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 for converting between mechanical energy and electrical energy is disclosed and includes first and second magnetic flux generators including pole pieces coupled to direct magnetic flux. Th magnetic flux generators are disposed such that opposite polarity pole pieces are spaced apart in adjacent relation. A pair of reciprocators are coupled for reciprocating movement between the pole pieces and are spaced apart by first and second air gaps. A closing piece completes a magnetic circuit and when the reciprocators are disposed such that the first air gap is smaller than the second air gap, magnetic flux generated by the first magnetic flux generator flows in a first direction via the first air gap through the closing piece. When the reciprocators are disposed such that the second air gap is smaller than the first air gap, magnetic flux generated by the second magnetic flux generator flows in a second opposite direction via the second air gap through the closing piece.

Abstract: A thermal regenerator apparatus is disclosed including a regenerator medium having a plurality of flow passages extending between first and second ports, the flow passages facilitating back and forth fluid flow in a generally transverse direction between the first and second ports while the medium alternatively receives thermal energy from and delivers thermal energy to the fluid. The regenerator medium includes a plurality of overlying foils, each foil having a plurality of channels extending through the foil, the channels having beveled sidewalls. The channels have a width and spacing in the transverse direction and channels in each adjacent overlying foil are transversely offset such that each channel spans between and is in fluid communication with a pair of channels in the adjacent foils and the beveled sidewalls of the channels redirect fluid flow between channels in adjacent foils to form the flow passages.

Abstract: A thermoacoustic transducer apparatus is disclosed including at least one thermal converter operable to provide power conversion between acoustic power and thermal power in a pressurized working gas contained within a working volume, a portion of which extends through the thermal converter. The thermoacoustic transducer is operable to cause a periodic flow in the working gas during operation. The apparatus also includes a reservoir volume in fluid communication with the working volume through a conduit having a working volume end in fluid communication with the working volume and a reservoir volume end in fluid communication with the reservoir volume.

Abstract: An apparatus for exchanging heat with a fluid includes a heat exchanger having first and second opposing surfaces and a plurality of flow passages permitting axial fluid flow between the surfaces. A manifold having an interface surface is in thermal contact with the first surface and includes a thermally conductive body for conducting heat in an axial direction between the interface surface and a heat transmitting surface. A plurality of feed passages extend through the thermally conductive body in a transverse direction, the passages having an inlet for receiving or discharging fluid. A plurality of distribution passages have ends in fluid communication with at least one of the feed passages and openings distributed over the interface surface. The distribution passages are configured to cause a change in fluid flow direction between a transversely directed flow in the feed passages and an axially directed flow at the openings.

Abstract: An apparatus for performing energy transformation between thermal energy and acoustic energy is in a thermoacoustic transducer apparatus is disclosed. The acoustic energy is associated with a periodic flow of a working fluid within an acoustic power loop of the thermoacoustic transducer. The apparatus includes a common central plenum having a first fluid port for providing fluid communication with the acoustic power loop, and a plurality of discrete cylindrical thermal converters radially arranged about the plenum, each thermal converter including a regenerator. The apparatus also includes a second fluid port for providing fluid communication between the thermal converter and the acoustic power loop, and fluid flow passages in fluid communication with the plenum and extending through the regenerator to the second fluid port.

Abstract: A thermoacoustic transducer apparatus is disclosed including at least one thermal converter operable to provide power conversion between acoustic power and thermal power in a pressurized working gas contained within a working volume, a portion of which extends through the thermal converter. The thermoacoustic transducer is operable to cause a periodic flow in the working gas during operation. The apparatus also includes a reservoir volume in fluid communication with the working volume through a conduit having a working volume end in fluid communication with the working volume and a reservoir volume end in fluid communication with the reservoir volume.

Abstract: An apparatus for performing energy transformation between thermal energy and acoustic energy is in a thermoacoustic transducer apparatus is disclosed. The acoustic energy is associated with a periodic flow of a working fluid within an acoustic power loop of the thermoacoustic transducer. The apparatus includes a common central plenum having a first fluid port for providing fluid communication with the acoustic power loop, and a plurality of discrete cylindrical thermal converters radially arranged about the plenum, each thermal converter including a regenerator. The apparatus also includes a second fluid port for providing fluid communication between the thermal converter and the acoustic power loop, and fluid flow passages in fluid communication with the plenum and extending through the regenerator to the second fluid port.

Abstract: An apparatus for exchanging heat with a fluid includes a heat exchanger having first and second opposing surfaces and a plurality of flow passages permitting axial fluid flow between the surfaces. A manifold having an interface surface is in thermal contact with the first surface and includes a thermally conductive body for conducting heat in an axial direction between the interface surface and a heat transmitting surface. A plurality of feed passages extend through the thermally conductive body in a transverse direction, the passages having an inlet for receiving or discharging fluid. A plurality of distribution passages have ends in fluid communication with at least one of the feed passages and openings distributed over the interface surface. The distribution passages are configured to cause a change in fluid flow direction between a transversely directed flow in the feed passages and an axially directed flow at the openings.

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: The apparatus includes a housing, a compression chamber disposed in the housing and having at least a first interface operable to vary a volume of the compression chamber, an expansion chamber disposed in the housing and having a second interface operable to vary a volume of at least the expansion chamber, and a thermal regenerator in fluid communication with each of the compression chamber and the expansion chamber. The thermal regenerator is operable to alternatively receive thermal energy from gas flowing in a first direction through the regenerator and to deliver the thermal energy to gas flowing in a direction opposite to the first direction through the regenerator. The compression chamber, the expansion chamber, and the regenerator together define a working volume for containing a pressurized working gas.

Abstract: A communication passage in a Stirling cycle transducer includes a cylindrical shaped thermal regenerator providing flow paths aligned with a regenerator cylindrical axis for providing periodic gas flow between first and second interfaces of the regenerator. A first heat exchanger conveys gas between a periphery of the heat exchanger and the first interface causing a change of direction of gas flow between radially and axially oriented flow within the regenerator and transfers heat between the gas and an external environment in a direction aligned with the regenerator cylindrical axis. A second heat exchanger conveys gas between a periphery of the heat exchanger and the second interface causing a change of direction of gas flow between radially and axially oriented flow within the regenerator and transfers heat between the external environment and the gas in a direction aligned with the regenerator cylindrical axis.

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: A communication passage in a Stirling cycle transducer includes a cylindrical shaped thermal regenerator providing flow paths aligned with a regenerator cylindrical axis for providing periodic gas flow between first and second interfaces of the regenerator. A first heat exchanger conveys gas between a periphery of the heat exchanger and the first interface causing a change of direction of gas flow between radially and axially oriented flow within the regenerator and transfers heat between the gas and an external environment in a direction aligned with the regenerator cylindrical axis. A second heat exchanger conveys gas between a periphery of the heat exchanger and the second interface causing a change of direction of gas flow between radially and axially oriented flow within the regenerator and transfers heat between the external environment and the gas in a direction aligned with the regenerator cylindrical axis.

Abstract: The apparatus includes a housing, a compression chamber disposed in the housing and having at least a first interface operable to vary a volume of the compression chamber, an expansion chamber disposed in the housing and having a second interface operable to vary a volume of at least the expansion chamber, and a thermal regenerator in fluid communication with each of the compression chamber and the expansion chamber. The thermal regenerator is operable to alternatively receive thermal energy from gas flowing in a first direction through the regenerator and to deliver the thermal energy to gas flowing in a direction opposite to the first direction through the regenerator. The compression chamber, the expansion chamber, and the regenerator together define a working volume for containing a pressurized working gas.