If the purpose of cooling towers at nuclear power plants is simply to cool water, why are they towers? Wouldn’t the most efficient way to cool water be to spread it out in pools or ponds, so there would be the maximum of surface area?
Actually pools are the least effective way, they have the least surface area. The most effective way (that I can think of off the top of my head) is a radiator, or similar device with cooling fins or heat sinks.
That’s the reason that “car pools” have been so ineffective! 
[sup]They should have pushed for people to get into car radiators."[/sup]
The cooling towers I’ve worked on were air conditioning towers’ The hot water from the cooling system was pumped to the top of the tower and allowed to cascade over wooden ,“I’ll call them” ,slats. Sort of like a waterfall. Air was blown from below which cooled the water which again entered the cooling system. The heat entered the atmosphere.
Pretty efficent and simple really.
Through evaporative cooling the temperature can be made to drop below the outside temperature. This can be done many times and relatively quick.
I’m not sure about cooling ponds but I would guess once the water in the pond gets warm it would be difficult to cool .
The strong Hyperboloid shape of power plant cooling towers presents a great deal of surface area to moving air.
The shape of cooling towers and the particualr way the ducting and airflow is set up also allows them to cool effectively without needing fans. The air inside the tower absorbs heat from the cooling water, rising, and more air is sucked in through openings at the bottom to replace it. All passively, the only power needed is for the cooling water pumps.
The reason towers are used is to eliminate the need for fans. In order to force air through a tower you need a higher pressure at the inlet than at the exit. Since atmospheric air is less dense at higher elevations, a tall tower can produce a pressure differential great enough to eliminate the need for fans, thereby increasing the overall efficiency of the power plant.
The reason for the hyperbolic shape is mainly due to structural considerations. The hyperbolic profile has a superior strength-to-weight ratio and offers a greater resistance to wind loadings.