Project Title:

Spacecraft Stirling Refrigerator

09.06-1856
Spacecraft Stirling Refrigerator
General Pheumatics Corp.,Western Research Center
7662 E. Gray Road
Scottsdale, AZ
85260
Walker
Graham
601-998-1856
50078
36266
50,000
MSFC

Abstract:

A refrigerator specially developed for use in space-craft provides cooling for low
temperature storage of food and biological samples in the temperature range of 0oF
to 20oF and capcities in the range 1 to 2 KW.  The system operates on the Stirling
refrigeration cycle.  This is a closed, thermodynamic regenerative cycle in which
the gaseous working fluid experiences repeated compression and expansion at different
temperature levels.  The Stirling refrigerator has many advantages over the more
conventional vapor-compression system with an organic working fluid; it can use the
spacecraft life-support gases as the working fluid.  This obviates problems of leakage
and thus relieves the seal problem.  The inventory of fluids on board is reduced.
 Moreover, since the working fluid does not experience a phase change there is no
problem of fluid management of liquids and vapors.  The pressure and temperature
levels can be independently chosen and varied over a wide range to achieve a specific
cooling load profile.  There are no limits to the upper temperature for heat rejection
or the lower temperature for heat absorption.

	Stirling refrigerators are not widely used at near-ambient temperatures but are
the system of choice for miniature cryocoolers in infrared and other cryogenic electronic
applications.  The technology is thus well developed and established with no apparent
fundamental problems awaiting solution.