Water or liquid cooling is the most efficient cooling method and requires the smallest footprint when cold water is readily available. When used in power generation the steam/vapor that exits the turbine is condensed back into water and reused by means of a heat exchanger. Water cooling requires a water resource that is cold enough to bring steam, typically super-heated, to sub-cooled temperatures. If the water composition has a high concentration of solids (such as minerals) filtration may be required in order to reduce the amount of maintenance on the heat exchanger. If filtration is not economically viable, or the water temperature and flow are not suitable for heat extraction then Air Cooling or Hybrid Cooling may be used in place of water cooling.
From Open Energy Information