Branch Controller Layout to Block Refrigerant Intrusion

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Solution Overview

Problem

The use of noncontact switches and gas-permeable films in air-conditioning systems to prevent refrigerant leakage into electric components is costly and lacks long-term reliability, requiring frequent maintenance and increasing operational costs.

Innovation Solution

A distribution controller design with a housing that includes a communicating portion below 1/3 of its height, an electric component box, and a control unit positioned to minimize refrigerant intrusion, using a wide band gap semiconductor and a sealed structure to prevent refrigerant exposure to electric components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If noncontact switches and gas-permeable films are used to prevent refrigerant leakage into electric components, then safety is improved, but cost increases significantly and reliability decreases due to film deterioration requiring frequent maintenance

Engineering Contradiction:
ImprovesafetyVSAvoidcost and maintenance
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The housing is divided into a refrigerant-intake region and an electric component accommodation region separated by a partition wall. The communicating portion is positioned at the lower end of the partition wall, creating a segmented structure that isolates electric components from refrigerant while maintaining cost-effectiveness and reliability without requiring expensive noncontact switches or gas-permeable films

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The partition wall with its communicating portion acts as an intermediary structure between the refrigerant-intake region and the electric component accommodation region. It allows controlled interaction (airflow through the communicating portion) while preventing harmful refrigerant intrusion, replacing the need for complex protective measures like noncontact switches and gas-permeable films

Inventive Principle:
Principle #24Intermediary (Mediator)

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 design significantly enhances safety and reduces maintenance costs by minimizing refrigerant intrusion into the electric component box, while maintaining system reliability and efficiency.

Implementation Method 1

The communicating portion is disposed at a level lower than 1/3 of a height of the housing from a bottom surface of the housing

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP2833074B1Branch controller and air-conditioning device provided therewith
Publication Date: 2017.04.19 MITSUBISHI ELECTRIC CORP
  • EP2833074B1 patent drawingFigure 1
  • EP2833074B1 patent drawingFigure 2
  • EP2833074B1 patent drawingFigure 3

AI summary

A housing 10a has a communicating portion 305 that communicates between the housing 10a and an electric component box 30. The communicating portion 305 is disposed at a level lower than 1/3 of the height of the housing 10a from a bottom surface E2 of the housing 10a. A bottom surface E4 of a control unit 50 and a bottom surface E5 of an electric component (relay) 33 are arranged at a level higher than 1/3 of the height of the electric component box 30 from a bottom surface of the electric component box 30.