Demin Water System
Demin Water System
(OP)
Hi all,
I am in process of designing a chilled demin water system and with some specs here:
Approx 1300 GPM, transient heat load: 10MJ, requirement is provide chilling capacity to dissipate 10MJ within 10 minutes. The design chilled demin water temperature is 50F.
I am thinking having a separate loop for cooling and another separate loop for resin bed (I plan to buy demin water to start and keep "re-cleaning" it along the way). I would like to ask for advise from all of you... about the feasibility of this setup and how to size the bed... and other pointers. THANKS!!!!!!
I am in process of designing a chilled demin water system and with some specs here:
Approx 1300 GPM, transient heat load: 10MJ, requirement is provide chilling capacity to dissipate 10MJ within 10 minutes. The design chilled demin water temperature is 50F.
I am thinking having a separate loop for cooling and another separate loop for resin bed (I plan to buy demin water to start and keep "re-cleaning" it along the way). I would like to ask for advise from all of you... about the feasibility of this setup and how to size the bed... and other pointers. THANKS!!!!!!





RE: Demin Water System
RE: Demin Water System
would you mind elaborate a bit more on: "dissolve the system"? the equipment and devices which cooling is required asks for DI water... Thanks!!
RE: Demin Water System
Is this a completely closed loop (recirculating) system?
If so, why need demin water? Also, please clarify what you mean by demin water (TDS, conductivity).
RE: Demin Water System
In my design I am assuming a closed loop system.
The reason for using demin water (DI water) is the cooling water will be used for cooling some electronics and RF devices... was told that this is a requirement from the manufacturer.
Currently the requirement is conductivity max = 0.2 us/cm and as the cooling water is running past the equipment... it (I think and please correct me if i am wrong) will pick up ions etc and so conductivity will pick up... TDS I am hopeful on 0.2 ppm... please advise! Thanks!
RE: Demin Water System
HDPE is perhaps OK for the tank, but it comes in several grades; an all virgin grade is necessary but don't recall the rest. But tanks are easy to find, and Kynar & Teflon fittings & 316L should be OK. What are the materials of the electronics being cooled, in contact with the water (hope not copper)?
RE: Demin Water System
Yea.. the problem is some ARE copper... since there are quite a bit of devices needed to be cooled so... therefore I figured a resin bed is need to keep the conductivity down... however I am struggling to size it and all the other assocessories that come with it (I am novice to DI system as you can prob. tell by now)... please advise...
Thanks a bunch!!
RE: Demin Water System
RE: Demin Water System
Gary Schreiber, CWS VI
The Purolite Co.
RE: Demin Water System
You need to go back to your equipment supplier and doublecheck the water cooling requirements.
Several items in your post do not make sense.
The flow capacity is unusually large for a cooling system.
Copper components are not recommended for demineralized water service.
Demineralized water is not generally used for cooling water.
RE: Demin Water System
Well, the manufacturer specifically asked for DI water; and the capacity is quite large due to the large number of devices, high power RF equipment, that needs cooling. My current problem is .... more like they have given me a "black box" and I have to design around it, so please advise. THANKS!!!!
RE: Demin Water System
Only a small demineralizer is necessary since the demineralizer will only be used to fill the cooing system. The blowdown from the cooling system should be minimal.
In the cooling loop, you should think about using a cartridge filter to control the crud. You will also need a UV system to control organics.
RE: Demin Water System
Alright, I have checked with the suppliers and manufacturers and they did say cooling channles are made from copper... and they said should be ok running DI water through...
I am having conflicting information, thought DI eats up copper, so should I size a much bigger resin bed to take care of that? Please advise.
Thanks to you all!!!
RE: Demin Water System
Suggest that you get a complete water analysis.
As long as you have decent water quality, you should be able to operate without a demineralizer. You probably should consider a biocide as well as corrosion inhibitor as Kenvlach suggests.
RE: Demin Water System
Several suppliers:
http://ww
http://www.rtvanderbilt.com/spec_hi_3.htm
http://www.alken-murray.com/826pib.htm
Google on triazole corrosion inhibitor for more.
Re biocide: I've used a ACTICIDE® product containing octylisothiazolinone from supplier below, but it was for an open system w/o triazole (an organometallic dye solution), so others may have better suggestions:
http:
RE: Demin Water System
1.- DI water is not aproppiate for a chiller (use nitrite 500-700 ppm)
2.- If DI water touch a cooper material (is admiralty?), use azoles (2-3 ppm).
3.- considering a close loop system, < 130 GPM might you reposition water (less than 1%).
4.- TDS in recirculation water less than 30 ppm. (max conditions for welder system.
RE: Demin Water System
RE: Demin Water System
I have worked on a couple of fairly old and very high power electronic systems which used oil as a primary coolant running to a secondary heat exchanger with closed loop cooling water to an external fin-fan cooler. This eliminated the problem of maintaining isolation while ensuring there was no corrosion problem. Some processes would not tolerate the risk of contamination from a oil-cooled system. Is this a semiconductor application by any chance?
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