[labnetwork] Temperature specification for facility process chilled water

[Dennis Schweiger]

Iain,

good morning.  We run nothing for a corrosion inhibitor, or biocide, in
either system.  We are running a side stream UV lamp.  Haven't had any
problems with corrosion, or algae in either system.  Both are open tank
return, so there's essentially zero back pressure, though that shouldn't
matter.  Polishing is done with a pair of DI tanks that pass about 4-6GPM
as needed from the high pressure side, right back into the tank.  We
measure resistivity on the high pressure side.  One system has been
operational since 2007 (150GPM), the other (200GPM) probably twice that
long.  We've had zero problems with either system.

Dennis

734.647.2055 Ofc

"People can be divided into 3 groups - those that make things happen, those
that watch things happen, and those that wonder what happened."  Within
which group do you belong?

On Tue, Sep 15, 2015 at 2:16 AM, Anteney I.M. <I.M.Anteney at soton.ac.uk>
wrote:

> Denis,
>
> I'm particularly interested in your comment about polishing the loops to
> get 1 mega-ohm resistance as we have struggled to do this especially when
> we dose the system with biocide and corrosion inhibitors. What are you
> using to polish the system, what inhibitors/biocides do you use and how do
> these affect the conductivity.
>
> Regards
>
> Iain
>
> Cleanroom Manager
> University of Southampton
>
> Sent from my iPhone
>
> On 15 Sep 2015, at 00:36, Dennis Schweiger <schweig at umich.edu<mailto:
> schweig at umich.edu>> wrote:
>
> Vito,
>
> here at UofMichigan, one of our PCW systems runs about 62.5F (16.9C) with
> a daily deviation of about 1F. The second runs about 59-60F (15C).  It too
> has a daily deviation of about 1F.  For both systems we may see a seasonal
> deviation of 3-4F as the main chiller plant transitions from "free cooling"
> to the use of chillers to create cooling water for the campus wide loop.
> We also "polish" both loops to 1 meg-ohm so that we have a "high
> resistance" in the RF cooling circuits.
>
> Dennis Schweiger
> University of Mighigan/LNF
>
> 734.647.2055 Ofc
>
> On Fri, Sep 11, 2015 at 3:47 PM, Vito Logiudice <
> vito.logiudice at uwaterloo.ca<mailto:vito.logiudice at uwaterloo.ca>> wrote:
> Dear Colleagues,
>
> The process chilled water loop in our cleanroom has consistently
> oscillated between ~15.4C and ~17.2C over a span of roughly 10 minutes. Our
> Plant Operations group is looking into the possibility of tightening this
> up for us by tuning the control sequence. They have asked for guidance on
> an acceptable specification.
>
> In light of this I would appreciate hearing from you as to your facility’s
> PCW temperature target and tolerance. Thank you much.
>
> Best regards,
> Vito
> --
> Vito Logiudice  P.Eng.
> Director of Operations, Quantum NanoFab
> University of Waterloo
> Lazaridis QNC 1207
> 200 University Avenue West
> Waterloo, ON           Canada N2L 3G1
> Tel.: (519) 888-4567  ext.
> 38703<tel:%28519%29%20888-4567%20%C2%A0ext.%2038703>
> Email: vito.logiudice at uwaterloo.ca<mailto:vito.logiudice at uwaterloo.ca>
> Website: https://fab.qnc.uwaterloo.ca
>
>
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