Comments on: Welcome to BAC @ You!

By: HoweKool

HoweKool — Fri, 16 Apr 2010 15:41:07 +0000

Francisco,

There are some customers that use chemicals to remove white rust. However, they have to be very cautious since they use acid to remove the white rust. The issue is that the acid will remove the white rust as well as the galvanizing on the remaining parts of the unit. The best method is to mechanically remove the white rust and repassivate the Evaporative Condenser, which is discussed in the Common Section of the Operation and Maintenance Manuals found in the BAC Knowledge Center. If you still would like further information please contact your Local BAC Representative:

FES-Ohio, Inc.
Email: fes-ohio@baltimoreaircoil.com
Phone: 513-772-8566

Thanks again for the great question!

By: Francisco Flores

Francisco Flores — Fri, 16 Apr 2010 14:05:29 +0000

What is the best approach to clean an evaporative condenser galvanized tube bundle when white rust has already developed? Mechanicaly cleaning the outside tubes wouldn’t be too much of a problem, but the question is the inside which is where most of them are.

By: Dan Kelly

Dan Kelly — Wed, 24 Mar 2010 17:40:50 +0000

I agree with your comment to Tony Chuang’s question, that capacity can be either Air Side with a VFD on the tower fans or water side with varying the pump speed. Tony should check with each manufacturer to confirm the turndown possible given the configuration (counterflow vs. crossflow) and should understand that it’s absolutely critical to make sure the heat transfer media is properly wetted at the reduced water flow, if that’s the capacity control method he’s like to employ. Evaporation to dryness may cause excessive scale build up, which may lead to maintenance issues later in the life of the unit.

Tony, posting a message at 11:15pm last night – now that’s dedication!

By: HoweKool

HoweKool — Wed, 24 Mar 2010 12:18:53 +0000

Tony thanks for the post!
The capacity of a cooling tower needs to be controllable to accommodate the changes in thermal load. Modulating the airflow is the most common way of controlling the capacity. Variable speed drives, fan cycling, two speed motors and pony motors are means of regulating the airflow. Aside from air flow modulation, water flow modulation is another way of controlling the capacity of a cooling tower. However, reduction of flow below the recommended level may potentially create an uneven water distribution through the fill, causing scale build up, splash out/drift and icing. To successfully modulate the water flow while avoiding potential complications, dams may be installed in the hot water basin of crossflow cooling towers for a minimum flow of approximately 50%. For counterflow cooling towers, the minimum flow is limited by the nozzles used in the product which are based on the design flow.

By: Tony Chuang

Tony Chuang — Wed, 24 Mar 2010 03:15:23 +0000

In cooling tower application, what is the effect on performance caused by variable condenser water flow?
Is there any difference between counter-flow and cross-flow regarding the above issue?
Is there any flow limitation?
Thank you,