This operation is out of India and is the only mass produced small steam power unit in the world. The owner is V. K. Desai who operates under the name TinyTech and they stared out with many good ideas, such as having distributed power burning bio-fuels so that every village can process agricultural products locally without the transportation costs of hauling them to a large central factory. The website is interesting and fun to read. Not everyone will agree with the long diatribe and polemic about Gandhi’s philosophy. It is a bit much but thought provoking.
The problem with TinyTech’s steam engines is that the thermal efficiency, as advertised, is a 40 pound water rate, and that is with the new piston valve engine design. As a comparison, the Stanley steamer was in the 25 pound range, the Bryan tractor engine was theoretically 15 pounds, the Doble Triple was designed for 10 pounds, and the Williams dyno tested at 8 pounds, although they claimed 6 pounds. The pounds business is how many pounds of water needs to be evaporated into steam to produce one horsepower hour. It is an old-fashioned and imprecise way of comparing thermal efficiencies.
V. K. Desai started with the Semple engine, produced in the early 1950’s in St. Louis by Fred Semple and attempted to copy it. There were some issues about adjusting the cutoff in the prototypes and we think that has been resolved now. Then a Yarrow style boiler was made for burning wood. The Yarrow boiler is a good solid design. It involves a lot of welding, which is not a problem in a country with cheap abundant labor. I suggest that a separate burner and heat exchanger would be an improvement because then the flame would not be quenched on the cold water tubes, causing inefficient burning as well as creosote deposition. At least it is a start and this is something that will popularize steam power in Third World countries.