Microporous Membrane Heat Exchanger for Corrosion-Resistant Dehumidification

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Solution Overview

Problem

Conventional liquid desiccant systems for dehumidification and cooling face challenges such as high energy costs, corrosion issues, and inefficiencies due to the use of corrosive brines and packed bed designs, which lead to increased fan power, pressure drops, and risks of desiccant carry-over, while also struggling with uniform desiccant distribution and high-temperature material stress.

Innovation Solution

A system utilizing a microporous membrane with a liquid desiccant flowing as a falling film, combined with a turbulator to induce turbulence in the air stream and a thermally conductive support plate, along with a siphoning drain system to maintain membrane flatness and prevent desiccant carry-over, and a flexible spacer to manage temperature differences and adhesion stresses, allowing for efficient heat and moisture transfer without contaminating the air stream.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional packed bed designs are used for liquid desiccant systems, then dehumidification can occur, but fan power and pressure drops increase significantly

Engineering Contradiction:

Improvedehumidification efficiencyVSAvoidfan power

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent employs microporous membranes as the core component to replace conventional packed bed structures. These membranes allow water vapor to pass through via diffusion and adsorption mechanisms while maintaining low pressure drop, thereby reducing fan power requirements while achieving effective dehumidification

Inventive Principle:

Principle #31Porous materials

2Productivity

If concentrated salt solutions (LiCl, LiBr, CaCl2) are used as liquid desiccants, then moisture removal efficiency improves, but corrosion risk increases

Engineering Contradiction:

Improvemoisture removal efficiencyVSAvoidcorrosion

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces microporous membranes as an intermediary barrier between the corrosive liquid desiccant and the structural components. This membrane allows moisture transfer while protecting the heat exchanger structure from direct contact with corrosive brines, thereby maintaining high moisture removal efficiency while eliminating corrosion risks

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system uses composite construction combining microporous membrane materials with corrosion-resistant heat exchanger structures. This composite approach enables the system to handle concentrated salt solutions effectively while preventing corrosion through the protective membrane barrier

Inventive Principle:

Principle #40Composite materials

3Productivity

If air flow rates are increased to improve cooling capacity, then dehumidification performance improves, but desiccant carry-over risk increases

Engineering Contradiction:

Improvecooling capacityVSAvoiddesiccant carry-over prevention

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The microporous membranes have precisely controlled pore sizes that allow water vapor molecules to pass through while blocking larger desiccant particles. This enables the system to operate at higher air flow rates for improved cooling capacity while maintaining reliable carry-over prevention through the physical filtration mechanism of the membrane

Inventive Principle:

Principle #31Porous materials

4Loss of energy

If the dehumidification process is adiabatic, then energy efficiency improves, but the air stream becomes warm and dry requiring post-cooling

Engineering Contradiction:

Improveenergy efficiencyVSAvoidair stream temperature

Core Design Contradiction:

Loss of energyVSTemperature

Solution Approach 1:

The patent utilizes the phase transition of water from vapor to liquid during absorption by the desiccant. This phase change releases latent heat that is transferred through the microporous membrane to the air stream, providing cooling effect while maintaining high energy efficiency through the adiabatic dehumidification process

Inventive Principle:

Principle #36Phase transitions

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 system achieves efficient dehumidification and cooling while reducing energy consumption, minimizing corrosion risks, and maintaining structural integrity under high temperatures, ensuring effective moisture capture and heat transfer without contaminating the air stream.

Implementation Method 1

a microporous membrane with a liquid desiccant flowing as a falling film

Methodology Applied

Scientific EffectPermeation: Permeation

Implementation Method 2

efficient moisture capture and heat transfer without contaminating the air stream

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 3

combined with a turbulator to induce turbulence in the air stream

Methodology Applied

Scientific EffectTurbulence: Turbulence

Implementation Method 4

a siphoning drain system to maintain membrane flatness and prevent desiccant carry-over

Methodology Applied

Scientific EffectSiphon: Syphon

Implementation Method 5

a thermally conductive support plate

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS9101874B2Methods and systems for turbulent, corrosion resistant heat exchangers

Publication Date: 2015.08.11 COPELAND LP

AI summary

Disclosed are various turbulent, corrosion-resistant heat exchangers used in desiccant air conditioning systems.