Refrigeration cycle apparatus
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Solution Overview
Problem
Conventional refrigeration cycle apparatuses, such as air conditioners, experience degradation in user comfort due to heat discharge during the transition from heating to cooling operations, as they do not effectively prevent liquid refrigerant backflow into the compressor, leading to reduced performance and potential compressor failure.
Innovation Solution
A refrigeration cycle apparatus with a controller that selectively switches the refrigerant circulation direction between two paths, using decompressors and a flow path switch to manage the refrigerant flow, ensuring that the compressor operates without liquid backflow by prioritizing the decompression of specific heat exchangers based on elapsed time and user comfort requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the heating cycle is carried out when cooling operation is started to prevent liquid back, then the compressor is protected from liquid refrigerant, but heat is discharged from the indoor unit causing degradation of user comfort
Solution Approach 1:
The patent segments the refrigerant circulation path by introducing a bypass line that connects the compressor discharge side to the indoor heat exchanger. This allows the refrigeration cycle to be divided into two parallel paths: the main cooling path through the four-way valve, and the bypass path for liquid refrigerant removal. This segmentation enables simultaneous cooling operation and liquid back prevention without discharging heat into the indoor space.
Solution Approach 2:
The patent introduces an expansion valve as an intermediary component in the bypass line. This expansion valve acts as a mediator that controls the flow of liquid refrigerant from the indoor heat exchanger back to the compressor suction side, enabling precise control of the liquid removal process without affecting the main cooling cycle and thus maintaining user comfort.
2Reliability
If liquid refrigerant is transported from indoor unit to outdoor unit through heating cycle, then liquid back is avoided, but the system complexity increases due to cycle switching
Solution Approach 1:
The patent merges the liquid back prevention function with the existing cooling cycle operation. Instead of requiring a separate heating cycle or complex cycle switching, the bypass line is integrated into the cooling cycle configuration. The four-way valve maintains the cooling mode while the bypass line handles liquid refrigerant removal, combining both functions in a single operational mode and reducing system complexity.
3Productivity
If the compressor is activated immediately after refrigerant circulation starts, then productivity is improved, but liquid refrigerant may be sucked into the compressor causing liquid back
Solution Approach 1:
The patent implements preliminary action by establishing the bypass line connection before the compressor starts operating. The bypass line is pre-configured and the expansion valve is positioned to enable immediate liquid refrigerant removal from the indoor heat exchanger. This preliminary setup ensures that as soon as the compressor activates, liquid refrigerant can be continuously removed through the bypass path, preventing liquid back while allowing immediate compressor operation and maintaining high productivity.
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 effectively suppresses user discomfort by minimizing heat discharge during cooling operations and enhances the stability of the refrigeration cycle apparatus by preventing liquid backflow, thus maintaining optimal compressor performance.
Implementation Method 1
a first decompressor; a second decompressor... control the first decompressor and the second decompressor such that an opening degree of the specific decompressor is larger than an opening degree of a decompressor
Implementation Method 2
a first heat exchanger; a second heat exchanger; a third heat exchanger... the refrigerant is circulated in order of the first heat exchanger, the compressor, the second heat exchanger
Implementation Method 3
the refrigerant is circulated... heat is discharged from the indoor unit... Air warmed by this heat is thus blown from the indoor unit
Implementation Method 4
a compressor... control the compressor... the refrigerant is circulated in order of the first heat exchanger, the compressor, the second heat exchanger
Data Source
AI summary
The refrigerant circulation direction is switched between first and second circulation directions. In the first circulation direction, the refrigerant is circulated in order of a first heat exchanger, a compressor, a second heat exchanger, and a first decompressor, and circulated in order of the first heat exchanger, the compressor, a third heat exchanger, and a second decompressor. A controller identifies a specific heat exchanger from among the second heat exchanger and the third heat exchanger. When an elapsed time from activation of the compressor is shorter than a reference time, the controller makes an opening degree of a specific decompressor that communicates with the specific heat exchanger larger than an opening degree of the decompressor that is among the first decompressor and the second decompressor and different from the specific decompressor, and sets the refrigerant circulation direction to the second circulation direction opposite to the first circulation.