Cooling water moves through the heat exchanger where it is physically isolated from the path of the medium to be cooled, so as not to diminish its quality. At the heat exchanger, the ciruclating water flows through a bundle of thin wall condenser tubes or plates, while spent steam from the turbine exhaust passes downward, around abd through the tube bundle, exchanging its latent heat with the cooling water inside the tubes. The resulting condensate collects in the hot well beneath the tube bundle.