Air conditioning device

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Solution Overview

Problem

Existing air-conditioning apparatuses for buildings face issues with refrigerant leakage into indoor spaces, high energy consumption due to long circulation paths, poor construction ease, high costs, noise, and inefficient energy use, particularly when multiple indoor units are connected.

Innovation Solution

The air-conditioning apparatus incorporates a relay unit that exchanges heat between the refrigerant and a heat medium, reducing the length of pipes and number of connections between outdoor and indoor units, using a refrigerant circuit and a heat medium circuit with check valves and flow switching devices to manage energy efficiently and prevent refrigerant leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If refrigerant is circulated directly to indoor units, then cooling/heating function is achieved, but refrigerant leakage into indoor space occurs

Engineering Contradiction:
ImprovesafetyVSAvoidrefrigerant leakage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a heat medium (water or antifreeze solution) as an intermediary substance that carries thermal energy between the outdoor heat source unit and indoor units. This heat medium circulates through dedicated pipes without mixing with the refrigerant, thereby preventing refrigerant leakage into indoor spaces while still achieving the desired heating or cooling effect. The heat exchanger in the outdoor unit transfers heat between the refrigerant and the heat medium, which then transports this thermal energy to indoor units.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If heat medium circulation path is made long to connect outdoor unit to multiple indoor units, then multiple indoor units can be served, but energy consumption for conveyance increases

Engineering Contradiction:
Improvenumber of indoor unitsVSAvoidconveyance power
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent divides the heat medium circulation system into multiple independent loops, with each loop serving specific indoor units. The outdoor heat source unit contains multiple heat exchangers that can independently exchange heat with heat medium in different circulation paths. This segmentation allows the system to serve multiple indoor units while optimizing the length of each circulation path, thereby reducing the total conveyance power required compared to a single long circulation path.

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If four pipes are arranged to connect outdoor unit to each indoor unit for simultaneous cooling and heating, then flexible operation is achieved, but construction ease deteriorates

Engineering Contradiction:
Improvecooling or heating selectionVSAvoidconstruction ease
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent designs the heat medium circulation pipes to serve dual functions: the same pipes transport heated heat medium for heating operations and cooled heat medium for cooling operations. By implementing flow control mechanisms (such as three-way valves or flow switching devices) in the outdoor heat source unit, the system can redirect heat medium flow to achieve either heating or cooling through the same physical infrastructure, thereby eliminating the need for separate four-pipe systems while maintaining operational flexibility.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Use of energy by moving object

If secondary refrigerant heat exchanger is placed near each indoor unit, then heat exchange efficiency is improved, but refrigerant leakage risk increases

Engineering Contradiction:
Improveheat exchange efficiencyVSAvoidrefrigerant leakage risk
Core Design Contradiction:
Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent places a heat exchanger near each indoor unit that serves as an intermediary interface between the refrigerant circulation system (confined to the outdoor unit) and the heat medium circulation system (distributed to indoor units). This local heat exchanger enables efficient heat transfer from the refrigerant to the heat medium without requiring refrigerant to be present in the indoor unit, thus maintaining heat exchange efficiency while eliminating refrigerant leakage risk in indoor spaces.

Inventive Principle:
Principle #24Intermediary (Mediator)

5Adaptability or versatility

If multiple indoor units are connected to outdoor unit, then system versatility is improved, but energy efficiency deteriorates due to long pipe paths

Engineering Contradiction:
Improvenumber of connected unitsVSAvoidenergy efficiency
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent implements a segmented heat medium circulation architecture where the outdoor heat source unit contains multiple independent heat exchanger circuits. Each heat exchanger can independently exchange heat with heat medium that circulates to specific indoor units. This segmentation allows the system to optimize the circulation path length for each connected indoor unit, reducing total pipe length and energy losses compared to a single long circulation path serving all units.

Inventive Principle:
Principle #1Segmentation

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 enhances safety, reduces energy consumption, improves construction ease, and optimizes energy efficiency by minimizing pipe length and connections, while preventing refrigerant leakage and allowing for flexible operation modes.

Implementation Method 1

a heat exchanger for exchanging heat between the refrigerant and the heat medium

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP2472199B1Air conditioning device
Publication Date: 2020.08.26 MITSUBISHI ELECTRIC CORP
  • EP2472199B1 patent drawingFigure 1~2
  • EP2472199B1 patent drawingFigure 3
  • EP2472199B1 patent drawingFigure 3A

AI summary

To provide an air-conditioning apparatus which achieves improvement of safety and further achieves saving of energy without allowing a refrigerant to circulate in or near an indoor unit. An air-conditioning apparatus 100 is configured such that pipes 5 have a larger inner cross-sectional area per unit capacity than that of refrigerant pipes 4.