Flexible Aerogel as a Superior Thermal Insulation for Superconductor Technology

High temperature superconducting (HTS) cables can strengthen and improve the national electrical distribution infrastructure. These HTS cables require sufficient cooling to overcome inherent low-temperature heat loading. For optimum efficiency, HTS wires should have an operating temperature of 63-83 K, which requires forced-flow liquid nitrogen cooling. Currently, the cryostats used for cooling thermally insulate the liquid nitrogen coolant through the use of a high vacuum ¿superinsulation,¿ which consists of reflecting foils and spacer materials. This high vacuum, multi-layer insulation (MLI) suffers from several issues, including vacuum integrity, damage during installation, and degradation over time. This project will develop a compression-resistant aerogel thermal insulation package to replace the compression-sensitive MLI in cryostats for HTS cables. The material properties of these aerogels will minimize, if not eliminate, the heat leaks which can have catastrophic effects on the cable¿s resistance. Phase I will focus on designing and analyzing an optimized aerogel package, testing aerogel material compatibility with HTS system components, and fabricating and testing a prototype solution in a laboratory-scale pipe apparatus to measure the rate of heat invasion. Commercial Applications and other Benefits as described by the awardee: The improved insulation should lead to a cryogenic system that enables HTS power cables to meet the increasing energy needs of a growing economy. The aerogel insulation packages should provide tremendous savings in terms of reliability (heat invasion less than 1 W/m), ease of installation, shorter lead times, and reduced cost (less than $200/m). The technology also has promise for use in other cryogenic applications, including medical devices (i.e. MRI components), cryogenic transfer lines, storage tanks, and transportation vessels for the LNG industry.