Compressor Liquid Level Control Using Isolation Resistance
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Solution Overview
Problem
High liquid levels within HVACR system compressors can cause system faults, leading to downtime and operational inefficiencies.
Innovation Solution
A method and system for controlling liquid levels within compressors by monitoring the isolation resistance of the compressor, using a sensor to measure the resistance between a power unit and the outer shell, and activating a heating element to evaporate refrigerant when the resistance falls below a predetermined threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid level in compressor is not monitored and controlled, then system operation continues without intervention, but compressor faults occur due to high liquid levels causing downtime
Solution Approach 1:
The isolation resistance sensor monitors liquid levels before they reach dangerous levels that would cause compressor faults. By detecting changes in isolation resistance between the power unit and outer shell, the system takes preliminary action to identify high liquid levels before they result in compressor damage or system shutdown, thereby preventing faults and reducing downtime
Solution Approach 2:
The system continuously monitors isolation resistance and provides feedback to the control unit. When the isolation resistance falls below a predetermined threshold indicating high liquid levels, the control unit activates the heating element to evaporate excess refrigerant, lowering the liquid level back to safe operating conditions. This closed-loop feedback mechanism maintains compressor reliability and prevents faults
2Reliability
If heating element is activated to evaporate refrigerant and lower liquid level, then liquid level is controlled to prevent faults, but energy is consumed by the heating element
Solution Approach 1:
The heating element is activated periodically only when the isolation resistance sensor detects that liquid levels have risen above the predetermined threshold. The control unit cycles the heating element on and off based on real-time isolation resistance measurements, activating it only during periods when liquid level reduction is needed rather than continuous operation, thereby managing energy consumption while maintaining compressor reliability
Solution Approach 2:
The system changes the operational parameters of the heating element based on isolation resistance measurements. When isolation resistance indicates high liquid levels, the heating element is activated with specific power levels to evaporate refrigerant. As liquid levels decrease and isolation resistance returns to normal ranges, the heating element parameters are adjusted or shut off, optimizing energy usage while ensuring compressor reliability
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 effectively reduces the risk of compressor faults by accurately determining liquid levels and automatically adjusting them to prevent faults, thereby minimizing downtime and improving system reliability.
Implementation Method 1
Activating the heating element causes the refrigerant mixed within the oil to evaporate, which in turn effectively lowers the liquid level within the compressor
Data Source
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AI summary
Sensor (240) for measuring the isolation resistance of an enclosure (202) of a compressor. The sensor can be electronically coupled to a controller (280) that is configured to activate a heating element (260) mechanically coupled to the enclosure when the controller determines that the isolation resistance measured by the sensor indicates that the compressor is at risk of faulting. Activating the heating element causes the refrigerant mixed within the oil to evaporate, which lowers the liquid level within the compressor.