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Natural Science Forum / Physics / General Physics / July 2008A new solar technology could increase the power generated by solar panels tenfold, a team of scientists show.
http://news.bbc.co.uk/go/rss/-/1/hi/technology/7501476.stm --Mike Jr > http://news.bbc.co.uk/go/rss/-/1/hi/technology/7501476.stm > > --Mike Jr And: http://news.cnet.com/8301-11128_3-9988923-54.html?hhTest=1 > >http://news.bbc.co.uk/go/rss/-/1/hi/technology/7501476.stm > > > --Mike Jr > > And:http://news.cnet.com/8301-11128_3-9988923-54.html?hhTest=1 I monitor the BBC to keep an eye on their biases. It is ironic that I refer to them when they get something right. But enough about the messenger. This invention strikes me as potentially very important, even pivotal. I will be following up on it as more information becomes available. --Mike Jr > > >http://news.bbc.co.uk/go/rss/-/1/hi/technology/7501476.stm > > > > > --Mike Jr > > > > And:http://news.cnet.com/8301-11128_3-9988923-54.html?hhTest=1 > I monitor the BBC to keep an eye on their biases. It is ironic that I > refer to them when they get something right. But enough about the > messenger. > This invention strikes me as potentially very important, even pivotal. > I will be following up on it as more information becomes available. A south facing vertical plate at 35 degrees north latitude receives 57% of the incident energy at noon and it goes down from there. Yet another niche device.  SignatureJim Pennino Remove .spam.sux to reply. On Jul 12, 12:45 pm, j...@specsol.spam.sux.com wrote: > > > >http://news.bbc.co.uk/go/rss/-/1/hi/technology/7501476.stm > [quoted text clipped - 16 lines] > > Remove .spam.sux to reply. What is the efficiency of that solar cell? Maybe a high-end 24% efficient silicon wafer? Or maybe a 19.5% efficient solar cell based on copper indium gallium selenide thin film, aka CIGS? It is not a 40.7% efficient triple-junction solar cell because these are designed to work with concentrated light, specifically the wattage of 240 suns. How are you going to concentrate that much wattage? Ah, now maybe you start to see the advantage of high-efficiency organic solar concentrators. “OSCs [organic solar concentrators] consist of a thin film of organic dyes deposited on high-refractive-index glass substrates. The dyes absorb incident solar radiation and reemit it at a lower energy. Approximately 80% of the reemitted photons are trapped within the waveguide by total internal reflection for ultimate collection by a PV device mounted on the substrate edges.” From Fig. 1, Physical configuration of OSCs, in "High-Efficiency Organic Solar Concentrators for Photovoltaics", Michael J. Currie, et al., Science 321, 226 (2008). The ratio of the area of the concentrator to the area of the PV cell is the geometric gain G, also known as the geometric concentration factor. The paper states that with G=630, a projected maximum flux gain of 46 +/- 15 is probable. And this will be cheap. --Mike Jr > On Jul 12, 12:45 pm, j...@specsol.spam.sux.com wrote: > > > > >http://news.bbc.co.uk/go/rss/-/1/hi/technology/7501476.stm [quoted text clipped - 17 lines] > > > > Remove .spam.sux to reply. > What is the efficiency of that solar cell? Maybe a high-end 24% > efficient silicon wafer? Or maybe a 19.5% efficient solar cell based > on copper indium gallium selenide thin film, aka CIGS? > It is not a 40.7% efficient triple-junction solar cell because these > are designed to work with concentrated light, specifically the wattage > of 240 suns. > How are you going to concentrate that much wattage? > Ah, now maybe you start to see the advantage of high-efficiency > organic solar concentrators. > ?OSCs [organic solar concentrators] consist of a thin film of organic > dyes deposited on high-refractive-index glass substrates. The dyes [quoted text clipped - 5 lines] > for Photovoltaics", Michael J. Currie, et al., Science 321, 226 > (2008). > The ratio of the area of the concentrator to the area of the PV cell > is the geometric gain G, also known as the geometric concentration > factor. The paper states that with G=630, a projected maximum flux > gain of 46 +/- 15 is probable. > And this will be cheap. All wonderfull and has nothing to do with what I said. SignatureJim Pennino Remove .spam.sux to reply. On Jul 12, 8:05 pm, j...@specsol.spam.sux.com wrote: > > On Jul 12, 12:45 pm, j...@specsol.spam.sux.com wrote: > > > > > >http://news.bbc.co.uk/go/rss/-/1/hi/technology/7501476.stm [quoted text clipped - 47 lines] > > Remove .spam.sux to reply. I guess we will just have to agree that we are at cross purposes and get on with our lives. --Mike Jr > On Jul 12, 8:05 pm, j...@specsol.spam.sux.com wrote: > > > On Jul 12, 12:45 pm, j...@specsol.spam.sux.com wrote: [quoted text clipped - 48 lines] > > > > Remove .spam.sux to reply. > I guess we will just have to agree that we are at cross purposes and > get on with our lives. > --Mike Jr I have NO idea what the hell you are talking about. I was referring to the fact that simple trigonometry shows a vertical plate only intercepts a fraction of the available incident solar energy and if you are located at 35 degrees north latitude, that fraction is 57% at best. SignatureJim Pennino Remove .spam.sux to reply. On Jul 12, 10:35 pm, j...@specsol.spam.sux.com wrote: > > On Jul 12, 8:05 pm, j...@specsol.spam.sux.com wrote: > > > > On Jul 12, 12:45 pm, j...@specsol.spam.sux.com wrote: [quoted text clipped - 63 lines] > > Remove .spam.sux to reply. Not so. The advantage of active concentrators (luminescent systems) is that the absorption of the incident light is not dependent on the angle, the system can operate at all incidence angles. Take a look at http://www.ee.ucla.edu/~photon/pubs/ey1990sem2123.pdf Scroll on down to section 3. --Mike Jr. > On Jul 12, 10:35 pm, j...@specsol.spam.sux.com wrote: > > > On Jul 12, 8:05 pm, j...@specsol.spam.sux.com wrote: [quoted text clipped - 64 lines] > > > > Remove .spam.sux to reply. > Not so. The advantage of active concentrators (luminescent systems) > is that the absorption of the incident light is not dependent on the > angle, the system can operate at all incidence angles. > Take a look at http://www.ee.ucla.edu/~photon/pubs/ey1990sem2123.pdf > Scroll on down to section 3. > --Mike Jr. Yes so. The amount of incident solar energy on a flat surface per unit area is equal to the available energy per unit area times the sine of the angle of the incident energy. If the angle is 90 degrees you get 100%. If the angle is 30 degrees you get 50%. It is simple, basic trigonometery and there is absolutely nothing you can do about it. Why do you think fixed collectors are mounted at an angle equal to the latitude? You can, for example, make a parabolic concentrator which concentrates all the energy at the focal point. However, the amount of energy available to be concentrated will be equal to that of a flat cicular plate who's diameter is equal to the parabola diameter times the sine of the angle between the parabola axis minus 90 degrees and the incident light. SignatureJim Pennino Remove .spam.sux to reply. On Jul 13, 12:15 am, j...@specsol.spam.sux.com wrote: > > On Jul 12, 10:35 pm, j...@specsol.spam.sux.com wrote: > > > > On Jul 12, 8:05 pm, j...@specsol.spam.sux.com wrote: [quoted text clipped - 89 lines] > You can, for example, make a parabolic concentrator which concentrates > all the energy at the focal point. Jim, Didn't you read my reference? The optimal reflector is not a flat plate. For a fluorescent collector, try a series of V-shapped collectors. If you are really interested, take a look at "Conversion with Fluorescent Collectors", by A. Goetzberger, in Applied Physics A: Materials Science & Processing, 1977. Look at page 128, Figure 8 "Optimum shape of collector is a triangle with right angle at apex. Two sides are mirror coated. Concentrated energy is obtained at hypotenuse with length I. This figure also shows how large areas can be covered continuously with collectors". Fluorescent collectors work with diffuse as well as direct light so they will concentrate light even on overcast days. BTW, the correct response is "thank you", not "thank THE HELL you". --Mike Jr > However, the amount of energy available to be concentrated will be equal > to that of a flat cicular plate who's diameter is equal to the parabola [quoted text clipped - 5 lines] > > Remove .spam.sux to reply. > On Jul 13, 12:15 am, j...@specsol.spam.sux.com wrote: > > The amount of incident solar energy on a flat surface per unit area is > > equal to the available energy per unit area times the sine of the angle [quoted text clipped - 12 lines] > > You can, for example, make a parabolic concentrator which concentrates > > all the energy at the focal point. > Jim, > Didn't you read my reference? > The optimal reflector is not a flat plate. For a fluorescent > collector, try a series of V-shapped collectors. Totally irrelevant. The total energy available to any shape reflector is equal to that of a flat plate who's area equals the profile area of the reflector. That energy is further reduced by the sine of the angle between the normal to the equivelant flat plate minus the angle of the incident energy. All a reflector does, no matter what shape it is, is concentrate the available energy into a smaller area. The total energy (neglecting reflection losses) doesn't change. This is elementry, Junior High School trigonometry. SignatureJim Pennino Remove .spam.sux to reply. On Jul 13, 10:05 pm, j...@specsol.spam.sux.com wrote: > > On Jul 13, 12:15 am, j...@specsol.spam.sux.com wrote: > > > The amount of incident solar energy on a flat surface per unit area is [quoted text clipped - 32 lines] > > This is elementry, Junior High School trigonometry. Sigh. Read the references. > -- > Jim Pennino > > Remove .spam.sux to reply. > On Jul 13, 10:05 pm, j...@specsol.spam.sux.com wrote: > > > On Jul 13, 12:15 am, j...@specsol.spam.sux.com wrote: [quoted text clipped - 33 lines] > > > > This is elementry, Junior High School trigonometry. > Sigh. Read the references. Sigh my a.s; you just don't understand basic trigonometery and geometry. SignatureJim Pennino Remove .spam.sux to reply. |
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