Multi-Material Heat Exchanger Assembly for Waste Heat Recovery
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Solution Overview
Problem
Existing heat exchanger designs, such as those with spiral tubes, are not adaptable to varying requirements like temperature resistance, thermal conductivity, and corrosion resistance, making them inefficient for different operating conditions, especially in applications like internal combustion engine exhaust systems where temperatures and fluid properties change.
Innovation Solution
A heat exchanger arrangement with at least two components having different material properties, allowing for adaptation to specific requirements by selecting materials based on temperature resistance, thermal conductivity, and corrosion resistance, with sections optimized for high-temperature and low-temperature areas, and incorporating coiled tubing with varying material properties for enhanced heat transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single-material heat exchanger design is used, then the device structure is simple, but it cannot be adapted to different temperature resistance, thermal conductivity, and corrosion resistance requirements
Solution Approach 1:
The heat exchanger is divided into multiple sections along the flow direction, with each section using materials optimized for its specific thermal and corrosion requirements. The first section uses high-temperature resistant material, while subsequent sections use materials with different thermal conductivity and corrosion resistance properties, allowing each local region to have optimal material characteristics for its operating conditions.
Solution Approach 2:
The heat exchanger employs composite construction with inner tubes made of different materials (e.g., stainless steel, aluminum, copper) depending on the section. This composite approach combines the advantages of different materials - high temperature resistance of stainless steel, high thermal conductivity of aluminum or copper - to create a heat exchanger that adapts to varying requirements along its length.
2Reliability
If high thermal conductivity material is used throughout, then heat transfer efficiency is improved, but temperature resistance and corrosion resistance may be compromised
Solution Approach 1:
High thermal conductivity materials like aluminum or copper are used only in sections where moderate temperatures and high heat transfer efficiency are priorities, while high-temperature resistant materials are used in sections exposed to higher temperatures, optimizing both heat transfer and temperature resistance locally.
Solution Approach 2:
The multi-material construction allows combining materials with high thermal conductivity (aluminum, copper) in lower-temperature sections with high-temperature resistant materials (stainless steel) in hotter sections, achieving overall system reliability while maintaining high heat transfer efficiency where applicable.
3Loss of energy
If high-temperature resistant material is used throughout, then temperature resistance is improved, but thermal conductivity and cost increase
Solution Approach 1:
High-temperature resistant materials are applied only in the first section where high temperatures are present, while subsequent sections use materials with better thermal conductivity and lower cost, optimizing thermal performance and reducing overall material cost without compromising temperature resistance where needed.
4Ease of manufacture
If uniform material properties are used, then manufacturing is simplified, but adaptation to varying corrosion conditions is limited
Solution Approach 1:
Different material sections are designed to match specific corrosion conditions in different parts of the heat exchanger, with each section using materials optimized for its local chemical environment, allowing adaptation to varying corrosion requirements while maintaining reasonable manufacturing complexity.
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 solution enables efficient heat transfer by optimizing material properties for different sections of the heat exchanger, ensuring high temperature resistance, thermal conductivity, and corrosion resistance, thereby improving the overall efficiency and reliability of heat recovery systems in varying conditions.
Implementation Method 1
heat can be transferred from a heating fluid generated by the waste heat source to a working fluid flowing through the heat transfer element
Implementation Method 2
at least one heat transfer element is arranged within the secondary flow channel, by means of which heat can be transferred
Data Source
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AI summary
The invention relates to a device for recovering heat from a heating fluid, having a heat exchanger assembly (1) comprising a main flow channel (3) which is surrounded by an auxiliary flow channel (2). At least one heat exchanger element (4), by means of which heat can be transferred from a heating fluid generated by a waste heat source into the working fluid flowing through the heat exchanger element (4) during the operation of the waste heat source, is provided within the auxilary flow channel (2). In addition, the heat exchanger element (4) has at least two components (5, 6), wherein in at least one section (7, 8) of the heat exchanger element (4), the material of a first component (5) of the heat exchanger element (4), through which first component the working fluid can flow, and the material of a second component (6) of the heat exchanger element (4), which second component increases the surface of the heat exchanger element (4), have different material properties.