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Compact Cryogenic High Temperature Superconducting Cable Junction Box
Navy SBIR 2008.1 - Topic N08-078 ONR - Mrs. Tracy Frost - [email protected] Opens: December 10, 2007 - Closes: January 9, 2008 N08-078 TITLE: Compact Cryogenic High Temperature Superconducting Cable Junction Box TECHNOLOGY AREAS: Ground/Sea Vehicles, Materials/Processes ACQUISITION PROGRAM: PEO SHIPS PMS 500 CG(X) DDG-1000 The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), which controls the export and import of defense-related material and services. Offerors must disclose any proposed use of foreign nationals, their country of origin, and what tasks each would accomplish in the statement of work in accordance with section 3.5.b.(7) of the solicitation. OBJECTIVE: Develop a high temperature superconducting (HTS) cable junction box to provide coolant circulation and electrical feed through for a low voltage DC HTS cable. DESCRIPTION: Superconductivity has become of interest in recent years to the Department of Energy (DoE) and the Department of Defense (DoD) for its characteristic of power density. The DoE has led a significant effort to develop high temperature superconducting (HTS) wire for use in power cable demonstrations. The cable projects are typically maintained by sub cooled liquid nitrogen which also provided the benefit of electrical insulation. Nitrogen is usually pumped down the HTS cable and circulated back to the refrigeration site through a return cryostat. The Navy has leveraged off of the DoE investment in wire development through various motor and generator programs demonstrating the benefits of HTS in propulsion applications. The Office of Naval Research (ONR) has also funded the feasibility study and subsequent land based demonstration of concept of a gaseous helium cooled HTS degaussing system. The HTS degaussing system consists primarily of three components: a cryogenic refrigeration system, current supply, and HTS cable. The HTS cable consists of the HTS wire surrounded by a cryostat to reduce heat leak into the system. The cable consists of 20-40 superconducting tapes and both the electrical current and gas cooling needs to enter and exit the cryostat at cryogenic electrical junction boxes. Different types of compact, very low heat leak junction boxes would be desired depending on the ship class and installation techniques planned. An integrated cable termination junction both with the cryocooler and circulation fan would be one option. Another option would be a cable termination junction box that accepts input for both cooling flow and electrical power to the HTS cable from a remote location. Both types of junction boxes need to send coolant down the cryostat and return from the opposite side while allowing electrical continuity between each individual turn of superconductor. The use of standard vacuum components will not meet the Navy needs for this program. This is a complex problem and innovative approaches to reduce heat loads on the cryogenic system and overall size of the junction boxes are required. PHASE I: Identify concepts to achieve gas flow through the degaussing loop while enabling multiple turns of superconductor to pass through the junction box. Determine the feasibility of incorporation of a helium fan and cryocooler cold in a single junction box while minimizing parasitic heat leaks. Complete preliminary designs of shipboard cryogenic HTS cable junction box. PHASE II: Develop and demonstrate full scale prototypes of the compact HTS junction boxes. The prototype should successfully demonstrate proper operation and be verified compliant to military shock and vibration standards. PHASE III: Transition this technology to commercial and military market. The DDG-1000 and CG(X) platforms will receive Advance Degaussing systems (ADS) to improve the capability of these platforms. PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: The resulting compact cryogenic high temperature superconducting junction box will have application in the expanding markets of cryogenics and superconductivity. This junction box will benefit superconducting projects as the transition from the research environment to field use through simplification of electrical and cooling incorporation. Markets for this junction box include research laboratories, electrical utility cables, and Navy ship HTS degaussing systems. REFERENCES: 2. Fitzpatrick, B. "High Temperature Superconducting Degaussing System Assessment," ASNE Day 2005, April 2005. 3. Snitchler G., Gamble B., Kalsi S.S., "The performance of a 5 MW high temperature superconductor ship propulsion motor" Applied Superconductivity, IEEE Transactions on Volume 15, Issue 2, Part 2, June 2005 Page(s):2206 � 2209 4. Fitzpatrick, Kephart, Golda. "High Temperature Superconducting Degaussing - Cooling two HTS coils with one cryocooler for the Littoral Combat Ship." Advances in Cryogenic Engineering, July 2007 5. Fitzpatrick, Kephart, Golda. "Characterization of Gaseous Helium Flow Cryogen in a Flexible Cryostat for Naval Applications of High Temperature Superconductors." IEEE Transactions on Applied Superconductivity. (Applied Superconductivity Conference AUG 2006). KEYWORDS: high temperature superconductor, cryogenic, superconductivity, HTS, power cables, degaussing, DC, junction box, cryocooler, current feed through TPOC: George Stimak
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