A Stirling engine comprising a first cylinder comprising a piston configured to separate at least two expansion or compression chambers of the first cylinder, and a second cylinder comprising a piston configured to separate at least two expansion or compression chambers of the second cylinder. The pistons of the first and second cylinders are connected, such that the first and second cylinders form a first piston assembly. Each chamber of the first cylinder is fluidly connected to a chamber of a first cylinder of a second piston assembly such that a working fluid to be compressed/expanded can flow between the fluidly connected chambers of the first and second piston assemblies. Each chamber of the second cylinder is fluidly connected to a chamber of a second cylinder of a third piston assembly such that a working fluid to be compressed/expanded can flow between the fluidly connected chambers of the first and third piston assemblies. The first cylinder and the second cylinder of the first piston assembly are each configured as an expansion cylinder or a compression cylinder.

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.

Aircraft with an emission-free drive and method for emission-free driving of an aircraft. The aircraft includes an aircraft thruster structured and arranged to generate thrust force on the aircraft, an aircraft lift device structured and arranged to generate lift on the aircraft, and a heat engine, which is structured and arranged to convert thermal energy into kinetic energy to drive the aircraft thruster, that includes at least one flat-plate Stirling engine drivable by solar thermal radiation.

Aircraft with an emission-free drive and method for emission-free driving of an aircraft. The aircraft includes a drive device structured and arranged to generate thrust, a lift device structured and arranged to generate lift, and a heat engine structured and arranged to convert thermal energy into kinetic energy to drive the drive device. The heat engine includes at least one flat-plate Stirling engine drivable by solar thermal radiation.

A rotary heat engine is comprised of a central crankshaft, a plurality of cylinder assemblies, and a plurality of heat exchanger assemblies. The central crankshaft has first end and a second end defining an axis of rotation. The plurality of cylinder assemblies are coupled to the central crankshaft. The plurality of heat exchanger assemblies are each associated with the plurality of cylinder assemblies, respectively.

The slow-actuation mechanical liquid piston heat pump (1) with a blind liquid cylinder (8) in which a double-acting hydraulic piston (10) translates which is secured to a connecting rod (11) connected to connecting rod actuating means (144), a piston (10) forming with a cylinder (8) a compressor hydraulic variable volume (12) which communicates with a compressor gas and liquid reservoir (14) in which are housed heat exchange and accumulation means (16) to form a compressor (3), and a expander hydraulic variable volume (134) which communicates with a expander gas and liquid reservoir (137) in which are housed expander heat exchange and accumulation means (139) to form an expander (4).

A Stirling engine comprising a first cylinder comprising a piston configured to separate at least two expansion or compression chambers of the first cylinder, and a second cylinder comprising a piston configured to separate at least two expansion or compression chambers of the second cylinder. The pistons of the first and second cylinders are connected, such that the first and second cylinders form a first piston assembly. Each chamber of the first cylinder is fluidly connected to a chamber of a first cylinder of a second piston assembly such that a working fluid to be compressed/expanded can flow between the fluidly connected chambers of the first and second piston assemblies. Each chamber of the second cylinder is fluidly connected to a chamber of a second cylinder of a third piston assembly such that a working fluid to be compressed/expanded can flow between the fluidly connected chambers of the first and third piston assemblies. The first cylinder and the second cylinder of the first piston assembly are each configured as an expansion cylinder or a compression cylinder.

A method of operating a mechanical heat engine according to an internally reversible thermodynamic cycle may comprise four piston-cylinders, with extending connecting rods of identical stroke lengths such that three of the piston-cylinder systems have an identical bore and the fourth cylinder has a smaller bore. According to such a method, the smaller-bore piston-cylinder is connected via the piston rod to an adjacent piston-cylinder with the rods fully extended one full stroke length; and the remaining piston-cylinders are connected via the piston rod, with the rods extended less than a full stroke length.