Air Conditioner Refrigerant Filling with Minimum Precharge

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Solution Overview

Problem

Existing air-conditioner refrigerant injection methods are inefficient when the specifications of crossover pipes are unknown, leading to slow refrigerant injection and prolonged installation times due to the need for initial full refrigerant injection.

Innovation Solution

An air-conditioner refrigerant injecting method that calculates and injects the minimum required refrigerant amount based on measurable or estimable pipe lengths and diameters, allowing for automatic injection until the specified amount is reached, eliminating the need for initial full injection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the specified amount of refrigerant is automatically injected from the beginning when pipe specifications are unknown, then the refrigerant injection is precise, but the installation time is prolonged

Engineering Contradiction:
Improverefrigerant injection precisionVSAvoidinstallation time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by first injecting a minimum required amount of refrigerant based on estimated pipe specifications before performing automatic refrigerant injection. This preliminary injection prepares the system in advance, allowing the automatic injection to complete faster since it only needs to add the difference between the minimum and specified amounts, thereby reducing total installation time while maintaining precision

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent segments the refrigerant injection process into two distinct phases: (1) preliminary injection of the minimum required amount based on pipe estimation, and (2) automatic injection of the remaining amount to reach the specified total. This segmentation allows each phase to be optimized independently, improving overall efficiency

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If the specified amount of refrigerant is automatically injected from the beginning, then the refrigerant amount is correct, but the injection speed is slow

Engineering Contradiction:
Improverefrigerant amount accuracyVSAvoidinjection speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent applies partial action by injecting only the minimum required amount of refrigerant in the preliminary phase rather than the full specified amount. This partial injection prepares the system adequately for operation while leaving room for the subsequent automatic injection phase to complete the remaining amount, thereby achieving the correct total amount with improved overall injection speed

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP2562493B1Air conditioner refrigerant filling method
Publication Date: 2018.03.28 MITSUBISHI HEAVY IND THERMAL SYST
  • EP2562493B1 patent drawingFigure 1
  • EP2562493B1 patent drawingFigure 2
  • EP2562493B1 patent drawingFigure 3

AI summary

Provided is an air-conditioner refrigerant injecting method that enables precise and quick injection of an optimum amount of refrigerant . In an air-conditioner (1) refrigerant injecting method of injecting a specified amount of refrigerant into a closed-cycle refrigerant circuit (3) in which an outdoor unit (10) and a plurality of indoor units (11) to (16) are connected via refrigerant pipes (2), the pipe lengths and pipe diameters of the refrigerant pipes (2A) to (2M) connecting the outdoor unit (10) and the plurality of indoor units (11) to (16) installed on the respective floors of a structure (40) are identified insofar as they can be reliably measured or estimated, the minimum required refrigerant amount required by the air conditioner (1) is calculated on the basis of the pipe lengths and pipe diameters, the resulting amount of refrigerant is additionally injected in advance, and then the refrigerant is automatically injected by an automatic refrigerant injection function until a specified injection amount is reached.