Biomass Heat Generator Recirculation Duct for Cleaner Heat Exchange

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Solution Overview

Problem

Existing heat generators, particularly those powered by biomass, do not optimize heat exchange between air to be heated and combustion fumes, leading to inefficient heat utilization and high nitrogen emissions with increased pollutant production.

Innovation Solution

A heat generator design featuring a recirculation duct that directs combustion fumes back into the combustion chamber and a separate circuit for comburent air, enhancing heat exchange between these components and improving combustion efficiency while reducing nitrogen emissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If existing heat exchange circuits are used in heat generators, then the device structure is relatively simple, but heat exchange efficiency between air to be heated and combustion fumes is insufficient

Engineering Contradiction:
Improveheat exchange efficiencyVSAvoidheat exchange circuit structure
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The heat exchange circuit is divided into multiple independent sections: a first section where combustion fumes flow, a second section where air to be heated flows, and a third section for recirculation. This segmentation allows each section to be optimized for its specific function while maintaining overall system efficiency, directly addressing the heat exchange inefficiency without requiring complete redesign of the entire system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The design pre-positions the recirculation duct to capture combustion fumes at an optimal location before they fully dissipate, and pre-arranges the heat exchange surfaces to maximize contact time between hot fumes and air to be heated. This preliminary arrangement of components ensures efficient heat transfer occurs naturally through the designed flow paths without requiring additional active control mechanisms.

Inventive Principle:
Principle #10Preliminary action

2Object-generated harmful factors

If combustion fumes are directly discharged without recirculation, then the device complexity is low, but nitrogen emissions are high and combustion completion is insufficient

Engineering Contradiction:
Improvenitrogen emissions and pollutantsVSAvoidrecirculation duct structure
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The recirculation duct creates a feedback loop where a portion of the combustion fumes is redirected back into the combustion chamber. This feedback mechanism allows unburned components and excess oxygen to undergo secondary combustion, completing the combustion process and significantly reducing nitrogen emissions and other pollutants while the recirculation structure remains relatively simple.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

Instead of directly discarding combustion fumes to the environment, the system recovers useful energy from them through the heat exchange circuits and recirculates a portion back for further combustion. This recovery approach extracts remaining thermal energy and promotes complete combustion, reducing harmful emissions while adding only minimal structural complexity through the recirculation pathway.

Inventive Principle:
Principle #34Discarding and recovering

3Use of energy by moving object

If heat exchange between air to be heated and combustion fumes is not optimized, then the device structure is simple, but heat utilization efficiency is low

Engineering Contradiction:
Improveheat utilization efficiencyVSAvoidheat exchange circuit configuration
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The design merges the heat exchange function with the existing combustion chamber structure by integrating heat exchange surfaces within the combustion chamber boundaries. The first and second heat exchange sections are positioned to utilize the natural thermal field of combustion fumes, combining heat extraction with the combustion process itself rather than requiring separate, complex heat exchange systems.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The heat exchange circuits are arranged in spatial dimensions that maximize thermal contact between combustion fumes and air to be heated. The first section utilizes vertical or radial flow paths while the second section employs horizontal or axial arrangements, creating multi-dimensional heat exchange that dramatically improves heat utilization efficiency without significantly increasing structural complexity.

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 achieves effective heat exchange, increases CO2 content, reduces pollutants like particulate matter, and enhances combustion efficiency by optimizing the use of biomass heat generation, thereby improving overall performance.

Implementation Method 1

a recirculation duct (7) which directs combustion fumes (CF) back into the combustion chamber (CC)

Methodology Applied
Scientific EffectThermal energy transfer: Convection

Implementation Method 2

directs combustion fumes (CF) back into the combustion chamber (CC)

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 3

effective heat exchange, in particular between the air to be heated and the combustion fumes

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 4

heat exchange relationship with a respective section of the third circuit (6)

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 5

combustion chamber (CC), in which fuel is burnt

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP4067740B1Heat generator with efficient thermal exchange
Publication Date: 2025.12.17 GRUPPO PIAZZETTA
  • EP4067740B1 patent drawingFigure 1~2
  • EP4067740B1 patent drawingFigure 3~4
  • EP4067740B1 patent drawingFigure 5~6

AI summary

The present invention relates to a heat generator for heating environments comprising a main frame (2) delimiting a combustion chamber (CC), the generator further including a door for opening/closing (3) an opening for accessing to the combustion chamber (CC).