CO2 Booster Compressor Cooling via Flash Tank Liquid Injection
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Solution Overview
Problem
In CO2 booster refrigeration systems, the absence of a medium temperature load can result in refrigerant temperatures being too high for medium temperature compressors to handle safely, leading to unsafe operating conditions.
Innovation Solution
A system comprising a temperature sensor, pressure sensor, and controller that actuates a pulse valve to mix liquid refrigerant from a flash tank with the refrigerant before it enters the medium temperature compressor, regulating the temperature and pressure to ensure safe operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the medium temperature load is not present in the CO2 booster system, then the system operates with reduced complexity, but the refrigerant temperature becomes too high for the medium temperature compressor to handle safely
Solution Approach 1:
A liquid injection line with a pulse valve is introduced as an intermediary component between the flash tank and the medium temperature compressor. This intermediary injects liquid refrigerant into the suction line to cool the refrigerant vapor, mediating the temperature issue caused by the absent medium temperature load without requiring structural changes to the compressor itself.
Solution Approach 2:
The system changes the temperature parameter of the refrigerant entering the medium temperature compressor by injecting liquid refrigerant from the flash tank. This parameter change is controlled by the pulse valve which modulates the liquid refrigerant flow based on temperature and pressure feedback from sensors, dynamically adjusting the cooling effect to maintain safe operating conditions.
2Temperature
If liquid refrigerant is injected to cool the refrigerant, then the refrigerant temperature decreases to safe levels, but the system complexity increases due to additional components
Solution Approach 1:
The liquid injection line serves multiple functions: it cools the refrigerant vapor, controls suction superheat, and provides a safety mechanism for compressor operation. The pulse valve integrates temperature and pressure sensing capabilities, combining multiple control functions in a single component that responds to system conditions automatically.
Solution Approach 2:
The system uses its own flash tank and liquid refrigerant supply to cool the refrigerant entering the medium temperature compressor. The pulse valve automatically modulates based on feedback from temperature and pressure sensors, creating a self-regulating system that adjusts liquid injection without external intervention, making the system self-service for its own cooling needs.
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 configuration allows for the safe operation of medium temperature compressors even without a medium temperature load by cooling the refrigerant with liquid and flash gas from the flash tank, preventing compressor failure and ensuring system safety.
Implementation Method 1
mixing liquid refrigerant from a flash tank with a refrigerant going into a medium temperature compressor reduces the temperature of the refrigerant
Implementation Method 2
a high side heat exchanger that removes heat from the refrigerant
Data Source
AI summary
A system includes a temperature sensor, a pressure sensor, and a controller. The temperature sensor measures a temperature of a refrigerant at a compressor. The compressor receives the refrigerant from a second compressor. The pressure sensor measures a pressure of the refrigerant at the compressor. The controller receives one or more of the measured temperature and the measured pressure and determines that one or more of the measured temperature and the measured pressure exceed a threshold. In response to that determination, the controller actuates a pulse valve coupled to a liquid injection line. The pulse valve controls the flow of a liquid refrigerant from a flash tank through the liquid injection line to mix with the refrigerant at the compressor.