Heat Transfer Device with Asymmetrical Flue Channels

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Solution Overview

Problem

Existing heat transfer devices face challenges in achieving uniform heat transfer from flue gas to heat absorbers, leading to potential stress and reduced service life, while also aiming for high efficiency.

Innovation Solution

The heat transfer device employs asymmetrical, inclined draft channels with varying cross-sectional areas to shift flow distribution orthogonally towards the heat receiver, utilizing an inclined boundary and tapered shape to enhance heat transfer uniformity, and includes a variable cross-sectional area mechanism and cleaning device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the surface area of the flue duct is maximized relative to its volume to achieve large heat transfer area, then heat transfer efficiency is improved, but heat transfer uniformity deteriorates causing thermal stresses

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidheat transfer uniformity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies asymmetry by providing a flue duct with an asymmetric cross-sectional shape that has a distinguished side facing the heat exchanger. This asymmetric configuration causes the hot gas flow to be deflected towards the distinguished side, concentrating heat transfer in a controlled manner on the heat exchanger surface, thereby achieving both high efficiency and uniform heat distribution without thermal stresses

Inventive Principle:
Principle #4Asymmetry

2Reliability

If the flue gas flow is concentrated towards one side to improve heat transfer uniformity, then thermal stresses are reduced, but heat transfer efficiency may deteriorate

Engineering Contradiction:
Improveheat transfer uniformityVSAvoidheat transfer efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies local quality by creating a distinguished side on the flue duct with asymmetric geometry that directs heat transfer preferentially towards the heat exchanger. This localized flow concentration ensures uniform heat distribution on the heat exchanger surface while maintaining high overall heat transfer efficiency through optimized flow guidance

Inventive Principle:
Principle #3Local quality

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 achieves a more uniform heat transfer over the entire surface of the heat absorber with high efficiency, exceeding 85% and allowing for easy cleaning, thereby extending the device's service life and optimizing heat utilization.

Implementation Method 1

a heat absorber (8) that absorbs heat emitted by the flowing gas

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Implementation Method 2

the flue gas is typically cooled to temperatures below 200°C

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

The predominant heat transfer towards one distinguished side is understood to mean a heat flow that is clearly asymmetrically shifted towards this one side with respect to the outer boundary of the flue channel

Methodology Applied
Scientific EffectGravity-driven convection: Free Convection

Data Source

PatentEP2784429B1Heat transfer device and oven equipped with the same
Publication Date: 2019.05.08 RAINER JOHANN
  • EP2784429B1 patent drawingFigure 1
  • EP2784429B1 patent drawingFigure 2
  • EP2784429B1 patent drawingFigure 3

AI summary

Heat transfer device, in particular for downstream connection to a furnace, with a gas inlet (71, 3u) for a gas containing heat, at least one draft channel (3, 6L, 6R) through which the gas flows, a heat absorber (8) which is absorbs the heat given off by the flowing gas, and a gas outlet (3o, 90) for the gas cooled in this way, with the heat receiver (8) being arranged on one side of the at least one flue (3) and the heat given off due to a shape and/or position property of the at least one draft duct (3) predominantly to the side of the heat receiver (8) and a furnace equipped with such a heat transfer device.