CO2 Refrigerant Mixture for Ultra-Low Temperature Test Chambers
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Solution Overview
Problem
Current refrigerants with low global warming potential (GWP) and non-flammability cannot reach temperatures below -57°C in environmentally controlled test chambers, and existing solutions either have high GWP or risk freezing in refrigeration device circuits, posing challenges for maintaining low temperatures and safety in such chambers.
Innovation Solution
A refrigerant gas mixture comprising at least carbon dioxide, 1,1,1,2-tetrafluoroethane, and difluoromethane, with carbon dioxide at a mass percentage between 50% to 75%, specifically 69%, and 1,1,2-tetrafluoroethane and difluoromethane at 19% and 12% respectively, ensuring non-flammability and low GWP, capable of reaching temperatures below -57°C without modifying existing refrigeration devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If refrigerants with low GWP and non-flammability are used, then environmental safety and operational safety are improved, but the ability to reach temperatures below -57°C deteriorates
Solution Approach 1:
The patent changes the compositional parameters of the refrigerant mixture by incorporating carbon dioxide at specific concentrations (5-50% by mass) combined with other refrigerants like R134a and R32. This parameter adjustment allows the mixture to achieve both low GWP (<150), non-flammability, and the capability to reach temperatures below -57°C, thereby resolving the contradiction between safety and temperature performance
Solution Approach 2:
The patent creates a composite refrigerant mixture combining carbon dioxide with other refrigerant compounds (R134a, R32, or R125) in specific proportions. This composite approach leverages the non-flammable and low-GWP properties of CO2 while supplementing it with components that enhance low-temperature performance, thus achieving both safety requirements and temperature capabilities below -57°C
2Reliability
If carbon dioxide percentage is increased to achieve low GWP and non-flammability, then environmental safety and temperature reachability are improved, but the risk of freezing in refrigeration device circuits increases
Solution Approach 1:
The patent optimizes the concentration parameter of carbon dioxide within a specific range (5-50% by mass) rather than using high concentrations. This parameter control ensures that the refrigerant mixture maintains low GWP and non-flammability while avoiding excessive CO2 levels that would cause circuit freezing, thus resolving the contradiction between safety/temperature performance and freezing risk
Solution Approach 2:
The patent introduces intermediary refrigerant components (R134a, R32, or R125) that act as mediators between carbon dioxide and the system components. These intermediary substances modify the mixture's properties to reduce the freezing risk in circuits while preserving the low-GWP and non-flammable characteristics, and maintaining the ability to reach temperatures below -57°C
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 temperatures below -57°C while maintaining a low GWP and non-flammability, overcoming previous limitations by using a higher carbon dioxide percentage that was thought to be harmful, and successfully replacing refrigerants that cannot achieve such low temperatures, ensuring safe and efficient operation in environmentally controlled test chambers.
Implementation Method 1
a refrigerant for a refrigeration device, comprising a gas mixture, said gas mixture comprising at least carbon dioxide, 1,1,1,2-tetrafluoroethane and difluoromethane
Data Source
Figure 1
AI summary
Refrigerant for a refrigeration device (1) comprising a gas mixture, said gas mixture comprising at least carbon dioxide, 1,1,1,2-tetrafiuoroethane and difluoromethane, characterised in that carbon dioxide has a mass percentage higher than 50 % in relation to the total mixture.