Expansion valve control method for multi-connection air-conditioning system
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Solution Overview
Problem
Existing multi-connection air conditioning systems face challenges in accurately and timely detecting leakage in expansion valves, leading to issues like flood-back and compressor damage due to incomplete closing or improper opening of expansion valves during cooling and heating operations.
Innovation Solution
A method that determines the leakage condition of expansion valves by measuring temperature differences between indoor and pipeline temperatures, allowing for precise control of the expansion valve's opening degree and automatic repair operations to address leakage states, including mild, moderate, and severe leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the expansion valve is completely closed when the indoor unit is turned off during cooling operation, then refrigerant flow is stopped, but leakage causes flood-back and compressor damage
Solution Approach 1:
The system performs preliminary detection of expansion valve leakage by measuring temperature differences between pipelines before actual cooling operation begins. This early detection allows the system to identify potential leakage issues and take preventive measures, avoiding flood-back and compressor damage that would occur during actual operation.
Solution Approach 2:
The patent replaces direct mechanical monitoring of valve closure with a thermal field-based detection method. By measuring temperature differences in the refrigerant pipelines, the system can indirectly determine whether the expansion valve is properly closed, substituting mechanical observation with thermal sensing.
2Reliability
If the expansion valve maintains a small opening degree during heating operation, then refrigerant flow is controlled, but leakage causes poor heating effect and abnormal pressure
Solution Approach 1:
The system performs preliminary detection of expansion valve leakage by measuring temperature differences between pipelines before actual heating operation begins. This early detection allows the system to identify potential leakage issues and take preventive measures, avoiding poor heating effect and abnormal pressure that would occur during actual operation.
Solution Approach 2:
The system uses temperature difference measurements to provide feedback on the expansion valve's closure status. This feedback mechanism allows the control system to determine whether the valve is properly closed and take appropriate actions to prevent heating performance degradation and pressure abnormalities.
3Measurement precision
If temperature difference detection is used to identify leakage, then leakage can be detected, but the detection method must distinguish between normal and abnormal temperature differences
Solution Approach 1:
The patent changes the detection parameter from direct valve position monitoring to temperature difference measurement. By measuring the temperature difference between the first and second pipelines, the system can detect leakage based on thermal characteristics rather than mechanical position, simplifying the detection mechanism while maintaining accuracy.
Solution Approach 2:
The system applies different temperature comparison criteria for different operational contexts. It compares temperatures at specific locations in the refrigerant circuit and uses context-aware thresholding to distinguish between normal temperature variations and actual leakage conditions, enabling accurate detection without excessive complexity.
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 enables timely and accurate detection of expansion valve leakage, preventing system failures, ensuring proper operation, and maintaining user experience by effectively controlling the expansion valve's opening degree and performing automatic repairs.
Implementation Method 1
obtaining a temperature of the first pipeline of the indoor unit and a temperature of the second pipeline of the indoor unit when the indoor unit is in a turned-off state; and determining a leakage condition of an expansion valve of the indoor unit according to the indoor temperature of the environment in which the indoor unit is located, the temperature of the first pipeline of the indoor unit, and the temperature of the second pipeline of the indoor unit
Data Source
AI summary
An expansion valve control method for a multi-split air-conditioning system to solve the problem of detecting leakage of an expansion valve of a multi-split air-conditioning system. The system includes an outdoor unit and a plurality of indoor units connected to the outdoor unit, each of the indoor units is connected to the outdoor unit by a first pipeline and a second pipeline. The expansion valve control method includes acquiring an indoor temperature of an environment where an indoor unit is located; acquiring the temperature of a first pipeline of the indoor unit and the temperature of a second pipeline of the indoor unit when the indoor unit is in a shutdown state; and according to at least the indoor temperature of the environment where the indoor unit is located, determining the leakage condition of an expansion valve of the indoor unit.