Keeping a cooling tower free of dangers such as bacteria and corrosion is best achieved through a regular, comprehensive maintenance program. Although recommendations for the frequency of certain actions tend to vary, a comprehensive program includes draining and cleaning, water treatment, mechanical and electrical component inspection, and winterizing.
Discussing the importance of regular cleaning, Todd Beard, regional operations director at Lee Company, noted towers should be drained and cleaned at least once a year.
“Sections of the tower that should be cleaned are the hot and cold water basins, fill, and nozzles,” he said, adding, “Nozzles, which are located in the hot water basin, sometimes get overlooked during cleaning. Maintaining the nozzles is a very important step in the cleaning process. Properly functioning nozzles ensure water will be delivered uniformly over the fill. This is important in order to achieve maximum capacity from the tower.”
Drew Wettlaufer, vice president, building services and energy solutions, Marble Mechanical Service, Birmingham, Michigan, emphasized the importance of good water treatment.
“Without some kind of water treatment, bacteria can tend to form, which, in turn, could foul condenser tubes and reduce chiller efficiencies,” he said.
Mihir Kalyani, HVAC marketing engineer, Evapco Inc., also stressed this point, stating a systematic water treatment plan should be implemented from day one. “Makeup and recirculated quality must be checked on a regular basis, as often as weekly,” he said. “A systematic water treatment plan must be put in place to ensure prime water quality.”
Without a plan like this in effect, Kalyani warned, “Scale, corrosion, and bacteria growth can quickly deteriorate water quality.”
Beard and Chris Walton, assistant manager, marketing communications, Baltimore Aircoil Co., noted some of the greatest risks stem from potential airborne impurities and biological contamination. “These threats, such as Legionella, should be controlled through the use of biocides,” Walton said. “And, such treatment should be initiated at startup and continued regularly.”
Walton also pointed to ASHRAE Guideline 12-2000, “Minimizing the Risk of Legionellosis Associated with Building Water Systems,” as an excellent resource on this topic.
The mechanical and electrical components of cooling towers also require maintenance. Walton noted cooling tower fans are typically driven by belt- or gear-driven systems.
“Both require routine maintenance to ensure reliable, trouble-free performance,” he said.
Beard added, “Regular inspection of these components cannot be overlooked when it comes to the overall maintenance of a tower.”
And, finally, Beard said, depending on the region and application of the cooling tower, it should be drained and winterized for the non-cooling season.
Benefits Can’t Be Ignored
Despite the tendency to ignore or overlook cooling towers, the benefits of an all-encompassing maintenance program cannot be overstated.
Summing up the overall importance of cooling tower maintenance, Beard said, “In the end, a poorly maintained tower is a sure and proven way to increase spending and decrease life expectancy of some of your most valuable assets.”
Source: ACHR News