Total heat exchange element-purpose flow channel plate, total heat exchange element, total heat exchange ventilator, and total heat exchange element-purpose flow channel plate manufacturing method

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Solution Overview

Problem

The configuration of existing total heat exchange elements, when applied to countercurrent flow-type elements, can lead to a decrease in performance due to dew condensation, as the deliquescent salt added as a hydrophilic material can dissolve into the dew condensation water and flow away.

Innovation Solution

A total heat exchange element-purpose flow channel plate is designed with a corrugated form and a resin composition that includes a polypropylene base material with a low-density polyethylene having a branched structure, and a block copolymer based on polyethylene glycol for enhanced water vapor permeability, eliminating the need for deliquescent salt.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If deliquescent salt is added as a hydrophilic material to enhance water vapor permeability, then moisture exchange performance is improved, but the salt dissolves into dew condensation water and flows away, causing performance degradation

Engineering Contradiction:
Improvemoisture exchange performanceVSAvoiddeliquescent salt
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent removes the deliquescent salt component from the system entirely. Instead of using salt to achieve hydrophilicity and water vapor permeability, the invention employs a synthetic resin material (polypropylene with specific crystallinity and molecular weight characteristics) that provides the same moisture exchange function without the drawback of salt dissolution and loss.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the material parameters from inorganic deliquescent salt to organic synthetic resin with specific physical properties (crystallinity of 40-70%, molecular weight 100,000-500,000). This parameter change maintains the hydrophilic functionality while eliminating the substance loss problem, as the resin does not dissolve in water like salt does.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If conventional partitioning members are used in countercurrent flow-type heat exchange elements, then manufacturing is simplified, but dew condensation causes salt dissolution and performance decrease

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidheat exchange efficiency
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent uses a composite material approach by combining polypropylene base resin with specific additives and controlling the crystallinity structure to create a partitioning member that maintains both manufacturing ease and reliable heat exchange efficiency in dew condensation environments. The composite structure provides the necessary hydrophilicity and mechanical properties without using deliquescent salt.

Inventive Principle:
Principle #40Composite materials

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 solution effectively suppresses the decrease in performance associated with dew condensation, maintaining high total heat exchange efficiency and preventing the deliquescent salt from dissolving and flowing away.

Implementation Method 1

a block copolymer based on polyethylene glycol for enhanced water vapor permeability

Methodology Applied
Scientific EffectWater vapor permeability: Permeation

Implementation Method 2

a first membrane has both surfaces thereof being sandwiched between second membranes, where the first membrane is a water-insoluble membrane having a gas blocking property

Methodology Applied
Scientific EffectGas blocking property: Filter (physical)

Implementation Method 3

a resin composition that includes a polypropylene base material with a low-density polyethylene having a branched structure

Methodology Applied
Scientific EffectHydrophobicity: Hydrophobe

Data Source

PatentEP4269928B1Total heat exchange element-purpose flow channel plate, total heat exchange element, total heat exchange ventilator, and total heat exchange element-purpose flow channel plate manufacturing method
Publication Date: 2025.05.28 MITSUBISHI ELECTRIC CORP
  • EP4269928B1 patent drawingFigure 1
  • EP4269928B1 patent drawingFigure 2~3
  • EP4269928B1 patent drawingFigure 4~5

AI summary

A total heat exchange element-purpose flow channel plate is formed from a resin composition having heat conductivity and moisture permeability, containing at least one base material of a first base material and a second base material, and a moisture permeable material. The first base material is a polypropylene having a long chain branched hydrocarbon structure. The second base material is a polypropylene with addition of a low-density polyethylene having a branched structure. The moisture permeable material is a block copolymer based on a polyethylene glycol as a raw material.