An air cooled condenser (ACC) is a direct dry cooling system where steam is condensed inside air-cooled finned tubes. The cool ambient air flow outside the finned tubes is what removes heat and defines the functionality of an ACC. In thermal power plants (T), the steam from the turbine exhaust flows into the ACC where condensation occurs. Then the condensate returns to the boiler (B) in a closed loop. Since the steam coming from the turbine is at a low pressure, the ACC works at a pressure close to a vacuum, and non-condensable gases (G) are removed continuously by an air evacuation unit.