Refrigerant Charge Loss Detection Using Mode-Specific Models

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Refrigerant charge loss in vapor compression systems leads to reduced cooling capacity and potential compressor failure, with existing methods failing to accurately detect the amount of charge loss in non-critically charged systems with wide set point and ambient ranges.

Innovation Solution

A system and method using a controller to determine the mode of operation of a compressor and apply specific models to operating condition parameters to detect refrigerant charge loss, including percentage of loss and estimated modulation percentage, with sensors measuring various temperatures and parameters to generate alerts when charge loss exceeds thresholds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If existing loss of charge detection methods are used, then the system can detect refrigerant charge loss, but the detection accuracy is insufficient for non-critically charged systems with wide set point and ambient ranges

Engineering Contradiction:
Improvedetection accuracyVSAvoidapplicability to wide operating ranges
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The detection system segments the operating range into multiple modes (full capacity and partial capacity operations) and applies different loss of charge detection models for each mode. This segmentation allows accurate detection across wide set point and ambient ranges by selecting the appropriate model based on current operating conditions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically selects and switches between different detection models based on the compressor's operating mode. The controller determines the current mode and applies the corresponding model, enabling the system to adapt to varying operating conditions while maintaining high detection accuracy.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If multiple detection models are applied for different operating modes, then the detection accuracy improves, but the system complexity increases

Engineering Contradiction:
Improveloss of charge detection accuracyVSAvoidcontroller complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The controller dynamically determines the compressor operating mode and selectively applies appropriate detection models. This dynamic approach maintains high detection accuracy while managing complexity by only activating the necessary model for current conditions rather than running all models simultaneously.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system performs preliminary determination of the operating mode before applying detection models. This preliminary classification simplifies the overall process by organizing the detection logic into clear sequential steps, reducing controller complexity while maintaining accuracy.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3574271B1Low charge detection system and method for cooling systems
Publication Date: 2023.10.04 COPELAND LP
  • EP3574271B1 patent drawingFigure 1
  • EP3574271B1 patent drawingFigure 2
  • EP3574271B1 patent drawingFigure 3

AI summary

Systems and methods that detect a loss of charge associated with a climate controlled environment are described in the present disclosure. In various embodiments, a controller receives operating condition parameters associated with a climate-controlled environment. The controller determines whether a compressor is operating in a first mode of operation or a second mode of operation. The controller applies a first model to the operating condition parameters when the compressor is operating in the first mode of operation to represent a loss of charge associated with the climate-controlled environment and applies a second model to the operating condition parameters when the compressor is operating in the second mode of operation to represent the loss of charge associated with the climate-controlled environment.