BAC cooling tower information 1

[russmech]

Does anyone have access to an old Baltimaore Air Coil (BAC) selection guide (book) for a VS series cooling tower? I'm trying to recommission a 1974 vintage VST cooling tower and have been unable to track down performance data for it. The factory (so I've been told) scanned their old catalogs, then discarded them; however, the scanned performance charts I've gotten from them are unreadable.

Thank you in advance if you could find performance information for a BAC VST-325A (or similar) cooling tower.

 

[KiwiMace]

Wow! were they SS and still in the box? I recently changed out 4500 rt worth of BAC towers after 7 years.

 

[russmech]

The two cooling towers are in Anchorage, Alaska where the cooling season is somewhat short (I state the obvious) so wear and tear is "below normal" for a cooling season. Also, they were spec'd with a really good anti-corrosion coating that has done well to protect them.

So, do you have any performance data for it?

Anybody else need to add to their good Karma pile and help me out here?

 

[lilliput1]

Also try to get the electronic copy of the file, convert it to TIFF and try to sharpen it with Photoshop.

 

[daly1]

assuming you get this information you need to also take a suspicious eye at the data. Prior to CTI being formed all the cooling tower manufacturers cheated--to varying degrees. As someone that designed hundreds of central utility plants I saw this cheating could amount from 20% to as high as 50% of the listed performance.

You might want to think about hiring a CTI certified company to generate your own, onsite performance curves.

In terms of the coating, check on the inside of the CW basin if you haven't already. BAC for years used the equivalent of a G-90 HMG coating where others used G-235 HDG coating. BAC made up for this by selling a polymer coating called Baltibond--sold as "as good as stainless steel". I have never seen a baltibond (grey looking coating) survive the warranty period. However, they always seem to look good on the outside.

 

[russmech]

Thanks daly1.

I did find charts for these towers from an old friend in the lower 48 who had a catalog sitting on a shelf in a back warehouse. Fortunately for me:

1) These towers will be paralleled and under utilized, so I should have plenty of capacity for the chiller they'll be serving.

2) They are located in Anchorage, AK where 40 years of age equates to less than 10 years of service. The Baltibond coating is still in good shape; I did not see any rust in the pans.

I plan to replace all the internal piping, spray headers, media, spray eliminators, water valve, etc (these towers were decommissioned about 8 years ago without being cleaned first). Any other advise you can give me? Cooling towers are not a large part of the HVAC industry here.

 

[daly1]

I'm not a fan of the forced draft style towers mainly due to HP considerations and basin leaks. However, the lone applications where they shine over induced draft towers is ducted units and cold environments (both of which we only see in very cold environments like yours).

The spray headers are fairly straight forward and the nozzles BAC sells are decent. The fill they use is adequate but their drift eliminators are poor. You might want to consider what are called cellular drift eliminators (DE's)--as they have lower pressure drop and are much more efficient wringing water out of the airstream. Many of the VT's had the DE's mounted on top of the cells and made from a heavy galavanized steel. Check to make sure they are still in good shape.

Big thing to evaluate is the bearings and drive shaft and condition of the fans. The longer cells have a motor at one end and as many as three bearings supporting the shaft/fans. Changing the bearings is a flat pain in the butt--so check these before you fire it up. I think BAC later offered a split shaft design to make these kind of repairs easier--so check into this. Make sure the fans haven't seized and are also in good shape.

Something to also consider is IF you change the fill, PVC distribution system, DE's, and shaft/bearing--then you might want to look at how much a new tower would cost.

 

[heatreject]

When you want to calculate the tonnage of the towers, don't forget that the wetbulb of Anchorage Alaska is about 60 degrees. Baltimore Aircoil will supply all parts and retrofit kits for these older towers. If you need more info let me know, we have all the old catalogs and part listings here.