Refrigerant leakage determination system

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Solution Overview

Problem

Existing refrigerant leakage determination systems can erroneously determine a leak when none has occurred, leading to inaccurate results.

Innovation Solution

A refrigerant leakage determination system with a first determination unit that uses a first state amount, such as the degree of subcooling, and a second determination unit that verifies the result using different information, such as sensor failures or refrigerant accumulation, to reduce erroneous determinations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single determination unit is used to detect refrigerant leakage, then the device complexity is low, but the measurement precision and reliability of leakage detection deteriorate due to erroneous determinations

Engineering Contradiction:
Improvedetermination system structureVSAvoidrefrigerant leakage detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The determination system is segmented into multiple independent determination units, each analyzing different parameters (condenser outlet temperature, suction temperature, discharge temperature, degree of subcooling). This segmentation allows cross-verification of results, reducing erroneous determinations while maintaining manageable system complexity through modular architecture

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system implements feedback mechanisms where determination results from multiple units are aggregated and verified. The control unit receives inputs from all determination units and applies logical verification (e.g., requiring multiple units to agree on leakage presence), creating a feedback loop that improves detection accuracy by eliminating false positives

Inventive Principle:
Principle #23Feedback

2Reliability

If multiple determination units are used to verify leakage detection, then the measurement precision and reliability improve, but the device complexity increases

Engineering Contradiction:
Improvedetermination result accuracyVSAvoiddetermination system structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system divides the determination function into separate units, each responsible for analyzing specific temperature parameters. This segmentation improves reliability through diversified analysis while controlling complexity by assigning clear, limited responsibilities to each unit

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple determination units are merged into a unified control unit that aggregates their results. The control unit combines individual determinations using logical operations (e.g., AND/OR logic based on which units detect leakage), achieving high reliability through result verification while managing complexity through centralized result processing

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If degree of subcooling is used as determination index, then the measurement precision of leakage detection improves, but the device complexity increases due to additional temperature measurement requirements

Engineering Contradiction:
Improverefrigerant leakage detection accuracyVSAvoidsensor configuration
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The temperature sensors serve multiple functions: they are used both for calculating the degree of subcooling (improving leakage detection precision) and for other system control functions. This multi-functionality allows the system to benefit from enhanced detection accuracy without the penalty of dedicated additional sensors, thus controlling device complexity

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

Data Source

PatentEP4015945B1Refrigerant leakage determination system
Publication Date: 2025.07.09 DAIKIN INDUSTRIES LTD
  • EP4015945B1 patent drawingFigure 1
  • EP4015945B1 patent drawingFigure 2
  • EP4015945B1 patent drawingFigure 3

AI summary

A refrigerant leakage determination system (1) includes a refrigerant circuit (10), a first determination unit (60), and a second determination unit (70). The refrigerant circuit (10) includes a compressor (21), a condenser (24, 52a), an expansion mechanism (25, 51a), and an evaporator (52a, 24). The first determination unit (60) determines that refrigerant has leaked from the refrigerant circuit (10), by using a first state amount of refrigerant as a determination index, the first state amount including at least one of an outlet temperature of the condenser, a suction temperature of the compressor, and a discharge temperature of the compressor. The second determination unit (70) determines that refrigerant has leaked from the refrigerant circuit (10), based on information different from the first state amount.