High-Strength Copper Alloy Tubes for CO2 Heat Exchangers
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Solution Overview
Problem
Conventional copper materials used in heat exchanger tubes for air conditioning and refrigeration systems are inadequate due to increased operating pressures with 'green' cooling media like CO2, requiring thicker tubes for strength, which increases weight and material costs, while maintaining desirable conductivity and formability.
Innovation Solution
Development of high-strength copper alloys with specific compositions such as CuFe(0.1)Sn(0.3) and CuZn(4.0)Sn(0.7) that offer improved tensile strength, processability, and thermal conductivity, allowing for reduced wall thickness and lower material costs, while maintaining burst pressure and cycle fatigue resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional copper materials are used in heat exchanger tubes for CO2 cooling media, then the tubes can maintain basic structural integrity, but the tube wall thickness must be increased to withstand high operating pressures, which increases weight and material costs
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of copper alloys, specifically controlling the content of elements such as Fe (0.01-1.0 wt%), Sn (0.01-1.0 wt%), Zn (0.01-5.0 wt%), and other trace elements to achieve optimal tensile strength while maintaining processability and thermal conductivity, thereby enabling thinner tube walls that reduce weight
Solution Approach 2:
The patent employs composite materials by creating multi-element copper alloys that combine copper with iron, tin, zinc, and other elements in specific proportions. This composite approach leverages the strength-enhancing effects of alloying elements while preserving the desirable properties of base copper, achieving high strength-to-weight ratio suitable for CO2 heat exchanger tubes
2Strength
If conventional copper materials are used in heat exchanger tubes for CO2 cooling media, then the tubes can maintain basic structural integrity, but the tube wall thickness must be increased to withstand high operating pressures, which increases material costs
Solution Approach 1:
The patent applies parameter changes by precisely controlling alloy composition parameters, including Fe (0.01-1.0 wt%), Sn (0.01-1.0 wt%), Zn (0.01-5.0 wt%), and trace elements (P, Si, Mn, etc.), to achieve optimal burst pressure resistance. This enables reduced material consumption while maintaining the required pressure withstand capability for CO2 cooling systems
Solution Approach 2:
The patent applies local quality by optimizing the distribution and concentration of alloying elements within the copper matrix to enhance strength properties specifically where needed for pressure resistance, allowing for more efficient material utilization and reduced overall material consumption in tube construction
3Strength
If copper alloy composition is optimized for high strength, then tensile strength and burst pressure resistance improve, but thermal conductivity and processability may deteriorate
Solution Approach 1:
The patent applies parameter changes by establishing specific compositional ranges for alloying elements (Fe: 0.01-1.0 wt%, Sn: 0.01-1.0 wt%, Zn: 0.01-5.0 wt%, and trace elements P: 0.01-0.1 wt%, Si: 0.01-0.5 wt%, Mn: 0.01-0.5 wt%) that simultaneously achieve high tensile strength and maintain adequate processability for manufacturing operations
Solution Approach 2:
The patent applies homogeneity by ensuring uniform distribution of alloying elements throughout the copper matrix, creating a homogeneous microstructure that provides consistent mechanical properties and predictable manufacturing behavior, thereby maintaining ease of manufacture while achieving high strength
4Strength
If copper alloy composition is optimized for high strength, then tensile strength and burst pressure resistance improve, but thermal conductivity may deteriorate
Solution Approach 1:
The patent applies parameter changes by carefully selecting and controlling the composition parameters of alloying elements, keeping their concentrations within specific ranges (Fe: 0.01-1.0 wt%, Sn: 0.01-1.0 wt%, Zn: 0.01-5.0 wt%) to minimize their impact on thermal conductivity while achieving the required tensile strength for CO2 heat exchanger applications
Data Source
AI summary
Alloys containing copper, iron, tin and, optionally, phosphorus or copper, zinc, tin and, optionally, phosphorus, which can be used in, for example, a copper alloy tube for heat exchangers that provides excellent fracture strength and processability for reducing the weight of the tube and for use in high pressure applications with cooling media such as carbon dioxide.