Plastic cooling towers paired with chillers

optimize HVAC systems

With maintenance and energy costs going through the roof, building owners and operators are taking a long-term perspective on HVAC cost of ownership. This, in turn, has caused HVAC system OEMs and distributors to take a closer look at the pairing of chillers with higher efficiency cooling towers, and to rethink their inclination to recommend and use “traditional” metal-clad cooling towers.

“We are using engineered plastic cooling towers because they match up well with our chillers to create a highly reliable and efficient system,” said Roger Shull, equipment sales team leader at Damuth Trane in Chesapeake, Va. “Plastic cooling towers are a natural fit for us. They also enable us to offer a system that will minimize the usually high maintenance and replacement costs. And because they are selected together, we can maximize the energy efficiency and performance of the hvac system.”

Shull emphasized the need to match the chiller and cooling tower -- the two primary HVAC components -- to optimize system performance.

Just as plastics have overtaken metal for applications ranging from plumbing to aerospace, they are now eliminating the need for metal in cooling towers for a broad range of applications. Utilizing advanced resins and molding techniques, engineered plastic cooling towers are available today in larger sizes and modular configurations that make them ideal for even high-capacity applications (1,500-2,000 cooling tons) that traditionally depended on expensive field-constructed installations.

Standard metal cooling towers are lined with thin sheets of galvanized steel. These sheets usually have welded seams that can deteriorate over time, and require re-welding, patching or coating to prevent leakage. Cooling tower water requires conditioning, water treatment chemicals and high pH that attack the metal lining, essentially wearing it out in a few years’ short time.

Furthermore, although chillers are normally placed within the shelter of a building, cooling towers are located outside, where they are exposed to weather and such external elements as salt air, harsh industrial emissions and chemicals that are used to treat HVAC water. These corrosive elements spell trouble for cooling towers clad with galvanized sheet metal.

“Corrosion resistance is of utmost importance to our customers,” said Shull. “Delta offers a unique design, utilizing plastic components in the basin and fan construction. Our office complex is 10 miles inland from the Atlantic Ocean, yet our original galvanized steel cooling tower corroded and required replacement after only eight years of service. We replaced it with a Delta plastic cooling tower, with a 15-year warranty on its shell. The single-piece construction on the basin means no leaks, which is an advantage over the sheet metal-lined towers that are susceptible to leaks. The avoidance of leaks, corrosion and low maintenance are three important advantages of the Delta cooling tower.”

At the same time, Shull recognizes the importance of improving energy efficiency wherever possible in HVAC systems. Many cooling towers are turned on and off with great frequency. This fluctuation causes stress that can also accelerate corrosion, rust and leakage, as well as severely polluted cooling water.

In addition, the cost of electric power to drive cooling tower fans can add up. For reduced maintenance, Delta Cooling Towers has designed their towers to use direct-drive motors to power their fans.

“The design of the fan is inherently important,” adds Shull. “Low maintenance means lower cost of ownership. If there are no mechanical belt drives or gear boxes to wear out, that is definitely of benefit to a building owner because it will save on maintenance. To emphasize the fact, we offer all Delta Paragon, Premier and tm Series towers with a lifetime parts and labor warranty on the gearbox, pulleys and belts at no additional charge. We can do that because these components don’t exist like they do in a competitors tower. Things that don’t exist can’t break.”

By avoiding maintenance costs, Damuth Trane customers are on better financial footing, Shull said. Also, regarding the costs of steel, over the past couple of years prices have skyrocketed. For building owners who are concerned about initial purchase or retrofit price differences between plastic and metal-clad cooling towers, that cost difference has significantly narrowed.

Shull added that the warranty also tells an important story: Metal-lined cooling towers generally have a one-year warranty; the shell warranty of a Delta plastic cooling tower is 15 years.

For more information, contact Delta Cooling Towers at 800/buy-delta, e-mail sales@deltacooling.com or visit www.deltacooling.com.