Outdoor Unit Heat Exchanger Layout for Uniform Refrigerant Flow

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Solution Overview

Problem

The existing air-conditioning apparatuses face challenges in achieving uniform refrigerant distribution, leading to degraded heat exchange performance and reduced energy efficiency, particularly due to complex structures that increase costs when attempting to improve refrigerant distribution within the outdoor unit's header.

Innovation Solution

The outdoor unit of the air-conditioning apparatus employs a dual heat exchanger configuration, where high-performance flat pipes are positioned closer to the fan for efficient heat exchange and low-cost circular pipes are positioned farther away, utilizing a distributor with capillary tubes to ensure uniform refrigerant distribution, thereby optimizing energy efficiency while minimizing cost increments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a turbulence promoting member is provided in the header to agitate the refrigerant, then the refrigerant distribution uniformity is improved, but the device complexity and manufacturing cost increase

Engineering Contradiction:
Improverefrigerant distribution uniformityVSAvoidheader structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by providing turbulence promoting members only at specific locations within the header where refrigerant distribution needs improvement, rather than throughout the entire header. This localized approach enhances refrigerant mixing where needed while minimizing overall device complexity and manufacturing cost.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If the header structure is adjusted to improve refrigerant distribution, then the refrigerant distribution performance is improved, but the device complexity increases

Engineering Contradiction:
Improverefrigerant distribution performanceVSAvoidheader structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent modifies the header structure locally by adding turbulence promoting members at specific positions rather than redesigning the entire header. This allows improvement of refrigerant distribution performance while keeping the overall header structure simple and easy to manufacture.

Inventive Principle:
Principle #3Local quality

3Use of energy by moving object

If high-performance flat pipes are used for heat exchange, then the heat exchange performance is improved, but the manufacturing cost increases

Engineering Contradiction:
Improveheat exchange performanceVSAvoidmanufacturing cost
Core Design Contradiction:
Use of energy by moving objectVSEase of manufacture

Solution Approach 1:

The patent uses high-performance flat pipes selectively in regions where heat exchange performance is most critical (areas with higher air flow rates), while using conventional circular pipes in other regions. This localized application optimizes heat exchange performance where needed while controlling overall manufacturing cost.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs asymmetric pipe configuration by combining flat pipes and circular pipes in different locations within the heat exchanger. This asymmetric design allows optimization of heat exchange performance in high air flow regions while maintaining cost-effectiveness in other areas.

Inventive Principle:
Principle #4Asymmetry

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 configuration enhances heat exchange performance and energy efficiency by directing higher refrigerant flow rates to areas with higher air flow, reducing the complexity and cost of the refrigerant distribution system while maintaining effective refrigerant distribution characteristics.

Implementation Method 1

heat exchange performance

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 2

air flow rates

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

distributor with capillary tubes

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 4

refrigerant distribution

Methodology Applied
Scientific EffectPressure drop: Pressure Drop

Data Source

PatentEP3370000B1Outdoor unit for air conditioner
Publication Date: 2022.07.20 MITSUBISHI ELECTRIC CORP
  • EP3370000B1 patent drawingFigure 1
  • EP3370000B1 patent drawingFigure 2
  • EP3370000B1 patent drawingFigure 3~5

AI summary

Provided is an outdoor unit of an air-conditioning apparatus including a casing having an air inlet and an air outlet, and forming an outer shell, a fan provided inside the casing, and configured to suck outside air from the air inlet and exhaust the outside air from the air outlet, and a heat exchanger provided inside the casing, and configured to exchange heat between the outside air sucked by the fan and refrigerant, the heat exchanger including a first heat exchanger main body including a plurality of fins arranged in parallel at an interval and a plurality of flat pipes passing through the plurality of fins in a direction of parallel arrangement of the plurality of fins, the refrigerant flowing inside the plurality of flat pipes, and a second heat exchanger main body including a plurality of fins arranged in parallel at an interval and a plurality of circular pipes passing through the plurality of fins in a direction of parallel arrangement of the plurality of fins, the refrigerant flowing inside the plurality of circular pipes, in which the first heat exchanger main body is arranged closer to the fan than is the second heat exchanger main body.