Serpentine Bent-Fin Coil Condensing Heat Exchanger for Flue Recovery
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Solution Overview
Problem
Conventional heat exchangers suffer from dead zones and insufficient heat exchange due to poor structure design, limited heat transfer surface, and inefficiencies in flue gas flow, which hinder energy recovery and increase boiler size, while also being costly to manufacture in various sizes.
Innovation Solution
A forced convection helical and serpentine bent fin-tube coils condensing heat exchanger with a counter-flow design, integrated air pre-heater, and strategically placed flue baffles to enhance heat transfer and reduce flue temperature, utilizing helical and serpentine bent fin-tube coils with bent fins to increase surface area and improve flue gas distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional heat exchanger structure is used, then manufacturing is simpler, but dead zones and insufficient heat exchange occur due to poor structure design
Solution Approach 1:
The patent employs helical and serpentine bent fin-tube coils instead of straight tubes. The curved geometry of the coils creates continuous fluid flow paths that eliminate dead zones and improve heat exchange efficiency while maintaining manufacturability through standardized coil formation processes.
Solution Approach 2:
The heat exchanger is divided into multiple coil sections (helical and serpentine patterns) that can be manufactured separately and assembled. This segmentation allows for optimized heat exchange surfaces in each section while keeping individual manufacturing steps manageable and scalable.
2Productivity
If heat transfer surface area is increased, then heat exchange efficiency improves, but device size and manufacturing cost increase
Solution Approach 1:
The patent adds fins to the tubes, extending the heat transfer surface area from one-dimensional tube surfaces to two-dimensional fin surfaces. This dramatically increases the effective heat exchange area without proportionally increasing the device volume, as the fins utilize the existing tube structure as a scaffold.
Solution Approach 2:
The fin structure is nested onto the tube surface, with multiple fins arranged along the tube length. This nested configuration maximizes heat transfer area within the constrained space of the tube diameter, avoiding the need for larger external dimensions.
3Loss of energy
If flue gas flow is improved, then energy recovery increases, but heat exchanger structure becomes more complex
Solution Approach 1:
The helical and serpentine coil configurations create continuous, curved flow paths for flue gas that prevent stagnant zones and promote uniform heat exchange throughout the heat exchanger volume. The curved geometry naturally guides flow without requiring additional flow control components.
Solution Approach 2:
The coil design ensures continuous contact between flue gas and heat exchange surfaces throughout the entire flow path, eliminating dead zones where heat exchange would be interrupted. The serpentine and helical patterns maintain constant fluid motion and thermal interaction from inlet to outlet.
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 significantly enhances heat exchange efficiency, reduces boiler size, and increases energy recovery to 96%–98%, while simplifying manufacturing and reducing material costs by eliminating dead zones and improving flue gas flow distribution.
Implementation Method 1
A forced convection helical and serpentine bent fin-tube coils condensing heat exchanger
Implementation Method 2
enhances heat transfer and reduce flue temperature
Implementation Method 3
the efficiency is 10% higher than the conventional boiler. Abundant water vapor in the flue is condensed and releases the latent heat of vaporization because the flue temperature can be decreased to below the dew point
Implementation Method 4
Abundant water vapor in the flue is condensed and releases the latent heat of vaporization
Implementation Method 5
The water absorbs the sensible heat from the combustion flue gas after absorbing the waste heat of the high temperature flue in the condensing heat exchanger
Data Source
AI summary
A heat exchanger for supplying heat includes a housing, a bundle of helical fin-coil tubes, and a flue channel. The housing includes a burner, a water inlet, a water outlet and a flue gas outlet. The burner is disposed on a top portion of the housing and connected to an air/gas mixture unit. The bundle of helical fin-tube coils is disposed tightly, circularly, and coaxially around the burner. The flue channel is disposed below the burner and is formed by a plurality of serpentine bent fin-tube coils. A flow of flue gas vents from the flue channel to the flue gas outlet. The water inlet is connected to the plurality of serpentine bent fin-tube coils which forms the flue channel below the burner. The plurality of serpentine bent fin-tube coils below the burner are connected to the bundle of helical fin-tube coils. The bundle of helical fin-tube coils are connected to the water outlet.