Abstract: In an apparatus for converting thermal energy from a heat source into mechanical energy by means of a thermodynamic cycle using a working medium which is guided in the cycle and in that context experiences a changing pressure, wherein a saturated steam temperature value of the working medium is associated with the respective pressure, and an expansion device for expanding the working medium from an elevated pressure to a lower pressure, wherein after expansion to the lower pressure the working medium has a waste steam temperature, there is provided an adjustment device for setting the waste steam temperature to a defined waste steam temperature value above the saturated steam temperature value associated with the lower pressure.