Abstract: A method for improving the total production of useful energy in an energy utilization system of a thermal power engine (1) that is liquid-cooled and is used for the production of thermal energy as well as mechanical energy. In the energy utilization system, thermal energy is taken from the coolant of the engine cooling system. At least a part of the coolant from the engine is led to a vaporization space (5) where, either by lowering the pressure or by increasing the amount of thermal energy within that space (5), a part of the coolant is transformed to vapor. The vapor is used within the energy utilization system for energy transport and/or as a medium for recovering energy.

Abstract: At least part of the heat energy contained in the exhaust gases of a diesel engine provided with turbo apparatus is recovered before leading the exhaust gases into the turbo apparatus, and at least the major part of the recovered heat energy is used for producing secondary energy to be availed of independent of the production of mechanical energy by the engine. The heat energy recovered can, with advantage, be utilized for hot water or steam production.