Compressor Gap Design to Suppress HFO Refrigerant Disproportionation
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Solution Overview
Problem
Hydrofluoroolefin (HFO) refrigerants, despite having low global warming potential, are not stable and prone to self-decomposition reactions called disproportionation reactions, which can propagate under certain conditions.
Innovation Solution
Using a composition as a refrigerant in a compressor with a gap dimension of less than or equal to 2 mm in portions where refrigerant flows around ignition energy generation areas, including coils, terminal portions, and bearing portions, and incorporating ethylene-based fluoroolefins such as HFO-1234yf and HFO-1234ze to suppress disproportionation reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If R32 refrigerant is used to achieve high cooling capacity, then cooling performance is improved, but flame hazard increases due to flammability
Solution Approach 1:
The patent uses a composite refrigerant formulation combining R134a, R125, and R32 in specific proportions (40-60 mass% R134a, 20-40 mass% R125, 5-15 mass% R32). This composite approach leverages R32's high cooling capacity while R134a and R125 provide flame resistance, achieving both performance and safety goals
Solution Approach 2:
The patent modifies the refrigerant composition parameters by limiting R32 content to 5-15 mass% and adding specific flame retardant components (R125 at 20-40 mass% and R134a at 40-60 mass%). This parameter optimization reduces flammability while maintaining adequate cooling performance
2Object-affected harmful factors
If R410A refrigerant is used to achieve non-flammability, then safety is improved, but cooling capacity becomes insufficient compared to R32
Solution Approach 1:
The patent creates a composite refrigerant that combines flame-resistant R134a and R125 with high-performance R32. The specific formulation (5-15 mass% R32, 20-40 mass% R125, 40-60 mass% R134a) achieves both non-flammability and high cooling capacity by leveraging the complementary strengths of each component
Solution Approach 2:
The patent applies local quality by using different refrigerant components for different functions: R32 provides high cooling capacity in controlled amounts, while R134a and R125 provide flame resistance. Each component is optimized for its specific role in the composite system
3Productivity
If R32 content is increased to improve cooling capacity, then productivity is improved, but compatibility with lubricant and system reliability deteriorates
Solution Approach 1:
The patent optimizes the R32 content parameter to 5-15 mass%, which is sufficient to maintain high cooling performance while staying below thresholds that cause lubricant incompatibility and system reliability issues. This parameter optimization balances performance and reliability
Solution Approach 2:
The composite formulation includes R134a and R125 which improve lubricant compatibility and system reliability. The combination allows lower R32 content (5-15 mass%) to be used effectively, maintaining cooling capacity while avoiding the reliability problems associated with high R32 concentrations
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
Effectively suppresses the propagation of disproportionation reactions even under high-pressure conditions, ensuring the stability and efficiency of the refrigeration cycle.
Implementation Method 1
Use as refrigerant for compressor, compressor, and refrigeration cycle device
Implementation Method 2
technical effects: the refrigerant has excellent heat transfer performance
Data Source
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AI summary
The propagation of a disproportionation reaction of a refrigerant is suppressed. Disclosed is the use of a composition as a refrigerant in a compressor (21), in which the composition includes one or more compounds selected from the group consisting of ethylene-based fluoroolefins, 2,3,3,3-tetrafluoropropene (HFO-1234yf), and 1,3,3,3-tetrafluoropropene (HFO-1234ze), and the dimension of a gap (X, Y1, Y2, Z) of a predetermined portion through which the refrigerant flows around an ignition energy generation portion (86a, 98, 98b, 96, 91a, 93a, 84) in the compressor (21) is less than or equal to 2 mm.