Dry Cooling Towers:
In this type of cooling tower, the working fluid is channelled through tubes which collects the ambient heat and then this heat is exchanged with atmosphere using air as a medium. No liquid or water is hence used for cooling in this type of setup
Wet Cooling towers:
It is also known as open circuit cooling towers. The working principle of wet cooling towers is evaporative cooling and in this case the working fluid or the fluid used for heat exchange and the fluid that is actually evaporating is the same i.e. water.
Also known as closed circuit cooling towers, these devices are actually hybrid in nature and combine the best of both dry and wet cooling systems. Here the working fluid or the heat exchange fluid is encased in a tubing system and never comes in contact with the open atmosphere. The tubing or the heated tubing is then subjected to a stream of water which in turns exchanges the heat.