Indoor Airflow Control for Refrigerant Leak Diffusion

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Solution Overview

Problem

Conventional air-conditioning apparatuses may inadvertently blow leaked flammable refrigerant to areas with ignition appliances, potentially leading to flammable areas when the appliances are turned on, as they do not effectively diffuse the refrigerant in cases of leakage.

Innovation Solution

An indoor unit with a casing, airflow direction adjusting members, an indoor heat exchanger, a blower device, and a refrigerant leakage sensor, controlled by a controller to alter airflow direction and increase blower operation upon detecting refrigerant leakage, ensuring diffusion and preventing flammable area formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If refrigerant leakage is detected and air is supplied to areas without heat sources, then refrigerant diffusion is improved, but the risk of forming flammable areas in other locations increases

Engineering Contradiction:
Improverefrigerant diffusion effectivenessVSAvoidflammable area formation risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Instead of supplying air to areas without heat sources (conventional approach), the invention inverts the approach by supplying air specifically to areas WHERE heat sources ARE provided. This inversion resolves the contradiction because heat sources act as natural diffusion points that prevent refrigerant accumulation, thereby eliminating the flammable area formation risk while maintaining effective refrigerant diffusion.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The invention converts the potentially harmful heat sources into beneficial diffusion points. By directing air supply to locations with heat sources, the refrigerant is利用ized to diffuse through areas where thermal energy already exists, turning what could be ignition risks into effective diffusion zones that prevent hazardous accumulation.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Reliability

If air is supplied to diffuse refrigerant, then refrigerant concentration is reduced, but energy consumption increases

Engineering Contradiction:
Improverefrigerant diffusionVSAvoidblower device energy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The invention applies local quality by directing air supply selectively to specific locations (areas with heat sources) rather than uniformly throughout the space. This localized approach reduces the total volume of air that needs to be moved, thereby lowering blower device energy consumption while maintaining effective refrigerant diffusion at the critical zones.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention changes the parameter of air supply location from general/distributed to specific/targeted areas with heat sources. This parameter change optimizes the balance between diffusion effectiveness and energy consumption by concentrating air supply where it is most needed and where heat sources can facilitate further diffusion.

Inventive Principle:
Principle #35Parameter changes

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

Effectively diffuses leaked refrigerant to prevent flammable area formation, even when the ignition appliance is turned on, by adjusting airflow direction and increasing blower speed, thus ensuring safety and suppressing the risk of ignition.

Implementation Method 1

a refrigerant leakage sensor disposed in the air passage of the casing and configured to detect refrigerant leakage

Methodology Applied
Scientific EffectGas detection:

Implementation Method 2

an indoor blower device disposed in the air passage of the casing and configured to supply air to the indoor heat exchanger

Methodology Applied
Scientific EffectForced convection: Forced Convection

Implementation Method 3

an airflow direction adjusting member having a plate shape, disposed at the air outlet of the casing, and configured to change a direction of air blowing from the air outlet

Methodology Applied
Scientific EffectFlow direction control:

Implementation Method 4

an indoor heat exchanger disposed in the air passage of the casing

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP3150943B1Air conditioning apparatus including indoor unit and outdoor unit
Publication Date: 2019.03.27 MITSUBISHI ELECTRIC CORP
  • EP3150943B1 patent drawingFigure 1~2
  • EP3150943B1 patent drawingFigure 3
  • EP3150943B1 patent drawingFigure 4~6

AI summary

An indoor unit of an air-conditioning apparatus includes: a casing including an air inlet, an air outlet, and an air passage extending from the air inlet to the air outlet; an airflow direction adjusting member having a plate shape, disposed at the air outlet of the casing, and configured to change a direction of air blowing from the air outlet; an indoor heat exchanger disposed in the air passage of the casing; an indoor blower device disposed in the air passage of the casing and configured to supply air to the indoor heat exchanger; a refrigerant leakage sensor disposed in the air passage of the casing and configured to detect refrigerant leakage; and a controller configured to rotate the airflow direction adjusting member and cause the indoor blower device to operate when determining that refrigerant leakage is present based on a detection result of the refrigerant leakage sensor.