Heat-Medium Air Conditioning Layout for Leak-Safe Refrigerant Use

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Solution Overview

Problem

Conventional air-conditioning apparatuses for building use face issues such as refrigerant leakage safety concerns, inefficient energy consumption due to long heat medium circulation paths, and impractical systems with noise and high costs due to the need for pumps at every indoor unit, limiting the use of flammable refrigerants and optimal operation efficiency.

Innovation Solution

The air-conditioning apparatus connects multiple refrigerant circuits to a heat medium circulation circuit, allowing for individual refrigerant circuits to provide cooling and heating capacity, which can be shared, and includes a refrigerant flow path switching device and heat exchangers to optimize operation efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If refrigerant is circulated to indoor unit in conventional multi-air-conditioning apparatus, then cooling or heating can be performed, but refrigerant leakage safety concern arises

Engineering Contradiction:

ImprovesafetyVSAvoidrefrigerant leakage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system separates the refrigerant circulation system (outdoor unit only) from the heat medium circulation system (indoor units). The refrigerant remains confined to the outdoor unit while heat exchangers transfer thermal energy to/from the refrigerant, and separate heat medium circuits deliver this energy to indoor units. This segmentation eliminates refrigerant leakage risks in indoor spaces while maintaining air conditioning functionality.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If heat medium circulation path is made long to transport heat from outdoor heat source unit, then air-conditioning can be provided to multiple indoor units, but energy consumption by transportation power becomes significantly larger

Engineering Contradiction:

Improveservice coverageVSAvoidenergy consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

Heat exchangers are installed at each indoor unit location, enabling localized heat transfer. Each indoor unit has its own heat exchanger that directly exchanges heat with the refrigerant in the outdoor unit through heat conduction via the building structure (e.g., through walls or floors). This eliminates the need for long-distance heat medium transportation and associated energy losses, while still providing service to multiple indoor units.

Inventive Principle:

Principle #3Local quality

3Loss of energy

If flammable refrigerant is used to reduce global warming potential, then environmental performance improves, but safety concern prevents its use due to leakage risk

Engineering Contradiction:

Improveglobal warming potentialVSAvoidsafety

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

By segmenting the system so that flammable refrigerant is confined exclusively to the outdoor unit with no direct connection to indoor spaces, the invention enables the use of environmentally friendly flammable refrigerants. The refrigerant circulation path is separated from occupied indoor areas, eliminating safety concerns while allowing the benefits of low global warming potential refrigerants to be realized.

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 operational efficiency, reduces energy consumption, and allows for the use of flammable refrigerants while preventing indoor leakage, achieving optimized and energetically efficient air-conditioning performance.

Implementation Method 1

heat exchangers related to heat medium which exchange heat between the refrigerant and heat medium different from the refrigerant

Methodology Applied

Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

compressor for compressing a refrigerant

Methodology Applied

Scientific EffectCompression: Compression

Implementation Method 3

expansion device for adjusting the pressure of the refrigerant

Methodology Applied

Scientific EffectPressure adjustment: Pressure Drop

Data Source

PatentEP2549201B1Air conditioning device

Publication Date: 2019.12.25 MITSUBISHI ELECTRIC CORP

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AI summary

To obtain an apparatus which can further improve operation efficiency in an air-conditioning apparatus which performs heat exchange between a refrigerant and a heat medium and performs air-conditioning with the heat medium. The apparatus includes refrigerating cycle systems each connecting a compressor 10 for compressing a refrigerant, a refrigerant flow path switching device 11 for switching the circulation path of the refrigerant, a heat source side heat exchanger 12 for exchanging heat for the refrigerant, an expansion device 16 for adjusting the pressure of the refrigerant, and heat exchangers 15 related to heat medium which exchanges heat between the refrigerant and heat medium different from the refrigerant to be able to make the heat medium different in temperature respectively, by piping 4 so as to constitute refrigerant circuits; and heat medium side systems each connecting pumps 21 for circulating the heat medium for the heat exchangers 15 related to heat medium, use side heat exchangers 26 for exchange heat between the heat medium and air of an air-conditioning target space and heat medium flow switching systems 22,23 for switching the heat medium which passes through each heat exchangers 15 related to heat medium to each use side heat exchanger 26, by piping 5 so as to constitute a heat medium circulation circuit.