Ester Refrigerant Oil with Branched Fatty Acids for Difluoromethane Compatibility
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional ester-based refrigerating machine oils exhibit inadequate compatibility and lubricity when used with difluoromethane refrigerants, making it difficult to achieve the necessary viscosity and performance.
Innovation Solution
A refrigerating machine oil composed of a polyhydric alcohol fatty acid ester with a molar ratio of C4-C6 fatty acid and C7-C9 branched fatty acid between 30:70 and 70:30, primarily featuring 2-methylpropanoic acid and 3,5,5-trimethylhexanoic acid, which ensures high compatibility and lubricity with difluoromethane refrigerants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ester-based refrigerating machine oils are used with difluoromethane refrigerants, then the oils can provide basic lubrication, but the compatibility between refrigerant and oil is insufficient, causing the oil to pool in the cycle and reduce lubrication effectiveness
Solution Approach 1:
The patent changes the chemical composition parameters of the ester-based refrigerating machine oil by specifying precise molar ratios of different fatty acids (C4-C6: 30-70%, C7-C9: 30-70%, C10-C12: 10-40%) to optimize compatibility with difluoromethane refrigerants and prevent oil pooling in the cycle
Solution Approach 2:
The patent creates a composite ester oil formulation by combining multiple fatty acid components (including 2-methylpropanoic acid, 3,5,5-trimethylhexanoic acid, and other branched-chain fatty acids) with polyhydric alcohols to achieve both refrigerant compatibility and proper lubrication characteristics
2Reliability
If conventional ester-based refrigerating machine oils are used with difluoromethane refrigerants, then the oils can maintain viscosity, but the lubricity is insufficient, resulting in poor lubrication performance
Solution Approach 1:
The patent optimizes the viscosity and lubricity parameters by controlling the molecular structure of the ester oil through specific fatty acid selection (particularly 2-methylpropanoic acid and 3,5,5-trimethylhexanoic acid) and their molar ratios, ensuring adequate lubrication film strength while maintaining appropriate viscosity levels
Solution Approach 2:
The patent introduces specific branched-chain fatty acid components with particular molecular structures that provide enhanced lubricity at the lubrication interface, while the overall oil composition maintains the necessary viscosity for proper circulation and film formation
3Reliability
If different refrigerating machine oils are developed for different refrigerants, then the compatibility and performance can be optimized, but the device complexity and development cost increase
Solution Approach 1:
The patent develops a multi-functional ester-based refrigerating machine oil formulation that achieves compatibility with difluoromethane refrigerants while maintaining proper lubrication and circulation characteristics, reducing the need for completely separate oil formulations for different refrigerant types
Data Source
AI summary
The refrigerating machine oil of the invention includes an ester of a polyhydric alcohol and a fatty acid, wherein the molar ratio of C4-C6 fatty acid and C7-C9 branched fatty acid in the fatty acid is between 15:85 and 90:10, the C4-C6 fatty acid includes 2-methylpropanoic acid, and the ratio of the total C4-C6 fatty acid and C7-C9 branched fatty acid in the total fatty acids composing the ester is at least 20 mol%. The working fluid composition for a refrigerating machine according to the invention comprises the refrigerating machine oil, a difluoromethane refrigerant and/or an unsaturated fluorinated hydrocarbon refrigerant.