Any closed loop chilled water experts?

[David]

We have a 3000 gallon closed loop cooling water system (two 240 ton chillers) at work. I can't find any real "experts" on the system. I can find plenty of salesmen who want to sell us water treatment, but none who really seem to know what they're talking about.

Most of the water treatment systems are for open loop, cooling tower systems.

I have found some info on chemical treatment to add to the water and I'm leaning towards trying those although the original installer mentioned off the record that pure water was fine.

If we don't add chemicals to the water, I wonder how often we should change the water.

Thanks for any advice

[Joeaksa]

Have you ever gotten the water checked for what minerals and such are in it? That would be my first step.

[TerryH]

Not sure what you're asking, but don't you want water treatment? Maintaining a PH level, descaling, and hardness isn't too difficult on a closed system. Piece of cake compared to evaporative towers as there isn't nearly the amount of make-up water being added to the system. You can service this system yourself or choose not to service at all.

Usually rodding out the condensors/heat exchangers annually can be beneficial too.

[sammyg2]

We use GE/BETZ for our water conditioning and they do all the sampling and testing, but like you said that's an open coolling tower situation.

[red-beard]

I guess it first depends on what the rest of the materials are in the system. Fully demin water is corrosive, so usually you need an anti-corrosion additive. If the materials in the system contain cast iron, you'll be changing it more often than aluminum, copper or stainless.

What is the chilling application?

[David]

This is for the HVAC system on our 100,000 sq ft machine shop. It has two 240 ton chillers and 15 air handers. The water loop is about a 1000 feet. The majority of the piping is carbon steel.

As much as I hate GE, they do make good products so I was looking at the GE Corrshield, but I'll get the water chemistry checked first.

[Porsche_monkey]

We just added a anti-fungal / anti-bacterial agent a few times per year. Started with city water. It has been in there ten years now with the occasional top up.

[red-beard]

Originally Posted by 125shifter

This is for the HVAC system on our 100,000 sq ft machine shop. It has two 240 ton chillers and 15 air handers. The water loop is about a 1000 feet. The majority of the piping is carbon steel.

As much as I hate GE, they do make good products so I was looking at the GE Corrshield, but I'll get the water chemistry checked first.

Demin water, plus an anti-corrosion agent should work fine. Make sure you flush the system out before putting in the final demin/anti-corrosion agent. On the turbines and the recip engines, we'd heat the water and bang on the pipes (get shakers if you can), and circulate the water at the highest speed, to get dirt, weld slag, etc, out of the pipes. Use a "witch's hat", fine mesh cone filter over a steel cone frame. Keep pulling and cleaning the filter until it run cleans for 8 hours. THEN put in the final fluid. The point of the hat goes towards the source of the fluid.

This is what one looks like that is really-really-really dirty.







That is a combination of rust particles and cosmoline. It was in the water system.

[David]

The water (tap water) is still almost crystal clear after a year with no additives, but I'll get it sampled and report back

[billybek]

There are lots of suppliers for water treatment. Try to find one soon.
New systems are degreased with a scrubbing solution with several water changes afterward.
I would strongly recommend at least a good inhibitor from a reliable supplier that will give you a test kit with the purchase. Once a closed loop is set up it really needs very little attention.
What chillers were installed?

[David]

Originally Posted by billybek

What chillers were installed?

I'm not in my office so I don't have the model handy, but they're 239 ton Carrier units.