Refrigeration cycle apparatus
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Solution Overview
Problem
Refrigeration cycle apparatuses using carbon dioxide as a refrigerant face the challenge of refrigerant solidification due to pressure drops during filling, which can damage components and hinder efficient operation.
Innovation Solution
A control system that adjusts the compressor's rotation speed based on pressure detection to maintain refrigerant pressure above the triple point of carbon dioxide, preventing solidification and ensuring smooth filling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If refrigerant filling is performed rapidly, then filling efficiency is improved, but refrigerant pressure decreases causing solidification
Solution Approach 1:
The compressor is activated before refrigerant filling begins to pre-establish positive pressure in the refrigerant circuit. This preliminary action prevents pressure drop during subsequent rapid filling, allowing high filling efficiency without causing refrigerant solidification.
Solution Approach 2:
The control unit continuously monitors refrigerant pressure during filling and dynamically adjusts compressor operation based on pressure feedback. This ensures pressure remains above the triple point throughout the filling process, maintaining reliability while enabling rapid filling.
2Productivity
If compressor speed is increased, then refrigerant circulation is improved, but power consumption increases
Solution Approach 1:
The compressor speed is dynamically adjusted during the filling process rather than operating at constant high speed. The control unit varies compressor RPM based on real-time pressure conditions, providing high circulation only when needed to maintain pressure, thereby reducing overall power consumption.
Solution Approach 2:
The system changes the operational parameters of the compressor (rotation speed) based on the filling stage and pressure conditions. By adjusting speed rather than maintaining maximum speed continuously, the system achieves adequate refrigerant circulation with lower energy consumption.
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
Prevents refrigerant solidification, ensuring reliable operation and component protection by controlling compressor speed to manage pressure within safe limits during refrigerant filling.
Implementation Method 1
The detector detects a pressure of the refrigerant in a low pressure flow path of the refrigerant circuit
Implementation Method 2
the processor is configured to control the number of rotations of the compressor on the basis of a detection value of the detector
Implementation Method 3
from a refrigerant storage container to the refrigerant circuit... prevent the refrigerant flowing into a refrigerant circuit due to a rapid pressure decrease at the time of filling a refrigeration cycle apparatus from entering a solid state (dry ice state)
Data Source
AI summary
The refrigeration cycle apparatus includes a refrigerant circuit, a heat source, a utilizer, a detector, and a processor. The refrigerant circuit includes a compressor, and a carbon dioxide refrigerant flows through the refrigerant circuit. The heat source accommodates the compressor. The utilizer is connected to the heat source via a connecting pipe. The detector detects a pressure of the refrigerant in a low pressure flow path of the refrigerant circuit. The processor is configured to execute a refrigerant filling operation of moving the refrigerant from a refrigerant storage container to the refrigerant circuit. In the refrigerant filling operation, the processor is configured to control the number of rotations of the compressor on the basis of a detection value of the detector.