The waste heat from a steam turbine is condensed and used to desalinate sea water at the same time. The waste steam from a turbine is fed to a condenser through which cold sea water passes. As the cold sea water condenses the waste steam, it is warmed. It is then introduced into a first chamber which includes a number of spray heads disposed over fill (packing) that acts as an evaporator. Any water not evaporated is collected in a sump at the bottom of the first chamber, and the evaporated vapor is passed upwardly under the influence of a fan and ultimately to a second chamber. The second chamber may either be stacked above the first chamber, or in side-by-side relationship with it. A condenser, such as a number of dimpled metal plates, or plastic membranes defining a closed loop, or another set of spray heads and fill, are provided in the second chamber. Air typically recirculates from the bottom of the second chamber back into the first chamber. The product (fresh) water is collected at the bottom of the second chamber, and may be cooled by cold sea water and a portion of it introduced as the condensing liquid in the second chamber.