Adsorbent Heat Exchanger Coating to Prevent Cracking and Clogs

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional adsorption heat exchangers face issues such as adsorbent layer cracking, non-uniform coating, and reduced performance due to adsorbent expansion and contraction during the manufacturing process, leading to peeling off and increased drying time, as well as clogs caused by narrowed clearances between fins.

Innovation Solution

A method is developed to form an adsorbent layer by applying slurry with a reduced water content, using a solvent that primarily contains alcohol, to minimize adsorbent deformation and ensure uniform dispersion, thereby preventing cracking and non-uniform coating, and improving water absorption performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If water is used as the solvent in slurry for forming the adsorbent layer, then the adsorbent particles expand by absorbing water, but this causes cracking and peeling off of the adsorbent layer during drying

Engineering Contradiction:
Improvewater absorption capacityVSAvoidadsorbent layer integrity
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent changes the solvent parameter from water to alcohol (or water-free solvent) to eliminate the expansion-contraction cycle that causes cracking. This parameter change resolves the contradiction by allowing the adsorbent to be applied without undergoing harmful volume changes, while still forming an effective adsorbent layer through solvent evaporation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces alcohol as an intermediary solvent that does not cause adsorbent expansion. The alcohol serves as a temporary carrier that can be easily evaporated, allowing the adsorbent to be applied uniformly without the harmful effects of water absorption and subsequent contraction during drying.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If water is used as the solvent, then the adsorbent absorbs a large amount of water, but this increases the drying time

Engineering Contradiction:
Improvewater absorption capacityVSAvoiddrying time
Core Design Contradiction:
Quantity of substanceVSLoss of time

Solution Approach 1:

The patent changes the solvent from water to alcohol, which has different absorption and evaporation characteristics. The adsorbent does not absorb alcohol to the same extent as water, and alcohol evaporates more quickly, thereby reducing the drying time while maintaining the ability to form an effective adsorbent layer.

Inventive Principle:
Principle #35Parameter changes

3Quantity of substance

If the adsorbent particles expand by absorbing water, then the clearance between fins is narrowed, but this causes clogs and reduces liquidity

Engineering Contradiction:
Improvewater absorption capacityVSAvoidairflow liquidity
Core Design Contradiction:
Quantity of substanceVSEase of operation

Solution Approach 1:

The patent changes the solvent parameter to prevent adsorbent expansion. By using alcohol instead of water, the adsorbent particles maintain their original size during application, preventing clearance narrowing and maintaining proper airflow liquidity and preventing clogs.

Inventive Principle:
Principle #35Parameter changes

4Strength

If the adsorbent is applied in expanded state, then the binder coverage increases, but this degrades the water absorption performance

Engineering Contradiction:
Improvebinder coverageVSAvoidwater absorption performance
Core Design Contradiction:
StrengthVSQuantity of substance

Solution Approach 1:

The patent changes the solvent parameter to prevent adsorbent expansion during application. This ensures that the adsorbent maintains its original particle size and porosity, preserving its water absorption performance while still achieving adequate binder coverage for layer formation.

Inventive Principle:
Principle #35Parameter changes

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 solution effectively prevents cracking and non-uniform coating, maintains uniform hygroscopic performance, reduces binder coverage, and prevents peeling off and clogs, ensuring efficient water absorption and reduced drying time.

Implementation Method 1

the adsorbent particles temporarily expanded by absorbing water

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

drying the slurry, thereby forming an adsorbent layer

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP2434243B1Method for producing heat exchanger
Publication Date: 2016.11.02 DAIKIN INDUSTRIES LTD
  • EP2434243B1 patent drawingFigure 1(A)~1(B)
  • EP2434243B1 patent drawingFigure 2
  • EP2434243B1 patent drawingFigure 3

AI summary

In an adsorption heat exchanger (20), adsorbent (31) expanded by absorbing moisture and contracted by dissipating moisture is supported on a surface of a heat exchanger body (25). An adsorbent layer (30) containing the adsorbent (31) is formed on the surface of the heat exchanger body (25) by applying slurry (32) containing the adsorbent (31) in a contracted state to the surface of the heat exchanger body (25) and drying the slurry (32). A solvent (34) of the slurry (32) contains alcohol as a main component.