Diagnostic for refrigerant composition verification

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Solution Overview

Problem

Refrigeration systems face challenges in determining the correct refrigerant composition, especially with the transition from traditional A1 refrigerants to low Global Warming Potential (GWP) A2L refrigerants, which are often mildly flammable, and require accurate methods to ensure safe and efficient operation.

Innovation Solution

A method and system that measure the pressure and temperature (dewpoint and bubble point) of the refrigerant in a refrigeration system, comparing measured values to expected values to determine the correct refrigerant composition, with a controller selecting the appropriate heat exchanger based on ambient temperatures and operating a fan to facilitate accurate readings, and determining the correctness of the refrigerant composition within predefined error thresholds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If refrigerant composition verification is performed continuously, then accuracy of refrigerant identification is improved, but system complexity increases

Engineering Contradiction:
Improverefrigerant composition verification accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system uses existing operational parameters (pressure and temperature readings already taken during normal operation) to calculate dewpoint and bubble point temperatures, thereby self- verifying refrigerant composition without requiring external specialized equipment. This approach achieves accurate refrigerant identification while minimizing additional system complexity by leveraging data already collected during system operation.

Inventive Principle:
Principle #25Self-service

2Measurement precision

If multiple measurements are taken to verify refrigerant composition, then measurement precision is improved, but time consumption increases

Engineering Contradiction:
Improverefrigerant composition accuracyVSAvoidverification time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system performs refrigerant composition verification during the normal operation cycle by utilizing pressure and temperature measurements already taken for operational control. By integrating the verification process with existing operational measurements rather than performing separate dedicated verification steps, the system achieves accurate refrigerant identification without adding significant time consumption to the operational cycle.

Inventive Principle:
Principle #10Preliminary action

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 approach allows for precise identification of correct refrigerant composition, distinguishing between correct and incorrect or contaminated refrigerants, ensuring safe and efficient operation of refrigeration systems by accurately determining the presence of low GWP refrigerants.

Implementation Method 1

measuring a pressure of refrigerant fluid in a refrigerant line of a heat exchanger

Methodology Applied
Scientific EffectPressure measurement:

Implementation Method 2

measuring a value of at least one of a dewpoint temperature and a bubble point temperature of the refrigerant fluid

Methodology Applied
Scientific EffectTemperature measurement:

Implementation Method 3

measuring a pressure of refrigerant fluid in a refrigerant line of a heat exchanger

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 4

a fan is operated, for a predefined time period, to pass air through the heat exchanger

Methodology Applied
Scientific EffectForced convection: Forced Convection

Data Source

PatentEP4028702B1Diagnostic for refrigerant composition verification
Publication Date: 2024.10.30 CARRIER CORP
  • EP4028702B1 patent drawingFigure 1
  • EP4028702B1 patent drawingFigure 2
  • EP4028702B1 patent drawingFigure 3

AI summary

A method for a refrigeration system according to an example of the present disclosure includes measuring a pressure of fluid in a refrigerant line of a heat exchanger of a refrigeration system, and measuring a value of at least one of a dewpoint temperature and a bubble point temperature of the fluid at the measured temperature. The method also includes determining an expected value associated with said at least one of the dewpoint temperature and the bubble point temperature of the fluid at the measured pressure, and determining whether the fluid includes a correct refrigerant composition based on a comparison of the measured and expected values. A refrigeration system operable to determine whether a fluid includes a correct refrigerant composition is also disclosed.