Relay Unit Layout for Leak-Safe Multi-Indoor Air Conditioning

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Solution Overview

Problem

Conventional air-conditioning systems for buildings face issues with refrigerant leakage and energy inefficiency, particularly when conveying refrigerant to multiple indoor units, leading to potential room contamination and high power consumption.

Innovation Solution

The system employs a configuration with an outdoor unit, a main relay unit, and sub relay units, where refrigerant is separated into gas and liquid and conveyed to sub relay units, which then exchange heat with a heat medium like water or brine, preventing direct refrigerant circulation indoors and reducing energy consumption by shortening conveyance distances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If refrigerant is circulated directly to multiple indoor units, then cooling and heating operations can be performed, but refrigerant leakage into indoor spaces occurs

Engineering Contradiction:
Improvecooling and heating operationVSAvoidrefrigerant leakage into indoor space
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a heat medium (water or brine) as an intermediary substance between the outdoor unit and indoor units. The refrigerant exchanges heat with the heat medium in the outdoor unit, and the heat medium is then circulated to indoor units through heat medium circulation devices. This intermediary approach allows the refrigerant to remain confined to the outdoor unit while still achieving cooling and heating functions in indoor spaces.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If heat medium is conveyed to indoor units located at long distances, then indoor units can be connected, but power consumption increases

Engineering Contradiction:
Improveconnection of indoor unitsVSAvoidpower consumption
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent divides the indoor units into multiple groups, with each group served by a separate heat medium circulation device. This segmentation allows each circulation device to serve a localized area, reducing the total conveyance distance for heat medium and thereby lowering power consumption compared to a single centralized circulation system serving all indoor units.

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If refrigerant is used for both cooling and heating operations, then system versatility is achieved, but refrigerant leakage risk increases

Engineering Contradiction:
Improvecooling and heating operationVSAvoidrefrigerant leakage prevention
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The heat medium serves as an intermediary that carries thermal energy between the outdoor unit and indoor units. The outdoor unit performs both cooling and heating operations by exchanging heat between the refrigerant and heat medium, and then the heat medium is circulated to indoor units. This approach maintains system versatility while improving reliability by keeping the refrigerant confined to the outdoor unit where leakage can be better controlled.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 prevents refrigerant leakage into indoor spaces and reduces energy consumption by optimizing heat exchange and conveyance power, allowing for efficient cooling and heating operations across multiple indoor units.

Implementation Method 1

a heat exchanger that exchanges heat between the refrigerant and a heat medium such as water or brine

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

a gas-liquid separator that separates the refrigerant into a gas phase and a liquid phase

Methodology Applied
Scientific EffectPhase separation: Phase Change

Data Source

PatentEP2495514B1Air conditioning device
Publication Date: 2019.08.28 MITSUBISHI ELECTRIC CORP
  • EP2495514B1 patent drawingFigure 1
  • EP2495514B1 patent drawingFigure 2
  • EP2495514B1 patent drawingFigure 3

AI summary

An air-conditioning apparatus including an outdoor unit 1 having a compressor 10 compressing a refrigerant and a heat source side heat exchanger 12 exchanging heat between the refrigerant and air; a plurality of indoor units 3 having use side heat exchangers exchanging heat between a heat medium that flows therein and air; and a relay unit disposed between the outdoor unit 1 and the indoor units 3, the relay unit exchanging heat between the refrigerant conveyed from the outdoor unit 1 and the heat medium flowing in the indoor units, in which the relay unit includes a main relay unit 2a that is connected to the outdoor unit1 with two pipings and a sub relay unit 2a-1 that is connected to the main relay unit 2a with three pipings.