A process, device and system are provided for utilizing waste heat from a waste heat source, especially from an internal combustion engine, by a coolant being heated and by this heat being used to drive a turbine. The device utilizes waste heat with a waste heat source (10, 20) cooled by a coolant, with a turbine (11) and with an evaporating device (16) for the coolant. To increase the efficiency of such a process and such a device and system, and to reduce the design effort and the maintenance effort, the coolant is evaporated after it leaves the waste heat source (10, 20) and the evaporating means is provided after the waste heat source (10, 20) when viewed in the direction of flow of the coolant.