Outdoor unit of multi-split air conditioner and multi-split air conditioner having same
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Solution Overview
Problem
The existing two-tube type heat recovery VRF air conditioning systems face an unacceptable pressure drop when using gas-liquid two-phase refrigerants through flow-distribution capillary tubes, leading to a worse flow distributing effect and performance of the heat exchanger.
Innovation Solution
The proposed outdoor unit for a VRF air conditioning system includes a refrigerant flow path connected in parallel to the outdoor heat exchanger and electronic expansion valve, with an adjusting valve assembly and one-way valves, allowing gaseous and liquid refrigerants to converge, reducing pressure drop and improving flow distribution through capillary tubes while meeting cooling and heating requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If gas-liquid two-phase refrigerant flows through flow-distribution capillary tubes, then cooling and heating functions are provided, but unacceptable pressure drop is produced
Solution Approach 1:
The patent divides the refrigerant flow path into separate liquid-phase and gas-phase channels. The liquid refrigerant flows through the outdoor heat exchanger while gaseous refrigerant bypasses it, avoiding the pressure drop issue of two-phase flow through capillary tubes while still enabling both cooling and heating functions.
Solution Approach 2:
The patent introduces a refrigerant flow path as an intermediary component that allows gaseous refrigerant to bypass the outdoor heat exchanger. This intermediary path mediates between the need for cooling/heating functionality and the need to avoid excessive pressure drop, enabling selective routing of refrigerant phases.
2Stress or pressure
If flute-shaped tubes are used for flow distribution instead of capillary tubes, then pressure drop is reduced, but flow distributing effect becomes worse
Solution Approach 1:
Instead of using flute-shaped tubes that reduce pressure drop but worsen flow distribution, the patent segments the flow paths into separate liquid and gas channels. This segmentation allows the liquid refrigerant to be properly distributed through the outdoor heat exchanger while the gas refrigerant takes a separate path, achieving both good flow distribution and acceptable pressure drop.
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 configuration ensures an excellent flow distributing effect, reduces refrigerant pressure drop, and maintains adequate flow rate, enhancing the performance of the outdoor unit by allowing simultaneous cooling and heating capabilities.
Implementation Method 1
a first one-way valve is connected to each pipeline in series, the first one-way valve is opened only in one direction from the second valve port to the electronic expansion valve
Implementation Method 2
flow-distribution capillary tubes
Implementation Method 3
outdoor heat exchanger
Implementation Method 4
electronic expansion valve
Data Source
Figure 1
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Figure 3
AI summary
An outdoor unit (100) for a VRF air conditioning system and a VRF air conditioning system having the same are provided. The outdoor unit (100) comprises: a compressor (10); a reversing assembly (20); an outdoor heat exchanger (30) comprising an header (31), an heat exchange portion (32), a plurality of flow-distribution capillary tubes (33) and a flow distributor (34); an electronic expansion valve (40) connected to the flow distributor (34); an refrigerant flow path (50) and an adjusting valve assembly (60), in which the refrigerant flow path (50) is connected to the electronic expansion valve (40), and the adjusting valve assembly (60) is connected to the refrigerant flow path (50) in series; a reversing valve assembly (70) configured to make the refrigerant flow out of the outdoor unit (100) via the second stop valve (120), and make the refrigerant flow into the outdoor unit (100) via the first stop valve (110).