Air Conditioner Refrigerant Sensor Layout for Rapid Leak Detection

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Solution Overview

Problem

Conventional air conditioning apparatuses using flammable refrigerants face challenges in rapidly detecting refrigerant leakage during operation due to dispersion by the blower airflow, which can lead to delayed detection and increased risk of ignition.

Innovation Solution

The placement of refrigerant sensors on the downwind side of the heat exchanger and near the blower, combined with a top-blow-type structure and additional sensors on the bottom surface for operation stoppage scenarios, enhances the detection of flammable refrigerant leakage by concentrating airflow and reducing external atmosphere interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the refrigerant sensor is arranged on the outer surface of the lower section of the casing, then the leakage of flammable refrigerant during operation stoppage can be detected, but the leakage during operation cannot be rapidly detected due to dispersion by blower airflow

Engineering Contradiction:
Improvedetection accuracyVSAvoiddetection time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent divides the detection function into multiple sensors positioned at different locations: a first refrigerant sensor on the downwind side of the heat exchanger for detecting leakage during operation, and a second refrigerant sensor on the outer surface of the lower section for detecting leakage during operation stoppage. This segmentation allows each sensor to specialize in detecting leakage under specific operational conditions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first refrigerant sensor is pre-positioned on the downwind side of the heat exchanger, which is the location where leaked refrigerant would be carried by the blower airflow during operation. This preliminary positioning ensures that the sensor is already in the optimal detection position when leakage occurs, enabling rapid detection without delay.

Inventive Principle:
Principle #10Preliminary action

2Loss of time

If the first refrigerant sensor is arranged on the downwind side of the heat exchanger, then the leakage during operation can be rapidly detected, but the leakage during operation stoppage cannot be detected by the first sensor

Engineering Contradiction:
Improvedetection timeVSAvoiddetection coverage
Core Design Contradiction:
Loss of timeVSAdaptability or versatility

Solution Approach 1:

The patent implements a multi-functional detection system where the first refrigerant sensor on the downwind side primarily detects leakage during operation, while the second refrigerant sensor on the lower section detects leakage during operation stoppage. Together, these sensors provide universal detection coverage across all operational states, making the system adaptable to both operating conditions.

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

3Measurement precision

If the refrigerant sensor is positioned to detect leaked refrigerant, then the precision of detection is improved, but the sensor is influenced by the atmosphere outside the casing where refrigerant is dispersed

Engineering Contradiction:
Improvedetection precisionVSAvoidexternal atmosphere interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent uses the blower airflow as an intermediary mechanism to transport leaked refrigerant from the heat exchanger area to the downwind side where the first refrigerant sensor is positioned. This intermediary approach concentrates the refrigerant in a controlled path, reducing the influence of external atmosphere dispersion and improving detection precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 allows for rapid and precise detection of refrigerant leaks during both operation and stoppage, reducing the risk of ignition by ensuring timely dispersion of the refrigerant away from the heat exchanger.

Implementation Method 1

a first refrigerant sensor for detecting the flammable refrigerant is provided on the downwind side of a heat exchanger inside the casing

Methodology Applied
Scientific EffectGas concentration detection:

Implementation Method 2

the flammable refrigerant is dispersed by the flow of an air from a blower during an operation of the air conditioning apparatus

Methodology Applied
Scientific EffectForced convection: Forced Convection

Implementation Method 3

when the flammable refrigerant has leaked during the operation stoppage, the flammable refrigerant, which has a high specific gravity, accumulates in the vicinity of the bottom surface section of the casing

Methodology Applied
Scientific EffectGravitational settling: Gravitation

Data Source

PatentEP3115716B1Air conditioning device
Publication Date: 2019.07.17 DAIKIN INDUSTRIES LTD
  • EP3115716B1 patent drawingFigure 1
  • EP3115716B1 patent drawingFigure 2
  • EP3115716B1 patent drawingFigure 3

AI summary

The present invention makes it possible to rapidly detect a leakage of a flammable refrigerant during an operation in an air conditioning apparatus that uses the flammable refrigerant. An air conditioning apparatus (1) is provided with: a casing (71) having an intake port (73a, 74a, 76a), and a discharge port (72a) formed in a top surface section; and a heat exchanger (23) and a blower (36) housed in the casing (71). A first refrigerant sensor (37) for detecting the flammable refrigerant is provided on a downwind side of the heat exchanger (23) inside the casing (71).