High Performance Free-Piston Stirling Engines Unrivalled Performance Energy Efficient Compact Robust Long-Lived Experience the Benefits of Unique Free-Piston Stirling Technology
Benefits of Patented Sunpower Technology Over Kinematic or Other Free-Piston Designs Sunpower free-piston Stirling engines are based on patented design features which have evolved into today s technology and an array of available prototypes. Sunpower designs are highly differentiated from conventional kinematic Stirling engines. Also, because Sunpower engines operate on gas bearings, use compact linear alternators and have a simple mechanical configuration, they offer significant benefits over other free-piston designs. By comparison, kinematic Stirling engines are complicated and expensive to build, and require a lubricant, seals and mechanical bearings which combine to restrict performance and limit life. Also, power output is difficult to change in the kinematic design. Sunpower s unique combination of gas bearings, compliance and compact linear alternator delivers the highest efficiency, lowest mass free-piston Stirling engines available. Sunpower free-piston Stirling engine technology is protected by more than 30 United States patents and 80 international patents. Product Development Support Sunpower s free-piston Stirling engine manufacturing organization is supported by a vibrant R&D group who work closely with customers to develop new solutions or engineer Sunpower s engines into new products. Sunpower also maintains a healthy intellectual property/licensing business which can offer customers unique and exclusive positions to our intellectual property. Sunpower s free-piston technology is being applied in areas such as cryocoolers and linear compressors, power generation and household refrigeration. Some applications include the world s most efficient refrigerator on sale internationally; natural gas-fueled household cogeneration systems scheduled to enter the market in 2007; and nuclear space power systems. The commercialization of innovative new technologies enabling unique products requires partnerships and collaboration. For any new product, Sunpower s engineering team is available to work directly with partners at all stages, from proof-of-concept demonstration to design for manufacturer and manufacturing start-up. Sunpower Free-Piston Stirling Engine Prototype Availability Prototype Model Power (nominal) Temperature Ratio (Th/Tc) Efficiency Heat Source Heat Rejection Hermetically Sealed EE-35 42W e 2.7 32% Electric Heater Air/Water Cooling No 1.4 kg 52 x 157 Mass Dimensions, Diameter x Length in mm (nominal) EE-35-H 42We 2.7 32% EE-80 95We 3.0 36% Propane/JP-8 Burner Electric Heater/ Propane Burner Air/Water Cooling Yes 0.6 kg 50 x 142 Air/Water Cooling No 3.7 kg 69 x 193 EE-80-H(*) 95W e 3.0 36% TBD Air/Water Cooling Yes 1.0 kg 65 x 186 EG-1000 1000W e 2.7 32% Propane Burner Water Cooling No 35 kg 270 x 435 Source: SY Kim., James Huth, James G. Wood; Performance Characterization of Sunpower Free-Piston Stirling Engines, Sunpower Inc. (*) Projected Values. For the latest information on Sunpower products, services, corporate news and our online library, visit our Web site at www.sunpower.com. 2
Measured Performance, EE-35 and EE-35-H EE-35 engine with pressure vessel removed Measured Performance, EE-80 and EE-80-H EE-80 engines, opposed pair Measured Performance, EG-1000 EG-1000 engine with non-recuperative propane burner 3
Sunpower Advantages Over Conventional Kinematic and Other Free-Piston Designs Patented, non-contact gas bearing compliant design Compliant displacer floats on gas bearings, allowing non-contact operation Eliminates lubrication Uses space-efficient planar spring Reduces number of critical alignments Simplifies manufacturing Improves efficiency Piston support on gas bearings enables non-contact operation Highly efficient, low-mass linear alternator with permanent magnet for direct AC output Reduced weight through use of efficient copper coil with no end turns and zero mean lamination flux Minimal power loss because moving magnets never leave poles Lightweight, compact size Workplace diameter is independent of displacer spring Unmatched power-to-mass ratio Configurable to a variety of heat sources depending on application requirements New designs can be developed and engineered into unique new products Current commercial, military and aerospace applications use three different prototypes that are available for purchase Sunpower Products and Fuel Source Alternatives Product Development Potential Automotive pre-warmer, battery charger Autonomous consumer and commercial appliances Electric generation, biomass Electric generation, distributed, grid connected Electric generation, off-grid Electric generation, solar thermal Fuel-fired battery Fuel-fired UPS (uninterruptible power supply) Heat pump, biomass fueled Heat pump, residential Vehicle APU (auxiliary power supply) Fuel Source Gasoline, diesel Wood pellets, unprocessed biomass Solar, solar/natural gas hybrid Butane, propane, methanol, kerosene/diesel Butane, propane, kerosene/diesel Wood pellets, unprocessed biomass Gasoline, diesel Sunpower free-piston Stirling engines now in use or in process offer many product development opportunities in diverse markets using a variety of fuels. 4
For more than 30 years Sunpower, Inc., the originator of free-piston Stirling engines, has developed and delivered fully engineered prototypes and preproduction engines for a variety of applications in aerospace, military, household appliance and research industries. Milestones in Free-Piston Stirling Engine Development at Sunpower William Beale invents the free-piston Stirling engine and is awarded U.S. Patent 3,552,120 RE-1000, the first mature free-piston Stirling engine; delivered Design, development and testing of machines from 35W to 7.5kW, and proven operation on numerous heat sources including solar, gaseous and liquid fossil fuels, biomass and heat pipes First demonstration of a tuned dynamic vibration absorber Demonstration of stand-alone diesel fueled free-piston Stirling engine generator to the US Army, First use of a heat pipe heater head Demonstration of high-frequency engine operation (115Hz) Demonstration of balanced opposed configuration engine arrangement First successful application of on-sun solar powered free-piston Stirling engine (development units run through 1994) Licensee completes field trial for first free-piston Stirling engine-based household cogeneration appliance Manufactured cryocooler launched on the 2002 RHESSI mission Demonstration of and improvement on highest efficiency of small free-piston Stirling engine achieved to date Demonstration of and improvement on the highest power per unit mass of small free-piston Stirling engine achieved to date Receipt of NASA funded program to develop next generation Advanced Stirling Convertor (ASC) Free-piston linear alternator technology available in household refrigerators Demonstration of dual opposed, low vibration free-piston Stirling engine configuration at Space Technology and Applications International Forum Free-piston Stirling cooler technology commercially available Demonstration of 20% efficiency of JP-8 to electric power out in a prototype Wearable Power Supply for the US Department of Defense (DoD) 1971 1978 1980 to present 1985 1987 1988 1989 1989-1994 2001 2002 2003-2005 2003-2005 2003 2003 2004 2004 2005 5
Working with Sunpower Sunpower s free-piston Stirling engine prototypes, R&D services and intellectual property are sold direct from our corporate development center in Athens, Ohio USA. Evaluation prototypes for selected products are available to qualified customers. For information please contact Sunpower, Inc. 182 Mill Street,Athens, Ohio 45701 USA P: 740-594-2221 F: 740-593-7531 www.sunpower.com info@sunpower.com Sunpower products are precision manufactured and tested in a modern production facility adjacent to our research, development and administrative center in Athens, Ohio USA. Manufacturing proximity provides our customers with the highest level of flexibility to meet customization demands. Sunpower is a world-leading developer of energy efficient, environmentally friendly, free-piston machines for power generation and cooling.these machines include free-piston Stirling engines and cryocoolers, pulse tube cryocoolers, and linear compressors.the company is comprised of manufacturing, contract R&D, and intellectual property licensing departments. Sunpower is privately held and is situated in Athens, Ohio USA. This brochure meets EPA and FTC guidelines for recycled coated paper. '2005 Sunpower Inc. 09/05 OW7743