Engineering topics

Creel, Jonathan

Publications and source records attributed to Creel, Jonathan.

4 records

DOE OSTI2023

End Station Refrigerator 2 Cryoplant at JLAB

The future operation of the 4 kW 15 Kelvin MOLLER experiment at Jefferson lab necessitates an increase of cryogenic capacity at the End Station Refrigerator. The current plant is the former 1.5 kW (4.5 K) ESCAR plant that has been operating at Jefferson Lab since 1995. The existing 1.5 kW plant is not able to support the load for MOLLER and will be replaced with a refurbished plant comprised of the cold box and compressors of the 4 kW ASST-A plant from the Superconducting Super Collider in Texas. This paper outlines the assembly, repair and modifications made to the cold box, along with the design of the plant as a whole and its integration into the existing distribution system.

Perry, Christopher↗

DOE OSTI2019

CHL1 2K COLD BOX REPLACEMENT

There is growing evidence showing that the cold compressors in the Modified Sub-atmospheric Cold Box (SC1/SCM) of the JLab Central Helium Liquefier (CHL) are approaching the end of their life. Their replacement parts are no longer available due to obsolescence, thus placing the Physics program at serious risk. A new sub-atmospheric cold box (SC1R), which hosts five technologically superior, water-cooled cold compressors and a similar 4K-2K refrigeration recovery heat exchanger, was funded in July 2017, to replace the existing 2K cold box. The design of the new 2K cold box and the external support system have been completed allowing the project to enter the fabrication and assembly phase, which will be completed here at JLab. We present the design, fabrication, installation and commissioning schedule of the new 2K cold box.

Yang, Shirley↗

DOE OSTI2017

Commissioning and Testing of a new 4.5K Cold Box for JLab Cryogenic Test Facility

A new 4.5K cold box at Jefferson Lab (JLab) Cryogenic Test Facility (CTF) was recently installed and commissioned to upgrade the existing 4.5 K refrigeration system and work in parallel with the existing 4.5 K cold box. This new 4.5 K cold box is equipped with two turbo-expanders and, at its maximum capacity condition, it is expected to support at least 6.6 g/s of helium liquefaction or 650 W of refrigeration at 4.5 K. It can also handle up to 10 g/s 30 K return flow for 2 K refrigeration recovery that supports cryo-module and superconducting cavity testing. Performances of the cold box at its maximum capacity conditions as well as several other operating modes were tested for acceptance. Finally, we will briefly review the new 4.5 K cold box design features and discuss the commissioning and performance testing results.

42 ENGINEERING↗

NASA NTRS2008

Floating Pressure Conversion and Equipment Upgrades of Two 3.5kw, 20k, Helium Refrigerators

Two helium refrigerators, each rated for 3.5KW at 20K, are used at NASA s Johnson Space Center (JSC) in Building No. 32 to provide cryo-pumping within two large thermal-vacuum chambers. These refrigerators were originally commissioned in 1996. Equipment refurbishment and upgrades to the controls of these refrigerators were recently completed. This paper describes some of the mechanical and control issues that necessitated the equipment refurbishment and controls change-over. It will describe the modifications and the new process control which allows the refrigerators to take advantage of the Ganni Cycle "floating pressure" control technology. The upgrades -- the controls philosophy change-over to the floating pressure control technology and the newly refurbished equipment -- have greatly improved the performance, stability, and efficiency of these two refrigerators. The upgrades have also given the operators more information and details about the operational status of the main components (compressors, expanders etc.) of the refrigerators at all operating conditions (i.e.: at various loads in the vacuum chambers). Capabilities, configuration, and performance data pre, and post, upgrading will be presented.

Homan, Jonathan↗