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Title: Cryo Utilities Room Cooling System

Technical Report ·
DOI:https://doi.org/10.2172/1031148· OSTI ID:1031148

Many of the mechanical equipment failures at the Laboratory are due to the loss of cooling water. In order to insure the proper operating temperatures and to increase the reliability of the mechanical equipment in the D0 Cryo Utilities Room it is necessary to provide an independent liquid cooling system. To this end, an enclosed glycoVwater cooling system which transfers heat from two vane-type vacuum pumps and an air compressor to the outside air has been installed in the Cryo Utilities Room. From the appended list it can be seen that only the Thermal Precision PFC-121-D and Ingersoll-Rand WAC 16 deserve closer investigation based on price. The disadvantages of the WAC 16 are that: it runs a little warmer, it requires more valving to properly install a backup pump, inlet and outlet piping are not included, and temperature and pressure indicators are not included. Its only advantage is that it is $818 cheaper than the PFC-121-D. The advantages of the PFC-121-D are that: it has automatic pump switching during shutdown, it has a temperature regulator on one fan control, it has a switch which indicates proper operation, has a sight glass on the expansion tank, and comes with an ASME approved expansion tank and relief valve. For these reasons the Thermal Precision PFC-121-D was chosen. In the past, we have always found the pond water to be muddy and to sometimes contain rocks of greater than 1/2 inch diameter. Thus a system completely dependent on the pond water from the accelerator was deemed unacceptable. A closed system was selected based on its ability to greatly improve reliability, while remaining economical. It is charged with a 50/50 glycol/water mixture capable of withstanding outside temperatures down to -33 F. The fluid will be circulated by a totally enclosed air cooled Thermal Precision PFC-121-D pump. The system will be on emergency power and an automatically controlled backup pump, identical to the primary, is available should the main pump fail. The fan unit is used as a primary cooler and the trim cooler cools the fluid further on extremely hot days. The trim cooler has also been sized to cool the system in the event of a total shutdown provided that the pond water supply has adequate pressure. Due to a broken filter, we found it necessary to install a strainer in the pond water supply line. The expansion tank separates air bubbles, ensures a net positive suction head, protects against surges and over pressurization of the system, and allows for the filling of the system without shutting it off. All piping has been installed, flushed, charged with the glycol/water mix, and hydrostatically tested to 55 psi. The condition of all pumps and flow conditions will be recorded at the PLC. It has been decided not to include the regulator valve in the pond water return line. This valve was designated by the manufacturer to reduce the amount of water flowing through the trim cooler. This is not necessary in our application. There is some concern that the cooling fluid may cool the mechanical eqUipment too much when they are not operating or during very cold days. This issue will be addressed and the conclusion appended to this engineering note.

Research Organization:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Organization:
USDOE Office of Science (SC)
DOE Contract Number:
AC02-07CH11359
OSTI ID:
1031148
Report Number(s):
FERMILAB-D0-EN-203; TRN: US201201%%643
Country of Publication:
United States
Language:
English