William T. Beale (1928 – 2016)

William Beale was a mechanical engineering professor at Ohio University in the 1960's. In 1964 he invented one of the most ingenious external heat source engines yet devised – the Free Piston Stirling Engine. Based on this invention he founded the company Sunpower, Inc . in 1974, which over the years developed many innovative, high efficiency heat engines and cryocoolers, using various external heat sources, including solar and wood pellets.
William Beale was a man of ideas and actions whose mind never stopped looking for ways to improve the world even to the end (Refer to his 2012 Ohio Patent Legacy Award interview. He lived what he preached.
At the memorial service held on 24 September 2016, William's son, Dan Beale, presented the following Remarks at the memorial service for my father .

William T. Beale – 1977

William T. Beale – 2016

I visited William a few weeks before his passing, and he sent me the following statement which he requested that I present at the 2016 ISEC , to which I have added some links:

Statement by William (July 2016):
I was happy to see that there are so many keynote speeches scheduled at ISEC 2016 from free piston Stirling companies. I gather that free piston products dominate certain niche markets. My goal in this statement is to point out that mass markets are now within reach.

It seems to me possible to dramatically simplify your free piston designs, stamp out excess cost and attack much larger markets. Some obvious steps present themselves. The first - examine what free piston products performed best in the past in terms of balance, sealing, centering, heat exchanger designs and so forth. Look at what NASA chose for deep space power - and the remarkable performance they achieved.

Consider the free piston alpha, which beats Diesel as a vehicle power plant, according to NASA technical memorandum 82992 , and also provides high efficiency in a very wide range of sizes from 100 Watts to megawatts, and quick response to load.

Revisit the 1985 text " Free Piston Stirling Engines " by Walker and Senft, to see how well some of the cheap early machines performed, and how versatile these engines were in many applications. An example from the book is the simple hydrogen-charged free cylinder engine, with its automatic load matching and high specific power. Also look up Biowatt , an early wood-pellet fired system.

By learning from such past efforts cost may be reduced greatly, creating big mass market opportunities. Foremost among these, in the carbon-constrained world of the near future, is the biomass-fired home power plant which complements photovoltaics. Any fuel, with or without pre-processing, could be used to power a free piston Stirling that automatically recharges a home battery bank when charge levels get low. If pyrolysis is used for pre-processing and the resulting biochar is returned to the soil, one has the ideal future power plant: un-interruptable, maintenance-free and carbon-negative in all sizes from domestic on up.

The free piston Stirling community history gives examples of opportunities to simplify designs and slash costs to a fraction of the current values. If you succeed in that, you'll see that the age of commercial Stirling is just beginning.

Best wishes to all
William T. Beale (1928-2016)


Based on discussions with David Berchowitz, I wish to add the following to William's statement concerning the free-cylinder water pump . In this engine a heavy internal mass provides the reaction force driving the cylinder which is directly connected to the water pump. It has built in power adjustment and responds to load automatically. All other engines require a transmission and complicated control mechanisms to do this. Furthermore, there is no other mechanical heat engine that we know of that operates from infinite load to zero without either stalling or destroying itself.
Another attractive feature of the free cylinder system is that it can be constructed from inexpensive easy-to-obtain components. In fact, the entire pump housing can be fabricated from ordinary PVC piping and fixtures. The reliability, simplicity and low cost of this engine makes it eminently suitable for application in developing countries, and in the 1970's it was extensively tested both in the field and in the laboratory (Refer to the 1979 presentation by William A Free-Cylinder Stirling Engine for Solar Powered Water Pumps ).