Sustainable
Technology and Energy for Vital Economic Needs
414 Triphammer Road, Ithaca, NY 14850 USA.
Email: jv19@cornell.edu
Website: www.virtualithaca.com/francis/stevenhomepage.html
In 2003 we
continued our work with wind power and solar cooking, and outreach, especially
in the form of new information about the STEVEN technologies added to our
website. Francis Vanek has taken up
full-time work as a lecturer in the Cornell engineering school and resigned his
post as director of the Foundation, but continues to contribute in a volunteer
capacity, as do Jaroslav, Wilda, and Steven Vanek, and board members Bob Parks
and Sarah Cummer. We hope you enjoy
this year's newsletter (our 13th annual) and welcome any
communications you may have.
Peace on earth,
The STEVEN Foundation
Topics:
1. Wind
2. New info on web
3. Contact with Engineers without Frontiers
4. Solar cooking
5. Other outreach
6. Editorial
In 2002 and 2003 we have focused on developing, under the STEVEN Foundation general objectives, a low-cost windmill technology. The technology should be not only low-cost but also sufficiently simple to permit a farmer or other user to construct and service the technology, and if necessary repair it.
We have chosen a designwhich could generate up to one or two kilowatts, using as much as possible parts or materials which are simple and easily obtainable. Two photo images below show the most recent stage of the development prototype: 1. a general overall view, and 2. its power generating elements.
http://www.virtualithaca.com/francis/Windmill2003pic1.jpg
Picture 1: General overview of the windmill.
The windmill resembles a Dutch windmill, with a four-blade rotor, 21 feet in diameter. The support tower is obtained from a standard telephone pole and thus can be varied up to some 50-foot height. Our prototype is over 25 feet tall and thus can be serviced by an extensible ladder. The pivoting assembly at the top is based on a 2 1/2 inch pipe, and within it a snugly fitting 2-inch pipe with a platform fitted at the top. On the platform we have two one-inch ball bearings holding a one-inch rod or axle. A steel plate is welded to one extremity of the axle: to the plate are attached 4 conduit pipes using 8 u-bolts, permitting to rotate and vary the pitch of the blades as desired. The blades or wings of the rotor are formed by sandwiching between the conduit pipes, and a section of a 2 x 4, pieces of a 1 foot by 2 inch light rigid foam insulation.
In later prototypes we have segmented the blades and positioned the extremities (outer sections) more perpendicular to the wind, in order to reduce the drag resulting from constant wind speed and variable circular speed of the various locations of the blades. This is shown in image #1.
Image #2 shows the detail of the power generating components. We found that for many reasons (cost, voltage regulation, etc.) the best solution for power generation is to use a car/truck alternator with plus-minus 1kilowatt capacity. The key problem with alternators is that they require high rpm’s. Thus, as shown in image #2, we proceed from a bicycle rim to a 2 inch pulley coupled with a 12 inch pulley and the 2.5 inch pulley of the alternator, thus obtaining 12 times 5 approximate acceleration. That is, the alternator rotates about sixty times faster than the rotor of the windmill. With approximate maximum rpm = 60, we thus reach an rpm = 3600, quite sufficient for the operation of the alternator. In practice, once the alternator is generating at over 2000 rpm, it creates a power load which will slow down the windmill to lesser speeds, but in excess of the required minimum. The transmission of rotation in the two-step arrangement is performed by standard alternator-type belts.
http://www.virtualithaca.com/francis/Windmill2003pic2.jpg
Picture 2: Closeup on the power drive system of
the windmill.
The greatest problem with windmills, especially those of larger rotor diameters, are high winds. The solution we are working on and are quite hopeful about is the simple possibility of “tuning” the tightness of the u-bolts holding the blades to a certain friction which permits--at a roughly prescribed high wind speed—the blades to flip to a position parallel to the wind. After the windstorm is over, it is easy to reset the blades to their most efficient position.
Our tests in high winds are quite promising, even though one prototype of the rotor was destroyed when only two blades were turned with the wind and the announced winds in the region were up to 70 mph. The other protection against high winds, equally significant, is the rigging (see image #1) using steel cables forming a pyramid-like body with a 4-foot pinnacle at the center: the cables connect to this center, and connect the extremities of the blades to form the bottom of the pyramid. In this way, inspired by the rigging of a sailboat, the entire rotor forms a rigid body which is quite robust.
The low-cost objective is also attained. Very approximately the cost, even including some reasonably estimated labor, is of the order of ten times less than commercial windmills of comparable rotor diameter. The cost per unit of power output we are not yet in a position to give.
In the future, following this writing in November 2003, we plan to test the windmill under winter conditions; and especially we will work on power generation and storage in car-type batteries. In 2004 we are informed that the NY legislature will vote on the possibility of selling wind power to the grid – a possibility now existing for photovoltaics. Of course we hope to try such power output utilization.
Up until
this year, our website included descriptions of the STEVEN technologies, but
not full manuals for construction, which instead were distributed in paper
form. This year we have uploaded
instruction manuals for three of the technologies, namely the solar oven, the
parabolic trough solar collector, and the solar icemaker. We hope that making the information more
easily available will facilitate transfer into the field, while at the same
time cutting down on postage cost and paper consumption. At the same time, we will continue to distribute
hard copies to those who do not have access to the on-line versions. We hope to upload more manuals in the
future. You can visit our website and
view the manuals at
http://www.virtualithaca.com/francis/stevenhomepage.html
Engineers
Without Frontiers, or EWF ( http://www.ewf-usa.org/
), is a new national organization in the US that is dedicated to applying
engineering skills to solving local problems.
During the 2002-2003 academic year, students at Cornell opened a chapter
of EWF, and this has provided a number of chances for interaction. In May, students in the group came out to
the Triphammer Road site to look over prototypes of the technologies that are
on display, and to learn about our approach to appropriate technology. Then in September, the EWF Cornell chapter
hosted a national conference of EWF members and other students from around the
US and also Canada who are interested in Appropriate Technology, so Francis
gave a talk about STEVEN, focusing in particular on our work in Mexico as an
example of the type of projects we have carried out in the past. He later gave the same talk to the EWF class
at Cornell, which is taught in Civil Engineering, and which gives students a
chance to earn academic credit for working on a humanitarian project. We expect to continue this collaboration in
the future.
http://www.virtualithaca.com/francis/P5060014.JPG
Francis
Vanek explaining the STEVEN technologies to visitors from EWF, May 2003.
Spring and summer 2003, when not raining in upstate New York (we had a very wet season) were again a good time for cooking with the S.T.E.V.E.N. solar oven. While we don’t have new menu suggestions to share, we want to assert once again that solar-cooked rice is the finest we know how to make. And unlike on the stove top, there is virtually no risk of overcooking or burning it. In good sun conditions it takes about an hour.
Our damp season did produce good crops of tomatoes; so once again we put the oven to use as a solar dryer. This works especially well with cherry tomatoes or small plum varieties. The oven box is used without reflectors, but set into full sun, so that there is heat for drying but not for cooking. Also, the glass lid is propped open slightly at one lower corner by inserting a small stick or a pebble, to allow escape of excess moisture but not much heat. Even so, the glass may become fogged with moisture as the tomatoes dry, and need wiping occasionally.
With good sun conditions, we dried 2 or 3 cookie sheets of the cut open tomatoes (cut side up) in about two days. Overnight, we were able to put the sheets into our kitchen oven which heats very mildly on a pilot light; without this advantage the drying would have lasted somewhat longer. For our patience, we have bags of the dried fruit which keep just on the pantry shelf, and can be used all winter long. If you like sun-dried tomatoes, it’s definitely worth doing.
During 2003 we received approximately 1 dozen inquiries by mail about the technologies, and 20-30 email inquiries. Along with general responses to such requests, we also worked more closely with individuals working in Belize, Honduras, and Ecuador, sending plans for the solar refrigerator to the first and plans for the solar oven to the other two. In the case of Ecuador, a group was able to make good use of the information on the website, which was encouraging for us as we seek to use the internet to continue our mission.
Over the course of the years that we have been writing our annual Newsletter, it seems that by some measures, the world has become a more precarious place: there appears to be more conflict and more environmental problems, and the plight of the very poorest people seems to be getting worse, or at least not getting markedly better. I have therefore wondered whether the new generation of engineers and scientists that is now studying at and graduating from our universities might become more fearful, and turn inward to a sheltered world of greater economic security. The experience of working with a number of students during this past year, however, has convinced me that this is not the case.
This past September, members of the Engineers Without Frontiers at Cornell organized and hosted a national conference of students interested in using engineering and science to help the disadvantaged and protect the environment in many different ways. Students came from campuses all around the country, and listened to keynote speakers from industry and government as well as each other presenting in seminars, and were able to exchange ideas about everything from appropriate technology to alternative energy and political activism. I had the chance myself to talk with some of these students and I was very impressed not only with their knowledge, but also with their commitment to the cause, and the insightful questions they were asking. Thinking back on my own undergraduate career in the Cornell engineering school in the later 1980s, I came away thinking that, if anything, the engineering students of today are becoming more politically engaged than they were back then.
The road to a world rid of poverty and inadequate environmental protection is still a long one. Here are some statistics I learned at the EWF conference: 1 billion people in the world do not have access to safe drinking water, and 800 million experience hunger on a regular basis. Clearly, the message I got from the conference was not that EWF as an organization was about to solve all of these problems. Rather, I was impressed by the resilience of “sustainable development” as a movement, to keep moving forward and to draw in new people and new ideas. The whole experience renewed my faith that, slowly but surely, we will turn the corner on world poverty. – Francis Vanek
Interested in learning more about the STEVEN technologies? Please write for manuals on water pumps, solar ovens, steam engines, and icemakers. STEVEN is a registered 501-c-3; donations are welcome.
