Multi-split air conditioner and control method therefor, storage medium, and electronic device
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Solution Overview
Problem
Multi-split air conditioners face reliability issues and increased maintenance costs due to abnormal compressor starts and vibrations caused by refrigerant migration during ultra-low-temperature heating, especially after long periods of standby, leading to compressor damage.
Innovation Solution
A control method for multi-split air conditioners that evaluates starting severity based on system parameters before low-temperature heating, using pressure deviation calculations to determine appropriate starting strategies, including preheating and frequency adjustments to prevent refrigerant migration and ensure safe startup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the multi-split air conditioner is started directly after long period ultra-low temperature standby, then the system can quickly begin heating operation, but liquid refrigerant migrates to the outdoor unit and compressor due to gravity and temperature difference, causing abnormal compressor starting and system vibration
Solution Approach 1:
The patent applies preliminary action by performing preheating of the outdoor unit heat exchanger and low pressure tank before compressor startup. The control method calculates a preheating time based on the height difference between indoor and outdoor units, and activates heating elements to warm the refrigerant in these components before the compressor starts, preventing liquid refrigerant migration and ensuring reliable compressor operation
2Reliability
If the outdoor unit is positioned below the indoor unit, then refrigerant gravity migration is reduced, but the patent specifically addresses systems with multiple refrigerant conditions and height differences where the indoor unit is above the outdoor unit
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the preheating time parameter based on the height difference between indoor and outdoor units. The control method calculates the preheating time using the formula: preheating time = k × h, where h is the height difference and k is a coefficient. This adaptive parameter adjustment optimizes the preheating duration for different installation configurations, ensuring reliable operation while accommodating various system setups
3Quantity of substance
If the low pressure tank is filled with full liquid refrigerant, then the refrigerant storage capacity is maximized, but the low pressure tank directly returns liquid refrigerant to the compressor air return port, causing liquid in the suction air and compressor damage
Solution Approach 1:
The patent applies preliminary action by preheating the low pressure tank before compressor startup to vaporize liquid refrigerant and prevent liquid return to the compressor. The control method activates heating elements in the low pressure tank during the preheating phase, ensuring that when the compressor starts, the refrigerant in the low pressure tank is in a vapor or gas-liquid mixture state rather than full liquid, thereby protecting the compressor from liquid damage
Solution Approach 2:
The patent uses the heating elements in the low pressure tank as an intermediary to transform the state of refrigerant from liquid to vapor/gas-liquid mixture. This intermediary heating mechanism prevents direct liquid refrigerant return to the compressor by mediating the phase change, thereby protecting the compressor while maintaining adequate refrigerant storage capacity
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
The method improves the reliability of multi-split air conditioners and reduces maintenance costs by preventing compressor damage and abnormal vibrations during low-temperature heating, ensuring safe and efficient system operation.
Implementation Method 1
a compressor compresses the refrigerant gas
Implementation Method 2
the outdoor heat exchanger condenses the refrigerant
Implementation Method 3
a large amount of low temperature liquid refrigerant migrates to the outdoor unit side of the multi-split system due to gravity and temperature difference
Implementation Method 4
obtaining a pressure deviation according to the high pressure of the outdoor unit and the theoretical discharge pressure; and performing starting control of the multi-split system according to the pressure deviation
Data Source
AI summary
A control method includes obtaining a theoretical discharge pressure according to a geometric parameter of an outdoor unit of a multi-split air conditioner, an air supply port parameter of an indoor unit of the multi-split air conditioner, an outdoor ambient temperature, and an indoor ambient temperature, obtaining a pressure deviation according to a high pressure of the outdoor unit and the theoretical discharge pressure, and performing starting control of the multi-split air conditioner according to the pressure deviation.