High Performance Free-Piston Stirling Engines

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
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 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.
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.
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.
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 Av ailability
Dimensions,
Diameter x Length
in mm (nominal)
Prototype
Model
Power
(nominal)
Temperature
Ratio (Th/Tc)
Efficiency
Heat Source
Heat Rejection
Hermetically
Sealed
Mass
EE-35
42We
2.7
32%
Electric Heater
Air/Water Cooling
No
1.4 kg
52 x 157
EE-35-H
42We
2.7
32%
Propane/JP-8
Burner
Air/Water Cooling
Yes
0.6 kg
50 x 142
EE-80
95We
3.0
36%
Electric Heater/
Propane Burner
Air/Water Cooling
No
3.7 kg
69 x 193
EE-80-H(*)
95We
3.0
36%
TBD
Air/Water Cooling
Yes
1.0 kg
65 x 186
EG-1000
1000We
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.
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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
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Sunpower Advantages Over Conventional Kinematic
and Other Free-Piston Designs
Patented, non-contact gas bearing compliant design
Lightweight, compact size
—Compliant displacer floats on gas bearings,
allowing non-contact operation
—Workplace diameter is independent of
displacer spring
—Eliminates lubrication
Unmatched power-to-mass ratio
—Uses space-efficient planar spring
Configurable to a variety of heat sources
depending on application requirements
—Reduces number of critical alignments
—Simplifies manufacturing
New designs can be developed and engineered
into unique new products
—Improves efficiency
—Piston support on gas bearings enables
non-contact operation
Current commercial, military and aerospace
applications use three different prototypes that
are available for purchase
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
Sunpower Products and Fuel Source Alternatives
Fuel Source
Product Development Potential
Automotive pre-warmer, battery charger
Gasoline, diesel
Autonomous consumer and commercial appliances
Natural gas, LPG, propane
Electric generation, biomass
Wood pellets, unprocessed biomass
Electric generation, distributed, grid connected
Natural gas, LPG, propane
Electric generation, off-grid
Natural gas, LPG, propane
Electric generation, solar thermal
Solar, solar/natural gas hybrid
Fuel-fired battery
Butane, propane, methanol, kerosene/diesel
Fuel-fired UPS (uninterruptible power supply)
Butane, propane, kerosene/diesel
Heat pump, biomass fueled
Wood pellets, unprocessed biomass
Heat pump, residential
Natural gas, LPG, propane
Vehicle APU (auxiliary power supply)
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.
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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
1971
RE-1000, the first mature free-piston Stirling engine; delivered
1978
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
1980 to
present
First demonstration of a tuned dynamic vibration absorber
1985
Demonstration of stand-alone diesel fueled free-piston Stirling engine
generator to the US Army, First use of a heat pipe heater head
1987
Demonstration of high-frequency engine operation (115Hz)
1988
Demonstration of balanced opposed configuration engine arrangement
1989
First successful application of on-sun solar powered free-piston Stirling engine
(development units run through 1994)
19891994
Licensee completes field trial for first free-piston Stirling engine-based
household cogeneration appliance
2001
Manufactured cryocooler launched on the 2002 RHESSI mission
2002
Demonstration of and improvement on highest efficiency of
small free-piston Stirling engine achieved to date
20032005
Demonstration of and improvement on the highest power per unit mass
of small free-piston Stirling engine achieved to date
20032005
Receipt of NASA funded program to develop next generation Advanced Stirling Convertor (ASC)
2003
Free-piston linear alternator technology available in household refrigerators
2003
Demonstration of dual opposed, low vibration free-piston Stirling engine configuration
at Space Technology and Applications International Forum
2004
Free-piston Stirling cooler technology commercially available
2004
Demonstration of 20% efficiency of JP-8 to electric power out in a prototype
Wearable Power Supply for the US Department of Defense (DoD)
2005
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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.
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'2005 Sunpower Inc. 09/05 OW7743