Within the process a supercharged first combustion chamber is followed by: a first turbine, a second combustion chamber, a second turbine, and a preheating heat exchanger. Primary bleed water vapor coming from the secondary process, or a mixture of the bleed water vapor and air coming from the supercharger, are preheated. Secondary-process feed water is vaporized in a waste heat boiler. The combustion gases are expanded in the second turbine to a pressure 0.5 bar lower than that of the surrounding atmospheric pressure. The remaining combustion gases are compressed by a combustion-gas supercharger to the surrounding atmospheric pressure.