Refrigeration Compressor Diagnostics Using Current and Liquid-Line Temperature
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Solution Overview
Problem
Conventional compressor protection systems in refrigeration systems require multiple sensors to accurately diagnose faults, leading to frequent shutdowns and inefficient repairs due to their inability to precisely indicate specific faults without a plurality of sensors.
Innovation Solution
A diagnostic system that includes a liquid-line temperature sensor and processing circuitry to determine condenser temperature and subcooling values using a compressor map, allowing for the diagnosis of faults without the need for individual sensors for each operating parameter, thereby reducing system complexity and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple sensors are used to measure and monitor various system and compressor operating parameters, then measurement precision and fault diagnosis accuracy are improved, but device complexity increases
Solution Approach 1:
The patent applies multi-functionality by enabling a single sensor to measure multiple operating parameters (temperature, pressure, humidity) and by designing the control unit to perform multiple functions: data acquisition, parameter calculation, fault diagnosis, and protection control. This eliminates the need for separate sensors for each parameter while maintaining comprehensive monitoring capabilities.
Solution Approach 2:
The patent combines multiple sensing functions into a single integrated sensor unit and merges the control unit's functions into a unified system. The control unit integrates data processing, parameter calculation, and fault diagnosis capabilities that would traditionally require separate devices, thereby reducing system complexity while preserving measurement precision.
2Reliability
If conventional protection systems shut down the compressor when fault conditions are detected, then compressor and system protection is improved, but productivity decreases due to frequent shutdowns and service calls
Solution Approach 1:
The patent implements continuous feedback monitoring of operating parameters with real-time fault diagnosis. The control unit continuously compares measured parameters against predetermined ranges and provides immediate feedback on system status, enabling early detection and diagnosis of faults before they cause damage, thus maintaining operational continuity while ensuring protection.
Solution Approach 2:
The system performs preliminary fault diagnosis and identification before actual damage occurs. By continuously monitoring parameters and detecting anomalies early, the system can alert operators to potential issues and take preventive actions, avoiding unexpected shutdowns and maintaining productivity while still protecting the compressor.
3Loss of information
If a plurality of sensors are employed to diagnose compressor faults, then measurement coverage is improved, but ease of repair worsens due to increased diagnostic complexity
Solution Approach 1:
The control unit serves as an intermediary that processes data from sensors and translates raw measurements into meaningful diagnostic information. It automatically calculates operating parameters, compares them against predetermined ranges, and identifies specific fault conditions, thereby maintaining comprehensive parameter monitoring while simplifying the diagnostic process for technicians.
Solution Approach 2:
The patent replaces manual diagnostic procedures with automated electronic control and processing. The control unit automatically performs parameter calculations, fault analysis, and diagnosis that would traditionally require manual intervention and complex mechanical diagnostic tools, thereby maintaining comprehensive monitoring coverage while significantly easing repair and diagnosis.
Data Source
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AI summary
A system includes a compressor and a compressor motor functioning in a refrigeration circuit. A sensor produces a signal indicative of one of current and power drawn by the motor and a liquid-line temperature sensor provides a signal indicative of a temperature of liquid circulating within the refrigeration circuit. Processing circuitry processes the current or power signal to determine a condenser temperature of the refrigeration circuit and a subcooling value of the refrigeration circuit from the condenser temperature and the liquid-line temperature signal.