Concentric Tube Bundle Heat Exchanger for Sequential Heating
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Solution Overview
Problem
Existing condensation heat exchangers suffer from poor energy efficiency, excessive heating of water in some bundles leading to boiling, and parasitic turbulence due to imperfect sealing, resulting in higher pollutant emissions and reduced performance.
Innovation Solution
A modular condensation heat exchanger design featuring concentric tube bundles with a single collector and internal partitions that direct the heat-transfer fluid to circulate successively through each bundle, minimizing head losses and optimizing temperature gradients for efficient heating and cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If water circulates simultaneously through interior and exterior bundles, then both bundles are heated, but water in interior bundle is overheated causing boiling and thermal loading
Solution Approach 1:
The patent segments the tube bundles into interior and exterior groups with separate water circulation paths. Water enters the exterior bundle first, then flows to the interior bundle through a collector, preventing simultaneous heating and overtemperature in the interior bundle.
Solution Approach 2:
The patent implements preliminary heating in the exterior bundle before water enters the interior bundle. This staged approach ensures water is gradually heated, preventing thermal shock and overheating in subsequent bundles.
2Temperature
If water is heated to high temperature in interior bundle, then desired outlet temperature is achieved, but hot gases cool insufficiently and fail to condense
Solution Approach 1:
The patent divides the heating process into two stages: exterior bundle for initial heating and interior bundle for final temperature adjustment. This ensures hot gases progressively cool through each bundle, maximizing condensation and heat recovery.
Solution Approach 2:
The patent inverts the conventional arrangement by placing the exterior bundle (further from burner) to receive cold water first, while the interior bundle (closer to burner) receives preheated water. This counterintuitive arrangement optimizes both water heating and gas cooling efficiency.
3Ease of repair
If cover and barrier are removed for cleaning, then tube access is improved, but parasitic turbulence and flow disparity occur
Solution Approach 1:
The patent designs the collector with removable sections that provide vertical access to horizontal tube bundles. This dimensional approach allows cleaning without disassembling the entire exchanger, maintaining flow path integrity when properly reassembled.
4Temperature
If interior bundle is heated more than necessary, then outlet temperature requirement is met, but device bulk and weight increase
Solution Approach 1:
The patent applies partial heating in the exterior bundle followed by controlled heating in the interior bundle. This staged approach achieves the required outlet temperature with optimized heat transfer, reducing the overall size and weight of the exchanger compared to uniform heating of all bundles.
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 maximum thermal efficiency, reduces head losses, and prevents overheating, leading to lower emissions and extended power range capabilities with a reduced power/bulk/weight ratio, while allowing for easier assembly and longevity.
Implementation Method 1
a heat exchange device wherein a heat-transfer fluid to be heated, such as water, is designed to circulate
Implementation Method 2
the hot gases produced allow the tubes, and consequently the water which circulates inside them, to be heated
Implementation Method 3
They would leave the device at a relatively elevated temperature which can be estimated on the order of 80° C. These cooled gases would therefore be at a temperature higher than the dew point (equal to 55° C.) and would not condense
Data Source
AI summary
The invention relates to a condensation heat exchanger which comprises: —at least two concentric bundles (5, 5′) of tubes made from a material that is a good thermal conductor, inside which tubes a heat-transfer fluid is intended to circulate, each bundle of tubes (5, 5′) comprising a series of tubes (50, 50′) in the form of an arc of a circle, the tubes of each bundle (5, 5′) being arranged in parallel planes with a gap (53, 53′) between two adjacent tubes (50, 50′), —a single collector (6) made of a material that is a good conductor of heat and to which the two ends (51, 51′, 52, 52′) of each tube (50, 50′) of the various bundles (5, 5′) are connected, this collector (6) being equipped with inlet (61) and outlet (62) couplings. This exchanger is notable in that the collector (6) comprises several partitions delimiting various channels, which allow the fluid that is to be warmed up to be made to circulate in the various successive bundles from the outermost bundle to the innermost bundle.