Grouped Air Conditioning Control for Outdoor Air Cooling

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Solution Overview

Problem

In air conditioning systems with multiple indoor units connected to a single refrigerant circuit, if outdoor air temperature is lower than the set temperature for one group but higher than for others, stopping the indoor unit in the cooler group for outdoor air cooling operation can lead to uncomfortable temperatures in remaining groups due to the compressor being stopped, resulting in inefficient energy use.

Innovation Solution

The system includes a controller that adjusts the refrigerant flow rate using valves in each group, allowing outdoor air cooling operation in one group while keeping the compressor running and maintaining cooling in other groups by controlling the utilization units and ventilators, reducing refrigerant circulation and compressor load, and considering temperature and humidity differences between groups.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the indoor unit is stopped to perform outdoor air cooling operation in one group, then electric power consumption is reduced, but the compressor is stopped causing uncomfortable temperatures in remaining groups

Engineering Contradiction:
Improveelectric power consumptionVSAvoidcooling availability in remaining groups
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The system divides the refrigerant circuit into multiple independent groups, each with its own flow control valve. This allows the compressor to continue operating while refrigerant flow is segmented and directed only to groups requiring cooling, enabling outdoor air cooling in some groups without stopping the compressor, thus maintaining cooling availability in other groups while reducing overall energy consumption.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of stopping the compressor entirely for outdoor air cooling operation, the system applies partial action by controlling refrigerant flow to only the necessary groups through flow control valves. The compressor continues running at reduced load, providing just enough refrigerant to groups that need cooling while allowing outdoor air cooling in other groups, avoiding the excessive action of complete compressor shutdown.

Inventive Principle:
Principle #16Partial or excessive action

2Use of energy by moving object

If the compressor is stopped for outdoor air cooling operation, then electric power consumption is reduced, but cooling operation cannot be performed in any group

Engineering Contradiction:
Improveelectric power consumptionVSAvoidcooling operation capability
Core Design Contradiction:
Use of energy by moving objectVSAdaptability or versatility

Solution Approach 1:

The refrigerant circuit is segmented into multiple groups with independent flow control, allowing the compressor to remain operational while refrigerant is selectively distributed. This segmentation enables the system to maintain cooling capability in groups that need it while performing outdoor air cooling in other groups, avoiding complete loss of cooling versatility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts refrigerant flow distribution based on real-time cooling demands of different groups. The flow control valves respond to temperature conditions and cooling requirements, continuously optimizing refrigerant allocation between groups requiring active cooling and those performing outdoor air cooling, thereby maintaining overall system adaptability.

Inventive Principle:
Principle #15Dynamics

3Use of energy by moving object

If refrigerant flow is reduced for outdoor air cooling operation, then electric power consumption is reduced, but cooling capacity is insufficient for groups requiring cooling

Engineering Contradiction:
Improveelectric power consumptionVSAvoidcooling capacity
Core Design Contradiction:
Use of energy by moving objectVSPower

Solution Approach 1:

Refrigerant flow is segmented and directed to specific groups based on their cooling requirements. Groups requiring active cooling receive adequate refrigerant flow through open flow control valves, maintaining sufficient cooling capacity, while groups performing outdoor air cooling have their flow restricted, reducing overall system power consumption without compromising cooling capacity where needed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system applies local quality by providing different refrigerant flow rates to different groups based on their specific cooling needs. Groups with higher cooling demands receive more refrigerant flow, while groups suitable for outdoor air cooling receive reduced or no refrigerant flow, optimizing the balance between cooling capacity and energy consumption locally in each group.

Inventive Principle:
Principle #3Local quality

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 configuration reduces electric power consumption by allowing outdoor air cooling in specific groups while maintaining comfortable temperatures across all groups, optimizing energy use and reducing refrigerant circulation and compressor load.

Implementation Method 1

The first group includes a valve configured to adjust a flow rate of a refrigerant flowing to the at least one heat exchanger of the first utilization unit

Methodology Applied
Scientific EffectRefrigerant flow control:

Implementation Method 2

The first utilization unit includes a heat exchanger

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 3

a compressor of the outdoor unit may be stopped

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 4

the ventilator can perform outdoor air cooling operation in the first group

Methodology Applied
Scientific EffectAir movement: Fan

Data Source

PatentEP3792565B1Air conditioning system
Publication Date: 2023.06.21 DAIKIN INDUSTRIES LTD
  • EP3792565B1 patent drawingFigure 1
  • EP3792565B1 patent drawingFigure 2
  • EP3792565B1 patent drawingFigure 3

AI summary

Provided is an air conditioning system that enables outdoor air cooling operation to reduce electric power consumption. The air conditioning system includes a plurality of utilization units (12) divided at least into a first utilization unit (12A) belonging to a first group (G1) and a second utilization unit (12B) belonging to a second group (G2), and a ventilator (30) belonging to the first group (G1). In the first group (G1), the utilization unit (12) includes a heat exchanger (26) and a valve (25) to adjust a flow rate of a refrigerant flowing to the at least one heat exchanger (26). When, as to the first group (G1), an outdoor air condition is satisfied for outdoor air, which is air outside an air conditioning target space (Z), a controller (29 or 36) closes the valve (25) and causes the ventilator (30) to perform outdoor air cooling operation in the first group Gl.