# Thread: Questions regarding water cooled A/C and high water bills

1. Originally Posted by KickedGinger
Im using Comfort Aire spec. With 1700 tonnes of cooling when the water is @ 70F the units use 1.35 GPM/ per tonne.
1.35GPM x 1700 tonnes = 2295 GPM

You were right to correct me on the GPM. The units use 3 GPM @ and inlet temperature of 85F

However 2295 GPM is still a heck of alot of water.
Thanks again for your help.

Keep in mind this is a fairly large plant with 45 -50 units. Is it even possible to run the supply and return lines that far? I suppose I would just increase the size of the pumps?
Still not seeing the 1700.. I believe I am missing something... First off a "tonne" is an odd choice of unit of measure (used for burning of petroleum to generate power).

Here is a basic BTUH calculation equation.

BTUH= GPM x Delta T (F) x 500

There are 12,000 BTU's in one ton of refrigeration.

Let me know where I am going wrong.

Regardless, cooling towers would be the best option budget wise, fluid coolers would be the ultimate.

GT

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Originally Posted by GT Jets
Still not seeing the 1700.. I believe I am missing something... First off a "tonne" is an odd choice of unit of measure (used for burning of petroleum to generate power).

Here is a basic BTUH calculation equation.

BTUH= GPM x Delta T (F) x 500

There are 12,000 BTU's in one ton of refrigeration.

Let me know where I am going wrong.

Regardless, cooling towers would be the best option budget wise, fluid coolers would be the ultimate.

GT

Yes youre right!! how embarrassing! I will total all units and re-check the tonnage. I think I mixed up jobs!
assuming I am wrong (which I think I am) cooling tower seems the way to go?

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cooling towers are quite massive by default, if your plant have space issues, calculations should be done well in advance.

other than that, as someone mentioned, return on investment should be really on good side, knowing water bills are quite high anywhere.

distance is not an issue, you are designing water network and come to pumps you need. other than space, noise can be an issue in general, but for industrial plant that would likely not be a problem.

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