To solve the problem with a conventional system, wherein when using the waste heat of about 300°C exhausted from an internal combustion engine of a ship or the like, there is a limit on the pressure of steam obtained from a heat exchanger and a temperature condition, and heat efficiency may be impaired in a middle-scaled axial flow steam turbine.

In the out-flow type radial steam turbine in which a flow direction of the operating steam of the steam turbine progresses to the external periphery from the internal periphery, the heat efficiency becomes favorable even at a heat source of the exhaust gas of about 300°C of the diesel engine. By employing a method (Fig.6) in which, in particular, a plurality of rotating plates can be firmly attached to a rotation shaft, waste heat energy can effectively be converted into the drive energy of the steam turbine, and a main machine is backed up, or driven as a sub-machine.