Refrigeration cycle device
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Solution Overview
Problem
In refrigeration cycle apparatuses, liquid backflow to the compressor occurs during defrosting operations due to surplus refrigerant stored in a high-pressure receiver, which is not effectively suppressed by existing solutions, leading to increased apparatus size and cost.
Innovation Solution
A refrigeration cycle apparatus with a liquid backflow suppression circuit connected in parallel to the first expansion device, including a second expansion device, an on-off valve, and a high-pressure receiver, controlled by a controller to manage refrigerant flow and prevent backflow during defrosting and other operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an accumulator is installed on the suction side of the compressor to store liquid refrigerant, then liquid backflow to the compressor is suppressed, but the apparatus size and cost increase due to the large installation space required
Solution Approach 1:
The patent extracts the liquid backflow suppression function from the traditional accumulator component and relocates it to the high-pressure receiver. By utilizing the existing high-pressure receiver's space and function, the invention eliminates the need for a separate accumulator, thereby suppressing liquid backflow while avoiding increased apparatus size
Solution Approach 2:
The high-pressure receiver is given multiple functions: it continues to store surplus refrigerant as before, and now also serves to suppress liquid backflow during defrosting operations. This multi-functional design eliminates the need for dedicated components for each function, reducing overall apparatus size while maintaining reliability
2Stress or pressure
If a bypass with solenoid valve is connected in parallel to the expansion valve to cause refrigerant to flow to the water heat exchanger side during defrosting, then low-pressure-side pressure reduction is suppressed, but liquid backflow to the compressor cannot be effectively prevented
Solution Approach 1:
The patent introduces the high-pressure receiver as an intermediary component between the expansion valve and the defrosting system. During defrosting operations, the high-pressure receiver mediates by storing liquid refrigerant and preventing it from flowing back to the compressor, while still allowing the bypass to function for maintaining low-pressure-side pressure
Solution Approach 2:
The patent segments the refrigerant flow control into two independent pathways: one through the expansion valve for normal operation, and another through the high-pressure receiver for liquid backflow suppression during defrosting. This segmentation allows each component to specialize in its function without compromising the other
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
Effectively suppresses liquid backflow to the compressor during defrosting and other operations, reducing the need for a large accumulator and minimizing apparatus size and cost.
Implementation Method 1
a high-pressure receiver configured to store surplus refrigerant
Implementation Method 2
a liquid backflow suppression circuit connected in parallel to the first expansion device, the liquid backflow suppression circuit including a second expansion device, an on-off valve, and a high-pressure receiver connected between the second expansion device and the on-off valve
Data Source
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AI summary
Provided is a refrigeration cycle apparatus, including: a refrigerant circuit including a compressor, a flow switching device, a heat source-side heat exchanger, a first expansion device, and a use-side heat exchanger; and a liquid backflow suppression circuit connected in parallel to the first expansion device, the liquid backflow suppression circuit including a second expansion device, an on-off valve, and a high-pressure receiver connected between the second expansion device and the on-off valve.