Refrigerant Leak Verification Control in Air Conditioning

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Solution Overview

Problem

Conventional air-conditioning systems face issues with false refrigerant leakage detection, leading to unnecessary shutdowns and compromised user comfort, as existing safety measures cannot distinguish between actual and false refrigerant leakage.

Innovation Solution

An air-conditioning apparatus with a refrigerant leakage sensor and a controller that determines the occurrence of refrigerant leakage based on both sensor detection and operating state, allowing the refrigerant circuit cutoff device to be activated only when leakage is confirmed, thereby maintaining operation when no leakage is detected.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a cutoff valve is installed to cut off refrigerant flow upon leakage detection, then refrigerant leakage safety is improved, but false detection causes unnecessary shutdowns and user comfort deteriorates

Engineering Contradiction:
Improverefrigerant leakage safetyVSAvoiduser comfort
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The system performs preliminary verification by checking operating state parameters (compressor status, refrigerant flow conditions) before activating the cutoff valve. This preliminary action distinguishes between actual leakage and false detection signals, preventing unnecessary shutdowns while maintaining safety response capability

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The controller continuously monitors operating state parameters and uses this feedback to verify leakage detection signals. By comparing sensor signals with actual system operating conditions, the system confirms whether detected leakage is real or false, thereby avoiding false-positive cutoff valve activation

Inventive Principle:
Principle #23Feedback

2Measurement precision

If refrigerant leakage detection is made highly sensitive, then detection capability is improved, but false positive detection increases leading to unnecessary shutdowns

Engineering Contradiction:
Improverefrigerant leakage detection capabilityVSAvoiddetection accuracy
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The system uses operating state information as feedback to verify leakage detection signals. By cross-referencing sensor readings with actual compressor operation and refrigerant flow conditions, the system confirms whether detected leakage represents a true hazard or a false alarm, thereby improving detection accuracy without reducing sensitivity

Inventive Principle:
Principle #23Feedback

3Speed

If the air-conditioning apparatus shuts down immediately upon leakage detection, then safety response speed is improved, but false detection causes unnecessary operation stop and user comfort deteriorates

Engineering Contradiction:
Improvesafety response speedVSAvoidoperation continuity
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

Before executing the shutdown action, the system performs preliminary verification by checking operating state parameters. This preliminary check ensures that shutdown is triggered only by actual leakage conditions, maintaining fast response for real hazards while preventing unnecessary shutdowns that would disrupt operation continuity

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts its response based on verified leakage conditions. When leakage is confirmed through operating state verification, immediate shutdown occurs; when false detection is identified, the system maintains operation. This dynamic response optimizes both safety response speed and operation continuity

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3546855B1Air conditioner and air conditioning system
Publication Date: 2020.09.09 MITSUBISHI ELECTRIC CORP
  • EP3546855B1 patent drawingFigure 1~2
  • EP3546855B1 patent drawingFigure 3~4
  • EP3546855B1 patent drawingFigure 5~6

AI summary

An air-conditioning apparatus includes a refrigerant circuit in which a compressor, a heat source heat exchanger, an expansion device, and a load heat exchanger are connected via refrigerant pipes; a refrigerant leakage sensor configured to output a refrigerant leakage detection signal indicating detection of refrigerant leakage when the refrigerant leakage sensor detects the refrigerant leakage; a refrigerant leakage cutoff device configured to cut off a flow of refrigerant when the refrigerant leakage cutoff device is set to a closed state; and a controller configured to determine whether refrigerant leakage occurs on the basis of an operating state and whether the refrigerant leakage detection signal is received from the refrigerant leakage sensor. When the controller receives the refrigerant leakage detection signal and determines, on the basis of the operating state, that the refrigerant leakage occurs, the controller is configured to set the refrigerant leakage cutoff device to the closed state.