Refrigeration cycle device
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Solution Overview
Problem
Existing air conditioning devices face challenges in accurately determining refrigerant quantity due to increased subcooling degree, leading to inefficient operation and difficulty in detecting refrigerant leakage, especially when external disturbances like outdoor temperature variations occur.
Innovation Solution
The proposed configuration includes a controller that calculates the subcooling degree at the outlet of the subcooling device and determines the refrigerant quantity by comparing it with a threshold, using sensors to adjust the liquid injection valve and compressor rotation speed, allowing for precise refrigerant circulation quantity estimation and leakage detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the subcooling degree is increased to keep detection accuracy, then the detection accuracy of refrigerant quantity is improved, but the discharging pressure at the compressor increases, making high efficient operation impossible
Solution Approach 1:
The patent applies dynamics by making the subcooling degree adjustable rather than fixed. The control unit dynamically adjusts the subcooling degree based on operational requirements: increasing it during refrigerant quantity detection to improve measurement accuracy, and decreasing it during normal operation to maintain compressor efficiency. This dynamic adjustment resolves the contradiction between detection accuracy and operational efficiency.
Solution Approach 2:
The patent changes the parameter of subcooling degree from a constant value to a variable parameter that can be adjusted based on system needs. By modifying this thermodynamic parameter, the system achieves high-accuracy refrigerant quantity detection when needed while maintaining efficient compressor operation during normal conditions, thus resolving the contradiction between measurement precision and energy efficiency.
2Ease of operation
If the subcooling degree is kept constant, then the operation is simplified, but it is impossible to perform refrigerant quantity determination with the condenser subcooling degree
Solution Approach 1:
The system dynamically adjusts the subcooling degree based on operational mode. During refrigerant quantity determination, the control unit increases the subcooling degree to enable accurate detection. During normal operation, it maintains a standard subcooling degree for simplicity. This dynamic behavior allows the system to achieve both operational simplicity and accurate refrigerant quantity determination at different times.
3Quantity of substance
If the liquid injection valve is controlled to increase subcooling degree, then the refrigerant circulation quantity increases, but the determination accuracy is insufficient for responding to operation state with wider range variation
Solution Approach 1:
The patent implements feedback control where the control unit continuously monitors the operation state (such as outdoor temperature, heat exchanger conditions) and adjusts the subcooling degree and liquid injection valve control accordingly. This feedback mechanism enables the system to adapt to a wide range of operation states, maintaining determination accuracy across varying conditions by responding to real-time system state information.
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 high-accuracy determination of refrigerant quantity and leakage detection, maintaining efficient operation even under varying conditions, thus preventing refrigerant-related issues like global warming and ensuring safe operation.
Implementation Method 1
a subcooling device 16 that subcools the refrigerant condensed by the outdoor heat exchanger 11
Implementation Method 2
a liquid injection valve 17 that injects the refrigerant subcooled by the subcooling device 16 into a suction line of the compressor 14
Implementation Method 3
a compressor 14 that compresses a refrigerant
Implementation Method 4
an outdoor heat exchanger 11 that condenses the refrigerant compressed by the compressor 14
Implementation Method 5
an indoor heat exchanger 21 that evaporates the refrigerant condensed by the outdoor heat exchanger 11
Data Source
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AI summary
A refrigeration cycle device, provided with: a compressor (14); a condenser (11); an evaporator (21); a pressure reducer (23); a subcooler (16) performing subcooling on a refrigerant passing through the condenser (11); a subcooling degree calculation unit (114) estimating a suitable subcooling degree of the refrigerant of an outlet of the subcooler (16) on the basis of a refrigerant cycle amount of a portion from the compressor (14) via the condenser (11) and the subcooler (16), and calculating, on the basis of the estimated suitable subcooling degree, a determination threshold value used for determining a refrigeration measurement; a refrigerant determination unit (115) comparing a measured subcooling degree and the determination threshold value, and thereby determining a refrigerant amount.