Refrigerator, refrigerator oil, working fluid composition for refrigerator
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Solution Overview
Problem
Reducing the viscosity of refrigerating machine oil to improve efficiency while maintaining lubricity in refrigerating machines, as low-viscosity base oils tend to compromise refrigerant compatibility and lubricity at low temperatures.
Innovation Solution
A refrigerating machine oil composition comprising a first base oil with good refrigerant compatibility at temperatures 30° C. or lower and a second base oil with lower kinematic viscosity and narrower compatibility, reducing viscosity while maintaining refrigerant dissolved viscosity to enhance efficiency and lubricity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a low-viscosity base oil is used to reduce the viscosity of refrigerating machine oil, then the efficiency of the refrigerating machine is improved, but the refrigerant compatibility and lubricity are compromised
Solution Approach 1:
The patent uses a composite base oil composition comprising multiple types of base oils (mineral oil, synthetic hydrocarbon oil, and/or synthetic ester oil) in specific proportions. This composite approach allows the refrigerating machine oil to achieve low viscosity (improving efficiency) while maintaining adequate refrigerant compatibility and lubricity through the synergistic effects of different base oil components.
Solution Approach 2:
The patent specifies precise parameter ranges for the base oil composition, including viscosity at 40°C (5 to 50 mm²/s), viscosity at −20°C (50 to 5000 mm²/s), and viscosity index (80 or more). By controlling these parameters and the proportions of different base oils, the invention achieves the optimal balance between efficiency and lubricity.
2Productivity
If the viscosity of refrigerating machine oil is reduced to improve efficiency, then the oil flows better, but the refrigerant dissolved viscosity decreases making it difficult to hold the oil film
Solution Approach 1:
The composite base oil composition maintains adequate refrigerant dissolved viscosity by combining multiple base oil types with different interaction characteristics with the refrigerant. This ensures the oil film holding capability is preserved even when the overall viscosity is reduced for efficiency improvements.
Solution Approach 2:
The patent controls the viscosity index to be 80 or more, which ensures that the viscosity does not drop excessively when refrigerant dissolves in the oil. This parameter control maintains the oil film strength while allowing lower base viscosity for efficiency.
3Reliability
If a base oil with good refrigerant compatibility is used, then the oil returns to the compressor properly, but the viscosity remains high reducing machine efficiency
Solution Approach 1:
The patent combines multiple base oil types (mineral oil, synthetic hydrocarbon oil, and/or synthetic ester oil) in specific proportions to achieve both good refrigerant compatibility (for proper oil return) and low viscosity (for efficiency). No single base oil type can simultaneously optimize both properties, but the composite composition achieves this balance.
Solution Approach 2:
By specifying the viscosity at 40°C in the range of 5 to 50 mm²/s and viscosity index of 80 or more, the patent achieves the optimal balance between compatibility-induced viscosity and efficiency-required low viscosity.
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
The solution improves refrigerating machine efficiency by reducing viscosity and maintaining lubricity, especially at low temperatures, thereby enhancing startability and performance in cold conditions.
Implementation Method 1
a liquid mixture of a refrigerating machine oil and a refrigerant is separated into two layers at a refrigerating machine oil content of 10 to 40% by mass and a temperature range of −40° C. to 60° C.
Data Source
AI summary
One aspect of the present invention is a refrigerating machine including a refrigerant circulation system including a compressor, a condenser, an expansion mechanism, and an evaporator, and the refrigerant circulation system being filled with a refrigerant and a refrigerating machine oil, wherein the refrigerating machine oil contains: a first base oil having a compatible region with the refrigerant in a range of a temperature of 30° C. or lower and an oil ratio of 1 to 80% by mass; and a second base oil having a kinematic viscosity at 40° C. lower than the first base oil and having a narrower compatible region with the refrigerant than the first base oil.