Coolant
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Solution Overview
Problem
Existing refrigerants face challenges in achieving low temperatures while being environmentally friendly and safe, particularly in achieving temperatures below -60°C, due to limitations in Global Warming Potential (GWP) and flammability, which affects cooling capacity and safety regulations.
Innovation Solution
A refrigerant mixture comprising carbon dioxide, difluoromethane, pentafluoroethane, 2,3,3-tetrafluoropropene, and 1,1,1,2-tetrafluoroethane, with specific mass proportions, is used to achieve low GWP and non-flammability, allowing for temperatures down to -60°C while maintaining safety and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If carbon dioxide is used as a refrigerant component to achieve low GWP and non-flammability, then environmental safety and flammability resistance are improved, but the achievable temperature is limited to above -56.6°C due to its freezing point
Solution Approach 1:
The patent uses a composite refrigerant mixture containing carbon dioxide (24-54 mass%), difluoromethane (8-38 mass%), pentafluoroethane (5-35 mass%), and small amounts of 2,3,3,3-tetrafluoropropene and 1,1,1,2-tetrafluoroethane. This composite formulation combines the low GWP and non-flammability benefits of carbon dioxide with the low-temperature capabilities of fluorinated hydrocarbons, achieving temperatures down to -60°C while maintaining GWP below 150 and non-flammability (fire class A1).
Solution Approach 2:
The patent precisely controls the composition parameters of the refrigerant mixture, specifically maintaining carbon dioxide at 24-54 mass% and difluoromethane at 8-38 mass%, with controlled amounts of other components. This parameter optimization ensures the mixture achieves temperatures below -60°C while maintaining non-flammability and low GWP, resolving the contradiction between temperature achievement and safety properties.
2Temperature
If zeotropic refrigerant mixtures are used to achieve low temperatures, then temperature range is improved, but temperature stability deteriorates due to temperature glide requiring complex control systems
Solution Approach 1:
The patent optimizes the refrigerant composition parameters to achieve a temperature glide of 10.4 K to 31 K at evaporation pressures around 1 bar, which is a balanced compromise that allows adequate temperature range while minimizing the complexity of required control systems. The specific mass proportions of components are tuned to reduce temperature glide effects.
3Object-affected harmful factors
If high carbon dioxide concentration is used to ensure non-flammability, then flammability resistance is improved, but achievable temperature deteriorates due to freezing point limitation
Solution Approach 1:
The patent creates a composite refrigerant system where carbon dioxide (24-54 mass%) provides non-flammability and low GWP, while difluoromethane (8-38 mass%) and pentafluoroethane (5-35 mass%) extend the temperature range below -60°C. The synergistic combination allows the mixture to achieve temperatures down to -60°C while maintaining non-flammability, overcoming the limitation of pure carbon dioxide.
Solution Approach 2:
The patent assigns different functional roles to different components of the refrigerant mixture: carbon dioxide primarily provides non-flammability and low GWP, while the fluorinated hydrocarbons primarily provide low-temperature capability. This functional differentiation allows each component to optimize its local contribution to the overall system performance.
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 refrigerant mixture effectively reduces GWP and flammability, enabling the achievement of low temperatures while ensuring safety and cost-effective design of cooling circuits, particularly in test chambers, with improved temperature stability and reduced environmental impact.
Implementation Method 1
a refrigerant for a cooling device with a cooling circuit with at least one heat exchanger in which the refrigerant undergoes a phase change
Data Source
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Figure 5
AI summary
The invention relates to a refrigerant for a cooling device with a cooling circuit with at least one heat exchanger, the refrigerant undergoes a phase change in the heat exchanger, wherein the refrigerant is a refrigerant mixture consisting of a mass fraction of carbon dioxide (CO2), a mass fraction of difluoromethane (CH2F2) and a mass fraction of at least one further component, wherein the mass fraction of carbon dioxide in the refrigerant mixture is 9 to 75 mass percent, wherein the mass fraction of difluoromethane is up to 70 mass percent, and wherein the further component is 2,3,3,3-tetrafluoropropene (C3H2F4), wherein the mass fraction of 2,3,3,3-tetrafluoropropene is up to 47 mass percent.