Heating device

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Solution Overview

Problem

Existing heaters face inefficiencies in heat transfer from exhaust gas to heating circuit water due to uniform wall thickness of heat transfer ribs, which does not account for the temperature gradient along the heating gas flue.

Innovation Solution

The wall thickness of heat transfer ribs is varied, with thicker walls at the inlet area to withstand high temperatures and thinner walls at the outlet area to enhance heat transfer, while the heating gas flue wall thickness is made smaller than the smallest rib thickness to optimize heat transfer as exhaust gas cools down.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If uniform wall thickness heat transfer fins are used throughout the flue gas passage, then manufacturing is simple, but heat transfer efficiency is reduced due to inability to adapt to temperature gradient

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidheat transfer efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The heat transfer fins are designed with varying wall thickness along their length, with thicker sections at the inlet area (higher temperature) and thinner sections at the outlet area (lower temperature). This local variation in geometry optimizes heat transfer efficiency at different positions while maintaining structural integrity, directly resolving the contradiction between manufacturing simplicity and heat transfer performance.

Inventive Principle:
Principle #3Local quality

2Strength

If thicker wall thickness is used at inlet area to withstand high temperature, then structural integrity is improved, but heat transfer efficiency at outlet area is reduced

Engineering Contradiction:
Improvestructural integrity at inletVSAvoidheat transfer efficiency at outlet
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The heat transfer fins incorporate position-dependent wall thickness, providing greater thickness at the inlet area where high temperatures require enhanced structural strength, while transitioning to thinner sections at the outlet area where heat transfer efficiency becomes the primary concern. This local differentiation simultaneously satisfies both strength and heat transfer requirements at different locations.

Inventive Principle:
Principle #3Local quality

3Productivity

If thinner wall thickness is used at outlet area to enhance heat transfer, then heat transfer efficiency is improved, but structural integrity at inlet area is compromised

Engineering Contradiction:
Improveheat transfer efficiency at outletVSAvoidstructural integrity at inlet
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The variable wall thickness design ensures that each section of the heat transfer fin has the appropriate thickness for its specific location: thicker at the inlet to withstand high temperatures and mechanical stresses, and thinner at the outlet to maximize heat transfer efficiency. This spatially differentiated design prevents the compromise of structural integrity while achieving enhanced heat transfer where needed.

Inventive Principle:
Principle #3Local quality

4Temperature

If different materials are used at inlet and outlet areas to handle temperature differences, then temperature resistance is improved, but manufacturing complexity increases due to different thermal expansion

Engineering Contradiction:
Improvetemperature resistanceVSAvoidmanufacturing complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

Instead of changing materials along the flue gas passage, the invention maintains a uniform material composition throughout while varying the geometric parameter (wall thickness) of the heat transfer fins. This approach achieves the necessary adaptation to temperature gradients without introducing the manufacturing complexities and thermal expansion incompatibilities that would arise from using different materials at different locations.

Inventive Principle:
Principle #35Parameter changes

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 improves heat transfer efficiency by adapting to temperature changes and ensuring structural integrity, allowing for effective heat exchange and efficient operation as a condensing device.

Implementation Method 1

heat transfer fins, spaced apart from one another and having a wall thickness, are arranged in the flue gas passage for heat transfer from the hot exhaust gas to the flue gas passage

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

heat transfer from the hot exhaust gas to the flue gas passage 2

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3096093B1Heating device
Publication Date: 2019.08.07 VIESSMANN GRP GMBH & CO KG
  • EP3096093B1 patent drawingFigure 1~3
  • EP3096093B1 patent drawingFigure 4~6

AI summary

The invention relates to a heating device, comprising a combustion chamber (1) and a heating gas flue (2) designed to guide hot exhaust gas generated in the combustion chamber (1), said flue having an inlet area (2.1) and an outlet area (2.2) and with which Combustion chamber (1) is designed to be connected via the inlet area (2.1) and heat transfer ribs (3) which are spaced apart from one another and have a wall thickness are arranged in the heating gas flue (2) for heat transfer from the hot exhaust gas to the heating gas flue (2). According to the invention, the wall thickness of the heat transfer ribs (3) and/or the distances between the heat transfer ribs (3) on the inlet area (2.1) side are optionally greater than on the outlet area (2.2) side.