Refrigerant Oil Composition for CO2 Heat Stability
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Solution Overview
Problem
The heat stability of compositions for refrigerators using mixed refrigerants and refrigerator oils varies depending on the selection of refrigerant and oil composition, particularly when carbon dioxide is included to reduce global warming potential.
Innovation Solution
A composition for a refrigerator comprising a mixed refrigerant with a hydrofluorocarbon compound and carbon dioxide, where the hydrofluorocarbon content is less than 25% and the base oil consists of polyvinyl ether and polyalkylene glycol, with specific ratios to enhance heat stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If carbon dioxide is used as a refrigerant to reduce global warming potential, then environmental performance is improved, but heat stability of the composition may deteriorate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the composition ratios of hydrofluorocarbon compounds (less than 25 mass%) and carbon dioxide (50-97 mass%) in the mixed refrigerant, and by selecting specific base oil types (polyvinyl ether and polyalkylene glycol) with defined viscosity ranges. These parameter optimizations ensure the composition maintains excellent heat stability while achieving low global warming potential through high carbon dioxide content.
2Productivity
If hydrofluorocarbon compound content is increased to improve refrigerant performance, then cooling efficiency is improved, but heat stability of the composition deteriorates
Solution Approach 1:
The patent optimizes the hydrofluorocarbon compound content to be less than 25 mass% (preferably 3-20 mass%) in the mixed refrigerant composition. This parameter control balances cooling efficiency requirements with heat stability constraints, ensuring that sufficient hydrofluorocarbon is present for effective heat transfer while maintaining composition stability under thermal conditions.
Solution Approach 2:
The patent creates a composite refrigerant composition by combining carbon dioxide (50-97 mass%) as the primary refrigerant with hydrofluorocarbon compounds (less than 25 mass%) as additives, and pairs this with specific refrigerator oils containing polyvinyl ether or polyalkylene glycol base oils. This composite structure leverages the low GWP of carbon dioxide while using hydrofluorocarbon compounds to enhance refrigerant performance, achieving both environmental and functional requirements.
Data Source
AI summary
Provided is a composition for a refrigerator, which is a mixture of a mixed refrigerant containing carbon dioxide and being a refrigerant having a low global warming potential, and a refrigerator oil, and is excellent in heat stability. The composition for a refrigerator is a composition for a refrigerator, including: a mixed refrigerant; and a refrigerator oil containing a base oil, wherein the mixed refrigerant contains a hydrofluorocarbon compound and carbon dioxide, wherein a content of the hydrofluorocarbon compound is less than 25 mass% with respect to a total amount of the mixed refrigerant, and wherein the base oil contains one or more kinds selected from the group consisting of: a polyvinyl ether; and a polyalkylene glycol.