Abstract: A heat-power engine and system using a condensable vapor as the working fluid has a cylinder with a piston operating therein characterized in that the heat input communicates with the clearance volume of the cylinder, and all of the working fluid, mechanically and thermodynamically possible, is removed from the cylinder adjacent and/or following bottom dead center of the piston.

Abstract: A heat-power engine and system using a condensable vapor as the working fluid has a cylinder with a piston operating therein characterized in that the heat input communicates with the swept volume of the engine in a zone comprising the clearance volume of the cylinder at the top dead center of the piston.

Abstract: An improved Stirling cycle type engine is provided wherein the working fluid is a condensible fluid such as steam and a portion of the steam is condensed prior to the introduction of the steam into the cold cylinder zone. Before and/or during compression of the steam in the cold cylinder zone, water is injected in an amount equal to, greater than or less than the amount condensed.

Abstract: Steam or other condensable vapor heated to a maximum temperature at a maximum pressure permitted by the system is expanded to a lower pressure in a positive displacement expander; the partially expanded fluid is then further expanded in a turbine, a portion of the fluid in the turbine is withdrawn and directed to a positive displacement compressor and compressed to the maximum operating pressure while introducing the condensate of the remaining portion of the fluid into the compressor. The compressed fluid is then reheated to maximum temperature and the cycle repeats.