Alternative Energy

Alternative Energy

Alternative energy news, and information about renewable energy technologies.

Jun 18

New Generation of Solar Devices with Trapped Sunlight

Posted in Energy Inventions | Future Technology | Solar Power

Trapping Sunlight What a wonderful age we are living in! We hear about so many possibilities in the field of alternative energy. Scientists all over the world are thinking about alternatives to fossil fuel. On every scale be it large or small progress is being made. Here the researchers are inspired by the Greek legend Dionysius’ ear. Dionysius erected a cave. It was shaped like an ellipse. Dionysius’ purpose was to hear the words whispered by a prisoner in one of the foci of the cave. Some of the present day science day museums are following the same features where two people standing the extreme ends of a room can hear each other’s whisper. This feature motivated physicists Roberto De Luca and Aniello Fedullo, both of the University of Salerno in Italy, to design sunlight traps. They are using two elliptical mirrors, with one collecting sunlight and another (they named it zozzaroid) focusing sunlight back to the vertex of previous one and into the blackbody. Here they are using mirror for steam generation.

Their study was published in the European Journal of Physics. They have duplicated acoustical Dionysius’ ear for their sunlight trapping system. They have arranged two parabolic mirrors face-to-face. Sunlight first falls on the larger mirror and reflects to the smaller mirror placed a short distance away. Then the light from the smaller mirror reflects back. This reflected light is focused into the vertex of the larger mirror. This way they have locked up the sunlight into this small region. Now this light can be used for various purposes. The sunlight is stored in a blackbody, which consists of a cavity with perfectly reflecting inner walls.

De Luca shares his views, “Through a sunlight trap system, solar radiation is first concentrated in a small region of space and then sent into a blackbody, where it can be stored (not for an arbitrary long time, though) for a variety of uses. For example, after having trapped sunlight in a cavity with perfectly reflecting inner walls, what we call a blackbody, one can think of heating water enclosed in a container placed inside the cavity itself. Other uses of this concept are also conceivable.”

This idea was first conceived by Paolantonio Zozzaro, a high school physics professor from the Province of Salerno. Zozzaro often wondered about the shape of the smaller mirror that can reflect all incident light rays to the vertex of the larger mirror. De Luca and Fedullo carried forward from this point. They investigated the feasibility of such a perfect sunlight trapping system, which was first envisioned by Zozzaro. With help of their computations, De Luca and Fedullo reached to the conclusion that the smaller mirror should have a specific elliptic or hyperbolic profile akin to Dionysius’ ear. Out of respect for Zozzaro they call this secondary mirror a “zozzaroid.” Their design focuses sunlight very effectively, so that it can be transferred to a blackbody with a rather small hole.

The scientists anticipate that the new sunlight collector could be useful for a variety of alternative energy applications. De Luca has scrutinized the likelihood of using the device to produce steam. The advantage of producing such steam is that it will be prepared without the need for a convection fluid. In the hollow cavity of the blackbody, he added a metal container into which water is pumped. In the course of conduction, heat is transported from the metal container to the water, which is transformed into superheated steam. Now this steam can be utilized for various purposes such as power generation. One of the valuable applications of this steam generation is that such a system might be able to transform sea water into drinking water using only solar energy.

  • Homz Umrigar

    This is good news for those cloudy days!

  • Peter C. Frank

    I saw a show on the Science Channel where light from the sun was passed through a layer that focused it and delivered 8x the energy to the solar cells, resulting in the same increase in energy output from them as well — astounding, amazing, and wunderbar!

  • John Boston

    @Peter: Was the layer like a big magnifying glass? Makes sense.

  • Brian Dunlevy

    Just goes to show that the technology is out there.
    the govt. simply doesn’t want us to use it.

  • Jeremy Eckert

    No no. Not the government. Corporations, don’t get confused.

  • Doug Quayle

    There is a difference between the two? I thought it was still Washington D.C. Inc.

    Oh… right… that was all supposed to “change”, right? Si Se Puede, and all that jazz.

  • Francois

    “Just goes to show that the technology is out there.”

    It is out there; however, the government could have done more by allocating much more of the so-called stimulus package to green energies than it did.

    That said, there is the nasty little problem of moving from proof of concept to mass applications. As any engineer will tell you, (as my brother is always fond to sardonically reminds me…can you tell he is an engineer? 😀 ) history is replete with awesome ideas that couldn’t make it to mass production for reasons much more mundane than vast conspiracies.

    Of course, that is no reason not to invest more in green R&D. It’s not as if we had the luxury to do otherwise.

  • Uncle B

    We already have the solar technologies to survive without other energy! The missing piece, the super-insulations to build our survival earth-arks from! Many molded plastics and some new space-age insulations fill the bill but are kept from us for various reasons, the most likely being shyster greed and patent controls! We pay through the nose for inefficient refrigeration units right now, and the larger sin of the patent holders is increased foreign oil consumption and a dying economy. The shysters are hurting our America! Imagine off-grid self-sufficiency. Working only occasionally, only for spare cash! Early and comfortable retirement! Second careers! Back to school! Spending time with family! All possible with today’s technologies, and some off-gridders have proven it. They are living examples of the full-time artists, beer-brewers, wine-makers, whatever their hearts desire! Beware the “Professional Architect” he has a huge kick-back scheme for unnecessary products behind him, and an education in capitalistic debauchery at heart! He is a liar to promote his own mythical importance, a maintainer and enforcer of antiquated and useless civil codes deigned to support the status quo construction industry, his prime employer! The Scientist, building habitation for humanity, the “Earth Arcs” for example, is differently motivated, and can be realistic without pressure to merchandise “McMansion” follies and foist them like cheap shysters on the poor trusting American consumer! Take “Planned obsolescence” out of the average American built car, and we have a re-buildable, repairable machine, no requiring expensive scrapping and reforming processes every six years! Change the epoxy curing rates in the paints and rubbers alone and add years of life to what we have already paid for! Stop screwing folks with engines designed to die! Why was the Chrysler Co.s flat-head six from the 50’s,60’s famous? Many rebuilds from each casting, thats why! Rebuild ability and net oil savings, thats why! Where did the vulture capitalists and accountants get into engine design, body building, and chassis construction? when Americans were diverted from basic quality by style and luxury, model status over model quality and longevity! The advertisers and the bookkeepers have had their way with the common folk! and now we don’t even have a car industry here and have turned to Asia for practical models! Same with housing, McMansions over the practical realities of our lives and pocket-books What happened?

  • greg glessner

    Believe it or not I’ve been touting and trying to get some help with this very concept/actually real concept, since 93. there is a concern with what uncle b said-however once we dumb humans realize our goals, we will build longevity into our products again. So I agree,-make things that are safe and extremely practical, hence- green! our country has had an agenda with its oil, but when gas went to 435 per gal. that was actually a cry for help. So when everyone is ready for some practical help with this solar steam field, feel free to look me up. I have a lot to bring to the table.

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