cooling tower evaporation rates

[y1a1n1k1s1]

I'm trying to figure out the amount of gallons of evaporation from our cooling towers (our meter is broken). The conductivity of the water is 1000 to 1200 and the load is 650 tons. We have Marley forced induction cooling towers (4 500 ton cells in use)(don't ask why). I have been told that 100 gallons/per hour/per ton is a good rule of thumb. Any comments or suggestions would be appreciated.

 

[imok2]

The evaporation rate can be evaluated by any one of the following methods

1. The evaporation rate is = to 2 GPM per million BTUHof heat rejection or

2. The evaporation rate is = to 3 GPM per 100 tons of refrigeration or

3. The evaporation rate is = to Q(gpm)x R(*F) x ,oo1