Compressor Liquid Level Control Using Isolation Resistance Measurement
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Solution Overview
Problem
High liquid levels within compressors in HVACR systems can cause faults, leading to downtime and operational issues.
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 patent replaces complex mechanical liquid level sensing mechanisms with an electrical resistance measurement system. By measuring the isolation resistance between the power unit and outer shell, the system determines liquid levels through electrical properties rather than mechanical sensors, simplifying the overall device complexity while maintaining reliability.
Solution Approach 2:
The patent introduces an isolation resistance measurement as an intermediary parameter to indirectly detect liquid levels. Instead of directly monitoring liquid level, the system measures the resistance change caused by liquid presence, which then triggers appropriate control actions, simplifying the monitoring mechanism while ensuring compressor reliability.
2Reliability
If heating element is activated to evaporate refrigerant, then liquid level is reduced effectively, but energy consumption increases
Solution Approach 1:
The patent implements a feedback control system where the heating element is activated only when the isolation resistance measurement indicates high liquid levels. The system continuously monitors resistance and adjusts heating element operation accordingly, reducing energy consumption by activating the heater only when necessary to maintain compressor reliability.
Solution Approach 2:
The patent utilizes the phase transition of refrigerant from liquid to vapor through controlled heating. By activating the heating element, the system evaporates excess refrigerant liquid, effectively reducing liquid levels in the compressor. This phase change mechanism provides an efficient method to control liquid levels while managing energy consumption through targeted heating.
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 ensuring 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
Implementation Method 2
a sensor for measuring the isolation resistance of an enclosure (e.g., housing) of a compressor... a first terminal of the sensor is connected to a power terminal (e.g., a power unit) of the compressor while a second terminal of the sensor is grounded to an outer shell of the enclosure
Data Source
AI summary
Devices, systems, and methods are disclosed for reducing leakage current in compressors, such as for heating, ventilation, and air conditioning, and refrigeration (HVAC/HVACR) systems. Several embodiments include a sensor for measuring the isolation resistance of an enclosure of a compressor. The sensor can be electronically coupled to a controller that is configured to activate a heating element mechanically coupled to the enclosure when the controller determines that the isolation resistance measured by the sensor falls 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.