CO2 Refrigeration System Gas Return Valve Control
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Solution Overview
Problem
Existing refrigeration systems using carbon dioxide (R744) as a natural refrigerant face efficiency issues in air conditioning temperature zones, and combining refrigeration and freezing equipment into a single circuit increases safety risks due to larger refrigerant amounts, necessitating a more efficient and safer system design.
Innovation Solution
A refrigeration system with a refrigeration cycle circuit that includes a low-stage compressor, high-stage compressors, a gas-liquid separator, and heat exchangers, utilizing a gas refrigerant return pipe with an expansion valve to control refrigerant flow and pressure, allowing for efficient heating and cooling operations while using carbon dioxide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If carbon dioxide (R744) is used as a natural refrigerant in air conditioning temperature zones, then environmental preservation characteristics are improved, but system efficiency deteriorates
Solution Approach 1:
The patent applies parameter changes by introducing a gas refrigerant return expansion valve to control the return amount of gas refrigerant from the gas-liquid separator. This valve adjusts the opening degree to control refrigerant flow rate and pressure, optimizing the refrigerant parameters in the air conditioning temperature zone to improve system efficiency while maintaining environmental benefits of CO2 refrigerant
Solution Approach 2:
The gas refrigerant return expansion valve acts as an intermediary device between the gas-liquid separator and the high-stage compressor. It mediates the refrigerant flow by controlling the expansion and flow rate, creating optimal conditions for CO2 refrigerant to operate efficiently in air conditioning temperature zones
2Device complexity
If refrigeration and freezing equipment are combined into a single refrigerant circuit, then device complexity is reduced, but safety deteriorates due to larger refrigerant amounts
Solution Approach 1:
The patent applies segmentation by dividing the refrigerant circuit into distinct functional segments: a low-stage compressor for refrigeration and a high-stage compressor for freezing, with a gas-liquid separator that separates refrigerant flows. This segmentation allows different refrigerant amounts and pressures in different zones, maintaining safety while using a unified circuit configuration
Solution Approach 2:
The gas-liquid separator serves as an intermediary device that separates the refrigerant flow into different paths for refrigeration and freezing sections. It mediates between the single circuit configuration and safety requirements by controlling where refrigerant goes based on temperature and pressure conditions
3Stress or pressure
If the opening degree of the gas refrigerant return expansion valve is controlled, then refrigerant pressure control is improved, but device complexity increases
Solution Approach 1:
The gas refrigerant return expansion valve is designed to automatically adjust its opening degree based on refrigerant flow conditions and pressure differential. The valve performs self-service by using the refrigerant flow itself to control the opening, eliminating the need for complex external control mechanisms while maintaining precise pressure control
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 system enhances the efficiency of air conditioning temperature zones using carbon dioxide by controlling refrigerant pressure and flow, ensuring stable operation and effective heat utilization, thereby improving energy efficiency and safety.
Implementation Method 1
a gas refrigerant return expansion valve that controls a return amount of the gas refrigerant from the gas-liquid separator
Implementation Method 2
an outdoor heat exchanger, and a gas-liquid separator, an indoor unit including an indoor heat exchanger
Implementation Method 3
the plurality of compressors includes a low-stage compressor and a high-stage compressor
Data Source
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AI summary
The present disclosure provides a refrigeration system capable of improving efficiency of an air conditioning temperature zone using carbon dioxide (R744), a natural refrigerant. The refrigeration system includes a refrigeration cycle circuit that connects an outdoor unit 10 including a low-stage compressor 11, a high-stage compressor 12, an outdoor heat exchanger 15, and a gas-liquid separator 16, an indoor unit 20 including an indoor heat exchanger 22, and a refrigeration-facility unit 30 including a refrigeration-facility heat exchanger 31, a gas refrigerant return pipe 60 is provided to send a gas refrigerant from the gas-liquid separator 16 to the high-stage compressor 12, and the gas refrigerant return pipe 60 is provided with a gas refrigerant return expansion valve 61 that controls a return amount of the gas refrigerant from the gas-liquid separator 16.