S.T.E.V.E.N.
Website: http://www.virtualithaca.com/francis/stevenhomepage.html
NEWSLETTER 2007
NEW
RESEARCH
Our technical research and activity this year consisted of three broad areas – all of which should be called work in progress. We cannot speak of any complete achievements, except perhaps for the important fact that Francis Vanek’s textbook (“Energy Systems Engineering: Evaluation and Implementation”) was completed and went to print with McGraw-Hill publishers. It was not a direct project of the Foundation, but we offered some inspiration and minor services in that connection, since the book deals with several aspects of renewable energy.
The first area of our technical work concerns the low cost [equatorial] solar house, as described in chapter 23 of J. Vanek, THE UNIFIED THEORY OF SOCIAL SYSTEMS [accessible online: see http://hdl.handle.net/1813/642 ] We were able to construct a 10x16 foot F=40’’ parabola, representing one-third of the roof and solar collector of the solar house. Unfortunately, we completed this task too late in the season to permit actual solar testing of its performance, for the simple reason that in our test-ground high trees prevent insolation after the end of September.
The second area of work, related to the first, concerns the
small steam engine to be used with a roof-parabola-collector covering the full
roof of a house, 30 feet long. We
abandoned the design of the early years of our solar work in favor of a more
efficient and inexpensive transformation of a small four-stroke combustion engine.
Such a transformed steam engine can be easily produced from a small lawnmower
engine, with a capacity of two or three HP, or larger if there is enough steam.
We have produced two solutions [one of 3 HP, used, costing $20.;
the other new, 2 HP, costing $99.], both
working very well with compressed air.
We hope to test the performance once our ten-foot parabola can be
exposed to the sun. Of course it is expected that the power of such transformed
engines will be far less than the power of the original combustion engines. But
this is the result of a limitation of solar steam availability.
The third activity, in an even more preliminary state of R + D, concerns a very low cost windmill. Some years ago we abandoned the project of a low-cost conventional mill, for the reason that with high winds such mills tend to disintegrate, unlike the high-cost mills we see springing up around the country, costing millions of dollars. We are aiming here at greater accessibility, wind exposure and easy safety devices to deal with high wind speeds.
Anyone interested in this alternative windmill development may wish to communicate that interest to us (best by e-mail). As work progresses again in the spring, it may be possible to report an update.
ONGOING
TECHNOLOGIES
Of the many technologies presented in the S.T.E.V.E.N. prospectus, two have provoked continuing interest: our solar oven/cooker, and the S.T.E.V.E.N. icemaker. Our oven, a box design heated by reflective panels attached to all four sides, resembles many other models: ours has the advantage of being inexpensive to build in most parts of the world, while nonetheless generating high enough temperatures (with good sun) for many cooking and baking uses. Our reflectors are powered by aluminized Mylar plastic, of which we have a supply from the 3-M Corporation.
We are continuing to collaborate in promoting solar ovens with “Engineers for a Sustainable World”, or ESW, at Cornell, where Francis teaches a service learning course to undergraduate engineers, some of whom are studying solar cooking. The ESW students’ primary collaborator is now a Nicaraguan NGO called “Grupo Fenix” that promotes solar cooking, with S.T.E.V.E.N. in an advisory role about the design of the ovens. With our input, and under the leadership of Tim Bond, laboratory manager of the Winter Laboratory at Cornell, the students have also developed a “solar simulator” using high-power lighting that allows continuous testing of solar oven prototypes at any time of day or night in a protected indoor setting.
Once again, we announce that we can supply Mylar in moderate quantities, for building one or a few cookers. Please contact us for price and shipping details, preferably by e-mail to: jv19@cornell.edu or by telephone: 607 257 7109.
For a copy of our detailed and illustrated instructions on building the S.T.E.V.E.N. solar cooker, you have only to contact us or visit our website to download.
The S.T.E.V.E.N. solar icemaker was described in an article in HOME POWER magazine, June 1996. We are amazed and pleased that, thanks to the internet, we are still receiving responses to that article, 11 years later. [See: www.homepower.com then archive for Issue 53, June 1996, “A Solar Ammonia Absorption Icemaker.”]
We had started, two years ago now, to build a new design of a permanently sealed icemaker system that would optimize elements of the systems already tested, as well as using a ground-coupled heat exchanger to condense ammonia from the generator. Steven Vanek is hoping to make additional progress on this icemaker, but a number of other projects have kept him busy. He has the evaporator, generator, and condenser tanks ready and needs to finish other elements of the system such as the solar collector, as well as performing leak testing. He is hoping to pursue additional work on the icemaker this summer, when testing could occur.