Cooling system with low temperature load
Find Innovative SolutionsGenerate Solutions
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 control system that includes a temperature sensor, pressure sensor, pulse valve, flash gas bypass valve, and controller, which mixes liquid refrigerant from a flash tank with refrigerant from a low temperature compressor to reduce the temperature and pressure before it reaches the medium temperature compressor, ensuring safe operation by regulating the refrigerant through a liquid injection line and flash gas bypass line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the medium temperature load is not present in a CO2 booster system, then the system structure is simplified and operation is more flexible, but the refrigerant temperature becomes too high for the medium temperature compressor to handle safely
Solution Approach 1:
The patent introduces a flash tank as an intermediary component between the low temperature compressor and medium temperature compressor. The flash tank separates the refrigerant into liquid and vapor phases, with the liquid portion being redirected to cool the compressor suction line. This intermediary device enables safe operation without medium temperature load by mediating the temperature of the refrigerant entering the medium temperature compressor.
Solution Approach 2:
The patent extracts the liquid refrigerant portion from the main refrigerant flow using the flash tank separation. By taking out the liquid phase and redirecting it through the liquid injection line to cool the suction line, the system removes the harmful high temperature effect while maintaining the beneficial cooling function. This extraction allows the medium temperature compressor to receive refrigerant at safe temperatures even when no medium temperature load is present.
2Reliability
If liquid refrigerant is injected into the refrigerant line to reduce temperature, then the medium temperature compressor can operate safely, but the system complexity increases with additional valves and control mechanisms
Solution Approach 1:
The system uses the flash tank's natural phase separation property to automatically generate the cooling effect. The flash tank inherently separates liquid and vapor refrigerant based on density differences, requiring no additional active control for the separation process. The liquid injection valve simply needs to modulate the already-separated liquid refrigerant, rather than requiring a complex active cooling system. This self-service approach reduces control complexity while maintaining safety.
Solution Approach 2:
The patent exploits the phase transition of refrigerant in the flash tank, where high-pressure liquid refrigerant flashes into a mixture of liquid and vapor at lower pressure. This natural phase transition provides the separated liquid refrigerant needed for cooling without requiring mechanical separation devices. The phase transition automatically occurs based on pressure differential, simplifying the control mechanism needed to achieve safe compressor operation.
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 the medium temperature compressor to operate safely even without a medium temperature load, preventing damage and ensuring continuous operation by effectively cooling the refrigerant before it is compressed.
Implementation Method 1
mixes liquid refrigerant from a flash tank with refrigerant from a low temperature compressor to reduce the temperature and pressure
Implementation Method 2
mixes liquid refrigerant from a flash tank with refrigerant from a low temperature compressor to reduce the temperature and pressure
Implementation Method 3
liquid refrigerant from a flash tank
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A system (100) includes a temperature sensor (215), a pressure sensor (220), and a controller (210). The temperature sensor (215) measures a temperature of a refrigerant at a compressor (145). The compressor (145) receives the refrigerant from a second compressor (140). The pressure sensor (220) measures a pressure of the refrigerant at the compressor (145). The controller (210) 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 (210) actuates a pulse valve (205) coupled to a liquid injection line (200). The pulse valve (205) controls the flow of a liquid refrigerant from a flash tank (115) through the liquid injection line (200) to mix with the refrigerant at the compressor (145).