Dual-Sensor Refrigerant Leak Detection in Flammable Air Conditioners

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Solution Overview

Problem

Conventional air conditioners fail to detect refrigerant leaks accurately as they do not account for the simultaneous leakage of refrigeration oil, which poses a safety risk.

Innovation Solution

The air conditioner incorporates both a refrigerant sensor and an odor sensor to detect refrigerant leaks by monitoring the concentration of refrigerant and the odor of refrigeration oil, enabling more precise leak detection and improved safety measures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If only a refrigerant sensor is used for leak detection, then the device complexity is low, but the measurement precision of refrigerant leak detection is insufficient

Engineering Contradiction:
Improverefrigerant leak detection accuracyVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The detection function is segmented into two separate sensors: a refrigerant sensor for detecting refrigerant concentration and an odor sensor for detecting refrigeration oil odor. This segmentation allows each sensor to specialize in detecting its target substance, improving overall detection accuracy while maintaining manageable system complexity through functional division.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The odor sensor serves multiple purposes: it detects refrigeration oil leaks, confirms refrigerant leaks (since refrigeration oil leaks accompany refrigerant leaks), and provides backup detection capability. This multi-functionality improves measurement precision without proportionally increasing device complexity.

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

2Reliability

If refrigeration oil leakage is not considered in the detection system, then the device complexity remains low, but the reliability of safety detection deteriorates

Engineering Contradiction:
Improvesafety detection reliabilityVSAvoiddetection system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The odor sensor acts as an intermediary indicator for refrigeration oil leakage. Since refrigeration oil leaks occur simultaneously with refrigerant leaks, detecting the odor of refrigeration oil provides indirect but reliable confirmation of refrigerant leak events, improving safety detection reliability without requiring direct monitoring of refrigeration oil concentration.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The odor sensor provides feedback information about refrigeration oil presence, which complements the refrigerant sensor data. This feedback mechanism enhances the reliability of leak detection by providing corroborating evidence from a different detection modality, ensuring that safety alerts are based on multiple independent measurements.

Inventive Principle:
Principle #23Feedback

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 dual-sensor approach enhances the accuracy of refrigerant leak detection, ensuring improved safety by addressing the issue of refrigeration oil leakage alongside refrigerant leaks, and can operate even during power failures without additional power supplies.

Implementation Method 1

an odor sensor that detects an odor of the refrigeration oil

Methodology Applied
Scientific EffectOdor detection:

Data Source

PatentEP3961119B1Air conditioner
Publication Date: 2024.01.31 MITSUBISHI ELECTRIC CORP
  • EP3961119B1 patent drawingFigure 1~2
  • EP3961119B1 patent drawingFigure 3
  • EP3961119B1 patent drawingFigure 4~5

AI summary

In an air conditioner (100) according to an aspect of the present invention, flammable refrigerant circulates in order of a compressor (3), a first heat exchanger (1), an expansion valve (5), and a second heat exchanger (6). The compressor (3) stores refrigeration oil and discharges the refrigeration oil with the refrigerant. The refrigeration oil circulates with the refrigerant in order of the compressor (3), the first heat exchanger (1), the expansion valve (5), and the second heat exchanger (6). The first heat exchanger (1) is located in a first space. The second heat exchanger (6) is located in a second space. The air conditioner (100) includes a first sensor (s1), a second sensor (s2), and a controller (8). The first sensor (s1) detects the refrigerant in the first space. The second sensor (s2) detects an odor of the refrigeration oil in the first space. The controller (8) detects a leak of the refrigerant using a first detection signal from the first sensor (s1) and a second detection signal from the second sensor (s2).