Abstract: The invention concerns a method of preventing or eliminating fog over an area of land, for example an aircraft runway, a motorway carriageway, part of a road or some other area. The method calls for water to be sprayed through several nozzles into a given body of air over the area to form finely divided water droplets. The invention also concerns a system for carrying out this method.

Abstract: The invention relates to a device for the recovery of a processed liquid in the form of a condensate from a liquid to be processed by evaporation and condensation, having at least one first flow region which is provided in a working space for the development of a first sheetlike flow of the liquid to be processed and at least one condensing surface, adjacent to the first flow region and cooler in temperature than the first flow, for liquid evaporated at the first flow region.The invention is characterized in that a second flow region is adjacent to the at least one first flow region in the common working space for the development of a sheetlike second flow, and in that the condensing surface is formed of the surface of the liquid of the at least one second flow region.