Corrugated Fin Heat Exchanger With Drain Holes and Inclined Louvers

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Solution Overview

Problem

The accumulation of condensed water on corrugated fins in heat exchangers reduces air flow resistance and can freeze during low-temperature operations, leading to decreased heat exchange efficiency.

Innovation Solution

A heat exchanger design featuring zigzag-shaped corrugated fins with drain holes and inclined louvers, where first louvers are upstream and second louvers are downstream of the drain holes, enhancing water drainage and reducing residual water, thus preventing freezing and improving efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If louvers are oriented horizontally to the corrugated fins, then air can flow through the louvers, but condensed water accumulates on the louvers increasing resistance and may freeze during low-temperature operation

Engineering Contradiction:
Improveair flow through louversVSAvoidcondensed water accumulation and freezing
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent changes the orientation of louver slats from horizontal to inclined (oblique) orientation. This dimensional change in angle allows water to drain off the louvers while still permitting air flow, resolving the contradiction between air flow ease and water accumulation prevention

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

Solution Approach 2:

The patent provides drain holes at the lower ends of the corrugated fins before water accumulation becomes problematic. This preliminary drainage path prevents water from accumulating on the louvers in the first place, addressing the issue before it affects heat exchange efficiency

Inventive Principle:
Principle #10Preliminary action

2Device complexity

If condensed water accumulates on the louvers, then the structure remains simple, but air flow resistance increases and heat exchange efficiency is reduced

Engineering Contradiction:
Improvelouver structureVSAvoidheat exchange efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The drain holes are pre-positioned at the lower ends of the corrugated fins to provide immediate water drainage capability. This preliminary action prevents water accumulation that would otherwise increase air flow resistance and reduce heat exchange efficiency, maintaining high productivity without adding complex active drainage systems

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

By inclining the louver slats at an angle rather than keeping them horizontal, the patent creates a gravitational drainage path for condensation water. This angular modification allows water to naturally drain off the louvers without requiring additional drainage infrastructure, maintaining structural simplicity while preventing efficiency loss

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

The design effectively reduces water accumulation and freezing on the fins, enhancing heat exchange efficiency by improving water drainage and maintaining airflow, even during low-temperature operations.

Implementation Method 1

a drain hole provided adjacent to central regions of the flat surfaces of the plurality of flat heat transfer tubes in the direction in which the air flows

Methodology Applied
Scientific EffectGravity: Gravitation

Implementation Method 2

a plurality of first louvers located upstream of the drain hole in the direction in which the air flows, the plurality of first louvers each including a slit and a slat that is inclined in the vertical direction and that causes the air to flow through the slit

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentEP3587988B1Heat exchanger and air conditioner
Publication Date: 2020.10.14 MITSUBISHI ELECTRIC CORP
  • EP3587988B1 patent drawingFigure 1
  • EP3587988B1 patent drawingFigure 2
  • EP3587988B1 patent drawingFigure 3

AI summary

A heat exchanger includes flat cross-sectional shaped heat transfer tubes arranged with gaps between flat surfaces of the flat heat transfer tubes facing each other, and each having a flow passage extending through the flat heat transfer tube in a vertical direction, and corrugated fins each bent in a zigzag shape in the vertical direction and disposed between the flat surfaces facing each other. The corrugated fins each include an end portion located at an upstream end in a direction in which air flows, and protruding from end portions of the flat surfaces, a drain hole provided adjacent to central regions of the flat surfaces of the flat heat transfer tubes in the direction in which the air flows, first louvers located upstream of the drain hole, and each including a slit and a slat that is inclined in the vertical direction and that causes the air to flow through the slit, and second louvers located downstream of the drain hole, and each including a slit and a slat that is inclined in the vertical direction and that causes the air to flow through the slit.