Superconducting Coil Cooling with Local Cryogen Recondensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional cooling methods for superconducting systems, such as immersion in liquid cryogenic coolants or use of thermal conductors, face challenges like bulkiness, high cryogen consumption, pressure concerns, and temperature gradients, making them inefficient and less suitable for larger coils.
Innovation Solution
A cooling system that uses a local cryogen chamber with a highly thermally conductive means to transfer heat from the superconducting coil to vaporize cryogen, which then acts as a heat transfer medium to a recondensing unit, reducing cryogen quantity and size, and allowing greater flexibility in system design and location of components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a cryogen containing bath is used to immerse the superconducting coil, then heat transfer effectiveness is improved, but the apparatus becomes bulky and requires large quantities of cryogen
Solution Approach 1:
The invention extracts the cryogen from the large immersion bath and relocates it to a compact chamber positioned close to the coil. Only a small amount of cryogen is needed in the chamber, dramatically reducing the overall apparatus volume while maintaining effective heat transfer through the close proximity of the chamber to the coil.
Solution Approach 2:
A highly thermally conductive means is introduced as an intermediary between the coil and the cryogen in the chamber. This mediator efficiently transfers heat from the coil to the cryogen, enabling effective cooling with minimal cryogen volume in a compact configuration.
2Temperature
If a cryogen containing bath is used to immerse the superconducting coil, then cooling performance is improved, but the system requires pressure vessel construction to withstand high pressures from vaporisation
Solution Approach 1:
The invention removes the need for a large pressure-containing bath by extracting the cryogen to a small chamber. The minimal amount of cryogen required in the chamber dramatically reduces vaporisation pressure, eliminating the need for complex pressure vessel construction while maintaining cooling performance.
Solution Approach 2:
The cryogen is concentrated in a local chamber positioned close to the coil rather than distributed in a large bath. This localisation of the cryogen reduces the total volume and pressure requirements, simplifying the overall system design.
3Quantity of substance
If thermal conductors are used to transfer heat from the coil to the cryocooler working fluid, then cryogen quantity is reduced, but significant temperature gradients arise over the conductor length
Solution Approach 1:
The heat transfer path is segmented into two stages: first, a highly thermally conductive means transfers heat over a short distance from the coil to a cryogen chamber; second, the vaporised cryogen itself acts as the heat transfer medium to carry heat away. This segmentation eliminates long thermal conductor paths and associated temperature gradients.
Solution Approach 2:
The invention changes the state of the cryogen from liquid in a large bath to vapor in a controlled chamber, and uses the phase change process to enable efficient heat transfer over distance without relying on long thermal conductors that would create temperature gradients.
4Ease of operation
If thermal conductors are used to transfer heat over significant distances, then cryogen immersion is avoided, but the system becomes unsuitable for larger coils requiring distant cryocooler placement
Solution Approach 1:
Vaporised cryogen is used as an intermediary heat transfer medium to carry heat from the compact chamber (close to the coil) to the cryocooler located at a distance. This allows the cryocooler to be positioned far from the coil without suffering from the temperature gradient problems of long thermal conductors.
Solution Approach 2:
The invention uses the cryogen vapor as a fluid medium to transport heat over distance, replacing solid thermal conductors. This pneumatic/hydraulic approach to heat transfer enables flexible positioning of the cryocooler at significant distances from the coil while maintaining thermal 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
This approach minimizes cryogen usage, reduces pressure concerns, and avoids temperature gradients, enabling more compact and efficient cooling of larger superconducting coils while maintaining effective heat transfer over longer distances.
Implementation Method 1
heat is transmitted by thermal conduction over the relatively short distance to a local cryogen chamber to vaporise cryogen present in the chamber in use
Implementation Method 2
The cryogen absorbs heat from the superconductor, and is vaporised, thus cooling the superconductor
Implementation Method 3
the vaporised cryogen acts as a heat transfer medium to remove heat from the vicinity of the superconducting coil, travelling from the cryogen chamber to a recondensing unit
Implementation Method 4
cryogen located in the chamber and vaporised by heat from the superconducting coil may flow to the cryogen recondensing unit to be recondensed before returning to the chamber
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A superconducting system comprises a superconducting coil (3) mounted in a support (12). The coil is surrounded by a cryogen chamber (17) which is located radially outwardly from the coil (3) on the other side of the support (12). The cryogen chamber is in fluid communication with a cryogen recondensing unit (33) whereby vaporized cryogen may flow from the cryogen chamber (17) to the cryogen recondensing unit (33) to be recondensed in use before returning to the cryogen chamber. Thermally conductive means (25) is arranged to facilitate heat -transfer from the superconducting coil (3) to the cryogen chamber (17) to vaporize cryogen contained therein in use and thereby remove heat from the coil. A thermal conduction path is therefore used to transfer heat from the coil to the cryogen in the cryogen chamber, while vaporized cryogen acts as the heat transfer medium, over the longer distance between the cryogen chamber and the recondensing unit.