Method for controlling multi-split air conditioner, multi-split air conditioner system, and computer-readable storage medium

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Solution Overview

Problem

Multi-split air conditioner systems experience uneven refrigerant distribution among outdoor units due to installation location, spacing, and drop height, leading to abnormal operation, high exhaust temperatures, and potential damage to compressors.

Innovation Solution

A method for controlling a multi-split air conditioner system by detecting the degree of superheat and average exhaust temperature of each outdoor unit, adjusting the electronic expansion valve to balance the refrigerant distribution, and ensuring the average exhaust temperature of each unit approximates the system average, thereby maintaining even refrigerant distribution and controlling exhaust temperatures effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If outdoor units are connected in parallel with the same pipe diameter and valve body control, then the device complexity is reduced and installation is simplified, but uneven refrigerant distribution occurs leading to abnormal operation and potential damage

Engineering Contradiction:
Improvepipe diameter and valve body control configurationVSAvoidrefrigerant distribution uniformity
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies local quality by making each outdoor unit have different electronic expansion valve opening degrees based on its specific location and refrigerant distribution needs. Instead of using the same valve control for all units, each unit's expansion valve is independently adjusted to compensate for variations in installation location, spacing, and drop height, thereby achieving uniform refrigerant distribution while maintaining simple parallel connection configuration.

Inventive Principle:
Principle #3Local quality

2Reliability

If electronic expansion valve opening degree is increased to compensate for low refrigerant, then refrigerant distribution is improved, but exhaust temperature may become excessively high causing compressor damage

Engineering Contradiction:
Improverefrigerant distribution uniformityVSAvoidexhaust temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent implements feedback control by continuously monitoring the exhaust temperature of each outdoor unit and using this information to adjust the electronic expansion valve opening degree. The control system compares the actual exhaust temperature with the average exhaust temperature of all outdoor units, and dynamically adjusts each unit's expansion valve to maintain temperature balance, preventing both insufficient refrigerant and excessive exhaust temperature that could damage compressors.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes the operating parameters of the electronic expansion valve by adjusting its opening degree based on exhaust temperature measurements. Instead of using a fixed valve opening, the system dynamically modifies the valve parameter (opening degree) for each outdoor unit according to its specific exhaust temperature, thereby achieving balanced refrigerant distribution and controlled exhaust temperatures across all units.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the control system monitors and adjusts each outdoor unit individually, then refrigerant distribution is balanced, but the control system complexity increases

Engineering Contradiction:
Improverefrigerant distribution uniformityVSAvoidcontrol system structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies universality by using a single control system that performs multiple functions: it monitors exhaust temperature, calculates average temperature, determines opening degree adjustments, and controls electronic expansion valves for all outdoor units. This multi-functional approach achieves individualized control for each unit while avoiding the need for separate control systems, thereby balancing refrigerant distribution without proportionally increasing control system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 ensures even refrigerant distribution and effectively controls exhaust temperatures across all outdoor units, preventing compressor damage and improving the reliability of the multi-split air conditioner system.

Implementation Method 1

detecting whether a degree of superheat of each outdoor unit meets a target requirement

Methodology Applied
Scientific EffectSuperheat: Superheating

Implementation Method 2

the average exhaust temperature of each outdoor unit is the average of the exhaust temperatures of all compressors in each outdoor unit

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Data Source

PatentEP3598013B1Method for controlling multi-split air conditioner, multi-split air conditioner system, and computer-readable storage medium
Publication Date: 2022.10.19 GD MIDEA HEATING & VENTILATING EQUIP CO LTD
  • EP3598013B1 patent drawingFigure 1
  • EP3598013B1 patent drawingFigure 1A
  • EP3598013B1 patent drawingFigure 2

AI summary

A method for controlling a multi-split air conditioner. The method comprising the steps of: step S10, detecting whether the degree of superheat of each outdoor unit meets a target requirement; step S20, if yes, determining whether a difference between an average exhaust temperature of each outdoor unit and an average exhaust temperature of an outdoor unit system reaches a preset value; step S30, if yes, comparing the size of the average exhaust temperature of each outdoor unit with the size of the average exhaust temperature of the outdoor unit system; and step S40, according to the result between the size of the average exhaust temperature of each outdoor unit and the size of the average exhaust temperature of the outdoor unit system, controlling an electronic expansion valve to actuate to make the average exhaust temperature of each outdoor unit to approximate to the average exhaust temperature of the outdoor unit system. By controlling the degree of opening of an electronic expansion valve, the problem of refrigerant maldistribution in a multi-split air conditioner system is resolved, and the exhaust temperature of the system is effectively controlled. Also disclosed are a multi-split air conditioner system and a computer-readable storage medium.