Dear AMMRL members,
Eighteen people have answered my recent question on cryo probe Helium
compressor cooling method. A few people like me have the same question
and have asked that I post a summary. Here it is:
Ten people have or will get outdoor air cooled compressors. Most of
these people have their compressors working well for sometime now and
are satisfied. The main concerns are higher cost on both installation
and maintenance. A few people are concerned about occasional shutdowns
or insufficient performances due to extreme temperature outside. One
person warned me about the necessary cleaning that should be done
periodically. Cleaning of the grime, leaves, and trash etc. on the
grille requires the power be shut off.
Five people use chill water loop from the building that is already
available to them, one uses house built chill water loop. About half of
these people are satisfied with the performance, half are concerned
about the hardness and dirtiness of the water. Frequent cleaning and
filter changing are required as the result of the poor water quality.
Some complained about the reduced water flow and temperature stability
due to heat load of the building during peak season. I was warned by
several people that by using building's chill water loop we could be
subjected to campus/building's maintenance scheduling and other unknown
variables for down time.
Three people had indoor air cooled closed cycle water chillers (the
water chillers are made either by Thermo NESLAB or by Haskris). The
major problem for indoor air cool is how to get rid of the 8 kW of heat
that gets dumped in the room. These people have their unit put in a
closet, or out on the hall, or in the room with special duct work that
draws heat to the building's return air vent. Noise is another concern
with this type of cooling.
Thank you so much David Vander Velde, George Furst, Jeff Walton, Phil
Dennison, George Sukenick, Jerry Hirschinger, Michael Jablonsky, Andrew
Staley, Alex Kurochkin, Ian Whitcombe, Tim Claridge, Bob Berno, Joseph
Dumais, Yongbo Zhang, Andrew Lewis, Martha Morton, Mike Blumenstein, and
Robert Meinecke. You are all very kind and helpful!
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My original question:
Dear AMMRL members,
We are doing site planning for a Bruker 500 MHz cryo probe. Our biggest
problem is what type of cooling to use for the Helium compressor.
Bruker offers three types of Helium compressors: indoor water cooling,
indoor air cooling, and outdoor air cooling. The best way of indoor
water cooling is to connect to the building's chilling water loop, but
our campus would charge lots of money to bring chilling water from the
sub basement to the ground level where we are. Tap water cooling is an
alternative but our campus is against it and our water is too hard
anyway, it failed the hardness test even after filtration. Another way
of water cooling is to get a closed cycle water chiller but it will also
need either water or air to dissipate the heat. This could be a noise
source if put indoors. The indoor air cooled compressor would dump lots
of heat in the room and it's noisy. The outdoor air cooled compressor
is what Bruker recommended, and it's quite expensive. About half of the
cost is the outdoor air cooled compressor, and another half is the long
transfer line goes from the room to outside.
If any of you out there have gone through this site planning headache
could you please give any advice you may have. It would be very helpful
if you could describe what kind cooling method you use and how well it
has been performing. Also, what brand of closed cycle water chiller are
you using if you have one?
Thanks in advance!
Wei
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Wei Wycoff
NMR Facility Coordinator
125 Chemistry Building
601 S. College Ave.
University of Missouri-Columbia
Columbia, MO 65211
Phone: (573) 882-3291
Fax: (573) 882-2754
Email: WycoffW_at_missouri.edu
Received on Tue May 29 2007 - 16:42:48 MST