A new cryocooler, the M87, has been designed. It combines the well-tested thermodynamics of the M77 cryocooler with features developed to permit the manufacture of large-volume free-piston (linear) compressors. The price of the cryocooler is projected to be $2,000 per unit in lots of 10,000, with availability in the first quarter of 2001. In comparison to the M77 cryocooler, the M87 shows enhanced rated efficiency (20%), improved cooling power, and reduced length and mass. The M87 is rated at 7.5 W lift at 77 K with 150 W(e) input. The enabling market for development of the M87 is the growing need for portable oxygen therapy for home use. The development of significant new markets and new products based on the availability of a low cost cryocooler is anticipated. For instance, in the telecommunications field alone, estimates of the world-wide market by 2005 range from 120,000 to 400,000 units/year.
KeywordsStatistical Process Control Stirling Engine Linear Compressor Free Piston Stirling Cycle
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- 1.U.S. Patent 5,342,176; Method and Apparatus for Measuring Piston Position in a Free Piston Compressor, 8–30-1994.Google Scholar
- 2.U.S. Patent 5,496,176; Method and Apparatus for Measuring Piston Position in a Free Piston Compressor, 3–5-1996.Google Scholar
- 3.U.S. Patent 5,525,845; Fluid Bearing with Compliant Linkage for Centering Reciprocating Bodies, 6–11-1996Google Scholar
- 4.U.S. Patent 4,602,174; Electromechanical Transducer Particularly Suitable for a Linear Alternator Driven by a Free-Piston Stirling Engine, 7–22-1986.Google Scholar
- 5.U.S. Patent 5,642,088; Magnet Ring Support, 6-24-97.Google Scholar
- 9.Van der Walt, N.R., and R.Z. Unger, “Linear Compressors—A Maturing Technology,” Proceedings 45th International Appliance Technical Conference, University of Wisconsin, Madison, Wisconsin (May 1994).Google Scholar
- 10.Unger, Reuven, “Development and Testing of a Linear Compressor Sized for the European Market,” Presented at International Appliance Technology Conference, Purdue University, West Lafayette, Indiana, May 10–12, 1999. Available at: http://www.sunpower.com/techpapers/pub74/iatc99.html
- 11.Lee, H.K., G. Y. Song, E.P. Hong, K.B. Park, J. Y. Yoo, and W.H. Jung, “Development of the Linear Compressor for a Household Refrigerator,” to be presented at the 2000 International Compressor Engineering Conference, Purdue University, West Lafayette, Indiana. (July 25–28, 2000).Google Scholar
- 12.U.S. Patent 5,592,073; Triac Control Circuit, 1-7-97.Google Scholar
- 13.DC Centering of Free Piston Machine, U.S. Patent application pending.Google Scholar
- 14.Gas Bearing and Method of Making a Gas Bearing for a Free Piston Machine, U.S. Patent application pending.Google Scholar
- 15.Heat Exchanger and Method of Constructing Same, U.S. Patent application pending.Google Scholar
- 16.SAUCE, Sunpower’s proprietary Stirling design software.Google Scholar