Compact Thermosyphon Heat Exchanger for Electric Machine Cooling
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Solution Overview
Problem
Existing electric machine cooling technologies, such as those using heat-pipes and thermosyphon techniques, often result in bulky cooling elements that are not scalable and efficient, particularly in environments where water is not readily available or must be avoided.
Innovation Solution
A compact thermosyphon-based heat exchanging structure is employed, utilizing a single module with parallel conduits and headers, where a two-phase working fluid transports heat through natural convection, allowing for efficient cooling of clean air using dirty ambient air, with low pressure drop and scalable design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If thermosyphon heat exchanging elements are used to cool electric machines, then cooling efficiency is improved, but the size and volume of the cooling system becomes bulky
Solution Approach 1:
The heat exchanging unit is divided into multiple parallel conduits (evaporator conduits and condenser conduits) that are arranged in parallel between upper and lower header tubes. This segmentation allows the heat exchange function to be distributed across multiple smaller channels, improving cooling efficiency while maintaining a compact overall structure.
Solution Approach 2:
The patent transitions from single large-volume thermosyphon elements to a multi-conduit parallel arrangement that utilizes three-dimensional space more efficiently. The conduits are positioned vertically between header tubes, creating a compact modular structure that achieves high cooling capacity without proportional increase in volume.
2Productivity
If water-to-air heat exchangers are used for cooling, then cooling performance is improved, but the system becomes unsuitable for environments where water is not available or must be avoided
Solution Approach 1:
The heat exchanging unit is designed as a universal cooling system that can operate with various coolant types. The parallel conduit structure with header tubes can accommodate different fluids (air, water, or other coolants) without requiring fundamental design changes, making it adaptable to marine environments, industrial settings, and applications where water availability varies.
Solution Approach 2:
The patent introduces a flexible coolant selection approach where the heat exchanging unit can use different intermediary substances depending on the application environment. The system design allows substitution of water with air or other coolants while maintaining effective heat transfer through the parallel conduit structure.
3Adaptability or versatility
If air-to-air heat exchangers are used, then environmental adaptability is improved, but the cooling efficiency and heat transfer capability deteriorates
Solution Approach 1:
The cooling system is segmented into multiple parallel conduits that increase the total heat transfer surface area. This segmentation allows air-to-air heat exchange to be sufficiently efficient by distributing the heat load across many smaller channels, each contributing to the overall cooling capacity.
Solution Approach 2:
The patent uses multiple identical parallel conduits as copies of the basic heat exchange unit. Each conduit functions as a replicate of the same structure, and their combined effect achieves high cooling efficiency while maintaining the simplicity and adaptability of air-to-air heat exchange.
4Volume of stationary object
If compact heat exchanging units are designed, then volume is reduced, but the heat exchange efficiency and cooling capability deteriorates
Solution Approach 1:
The compact heat exchanging unit achieves high efficiency through segmentation into multiple parallel conduits. Each conduit provides heat exchange surface area, and their parallel arrangement within a compact volume between header tubes creates a high surface-area-to-volume ratio, maintaining efficient heat transfer in a small footprint.
Solution Approach 2:
The patent employs a nested arrangement where multiple conduits are positioned concentrically or adjacently between the upper and lower header tubes. This nesting approach maximizes the use of available space, allowing multiple heat exchange surfaces to be packed into a compact volume without interfering with each other's thermal performance.
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 solution provides a compact, efficient, and scalable cooling system that effectively transfers heat from the electric machine to ambient air, reducing noise and energy consumption while maintaining high cooling performance, even in environments where water is not accessible.
Implementation Method 1
The two-phase working fluid inside the heat exchanging unit transports the heat through the heat exchanging unit by natural convection
Implementation Method 2
The heat exchanging unit also has an evaporating section formed at one side of the parallel conduits and a condensing section formed at an opposite side of the parallel conduits
Data Source
Figure 1~2
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AI summary
An electric machine comprises a closed chamber (22A, 22B) with a wall (26) and enclosing a stator (30), a rotor (32) and a first fluid (F1) and a heat exchanging unit (10) stretching from the chamber through the wall to a fluid transporting passage (24). The heat exchanging unit comprises conduits provided in a loop, containing a working fluid and equipped with evaporator channels and condenser channels, first heat transfer elements inside the chamber for transferring heat from the first fluid to the working fluid via the evaporator channels and second heat transfer elements in the passage for transferring heat out of the working fluid via the condenser channels to a second fluid (F2), a first fluid propagating unit (38) inside the chamber forcing the first fluid to circulate and a second fluid propagating unit in the passage forcing the second fluid to flow past the second heat transfer element.