There are two main types of cooling towers: counter-flow and cross-flow. In a counter-flow cooling tower, air travels upward through the fill or tube bundles, opposite to the downward motion of the water. In a cross-flow cooling tower, air moves horizontally through the fill as the water moves downward. Since the counter-flow tower is a preferred technology and since Yolyapı specializes on it we will explore it in more detail.
A counter-flow cooling tower is an enclosed structure with internal means to distribute the warm water fed to it over a labyrinth-like packing or "fill." The fill provides a vastly expanded air-water interface for heating of the air and evaporation to take place. The water is cooled as it descends through the fill by gravity while in direct contact with air that passes over it. Mechanical-draft cooling towers rely on power-driven fans to draw or force the air through the tower. The cooled water is then collected in a cold water basin below the fill from which it is pumped back through the process to absorb more heat. The heated and moisture laden air leaving the fill is discharged to the atmosphere.