Refrigerating device and refrigerating device control method
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Solution Overview
Problem
Refrigeration cycle apparatuses using HFO-1123 refrigerant, which undergoes disproportionation, face challenges in safety, cost, operating efficiency, and global warming impact due to lack of established operating techniques.
Innovation Solution
Maintaining the low-stage refrigerant at a pressure lower than its disproportionation pressure, using refrigerant mixtures like HFO-1123 and HFO-1234yf, and controlling the high-stage compressor operation to prevent disproportionation, allowing the apparatus to operate as if the refrigerant does not undergo disproportionation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CO2 refrigerant is used as the low-stage refrigerant, then the pressure can be maintained at or below 7.4 MPa (critical pressure), but the COP of the theoretical cycle is lower compared to HFC-based refrigerants
Solution Approach 1:
The patent changes the refrigerant parameter from CO2 to HFO-1123, which has different thermodynamic properties including lower operating pressure and comparable or higher COP values. This parameter change allows the system to achieve both reliable pressure control and improved energy efficiency.
2Use of energy by moving object
If HFO-1123 refrigerant is used as the low-stage refrigerant, then the pressure range can be lowered and COP can be improved, but the refrigerant undergoes disproportionation which creates safety and operational challenges
Solution Approach 1:
The patent controls the operating pressure parameter to remain below the disproportionation pressure of HFO-1123 refrigerant. By maintaining pressure within this specific range, the system achieves high COP while preventing the harmful disproportionation reaction, ensuring operational stability.
Solution Approach 2:
The patent uses a refrigerant mixture where HFO-1123 is combined with other refrigerants in specific proportions. This mixture approach allows the system to benefit from HFO-1123's high COP while the other components suppress disproportionation, creating a stable long-term operating solution.
3Object-affected harmful factors
If HFO-1123 refrigerant is used as the low-stage refrigerant, then the global warming potential can be reduced, but the lack of established operating techniques creates uncertainty
Solution Approach 1:
The patent establishes specific operating parameters including pressure control below disproportionation pressure, temperature ranges, and pressure ratios that enable reliable operation of HFO-1123. These parameter specifications provide the missing operational guidelines, making the environmentally friendly refrigerant practical for real-world applications.
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
This approach enhances safety, reduces costs, improves energy-saving performance, and minimizes the apparatus's global warming effect by maintaining the low-stage refrigerant below its disproportionation pressure, achieving comparable COP to HFC-based refrigerants and lower GWP than CO2.
Implementation Method 1
a low-stage refrigeration cycle that includes a low-stage compressor, a low-stage condenser, a low-stage pressure reducing device, and a low-stage evaporator, and circulates low-stage refrigerant
Implementation Method 2
a low-stage refrigeration cycle that includes a low-stage compressor, a low-stage condenser, a low-stage pressure reducing device, and a low-stage evaporator
Implementation Method 3
a high-stage refrigeration cycle that includes a high-stage compressor, a high-stage condenser, a high-stage pressure reducing device, and a high-stage evaporator, and circulates high-stage refrigerant
Implementation Method 4
a high-stage refrigeration cycle that includes a high-stage compressor, a high-stage condenser, a high-stage pressure reducing device, and a high-stage evaporator
Implementation Method 5
a cascade condenser exchanging heat between the low-stage refrigerant in the low-stage condenser and the high-stage refrigerant in the high-stage evaporator
Implementation Method 6
a low-stage pressure reducing device, and a low-stage evaporator
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A refrigeration cycle apparatus 1 includes a low-stage refrigeration cycle 10 that includes a low-stage compressor 11, a low-stage condenser 12, a low-stage pressure reducing device, and a low-stage evaporator 14, and circulates low-stage refrigerant, a high-stage refrigeration cycle 30 that includes a high-stage compressor 31, a high-stage condenser 32, a high-stage pressure reducing device, and a high-stage evaporator 34, and circulates high-stage refrigerant, a cascade condenser 40 exchanging heat between the low-stage refrigerant in the low-stage condenser 12 and the high-stage refrigerant in the high-stage evaporator 34, and a controller 50. The low-stage refrigerant is a refrigerant that undergoes disproportionation. The low-stage refrigerant is maintained at a pressure lower than a disproportionation pressure at which the low-stage refrigerant undergoes disproportionation.