Final answer:
Natural draft cooling towers are subdivided into chimney towers and atmospheric towers, with chimney towers using a tall structure for upward air flow and atmospheric towers relying on ambient wind for cooling.
Step-by-step explanation:
Natural draft cooling towers are not subdivided into forced draft towers and induced draft towers. The correct answer here would be chimney towers and atmospheric towers. These cooling towers are essential components in industrial and power generation facilities. They rely on the natural convection of air to cool water. Chimney towers utilize a tall structure to create an upward flow of air, taking advantage of the fact that hot air rises. On the other hand, atmospheric cooling towers depend on the ambient wind and conditions to move air through the system for water cooling.
Cooling towers are integral to power plants, such as nuclear power stations and coal-fired power stations, as they help in dissipating the waste heat (Qc) to the environment. Particularly, the hyperbolic shape of large cooling towers is designed to facilitate the movement of air and enhance the evaporation and cooling process. Evaporation within cooling towers is an extremely efficient method of heat removal, often more so than direct heat transfer to air.