Compressor Insulation With High-Resistivity Refrigerant Oil
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Solution Overview
Problem
The refrigerant represented by Molecular Formula C3HmFn with a single double bond in its molecular structure has relatively low volume resistivity, leading to degraded voltage insulating properties and increased leakage current in refrigeration apparatus compressors.
Innovation Solution
The use of refrigerant oil with a volume resistivity of at least 1010 Ω·m at 20° C, primarily polyol ester or polyvinyl ether, which is compatible with the refrigerant and has a suitable kinetic viscosity, pour point, and surface tension to ensure effective lubrication and reduce leakage current, along with the incorporation of insulating materials like polyvinyl formal and polyamide imide in the electric motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If refrigerant represented by Molecular Formula 1 with a single double bond is used, then ozone layer protection is improved, but voltage insulating properties deteriorate
Solution Approach 1:
Refrigerant oil is introduced as an intermediary substance between the refrigerant and the compressor components. The refrigerant oil mixes with the refrigerant to form a refrigerant-oil mixture with higher volume resistivity than the refrigerant alone, thereby improving the voltage insulating properties while allowing the use of environmentally friendly refrigerant that protects the ozone layer.
2Adaptability or versatility
If refrigerant with low volume resistivity is used, then environmental compatibility is improved, but leakage current increases
Solution Approach 1:
Refrigerant oil serves as a mediator that modifies the electrical properties of the refrigerant. By mixing refrigerant oil with the low-volume-resistivity refrigerant, the resulting mixture achieves higher volume resistivity, thereby reducing leakage current from the electric motor while maintaining the use of environmentally compatible refrigerant.
Solution Approach 2:
The volume resistivity parameter of the refrigerant system is changed by adding refrigerant oil. The refrigerant oil has higher volume resistivity than the refrigerant alone, and their mixture creates a refrigerant-oil mixture with optimized volume resistivity characteristics that reduce leakage current while maintaining environmental compatibility.
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 configuration enhances the voltage insulating properties, reduces leakage current, and improves the operational efficiency of the refrigeration apparatus by ensuring adequate lubrication and preventing refrigerant decomposition due to friction heat.
Implementation Method 1
Refrigerant oil having volume resistivity of equal to or greater than 1010 Ω·m at 20° C. is used for the compressor (30)
Implementation Method 2
the refrigerant oil having a relatively-broad range of the volume resistivity is used for the compressor (30)
Data Source
AI summary
A refrigeration apparatus (20) includes a refrigerant circuit (10) in which refrigerant is circulated by a compressor (30) to perform a refrigeration cycle. The compressor (30) includes a fluid machine (82) for compressing refrigerant; and an electric motor (85) for driving the fluid machine (82). Refrigerant oil having volume resistivity of equal to or greater than 1010 Ω·m at 20° C. is used for the compressor (30).