An energy conversion apparatus may include an engine assembly, such as a monolithic engine assembly. The engine assembly may include a first monolithic body segment and a plurality of second monolithic body segments directly coupled or directly couplable to the first monolithic body segment. The first monolithic body segment may define a combustion chamber and a recirculation pathway in fluid communication with the combustion chamber. The recirculation pathway may be configured to recirculate combustion gas through the combustion chamber. The plurality of second monolithic body segments may respectively define at least a portion of a piston chamber and a plurality of working-fluid pathways fluidly communicating with the piston chamber.

An energy conversion apparatus may include an engine assembly, such as a monolithic engine assembly. The engine assembly may include a first monolithic body segment and a plurality of second monolithic body segments directly coupled or directly couplable to the first monolithic body segment. The first monolithic body segment may define a combustion chamber and a recirculation pathway in fluid communication with the combustion chamber. The recirculation pathway may be configured to recirculate combustion gas through the combustion chamber. The plurality of second monolithic body segments may respectively define at least a portion of a piston chamber and a plurality of working-fluid pathways fluidly communicating with the piston chamber.

A multi-stage Stirling cycle machine and a steady-state operating parameter control method therefor are disclosed. In the Stirling cycle machine, a mechanical energy input piston, a mechanical energy transfer double-acting free piston, and a mechanical energy output piston constitute a plurality of Stirling working units which are arranged in stages. The mechanical energy input piston is connected to a mechanical energy input apparatus. The mechanical energy output piston is connected to a mechanical energy output apparatus. When the Stirling cycle machine is used as an engine, a relatively small amount of mechanical energy is input into a mechanical energy input piston in a set of pistons, the mechanical energy is amplified by a multi-stage Stirling unit, and a relatively large amount of mechanical energy is then output by a mechanical energy output piston.

A multi-stage Stirling cycle machine and a steady-state operating parameter control method therefor are disclosed. In the Stirling cycle machine, a mechanical energy input piston, a mechanical energy transfer double-acting free piston, and a mechanical energy output piston constitute a plurality of Stirling working units which are arranged in stages. The mechanical energy input piston is connected to a mechanical energy input apparatus. The mechanical energy output piston is connected to a mechanical energy output apparatus. When the Stirling cycle machine is used as an engine, a relatively small amount of mechanical energy is input into a mechanical energy input piston in a set of pistons, the mechanical energy is amplified by a multi-stage Stirling unit, and a relatively large amount of mechanical energy is then output by a mechanical energy output piston.

A monolithic heat exchanger body for inputting heat to a closed-cycle engine includes heating walls and heat sink, such as heat transfer regions. The heating walls are configured and arranged in an array of spirals or spiral arcs relative to a longitudinal axis of an inlet plenum. Adjacent portions of the heating walls respectively define corresponding heating fluid pathways fluidly communicating with the inlet plenum. At least a portion of the heat sink is disposed about at least a portion of the monolithic heat exchanger body. The heat sink includes working-fluid bodies including working-fluid pathways that have a heat transfer relationship with the heating fluid pathways. Respective ones of the heat transfer regions have a heat transfer relationship with a corresponding semiannular portion of the heating fluid pathways. Respective ones of the heat transfer regions include working-fluid pathways fluidly communicating between a heat input region and a heat extraction region.

A monolithic heat exchanger body for inputting heat to a closed-cycle engine includes heating walls and heat sink, such as heat transfer regions. The heating walls are configured and arranged in an array of spirals or spiral arcs relative to a longitudinal axis of an inlet plenum. Adjacent portions of the heating walls respectively define corresponding heating fluid pathways fluidly communicating with the inlet plenum. At least a portion of the heat sink is disposed about at least a portion of the monolithic heat exchanger body. The heat sink includes working-fluid bodies including working-fluid pathways that have a heat transfer relationship with the heating fluid pathways. Respective ones of the heat transfer regions have a heat transfer relationship with a corresponding semiannular portion of the heating fluid pathways. Respective ones of the heat transfer regions include working-fluid pathways fluidly communicating between a heat input region and a heat extraction region.

A system for energy conversion, the system including a closed cycle engine containing a volume of working fluid, the engine comprising a first chamber defining an expansion chamber and a second chamber defining a compression chamber each separated by a piston attached to a connection member of a piston assembly, and wherein the engine comprises a heater body in thermal communication with the first chamber, and further wherein the engine comprises a cold side heat exchanger in thermal communication with the second chamber, and wherein a third chamber is defined within the piston, wherein the third chamber is in selective flow communication with the first chamber, the second chamber, or both.

A gas purifying apparatus has: a compressing unit for compressing a gas in which an atmosphere or inert gas and a substance vaporized by heating have been mixed; and an expanding unit for liquefying the substance by expanding the gas compressed by the compressing unit, wherein the gas in which the substance has been reduced is obtained

A gas purifying apparatus has: a compressing unit for compressing a gas in which an atmosphere or inert gas and a substance vaporized by heating have been mixed; and an expanding unit for liquefying the substance by expanding the gas compressed by the compressing unit, wherein the gas in which the substance has been reduced is obtained

A gas purifying apparatus has: a compressing unit for corn pressing a gas in which an atmosphere or inert gas and a substance vaporized by heating have been mixed; and an expanding unit for liquefying the substance by expanding the gas compressed by the compressing unit, wherein the gas in which the substance has been reduced is obtained.