Multi-Split Air Conditioning Superheat Control for Dewing Prevention

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Solution Overview

Problem

Existing control methods for single-split air conditioning systems are not applicable to multi-split systems, leading to issues such as low outlet air temperature and dewing in different operational modes, due to differences in refrigerant pipeline structure and complex control logics.

Innovation Solution

A method for controlling multi-split air conditioning systems by determining degrees of superheat based on operation statuses, using temperature characteristics and evaporation outlet temperatures to adjust throttling elements, considering the air blowing mode and compressor stability, to ensure precise control and user comfort.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If single-split control methods are applied to multi-split systems, then control simplicity is maintained, but control precision and system reliability deteriorate due to differences in refrigerant pipeline structure and complex operational modes

Engineering Contradiction:

Improvecontrol logic complexityVSAvoidsystem operation reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The control method segments the multi-split system into independent indoor unit control loops, where each indoor unit's electronic expansion valve is controlled independently based on its own operational mode and temperature requirements. This segmentation allows each unit to be optimized separately while maintaining overall system reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements local quality control by adjusting the degree of superheat for each indoor unit according to its specific operational mode (e.g., breezeless mode, gentle breeze mode, anti-direct blowing mode). Each indoor unit receives customized control parameters based on its local requirements, improving both reliability and control precision.

Inventive Principle:

Principle #3Local quality

2Productivity

If compressor is controlled according to regular cooling mode logic, then cooling capacity is maximized, but outlet air temperature decreases and dewing occurs in air blowing modes

Engineering Contradiction:

Improvecooling capacityVSAvoiddewing and low outlet air temperature

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The control system dynamically adjusts the degree of superheat based on the indoor unit's operational mode. When air blowing modes are detected, the system dynamically modifies control parameters to increase outlet air temperature and prevent dewing, while maintaining cooling capacity through real-time feedback from temperature sensors.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes key control parameters (degree of superheat, electronic expansion valve opening degree) based on operational mode. By adjusting these parameters dynamically, the system prevents dewing and maintains appropriate outlet air temperature while preserving cooling effectiveness.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If evaporation outlet temperature is used as control parameter, then control accuracy improves, but system complexity increases due to additional measurement requirements

Engineering Contradiction:

Improvetemperature measurement precisionVSAvoidcontrol system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The outdoor unit's temperature sensor serves multiple functions: it measures evaporation outlet temperature for control purposes and also provides data for monitoring overall system performance. This multi-functionality reduces the need for additional dedicated sensors, minimizing system complexity while maintaining measurement precision.

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 enables precise control of indoor units in multi-split systems, improving user experience by ensuring stable operation and personalized air blowing requirements while avoiding dewing and temperature deviations.

Implementation Method 1

a temperature characteristic value of an evaporator coil of the target indoor unit

Methodology Applied

Scientific EffectHeat absorption: Absorption (physical)

Implementation Method 2

adjusting an opening degree of a throttling element of the target indoor unit

Methodology Applied

Scientific EffectThrottling: Pressure Drop

Data Source

PatentUS20260029149A1Multi-split air conditioning system control method, controller, air conditioning system, and medium

Publication Date: 2026.01.29 GD MIDEA AIR CONDITIONING EQUIP CO LTD

AI summary

In a control method, a first degree of superheat of a target indoor unit is determined according to a temperature characteristic value of an evaporator coil and an evaporation outlet temperature value of the target indoor unit, and an air blowing correction coefficient when a preset condition is met or a second degree of superheat of the target indoor unit is determined according to the temperature characteristic value and the evaporation outlet temperature value when the preset condition is not met. An opening degree of a throttling element of the target indoor unit is adjusted according to the first or second degree of superheat. The air blowing correction coefficient is related to an air blowing mode of the target indoor unit. The evaporation outlet temperature value is measured at a point on an outdoor unit side.