Porous Copper Heat Exchanger Nanostructures
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Solution Overview
Problem
Metallic substrates used in thermo-adsorptive batteries become nonfunctional due to the adsorption of organic contaminants, rendering them hydrophobic and unable to maintain hydrophilicity over time, which affects their efficiency in heat exchange processes.
Innovation Solution
A hydrophilic, thermally conductive porous medium is created by uniformly forming nanostructures throughout the copper structure through anodizing in an oxidizing alkaline medium with specific ratios of NaClO2, NaOH, and Na3PO4·12H2O at 75°C, and applying pulsed electrochemical techniques to ensure uniform nanostructure growth, maintaining hydrophilicity even in the presence of contaminants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If metallic substrates are used in thermo-adsorptive batteries, then thermal conductivity and evaporation performance are improved, but the substrates become hydrophobic due to organic contaminant adsorption and lose functionality over time
Solution Approach 1:
The patent applies porous copper foam as the substrate material, which provides high surface area and capillary action for efficient evaporation while maintaining structural integrity. The porous structure enables uniform distribution of working fluid and enhances heat transfer efficiency while resisting contaminant adsorption that would otherwise cause hydrophobicity
Solution Approach 2:
The patent creates a composite structure by combining copper foam with a hydrophilic nanostructured coating layer. This composite approach maintains the excellent thermal conductivity of copper while the nanostructured surface layer prevents organic contaminant adsorption, ensuring long-term hydrophilicity and functionality in thermo-adsorptive battery operations
2Reliability
If nanostructures are formed uniformly throughout the porous structure, then hydrophilicity is maintained permanently in the presence of organic contaminants, but manufacturing complexity increases
Solution Approach 1:
The patent applies a preliminary surface treatment process where the copper foam substrate is first activated and then coated with a hydrophilic nanostructured layer before being integrated into the thermo-adsorptive battery. This preliminary action ensures permanent hydrophilicity is established in advance, preventing organic contaminant adsorption throughout the device's operational life
Solution Approach 2:
The patent utilizes controlled electrochemical parameters during the nanostructure formation process, including voltage, current density, electrolyte composition, and treatment time. By optimizing these parameters, the patent achieves uniform nanostructure distribution throughout the porous copper structure, ensuring permanent hydrophilicity while managing manufacturing complexity through parameter control
3Use of energy by moving object
If the porous medium self-regulates liquid-vapor contact lines, then pumping power is eliminated, but the balance of capillary and viscous forces requires precise structural control
Solution Approach 1:
The patent designs the porous copper foam structure to self-regulate the liquid-vapor contact line through an inherent balance between capillary forces (which draw liquid into the pores) and viscous forces (which resist flow). This self-service mechanism eliminates the need for external pumping power, as the structure automatically controls fluid distribution and phase change interfaces throughout operation
Solution Approach 2:
The patent employs porous copper foam with specifically controlled pore size distribution and porosity to achieve the precise balance of capillary and viscous forces required for self-regulation. The porous structure's geometric parameters are optimized to ensure that capillary pressure gradients naturally drive liquid-vapor contact line movement without external pumping, while maintaining manufacturing feasibility through available foam fabrication techniques
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 enables self-regulation of liquid-vapor contact lines without requiring pumping power, maintains high heat flux, and enhances both evaporation and condensation performance, preventing flooding and ensuring efficient operation in thermal engineering applications.
Implementation Method 1
anodizing a porous copper structure in an oxidizing alkaline medium at approximately 75° C., the oxidizing alkaline medium comprising a mixture of NaClO2, NaOH, Na3PO4.12H2O along with deionized water, whereby nanostructures are formed throughout the porous copper structure
Implementation Method 2
anodizing a porous copper structure in an oxidizing alkaline medium
Implementation Method 3
provide a balance of capillary and viscous forces to self-regulate a liquid-vapor contact line
Implementation Method 4
self-regulate a liquid-vapor contact line
Implementation Method 5
hydrophilic, thermally conductive porous medium
Data Source
AI summary
Heat exchange structure. A hydrophilic, thermally conductive porous medium includes nanostructures formed substantially uniformly throughout the porous medium providing a balance of capillary and viscous forces to self-regulate a liquid-vapor contact line. A suitable porous medium is copper. A method for making the structure is also disclosed.