Abstract: The invention relates to an apparatus that includes a first heat exchanger for heating a first heat transfer medium in a first form from a first temperature to a second higher temperature to provide an increased pressure gas, a first mechanical device configured to use the increased pressure gas to provide mechanical energy to one or more primary components, and one or more additional mechanical devices configured to use the increased pressure gas to provide mechanical energy to one or more secondary components. The mechanical device produces spent gas, and a conversion device is operably associated with at least one of the mechanical devices to convert the spent gas to the first form for re-use.