Refrigeration Circuit Additives to Prevent R1234yf Polymerization
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Solution Overview
Problem
The use of new-type refrigerant R1234yf in automotive air conditioning systems is threatened by radical generation, which can lead to polymerization and deterioration of refrigeration circuit performance due to the presence of double bonds vulnerable to attack by radicals like Cl-, OH-, and O3, especially when electric compressors with high voltage are used.
Innovation Solution
Incorporating a radical-capturing agent or polymerization inhibitor at sites prone to radical generation within the refrigeration circuit, such as near high-voltage areas in electric compressors, either through coating or compounding with circuit materials, to prevent radical formation and subsequent polymerization of R1234yf.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a new-type refrigerant R1234yf with double bond is used to improve Global Warming Potential, then environmental performance is improved, but the refrigerant becomes vulnerable to radical attacks causing polymerization and performance deterioration
Solution Approach 1:
A radical-capturing agent is introduced as an intermediary substance in the refrigeration circuit to intercept radicals before they can attack the R1234yf refrigerant. The agent acts as a mediator that captures chlorine radicals, hydroxyl radicals, and other reactive species, preventing them from initiating polymerization reactions with the double bond in R1234yf, thus protecting the refrigerant while maintaining the environmental benefits.
2Productivity
If an electric compressor with high voltage is used to improve compression efficiency, then productivity is improved, but radical generation increases leading to R1234yf polymerization
Solution Approach 1:
The high voltage in the electric compressor, which originally generates harmful radicals, is reframed as an opportunity to place radical-capturing agents precisely where they are most needed. The compressor housing or internal components are coated with or contain these agents, converting the harmful radical generation zone into a controlled environment where radicals are immediately captured, thus enabling the use of efficient electric compressors without suffering from polymerization problems.
3Stability of the object's composition
If the double bond in R1234yf is attacked by radicals, then chemical stability is improved through reaction, but polymerization occurs causing refrigerant characteristics to change and performance to deteriorate
Solution Approach 1:
Radical-capturing agents are pre-positioned in the refrigeration circuit to perform preliminary anti-action against potential radical attacks on R1234yf. These agents are strategically placed in the compressor and other high-risk areas to intercept radicals before they can reach and attack the refrigerant molecules, preventing the initiation of polymerization reactions and maintaining the chemical stability and performance characteristics of the refrigerant.
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 approach effectively stabilizes the refrigeration circuit performance by preventing R1234yf polymerization, ensuring long-term efficient operation and reducing Global Warming Potential by suppressing radical generation across various compressor types, including electric and belt-driven compressors.
Implementation Method 1
the radical-capturing agent or the polymerization inhibitor is provided at a site, which is preferably the neighborhood of a site where the radical may be generated, in the refrigeration circuit
Implementation Method 2
the π bond is generally weak against attacks from the outside. If the π bond is destroyed, the double bond might be opened, and a macromolecule of -C-C-C-C....C- might be formed by a chain reaction
Data Source
Figure 1
AI summary
Provided is a refrigeration circuit including a compressor such as a compressor having a built-in motor, a condenser, a pressure reduction and expansion means, and an evaporator. The refrigeration circuit uses R1234yf as a refrigerant and provides therein a radical-capturing agent or a polymerization inhibitor. When the R1234yf as a new refrigerant is used and there is a possibility that radicals are formed, it is possible to prevent or suppress generation of radicals and prevent polymerization of R1234yf so that a target performance can be realized even when the new refrigerant is used.