Abstract: A modular thermal apparatus for performing transformation between thermal and acoustic energy is disclosed and includes a housing, first and second fluid ducts extending therethrough, and a regenerator having axially extending regenerator fluid passages. A first heat exchanger conducts thermal energy in the axial direction and includes transversely oriented fluid passages extending through a thermally conductive body and changing direction within the body to terminate axially aligned with the regenerator fluid passages. The apparatus also includes a second heat exchanger having fluid passages extending through a thermally conductive body and terminating in fluid communication with the regenerator fluid passages. Thermal energy is transferred between the heat exchangers and an external thermal energy source or sink. The housing withstands a pressure associated with a pressurized working gas and the fluid ducts provide for connection of the apparatus as a module within an acoustic power loop.

Abstract: An electromechanical transducer apparatus is disclosed and includes a housing. A static portion is substantially immobilized within the housing and includes a magnetic flux generator for generating magnetic flux, a pair of pole pieces for coupling magnetic flux through at least one of a first magnetic circuit and a second magnetic circuit, and a coil disposed to electromagnetically interact with one of the magnetic circuits. The static portion is thermally coupled to the housing via a low thermal resistance path to permit removal of heat. A movable portion includes first and second closing pieces separated from the pole pieces by first and second gaps. The closing pieces are mechanically coupled and supported for reciprocating motion about an equilibrium position which varies the gaps to cause a variation in magnetic reluctance in each of the first and second magnetic circuits.

Abstract: A thermoacoustic transducer includes a mechanical converter providing power conversion between acoustic and mechanical power and includes a diaphragm defining a compression and an expansion chamber. A thermal converter including a flow passage having a regenerator portion is thermally coupled for conversion between acoustic and thermal power. The mechanical converter is in fluid communication with the flow passage through transmission ducts completing an acoustic power loop having a volume containing a working gas. A transmission duct cross-sectional area is less than a regenerator flow area, which is less than a diaphragm surface area. The diaphragm undergoes resilient displacement causing pressure oscillations within the volume. The power loop is configured to cause one location along the loop to have anti-phase pressure oscillations to pressure oscillations in the mechanical converter.

Abstract: An electromechanical transducer apparatus is disclosed and includes a housing. A static portion is substantially immobilized within the housing and includes a magnetic flux generator for generating magnetic flux, a pair of pole pieces for coupling magnetic flux through at least one of a first magnetic circuit and a second magnetic circuit, and a coil disposed to electromagnetically interact with one of the magnetic circuits. The static portion is thermally coupled to the housing via a low thermal resistance path to permit removal of heat. A movable portion includes first and second closing pieces separated from the pole pieces by first and second gaps. The closing pieces are mechanically coupled and supported for reciprocating motion about an equilibrium position which varies the gaps to cause a variation in magnetic reluctance in each of the first and second magnetic circuits.

Abstract: A thermoacoustic transducer includes a mechanical converter providing power conversion between acoustic and mechanical power and includes a diaphragm defining a compression and an expansion chamber. A thermal converter including a flow passage having a regenerator portion is thermally coupled for conversion between acoustic and thermal power. The mechanical converter is in fluid communication with the flow passage through transmission ducts completing an acoustic power loop having a volume containing a working gas. A transmission duct cross-sectional area is less than a regenerator flow area, which is less than a diaphragm surface area. The diaphragm undergoes resilient displacement causing pressure oscillations within the volume. The power loop is configured to cause one location along the loop to have anti-phase pressure oscillations to pressure oscillations in the mechanical converter.