Air-conditioning device and operation control device

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Solution Overview

Problem

Air-conditioning apparatuses that reuse existing pipes face increased pressure anomalies and reliability issues during high outside air temperature environments due to reduced indoor unit load capacity, leading to higher refrigerant pressures exceeding the pressure-withstanding reference value.

Innovation Solution

The air-conditioning apparatus adjusts the opening degree of the heat source-side pressure reducing device based on the reduction in total load capacity to maintain refrigerant pressure within the pressure-withstanding reference value, using a controller to manage the compressor frequency and solenoid valve operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the load capacity of indoor units is reduced during cooling operation in high outside air temperature environment, then the cooling demand is matched to actual load, but the refrigerant pressure in existing pipes increases and may exceed the pressure-withstanding reference value

Engineering Contradiction:
Improvecooling operation efficiencyVSAvoidsystem reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The control device continuously monitors the total load capacity of indoor units and dynamically adjusts the opening degree of the heat source-side pressure reducing device based on this feedback. When load capacity decreases, the control device reduces the opening degree to maintain refrigerant pressure within safe limits, preventing abnormal stops while adapting to actual cooling demands

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The invention changes the opening degree parameter of the heat source-side pressure reducing device in response to load capacity changes. By adjusting this parameter dynamically based on actual load conditions, the system maintains pressure within acceptable ranges while optimizing cooling performance for varying load requirements

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the opening degree of heat source-side pressure reducing device is adjusted according to load capacity reduction, then refrigerant pressure is controlled to remain at or below the pressure-withstanding reference value, but the system complexity increases

Engineering Contradiction:
Improvepressure control reliabilityVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The control device automatically monitors load capacity changes and self-adjusts the opening degree of the pressure reducing device without requiring manual intervention. The system serves itself by detecting pressure trends and autonomously modifying valve opening to maintain safe operating parameters, reducing the need for complex external control mechanisms

Inventive Principle:
Principle #25Self-service

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 solution reduces the frequency of abnormal stops caused by pressure anomalies, ensuring a reliable air-conditioning system by controlling refrigerant pressure and maintaining system stability during high outside air temperature conditions.

Implementation Method 1

a heat source-side pressure reducing device 4, which reduces a pressure of the refrigerant

Methodology Applied
Scientific EffectPressure reduction: Pressure Drop

Data Source

PatentEP3306214B1Air-conditioning device and operation control device
Publication Date: 2023.10.18 MITSUBISHI ELECTRIC CORP
  • EP3306214B1 patent drawingFigure 1
  • EP3306214B1 patent drawingFigure 2
  • EP3306214B1 patent drawingFigure 3

AI summary

An air-conditioning apparatus (1) includes a controller (500) (operation control device). During a cooling operation, when an outside air temperature of outdoor air supplied to a heat source-side heat exchanger (3) exceeds a reference outside air temperature, and when a total load capacity of at least one load-side unit (first load-side unit 200a and/or second load-side unit 200b) is reduced over time, the controller (500) (operation control device) adjusts an opening degree of a pressure reducing device (heat source-side pressure reducing device 4) in accordance with a reduction amount of the total load capacity.