Sunpower was founded in Athens, Ohio based on the technology developed by a professor of mechanical engineering at Ohio University, William Beale. Mr. Beale was teaching a class on the principles of the Stirling engine when it occurred to him there could be a better way. In 1964 Mr. Beale developed a working prototype of what he would call the “Free-Piston Stirling Engine” (FPSE). Mr. Beale applied for and was granted a patent for this invention. He continued to improve upon the design and consider the potential applications while remaining as a professor at the University. In 1974, he created Sunpower and gave this company his full-time professional attention for the next 42 years.
Sunpower went through a period of technology development and design refinements from the mid 70’s to late 90’s. The primary driving force for the business in this timeframe, from Mr. Beale’s perspective, was to keep the doors open and drive towards a solution which would put a Sunpower FPSE system in the home of the average person. The company ultimately did not succeed in this lofty goal, yet the company did succeed in pulling together an amazing cast of employees from all over the world who would go on to lay the extensive technical foundation needed to implement the FPSE technology. Many necessary technologies and processes were learned in this timeframe, including: gas bearings, linear alternator, system simulation, regenerator design, regenerator fabrication, brazing technology, high temperature metals, Stirling engine control, resonate spring design, and others. On the cryocooler side of the business, the late 90’s is when the Sunpower cryocooler program grew from a working concept to a robust engineering design.
Also in the late 1990’s, Sunpower decided to license its FPSE technology for the European micro combined heat and power (mCHP) market. The mCHP industry in Europe and Asia grew significantly from 2000 until 2018, with fuel cell technology appearing to win the battle over Stirling to date.
By the early 2000’s, Sunpower had developed a robust design for both their cryocoolers and FPSEs that could serve a limited market. In this timeframe, the Sunpower cryocooler program developed the manufacturing experience to produce reliable cryocoolers in volume. The CryoTel® CT was introduced in 2001, and the RHESSI M87 cryocooler was launched in 2002, which is still operating to date. The CryoTel MT was introduced in 2003, followed by the CryoTel GT in 2005.
On the engine side, Sunpower had a relationship with NASA from very early on in the company’s formation, but it was the early 2000’s where this relationship grew considerably with the development and further refinement of the Advanced Stirling Convertor (ASC) from 2004 until 2016. Based on learnings from the NASA collaboration, Sunpower’s FPSE technology went through further technological improvement and advancement in this timeframe.
In 2010, Sunpower saw a number of new cryocooler applications successfully gain market traction and demonstrate a need for cryocoolers in temperature range and heat lift capabilities. Applications which were interested in Sunpower products included: Low noise amplifiers, biological sample cooling, semiconductor manufacturing, imaging and mass spectrometry, nuclear magnetic radiation, refrigeration, environmental testing, laser cooling, gas chromatography, pharmaceutical processing, medical cryoablation, telecommunications, high temperature superconductivity, radiation detection, infrared detection, gas liquefaction, SQUID detection, optics and more. A number of notable terrestrial and space applications chose the CryoTel line of cryocoolers for high performance instruments.
In 2015 the Beale family sold Sunpower to Ametek. Ametek has significantly increased the volume of Sunpower cryocoolers used in the Ametek ORTEC line of nuclear instrumentation. Sunpower continues to work with Ametek towards implementation into additional product lines.
In 2016, Sunpower began work on the ARPA-E GENSETS program which led to a further improvement of the engine design with regard to higher efficiencies and a lower cost design in volume. The improvements made during this project may finally make mCHP feasible for the Stirling engine and bring a formidable competitor to fuel cells.
In 2018 Sunpower received the Kilopower contract from NASA to further the work of the ASC program towards a space FSPE.