Refrigeration system and control method for starting refrigeration system
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Solution Overview
Problem
Refrigeration systems face high starting loads due to increasing suction and exhaust pressures with ambient temperature, leading to potential start failures and excessive engine size requirements, especially in regions with large temperature differences, and result in lubricating oil being carried away from the compressor during shutdown.
Innovation Solution
Incorporating a first one-way valve between the throttle element and condenser, and a suction pressure adjustment valve near the compressor's suction port to isolate the suction and exhaust sides from the evaporator or reservoir, creating a closed section with only vapor-phase refrigerant during shutdown, reducing starting load and preventing oil carryover.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the refrigeration system operates in high ambient temperature environments, then the cooling effect is maintained, but the starting load increases excessively due to increased suction and exhaust pressures
Solution Approach 1:
The refrigeration system is segmented into two independent sections: a first section containing the compressor, condenser, and throttle element, and a second section containing the evaporator. The one-way valve creates a segmentation point that allows the first section to be isolated from the second section during shutdown, enabling independent pressure management in each section and reducing the starting load on the compressor.
Solution Approach 2:
The harmful factor (high pressure in the evaporator section) is extracted and isolated from the compressor section using the one-way valve. By preventing refrigerant flow from the evaporator to the compressor during shutdown, the high pressure in the evaporator section does not contribute to the starting load, effectively removing the adverse effect.
2Reliability
If the refrigeration system is designed to handle extreme temperature differences, then the system operates reliably in regions like the Middle East, but lubricating oil is carried out of the compressor during shutdown, leading to greater friction during start
Solution Approach 1:
The system is divided into isolated sections with the one-way valve creating a barrier that prevents refrigerant (and carried lubricating oil) from flowing from the evaporator back into the compressor during shutdown. This segmentation protects the compressor's lubrication system from oil depletion, ensuring reliable operation in extreme temperature conditions.
Solution Approach 2:
The one-way valve acts as an intermediary element that selectively allows refrigerant flow in one direction (during operation) while blocking reverse flow (during shutdown). This intermediary prevents the harmful carryover of lubricating oil into the evaporator section, protecting the compressor's lubrication system.
3Reliability
If a larger engine is selected to handle the high starting load, then the system can start reliably in high temperature conditions, but the engine size and cost increase excessively
Solution Approach 1:
The harmful factor (high pressure contribution from the evaporator section) is extracted and isolated using the one-way valve. This reduces the peak starting load to a level that can be handled by a smaller, more cost-effective engine while maintaining reliable operation in high temperature conditions.
Solution Approach 2:
The system changes the pressure parameter in the compressor's suction line by preventing high-pressure refrigerant from the evaporator from entering the compressor section during shutdown. This parameter change (reducing suction pressure) directly reduces the starting load, allowing for a smaller engine selection.
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 solution effectively reduces the starting load and power requirements of the refrigeration system, minimizing the need for large engines and preventing lubricating oil carryover, thereby ensuring reliable starts and optimizing engine power and size.
Implementation Method 1
a first one-way valve 192 is disposed between the throttle element 195 and the condenser 120
Implementation Method 2
a suction pressure adjustment valve 196 is disposed close to the suction port of the compressor 110
Data Source
Figure 1~2
Figure 3
AI summary
A refrigeration system and a start control method for a refrigeration system. The refrigeration system includes: a refrigeration loop having an exhaust port of a compressor, a condenser, a throttle element, an evaporator, and a suction port of the compressor connected in sequence by using a flow path; wherein a first valve is disposed between the throttle element and the condenser, and the first valve is at least capable of cutting off a refrigerant flow from the throttle element to the condenser; and a second valve is disposed close to the suction port of the compressor, and the second valve is used to control on/off of a flow path between the evaporator and the compressor. Starting load of the refrigeration system according to the present invention can be effectively reduced, so that the power and size of a drive component for providing power can also be reduced.