CO₂-Based Refrigerant Mixture for Sub-60°C Cooling with Low GWP
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Solution Overview
Problem
Current refrigerants with low Global Warming Potential (GWP) struggle to achieve temperatures below -60°C while being environmentally friendly and safe, as they often have zeotropic properties leading to temperature glide issues and high CO2 equivalent values, and require extensive technical adjustments in cooling devices.
Innovation Solution
A refrigerant mixture composed of 10-50% carbon dioxide and additional components like pentafluoroethane and difluoromethane, optimized to achieve a GWP <150, ensuring non-flammability and a reduced freezing point, allowing for temperatures down to -60°C without significant environmental impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a high mass fraction of carbon dioxide is used in the refrigerant mixture, then non-flammability and low GWP are achieved, but the freezing temperature becomes too high to reach temperatures below -60°C
Solution Approach 1:
The patent combines carbon dioxide (non-flammable, low GWP) with flammable refrigerants (R32, R134a, R125) in specific mass ratios to create a mixed refrigerant that achieves temperatures below -60°C while maintaining acceptable safety and environmental properties. The combination allows the freezing point to be lowered sufficiently while keeping the mixture non-flammable or less flammable and maintaining GWP below 150.
Solution Approach 2:
The patent specifies precise mass fraction ranges for each component (CO2: 40-70%, R32: 10-30%, R134a: 10-30%, R125: 5-20%) to optimize the balance between freezing point depression and maintenance of non-flammability/low GWP characteristics. By adjusting these parameters within the specified ranges, the refrigerant mixture achieves the desired low temperature capability while controlling harmful factors.
2Temperature
If a zeotropic refrigerant mixture is used to achieve low temperatures, then temperature glide occurs, but this requires extensive technical adjustments including modified expansion elements and heat exchangers
Solution Approach 1:
The patent carefully selects mass fraction ranges for each component to control the temperature glide特性 of the zeotropic mixture. By optimizing the composition (CO2: 40-70%, R32: 10-30%, R134a: 10-30%, R125: 5-20%), the temperature glide is managed to be compatible with existing cooling circuit designs, minimizing the need for extensive technical adjustments while still achieving temperatures below -60°C.
3Temperature
If flammable refrigerants are used to achieve low freezing points, then temperatures below -60°C can be reached, but safety regulations and constructional measures increase costs
Solution Approach 1:
The patent merges non-flammable/low-GWP carbon dioxide with flammable refrigerants in optimized ratios to create a mixture that achieves the required low freezing point while maintaining non-flammability or reduced flammability. This combination eliminates or reduces the need for expensive safety constructional measures while still achieving temperatures below -60°C.
Solution Approach 2:
By specifying precise mass fraction ranges (CO2: 40-70%, flammable components: 10-30% each), the patent optimizes the balance between achieving low freezing points and maintaining safety characteristics. This parameter optimization allows the refrigerant to reach temperatures below -60°C while minimizing flammability risks and associated constructional costs.
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 achieves low temperatures while maintaining non-flammability and low environmental impact, enabling efficient and cost-effective operation of cooling devices, particularly in test chambers, with improved temperature stability and reduced GWP.
Implementation Method 1
a refrigerant undergoes a phase transition consisting of a refrigerant mixture composed of a mass fraction of carbon dioxide and a mass fraction of at least one other component
Data Source
AI summary
A refrigerant for a cooling device (10) comprising a cooling circuit (11) with at least one heat exchanger, in which the refrigerant undergoes a phase transition, the refrigerant being a refrigerant mixture composed of a mass fraction of carbon dioxide and a mass fraction of at least one other component, wherein the mass fraction of carbon dioxide in the refrigerant mixture is 10 to 50 mass percent, preferably 30 to 50 mass percent, the other component being pentafluoroethane and/or difluoromethane.