By Ed Sullivan
On what would normally have been a mild autumn day, Sept.27, Southern California was blasted by a record-breaking heat wave withtemperatures spiraling upwards to 116 degrees in the Los Angeles basin. Theheat was far above the normal highs, which would typically be in the mid-70s.
Naturally, the fierce heat combined with high humidity wouldbe a considerable challenge to maintaining the air conditioning in buildings ofall types, but particularly in office buildings, where tenants can beparticularly sensitive to uncomfortable temperatures. Happily, for the tenantsof an LAX Airport Center office building, the cooling tower that works in conjunctionwith the building's HVAC chillers had just been replaced. So, rather thanhaving to endure the sweltering heat, the tenants remained cool and comfortablein their offices.
"This was a very fortunate situation," says PatMcGuire, sales manager of Centrifugal Technologies, Inc. (Azusa, CA), alongtime air conditioning specialist who worked with L.A.T. InvestmentCorporation, the owner of 5777 West Century Boulevard, on the new tower designand specifications
A 16-story, 500,000-sq. ft. structure built in 1982, theoffice complex was originally equipped with injector cooling towers.
"This was a conventional system design back in the1980s," McGuire explains, "but over time the injectors can corrodeand clog, causing performance and maintenance problems."
As a mechanical contracting HVAC specialist, McGuire, ofCentrifugal Technologies, often evaluates newer cooling tower designs for bothnew and replacement installations.
"We felt that a newer type of cooling tower, designedwith a shell of engineered plastic, would be more efficient and lessmaintenance-intensive for the application than simply replacing the oldinjector system with a new one," McGuire says.
The engineered plastic cooling tower, innovated by DeltaCooling Towers (Rockaway, NJ), has been used in industrial and commercialapplications of many types because of its inherent resistance to corrosives aswell as high-efficiency features.
Because the 5777 West Century Boulevard building was locatednear Los Angeles International Airport, it was exposed to the corrosive effectsof industrial effluents, jet fuels and the nearby Pacific salt air. Thosecorrosive effects as well as prevailing high humidity no doubt werecontributing to the increasingly waning performance of the building's oldinjector cooling tower system. McGuire was convinced that the Delta plasticmodel would be best for this application.
"I like the Delta design," he says. "Thedouble-wall plastic shell is impervious to UV light, pH or corrosives, so it'svery low in maintenance. The tower operates well in high humidity. The shellhas a 15-year warranty, which is unique in the cooling tower industry. Also, Ithink it's got strong price advantages."
The model that McGuire recommended was a single, 500-tonDelta TM series cooling tower to replace the old injector tower. Thehigh-efficiency TM Series is an induced draft, counter flow design that ismodular, and capable of providing from 250 to over 2,000 cooling tons.
The cooling tower fan runs off a variable-speed drive, sothe fan runs slower, consumes less energy and creates less wear and tear on themotors. In office building applications, the variable-speed fan graduallystarts in the morning as the weather warms, typically running at 30 percentuntil it shuts off in the evening.
Still, there was the matter of convincing buildingmanagement and ownership that switching to a new cooling tower technology wasthe right thing to do.
"Centrifugal Technologies had serviced our coolingtowers and chillers for about 20 years, so we had a lot of faith that Pat'srecommendation was solid," says Barron Lowery, the building's ChiefEngineer. "The main factor that convinced us that we should go with theengineered plastic cooling tower was the avoidance of unhappy tenants. Plus, welearned that if we replaced the old cooling towers with the newer technology,we would have lower operational costs and could avoid the need to replace thetower for quite a bit longer."
Lowery says that because the new Delta tower promised higherefficiency, cooling would be greatly improved. Therefore he would avoid theneed to engage the backup system during peak demand periods in the middle ofthe day.
"That would save us money and save on energyconsumption. So, it was the green thing to do, and we decided to go withit," he says.
And a few weeks after installation, when theuncharacteristic heat wave hit the Los Angeles basin, the new cooling tower wasput to an extreme test.
"Itperformed very well," Lowery says. "In fact, I would say it exceededeveryone's expectations. And the tenants all stayed perfectlycomfortable."
EdSullivan is a technology writer based in Hermosa Beach, CA.
