By Brian Kraemer
Published in the September 2005 issue of Today’s Facility Manager
Anyone who has ever walked into an office building during the dog days of summer to find out that the air conditioning system doesn’t work knows how hard it can be to accomplish anything. It’s taken for granted that even though it’s scorching outside, the office will be pleasantly cool. Of course, the average employee doesn’t realize how many different systems and components have to be in good working condition to lower the temperature to a blissful 68°F.
A facility manager, on the other hand, makes a living keeping the air conditioning unit and other building necessities operating smoothly. In particular, the cooling tower plays a pivotal role in employee happiness; if it isn’t functioning properly, the air conditioning isn’t working, and if the air conditioning isn’t working, you better believe a facility manager is going to be inundated with phone calls, pages, and smoke signals letting him or her know.
Like any technology, cooling towers have advanced over the years. From a humble, organic beginning in wood, sheet metal has become the predominate palette for cooling towers, which is a logical advancement. Unfortunately, metal towers, like wood before, have their limitations.
“Obviously sheet metal is going to rust,” says John Flaherty, president of Rockaway, NJ-based Delta Cooling Towers, Inc. The amount of water that is run through a tower on a daily basis will take its toll on the material, just like weathering would on any other metallic object.
“In order to prevent rusting, the metal towers are coated with a galvanizing, which is a zinc coating that doesn’t stop corrosion; it just slows it down,” Flaherty explains. “Eventually, the bare metal is going to be exposed, and that will corrode.” So now chemicals get added to the equation, making the life of a facility manager more difficult.
“It’s like a swimming pool in these towers. The water has to be maintained or else algae will accumulate. But the chemicals that prevent the algae attack the metals and cause premature corrosion,” says Flaherty.
But like their wooden predecessors before, sheet metal towers will eventually be replaced with something more reliable. In this case, it’s plastic.
“Like a lot of outdoor equipment, plastics are making inroads. Cooling towers, in particular, have only recently become a more viable option for a large industrial, commercial, or health care applications,” says Flaherty.
That is not to say that plastic cooling towers haven’t existed before. But they have been smaller and intended to be used on buildings with less square footage and have a lower cooling load that needs to be accommodated.
Because of advancements in molding technology, the path is clear for plastics to become a major player in the cooling tower universe. “We can mold pieces as large as 20′ long and very wide,” says Flaherty. Towers of this size should be big enough to handle any load that a building is going to throw at it.
The real advantages of plastic towers are actualized in two ways. First, the plastic isn’t going to corrode. This allows a facility manager to use all the necessary chemicals in the tower without having to worry about how many days are left before a giant hole appears on the side.
“We use a high density polyethylene for the specific reason that it isn’t going to corrode and break down through regular use,” Flaherty continues. “The plastic is formed with large molding equipment. We melt plastic resin over a mold to form a skin. Then, they pop the mold apart and get a piece which will make up the entire casing of the tower.”
Manufacturing after the casing comes out of molding includes incorporating heat-transfer media inside the casing, plumbing the water distribution system, and the mechanical fan motor assembly which draws air through the unit.
Installation is so easy it’s criminal. For example, in a large application, the sump and the main housing are shipped to the building, and the main housing is fit into tongue and groove fashioned sump posts; water and electricity are hooked up to the cooling tower, and it is fully operational.
“Once the tower is put together, a facility manager can be sure the structural elements will remain fit—the plastic won’t wear out or allow for leaks to form,” Flaherty explains.
This sense of security alleviates the other looming issue with cooling towers: downtime. If the cooling tower goes down, the entire building will usually shut down as well, which can result in lost money.
By the same token, because installation is not complex and doesn’t require on site construction, the install or retrofit can be arranged in an evening or over a weekend when the building is not in use. This allows employees to continue coming to work and avoids interruptions in the work place.
Plastics are emerging as the next trend in cooling tower technology because of their plug and play capabilities. A facility manager can install the tower in an evening or in one day over the weekend, hook it up to the HVAC system, put the proper chemicals in to treat the water, and not need to worry about waking up one day to find a hole in the side of the tower and, have the building shut down.
Information for this article was obtained from an interview with Flaherty and with information from the Delta Cooling Towers Web site. For more information, visit www.deltacooling.com.