Expansion valve control method for multi-split 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, compressor damage, and poor heating performance due to incomplete valve closure or opening.
Innovation Solution
A method that determines the leakage condition of expansion valves in multi-connection air conditioning systems by analyzing temperature differences between indoor and pipeline temperatures, allowing for precise control of the expansion valve opening degrees to address leakage states, including mild, moderate, and severe conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the expansion valve is completely closed when the indoor unit is turned off in cooling operation, then the system prevents flood-back and compressor damage, but the valve leakage problem causes incomplete closure leading to system faults
Solution Approach 1:
The patent implements a feedback mechanism by continuously monitoring the temperature difference between pipelines to detect valve leakage status. The system uses temperature sensors to measure pipeline temperatures and compares them against expected values to determine whether the valve is properly closed, providing continuous feedback on valve performance without requiring additional actuators or complex mechanisms.
Solution Approach 2:
The patent replaces direct mechanical measurement of valve position with thermal field measurement. Instead of using position sensors or mechanical indicators to detect valve closure status, the system uses temperature difference measurement of pipelines to indirectly infer valve leakage, substituting a simple thermal measurement approach for complex mechanical detection.
2Productivity
If the expansion valve maintains a small opening degree during heating operation, then the system ensures proper refrigerant flow, but valve leakage causes excessive opening leading to poor heating effect and abnormal pressure parameters
Solution Approach 1:
The system continuously monitors pipeline temperature differences to provide feedback on actual valve opening status during heating operation. By comparing measured temperature differences against expected values for proper valve opening, the system can detect when leakage causes excessive opening and adjust or alert operators accordingly.
Solution Approach 2:
The patent uses thermal field measurement to indirectly monitor valve opening degree during heating operation. Instead of using position sensors to directly measure valve opening, the system measures pipeline temperatures and calculates temperature differences to infer whether the valve maintains the proper small opening degree required for efficient heating.
3Measurement precision
If traditional detection methods are used to identify expansion valve leakage, then the system structure remains simple, but the leakage condition cannot be detected timely and accurately
Solution Approach 1:
The patent replaces complex mechanical or electronic valve position detection systems with a simple thermal measurement approach. By using temperature sensors to measure pipeline temperatures and calculating temperature differences, the system achieves accurate leakage detection without requiring additional position sensors, actuators, or complex detection electronics.
Solution Approach 2:
The patent introduces temperature difference as an intermediary parameter to detect valve leakage status. Instead of directly measuring valve position or refrigerant flow, the system uses pipeline temperature as an intermediate indicator that reflects valve performance, enabling indirect but accurate detection of leakage conditions.
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 method enables timely and accurate detection of expansion valve leakage, preventing compressor damage and ensuring effective operation by adjusting valve openings based on leakage severity, thereby enhancing system reliability and user experience.
Implementation Method 1
a temperature of the first pipeline and a temperature of the second pipeline are obtained when the indoor unit is in a turned-off state
Data Source
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AI summary
The present invention belongs to the technical field of heat exchange, and specifically relates to an expansion valve control method for a multi-split air-conditioning system. The present invention aims to solve the problem that it is not possible for an existing detection manner to detect the leakage of an expansion valve of a multi-split air-conditioning system in an accurate and timely manner. To this end, the multi-split air-conditioning system of the present invention comprises an outdoor unit and a plurality of indoor units connected to the outdoor unit, wherein each of the indoor units is connected to the outdoor unit by means of a first pipeline and a second pipeline. The expansion valve control method of the present invention comprises: 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 the indoor temperature of the environment where 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, determining the leakage condition of an expansion valve of the indoor unit, such that the multi-split air-conditioning system can detect the leakage condition of the expansion valve in a timely and accurate manner.