Milestones

Since the mid ‘70s, Sunpower, Inc., the originator of free-piston Stirling engines, has developed and delivered fully engineered prototypes and preproduction engines for a variety of fields of use in aerospace, military, household appliance and research industries.

Milestones in Free-Piston Stirling Engine Development at Sunpower

1964
William Beale invents the free-piston Stirling engine

1971
Free-Piston Stirling Engine patent 3,552,120 awarded

1974
Sunpower incorporated

1978
RE-1000, the first mature free-piston Stirling engine, delivered

1980 to Present
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

1985
First demonstration of a tuned dynamic vibration absorber

1987
Demonstration of stand-alone diesel fueled free-piston Stirling engine generator to the US Army, first use of a heat pipe heater head

1988
Demonstration of high-frequency engine operation (115Hz)

1989
Demonstration of balanced opposed configuration engine arrangement

1989 to 1994
First successful application of solar powered free-piston Stirling engine (development Units run through 1994)

1999
Sunpower creates cryocooler manufacturing operation

2001
Licensee completed field trial for first free-piston Stirling engine-based household cogeneration appliance

2002
M77 cryocooler launched on the 2002 RHESSI mission

2003
Receipt of NASA funded program to develop next generation Advanced Stirling Convertor (ASC)

Free-piston linear compressor technology available in household refrigerators

2003 to 2005
Demonstration of and improvement on highest efficiency, and highest power per unit mass of small free-piston Stirling engine achieved to date

2003-10
Developed Engines for long range satellites and space exploration

2004
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

2005
Demonstration of 20% efficiency of JP-8 to electric power out in a prototype Wearable Power supply for the US Department of Defense (DoD)

2009
Completion of integration and demonstration to the US Army of a free-piston Stirling engine based, soldier portable, JP-8 fueled generator

2010
Stirling engine-based household cogeneration appliance commercially available

2010
Transitioned from development of Engines for space flight to manufacturing Stirling engines for space flight

2011
Expanded capabilities and throughput with a move to a new state-of-the-art facility

2012
The first successful run of the ASC-E3 Stirling Convertor