Outdoor Unit Baffle Plate Layout for Low-Noise Airflow

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Solution Overview

Problem

In outdoor units of air conditioners, there is a need to reduce ventilation resistance and noise levels.

Innovation Solution

The outdoor unit design includes a casing with a heat exchanger, an axial-flow fan, a bell mouth, and a baffle plate attached to the inner surface of the casing, which inclines towards the bell mouth, guiding air efficiently and reducing resistance and noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If air flows directly from the heat exchanger to the axial-flow fan without guidance, then the structure is simple, but ventilation resistance increases and noise is generated

Engineering Contradiction:
Improvestructural simplicityVSAvoidventilation resistance and noise
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

A baffle plate is introduced as an intermediary component between the heat exchanger and the axial-flow fan. The baffle plate includes a guiding surface that redirects air flow from the heat exchanger toward the bell mouth, preventing direct collision with the fan and reducing turbulence. This mediator structure resolves the contradiction by adding a simple geometric element that significantly reduces ventilation resistance and noise without complex mechanisms.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The baffle plate incorporates a curved guiding surface instead of a flat or angular structure. The curved surface smoothly redirects air flow, reducing turbulence and eddy currents that cause noise and resistance. The spherical/curved geometry optimizes flow patterns while maintaining manufacturing simplicity, effectively resolving the contradiction between structural simplicity and performance.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Object-affected harmful factors

If the baffle plate is positioned close to the heat exchanger, then air flow guidance is improved, but the available space for other components is reduced

Engineering Contradiction:
Improveair flow guidance qualityVSAvoidavailable space in casing
Core Design Contradiction:
Object-affected harmful factorsVSVolume of stationary object

Solution Approach 1:

The baffle plate is positioned locally at the optimal location between the heat exchanger and fan, rather than extending throughout the entire casing. The guiding surface is concentrated only where needed to redirect air flow, leaving the rest of the space available for other components. This localized approach resolves the contradiction by providing effective flow guidance while minimizing space consumption.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The baffle plate utilizes the vertical dimension by extending upward from the base plane, creating a three-dimensional flow guidance structure. This allows effective air redirection without occupying excessive horizontal space, resolving the contradiction between flow guidance quality and available component space through spatial optimization.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 reduces ventilation resistance and enhances heat exchange efficiency, leading to a quieter operation of the outdoor unit.

Implementation Method 1

Air flows into the outdoor unit by rotation of the axial-flow fan, and the air flowing therein passes through the heat exchanger

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 2

heat exchange is performed between refrigerant flowing through a heat exchanger and air passing through the heat exchanger

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 3

air passing through the heat exchanger flows toward the axial-flow fan

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 4

air passing through the heat exchanger and colliding with the second wall portion flows along the baffle plate and is guided to the bell mouth

Methodology Applied
Scientific EffectFlow guidance: Flow Separation

Data Source

PatentEP3410026B1Outdoor machine and air conditioner provided with same
Publication Date: 2023.06.07 MITSUBISHI ELECTRIC CORP
  • EP3410026B1 patent drawingFigure 1~2
  • EP3410026B1 patent drawingFigure 3
  • EP3410026B1 patent drawingFigure 4~5

AI summary

A heat exchanger (23), an axial-flow fan (25), a bell mouth (27), a fan motor (29), and a baffle plate (37) are disposed in a casing (21) of an outdoor unit (11). The casing (21) includes a front panel (33) provided with an air outlet (21b), and a rear panel (35) provided with an air inlet (21a). The bell mouth (27) and the baffle plate (37) are disposed on an inner surface of the front panel (33). The bell mouth (27) has a first opening (27a) opened toward the heat exchanger (23), and a second opening (27b) opened toward the air outlet (21b). The baffle plate (37) is disposed to incline from a predetermined position on the inner surface of the front panel (33) toward where the bell mouth (27) is disposed.