Heat Pump Refrigerant Leakage Detection Using Pump-Down Operation
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Solution Overview
Problem
Existing heat pump systems lack the capability for timely determination of refrigerant leakage, as previous methods rely on schedules or superheat changes without specifying timing, leading to inadequate detection of leakage occurrence or non-occurrence.
Innovation Solution
Incorporating a supercooling heat exchanger in the refrigerant path from the receiver to the compressor's suction side, allowing the system to determine refrigerant leakage after a predetermined time has passed since the pump-down operation started, utilizing the control device to assess the degree of superheat and determine leakage based on set criteria.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If refrigerant leakage detection is performed based on detection schedule or superheat changes, then the system can monitor refrigerant status, but the determination of refrigerant leakage cannot be made timely
Solution Approach 1:
The system performs a pump-down operation before leakage detection to preliminarily concentrate any leaked refrigerant into the receiver. This preliminary action ensures that when detection is performed, any leakage will be evident through the receiver level measurement, enabling timely and accurate detection without requiring continuous monitoring during operation
Solution Approach 2:
The system uses its own operational cycle (pump-down operation) to facilitate the detection process. By utilizing the existing compression and refrigerant circulation system, the patent eliminates the need for separate detection equipment or complex additional sensors, allowing the system to self-diagnose leakage conditions
2Measurement precision
If additional sensors are installed to detect refrigerant leakage, then detection accuracy improves, but device complexity increases
Solution Approach 1:
The system uses its own operational cycle (pump-down operation) to facilitate the detection process. By utilizing the existing compression and refrigerant circulation system, the patent eliminates the need for separate detection equipment or complex additional sensors, allowing the system to self-diagnose leakage conditions
Solution Approach 2:
The patent detects leakage by measuring changes in receiver refrigerant level rather than using traditional temperature or pressure sensors. This parameter change approach uses the existing level measurement capability to detect leakage, avoiding the need for additional specialized sensors while maintaining high detection accuracy
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 timely and accurate detection of refrigerant leakage, improving the precision and reliability of leakage determination without the need for additional sensors, by waiting for the refrigerant to stabilize and flow out, thus ensuring the system's operational integrity.
Implementation Method 1
a supercooling heat exchanger is provided in a refrigerant path from a predetermined position in the receiver to the suction side of the compressor
Data Source
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AI summary
A heat pump has a compressor, a heat source-side heat exchanger, a receiver, at least one expansion valve, and a utilization-side heat exchanger, and is configured to perform a pump-down operation for recovering a liquid refrigerant into the receiver during a predetermined stopping time. The heat pump is configured to determine whether refrigerant leakage has occurred or not, by detecting an amount of the liquid refrigerant in the receiver in the pump-down operation.