Offset Tube Heat Exchanger for Engine-Stop Thermal Management
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Solution Overview
Problem
Conventional heat exchangers in motor vehicles, such as air conditioning evaporators and heating radiators, face issues where cooling or heating is disrupted when the engine stops, causing discomfort due to the reliance on engine-driven compressors and pumps, and existing assembly methods are complex with multiple components and challenging tube insertion.
Innovation Solution
A heat exchanger design where first and second tubes form modules with offset ends, allowing for efficient heat exchange and easy assembly by alternating tube insertion into collection boxes with constant pitch holes, using a core of tubes with corrugated spacers for enhanced surface area and a distribution plate structure for fluid management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the compressor is driven by the engine, then the air conditioning system operates reliably during engine operation, but the cooling function stops when the engine stops
Solution Approach 1:
The invention stores thermal energy (cold or heat) in advance during engine operation in the accumulation fluid within the tubes, so that this stored energy can be released and maintain the air conditioning function after the engine stops. The accumulation fluid acts as a thermal battery that is charged during operation and discharged when needed.
2Power
If multiple tubes and collection boxes are used for heat exchange, then heat exchange efficiency is improved, but assembly complexity increases
Solution Approach 1:
The heat exchanger is divided into multiple modular units, each comprising tubes connected to collection boxes. These modules can be assembled in series or parallel configurations. The segmentation allows for standardized manufacturing and simplified assembly procedures while maintaining high heat exchange efficiency through increased surface area.
Solution Approach 2:
The collection boxes serve multiple functions: they collect refrigerant from multiple tubes, distribute refrigerant to different sections, and provide structural support for mounting the heat exchanger. This multi-functionality reduces the need for additional components and simplifies the overall assembly.
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
Ensures continuous air conditioning or heating by allowing accumulation and restoration of heat or cold when the engine is stopped, simplifies assembly with fewer components, and maintains high resistance to refrigerant pressures, providing effective and efficient thermal management.
Implementation Method 1
the first fluid, which is the refrigerant or heat transfer fluid, can exchange heat with a second fluid, which is an accumulation fluid
Implementation Method 2
the presence of a second fluid, which is an accumulation fluid, enables these disadvantages to be avoided. Indeed, this second fluid enables accumulation either of cold (by consequently releasing heat), or of heat
Implementation Method 3
In the evaporator, the refrigerant changes from a liquid phase or a liquid/vapor phase to a vapor phase by receiving heat from the air flow, which is thus cooled
Implementation Method 4
the refrigerant changes from a liquid phase or a liquid/vapor phase to a vapor phase by receiving heat from the air flow
Implementation Method 5
a core of tubes inserted between the two collection boxes and comprising first tubes communicating with the first chambers of the two collection boxes and second tubes communicating with the second chambers of the two collection boxes
Data Source
AI summary
A heat exchanger (10) includes at least one header box (12, 14) delimiting a first chamber (42) for a first fluid (F1) and a second chamber (44) for a second fluid (F2), as well as a beam of tubes (16) ending into the header box (12, 14) and comprising at least one first tube (18) communicating with the first chamber (42) of the collecting box (12, 14) and at least one second tube (20) communicating with the second chamber (44) of the collecting box, the first tube (18) being coupled with the second tube (20) to constitute a module (22) allowing a heat transfer between the first tube (18) and the second tube (20). The ends (32) of the first tube (18) is off-set with respect to the ends (30) of the first tube (18), so that such ends (30, 32) can be received in an alternate way in insertion holes (34) of the header box (2, 14), said holes (34) being spaced with a constant step (P).