Finned Coiled Heat Exchanger for Better Gas-to-Duct Contact

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Solution Overview

Problem

Conventional heat exchangers suffer from inefficient heat exchange due to burned gases not fully striking coiled ducts, especially when multiple ducts are intertwined, leading to suboptimal thermal efficiency.

Innovation Solution

A heat exchanger design featuring a coiled duct with radially extending fins along its outer surface, guiding burned gases to strike the duct's surface more effectively, and internal division into parallel channels to accommodate multiple fluids, enhancing heat exchange efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If multiple coiled ducts are used in the heat exchanger, then the heat exchange capacity is increased, but the fluidodynamic limits prevent burned gases from completely striking the ducts, reducing heat exchange efficiency

Engineering Contradiction:
Improveheat exchange capacityVSAvoidheat exchange efficiency
Core Design Contradiction:
Quantity of substanceVSLoss of energy

Solution Approach 1:

The invention introduces a radial dimension to the duct configuration by arranging ducts at different radial distances from the combustion chamber. This multi-dimensional arrangement allows burned gases to effectively strike multiple ducts simultaneously, overcoming the fluidodynamic limits that constrain single-plane multi-duct configurations.

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

Solution Approach 2:

Different ducts are positioned at different radial locations with optimized characteristics for their specific positions. Outer ducts and inner ducts can have different geometries and thermal properties tailored to their local heat exchange requirements, maximizing overall efficiency while maintaining complete gas-duct contact.

Inventive Principle:
Principle #3Local quality

2Area of stationary object

If coiled ducts are intertwined and intercalated to increase heat exchange surface, then the heat exchange area is increased, but evident heat exchange limits occur between outer and inner ducts

Engineering Contradiction:
Improveheat exchange surface areaVSAvoidheat exchange effectiveness
Core Design Contradiction:
Area of stationary objectVSLoss of energy

Solution Approach 1:

The invention transitions from a two-dimensional planar arrangement of intertwined ducts to a three-dimensional radial configuration. Ducts are arranged concentrically at different radial distances from the combustion chamber, allowing burned gases to flow radially outward and contact multiple ducts in sequence, eliminating the heat exchange limits that plague planar intertwined configurations.

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

Solution Approach 2:

The heat exchange system is segmented into multiple independent ducts positioned at different radial levels. Each duct operates semi-independently with optimized surface area and geometry for its specific radial position, allowing the system to achieve high total heat exchange capacity without the interference and fluidodynamic limits that occur when ducts are tightly intertwined.

Inventive Principle:
Principle #1Segmentation

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 significantly improves thermal efficiency by ensuring complete contact between burned gases and the coiled duct, optimizing heat transfer and allowing simultaneous heating of multiple fluids, while being structurally simple, cost-effective, and easy to assemble.

Implementation Method 1

the burned gases 7 produced by the combustion of the combustible mixture 5 are sent forcibly onto the coiled duct 3 thus striking its outer surface in order to heat the fluid to be heated 6

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

the burned gases 7 produced by the combustion of the combustible mixture 5 are sent forcibly onto the coiled duct 3 thus striking its outer surface

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

a plurality of fins 30 is provided which are defined on the outer surface of the coiled duct 3... with consequent increasing of the heat exchange between the hot fluid 7 and the fluid to be heated 6

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 4

a combustion chamber 4 for the combustion of a combustible mixture 5... the burned gases 7 produced by the combustion of the combustible mixture 5

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP2499437B1Heat exchanger with improved thermal efficiency
Publication Date: 2018.05.02 UNIVERSITY OF CALABRIA
  • EP2499437B1 patent drawingFigure 1
  • EP2499437B1 patent drawingFigure 2~3
  • EP2499437B1 patent drawingFigure 4~7

AI summary

A heat exchanger (1) with improved thermal efficiency comprising a container body (2) crossed by a forced flow of hot fluid (7) and at least one coiled duct (3) crossed internally by at least one fluid to be heated (6), the coiled duct (3) being accommodated inside the container body (2) and being struck by the hot fluid (7) in order to heat the fluid to be heated (6), the heat exchanger comprising a plurality of fms (30) which are formed on the outer surface of the coiled duct (3) and which run substantially along the entire longitudinal length of the coiled duct (3) in order to guide the hot fluid (7) along the coiled duct (3) so as to increase the heat exchange between the hot fluid (7) and the fluid to be heated (6).