Cooling Topologies for Superconducting Power Systems: I. Short Distance Electric Distribution

In this and in accompanying reports, the topologies for cooling superconducting systems are investigated. The goal is to explore options that allow for flexibility of operation, low temperature rise in the superconductor and low refrigerator power consumption. A focus of this report is the study of means for cooling distribution systems with cryogenic loads dominated by current lead loss. Use of multiple fluids to decreased the refrigerator power requirements are described, and potential alternative candidate fluids are proposed.