

Solution Approach 2:

The patent changes the orientation parameter of the solution panel from horizontal to vertical, which fundamentally alters the pressure distribution and membrane behavior. This parameter change allows membranes to remain flat under gravity-driven flow, maintaining optimal air channel geometry for heat and moisture transfer while accommodating membrane movement

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If uniform desiccant distribution is enforced through high pumping pressure, then flow uniformity is improved, but energy consumption and membrane stress increase

Engineering Contradiction:
Improvedesiccant distribution uniformityVSAvoidpumping energy
Core Design Contradiction:
Stability of the object's compositionVSUse of energy by stationary object

Solution Approach 1:

The patent inverts the flow direction to utilize gravity for downward desiccant movement, eliminating the need for energy-intensive pumping. This inversion naturally promotes uniform desiccant distribution through the vertically-oriented solution panel while dramatically reducing energy consumption and membrane stress from pumping pressure

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

Solution Approach 2:

The patent enables the desiccant flow system to serve itself by using gravity as the driving force rather than external pumps. The vertical orientation and downward flow allow the system to maintain uniform desiccant distribution through natural gravitational forces, eliminating the need for auxiliary pumping energy and reducing membrane stress

Inventive Principle:
Principle #25Self-service

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 reduces total pressure within the liquid panel assembly, minimizing the risk of leaks and membrane creep, while enhancing the efficiency of heat and moisture transfer by ensuring uniform flow distribution and reducing the need for excessive pumping pressure.

Implementation Method 1

the one or more 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 to reduce pressure within the liquid panel assembly

Methodology Applied
Scientific EffectHydrostatic pressure: Pressure Gradient

Implementation Method 2

the one or more 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

enhancing the efficiency of heat and moisture transfer by ensuring uniform flow distribution

Methodology Applied
Scientific EffectMoisture transfer: Diffusion

Data Source

PatentEP2893283B1Liquid panel assembly
Publication Date: 2018.12.12 NORTEK AIR SOLUTIONS CANADA INC
  • EP2893283B1 patent drawingFigure 1
  • EP2893283B1 patent drawingFigure 2
  • EP2893283B1 patent drawingFigure 3~4

AI summary

A liquid panel assembly configured to be used with an energy exchanger may include a support frame having one or more fluid circuits and at least one membrane secured to the support frame. Each of the fluid circuits may include an inlet channel connected to an outlet channel through one or more flow passages. A liquid is configured to flow through the fluid circuits and contact interior surfaces of the membrane(s). The fluid circuits are configured to at least partially offset liquid hydrostatic pressure with friction loss of the liquid flowing within the fluid circuits to minimize, eliminate, or otherwise reduce pressure within the liquid panel assembly.