A multi-stage traveling wave thermoacoustic engine is disclosed. A plurality of heat engine stages are formed as a toroidal spiral cascade of N stages inside a pressure vessel. Each stage feeds into the next stage such that all of the thermoacoustic power cycles past a common set of thermal interfaces multiple times with the single domed pressure vessel. The inventive thermoacoustic engine is simpler and cheaper to manufacture and more reliable due to the minimization of hot joints.

A method and apparatus that reduces the dead volume in a heat engine or heat pump, such as a duplex Stirling or Vuilleumier cycle device, by nesting the components of the displacer and regenerator such that nearly all working fluid is purged from the interstices of the regenerator elements and all other working fluid spaces that are not involved in doing useful work at each portion of the cycle. Particularly, a more scalable and efficient method and apparatus for providing solar air conditioning or refrigeration by means of a heated cylinder that alternately pressurizes and depressurizes a separate cooling cylinder by directly transferring thermally induced pressure changes to that cooling cylinder at optimized times in the cycle, under the control of a numerically controlled actuation system that can cycle at a much lower rate than mechanically coupled or harmonically phased systems.

A Stirling cycle machine. The machine includes at least one rocking drive mechanism which includes: a rocking beam having a rocker pivot, at least one cylinder and at least one piston. The piston is housed within a respective cylinder and is capable of substantially linearly reciprocating within the respective cylinder. Also, the drive mechanism includes at least one coupling assembly having a proximal end and a distal end. The linear motion of the piston is converted to rotary motion of the rocking beam. Also, a crankcase housing the rocking beam and housing a first portion of the coupling assembly is included. The machine also includes a working space housing the at least one cylinder, the at least one piston and a second portion of the coupling assembly. An airlock is included between the workspace and the crankcase and a seal is included for sealing the workspace from the airlock and crankcase. A burner and burner control system is also included for heating the machine and controlling ignition and combustion in the burner.

A Stirling engine with internal regenerator and integral geometry for heat transfer and fluid flow has a displacer piston with a plurality of cavities traversing through the displacer piston and arranged in a specific cross sectional geometry. A heater head has heater fin protrusions that are arranged in the specific geometry, and a cooling bridge has cooler fin protrusions that are in the specific geometry. The displacer piston alternates between the heater head and the cooling bridge, with the cavities of the piston alternately enveloping the heater protrusions and the cooling protrusions, providing more efficient heat transfer to and from the working fluid. Each cavity in the displacer also contains a regenerator core, further improving heat transfer efficiency. The heater fin protrusions may also contain thermally conductive cores. A bellows assembly may also be used to seal the displacer piston from the heater head in order to reduce unswept volume.

An external combustion engine including a burner element, a heater head, a piston cylinder containing a piston, a cooler and a crankcase. The crankcase includes a crankshaft, a piston rod connected to the piston, a drive mechanism for converting the linear motion of the piston rod to rotary motion of the crankshaft and a linear cross-head bearing that is connected rigidly to the piston rod at one end and to the drive mechanism at the other end. Also the external combustion engine includes a piston clearance seal and a piston rod seal unit that has floating rod seals. The piston includes a inner dome to reduce axial heat transfer via radiation and convection.

A Stirling cycle machine. The machine includes at least one rocking drive mechanism which includes: a rocking beam having a rocker pivot, at least one cylinder and at least one piston. The piston is housed within a respective cylinder and is capable of substantially linearly reciprocating within the respective cylinder. Also, the drive mechanism includes at least one coupling assembly having a proximal end and a distal end. The linear motion of the piston is converted to rotary motion of the rocking beam. Also, a crankcase housing the rocking beam and housing a first portion of the coupling assembly is included. The machine also includes a working space housing the at least one cylinder, the at least one piston and a second portion of the coupling assembly. An airlock is included between the workspace and the crankcase and a seal is included for sealing the workspace from the airlock and crankcase. A burner and burner control system is also included for heating the machine and controlling ignition and combustion in the burner.

An annular venturi burner assembly and Stirling engine. The annular venturi burner injects fuel into combustion air flowing axially through a port with an annular cross section. The fuel enters the annular cross-section from the outside diameter. The flow of air through the annular section creates suction that draws the fuel through the ports. A venturi bushing directs the flow of fuel to provide improved and more uniform mixing of fuel and air.

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.

Stirling cycle machine. The machine includes at least one rocking drive mechanism which includes: a rocking beam having a rocker pivot, at least one cylinder and at least one piston. The piston is housed within a respective cylinder and is capable of substantially linearly reciprocating within the respective cylinder. Also, the drive mechanism includes at least one coupling assembly having a proximal end and a distal end. The linear motion of the piston is converted to rotary motion of the rocking beam. Also, a crankcase housing the rocking beam and housing a first portion of the coupling assembly is included. The machine also includes a working space housing the at least one cylinder, the at least one piston and a second portion of the coupling assembly. An airlock is included between the workspace and the crankcase and a seal is included for sealing the workspace from the airlock and crankcase. A burner and burner control system is also included for heating the machine and controlling ignition and combustion in the burner.

Regenerators for Stirling engines and Vuilleumier heat pumps are difficult to reliably manufacture. A regenerator is disclosed in which edges of the regenerator wire meshes are coated with a stabilizing material. The regenerator wire meshes are then sufficiently stable to be machined to the dimensions of the housing. In some embodiments, the material on the outer surface of the edges of the regenerator is relatively thermally insulating to limit heat transfer to the housing.