Superconducting Machine Cooling System with Dual-Mode Rotor
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Superconducting electrical machines require a long cool-down period from ambient to cryogenic temperatures, which is a commercial disadvantage due to their large size and thermal mass, making them uneconomic to keep cooled permanently and hindering widespread adoption.
Innovation Solution
A cryogenic cooling system that operates in two modes: during cool-down, it provides coolant to both the inner and outer rotor, increasing heat transfer by using a higher flow rate and potentially colder coolant, and during operation, it reduces coolant flow to the inner rotor only, optimizing heat transfer for steady-state conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the cooling system provides coolant to both inner rotor and outer rotor during cool-down, then the cool-down time is reduced, but the system complexity and cost increase
Solution Approach 1:
The rotor is divided into two separate parts: an inner rotor containing superconducting components and an outer rotor containing conventional components. Each part can be cooled independently, allowing the cooling system to target only the necessary superconducting components during operation, thereby reducing cool-down time without permanently increasing system complexity
Solution Approach 2:
The cooling system is designed to dynamically adjust coolant flow distribution between the inner and outer rotors based on operational requirements. During cool-down, coolant flows to both rotors simultaneously to maximize cooling efficiency and reduce time. During steady-state operation, coolant flow is directed only to the inner rotor, optimizing performance while reducing energy consumption and system complexity
2Temperature
If the cooling system provides coolant to both inner rotor and outer rotor during cool-down, then heat transfer is increased, but energy consumption increases
Solution Approach 1:
During the cool-down phase, the cooling system applies excessive cooling action by providing coolant to both inner and outer rotors simultaneously, maximizing heat transfer rate to rapidly reduce temperature. During steady-state operation, only partial cooling is applied to the inner rotor at the exact level needed to maintain superconducting temperature, minimizing energy consumption while preserving the beneficial high heat transfer capability when required
3Reliability
If the machine is kept cooled permanently, then the superconducting state is maintained, but operational cost increases
Solution Approach 1:
The rotor is segmented into inner and outer parts with different cooling requirements. The inner rotor with superconducting components requires continuous cooling to maintain the superconducting state, while the outer rotor with conventional components does not. This segmentation allows the cooling system to operate only on the necessary inner rotor during steady-state, significantly reducing energy consumption and operational costs while maintaining reliability of the superconducting function
Solution Approach 2:
The cooling system is designed to automatically adjust its operation based on the operational state of the machine. During start-up and transient conditions, both rotors are cooled to ensure stable superconducting operation. During steady-state operation, the system reduces cooling to the inner rotor only, allowing the superconducting components to maintain their state with minimal energy input, thereby reducing operational costs while preserving reliability
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 significantly reduces the cool-down time by increasing heat transfer during the initial cooling phase and optimizing coolant usage, making superconducting machines more economically viable for commercial use.
Implementation Method 1
a two-part rotor having an inner part and an outer part, both parts configured to receive a flow of coolant
Implementation Method 2
the cryogenic system allows at least one of the electrical machine's windings to operate in the superconducting state
Implementation Method 3
The outer rotor may be evacuated so as to be under vacuum during the second mode
Data Source
AI summary
A machine such as a ship's engine has a superconducting component requiring cooling for its operation, and includes a cooling system. The cooling system is operable in first and second modes. In a cool-down phase the cooling system is run in the first mode providing relatively high heat transfer from the superconducting component. On attainment of a desired operating temperature the cooling system is run in the second mode, providing lower heat transfer. This enables a reduced cool-down time of the machine, while allowing economical operation in normal service. The higher level of cooling in the first mode used during the start-up procedure can involve a colder cryogen, or a greater flow of coolant. One way of achieving the latter is to circulate the coolant in normally evacuated regions during the cool-down phase, and then re-establishing the vacuum in these regions for normal service operation.