Refrigerant Circuit Segmentation for Accurate Air Conditioner Charge Judgment

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Solution Overview

Problem

Existing methods for judging the adequacy of refrigerant quantity in air conditioner circuits require extensive calculations, making them impractical for low-cost devices like microcomputers and leading to long calculation times or impossibility due to high computational demands.

Innovation Solution

The air conditioner divides its refrigerant circuit into portions and sets relational expressions between refrigerant quantity and operation state quantities, allowing for accurate calculation and judgment of refrigerant adequacy using a microcomputer, incorporating key operational parameters like temperature and pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a simulation of refrigeration cycle characteristics is performed to judge refrigerant quantity, then the judgment accuracy is improved, but the calculation load increases enormously

Engineering Contradiction:
Improverefrigerant quantity judgment accuracyVSAvoidcalculation load
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The refrigerant circuit is divided into multiple portions (e.g., high-pressure liquid refrigerant portion, low-pressure gas refrigerant portion, etc.), and the refrigerant quantity is calculated for each portion separately using simplified relational expressions. This segmentation allows the complex simulation to be replaced with multiple simple calculations, reducing the overall calculation load while maintaining judgment accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the calculation parameters from complex simulation variables to simple operational state quantities (temperature, pressure, flow rate) that can be directly measured. By establishing relational expressions between refrigerant quantity and these measurable parameters for each circuit portion, the system achieves accurate judgment without requiring enormous computational resources.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If a simulation of refrigeration cycle characteristics is performed to judge refrigerant quantity, then the judgment accuracy is improved, but the calculation time becomes excessively long

Engineering Contradiction:
Improverefrigerant quantity judgment accuracyVSAvoidcalculation time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

By dividing the refrigerant circuit into multiple portions and calculating refrigerant quantity for each portion using simple relational expressions based on operational state quantities, the patent eliminates the need for time-consuming full-system simulation while maintaining accurate judgment capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent replaces the mechanical simulation process with a mathematical calculation system that uses pre-established relational expressions. Instead of performing complex physical simulations, the system directly calculates refrigerant quantity from measured operational parameters, dramatically reducing calculation time.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If a simulation of refrigeration cycle characteristics is performed to judge refrigerant quantity, then the judgment accuracy is improved, but the calculation becomes impossible for low-cost devices

Engineering Contradiction:
Improverefrigerant quantity judgment accuracyVSAvoiddevice cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent segments the refrigerant circuit into multiple portions and uses simple relational expressions for each segment, which can be processed by low-cost microcomputers. This approach makes refrigerant quantity judgment feasible for cost-sensitive applications while maintaining accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent replaces expensive simulation computation with inexpensive mathematical calculations using pre-stored relational expressions. This allows even low-cost microcomputers to perform accurate refrigerant quantity judgment, making the technology accessible for budget-friendly air conditioner applications.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Data Source

PatentEP1970652B1Air conditioner
Publication Date: 2019.03.27 DAIKIN INDUSTRIES LTD
  • EP1970652B1 patent drawingFigure 1
  • EP1970652B1 patent drawingFigure 2
  • EP1970652B1 patent drawingFigure 3

AI summary

The adequacy of the refrigerant quantity in a refrigerant circuit can be judged with high accuracy while reducing the calculation load. An air conditioner (1) includes a refrigerant circuit (10), refrigerant quantity calculating means, and refrigerant quantity judging means. The refrigerant circuit (10) is configured by the interconnection of a compressor (21), an outdoor heat exchanger (23), and an indoor heat exchanger (42, 52). The refrigerant quantity calculating means uses a relational expression between the refrigerant quantity in each portion of the refrigerant circuit (10) when the refrigerant circuit is divided into a plurality of portions and an operation state quantity of constituent equipment or refrigerant flowing in the refrigerant circuit (10) in order to calculate the refrigerant quantity in each portion from the operation state quantity of constituent equipment or refrigerant flowing in the refrigerant circuit (10). The refrigerant quantity judging means uses the refrigerant quantity in each portion calculated by the refrigerant quantity calculating means in order to judge the adequacy of the refrigerant quantity in the refrigerant circuit (10).