Multi-room air conditioner

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Solution Overview

Problem

Existing multi-room air-conditioning systems face issues with increased pressure loss in outdoor-unit-side heat exchangers during heating operations due to unnecessary gas refrigerant flow, and inability to perform simultaneous cooling and heating across indoor units.

Innovation Solution

A multi-room air-conditioning apparatus with a four-way switching valve, a second gas-liquid separating device, and a relay unit that bypasses unnecessary gas refrigerant, ensuring only liquid refrigerant flows through the outdoor-unit-side heat exchanger, and allows for selective operation modes including cooling and heating across indoor units.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a two-phase refrigerant flows into the outdoor-unit-side heat exchanger during heating operation, then the heat exchange function is provided, but the pressure loss in the heat exchanger increases due to unnecessary gas refrigerant flow

Engineering Contradiction:
Improvepressure lossVSAvoidunnecessary gas refrigerant flow
Core Design Contradiction:
Loss of energyVSObject-generated harmful factors

Solution Approach 1:

The patent extracts and removes the unnecessary gas refrigerant from the two-phase refrigerant flow before it enters the outdoor-unit-side heat exchanger. A gas-liquid separating device is installed on the inlet side of the heat exchanger to separate gas refrigerant from liquid refrigerant, and only the liquid refrigerant is supplied to the heat exchanger, thereby eliminating the pressure loss caused by gas refrigerant flow.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The gas-liquid separating device acts as an intermediary component between the refrigerant source and the outdoor-unit-side heat exchanger. It processes the two-phase refrigerant by separating gas and liquid phases, and selectively directs only the liquid phase to the heat exchanger, thus mediating the harmful effect of gas refrigerant flow.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of energy

If a gas-liquid separating device is provided on the inlet side of the outdoor-unit-side heat exchanger, then the pressure loss is reduced, but the direction of refrigerant flow at the inlet is not constant

Engineering Contradiction:
Improvepressure lossVSAvoidrefrigerant flow direction
Core Design Contradiction:
Loss of energyVSStability of the object's composition

Solution Approach 1:

The patent employs a four-way switching valve to dynamically control and switch the flow direction of the refrigerant based on different operating modes (cooling, heating, simultaneous cooling and heating). This dynamic adjustment ensures that the gas-liquid separating device receives refrigerant in a consistent direction appropriate for each mode, maintaining flow stability while adapting to different operational requirements.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the operational parameters (flow direction, phase state) of the refrigerant based on the selected mode through the four-way switching valve. By adjusting these parameters dynamically, the system ensures optimal refrigerant flow conditions at the inlet of the gas-liquid separating device for each operating mode.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If simultaneous cooling and heating operations are enabled across indoor units, then the system versatility is improved, but the device complexity increases

Engineering Contradiction:
Improvesimultaneous cooling and heating capabilityVSAvoidrelay unit and flow control configuration
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent divides the system into distinct functional segments: the outdoor unit with the four-way switching valve and gas-liquid separating device, the relay unit with multiple flow control devices, and multiple independent indoor units. Each segment can be controlled independently, allowing simultaneous cooling and heating operations in different indoor units while managing system complexity through modular segmentation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The relay unit is designed with multi-functionality to handle various operating modes including cooling, heating, and simultaneous cooling and heating operations. By integrating multiple flow control devices and a four-way switching valve, the relay unit can universally manage different refrigerant flow patterns to serve multiple indoor units with different operational requirements.

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

This configuration reduces pressure loss in the outdoor-unit-side heat exchanger, maintains high refrigerant temperature for efficient compressor performance, and enables simultaneous cooling and heating operations across indoor units.

Implementation Method 1

a heat-source-side gas-liquid separating device that separates a refrigerant into a gas refrigerant and a liquid refrigerant

Methodology Applied
Scientific EffectGas-liquid separation: Centrifugal Separation

Implementation Method 2

an outdoor-unit-side heat exchanger

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 3

at least a compressor

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 4

a four-way switching valve

Methodology Applied
Scientific EffectFluid flow control: Valve

Data Source

PatentEP2860471B1Multi-room air conditioner
Publication Date: 2019.10.16 MITSUBISHI ELECTRIC CORP
  • EP2860471B1 patent drawingFigure 1~2
  • EP2860471B1 patent drawingFigure 3~4
  • EP2860471B1 patent drawingFigure 5~6

AI summary

A multi-room air-conditioning apparatus (100) includes an outdoor unit (101), a relay unit (102) connected to an outdoor unit (1) by first and second connection pipes (21 and 22), and a plurality of indoor units (103) connected to the relay unit (102). The outdoor unit (101) includes a second gas-liquid separating device (14) provided on the suction side of the compressor (1). The suction side of the compressor (1) and the second gas-liquid separating device (14) are connected to each other by a gas-side outlet pipe (26) and a liquid-side outlet pipe (25).