Abstract: A Stirling engine which has an expansion cylinder and a compression cylinder with an expansion piston and a compression piston, respectively, that have a fixed phase difference between them, where the expansion cylinder and the compression cylinder are connected through a heater, a regenerator, and a cooler, a fixed amount of working fluid is sealed in the expansion cylinder and a compression cylinder, and the engine is driven by heating or cooling the working fluid with the heater or the cooler, and in the above Stirling engine, the heater for heating the working fluid includes a combustion chamber attached to the expansion cylinder, a burner for jetting a combustible substance into the combustion chamber, a plurality of heat exchanger pipes for forming a plurality of passages for the working fluid to connect through between the expansion cylinder and the regenerator by turning back on themselves, in order to heat the working fluid with the high temperature gas from the burner, and a cylinder head for instal

Abstract: A heat exchanger including a serpentine heat transfer tube embedded in a fluidized bed contained in a vertical casing. The heat transfer pipe has a construction such that fluid undergoing heat exchange and particles of the fluidized bed do not move straightforwardly from an inlet port at the bottom of the casing toward an exit port at the top of the casing. The heat transfer tube includes a horizontal portion extending through a vacant space in the vertical casing above the fluidized bed, and this horizontal portion is provided with a plurality of spaced inclined fins which overlap with each other when viewed from above.