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Power Technology

Jackie Chan Discs Help Boost Solar Panel Efficiency 194

wbr1 writes Apparently the pit pattern on a blu-ray disk is great at helping trap photons, rather than reflecting them. Applying this pattern to the glass in a solar panel can boost efficiency by 22%. Researchers at Northwestern tested this system with Jackie Chan discs. From the article: "To increase the efficiency of a solar panel by 22%, the researchers at Northwestern bought a copy of Police Story 3: Supercop on Blu-ray; removed the top plastic layer, exposing the recording medium beneath; cast a mold of the quasi-random pattern; and then used the mold to create a photovoltaic cell with the same pattern....The end result is a solar panel that has a quantum efficiency of around 40% — up about 22% from the non-patterned solar panel."
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Jackie Chan Discs Help Boost Solar Panel Efficiency

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  • Copyright? (Score:5, Funny)

    by BronsCon ( 927697 ) <social@bronstrup.com> on Wednesday November 26, 2014 @04:19PM (#48469937) Journal
    Cue copyright infringement suit in 3..2..1...
    • Okay, now that I got my somehow-relevant first post...

      This is a really cool development and I hope they have very-near-future plans to develop this further and commercialize it. Every little bit of efficiency we can squeeze out of solar cells makes them practical for a wider variety of uses.
      • by pollarda ( 632730 ) on Wednesday November 26, 2014 @06:21PM (#48470727)
        If they can do this with SuperCop, just imagine what sort of efficencies they could get by using an AC/DC album! Also by using AC/DC as the base pattern it might allow them to create native AC and skip the use of a DC->AC power inverter.
        • by TWX ( 665546 )
          I vote we use the entire discographies of Tiffany, Yoko Ono, and Hansen. And by entire discographies, I mean all of the discs minted.

          I don't mind listening to AC/DC from time to time, and power conversion aside, there are much worse acts whose work could be destroyed^H^H^H^H^H^H^H^H^Hused for this.
        • If they can do this with SuperCop, just imagine what sort of efficencies they could get by using an AC/DC album! Also by using AC/DC as the base pattern it might allow them to create native AC and skip the use of a DC->AC power inverter.

          You better be careful of which album you try. "High Voltage" and "Powerage" will probably get you the best results. "Back in Black", may just give you the opposite outcome you're looking for. And good luck if you use "T.N.T", "Highway to Hell", or "Ball Breaker". It might be safer to stick with a U2 or even an Enya album.

        • by mjwx ( 966435 ) on Wednesday November 26, 2014 @07:34PM (#48471177)

          If they can do this with SuperCop, just imagine what sort of efficencies they could get by using an AC/DC album! Also by using AC/DC as the base pattern it might allow them to create native AC and skip the use of a DC->AC power inverter.

          AC/DC is bad, the last thing you want is for your solar panels to be... THUNDERSTRUCK.

    • Can you claim copyright infringement for a derivative work? Entitled to royalties at a minimum right?

      • It's not a derivative work, though; at the very least the mold they made of the disc is a direct (even if inverse) copy that can be used to make other direct (and not inverse) copies.
      • Of course derived works infringe copyright. Why don't you simply read the aprobriated law?
        How ever in thise case we don't have derived work ... hint: the law defines what a derived work is.

    • northwestern law school can help out there.

  • by Anonymous Coward on Wednesday November 26, 2014 @04:20PM (#48469943)
    Imagine what it could be with a Chuck Norris movie!!!
  • If this can be mass produced quickly by the likes of Solar City, imagine the gains! This could mean independence from fossil fuels in the next 2 years. Very exciting stuff.

    • by ogdenk ( 712300 )

      A.) This doesn't mean a solar car is practical.

      B.) For much cleaner energy with much higher output, we already have a better option than coal that's been proven effective and safe as long as you don't build them on beaches in earthquake zones. Nuclear power pound for pound is much cleaner and much more efficient than coal and doesn't emit as much harmful radiation directly into the environment like coal. And with fast breeder reactors, the waste can be reused as fuel. And pebble bed reactors are nearly

      • Re:Mass produce! (Score:5, Interesting)

        by spiritplumber ( 1944222 ) on Wednesday November 26, 2014 @05:23PM (#48470361) Homepage
        I've had a solar bike for about six months, and it works fine for my needs (mostly grocery shopping and laundry). Now that it's winter, I have to occasionally charge it. It cost about $350 to put together.
        • Re:Mass produce! (Score:5, Informative)

          by spiritplumber ( 1944222 ) on Wednesday November 26, 2014 @06:18PM (#48470717) Homepage
          Here's the picture: http://f3.to/quickgal/14049339... [f3.to]
        • by ogdenk ( 712300 )

          While very cool, I live in rural SC. Distances are pretty extreme. I want one to play with, but I couldn't use an electric vehicle as serious transportation until battery efficiency increases quite a bit more. A Tesla would ALMOST be practical but would cost a lot.

          I'm very pro-electric but I don't see solar cars being a reality for anyone outside of a well-populated urban bubble.

          Electric engines bring some interesting benefits compared to gas engines of comparable size and can keep up with and often exce

      • Let's put some nuclear reactors in your backyard!

      • a) true but more practical than now if it can be covered in enough solar to add charge to its batteries during it being driven

        b) yes, but a practical nucleur car, i doubt it - the military would be all over it if it could be done practically.

        c) sci-fi solution at the moment, by the time its possible all cars will probably be autonomous

        Solar is definitely more practical than nucleur at the moment.
    • Solar panels = Small percentage of power production
      Small percentage * 1.22 = Small percentage, just a shade higher.

      Its not a game changer. Its just a nice development.

      • Solar panels = Small percentage of power production Small percentage * 1.22 = Small percentage, just a shade higher.

        Its not a game changer. Its just a nice development.

        Efficiency improvements, mass production, and making coal internalize the cost of CO2 emissions will eventually make photovoltaics more cost-effective than coal. Once that point is reached, solar will take over a large percentage of electricity production. This might not be the improvement that puts it over the top, but I think your dismissive analysis is a little too simplistic.

      • Electricity is fungible - IE most people don't care where it comes from, so any one kWh is equivalent to any other.

        Consider if Biodiesel is $3.50 and fossil diesel is $3. You're going to sell vastly more diesel than biodiesel. Make Biodiesel 22% cheaper and it's now $2.73. The situation will reverse practically overnight. More realistically what will happen is that investments in BD would languish until diesel hit $3.50, then plants would be built right and left, pushing down the price of both, but as p

  • Why wast a reasonably good Blu-ray movie when I'm sure there are plenty of bad ones looking for a use?

    I don't know if supercop was a good movie or not but it had to have been better than a number [imdb.com] of movies [imdb.com].
  • BLUE ray (Score:5, Insightful)

    by Spy Handler ( 822350 ) on Wednesday November 26, 2014 @04:33PM (#48470039) Homepage Journal

    The pits on a blu ray disc are optimized for reading with a blue laser. Sun's output have more energy at the other end (red spectrum). I'm thinking they might get even better efficiency if they tried a disc pitting pattern that was meant for reading with a red laser.

    • Now that they have a proof of concept, it is an obvious thing for researchers to try different pit sizes and patterns in order to optimize the efficiency. One thing they probably haven't checked yet is the effect of Sun angle. Most solar panels are on a fixed mounting. So the Sun lights them from different angles during the day. Therefore any patterning will have a different apparent pit spacing. I think there is a lot more to learn about this effect, but even small efficiency gains have dramatic effec

      • Re:BLUE ray (Score:5, Insightful)

        by pavon ( 30274 ) on Wednesday November 26, 2014 @05:23PM (#48470359)

        Now that they have a proof of concept, it is an obvious thing for researchers to try different pit sizes and patterns in order to optimize the efficiency

        Actually, that already happened. As the abstract of the paper notes, previous research has already identified how to theoretically optimize patterns, but arbitrary patterns require expensive photo lithography equipment to create. This research shows that an existing inexpensive mass production technique generates results that are almost as good as the optimized patterns, but not quite as good because the spacing of the pits is a bit too periodic (especially across tracks rather than along them).

        • Re: (Score:2, Insightful)

          by Anonymous Coward

          removed the top plastic layer, exposing the recording medium beneath; cast a mold of the quasi-random pattern; and then used the mold to create a photovoltaic cell with the same pattern

          So you use your expensive photo lithography equipment to create a master, make as many molds from that as you like, and then create the photovoltaic cells from those. The mass production of BD-ROM discs is irrelevant, it just makes your master cheap, but when you're making 10,000s of cells the cost of the master is unimporta

          • removed the top plastic layer, exposing the recording medium beneath; cast a mold of the quasi-random pattern; and then used the mold to create a photovoltaic cell with the same pattern

            So you use your expensive photo lithography equipment to create a master, make as many molds from that as you like, and then create the photovoltaic cells from those. The mass production of BD-ROM discs is irrelevant, it just makes your master cheap, but when you're making 10,000s of cells the cost of the master is unimportant.

            Sure, but the cost is very relevant when you're doing research. This Blu-Ray disc experiment demonstrates that the theoretical work done previously will probably work as well as the theory predicts.

      • Re:BLUE ray (Score:5, Funny)

        by lgw ( 121541 ) on Wednesday November 26, 2014 @05:43PM (#48470495) Journal

        Replacing your roof with solar panels will always be an overhead cost!

        • Costs are often through the roof with these technologies; mounting complexities and steep installation costs result in flash peak expenses that only gutter out after years of trussing up the math in spreadsheets. Tiling the cells can shake out some additional margin, but just the thought of it gives me shingles.

    • by kf6auf ( 719514 )
      I expect that the reason the efficiency is increased is precisely because the pits are narrower than the wavelength of the light, making it less likely to be reflected and more likely to be absorbed. (You can view this classically as the index of refraction changing gradually.) If you use a pit size greater than the wavelength of the light, you'll end up with each photon either hitting the bottom of the pit or next to the pit, and the pit will have no effect.
    • In the paper they show the enhancement of quantum efficiency by wavelength. It's pretty uniform (+10-20%) throughout the 350nm (blue) to 700nm (red) range - and is really enhanced at longer wavelengths (>100%, but there isn't as much energy to be harvested here, so not as exciting as it sounds)

    • by pavon ( 30274 )

      If you look at the absorption and efficiency plots in the linked nature abstract, the improvement is pretty broad spectrum as it is. Based on the Fourier analysis plots, it does seem like a slightly wider pit spacing would better concentrate the energy in their desired sweet spot, but CDs and DVDs would be too wide. HD-DVD actually looks like it might have the most ideal pit spacings.

    • The pits on a blu ray disc are optimized for reading with a blue laser. Sun's output have more energy at the other end (red spectrum). I'm thinking they might get even better efficiency if they tried a disc pitting pattern that was meant for reading with a red laser.

      Actually, it works by simply reflecting the Sun in high-def. They tried this previously with DVDs (regular and superbit), Laserdisc, Betamax and VHS, with less efficiencies.

    • by synaptic ( 4599 )

      I think of colors of visible light in terms of bandgap energy -- red light has an energy of about 1.7 eV and blue light has an energy of about

  • by Ydna ( 32354 ) *

    Quasi random my eye. That's copyright infringement! Unleash the hounds!

  • How are there no references to the Jackie Chan cartoon show here? C'mon people...

  • by MarkRose ( 820682 ) on Wednesday November 26, 2014 @05:02PM (#48470231) Homepage

    I heard the first attempt was with Chuck Norris discs, but they burnt holes through the panels.

  • Maybe this means there will finally be a use for that Green Lantern movie dvd.
  • That's one helluva case of 'sticky hands'. Photons beware!

  • There is no way a Jet Li disc could accomplish this.

    • by fyngyrz ( 762201 )

      What's kind of funny is that the meme invokes Chuck Norris, a complete hack of a martial artist who came to fame in a time when crude technique was the general order of the day (Bruce Lee notably excepted.) Then you invoke Jackie Chan here, who is really pretty good; but you also disrespect Jet Li, who is nothing short of an awesome martial artist. 1-2-3 in skill inverted to 3-2-1 in offered kudos. All I can conclude is that the public has a very weird perception of martial artists.

    • There is no way a Jet Li disc could accomplish this.

      A Jet Li disc would not only accomplish this, but it would do it after it said it wouldn't.

  • What the HELL does the name of the movie on the disc, much less the star of said movie, actually contribute to this process / article? Confused clicks, thats what. I nominate this headline for this years "Most Worthless Headline" award.
  • by Dereck1701 ( 1922824 ) on Wednesday November 26, 2014 @05:58PM (#48470597)

    I wonder if they did any real world testing, as in a static solar panel and a complete day average. Somehow I would imagine these would make the solar panels great, during a narrow window of the day where the sun is directly overhead. I can't shake the feeling however that this kind of patterning would have a detrimental effect on indirect exposure. Not that it is a major issue, sun tracking systems are becoming more prevalent, but it may be an issue.

    • Seems to me like making the surface one big corner reflector would guarantee the maximum absorption. A DVD or CD has space between the tracks, but a corner reflector is guaranteed to reflect twice at a broad variety of angles...

  • Please correct me if i'm wrong, but isn't this an increase in the surface area of the solar cell..? Sure, some kind of pitting is going to be more effective at capturing rays (as one reader pointed out, sizing it for the red light of the sun) than a totally flat surface, assuming surface space is a factor in solar collection.. I imagine those minuscule pits would actually greatly increase the surface area of a disc.
  • you save all of your AOL cd's...
  • > solar panel that has a quantum efficiency of around 40%

    Conventional panels have a QE around 90%. That's why they're opaque.

  • If only they had used a Dragon Ball Z Blu-ray disc instead, the efficiency would have increased by over 9000%!!!.

Isn't it interesting that the same people who laugh at science fiction listen to weather forecasts and economists? -- Kelvin Throop III

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