Compression cooling system and method for operating a compression cooling system
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Solution Overview
Problem
Existing compression refrigeration systems face challenges in achieving efficient operation while ensuring the protection of compressor components from overheating, which can lead to inefficiencies and potential damage.
Innovation Solution
A method and system that control the throttle device based on detecting overheating as the difference between dew point temperature and refrigerant temperature, setting two target superheats to maximize efficiency and maintain safe compressor temperatures, using a refrigeration model and actual hot gas temperature for adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the refrigerant superheat is increased to maximize system efficiency, then the system efficiency improves, but the compressor outlet temperature increases causing overheating risk
Solution Approach 1:
The control unit dynamically adjusts the target superheat parameter based on detected compressor outlet temperature. When overheating is detected, the target superheat is reduced to lower the compressor outlet temperature. This parameter adaptation resolves the contradiction by allowing high efficiency operation under normal conditions while preventing overheating when temperature limits are approached.
Solution Approach 2:
The system implements a feedback control mechanism where the control unit continuously detects the compressor outlet temperature and adjusts the target superheat accordingly. The detected temperature feeds back to modify the superheat setpoint, creating a closed-loop control that balances efficiency and temperature protection.
2Reliability
If the target superheat is reduced to prevent compressor overheating, then the compressor temperature safety improves, but the system efficiency decreases
Solution Approach 1:
The control unit dynamically modifies the target superheat parameter based on actual compressor outlet temperature detection. When the temperature approaches unsafe levels, the target superheat is reduced to ensure compressor safety. This dynamic parameter adjustment maintains reliability while minimizing efficiency loss by only reducing superheat when necessary.
Solution Approach 2:
The system transitions from static superheat control to dynamic superheat control, where the target superheat continuously adapts to changing operating conditions. This dynamic adjustment allows the system to maintain optimal efficiency under normal conditions while automatically reducing superheat to protect the compressor when temperature limits are approached.
3Device complexity
If a single target superheat value is used for all operating conditions, then the control system is simple, but the system cannot adapt to varying efficiency and temperature requirements
Solution Approach 1:
The control system transitions from a static single target superheat value to a dynamic adaptive control mechanism. The control unit continuously detects operating conditions and adjusts the target superheat accordingly, enabling the system to adapt to varying efficiency and temperature requirements while maintaining relatively simple control logic.
Solution Approach 2:
The system implements parameter adaptation by dynamically changing the target superheat value based on detected operating conditions. This allows the control system to optimize performance across different operating scenarios without requiring complex control algorithms, maintaining simplicity while enhancing adaptability.
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
Enables efficient operation of compression refrigeration systems by maintaining optimal superheat levels and preventing compressor overheating, ensuring component safety and enhancing overall system performance.
Implementation Method 1
an internal heat exchanger for transferring thermal energy of the refrigerant before entering the throttle element to the refrigerant before entering the compressor
Implementation Method 2
The low-pressure refrigerant evaporates in the evaporator by absorbing source heat
Implementation Method 3
The low-pressure refrigerant evaporates in the evaporator by absorbing source heat
Implementation Method 4
a gaseous refrigerant is compressed from a low pressure to a high pressure by a compressor
Implementation Method 5
The refrigerant is forced through the condenser, where it transfers heat to a heating medium located in a heat sink system
Implementation Method 6
The refrigerant is forced through the condenser, where it transfers heat to a heating medium located in a heat sink system
Data Source
Figure 1
Figure 2
AI summary
The present invention relates to a method for controlling a compression refrigeration system (200) and an associated compression refrigeration system (200). The method comprises the following steps: determining a first target superheat of the refrigerant at the inlet to the compressor, wherein the first target superheat, as a function of an operating point of the compression refrigeration system, maximizes the efficiency of the compression refrigeration system; determining a second target superheat of the refrigerant at the inlet to the compressor based on a maximum permissible hot gas temperature at the outlet of the compressor; and controlling the throttling device (230) based on the lower of the first target superheat and the second target superheat values.