Multi-split air conditioner, and method and device for controlling multi-split air conditioner
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Solution Overview
Problem
Multi-split air conditioners experience insufficient subcooling degree before the electronic expansion valve, leading to abnormal throttling noise, especially in installations with long pipes and large falling heads, despite increased subcooling at the outdoor unit, due to pipeline pressure loss and heat loss.
Innovation Solution
Incorporating a subcooling parallel section and a subcooling branch connected in parallel with the main pipeline, with a switching connection assembly that adjusts the refrigerant flow to ensure adequate subcooling before the electronic expansion valve, using solenoid valves and a damper to control airflow and subcooling degree.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the refrigerant flows through long pipes with large falling heads, then the refrigerant reaches the indoor units, but pipeline pressure loss and heat loss cause insufficient subcooling degree before the electronic expansion valve
Solution Approach 1:
The patent implements preliminary subcooling actions at two stages: first at the outdoor unit before refrigerant enters the pipeline, and second at each indoor unit before the refrigerant reaches the electronic expansion valve. This preliminary action ensures that even after long pipeline transport with pressure and heat losses, the refrigerant maintains sufficient subcooling degree for proper throttling operation.
Solution Approach 2:
The patent introduces intermediate subcooling sections at each indoor unit as mediator elements between the outdoor unit and the electronic expansion valve. These intermediate subcooling sections compensate for the deteriorating effects of long pipeline transport, acting as a buffer to maintain the required subcooling degree despite pipeline losses.
2Temperature
If the subcooling degree before the electronic expansion valve is insufficient, then the refrigerant is in a gas-liquid two-phase state, but this causes extreme throttling noise
Solution Approach 1:
The patent applies preliminary anti-action by implementing subcooling sections that prevent the refrigerant from entering the gas-liquid two-phase state before the electronic expansion valve. By ensuring the refrigerant remains in a liquid state with sufficient subcooling degree through dual-stage subcooling, the system preemptively eliminates the condition that would cause extreme throttling noise.
Solution Approach 2:
The patent converts the potential harm of long pipeline losses into a benefit by designing a distributed subcooling system where each indoor unit has its own subcooling capability. This transforms the problem of pipeline-induced subcooling loss into an opportunity for localized subcooling control, ensuring proper refrigerant state and eliminating throttling noise.
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 stabilizes the refrigerant throttling process, reducing abnormal throttling noise by ensuring a sufficient subcooling degree before the electronic expansion valve, improving the overall performance of the multi-split air conditioner.
Implementation Method 1
a subcooling branch comprising a subcooler
Implementation Method 2
The subcooler is disposed at a wind area of an air outlet side of the indoor heat exchanger
Data Source
AI summary
A multi-split air conditioner comprising an outdoor unit and a group of indoor units, the group of indoor units comprising a plurality of indoor units connected in parallel, at least one indoor unit comprising: a main flow path, comprising an electronic expansion valve and an indoor heat exchanger successively connected via a main pipeline, at least part of the main pipeline located at a refrigerant inlet end of the electronic expansion valve being used as a supercooling parallel section; a supercooling branch, comprising a supercooler, the supercooling branch being connected in parallel to the supercooling parallel section; and a communication switching assembly, configured to be controlled to communicate the supercooling parallel section and/or the supercooling branch with the electronic expansion valve.