Hydrophilic Heat Exchanger Fin Coating for Odor and Draft Control
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Solution Overview
Problem
Air conditioning apparatuses experience odor issues due to the retention of odoriferous components in hydrophilic layers of heat exchanger fins, which are exacerbated when the system transitions from a thermo-on to a thermo-off state, and reducing hydrophilicity to minimize water content increases draft resistance and allows condensed water to scatter.
Innovation Solution
A fin design for heat exchangers featuring a base material with a corrosion-resistant layer between the base material and a hydrophilic layer, where the hydrophilic layer has a water content of 400 mg/dm² or less and a contact angle of 50 degrees or less with water, ensuring reduced odor retention and draft resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the water content of the hydrophilic layer is reduced to minimize odor retention, then odor is suppressed, but the hydrophilicity of the fin surfaces is reduced causing condensed water to be repelled and draft resistance to increase
Solution Approach 1:
The patent applies parameter changes by precisely controlling the water content of the hydrophilic layer within the range of 100-400 mg/dm² and the contact angle within 0-50 degrees. This optimization balances the competing requirements: sufficient hydrophilicity to allow condensed water to flow down efficiently (reducing draft resistance) while limiting water retention capacity to minimize odoriferous component accumulation. The corrosion-resistant layer is also controlled at 1-10 μm thickness to achieve this balance.
Solution Approach 2:
The patent employs composite materials by combining a base material (aluminum or aluminum alloy) with a corrosion-resistant layer and a hydrophilic layer. This multi-layer composite structure allows each layer to perform its specific function: the base material provides structural integrity, the corrosion-resistant layer protects against degradation, and the hydrophilic layer controls water interaction. The composite structure enables simultaneous achievement of low draft resistance and low odor retention.
2Object-affected harmful factors
If the contact angle of the hydrophilic layer is reduced to improve condensed water flow, then draft resistance decreases, but water content retention increases leading to more odoriferous component accumulation
Solution Approach 1:
The patent resolves this contradiction through parameter optimization by establishing specific ranges for contact angle (0-50 degrees) and water content (100-400 mg/dm²). The contact angle is controlled to be low enough to ensure condensed water flows down efficiently, reducing draft resistance. Simultaneously, the water content is limited to prevent excessive retention of odoriferous components. The corrosion-resistant layer thickness (1-10 μm) is also optimized to support this balance.
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 minimizes odor and draft resistance while preventing condensed water scattering, maintaining sufficient hydrophilicity and heat exchange performance.
Implementation Method 1
a water content of the hydrophilic layer per square decimeter of a surface of the hydrophilic layer is 400 mg/dm2 or less
Implementation Method 2
A contact angle of a surface of the hydrophilic layer with water is 50 degrees or less
Implementation Method 3
A corrosion-resistant layer is provided between the base material and the hydrophilic layer
Data Source
AI summary
A fin for a heat exchanger of an air conditioning apparatus includes a base material, a hydrophilic layer, and a corrosion-resistant layer provided between the base material and the hydrophilic layer. A contact angle of a surface of the hydrophilic layer with water is no more than 50 degrees. A water content of the hydrophilic layer per dm2 of the surface of the hydrophilic layer being at least 60 mg/dm2 and no more than 300 mg/dm2.