Compression cooling system and method for regulating a compression cooling system
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Solution Overview
Problem
In compression refrigeration systems, the lubricating properties of oil can be compromised when the compressor starts, leading to refrigerant condensation and reduced system performance, as existing methods like electrical preheating are costly and inefficient.
Innovation Solution
A method that involves monitoring the oil sump temperature and rapidly heating it by adjusting the compressor speed and superheat setpoint to prevent refrigerant condensation, using a control unit to detect overheating and regulate the throttle element, thereby maintaining oil lubrication without the need for electrical preheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrical preheating is used to heat the oil sump, then the oil lubrication is maintained, but the energy consumption and cost increase
Solution Approach 1:
The system uses the refrigerant itself to heat the oil sump during compressor startup, eliminating the need for external electrical preheating. The refrigerant's heat is transferred to the oil through the oil sump, maintaining lubrication properties using the system's own operational resources.
Solution Approach 2:
The patent introduces an intermediary heat transfer mechanism where the refrigerant acts as a medium to transfer thermal energy to the oil sump. This indirect heating method replaces direct electrical heating, reducing energy consumption while maintaining oil temperature and lubrication effectiveness.
2Use of energy by moving object
If the compressor starts immediately without preheating, then the energy consumption is reduced, but refrigerant condensation occurs and lubrication properties deteriorate
Solution Approach 1:
The system performs preliminary heating of the oil sump using refrigerant heat during the startup phase before full compression begins. This preliminary action prepares the oil for proper lubrication without requiring separate preheating equipment, enabling immediate safe operation.
Solution Approach 2:
The patent converts the refrigerant's thermal energy, which would otherwise be wasted during startup, into a useful heating source for the oil sump. By utilizing the refrigerant's heat that would naturally be present during system startup, the invention transforms a potentially harmful cold start condition into a beneficial preheating opportunity.
3Loss of time
If the oil sump is heated rapidly using traditional methods, then the heating time is reduced, but the system complexity and cost increase
Solution Approach 1:
The refrigerant circulation system serves multiple functions: cooling during operation, heating the oil sump during startup, and transferring thermal energy. This multi-functionality eliminates the need for separate heating devices, reducing system complexity while achieving rapid oil sump heating during compressor startup.
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 approach ensures minimal refrigerant condensation upon startup, maintains oil lubrication, and enhances system performance by reducing heating time and energy consumption.
Implementation Method 1
The low-pressure refrigerant evaporates in the evaporator by absorbing source heat
Implementation Method 2
The refrigerant is forced through the condenser, where it transfers heat to a heating medium located in a heat sink system
Implementation Method 3
Internal heat is transferred in an internal heat exchanger, for example, in the form of a recuperator, between the refrigerant flowing at high pressure from the condenser to the expansion valve and the refrigerant flowing at low pressure from the evaporator to the compressor
Data Source
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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 an oil sump temperature situation critical for the operation of the compressor as a function of an operating point of the compression refrigeration system and carrying out rapid oil sump heating by temporarily or permanently increasing a setpoint for the superheat (TÜE) of the refrigerant at the inlet to the compressor (210) and/or a speed of the compressor in the event of a critical oil sump temperature situation.