Intelligent Current Lead for Cryogenic Heat Leak Reduction
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Solution Overview
Problem
Current current lead designs for cryogenic applications face challenges in minimizing heat leak and optimizing electrical power usage due to inefficiencies in heat transfer and ohmic heating, particularly when connecting room temperature sources to cryogenic devices.
Innovation Solution
The development of an intelligent current lead device that utilizes adjustable parameters such as cross-sectional area, length, and material composition, along with active and passive control algorithms, to optimize heat transfer and electrical power management, incorporating high-temperature superconducting sections and gas/vapor cooling to minimize heat flux and ohmic heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a normal metal conductor is used for current lead connection from room temperature to cryogenic temperature, then electrical current can be transmitted, but heat leak increases due to thermal conduction and ohmic heating
Solution Approach 1:
The current lead is divided into multiple discrete current elements that can be independently engaged or disengaged. Each element has its own switch, allowing selective activation based on operational requirements. This segmentation enables the system to use only the necessary number of conductive paths, reducing overall heat leak while maintaining electrical functionality.
Solution Approach 2:
The current lead system incorporates dynamic control through switches that can engage or disengage individual current elements based on real-time operational conditions. This dynamic adjustment allows the system to optimize heat leak reduction by activating only the required number of current elements, transforming a static structure into an adaptable thermal management system.
2Loss of energy
If multiple current elements are used to reduce heat leak, then thermal efficiency improves, but device complexity increases due to additional switches and control mechanisms
Solution Approach 1:
Each current element is designed with integrated switch control that can serve multiple functions: electrical isolation, thermal management, and fault protection. The switches not only control current flow but also provide thermal breaks, eliminating the need for separate thermal isolation mechanisms and reducing overall system complexity despite having multiple elements.
Solution Approach 2:
The system dynamically changes operational parameters by engaging or disengaging specific current elements based on load requirements. When high current is needed, more elements are activated; when low current or no current is needed, elements are deactivated to minimize heat leak. This parameter adjustment optimizes the balance between electrical performance and thermal efficiency.
3Loss of energy
If current elements are disengaged to minimize heat leak at zero current flow, then thermal efficiency improves, but electrical connection reliability may be affected
Solution Approach 1:
The system incorporates redundant current elements that can be pre-positioned and quickly engaged if needed. When disengaged for thermal efficiency, the standby elements provide a safety cushion, ensuring that electrical connection reliability is maintained through rapid re-engagement capability without compromising the thermal benefits of the disengaged state.
Solution Approach 2:
The control system monitors operational conditions and provides feedback to determine when current elements should be engaged or disengaged. This feedback mechanism ensures that disengagement for heat leak reduction occurs only when appropriate, and that re-engagement happens promptly when electrical connection is needed, maintaining reliability while optimizing 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
The intelligent current lead device effectively reduces heat leak and electrical power consumption by dynamically adjusting its configuration to match changing load conditions, providing minimal heat transfer and efficient operation across varying temperature differentials.
Implementation Method 1
incorporating high-temperature superconducting sections and gas/vapor cooling to minimize heat flux and ohmic heating
Implementation Method 2
A more energy efficient current lead design uses forced flow gas, vapor, or liquid cooling along the length of the lead which from the warmer temperature reservoir to the lower temperature reservoir
Implementation Method 3
A common type of current lead is a so-called 'cryogenic vapor cooled lead' in which the vapor evolved from an evaporating liquid cryogen bath (e.g. helium, hydrogen, neon, air, nitrogen, etc.) due to heat influx at the bottom of the current lead flow upwards, exchanges heat with the current lead, and cools the remaining portions of the current lead
Implementation Method 4
the vapor evolved from an evaporating liquid cryogen bath (e.g. helium, hydrogen, neon, air, nitrogen, etc.) due to heat influx at the bottom of the current lead
Data Source
AI summary
An intelligent current lead device, its design, fabrication, and methods of operation are described in this disclosure. The intelligent current lead device described in this disclosure electrically and thermally connects and disconnects one or more power sources or loads operating at one temperature reservoir with one or more machines or devices operating at either the same or a different temperature reservoir. The intelligent current lead can operate in either an active mode or passive mode. The intelligent current lead device may incorporate the use of multiple types of diagnostic sensors and instrumentation, which can be monitored, interpreted, and analyzed. The program logic of the intelligent current lead may be used to interpret the data obtained from the diagnostic sensors and instrumentation in order to adjust/actuate/switch the current lead so as to optimize its configuration to respond to requirements of an electrical load that changes with time. There are many applications that the intelligent current lead can be used in conjunction with including but not limited to: superconducting magnets, transformers, power cables, energy storage, motors, generators, fault current limiters, circuit breakers, fusion magnets, accelerator magnets, MRI magnets, NMR magnets, induction heaters, magnetic separators, among other applications.