Air conditioner

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Solution Overview

Problem

The refrigerant gas sensor in air conditioners using flammable refrigerants may deteriorate upon contact, leading to improper detection of gas leakage if not replaced, causing the system to continue operating with a faulty sensor.

Innovation Solution

Incorporating a controlling unit that stops the compressor when a refrigerant gas sensor detects leakage and requires abnormality cancellation through a special operation using a controller before restarting, ensuring the sensor is replaced before resuming operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the air conditioner allows automatic restart after compressor stoppage, then operational convenience is improved, but safety deteriorates due to continued operation with deteriorated sensor

Engineering Contradiction:
Improveautomatic restart convenienceVSAvoidsensor detection reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system performs preliminary detection of sensor status before allowing restart. The controlling unit checks whether the refrigerant gas sensor is functioning properly after compressor stoppage, and only permits automatic restart if the sensor is confirmed to be operational. This preliminary check prevents restart with deteriorated sensors while maintaining ease of operation for valid cases.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements feedback control by continuously monitoring sensor status and using this information to control restart behavior. The controlling unit receives feedback from the refrigerant gas sensor about its own operational status and adjusts the restart permission accordingly, enabling automatic restart when safe and preventing it when the sensor is deteriorated.

Inventive Principle:
Principle #23Feedback

2Reliability

If the air conditioner requires manual abnormality cancellation, then safety is improved by preventing operation with deteriorated sensor, but operational convenience deteriorates

Engineering Contradiction:
Improvesensor detection reliabilityVSAvoidrestart convenience
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The system applies partial manual intervention by requiring abnormality cancellation only when the sensor is deteriorated, while maintaining automatic restart for normal cases. This selective approach ensures safety is improved for problematic cases without unnecessarily complicating normal operation, balancing reliability and ease of operation.

Inventive Principle:
Principle #16Partial or excessive action

3Productivity

If the refrigerant gas sensor continues to operate after detecting leakage, then productivity is improved, but harmful factors increase due to sensor deterioration

Engineering Contradiction:
Improvecontinuous operation capabilityVSAvoidsensor deterioration
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The system takes preliminary action to prevent sensor deterioration by detecting sensor status changes and stopping the compressor before significant deterioration occurs. The controlling unit monitors sensor performance and halts operation when degradation is detected, preventing the harmful effects of continued operation with deteriorated sensors while maintaining productivity when the sensor is functional.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3249311B1Air conditioner
Publication Date: 2019.12.04 DAIKIN INDUSTRIES LTD
  • EP3249311B1 patent drawingFigure 1
  • EP3249311B1 patent drawingFigure 2
  • EP3249311B1 patent drawingFigure 3

AI summary

An air conditioner which continues driving with a deteriorated gas leakage sensor is provided. An air conditioner of the present invention includes an outdoor unit including a compressor and an indoor unit connected with the outdoor unit and uses flammable refrigerant. The air conditioner includes: a refrigerant gas sensor; and a controlling unit configured to stop the compressor at occurrence of abnormality, when the refrigerant gas sensor detects refrigerant gas while the compressor is being driven. After the compressor is stopped as the refrigerant gas sensor detects the refrigerant gas, the controlling unit does not start driving of the compressor until an operation to cancel the abnormality is performed.