ASA 125th Meeting Ottawa 1993 May

4aPA2. Thermoacoustic life sciences refrigerator.

Steven L. Garrett

D. Felipe Gaitan

David K. Perkins

Dept. of Phys. and Space Systems Academic Group, Naval Postgraduate School, Code PH/Gx, Monterey, CA 93943

D. Andrew Helseth

Actran Systems, Orlando, FL

This thermoacoustic refrigerator is being built to preserve biological samples (blood, urine, etc.) during Space Shuttle operations. It employs two high-power electrodynamic drivers capable of generating 60 W of acoustic power each, two ``stacks,'' and four internal heat exchangers in order to produce 700 BTU/h (205 W) of cooling in the refrigerator mode at 4 (degrees)C and 400 BTU/h (117 W) of cooling in the freezer mode at -22 (degrees)C. The working fluid is a 2-MPa mixture of He and Xe gas. Both hot and cold heat exchangers use circulating fluids to remove heat from the insulated sample enclosure and exhaust enthalpy from the engine. This talk will describe the acoustical design and electronic control systems that permit long-term autonomous operation while on orbit. Except for the fact that the entire systems operates from a 28-V[sub dc] power supply, it is not unlike a typical small household refrigerator. [Work supported by NASA---Life Sciences Division and managed by General Electric Government Systems.]