Drift removal is more than a function of simply putting a drift eliminator into a tower. Installation quality and workmanship are some of the largest factors that affect drift capture in a cooling tower. Even if you purchase and install the best eliminator that money can buy, if the air is able to bypass the eliminator, you will be allowing drift to escape.
Another factor that influences the potential for drift issues is the geometry of the cooling tower. For this article, the focus in on factory assembled (“package”) crossflow cooling towers. Unfortunately for some tower owners, even towers straight from the factory with brand new OEM fill can have drift issues. “How is this possible?” you may ask. One reason for this could be the result of the geometry of the cooling tower creating an imbalance in the airflow. Crossflow towers that are tall and narrow will concentrate the airflow into a smaller section close to the fan inlet versus towers that have larger plenums that can better equalize airflow. Computational Fluid Dynamic (CFD) analysis of some different tower geometries help to visualize this: