The steam and cooling water circuits

The steam-water cycle in the power plant is a closed system: water vaporizes in the boiler; the steam expands in the turbine and then condenses in the condenser to water, which is returned to the boiler by pumps. In addition, there is a cooling water circuit: in the condenser the exhaust steam from the turbine is routed past thousands of tubes; cooling water flows through these tubes and condenses the steam to water. The cooling water is warmed up in the process. Cooling water often used to be taken from a river and returned to the river warm. Today, the warming of rivers which this entails is avoided. Instead, the cooling water is cooled in a cooling tower: inside the tower the water cascades from a height of several meters into a collecting basin, the cooling tower pond, and as it falls is cooled by the ambient air, which rises in the cooling tower as if in a chimney. A part of the cooling water evaporates and is visible as the cooling tower plume; this loss is made up with fresh water. Afterwards the cooling water is pumped back to the condenser.