Sunpower Corporation

Other

David Ray Gedeon

William T Beale

Roberto O Pellizzari

James Gary Wood

Laurence B Penswick

Kyle B Wilson

Multiple free-piston stirling-cycle machine modules are connected together in double-acting configurations that may be used as engines or heat pumps and scaled to any power level by varying the number of modules. Reciprocating piston assemblies oriented in balanced pairs reduce vibration forces. There are no buffer spaces. Linear motors or generators are packaged inside piston cavities entirely within the module working spaces. The external heat-accepting and heat-rejecting surfaces in one embodiment are directed along inward-facing and outward facing cylinders, and in another embodiment along parallel planes, simplifying thermal connections to the external heat source and sink.

Double-acting modular free-piston stirling machines without buffer spaces

The cool down time for a multi-stage, pulse tube cryocooler is reduced by configuring at least a portion of the acoustic impedance of a selected stage, higher than the first stage, so that it surrounds the cold head of the selected stage. The surrounding acoustic impedance of the selected stage is mounted in thermally conductive connection to the warm region of the selected stage for cooling the acoustic impedance and is fabricated of a high thermal diffusivity, low thermal radiation emissivity material, preferably aluminum.

Multi-stage pulse tube cryocooler with acoustic impedance constructed to reduce transient cool down time and thermal loss

An improved pulse tube cooler having a resonator tube connected in place of a compliance volume or reservoir. The resonator tube has a length substantially equal to an integer multiple of &#xbc; wavelength of an acoustic wave in the working gas within the resonator tube at its operating frequency, temperature and pressure. Preferably, the resonator tube is formed integrally with the inertance tube as a single, integral tube with a length approximately &#xbd; of that wavelength. Also preferably, the integral tube is spaced outwardly from and coiled around the connection of the regenerator to the pulse tube at a cold region of the cooler and the turns of the coil are thermally bonded together to improve heat conduction through the coil.

Pulse tube cooler having &#xbc; wavelength resonator tube instead of reservoir

A displacer spring and displacer/spring assembly for use in an FPSE and with improved wear characteristics. One embodiment calls for the use of a single machined spring operating alternately in a tension mode and a compression mode and wherein the operating frequency of displacer movement can be controlled therewith to a desired resonant frequency. The machined spring of the present invention provides enhanced structural accuracy which, in turn, leads to the elimination of lateral and side loads as compared to prior art wire-wound helical springs.

Machine spring displacer for Stirling cycle machines

A free-piston Stirling engine having a double acting, gas spring system for applying bi-directional, resilient spring forces to the displacer piston rod and also a free-piston Stirling engine having a displacer and power piston which are mechanically resonant at the operating frequency of the engine. The springing system is a gas containing compartment which is formed in communication with the effective end of the displacer rod. An adjustable spool valve arrangement may be formed in the mating walls of the displacer rod and its cylinder for connecting the gas containing compartment with the bounce space during a relatively minor interval of the displacer rod stroke intermediate its extremes for adjustably maintaining the mean position of the displacer at the position at which the interconnection occurs. The resonant system comprises the combination of a displacer and associated spring with the displacer mass and the spring force constant being such that the combination is resonant at the engine operating frequency. Similarly, the power piston may be linked to a gas or mechanically deformable spring wherein that combination is also resonant at the same operating frequency. Preferably, the displacer spring is a gas spring linked to the engine cylinder block. A balanced, multi-piston engine is described which has a power piston spring which comprises a mass of gas in a passage communicating with an end of each of the power piston cylinders.

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Athens, OH, United States of America

David Ray Gedeon