Refrigeration cycle apparatus and control method thereof
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Solution Overview
Problem
The refrigeration cycle apparatus faces operational challenges due to variations in the mixture ratio of difluoromethane, which can disrupt the normal operation state despite unchanged control settings, especially when regular and recovered refrigerants are mixed.
Innovation Solution
Incorporating a judgement unit to determine the mixture ratio of difluoromethane within the refrigerant circuit and a control unit to adjust the refrigeration cycle operations based on this ratio, using methods such as discharge temperature or weights of refrigerants, to maintain a normal operational state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If recovered refrigerant and regular refrigerant are mixed and charged to the refrigerant circuit, then the refrigerant can be reused and cost reduced, but the mixture ratio of difluoromethane may differ from the regular refrigerant and change the state of the refrigeration cycle, making it impossible to keep a normal operation state
Solution Approach 1:
The control unit changes operating parameters (compressor discharge pressure, expansion valve opening degree) based on the difluoromethane mixture ratio to maintain normal refrigeration cycle operation. When the mixture ratio differs from the standard, the controller adjusts these parameters to compensate for the changed refrigerant properties and keep the system operating normally.
2Adaptability or versatility
If the mixture ratio of difluoromethane changes in the charged refrigerant, then the refrigerant composition adapts to mixed refrigerants, but the state of the refrigeration cycle changes and normal operation cannot be maintained without control adjustment
Solution Approach 1:
The system incorporates a judgement unit that detects the difluoromethane mixture ratio and provides feedback to the control unit. Based on this feedback, the control unit automatically adjusts control parameters to maintain stable refrigeration cycle operation, creating a closed-loop control system that adapts to varying refrigerant compositions.
3Measurement precision
If a judgement unit is added to detect the mixture ratio of difluoromethane, then the control unit can perform precise control based on the actual refrigerant composition, but the device complexity increases
Solution Approach 1:
The judgement unit replaces complex physical analysis methods with simpler detection means to determine the difluoromethane mixture ratio. This substitution allows for easier and more accurate measurement of refrigerant composition without requiring complex analytical equipment, thereby reducing overall system complexity while maintaining measurement precision.
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 solution allows for precise control of the refrigeration cycle, ensuring the apparatus remains in a normal operational state by adjusting compressor revolutions, injection frequencies, and expansion valve openings based on the difluoromethane mixture ratio, thereby maintaining efficiency and preventing excessive dryness or temperature increases.
Implementation Method 1
the judgement unit judges the mixture ratio of the difluoromethane based on a discharge temperature of the refrigerant of the compressor in operation under a prescribed condition
Implementation Method 2
a refrigerant circuit that includes a compressor and performs a refrigeration cycle by circulating a refrigerant with the compressor
Implementation Method 3
performs a refrigeration cycle by circulating a refrigerant with the compressor
Data Source
AI summary
A refrigeration cycle apparatus is caused to be in a normally operable state in accordance with the mixture ratio of difluoromethane occupying a refrigerant charged in the refrigeration cycle apparatus. A refrigeration cycle apparatus includes a refrigerant circuit including a compressor and performs a refrigeration cycle by circulating a refrigerant in the refrigerant circuit with the compressor. A heat-source-side controller judges the mixture ratio of difluoromethane occupying the refrigerant charged in the refrigerant circuit. The heat-source-side controller further performs control relating to the refrigeration cycle on the basis of the mixture ratio of difluoromethane judged by the judgement unit. The controller judges the mixture ratio of difluoromethane on the basis of a discharge temperature of the refrigerant of the compressor in operation under a prescribed condition or judges the mixture ratio of difluoromethane on the basis of weights of a plurality of types of refrigerants to be charged to the refrigerant circuit.