Multi-Floor Air Conditioning Layout for Refrigerant Leak Isolation

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Solution Overview

Problem

Existing air-conditioning systems face challenges with refrigerant leakage, particularly for high-pressure refrigerants like R410A, which have significant global warming coefficients, and natural refrigerants like carbon dioxide, ammonia, and propane, which require stringent leakage control due to safety and environmental concerns, while also incurring high energy consumption in chiller systems.

Innovation Solution

The air-conditioning apparatus features a heat source device, a relay unit, and an indoor unit connected by refrigerant and heat medium pipelines, with the relay unit located in a non-living space to separate the heat-source side refrigerant from the living space, using a secondary refrigerant like water or brine to reduce energy consumption and enhance safety by minimizing refrigerant leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a high-pressure refrigerant is conveyed to an indoor unit, then cooling or heating operation is achieved, but the refrigerant filled amount becomes extremely large and refrigerant leakage risk increases

Engineering Contradiction:
Improverefrigerant leakage preventionVSAvoidrefrigerant filled amount
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The refrigerant circuit is divided into two separate circuits: a heat source device side refrigerant circuit containing the compressor and first heat exchanger, and a load side refrigerant circuit containing the indoor units. These circuits are connected via a heat medium circuit, creating a segmentation that isolates the high-pressure refrigerant from the indoor living spaces, thereby reducing the refrigerant filled amount in each segment and preventing leakage into living areas.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A heat medium (water or brine) is introduced as an intermediary substance between the heat source device and the indoor units. The heat medium circulates through a pump and heat exchangers to transfer thermal energy, replacing the direct high-pressure refrigerant conveyance. This intermediary approach eliminates the need for large amounts of high-pressure refrigerant in the distribution system while maintaining effective cooling and heating operations.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Use of energy by stationary object

If heat exchange is performed between refrigerant and water in the heat source device, then cooling or heating energy is transferred to indoor units, but water conveying power becomes extremely large and energy consumption increases

Engineering Contradiction:
Improveenergy consumptionVSAvoidwater conveying power
Core Design Contradiction:
Use of energy by stationary objectVSPower

Solution Approach 1:

The system optimizes the operating parameters of the heat medium circulation, including temperature differences and flow rates, to minimize the power consumption of the pump. By carefully controlling these parameters and selecting appropriate heat exchanger configurations, the system achieves efficient heat transfer without requiring excessive water conveying power, thereby reducing overall energy consumption.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the relay unit is located on a floor separated from the heat source device by plural floors, then refrigerant leakage into living space is suppressed, but installation complexity increases

Engineering Contradiction:
Improverefrigerant leakage suppressionVSAvoidinstallation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The relay unit is strategically positioned in a non-living space such as a roof, basement, or equipment room, utilizing vertical and horizontal spatial dimensions to separate the refrigerant-containing components from living areas. This spatial reconfiguration allows the system to suppress refrigerant leakage into living spaces while managing installation complexity through careful planning of the multi-floor layout and pipeline routing.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 effectively suppresses refrigerant leakage into living spaces, improves safety and reliability, and reduces energy consumption by optimizing the refrigerant flow and heat exchange processes, while allowing for efficient installation and maintenance.

Implementation Method 1

a compressor that pressurizes a primary refrigerant used by changing states between a gas phase and a liquid phase or between a supercritical state and a non-supercritical state

Methodology Applied
Scientific EffectPhase change: Phase Change

Implementation Method 2

a first heat exchanger connected to the switching device and is installed outside of a building having a plurality of floors or in a space leading to the outside

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 3

a relay unit having a second heat exchanger that is located on an installed floor separated from the heat source device by plural floors and in a space not to be air-conditioned, and exchanges heat between the primary refrigerant and a secondary refrigerant mainly composed of water or brine

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 4

an indoor unit having a third heat exchanger that exchanges heat between the secondary refrigerant and air in the space to be air-conditioned

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP2309194B1Air conditioner
Publication Date: 2015.08.26 MITSUBISHI ELECTRIC CORP
  • EP2309194B1 patent drawingFigure 1
  • EP2309194B1 patent drawingFigure 1a
  • EP2309194B1 patent drawingFigure 2

AI summary

An air-conditioning apparatus in which entry of a refrigerant into a living space is suppressed and measures against refrigerant leakage are taken is provided. An air-conditioning apparatus 100 is provided with a heat source device 1 halving a compressor that pressurizes a primary refrigerant, a four-way valve 11 that switches a circulation direction of the primary refrigerant, and a heat-source side heat exchanger 12 connected to the four-way valve 11 and installed outside of a building 9 having a plurality of floors or in a space leading to the outside, a relay unit 3 having an intermediate heat exchanger that is disposed in a space not to be air-conditioned different from the space to be air-conditioned on the installed floor separated from the heat source device 1 by plural floors and exchanges heat between the primary refrigerant and a secondary refrigerant and a pump 21 that conveys the secondary refrigerant, an indoor unit 2 having a use-side heat exchanger 26 that exchanges heat between the secondary refrigerant and air in the space to be air-conditioned, a vertical pipeline that connects the heat source device 1 and the relay unit 3 across the plurality of floors, and a horizontal pipeline that connects the relay unit 3 and the indoor unit 2 to each other from outside a wall dividing the space to be air-conditioned to indoors and outdoors and in which the secondary refrigerant in a liquid phase flows through both of pipelines in sets of at least two pipelines.