A few years ago we tested a Fresnel lens concentrating system for a client. They didn't have their tracking right and burned a trench across their circuit boards with the focused energy. Focusing and concentrating are really two different design problems where focusing require much better tolerancing of everything. I have a solar oven to heat up my beans that has flat sides - easily boils and chars food but requires very little effort to focus. The 400F system used curved mirrors that required precise manufacture to be properly efficient without tracking.
Tracking is quite expensive, so you have to make a lot of power to get payback. You might think this concentrating solar stuff is a no-brainer, but it is not all that easy in practice, the fact that the sun moves & where it moves is a large complication when you are trying to focus it. There is a start up called Semprius that has gotten 30% PV efficiency with little concentrating lenses over individual semi conductor cells. There are a multitude of these on a panel. I am not aware of anything with better performance on the horizon. The problem with solar thermal, efficient as it is, the energy is not much use if you don't need hot water or air. It takes a lot of family to get much use of solar thermal. The hardware for thermal energy is less reliable and more complicated than electricity and solar generated electricity. For instance, my wife and I, in our 1300sqft house cannot justify a solar thermal system, instead we spent about 25$ insulating our resistance heated tank and hot water piping. The added complication, cost and potential for unreliability is likewise difficult to justify for thermal in combination with PV. You get some hot water, but the savings add up very slowly, and you improve the efficiency of the PV a bit. If you run the numbers it is often better to simply put up one more PV panel. This can be complicated by whether the topology of the system supports adding only one panel and not a whole string and an inverter upgrade. Back to the Ford car, good panels in the roof, making 500W is not a terrible idea and maybe also good marketing. Just skip the carport business. On Fri, Jan 3, 2014 at 4:28 PM, Lee Hart <[email protected]> wrote: > If it's a student project, it can be kind of goofy and impractical. It > should also a good learning experience (and fun). :-) > > The big fresnel lens is going to require that the car be parked precisely > under the focal point. It also doesn't take into account that the sun > moves. So... > > How about putting a motorized mirror on a pole? A camera looks for the > car, spots its solar panel, and steers the mirror to direct the sun on it. > Now you get more power. > > This also avoids burning a hole in mother-in-law's convertible top when > she comes over for dinner, or setting fire to the cat that happens to walk > across the driveway. > > Maybe it could even eke out a little more power at night, from the full > moon or a street light. > -- > We live in a society exquisitely dependent on science and technology, > in which hardly anyone knows anything about science and technology. > -- Carl Sagan > -- > Lee Hart -- See my Xmas projects at www.sunrise-ev.com/projects.htm > > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/ > group/NEDRA) > > -- Put this question to yourself: should I use everyone else to attain happiness, or should I help others gain happiness? *Dalai Lama * Tell me what it is you plan to do With your one wild and precious life? Mary Oliver, "The summer day." To invent, you need a good imagination and a pile of junk. Thomas A. Edison<http://www.brainyquote.com/quotes/quotes/t/thomasaed125362.html> A public-opinion poll is no substitute for thought. *Warren Buffet* Michael E. Ross (919) 550-2430 Land (919) 576-0824 <https://www.google.com/voice/b/0?pli=1#phones> Google Phone (919) 631-1451 Cell (919) 513-0418 Desk [email protected] <[email protected]> -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140103/f77c4cb8/attachment.htm> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
