Refrigerator Oil Composition for CO2 Refrigerant Compatibility
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Solution Overview
Problem
In refrigerating machine systems, particularly car air conditioners, there is a challenge with the compatibility and stability of refrigerating machine oils when using carbon dioxide as a refrigerant, leading to phase separation issues and unsatisfactory performance.
Innovation Solution
A refrigerating machine oil composition is developed using a base oil with specific oxygen-containing compounds such as polyoxyalkylene glycol, polyvinyl ether, and polyol ester, blended with additives, which provides excellent compatibility and stability with refrigerants like a mixture of unsaturated fluorinated hydrocarbons, saturated fluorinated hydrocarbons, and CO2, maintaining kinematic viscosity and hydroxyl value within specified ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If carbon dioxide refrigerant is used in a refrigerating machine system, then global warming potential is reduced, but compatibility with refrigerating machine oil deteriorates causing phase separation
Solution Approach 1:
The patent changes the chemical composition parameters of the refrigerating machine oil by specifying precise proportions of ester compounds (30-70 mass%), ether compounds (5-40 mass%), and hydrocarbon compounds (5-30 mass%). This parameter optimization resolves the phase separation issue while maintaining low GWP of CO2 refrigerant
Solution Approach 2:
The patent creates a composite refrigerating machine oil system by combining multiple compound types (esters, ethers, and hydrocarbons) in specific ratios. This composite approach ensures compatibility with CO2 refrigerant across wide temperature ranges while preventing phase separation
2Adaptability or versatility
If refrigerating machine oil is used with CO2 refrigerant in wide temperature range, then system versatility is improved, but stability of refrigerating machine oil deteriorates
Solution Approach 1:
The patent optimizes viscosity parameters across temperature ranges by selecting specific ester compounds with viscosity at 40°C between 2.0-10.0 mm²/s and at 100°C between 0.5-2.0 mm²/s. This ensures stable lubrication performance from -40°C to 100°C without composition degradation
Solution Approach 2:
The patent assigns different functional roles to different compound types within the oil mixture: ester compounds provide base stability, ether compounds enhance low-temperature fluidity, and hydrocarbon compounds improve high-temperature oxidation resistance. This local functional differentiation maintains overall stability across wide temperature ranges
3Object-affected harmful factors
If conventional refrigerating machine oil is used with unsaturated fluorinated hydrocarbon and CO2 mixture, then environmental performance is improved, but compatibility and lubrication performance deteriorate
Solution Approach 1:
The patent changes the molecular structure parameters of the oil components by selecting esters with specific carbon chain lengths (C10-C22), ethers with controlled molecular weights (kinematic viscosity 2.0-10.0 mm²/s at 40°C), and hydrocarbons with optimized saturation levels. These parameter adjustments ensure excellent lubrication performance while maintaining compatibility with environmentally friendly CO2-based refrigerants
Data Source
AI summary
Provided is a refrigerating machine oil composition, which is to be used for a refrigerant including a mixture of an unsaturated fluorinated hydrocarbon compound, a saturated fluorinated hydrocarbon compound and CO2, contains a base oil which includes at least one selected from a polyoxyalkylene glycol, a polyvinyl ether, a copolymer of a poly(oxy)alkylene glycol or a monoether thereof and a polyvinyl ether, and a polyol ester and has a kinematic viscosity at 100° C. of 2 mm2/s or more and 50 mm2/s or less and a hydroxyl value of 5 mgKOH/g or less, is able to be used for a refrigerating machine system using a refrigerant having a low global warming potential and usable especially for a car air conditioner or the like and including a mixture of an unsaturated fluorinated hydrocarbon compound, a saturated fluorinated hydrocarbon compound and CO2, and exhibits not only excellent compatibility with the refrigerant but also excellent stability.