What are Cooling towers and what are their types?

Question

What are Cooling towers and what are their types?

Answer 1

The first answer is absolutely correct. I had once answered a similar question, my answer to which is below. In addition to the link ½∞ Is still Forever has provided, I hope my answer will be of useful to you too.

There are three types of them

1) Natural draft

2) Forced draft

3) Induced draft

Although cooling towers can be used to bring the temperature of water down to the wet bulb temperature (WBT) only, they are extremely popular in the chemical and power generation industries. Cooling towers work on the principle of evaporative cooling, where a part of the water is evaporated by the current of the air that it is in equilibrium with, which absorbs heat for vaporization from the water thus effectively reducing its temperature.

Natural draft is different from the other two in that no fan is employed to suck air inside the tower. Forced and Induced drafts employ a fan that increases the flow rate of air inside the cooling tower. Forced draft has a fan at the bottom which effectively throws up air into the tower. An induced draft cooling tower has a fan at the top which is used to suck air bottom to top. This causes higher turbulence between the air and water and hence result in a higher efficiency although the operating costs are relatively higher than the forced draft. One more problem is the corrosion of the fan blades due to the high humidity it is exposed to. Forced draft fans are not exposed to water. Natural draft towers are used when the temperature gradient is not very high and are cheaper because no fans are involved.