	316B PHASE III RULE

 TELEPHONE LOG

Name of Caller: 	John Sunda, SAIC

Date: 			February 12, 2009

Company Name: 	Blue Stream Services

Street Address:		

City/State/ZIP:	New Iberia, LA

Person Contacted:	Richard Brister 

Title:			Cooling Tower Specialist		

Telephone #:		504-400-0093

E-Mail: 		rabrister@bellsouth.net                                       
                                                                        
                  

Called to inquire about modular tower design and why power use was
higher

He said the 3000 ton units use more fan power because of their compact
design. This design allows for more flow and cooling capacity per unit
that other designs and especially compared to large permanent towers.
Not only does this save on space but also costs since each unit will
have costs such as shipping, installation, rental, etc that are more
sensitive to the number of units than the unit size. Thus, more cooling
per unit equals less costs.  Typically, each unit uses 400 amps and if
single unit pumps are used they require 400 amps as well. 

I asked about approach values and he said a typical design spec for the
3000 ton unit would be:

Hot water:	95oF

Cold Water:	85oF

Wet Bulb:	78oF

Thus, in this instance the approach would be 7oF and in general, the
approach will range between 7 and 10oF. Of course this would vary with
flow, range, wet bulb temperature, and type of fill used.

They use a Brentwood film type fill and that the fill selected will be
determined by the quality of the water. Typical fill might be the
Brentwood CF1900 Cross Fluted Film Fill Media.  This is rated on the
Brentwood website as suitable for “average to good” water which is
defined as:

Use CF-1200 or CF-1900 when:

• TSS < 25 PPM (<100 PPM where bacterial activity is very low)

• Make-up from uncontaminated sources

• Good biological & scale control

• Low cycles of concentration

• Minimal airborne dust

• No oils or grease

If the water quality is poor and contains solids that might tend to clog
fill then a fill with larger openings is selected.  Such fill will be
less efficient (less surface area and less air water contact) and may
reduce efficiency by 6 to 10%. If all else is equal this will increase
the approach.

I asked whether he knew of any situations where a cooling tower produced
cooler water than the surface source water.  He said they were working
on one project (deal not yet sealed) in Texas where the lake water
reaches 95oF in the summer. Operating in a helper tower mode, they
figure that they will be able to return cooling water back to the lake
at a temperature lower than 95 oF and thus actually reduce the lake
temperature. He noted that one of their selling points is that they
actually increase DO in the discharge whereas once-through tends to do
the opposite.  I suggested they look at using a recirculating mode.  He
said they usually use a design wet bulb temperature of around 78 oF but
that it might be higher in areas along the Gulf like in Louisiana where
it might be 80-81 oF. Even then, these design wet bulb values are
present only a fraction of the time. 

