Air conditioner
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Solution Overview
Problem
In air-conditioning apparatuses with multiple heat source units, determining the precise amount of refrigerant in the refrigerant circuit is challenging due to varying installation conditions and temperature disparities among heat source-side heat exchangers, leading to inaccurate subcooling measurements.
Innovation Solution
The apparatus includes a controller that adjusts the subcooling levels of each heat source unit to equalize the refrigerant flow, using determination units and adjustment mechanisms to ensure consistent subcooling across units, thereby allowing for accurate refrigerant charging based on either subcooling degree.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the amount of refrigerant is determined based on the degree of subcooling in a single heat source-side heat exchanger, then the refrigerant charging process is simple, but the determination accuracy deteriorates due to refrigerant drift caused by varying installation conditions and temperature disparities among multiple heat source units
Solution Approach 1:
The patent divides the refrigerant charging determination process into multiple independent measurements - one for each heat source-side heat exchanger. Instead of relying on a single subcooling measurement, the system measures subcooling degrees across all heat source-side heat exchangers separately, then selects the most appropriate value for determining the total refrigerant amount. This segmentation approach eliminates the impact of refrigerant drift in individual units while maintaining operational simplicity.
2Measurement precision
If the subcooling levels of multiple heat source units are equalized through active control, then the refrigerant amount determination accuracy is improved, but the system complexity increases due to additional control mechanisms
Solution Approach 1:
The patent implements dynamic control of subcooling levels in heat source-side heat exchangers by adjusting refrigerant flow rates in real-time. The system continuously monitors subcooling degrees and actively adjusts flow control valves to equalize subcooling levels across all heat source units during the refrigerant charging process. This dynamic adjustment ensures consistent measurement conditions without requiring permanent structural modifications to the system.
Solution Approach 2:
The system changes the operating parameters of heat source-side heat exchangers by adjusting refrigerant flow rates to achieve equalized subcooling levels. By modifying the flow rate parameter dynamically during the charging process, the system creates uniform thermal conditions across all units, thereby improving the accuracy of refrigerant amount determination without adding complex hardware.
3Measurement precision
If refrigerant flow rates are adjusted to equalize subcooling degrees among heat source units, then the accuracy of refrigerant charging determination is improved, but the control complexity increases
Solution Approach 1:
The patent implements a feedback control mechanism where the system continuously monitors the subcooling degrees of all heat source-side heat exchangers and adjusts refrigerant flow rates based on the measured deviations from the target equalized state. The control algorithm uses this feedback information to iteratively adjust flow control valves until subcooling levels are equalized across all units, ensuring accurate refrigerant charging determination while automating the control process.
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 enhances the precision of refrigerant charging by minimizing refrigerant drift and ensuring consistent subcooling levels, facilitating accurate determination of the refrigerant amount in the circuit.
Implementation Method 1
a first heat source-side heat exchanger (4a) and second heat source-side heat exchanger (4b), each functioning at least as a condenser
Implementation Method 2
first heat source-side degree of subcooling adjustment means (3a, 8a, 9a) which adjusts a first degree of subcooling in an outlet side of the first heat source-side heat exchanger (4a)
Data Source
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AI summary
In an air-conditioning apparatus comprising a plurality of heat source units, the amount of refrigerant charged into a refrigerant circuit is precisely determined when refrigerant is charged into the refrigerant circuit. An air-conditioning apparatus (100) comprises a first outdoor unit (1a) having a first outdoor heat exchanger (4a) and a first outdoor expansion valve (3a) for adjusting a first degree of subcooling in an outlet side of the first outdoor heat exchanger (4a), a second outdoor unit (1b) having a second outdoor heat exchanger (4b) and a second outdoor expansion valve (3b) for adjusting a second degree of subcooling in an outlet side of the second outdoor heat exchanger (4b), a first outdoor-side determination unit (62a) for determining the first degree of subcooling, a second outdoor-side determination unit (62b) for determining the second degree of subcooling, a first outdoor-side opening degree adjustment component (64a), and a second outdoor-side opening degree adjustment component (64b). The first outdoor-side opening degree adjustment component (64a) and the second outdoor-side opening degree adjustment component (64b) control the first outdoor expansion valve (3a) and the second outdoor expansion valve (3b) respectively so as to reduce the difference between the first degree of subcooling and the second degree of subcooling when refrigerant is charged into a refrigerant circuit having the first outdoor heat exchanger (4a) and the second outdoor heat exchanger (4b).