[labnetwork] FW: Temperature specification for facility process chilled water

[Miller, Timothy J]

Iain,

Normally Jeff Kuhn would answer this, but he is out this week on family business.

All of the components in our PCW system are stainless steel, CPVC, or fiberglass.  We haven't really worried about corrosion preventers since the building was commissioned.

In ten years of operation we have had one problem with bacteria.  The system was dosed once with biocide, which was then removed by dilution.

No UV sterilizers or mixed beds.  If there is a catastrophic loss of water we can refill from the RO on the UPW system, which runs 1-2 MegOhmcm.  If the resistivity of the water drops below .95 Meg the system is topped off with concentrate water from the ultrafilters on the UPW system (18.2 Meg) with the excess water overflowing to drain until the resistivity returns to 1.05 Meg.  Very simple and very inexpensive.

Tim

Timothy J. Miller
Purdue University
Birck Nanotechnology Center
1205 West State Street
West Lafayette, IN 47907-2057
765-427-4712


-----Original Message-----
From: labnetwork-bounces at mtl.mit.edu [mailto:labnetwork-bounces at mtl.mit.edu] On Behalf Of Anteney I.M.
Sent: Tuesday, September 15, 2015 2:16 AM
To: Dennis Schweiger
Cc: Vito Logiudice; labnetwork at mtl.mit.edu
Subject: Re: [labnetwork] Temperature specification for facility process chilled water

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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