Multi-Indoor AC Control for Heat Exchange Balance

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Solution Overview

Problem

In air conditioning systems with multiple indoor units in the same space, operating efficiency can be suboptimal due to individual unit controls, leading to both thermo-ON and thermo-OFF units, which can result in inefficiencies despite high individual unit efficiencies.

Innovation Solution

An air conditioning system with a control device that relaxes the thermo-ON condition of thermo-OFF units when a predetermined condition is met, ensuring at least one unit has been continuously thermo-ON for a first elapsed time and thermo-OFF for a second elapsed time, allowing more units to switch thermo-ON, thereby increasing heat exchange area and reducing pressure differential.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the number of thermo-ON indoor units is increased, then heat exchange balance is improved and pressure differential is reduced, but system complexity increases

Engineering Contradiction:
Improveheat exchange balanceVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs feedback control where the outdoor unit continuously monitors the operation status and performance of indoor units. Based on this feedback, the outdoor unit adjusts the number of thermo-ON units and their setpoint temperatures to maintain optimal heat exchange balance and minimize pressure differential, achieving reliable operation without excessive complexity.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes operational parameters such as setpoint temperatures and operation status of indoor units to optimize system performance. By adjusting these parameters dynamically, the system achieves better heat exchange balance and reduced pressure differential without requiring complex structural modifications.

Inventive Principle:
Principle #35Parameter changes

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 approach enhances overall system efficiency by increasing the number of thermo-ON units, balancing heat exchange, and reducing pressure differential, while preventing inefficient relaxing of the thermo-ON condition due to temporary state deviations.

Implementation Method 1

a heat-source-side heat exchanger and usage-side heat exchanger for enabling the refrigerant to exchange heat

Methodology Applied
Scientific EffectHeat exchange: Convection

Data Source

PatentEP3059514B1Air-conditioning system and control method therefor
Publication Date: 2019.09.04 DAIKIN INDUSTRIES LTD
  • EP3059514B1 patent drawingFigure 1
  • EP3059514B1 patent drawingFigure 2
  • EP3059514B1 patent drawingFigure 3

AI summary

An air conditioning system having a plurality of indoor units disposed in the same indoor space, wherein the efficiency of the entire air conditioning system is improved. A plurality of indoor units are installed in the same indoor space, the indoor units include respective indoor heat exchangers (42, 52, 62), and the indoor units are capable of setting set temperatures individually. An outdoor unit (20) includes an outdoor heat exchanger (23) for conducting heat exchange with refrigerant circulating in the indoor heat exchangers (42, 52, 62). Indoor-side control devices (47, 57, 67) perform temperature control of the same indoor space for each indoor unit, using a thermo-ON condition set in advance in accordance with the set temperatures, and relax the thermo-ON condition of thermo-OFF indoor units when the indoor units include both those that are thermo-ON and those that are thermo-OFF and a predetermined condition is satisfied.