Complex Ester Refrigeration Oil for Hydrocarbon Systems
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Solution Overview
Problem
Conventional refrigerating machine oils have compatibility and solubility issues with hydrocarbon refrigerants like propane, leading to viscosity reduction, lubricity loss, and electrical insulating property deficiencies, making it difficult to maintain proper refrigeration performance while minimizing refrigerant filling amounts.
Innovation Solution
A complex ester-based refrigerating machine oil is developed, comprising a neopentyl polyol, a dibasic acid, and a monohydric or fatty acid, with specific chemical structures and ratios, which provides compatibility, solubility, and stability, and is used in conjunction with hydrocarbon refrigerants having 2 to 4 carbon atoms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional refrigerating machine oil (mineral oil, alkylbenzene, polyol ester) is used with hydrocarbon refrigerant, then the refrigerant is excessively dissolved in the oil, but the viscosity of the lubricating oil is lowered and proper viscosity cannot be retained in sliding portions
Solution Approach 1:
The patent changes the chemical parameters of the base oil by selecting specific ester oils with controlled molecular weight and chemical structure. The ester oil is designed to have specific solubility parameters that limit hydrocarbon refrigerant dissolution while maintaining adequate viscosity, thereby resolving the contradiction between refrigerant compatibility and viscosity stability.
Solution Approach 2:
The patent uses a composite approach by combining ester oil as the base oil with specific additives. This composite lubricating oil formulation achieves both good compatibility with hydrocarbon refrigerants and maintained viscosity characteristics, as the additive package compensates for any viscosity reduction while the ester base provides appropriate solubility characteristics.
2Adaptability or versatility
If mineral oil or alkylbenzene oil is used as hydrocarbon refrigerating machine oil, then the viscosity is reduced by refrigerant dissolution, but lubricity cannot be retained
Solution Approach 1:
The patent changes the chemical composition parameters by selecting ester oil with specific molecular structure and weight. This ester-based composition maintains lubricity even when hydrocarbon refrigerant is dissolved, because the ester molecular structure provides film-forming characteristics that conventional mineral oils lack, thereby maintaining reliable lubrication under refrigerant dissolution conditions.
Solution Approach 2:
The ester oil acts as an intermediary substance that mediates between the hydrocarbon refrigerant and the metal surfaces. It provides a lubricating film that prevents direct metal-to-metal contact while being compatible with hydrocarbon refrigerants, thus maintaining lubricity where conventional oils fail.
3Productivity
If the filling amount of refrigerant is increased to attain given cooling capacity, then cooling capacity is improved, but the friction increases due to viscosity reduction
Solution Approach 1:
The patent changes the viscosity parameters of the lubricating oil by selecting ester oil with appropriate molecular weight and structure. This ensures that even when refrigerant filling amount is increased for higher cooling capacity, the lubricating oil maintains sufficient viscosity to prevent excessive friction, because the ester base oil is less susceptible to viscosity reduction from refrigerant dissolution.
4Adaptability or versatility
If conventional refrigerating machine oil is used, then the viscosity is lowered by refrigerant dissolution, but electrical insulating property is insufficient
Solution Approach 1:
The patent employs a composite lubricating oil formulation using ester oil as base oil with carefully selected additives. This composite structure maintains electrical insulating properties while providing compatibility with hydrocarbon refrigerants, as the ester base and additive package work together to preserve dielectric strength even when refrigerant is dissolved in the oil.
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 complex ester-based oil maintains viscosity and lubricity, reduces refrigerant filling requirements, and enhances electrical insulating properties and stability, making it suitable for hydrocarbon refrigerant systems.
Implementation Method 1
the hydrocarbon refrigerant has a small polarity, and hence is excessively dissolved in the conventional refrigerating machine oil such as the mineral oil, alkylbenzene or polyol ester
Data Source
AI summary
A working fluid composition for a refrigerating machine of the present invention comprises: a refrigerating machine oil comprising a complex ester as a base oil; and a hydrocarbon refrigerant having 2 to 4 carbon atoms, the complex ester being obtainable by further esterifying, with at least one selected from a monohydric alcohol having 1 to 20 carbon atoms and a fatty acid having 2 to 20 carbon atoms, an ester intermediate obtained by reacting a neopentyl polyol with a dibasic acid, and having an acid value of 0.5 mgKOH/g or less, the refrigerating machine oil having a kinematic viscosity at 100°C of 2 to 50 mm2/s.