Carbon-Stabilized Refrigerant Composition Against Decomposition

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Solution Overview

Problem

Existing refrigerants such as HFO-1132(E/Z), HFO-1132a, HFO-1123, and FO-1114 suffer from instability, leading to decomposition and oxidation, which affects the performance of air-conditioning cycles.

Innovation Solution

Incorporating carbon particles, such as carbon fibers, carbon nanotubes, graphene, or graphite, into the refrigerant composition, along with water, to enhance stability by suppressing decomposition and oxidation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If refrigerant R-134a is used as a replacement for R-12, then environmental protection is improved, but compatibility with original system oils (mineral oil and alkyl benzene) deteriorates

Engineering Contradiction:
Improveozone layer depletionVSAvoidrefrigerant-oil compatibility
Core Design Contradiction:
Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The patent introduces polyolester oil as an intermediary substance that bridges the incompatibility between R-134a refrigerant and traditional oils. The polyolester oil contains specific chemical groups that are compatible with both the HFC-134a refrigerant molecules and provide proper lubrication, thus mediating the interaction between refrigerant and lubricant in the air conditioning system

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the chemical composition parameters of the lubricant from mineral oil or alkyl benzene to polyolester oil with specific molecular structure characteristics. This parameter change in oil chemistry enables proper miscibility and stability with R-134a refrigerant, resolving the compatibility issue while maintaining environmental benefits

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If polyolester oil is used to improve R-134a compatibility, then refrigerant-oil compatibility is improved, but cost increases

Engineering Contradiction:
Improverefrigerant-oil compatibilityVSAvoidsystem cost
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The patent optimizes the molecular weight parameters of polyolester oil within specific ranges (300-1000 for diester, 200-800 for triester) to achieve the desired compatibility and performance while controlling production costs. By defining specific parameter ranges, the patent enables manufacturers to produce cost-effective formulations that meet performance requirements

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If new refrigerant-oil combinations are developed, then compatibility is improved, but system reliability during transient operations deteriorates due to oil return issues

Engineering Contradiction:
Improverefrigerant-oil miscibilityVSAvoidoil return reliability
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent addresses oil return reliability by considering the dynamic behavior of refrigerant-oil mixtures during various operating conditions. The selected polyolester oil formulations maintain appropriate viscosity characteristics across temperature and pressure changes, ensuring that oil can return to the compressor reliably during transient operations while maintaining miscibility during steady-state operation

Inventive Principle:
Principle #15Dynamics

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 presence of carbon and water significantly reduces acid generation, enhancing the stability of the refrigerant and maintaining its performance over time.

Implementation Method 1

When a refrigerant R-134a and an oil are mixed together, they are required to be compatible with each other, i.e., they should be able to form a stable mixture and be separated easily

Methodology Applied
Scientific EffectMolecular interactions: Van der Waals Force

Data Source

PatentEP4227380B1Composition containing refrigerant, and method for stabilizing composition containing refrigerant
Publication Date: 2026.05.13 DAIKIN INDUSTRIES LTD

AI summary

An object of the present disclosure is to provide a composition having excellent stability of a refrigerant. Provided is a composition comprising a refrigerant and carbon, the refrigerant comprising at least one member selected from the group consisting of HFO-1234yf, HFO-1132(E/Z), HFO-1132a, HFO-1123, and FO-1114.