Abstract: A steam engine has a pipe shaped fluid container, a heating and cooling devices respectively provided at a heating and cooling portions of the fluid container, and an output device connected to the fluid container, so that the output device is operated by the fluid pressure change in the fluid container, to generate an electric power. In such a steam engine, the fluid pressure in the fluid container is adjusted such that the fluid pressure does not exceed a saturated vapor pressure at the operating temperature. As a result, unnecessary condensation and liquefaction of the steam due to the increased pressure higher than the saturated vapor pressure can be prevented, to improve performance of the steam engine.

Abstract: In a steam engine having a heating device, a cooling device, and an output device, the output device comprises a piston reciprocally moving by a self-excited fluid vibration of a working fluid in a fluid container. The piston is reciprocally moved by the output device for a certain period before starting an operation of the steam engine, so that the working fluid is moved to an inside space of the heating device. Since the working fluid is surely heated and vaporized by the heating device, the fluid vibration is stably started, and as a result, the operation of the steam engine can be smoothly started.

Abstract: A steam engine has a fluid container, a heating device and a cooling device provided at the fluid container for heating and cooling working fluid filled in the fluid container, so that a part of the working fluid is heated and vaporized to move the liquid-phase working fluid in one direction. When the vaporized steam is cooled and liquidized, the pressure of the working fluid in the fluid container is decreased, to thereby move the liquid-phase working fluid in the backward direction. Kinetic energy is thereby generated by using the back and forth movement of the working fluid.

Abstract: A liquid pump for circulating working fluid (water) in a Rankine cycle comprises a U-shaped fluid vessel having a bending pipe portion and a pair of straight pipe portions, wherein a heating device and a cooling device are provided at one of the straight pipe portions for heating and cooling the water in the fluid vessel. The liquid pump further has a discharge pipe portion and an inlet pipe portion, and check valves are respectively provided in the discharge and inlet pipe portions. The water is vaporized by a heating operation of the heating device to increase pressure of the working fluid in the pump, so that the working fluid is discharged. The vaporized working fluid is then cooled down by the cooling device to decrease the pressure of the working fluid in the pump, so that the working fluid is sucked into the pump.