Unlike natural draft cooling towers that use natural methods, mechanical draft cooling towers use fans or other mechanical devices to circulate air in the tower. The fans used in mechanical draft cooling towers are propeller fans and centrifugal fans. Natural ventilation and evaporative cooling towers are not as efficient as mechanical draft towers; they can also be conveniently placed in buildings with appropriate exhaust systems. The operation of mechanical draft tower requires a certain amount of power consumption, so its cost is higher than that of natural ventilation cooling tower. The types of mechanical draft cooling towers are subdivided as follows:
The counter flow cooling tower cools the air by moving the air upwards and the water flowing downwards. Compared with cross flow cooling towers, counter flow cooling towers have a smaller footprint, and in the long run, they can even save energy.
The airflow in the cross flow cooling tower is horizontal, and the hot water flows downward from the distribution basin. Cross flow cooling towers are more susceptible to icing. They may be as tall as counter flow cooling towers, but they are less efficient than counter flow cooling towers.
Hyperbolic cooling towers require far fewer resources, but they are well built. Although operating with fewer resources, they can effectively manage large-scale tasks in large chemical plants or power plants. These cooling tower systems have stack stacking technology, through which they can allow colder outside air to push moist, warmer air into the tower.