Wall-Mounted Indoor Unit Leak Sensor Placement for Flammable Refrigerant

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Solution Overview

Problem

Existing air conditioners using flammable refrigerants face challenges in reliably detecting refrigerant leaks within indoor units, which can pose safety risks due to the flammability of these refrigerants.

Innovation Solution

The air conditioner incorporates a leak detection sensor positioned on the exterior bottom part of the indoor unit, leveraging the Coanda effect to enhance the detection of refrigerant leaks by guiding the leaking refrigerant along the surface where the sensor can effectively detect it, thereby improving the reliability of leak detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the leak detection sensor is positioned inside the indoor unit, then the device complexity is reduced, but the measurement precision of refrigerant leak detection deteriorates

Engineering Contradiction:
Improverefrigerant leak detection precisionVSAvoidsensor positioning complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The leak detection sensor is extracted from the interior of the indoor unit and repositioned on the exterior bottom surface. This extraction allows the sensor to be positioned where refrigerant naturally accumulates during a leak, improving detection precision without adding internal complexity to the unit structure

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The exterior bottom surface of the indoor unit serves as an intermediary positioning platform for the leak detection sensor. This location acts as an optimal detection point where refrigerant accumulates during leaks, enabling effective monitoring without requiring the sensor to be embedded within the unit's internal structure

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the leak detection sensor is positioned on the exterior bottom part of the indoor unit, then the reliability of refrigerant leak detection is improved, but the device complexity increases

Engineering Contradiction:
Improverefrigerant leak detection reliabilityVSAvoidsensor positioning complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The sensor is extracted from conventional internal positions and relocated to the exterior bottom surface, leveraging the natural accumulation behavior of refrigerant during leaks. This simple repositioning significantly improves detection reliability by placing the sensor where refrigerant concentration is highest during a leak event

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system utilizes the natural physical behavior of refrigerant (accumulation on bottom surfaces due to gravity and density) to guide sensor placement. The refrigerant essentially 'services' the detection process by naturally directing itself to the sensor location, eliminating the need for complex active transport or detection mechanisms

Inventive Principle:
Principle #25Self-service

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 significantly enhances the reliability of refrigerant leak detection, ensuring timely and accurate identification of leaks, even for flammable refrigerants like R290, which are prone to flowing along the unit's exterior surfaces due to their specific gravity, thus preventing the formation of high-concentration areas within the room.

Implementation Method 1

leveraging the Coanda effect to enhance the detection of refrigerant leaks by guiding the leaking refrigerant along the surface where the sensor can effectively detect it

Methodology Applied
Scientific EffectCoanda effect: Coanda Effect

Data Source

PatentEP4464947A1Air conditioner
Publication Date: 2024.11.20 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP4464947A1 patent drawingFigure 1
  • EP4464947A1 patent drawingFigure 2
  • EP4464947A1 patent drawingFigure 3

AI summary

An air conditioner according to the present disclosure includes: an outdoor unit; indoor unit (30) of a wall-mounted type attached to a wall surface in a room; and a refrigeration cycle circuit filled with a flammable refrigerant, indoor unit (30) including leak detection sensor (39) that detects a leak of the flammable refrigerant, leak detection sensor (39) being provided on exterior bottom part (35b) of indoor unit (30).