Cooling towers in thermal power plant is basically used to cool the water coming from the condenser pipe .Cooling towers consist of a nozzle for spraying the hot water , an heat exchanger where there is a transfer of heat between the hot water and air.The water vapour formed vaporises upwards through the cooling tower . Larger water vapour particles are trapped back by the drift eliminator to the heat exchanger. Now the cooling water formed at the bottom of the cooling tower is circulated towards the condenser water entry pipe.                                                        Hope I'm not wrong.