| Properties and Processes for Cryogenic Refrigeration |
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| Objective: |
| Provide the cryogenic refrigeration industry with measurement and modeling technology for evaluating and improving the performance of cryogenic refrigeration systems and to facilitate the development of new and improved refrigeration and heat transfer processes for the temperature range below about 230 K |
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| Description: |
| Cryogenic refrigeration is a multi-billion dollar industry producing the systems required for a vast array of technologies, including the cooling of infrared sensors for surveillance and atmospheric studies, the cooling of superconducting electronics, magnets, and power systems, the cooling of cryopumps for clean vacuums in semiconductor fabrication processes, and the liquefaction of industrial gases. This project builds on NIST's longstanding leadership position in fundamental research and benchmark data focused on the safe and effective use of cryogenic materials and processes. The major outputs are computational models rooted in the fundamental physics of the many processes and the components - heat exchangers, pulse tubes, regenerators, working fluids, etc. - that control cryocooler efficiency and reliability. Measurement systems allowing model validation and evaluation of overall system performance also are provided along with reference data supporting design, control, and performance of systems for cryogenic applications. The tasks included in this project are: “Cryogenic Design Data” and “Cryocooler models”. |
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| Area(s) of Application: |
- Industrial and Analytical Instruments
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| Accomplishments: |
- Properties and Processes for Cryogenic Refrigeration: As part of a CRADA (with a medical device company) we completed measurements on the performance of a simple pulse tube refrigerator for dermatological pens to about –90 ° C. Such temperatures are higher than what has normally been the operating temperature of pulse tube refrigerators, but our modeling predicted temperature performance quite well. Using a compressor with a piston-position sensor we were able to characterize the overall system performance for this device. We found that losses within the compressor were higher than expected; again suggesting needs for improvement in modeling.
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| Future Plans: |
- A book chapter on “Refrigeration for Superconductors” will soon be published in a special IEEE Proceedings on Electronic and Large Scale Applications of Superconductivity .
- We will continue expanding and improving the cryogenic materials database , and developing test methods and improvements in our cryocooler simulation models to address fundamental limitations to the ef ficiency of cyrocooler systems
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| Recent publications: |
- Ray Radebaugh, “The Development and Application of Cryocoolers Since 1985,” Proc. Conf. On Cryogenics and Refrigeration (ICCR2003), Hangzhou , China , October, 2003.
- P. E. Bradley, R. Radebaugh, R. Baily, and M. Haas “Comparison of Measurements and Models for a Pulse Tube Refrigerator to Cool Cryo-Surgical Probes,” Cryocoolers 13, Plenum Press (2004) in press.
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| Other related project work: |
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| Principal Investigator:
Ray Radebaugh |
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