The S.T.E.V.E.N. Foundation Newsletter 1997

Solar Technology and Energy for Vital Economic Needs

S.T.E.V.E.N. Foundation,
Ithaca, New York, USA
Tel/Fax (607) 257 7109 
Greetings! it has been about a year since S.T.E.V.E.N. Foundation sent out a newsletter on its activities. Thus this edition will report on developments in the second half of 1996 and early 1997.


Our chief "missioner" during the past year was Steven Vanek. Working around other commitments, Steven was able to spend time in Haiti continuing the work begun there in January 1996 (see the '96 S.T.E.V.E.N. Newsletter). Earlier, he transferred S.T.E.V.E.N. technology during a mission with the SIFAT organization in Bolivia and Ecuador.

HAITI, NOV.- DEC. '96: S.T.E.V.E.N. Foundation had its first intensive contact with Haiti at a conference in Port-au-Prince in late January 1996, focussing both on solar technologies and on development through worker cooperatives. (see our '96 newsletter). A participant in that gathering, Sister Nina Joseph, works with a rural community in northern Haiti: she urged that we go there for a project of building and disseminating solar ovens. After some months of negotiations with co-sponsoring agencies in Haiti, Sr. Nina's persistence won out.

Steven Vanek spent 5 weeks in Haiti in November and December. The scope of the mission was two-fold: first, to transfer our technology of solar box ovens and build a first group of them; and second, to create appropriate structures for continuing the production, through a workers' cooperative, and also through a credit plan for their purchase by poorer Haitians. Vanek began with an educational component, teaching about the ovens before any were built, to members of the future coop and also to women of the community, who later proved very apt as they tracked the sun to bake a solar cake.

Construction of the ovens took place in three phases: a first demonstration oven, three for practice built by two-man teams, and then 22 more for sale, for a total of 26 ovens. Alongside the physical work, other sessions dealt with the formation of the cooperative, worker autonomy and the workers' "ownership" of their workplace and product. It is hoped that Prof. Orlando Sotomayor of Mayaguez, Puerto Rico, consultant on cooperatives to the project, will be able to visit Haiti during 1997 to reinforce this component of the training.

Rice and peas, a favorite Haitian dish, were cooked by sun as the work progressed. The mission concluded with a well-publicized public demonstration featuring a solar cake (baked even in partly cloudy weather). Next day, a final evaluation confronted issues yet to be resolved: costs vs. price vs. sufficient compensation for the coop worker-members; the desirability of a manual in Haitian kreyol, and eventually a cookbook; the need to enlarge the market for the ovens, and consolidate organization of the coop.

While S.T.E.V.E.N. Foundation stands ready to render additional assistance as requested, continuation of the project is in Haitian hands. The Office of the Prime Minister, our initial host in Haiti, has contracted with ITECA (Institut de Technologie et d'Animation), a non-governmental agency concerned with appropriate technology, agriculture, and community organizing, which gave both financial and personal support while Steven Vanek was in Haiti. We hope that these personal and organizational resources will provide for a flowering of solar ovens in the Caribbean sun.

BOLIVIA and ECUADOR, JULY - AUGUST '96: With Steven Vanek as one of the team, our colleagues from SIFAT (Servants in Faith and Technology) went on mission in rural areas of these two South American countries, giving a month of Christian formation and technology training to a group first in Patacamaya (near La Paz on the Bolivian altiplano), then another at Caliata in the highlands of central Ecuador. S.T.E.V.E.N. solar ovens, and other solar and simple wood-burning technologies were constructed in both locations. Clear weather in Patacamaya made possible some effective solar results. In Caliata, however, central Ecuador in August proved too cloudy for use of solar ovens.


HOME POWER magazine, June-July 1996 (Issue #53, Pp. 20-23) contains an article on "A Solar Ammonia Absorption Icemaker" co-authored by Jaroslav Vanek, Mark "Moth" Green, and Steven Vanek. Its text, photos and diagrams give probably the clearest treatment to date of our work toward a solar refrigerator. We urge those interested to find a copy of the journal, with its clear color photos and diagrams. As second best, we can send a black/white copy upon request.

New PROSPECTUS: Most of you have received a prospectus on "The S.T.E.V.E.N. Technologies" that goes back to 1991. After six years of further work, it was high time for an update, which we issued in March 1997. Anyone with a serious interest in our technologies--solar collector and tracker, water pumps, steam engines and applications, box oven/cooker and refrigerator--should write us for a copy. A $1. donation (or a few postage stamps) with your request will help us with postage: but if that poses any problem, we will be delighted to send the prospectus to you gratis. Be our guest!


Since Professor Vanek retired from teaching at Cornell, there has been more time for further researching of S.T.E.V.E.N. technologies. Two works in progress ought to be reported on, hoping for final answers in the next newsletter.

First there is the question of efficiency of our steam engine systems based on our parabolic trough collector. Reading the excellent study A Golden Thread (Ken Butti and John Perlin, 1980) on history of solar technology, we found that the perforrnance of several simple solar steam engines indicated far higher levels of thermodynamic efficiency than our own. More concretely, as a rough relationship the output of one horsepower of mechanical power corresponds in those experiences to about 200 square feet--or some twenty square meters--of reflector aperture to full sun. Our basic collector measures some 100 sq. ft., but our power outputs have been measured on the order of several times less than one-half horsepower. In fact if we could obtain anything like that amount, say 300 watts, from out collector we could outcompete per dollar spent even the most optimistic estimates for photovoltaics.

Consequently there is a challenging question of why our results are so poor--or alternatively, are the reports in the quoted study for some reason incorrect? Our first work in progress deals with the practical aspects of this question. So far we have constructed a much smaller engine than those we have previously used, to be installed directly at the top of the solar boiler on the collector. This will permit us to study three potential sources of inefficiency: 1. our engine thus far was too large, and 2. used in equilibrium far too low pressures; 3. a lot of eneergy/power was lost on long and imperfectly insulated thin steam ducts. We hope to have more to say in a later newsletter.

Second, we were asked to advise some friends from the Peruvian Andes about a project of pumping water from a valley up to a village some 200 feet above, using the power of the water flow through purchased ram-pumps. We found that the rams are not only quite expensive, but the technology may be too advanced in design for rural villages with poor access Consequently we are exploring the possibility of supplying a S.T.E.V.E.N. technology which could be simple and produceable locally, at least partly from locally available and/or recycled materials. The first solution, already tried in prototype, is based on a water turbine propelling a positive displacement pump. But our madel thus far is technically quite inefficient and our reaseach is moving on further in this direction, hoping for better results and also exploring other avenues. Again, we have no final results or answers and hope to have some bext time.

Other recent advances in the various S.T.E.V.E.N. technologies are discussed in the new edition of our prospectus. Especially interesting are the new alternative design of a "rocking-piston" steam engine (nicknamed the "penguin" engine from its motion); also the advance to larger and more powerful solar box oven/cookers, and progress on our icemaker-reefrigerator (as published in Home Power). We urge anyone interested to contact us for a copy of the prospectus.


In the last few years, our S.T.E.V.E.N design of solar box oven/cookers have been markedly improved over the original model. With 3 different sizes and many refinements, we now achieve higher temperatures to cook or bake a broader range of foods, and can use the cooker with less-than-perfect solar conditions. Anyone who had our original manual for biulding the solar oven is entitled to an upgrade. Anyone else who would like to enjoy solar cooking, please contact us.

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