From: Kent.Martens@ct.spx.com
Sent: Wednesday, January 27, 2010 4:22 PM
To: Sunda, John B.

John, 

During our phone conversation, you asked about the cost impact of sound attenuation on cooling towers. 

As you suggested, I ran a selection to cool 150,000 gpm, with a 15 deg Range, 10 deg Approach to a 78 wet-bulb temperature. The baseline tower is 10 cells, about 48' x 486' in plan area with one 200 horsepower fan motor per cell.  The overall tower SPL (considering sound from both the mechanical equipment/fan exit, and the air inlet is 60 dBA at 500'. 

You mentioned a target of 50 dBA at 500'.  There are many ways to reduce sound, which include reducing fan speed, low noise fans, barrier walls, inlet and outlet attenuation and water splash attenuation.  For this example, in order to meet the target, I reduced the fan speed (which requires a physically larger tower), added fan deck and perimeter barrier walls, and splash attenuation.  The resulting selection is a 10 cell tower, 54' x 546' in plan area, with 125 horsepower fan motors.  The total estimated cost of the larger tower, along with the additional sound features is about 60% higher than the baseline tower. 

For lower sound levels, inlet and possibly outlet attenuation packages would be involved, probably driving the cost to more than 2x a standard tower. 

Please let me know if you have any further questions on this topic. 

I am doing a global search to determine if we have any plume-abated towers on seawater, or brackish water, and will let you know when I get some responses. 



Kent A. Martens, P. E.
Chief Technical Advisor - Evaporative Cooling
SPX Cooling Technologies
7401 W 129 Street
Overland Park, KS 66213 USA
Tel:      913/664-7501
Fax:     913/693-9522
Cell:     913/302-7234
kent.martens@spx.com


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