Abstract: An improved multi-stage turbine system is provided which includes a high pressure turbine stage assembly and at least one lower pressure turbine stage assembly. Each of these turbine assemblies preferably has an inlet opening for introducing a thermodynamic medium in the form of a vapor and a discharge opening for discharging the thermodynamic medium from the turbine assembly at a reduced temperature and pressure. Each of the turbine assemblies is typically mounted on a rotatable shaft and these shafts may be coaxially aligned. An assembly such as a clutch may be provided for releasably interlocking the shafts. The thermodynamic medium is transported, when operating conditions are suitable, from the discharge opening of the high pressure turbine assembly to the inlet opening of the lower pressure turbine assembly.

Abstract: An improved engine system is provided which includes a synthetic low temperature sink that is developed in conjunction with an absorbtion-refrigeration subsystem having inputs from an external low-grade heat energy supply and from an external source of cooling fluid. A low temperature engine is included which has a high temperature end that is in heat exchange communication with the external heat energy source and a low temperature end in heat exchange communication with the synthetic sink provided by the absorbtion-refrigeration subsystem. By this invention, it is possible to vary the sink temperature as desired, including temperatures that are lower than ambient temperatures such as that of the external cooling source. This feature enables the use of an external heat input source that is of a very low grade because an advantageously low heat sink temperature can be selected.