Skip to main content

NOTICE: Due to a lapse in annual appropriations, most of this website is not being updated. Learn more.

Form submissions will still be accepted but will not receive responses at this time. Sections of this site for programs using non-appropriated funds (such as NVLAP) or those that are excepted from the shutdown (such as CHIPS and NVD) will continue to be updated.

U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Temperature instability comparison of micro- and mesoscale Joule-Thomson cryocoolers employing mixed refrigerants

Published

Author(s)

Peter E. Bradley, Ray Radebaugh, Ryan J. Lewis, Mu Hong Lin, Yung-Cheng Lee

Abstract

Previously we demonstrated cryogenic cooling in a Joule-Thomson microcryocooler (MCC) with mixed refrigerants operating at pressure ratios of 16:1 that achieved stable temperatures of 140 K with transient temperatures down to 76 K with precooling of the refrigerant to 240 K. Pre-cooling improves the minimum enthalpy difference, (ΔHT)min compared with pure fluids. Micro-scale compressors have been unavailable to meet 16:1 ratios. By reducing the ratio to 4:1 mini-compressors become viable in the near term. Utilizing mixed refrigerants optimized for 4:1 pressure ratios we compare the performance stability of this micro-JT employing a 25mm long multichannel glass fiber heat exchanger (outer low pressure capillary ID/OD=536µm/617µm, inner high pressure channels ID/OD=75µm/125µm) with a scaled up (mesoscopic) version employing a 20cm long single channel stainless steel heat exchanger (outer low pressure channel ID/OD=580µm/760µm, inner high pressure channel ID/OD=150µm/266µm). This easy to fabricate and modify meso-scale version was fabricated to investigate the temperature instabilities of mixed refrigerants for similar operating conditions but for proportionally higher flows of ~30 cm3/min. compared with ~10 cm3/min. We compare measured pressures, flow rates, temperatures, and stabilities for both micro- and meso-JT cryocoolers to better understand the causes for the temperature instabilities within the micro-JT cryocooler.
Proceedings Title
Cryogenic Engineering Conference of the Cryogenic Engineering Conference and International Cryogenic Materials Conference 2011
Volume
1434
Issue
690
Conference Dates
June 13-17, 2011
Conference Location
Spokane, WA

Keywords

Cryocooler, Joule-Thomson, micro-cryocooler, micro-JT, mixed refrigerants.

Citation

Bradley, P. , Radebaugh, R. , Lewis, R. , , M. and Lee, Y. (2011), Temperature instability comparison of micro- and mesoscale Joule-Thomson cryocoolers employing mixed refrigerants, Cryogenic Engineering Conference of the Cryogenic Engineering Conference and International Cryogenic Materials Conference 2011, Spokane, WA, [online], https://doi.org/10.1063/1.4706980 (Accessed October 2, 2025)

Issues

If you have any questions about this publication or are having problems accessing it, please contact [email protected].

Created June 13, 2011, Updated November 10, 2018
Was this page helpful?