Miniaturization of Thermoacoustic Expander for 50 mW Recuperative Coolers Run Below 40 K

The objective of this project is to develop a novel expander that can increase the efficiency of cryocoolers for IR sensors at very low temperatures and in remote cooling and across gimbal applications. Miniature Thermoacoustic Expanders (MTAE) that employ high energy acoustic waves generated with no moving parts at the cold expander to produce efficient cooling over a wide range of temperatures and reject heat to much higher temperature level. Unlike JT expanders which are irreversible and limited by their working gas to narrow temperature ranges and typically high pressure ratios, MTAE’s can provide effective cooling for a range of applications even including nanoelectronic components that require very low cooling power for which conventional mechanical turbo or piston expanders are inefficient. MTAE development in Phase II will further extend the technology envelope to smaller scale prototypes and the lower operating temperature range. Successful completion of Phase II will result in the fabrication, test, and delivery of a MTAE prototype unit which is designed for a recuperative cryocooler operating with >1W of cooling power below 77K.