At a major automotive assembly facility, cottonwood seed, insects, and other debris were getting drawn into the cooling tower, building up in the fill material and water basin, and circulating through — and clogging — the heat exchanger, resulting in hundreds of thousands of dollars in lost productivity and maintenance expenses.

In most regions of North America, cottonwood seed is a major contributor to cooling-equipment fouling. This naturally occurring airborne contaminant (generated by the poplar tree) usually affects operations from May through early August. As a result, HVAC maintenance engineers typically have to clean equipment frequently or risk failure during this period. During late summer, insects, paper, construction debris, birds, and more seem to find their way into cooling equipment. The final seasonal assault comes during fall, when trees drop their leaves, scattering them to the wind and, eventually, condenser coils and cooling towers.


The facility's chief engineer elected to install air-intake filters from Air Solution Co. The filters, which mount to the outside of the air-intake opening of the cooling tower, include a galvanized storage container and a pulley hoisting mechanism that allows them to be raised and lowered as needed. The filters were designed to stop cottonwood seed, insects, leaves, paper, construction debris, and other airborne matter that can get drawn into a system.

Unlike commercially available mesh-screen products (window screen, bug screen, shade screen) and conventional filters, which can damage equipment by restricting airflow when placed over intake openings, air-intake filters are engineered to be nearly invisible to airflow. Because they mount to the outside of equipment, they stop airborne debris at its point of entry, where it can be seen easily and removed quickly. Further, they do not require removal for cleaning. Even rain will clean them.

“Air-intake filters have dramatically reduced the maintenance requirements for our cooling towers,” the chief engineer said. “Furthermore, the filters are very easy to clean. Now, all we have to do is clean the filters with a broom or brush. We've put an end to having to shut down the tower to clean it. …

“Another benefit of using the air-intake filters is that it has improved the effectiveness of our chemical-treatment program because they remove the larger airborne debris that was the cause of our problem in the first place, allowing the chemical dosing to work on the smaller particulates,” the chief engineer continued. “And because the filters remove organic debris that is a nutrient source for bacteria, it helps us to prevent proliferation of bacteria in the water, including Legionella.”

The filters “have truly benefited our operation at this facility,” the chief engineer concluded. “For us, the cost of not having to shut down the (robotic) welding line and reallocate our maintenance resources more than justifies the investment we made in the air-intake filters.”

Information and photograph courtesy of Air Solution Co.
Circle 103