Issue link: https://cp.revolio.com/i/394834
12 | THE DATA CENTER JOURNAL www.datacenterjournal.com tower. Data center operators, however, should also note that refrigerant-man- agement issues can restrict evaporative- condenser size and/or placement owing to EPA regulations. MaIntaInIng a CoolIng tower Regardless of the type of cooling tower data center operators choose, they must be prepared to engage in regular and sustained maintenance because of the amount of water the towers use and the evaporation that takes place. e good news is that well-maintained cooling towers have a very long life expectancy— roughly 30 years. To ensure this lifecycle, data center operators will want to perform regular checks that focus on a few different potential culprits: Corrosion Fighting corrosion actually begins with the very development of the cooling tower. For corrosion (reduction-oxidation reaction) to take place, three elements are required: a conductor (metal), an elec- trolyte (water) and an oxidizer (oxygen). erefore, towers must be made of materi- als, such as stainless steel and PVC, that are made to resist corrosion. Building on this initial foundation increases a tower's sustainability and lifecycle. Scaling Water scaling occurs with the buildup of high levels of minerals, such as calcium deposits. Le untreated, scaling can greatly reduce the efficiency of cooling towers. Biological growth Algae, bacteria and fungi are other factors that can greatly reduce cooling- tower efficiency. Algae, for example, can form in large clumps that can plug pumps and screens and seriously inhibit heat flow. Bacteria can also grow anywhere in towers and heavily restrict water flow. Treating each of these ailments is fairly simple, but must be done consistently through the use of chemicals or other means. ese chemicals or other processes treat the water and attack any algae or bacteria that may form in the towers. To fight corrosion, acidity in the towers must be chemically neutralized. "Bleeding" can also be instrumen- tal in reducing the amount of scale and buildup that occurs in cooling towers. Bleeding involves regularly and inten- tionally discharging portions of water to maintain overall water quality. Although bleeding helps eliminate the accumula- tion of unwanted solids, it's important to replace any bled-off water with additional makeup water. e last aspect of cooling towers that should be regularly maintained is not chemical, but mechanical: fans. While they're built to last, some may eventually suffer from excessive vibration. is prob- lem can be a signal that something is faulty with a fan's gearbox or belt drive, or the fan itself. Typical causes include rotor bar or bearing defects, output-sha misalignment and more. ese problems can ultimately lead to complete failure, costing the data center significant time and money. Just like the water itself, fans should be checked regularly. is process can be done through monitoring their speed, which should be somewhere between 90 and 300 revolutions per minute, as well as by collecting and analyzing vibration data. is information can be gleaned from fans' motors, gearboxes, bearings and shas. Vibration issues should be addressed im- mediately to save headaches later. Although cooling towers are high- maintenance fixtures, they're not high- failure ones. at's due to their simplicity: water flows through from top to bottom via gravity aer being pumped to the top; air is forced through creating an air-water interface via a fan; the water's temperature will drop and the air's total heat content will climb; and the cycle repeats. But a certain degree of familiarity—and a big commitment to proper maintenance—is required to keep cooling towers flowing. With this knowledge, data center operators can ensure that their cooling towers will keep their operations running soundly and efficiently for a long time to come. n about the author: Robert Rosenberger is Vice President Data Center Operations, DuPont Fabros Technology