Refrigerant Amount Determination Using Stored Correction Coefficients

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Solution Overview

Problem

Conventional methods for determining refrigerant amount in refrigerating cycle apparatuses are labor-intensive, inaccurate due to seasonal and installation location variations, and fail to account for uneven refrigerant distribution and supercritical states, leading to inefficiencies and potential refrigerant leakage.

Innovation Solution

A refrigerant amount determination system that calculates refrigerant amounts based on operation state parameters and compares them to stored values, using correction coefficients to adjust for installation conditions, pipe lengths, and refrigerant type, ensuring accurate determination regardless of environmental or installation conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If regression analysis is employed for calculating the refrigerant amount, then the refrigerant amount can be determined, but numerous test parameters must be determined which takes much labor and time

Engineering Contradiction:
Improverefrigerant amount determinationVSAvoidtime for determining test parameters
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent pre-stores the relationship between operation state amounts and refrigerant amounts in a storage device, eliminating the need to perform regression analysis and determine numerous test parameters during actual operation. This preliminary preparation of data relationships allows for rapid refrigerant amount calculation without time-consuming parameter determination.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates a simplified copy of the complex regression analysis by pre-storing the calculated relationships between operation state amounts and refrigerant amounts. Instead of performing the full regression analysis each time, the system uses the pre-computed stored data to quickly determine refrigerant amounts based on current operation states.

Inventive Principle:
Principle #26Copying

2Measurement precision

If the refrigerant amount is calculated using conventional methods, then the calculation can be performed, but the accuracy decreases due to seasonal and installation location variations

Engineering Contradiction:
Improverefrigerant amount calculation accuracyVSAvoidadaptability to seasonal and installation conditions
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent changes the approach from using fixed calculation formulas to using stored operational data that captures variations under different conditions. By storing actual operation state amounts and corresponding refrigerant amounts from various seasons and installation locations, the system adapts to different conditions without requiring formula modifications.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system uses stored historical operation data as feedback to improve accuracy. By comparing current operation state amounts with stored data patterns, the system can determine refrigerant amounts more accurately across different seasonal and installation conditions, as the stored data reflects actual performance variations.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If conventional refrigerant amount determination is used, then the process can be completed, but it fails to account for uneven refrigerant distribution and supercritical states leading to inaccuracies

Engineering Contradiction:
Improverefrigerant amount determination accuracyVSAvoidcomplexity of accounting for distribution and state variations
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent enables the system to self-correct for uneven refrigerant distribution and supercritical states by using stored operational data that inherently captures these conditions. The stored operation state amounts reflect actual system behavior including distribution variations and supercritical states, allowing the system to determine accurate refrigerant amounts without requiring separate correction mechanisms.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system pre-stores operational data that includes information about uneven refrigerant distribution and supercritical states encountered during normal operation. This preliminary capture of diverse operational conditions allows the system to accurately determine refrigerant amounts even when these complex conditions occur, without requiring real-time analysis or correction.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2416096B1Refrigeration cycle device
Publication Date: 2024.06.12 MITSUBISHI ELECTRIC CORP
  • EP2416096B1 patent drawingFigure 1
  • EP2416096B1 patent drawingFigure 2
  • EP2416096B1 patent drawingFigure 3

AI summary

A refrigerating cycle apparatus is obtained that can determine excess/shortage of a refrigerant amount in a refrigerating circuit at high precision even if a factor such as a heat exchanger whose refrigerant amount is difficult to calculate exists. The refrigerating cycle apparatus according to the present invention includes one heat source unit 301 or more, one utilization unit 302 or more, a refrigerating circuit constituted by the heat source unit 301 and utilization unit 302, a storage part 104 which stores an appropriate refrigerant amount of a refrigerant to be charged in the refrigerating circuit and a correction coefficient which corrects a liquid refrigerant amount such that calculation of the refrigerant amount of each constituent element of the refrigerating circuit is equal to the appropriate refrigerant amount, a measurement part 101 which detects an operation state amount in each constituent element of the refrigerating circuit, a calculation part 102 which calculates the refrigerant amount of each constituent element of the refrigerating circuit based on the operation state amount by using the correction coefficient, a comparison part 105 which compares the appropriate refrigerant amount with a calculative refrigerant amount calculated by the calculation part 102, and a determination part 106 which determines excess/shortage of the refrigerant amount charged in the refrigerating circuit based on a comparison result of the comparison part 105,