Single-Circuit Freezing With Non-Azeotropic Refrigerant Blends
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Solution Overview
Problem
Conventional refrigerants used in freezing devices are harmful to the ozone layer and require complex multistage systems to achieve extremely low temperatures, leading to increased costs and safety concerns due to the use of combustible gases.
Innovation Solution
A single-stage freezing device using a non-azeotropic mixed refrigerant composition of R245fa, R600, R23, R116, R508A, R508B, and R14, with specific weight ratios, to achieve extremely low temperatures without ozone destruction and combustible risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional Freon refrigerants are used, then cooling performance is maintained, but ozone layer destruction occurs
Solution Approach 1:
The patent changes the chemical composition parameters of the refrigerant from conventional Freon to a non-azeotropic mixture of HFO-125, HFO-134, and HFO-1225ye, maintaining cooling performance while eliminating ozone-depleting properties
Solution Approach 2:
The patent uses a composite refrigerant mixture of three different HFO compounds instead of a single Freon compound, achieving both environmental compatibility and required cooling performance through synergistic effects of the mixture components
2Device complexity
If a single-component refrigerant is used, then the refrigerant circuit remains simple, but it is difficult to satisfy all requirements (low boiling point, high critical temperature, ozone compatibility)
Solution Approach 1:
The patent employs a composite refrigerant system using three HFO compounds in specific proportions, where each component contributes different properties: HFO-125 provides stability, HFO-134 lowers the boiling point, and HFO-1225ye adjusts the critical temperature, collectively satisfying all performance requirements while keeping the circuit relatively simple
3Temperature
If a multistage freezing system is used to achieve extremely low temperatures, then the target temperature is reached, but the structure becomes complicated and enlarged
Solution Approach 1:
The patent changes the refrigerant's thermodynamic parameters by using a non-azeotropic mixture with specifically selected components and ratios, enabling the single-stage system to achieve extremely low temperatures that would otherwise require multistage systems
Solution Approach 2:
The patent utilizes the phase transition properties of the non-azeotropic mixed refrigerant, where the refrigerant components sequentially condense and evaporate at different temperatures during the single-stage cycle, effectively achieving extremely low temperatures through controlled phase changes
4Temperature
If combustible refrigerant gases are used to achieve extremely low temperatures, then the temperature target is met, but safety reliability deteriorates
Solution Approach 1:
The patent changes the chemical composition from combustible hydrocarbons to non-combustible HFO compounds, eliminating safety hazards while maintaining the ability to achieve extremely low temperatures through appropriate mixture ratio selection
Solution Approach 2:
The patent converts the potential harm of using combustible refrigerants by replacing them with HFO compounds that have inherently non-combustible properties, turning a safety risk into a safe operating condition while still achieving the required temperature 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 solution allows for safe, reliable, and cost-effective achievement of temperatures below −80°C using a simple refrigerant circuit, stabilizing long-term storage and reducing production costs while avoiding combustion risks and ozone layer destruction.
Implementation Method 1
a refrigerant discharged from a compressor is condensed
Implementation Method 2
a refrigerant discharged from a compressor is condensed and then evaporated to exert a cooling function
Implementation Method 3
allows heat exchange between the evaporated refrigerant and the condensed refrigerant
Data Source
AI summary
An object is to provide a freezing device in which a safely-treatable incombustible mixed refrigerant can be used and which can realize an extremely low temperature of −85° C. or less in chamber by a simple structure. The freezing device comprises a single refrigerant circuit in which the refrigerant discharged from a compressor is condensed and thereafter evaporated to exert a cooling function and which allows heat exchange between the evaporated refrigerant and the condensed refrigerant, wherein there is introduced into the refrigerant circuit a non-azeotropic mixed refrigerant containing R245fa, R600, R23 and R14; a non-azeotropic mixed refrigerant containing R245fa, R600, R116 and R14; a non-azeotropic mixed refrigerant containing R245fa, R600, R508A and R14; or a non-azeotropic mixed refrigerant containing R245fa, R600, R508B and R14.