Air-conditioning apparatus
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Solution Overview
Problem
During the installation of air-conditioning apparatuses, foreign matter can enter the refrigerant circuit when extension pipes and refrigerant pipes are welded together, potentially clogging the expansion valve and leading to liquid backflow, which damages the compressor and reduces the efficiency of the air-conditioning system.
Innovation Solution
An air-conditioning apparatus with a controller that adjusts the opening degree of the expansion valve, includes a valve opening-degree adjusting module, a flow-rate determination module, and a clogging determination module. The controller produces a control signal to manage the expansion valve's opening degree and determines if the valve is clogged by comparing the refrigerant flow rate downstream of the expansion valve with a threshold, indicating if foreign matter is present.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If extension pipes and refrigerant pipes are welded together during installation, then the air-conditioning apparatus can be installed at designated places, but foreign matter may enter the refrigerant circuit and clog the expansion valve
Solution Approach 1:
The system performs preliminary monitoring of refrigerant flow rate before foreign matter causes complete clogging. By continuously comparing the refrigerant flow rate with a threshold value and detecting abnormal valve opening degree changes, the system identifies potential clogging early and takes preventive actions before the expansion valve fails completely.
Solution Approach 2:
The system implements feedback control by continuously monitoring the refrigerant flow rate downstream of the expansion valve and comparing it with threshold values. When the flow rate falls below the threshold or the valve opening degree changes abnormally, the system generates alerts and can automatically adjust the valve opening degree to maintain proper refrigerant flow.
2Reliability
If the expansion valve is clogged with foreign matter, then the valve cannot adjust refrigerant flow rate appropriately, but refrigerant continues to flow at abnormal rates causing liquid backflow
Solution Approach 1:
The system continuously monitors refrigerant flow rate downstream of the expansion valve and compares it with a predetermined threshold. When the flow rate falls below the threshold, indicating potential clogging, the system generates an alert and can automatically adjust the valve opening degree to maintain proper refrigerant flow and prevent liquid backflow to the compressor.
Solution Approach 2:
The system takes preliminary anti-action by detecting abnormal valve opening degree changes and low refrigerant flow rates before complete clogging occurs. By identifying these early signs of trouble, the system can generate alerts and adjust valve operation to prevent the development of conditions that would cause liquid backflow and compressor damage.
3Ease of operation
If the expansion valve opening degree is controlled to be constant or moved in closing direction, then the valve operates as intended, but foreign matter clogging cannot be detected without flow rate monitoring
Solution Approach 1:
The system implements feedback by continuously monitoring the refrigerant flow rate downstream of the expansion valve and comparing it with a predetermined threshold. When the flow rate falls below the threshold, the system determines that foreign matter clogging has occurred and generates an alert, enabling detection of clogging while the valve operates under simple control.
Solution Approach 2:
The system replaces complex mechanical inspection methods for detecting clogging with a flow rate sensing system. By using flow rate sensors and electronic comparison with threshold values, the system can detect foreign matter clogging through fluid dynamics measurements rather than requiring physical inspection or complex mechanical indicators.
Data Source
AI summary
The air-conditioning apparatus includes: a refrigerant circuit in which a compressor, an outdoor heat exchanger, the expansion valve, and an indoor heat exchanger are connected by pipes; and a controller. The controller includes a valve opening-degree adjusting module, a flow-rate determination module, and a clogging determination module.