Two stage Gifford-McMahon cycle cryorefrigerator operating at 20 K

Thirumaleshwar, M and Subramanyama, SV (1986) Two stage Gifford-McMahon cycle cryorefrigerator operating at 20 K. In: Cryogenics, 26 (10). 547 -555.

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Abstract

A two stage Gifford-McMahon cycle cryorefrigerator operating at 20 K is described. This refrigerator uses a very simple ‘spool valve’ and a modified indigenous compressor to compress helium gas. This cryorefrigerator reaches a lowest temperature of 15.5 K; it takes ≈ 50 min to reach 20 K and the cooling capacity is ≈ 2.5 W at 25 K. The cool-down characteristics and load characteristics are presented in graphical form. The effect of changing the operating pressure ratio and the second stage regenerator matrix size are also reported. Pressure-volume (P-V) diagrams obtained at various temperatures indicate that P-V losses form the major fraction of the total losses and this becomes more pronounced as the temperature is decreased. A heat balance analysis shows the relative magnitudes of various losses.

Item Type:	Journal Article
Publication:	Cryogenics
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Keywords:	Cryorefrigerators;Gifford-McMahon cycle;Thermodynamics.
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	22 Jan 2010 08:51
Last Modified:	19 Sep 2010 05:34
URI:	http://eprints.iisc.ac.in/id/eprint/20864

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