New Engineered-Plastic Cooling Tower Withstands Corrosion, High Humidity

May 1, 2011
Replaces L.A. building's old injector cooling towers

Built in 1982, the 16-story, 500,000-sq-ft office complex at 5777 W. Century Blvd. in Los Angeles is exposed to the corrosive effects of industrial effluents, jet fuels from nearby Los Angeles International Airport, and the salty Pacific air. Those effects, along with the prevailing high humidity, were weakening the building's injector cooling towers.

"This was a conventional system design back in the 1980s," Pat McGuire, sales manager for Centrifugal Technologies Inc. of Azusa, Calif., a longtime air-conditioning specialist, explained, "but over time, the injectors can corrode and clog, causing performance and maintenance problems."

McGuire worked with owner L.A.T. Investment Corp. on a new tower design and specifications.

"We felt that a newer type of cooling tower designed with a shell of engineered plastic would be more efficient and less maintenance-intensive for the application than simply replacing the old injector system with a new one," McGuire said.

McGuire recommended a single 500-ton TM Series cooling tower from Delta Cooling Towers.

"The double-wall plastic shell is impervious to UV light, pH, or corrosives," McGuire said, "so it's very low in maintenance. The tower operates well in high humidity. The shell has a 15-year warranty, which is unique in the cooling-tower industry. Also, I think it's got strong price advantages."

The high-efficiency TM Series features an induced-draft, counterflow design that is modular and capable of providing 250 to more than 2,000 cooling tons.

Running off of a variable-speed drive, the cooling-tower fan runs slower, consumes less energy, and creates less wear and tear on the motors. In office-building applications, the variable-speed fan gradually starts in the morning, as the weather warms, typically running at 30 percent until it shuts off in the evening.

Still, there was the matter of convincing building management and ownership that switching to new cooling-tower technology was the thing to do.

"The main factor that convinced us that we should go with the engineered-plastic cooling tower was the avoidance of unhappy tenants," Barron Lowery, the building's chief engineer, said. "Plus, we learned 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 the tower for quite a bit longer."

Lowery said that because of the new tower's higher efficiency, the need to engage the backup cooling system during peak-demand periods would be avoided.

"That would save us money and save on energy consumption," Lowery said, "so it was the green thing to do, and we decided to go with it."

A few weeks after installation, a record-breaking heat wave hit the Los Angeles basin, sending temperatures spiraling upward to 116°F—well above the normal late-September highs of the mid-70s.

"It performed very well," Lowery said of the engineered-plastic cooling tower. "In fact, I would say it exceeded everyone's expectations. And the tenants all stayed perfectly comfortable."

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