Indoor Unit Airflow Control for Refrigerant Leak Dispersion

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Solution Overview

Problem

Traditional air conditioners using flammable refrigerants struggle to prevent local accumulation of leaked refrigerant gas in indoor spaces, especially in larger rooms, due to insufficient air speed from the indoor unit outlets.

Innovation Solution

The air conditioner incorporates a refrigerant gas sensor that triggers air to be blown from the outlets at a minimum air speed or higher, preset according to the rated cooling capacity, utilizing various air blowout modes such as upper outblow, lower outblow, upper/lower outblow, and left/right outblow to effectively prevent refrigerant gas accumulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If air is blown from the outlet at a fixed air volume, then the air conditioner can operate normally, but the air speed may be insufficient to prevent local accumulation of refrigerant gas in large rooms

Engineering Contradiction:
Improverefrigerant gas dispersion effectivenessVSAvoidair speed from outlet
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The patent applies dynamics by making the air speed variable rather than fixed. The control unit adjusts the air speed dynamically based on the detected refrigerant gas concentration level, enabling the system to adapt to different room sizes and leakage scenarios. This resolves the contradiction by allowing high air speed for effective dispersion when needed, while maintaining normal operation at standard air speeds.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of air speed from a fixed value to a variable parameter that can be adjusted according to refrigerant gas concentration. By establishing a relationship between gas concentration and required air speed, the system can optimize the air blowing performance to prevent local accumulation effectively, resolving the insufficiency in large rooms while maintaining normal operation in smaller spaces.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the air conditioner blows wind at high air speed to prevent refrigerant gas accumulation, then dispersion effectiveness improves, but energy consumption increases

Engineering Contradiction:
Improverefrigerant gas dispersion effectivenessVSAvoidenergy consumption of indoor unit
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies partial action by blowing air at high speed only when necessary - specifically when refrigerant gas leakage is detected. The control unit activates high-speed air blowing mode conditionally based on sensor detection, rather than operating continuously at high speed. This resolves the energy contradiction by providing excessive air speed only when needed for safety, while consuming normal energy during regular operation.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The system employs periodic monitoring of refrigerant gas concentration and activates high-speed air blowing only during detected leakage events. This intermittent operation pattern allows the system to maintain low energy consumption during normal periods while providing high dispersion effectiveness when refrigerant leakage occurs, resolving the energy vs. effectiveness contradiction.

Inventive Principle:
Principle #19Periodic action

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 solution ensures sufficient agitation of indoor air, preventing local accumulation of refrigerant gas when leaks occur, by determining the minimum air speed required for each air blowout mode, effectively mitigating the risk of refrigerant gas concentration in indoor spaces.

Implementation Method 1

a refrigerant gas sensor provided in the indoor unit

Methodology Applied
Scientific EffectGas detection:

Implementation Method 2

air is blown from the one or more outlets at a minimum air speed or higher

Methodology Applied
Scientific EffectAir flow:

Implementation Method 3

air is blown from the one or more outlets at a minimum air speed or higher, the minimum air speed being preset in accordance with a rated cooling capacity of the air conditioner

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3228957B1Air conditioner
Publication Date: 2019.07.31 DAIKIN INDUSTRIES LTD
  • EP3228957B1 patent drawingFigure 1
  • EP3228957B1 patent drawingFigure 2
  • EP3228957B1 patent drawingFigure 3

AI summary

When refrigerant gas leaks in an indoor unit, the leaked refrigerant gas locally accumulates in an area of the indoor space. This air conditioner includes an indoor unit having one or more outlets, and an outdoor unit connected to the indoor unit, wherein a flammable refrigerant or a mildly flammable refrigerant is used. The air conditioner includes a refrigerant gas sensor disposed in the indoor unit. When refrigerant gas is detected by the refrigerant gas sensor, a control is performed such that air is blown from the one or more outlets at a minimum air speed or higher, said minimum air speed being preset in accordance with the rated cooling capacity of the air conditioner.