Helical Heat Exchange Cell Layout to Prevent Gas Bypass
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Solution Overview
Problem
Existing heat exchange cells face inefficiencies in heat transfer due to preferential bypass pathways of combustion gases, leading to reduced thermal power delivery and increased size, while configurations with partition elements compromise on thermal power for improved condensing capacity and axial extension.
Innovation Solution
A heat exchange cell design featuring a separating element mounted externally to the heat exchanger, with a configuration allowing parallel fluid flow between the heat exchanger and collection chambers, and optimized fluid dynamics through strategically positioned passages, enhancing heat exchange efficiency and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a helically-shaped heat exchanger is used to increase heat exchange surface area, then heat exchange efficiency is improved, but axial extension increases
Solution Approach 1:
The patent transitions from a traditional axial helical configuration to a radial arrangement where the heat exchanger coils are positioned perpendicular to the axial direction. This dimensional change allows the heat exchange surface to be distributed radially rather than axially, maintaining high heat exchange efficiency while minimizing axial extension of the device.
Solution Approach 2:
The patent employs curved and radial flow paths within the combustion chamber, directing combustion gases to flow radially across the heat exchanger coils. This curved flow pattern increases the effective heat exchange surface area utilization without requiring additional axial length, as the gases follow a radial trajectory through the compact coil arrangement.
2Productivity
If partition elements are added to improve condensing capacity, then heat exchange capacity is improved, but thermal power delivery is reduced
Solution Approach 1:
The patent segments the combustion chamber into distinct zones: a primary combustion zone where high-temperature thermal power transfer occurs, and a secondary condensation zone where lower-temperature condensation heat exchange takes place. This spatial segmentation allows both high thermal power delivery and condensing capacity to occur simultaneously in different regions without the trade-off present in partitioned axial designs.
Solution Approach 2:
Different regions of the heat exchanger are optimized for different functions: coils positioned in the primary combustion zone are exposed to high-temperature gases for maximum thermal power transfer, while coils in the secondary zone operate at lower temperatures for condensation. This local optimization of heat exchange conditions in different spatial locations enables both high thermal power and condensing capacity.
3Productivity
If combustion gases flow radially through heat exchanger coils, then heat exchange efficiency is improved, but preferential bypass pathways reduce effectiveness
Solution Approach 1:
The patent introduces a centrally positioned baffle or separator element that acts as an intermediary to block preferential bypass pathways. This baffle forces the combustion gases to follow the intended radial flow path through all heat exchanger coils, preventing short-circuiting and ensuring complete utilization of the heat exchange surface area, thereby eliminating energy loss through bypass.
Solution Approach 2:
The radial flow configuration combined with central baffling creates a flow pattern where gases must pass through multiple coil turns in sequence. The flow dynamics naturally create feedback loops where pressure differentials ensure gases traverse the entire heat exchange surface, preventing bypass and maximizing heat extraction efficiency.
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 high maximum thermal power with minimized axial size, improved heat exchange capacity, and optimized fluid dynamics, reducing axial extension and pressure losses while maintaining overall efficiency.
Implementation Method 1
transfer thermal energy between two fluids
Implementation Method 2
heat exchange between a first heat transfer fluid circulating within the heat exchanger, and a second heat transfer fluid flowing in the containment casing externally to the heat exchanger
Implementation Method 3
heat exchange cells of the condensation type configured to use both the heat developed as a result of combustion, and the latent condensation heat contained in the combustion gases
Data Source
Figure 1
Figure 2a~2b
Figure 3
AI summary
A heat exchange cell is described comprising a containment casing (11) comprising a rear wall (11d), a front wall (22) and a peripheral side wall (11c), a helically-shaped heat exchanger (13) comprising at least one tubular duct for the flow of a first heat transfer fluid coiled about a longitudinal axis of the helix according to a plurality of coils and mounted in the containment casing (11); a feeding zone of a second heat transfer fluid, intended for the heat exchange with the first heat transfer fluid, defined in the casing (11) coaxially and internally with respect to the heat exchanger (13); a first chamber (15) for collecting the second heat transfer fluid externally defined with respect to the heat exchanger (13) between a radially outer wall thereof and the peripheral side wall (11c) of the containment casing (11); and a second chamber (16) for collecting the second heat transfer fluid at least partially delimited by at least one separating element (14). The separating element (14) is mounted at an axially external position with respect to the heat exchanger (13) in such a way as to define the second chamber (16) for collecting the second heat transfer fluid between the separating element (14), the peripheral side wall (11c) and the rear wall (11d) or the front wall (22) of the containment casing (11); in this way, the first (15) and the second (16) collection chambers are in fluid communication with each other by means of at least one passage (17a, 17a', 17b-17g; 14e) configured to allow a flow of the second heat transfer fluid substantially in parallel to the peripheral side wall (11c) of the casing (11) and in proximity thereto. The separating element (14) comprises a heat exchange portion in contact with at least one portion of an end coil of the heat exchanger (13) and configured to allow a heat exchange between the coil-shaped portion of the heat exchanger (13) and the second collection chamber (16), while the heat exchange cell (10) further comprises at least one second passage (35) allowing a fluid outlet from the second collection chamber (16) peripherally defined in the second chamber (16) between an axial end (11g) of the peripheral side wall (11c) and the rear wall (11d) or the front wall (22) of the containment casing (11).