Perfluoropolyether Additives for Refrigerant Oil Return

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Solution Overview

Problem

In refrigeration and air-conditioning systems, the poor miscibility of HFC refrigerants with conventional lubricants like mineral oil leads to poor oil return, reduced energy efficiency, and accelerated compressor wear, necessitating the use of more expensive synthetic lubricants.

Innovation Solution

The use of unsaturated fluorocarbons and perfluoropolyether additives in refrigerant or heat transfer fluid compositions improves oil return, lubrication, and energy efficiency, allowing for the use of conventional mineral oil while reducing compressor wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If HFC refrigerants are used with conventional mineral oil lubricants, then cost is reduced, but oil return deteriorates and energy efficiency decreases

Engineering Contradiction:
ImprovecostVSAvoidoil return
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent introduces a polar additive as an intermediary substance between the HFC refrigerant and mineral oil lubricant. This additive improves the miscibility and dispersibility of the lubricant in the refrigerant, enabling better oil return through heat exchangers without requiring expensive synthetic lubricants. The additive acts as a mediator that bridges the incompatibility between non-polar mineral oil and polar HFC refrigerants.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If HFC refrigerants are used with conventional mineral oil lubricants, then cost is reduced, but energy efficiency deteriorates

Engineering Contradiction:
ImprovecostVSAvoidenergy efficiency
Core Design Contradiction:
Quantity of substanceVSUse of energy by moving object

Solution Approach 1:

The polar additive serves as a mediator that prevents lubricant accumulation on heat exchange surfaces by improving oil return. This eliminates the insulating layer that would otherwise reduce heat transfer efficiency and increase energy consumption, thereby maintaining energy efficiency while using cost-effective mineral oil lubricants.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Quantity of substance

If HFC refrigerants are used with conventional mineral oil lubricants, then cost is reduced, but compressor wear accelerates

Engineering Contradiction:
ImprovecostVSAvoidcompressor wear
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The polar additive improves the dispersibility of the mineral oil lubricant in the HFC refrigerant, ensuring proper lubrication delivery to the compressor. This maintains adequate lubrication film formation and reduces compressor wear, allowing the use of inexpensive mineral oil instead of expensive synthetic lubricants.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Reliability

If synthetic lubricants like polyolesters are used with HFC refrigerants, then oil return improves, but cost increases and device complexity increases

Engineering Contradiction:
Improveoil returnVSAvoidcost
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent uses a small amount of polar additive (0.01-5% by weight) mixed with conventional mineral oil to achieve the performance benefits of expensive synthetic lubricants. This approach replaces the need for costly synthetic lubricants like polyolesters while maintaining good oil return properties throughout the system lifecycle.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention creates a composite lubricant system by combining mineral oil base stock with polar additives. This composite formulation achieves the miscibility and oil return characteristics of synthetic lubricants while retaining the cost advantages and simplicity of conventional mineral oils.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentUS9315709B2Refrigerant additive compositions containing perfluoropolyethers
Publication Date: 2016.04.19 THE CHEMOURS CO FC LLC

AI summary

The present invention relates to compositions and processes of using perfluoropolyether to maintain or improve the oil return, lubrication, cooling capacity, or energy efficiency of a refrigeration, air conditioning or heat transfer system.