Multi-Passage Heat Exchanger Tubes for Compact Baker's Ovens
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional heat exchangers in baker's ovens are inefficient, leading to a large footprint and high running costs, as they require more fuel to heat cooking air, and increasing the surface area or adding more tubes increases air friction and costs without significantly improving efficiency.
Innovation Solution
A cross-flow tube heat exchanger with elongated tubes featuring longitudinally extending interior walls that divide the tube into compartments, optimizing the inner surface area to enhance heat transfer while minimizing outer surface area, thereby reducing fuel consumption and allowing for a smaller oven footprint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional heat exchanger tubes with circular or rectangular cross-section are used, then the heat exchanger is compact, but the heat transfer efficiency is insufficient and footprint is large
Solution Approach 1:
The interior of the heat exchanger tube is divided into multiple longitudinal passages by interior walls, creating multiple flow paths for the exhaust gases. This segmentation increases the effective heat transfer surface area within the same external dimensions, improving heat transfer efficiency without increasing the overall footprint of the heat exchanger.
Solution Approach 2:
The invention transitions from a single-channel tube design to a multi-passagement design by adding longitudinal interior walls. This dimensional change in the internal structure creates additional heat transfer surfaces along the length of the tube, effectively increasing the heat transfer area without expanding the external footprint.
2Productivity
If the surface area of heat exchanger tubes is increased to improve heat transfer, then heat transfer efficiency improves, but air friction on the cold side increases requiring larger fans
Solution Approach 1:
By dividing the tube interior into multiple passages, the exhaust gas flow is distributed across smaller channels. This maintains better flow control and heat transfer efficiency without creating excessive resistance on the external cooking air side, thus avoiding increased air friction that would require larger fans.
Solution Approach 2:
The interior walls are strategically positioned to create optimal flow patterns within the tube. This local modification of the flow structure enhances heat transfer in specific regions without creating turbulence or resistance that would affect the external air flow and increase friction losses.
3Productivity
If more heat exchanger tubes are added to increase heat flow, then heat transfer efficiency improves, but device complexity and material requirements increase
Solution Approach 1:
Instead of adding more separate tubes, the invention segments the interior of existing tubes into multiple passages. This achieves the effect of having multiple heat transfer channels within each tube, improving heat transfer efficiency without increasing the number of tubes, connections, or overall device complexity.
Solution Approach 2:
The invention combines multiple heat transfer passages within a single tube structure. By merging several flow channels into one integrated tube with interior walls, it achieves the heat transfer capacity of multiple tubes while reducing the overall number of components, connections, and material requirements.
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 optimized heat exchanger design improves efficiency by increasing heat flux and reducing fuel usage, enabling the production of baker's ovens with a smaller footprint and lower running costs without increasing air friction, while maintaining high thermal transfer capabilities.
Implementation Method 1
The heat exchanger pipes are normally in the shape of tubes with circular transverse cross-section or rectangular with rounded short sides and are made of a material with a high coefficient of heat transfer. The exhaust gases pass though the inside (known as the 'hot side') of the heat exchanger heat transfer tubes and the cooking air is forced to flow around the outside of the tubes
Implementation Method 2
The cooking air enters the heating chamber at the bottom of the chamber where the exhaust gas is at its lowest temperature and circulates up past the heat exchanger tubes and burner exhaust tube where the temperature is highest before being transported into the cooking chamber of an oven. This flow of air is driven by a fan.
Data Source
AI summary
In order to improve the transfer of heat from a warm fluid inside a heat exchanger tube (333) including an elongated tube with a wall with an exterior surface and an interior surface, the interior surface is provided with at least one longitudinally extending interior wall (363′, 363″) which extends from one side of the interior surface towards another side of the interior surface.