Abstract
This paper describes the results obtained with an experimental prototype of a new type of cryocooler. The cycle employed by the device (a GM/magnetic cycle) uses two thermodynamically active substances: a compressible gas (helium) and a paramagnetic solid (Gadolinium Gallium Garnet or GGG). The two substances alternately regenerate one another, thereby overcoming the low temperature thermal saturation associated with a GM cycle while producing more refrigeration than a regenerative magnetic cycle. The experimental prototype utilizes a unique regenerative upper stage device to maintain the warm reservoir temperature seen by the GM/magnetic stage at the required 10–20 K. The pressure in the apparatus is controlled using a room temperature compressor and a system of valves. The device operates at a pressure level which is on the order of 4 atmospheres and uses a pressure ratio of approximately 2. The applied field in the GM/magnetic stage is controlled with a superconducting solenoid and a power supply. The maximum applied field imposed on the paramagnetic regenerator bed is 4 tesla.
The GM/magnetic refrigerator ultimately reached a no load temperature of 4.5 K while rejecting heat at 10.9 K. The device supplied 0.36 W of refrigeration at 6 K while rejecting heat at 15.4 K. The prototype clearly shows that the GM/magnetic cycle is an effective refrigeration cycle below 15 K.
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References
K. D. Timmerhaus, “Recent Trends in Cryocooler Development“, Proceedings of the XIII ‘th International Congress of Refrigeration, 1:233, (1991).
J. L. Smith Jr., “Cryogenic refrigeration for space exploration — a challenge for the futuref”, Proceedings of the XVII’th International Congress of Refrigeration, 1: 2, (1991).
G. Walker and E. R. Bingham, “Low-Capacity Cryogenic Refrigeration”, Clarendon Press, Oxford (1994).
J. A. Barclay, “Magnetic refrigeration for low-temperature applications”, Proceedings of the Third Cryocooler Conference, 1:20, (1984).
G. F. Nellis and J. L. Smith Jr., “Investigation of a magnetically augmented cryogenic refrigerator”, Proceedings of the Eighth Cryocooler Conference, 1:647, (1995).
S. Jeong and J. L. Smith Jr., “Magnetically augmented regeneration in Stirling Cryocooler”, Advances in Cryogenic Engineering, 39B:1399, (1994).
G. F. Nellis, “Magnetically augmented cryogenic refrigeration”, M. I. T. (M.S. Thesis), Cambridge, (1995).
G.F. Nellis and J. L. Smith Jr., “Design of an Experimental Apparatus for Investigation of Magnetically Active Regeneration in the Presence of Cyclic Pressure Variations”, Advances in Cryogenic Engineering, 41: (1995).
G. F. Nellis, “Stirling/magnetic cryocooler”, M. I. T. (Ph.D. Thesis), Cambridge, (1997).
R.A. Fisher, G. E. Brodale, E. W. Hornung, and W. F. Giauque, “Magnetothermodynamics of gadolinium gallium garnet. I. Heat capacity, entropy, magnetic moment from 0.5 to 4.2 K, with fields to 90 kG along the [100] axis”, J. Chem. Phys., 59: 4652, (1972).
G. R. Ghallagher, “Analysis of a Magnetically Active Regnerator”, MIT. (M.S. Thesis), Cambridge, (1986).
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© 1998 Springer Science+Business Media New York
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Nellis, G.F., Smith, J.L. (1998). An Experimental GM/Magnetic Refrigerator. In: Kittel, P. (eds) Advances in Cryogenic Engineering. Advances in Cryogenic Engineering, vol 43. Springer, Boston, MA. https://doi.org/10.1007/978-1-4757-9047-4_223
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DOI: https://doi.org/10.1007/978-1-4757-9047-4_223
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