Advanced Refrigerator for Cooling Cryo-Electronics

Superconducting electronics have the potential to revolutionize digital communications and to improve real-time situational awareness in the battlefield environment, but must operate at cryogenic temperatures. Commercial cryogenic refrigerators are large and inefficient and are unable to meet typical field requirements. Our approach is to develop a tactical hybrid cryocooler that is optimized for operation with cryogenic electronics. The hybrid cryocooler utilizes the Stirling and Brayton refrigeration cycles in an optimum manner that provides high efficiency at all temperature stages. In addition, the expansion work of the refrigeration cycle, which occurs at cryogenic temperatures, is utilized directly to power the cryogenic electronics. This new and innovative feature mitigates the losses associated with (1) transferring the expansion work to ambient temperature where it is typically dissipated, and (2) the parasitic heat loads from the electrical leads that bring power to the cryogenic electronics from ambient temperature. The net result is an extremely efficient system. During the Phase I project, we finalized specifications for the refrigeration system, performed trades to optimize the cycle configuration and operating conditions, designed the mechanical and electrical components, and performed analyses to support our design. During Phase II, we will build and test a critical cryocooler component.