The round hybrid cooling towers which Balcke-Durr GmbH is currently building for the 550-MW-IGCC-power-station of a refinery project on Sardinia have to meet particularly stringent requirements as seawater is used for cooling. The advantages are: avoidance of visible plume with minimal energy consumption, optimal plume exit velocity and discharge, greatest possible stability of the plume column, avoidance of interference and recirculation, high operating reliability of the cooling tower.