Capacitor to store lightning?

Discussion in 'General Science & Technology' started by cato, Sep 21, 2004.

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  1. MacGyver1968 Fixin' Shit that Ain't Broke Valued Senior Member

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    If nothing else Benny...you got people to think...thanks!
     
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  3. MacGyver1968 Fixin' Shit that Ain't Broke Valued Senior Member

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    Point taken...I said I couldn't find a cap with greater than 20KV capacity...and you proved me wrong..by showing a cap that was 5 times greater in voltage capacity. I admit I was wrong. The simple fact is...my 20KV caps are made for both HV and HC. It really doesn't matter....all of this cost way more than other more reliable sources of renewable energy.
     
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  5. BennyF Registered Senior Member

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    This is what I said a moment ago.

    "I'm not trying to run a scientific experiment, I'm trying to sell hydrogen to paying customers at a profit."

    I almost forgot. I'm also trying to prevent deaths and injuries from direct lightning strikes, plus lightning-sparked wildfires, damage to buildings, animal deaths and injuries from being caught in a lightning-sparked wildfire, and let's not forget the residue from fire-retardant chemicals that are used to fight wildfires.
     
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  7. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    I suspected you would prefer to remain extremely ignorant.

    Wiki does have some errors,* but as thousands of well educated people do read and correct, that source tends to be better that a text book by a single author. With your attitude, you can not read anything some single person has written. - Thus, you must be very ignorant in many fields as you only trust your self-formed ideas.

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    *Generally you must be an expert in the field to even notice them, and often the "error" is just what wiki states a different POV than the one you hold to be fact. When it comes to physics there are no errors at your very low level of understanding. Thus, you could safely learn from Wiki articles.
     
    Last edited by a moderator: Mar 30, 2010
  8. MacGyver1968 Fixin' Shit that Ain't Broke Valued Senior Member

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    So...your going to build lightning collection facilities in the middle of forests...to prevent forest fires...that's mighty damn noble.

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    For your facilities to prevent lightning deaths and fires, they would need to be distributed to every square mile of planet earth.

    The more you speak...the more the Woo shows itself.
     
  9. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    I never said > 20Kv did not exist. I said:
     
  10. Captain Kremmen All aboard, me Hearties! Valued Senior Member

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    You misunderstood me.
    What I was saying was that the intense laser pulse is as little use as lightning, because it lasts such a short time. Same as lightning. I'll put the main point in big writing.

    If you haven't understood this time, I'm going to have to give up trying.
    Best of luck with your project.
     
  11. BennyF Registered Senior Member

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    Let me step out of my usual style and ask an honest question or two, instead of trying to offer advice and boast about my future accomplishments.

    Assuming, as I do, that northern Florida has the worst lightning problem in the country, and assuming, as I do, that there's a reason to prevent lightning from hitting people and buildings in northern Florida, here's my question. What would a simple grounded lightning rod have to look like (e.g. materials, height, architecture, etc) in order to be effective in, say, the Jacksonville area?

    What are the regulations that govern the height of such a structure? Which local, state, and national agencies would need to offer their approval before such a structure could be built?
     
  12. MacGyver1968 Fixin' Shit that Ain't Broke Valued Senior Member

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    Then there are a lot better ways of doing it. You mentioned N. Florida...if that is where you are based..then solar, (and possibly wind) by far is the way to go.

    I believe it is quite possible to capture at least some of the energy from a lightning bolt and use to to charge a bank of capacitors..that charge a bank of batteries that power inverters that power my business and electrolysis of water. That said...there are FAR FAR better ways to accomplish the same tasks.
     
  13. BennyF Registered Senior Member

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    This is strictly FYI.

    The University of Florida performs scientific research in a facility near Gainesville. Once again, my years of research turned up this tidbit a long time ago.

    The place is called Camp Blanding, because the research is done in cooperation with the U.S. Air Force. They clear the airspace long enough for the scientists to send up a rocket with a wire attached. Lightning hits the rocket, electricity travels down the wire (which promptly burns up), and the scientists study what they can.

    Here's the website run by the University of Florida:
    http://www.lightning.ece.ufl.edu/

    And here's the website run by the security company, which considers it a military installation:
    http://www.globalsecurity.org/military/facility/camp-blanding.htm

    The university web page has a long list of publications that have published scientific articles from 1993 to 2008 based on onsite research. Click on the "publications" link.

    If you click on the "Fulgarites" link, you'll see photos of objects that are created when lightning strikes sand.
     
  14. DRZion Theoretical Experimentalist Valued Senior Member

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    How on earth would you use a laser to draw lightning ??

    There are those who say his son has done the deed.

    Why only milliamperes? I do not mean directly drain charge as Franklin's kite did, but rather use an elevated object to draw lightning...

    I do not think the kite was on a metal wire string it was only 1750 and they did not have this kind of technology.
     
  15. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    The laser if pulsed only after the cloud had time to build up a high voltage and if it is powerful enough to ionize a line of air* to the cloud, it will quite likely draw lightning.

    If the laser were able to keep a continuous conducting path to the cloud, never would there be any lighting from that cloud. - The charge building in the cloud would be drained away as fast as it forms. The same is true true of your wires and metal towers.
    That is how lighting rods PREVENT lighting. - I.e. drain away the charge as it is produced. (It is more complicated than that as they change the equi-potential surfaces and thus the local electric field strength also.)

    It is interesting to note that AFAIK (certainly true 25 years ago) no one really knows how the cloud becomes charged to a high voltage. To do this you must have some way to separate in the air electrons from the positive ions that are made when the electron is removed from neutral N2, O2 or H2O molecules. I.e. how is this possible? What force overcomes the electrostatic attraction between the electron and the ion it is leaving? You can read a lot of hand waving about rising air currents, water drops, etc. but never is this force identified.

    *BTW this is essentially impossible (I think IS impossible, if the cloud is more 1000 meters above the laser). Problem is that the laser beam passing up thru the first meter of ionized air will no long be a well formed parallel beam. - Ionized air has a very different index of refraction and it would be very spatially varying across the beam. Sort of like trying to shine a flashlight beam thru a thousand sheets of frosted glass. This was a big problem with ground based laser weapons shooting at the photo voltaic panels of satellites - could not deliver significant energy density to even warm them. The spreading of the air ionizing laser's beam is called "blooming."

    This is why small rockets trailing a fine wire are used to draw lighting from clouds and not lasers, which could be cheaper than many rockets if many lightning bolts are to be produced.
     
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  16. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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  17. BennyF Registered Senior Member

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    Hi, Billy.

    First, please have a look at a post I just left on another board, referring to funny female perfume.

    Second, here's an interesting link I found about a year ago. These vehicles burn hydrogen. Yes, I said they BURN HYDROGEN.

    http://avt.inel.gov/hydrogen.html

    The link comes from the Idaho National Laboratory, which is testing them. There are no fuel cells in these vehicles. They use hydrogen directly as a fuel, instead of combining it with oxygen to produce electricity for an electric motor.

    I said before that H2 vehicles are ready NOW for large-scale production. All the manufacturers need is a country that has many H2 filling stations, so that people can refill their tanks whenever they need to.

    It is my hope, sometimes waxing, sometimes waning, that lightning can someday become an economical source of electricity, and that this electricity can someday be stored in large enough quantities to allow for the electrolysis of water, turning it into hydrogen and oxygen. The hydrogen would be shipped, perhaps in a metal hydride, to the H2 filling stations, and the oxygen would be sold to hospitals and nursing homes.
     
  18. BennyF Registered Senior Member

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    This topic was mentioned in a Tom Clancy novel called "The Cardinal in the Kremlin." In the story, Russia and the US were both competing to be the first to develop a laser weapon, for use in destroying satellites. In the story, Russia had one and tested it on one of their own satellites. A US Air Force plane saw it accidentally when they were cataloging the satellites, documented the technical details, sent the info to NORAD, and immediately landed their plane, feeling quite sad that the US had not been the first to develop such a weapon.
     
  19. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    As I discussed in prior post, from the ground that is impossible (unless you send beam backwards thru a very large diameter telescope mirror* so that in the air the energy density per unit cross section area of the beam is too low to even strongly heat the air). An adequate understanding of physics would have avoided the expense and the nonsense in Tom Clancy's story of trying from the ground.

    I.e. simple physics can often show some things, such as your extremely high voltage energy storage ideas, are essentially impossible. You would need several hundred long train loads of railroad tank cars filled with high dielectric strength oil to fill a tank with a base about the size of Manhattan Island and walls some miles high to prevent breakdown discharge of your stored energy (Even assuming it were possible to collect it from lightning).

    Too bad, in your ignorance you have wasted 4 years dreaming.

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    *With slight convergent secondary lens that concentrates beam back down / focuses it on the satellite.
     
  20. BennyF Registered Senior Member

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    Billy, it's been awhile since I read the Tom Clancy story, but I think that there were half a dozen separate lasers that were somehow "combined" to form the one beam that was computer-aimed at the malfunctioning Russian satellite.

    In the story, the Russians did experience the blooming that you mentioned, which reduced the heat that the satellite felt, but the laser put out enough wattage to fry the delicate satellite anyway. The Russian General who gave the final OK on the laser countdown called it "half a success" when he reported to his superior. The Russian satellite's trajectory was known to the Russians staffing the aiming computers, so all they had to do was to program in the coordinates where the satellite would be and the laser did the rest.

    As for my stored-lightning idea, I said I wouldn't be using a cap as big as a football stadium. That's because I intend to use more than one of them, all HV caps with voltage ratings of 100 kv or better. That would reduce the amperage down to a much more manageable level.

    Tell me, would it modify my need for dielectric oil if the capacitor is shaped like a cigar, with its' two electrodes at either end of the cap? In other words, if the distance between the two electrodes on a single cap is measured in feet instead of inches, how does that change the breakdown voltage?

    Benny
     
  21. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    To BennyF:
    “The dielectric strength of air is approximately 3kV/mm. Its exact value varies with the shape and size of the electrodes and increases with the pressure of the air.”
    Quote from: http://hypertextbook.com/facts/2000/AliceHong.shtml

    That is for very clean dry air. (Moist air in the electrode gap may arc over at less than 1kV/mm voltages.) Also you need a safety factor of at least 2 so for design purposes, figure that any point at 1 million volts must be two meters from the ground if in ordinary air. Likewise any point at one billion volts must be at least two kilometers above the ground to avoid electrical breakdown in air. Thus your “hottest” terminal at your planned 100 billion volts must be about 200 kilometers above the Earth’s surface. Actually even that would fail for reason I have already stated. Namely the condensers in the voltage string near the altitude of the atmospheric Paschen minimum would all short out with atmospheric arcs / breakdown. The UV from their arcs would short out most of the others plus now the total voltage is divided among the the non-shorted capacitors and that over voltaging them cause internal breakdown destruction of them, even without the UV.

    Here is a table of the typical dielectric strength of various materials:
    Substance Dielectric Strength (MV/m)
    Helium[1] 0.15
    Air[2] 0.4 - 3.0 (depends on pressure) [3]
    Alumina[1] 13.4
    Window glass[1] 9.8 - 13.8
    Silicone oil, Mineral oil[1] [4] 10 – 15
    Benzene[1] 16
    Polystyrene[1] 19.7
    Polyethylene [5] 18.9 - 21.7
    Neoprene rubber[1] 15.7 - 27.6
    Ultra pure Water[6] 30
    High Vacuum (field emission limited) [7]20 - 40 (depends on electrode shape) {and this assumes no UV on the cathode. Harsh UV there can greatly lower the gap breakdown voltage.}
    Fused silica [8] 25 – 40
    Waxed paper [9] 40 – 60
    Teflon[10] 60 Mica [11] 20 – 70

    From: http://en.wikipedia.org/wiki/Dielectric_strength (Square bracket numbers are reference Wiki has cited. Tom Clancy is not one.

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    They are serious studies.)

    Thus, if the entire voltage string were submersed in oil with a dielectric strength of 15MV/ meter, your 100 BV storage system might not need to be more than 13 kilometers tall. (All of the highest voltage points at least 13 kilometers above the ground surface.) However, there must be nearly 13 kilometers of oil covering their tops too. For example, it only a 100 meters of oil covers the top of the highest voltage electrode an arc will form up thru that 100 meters of oil and then down the 13,100 meters of air on the outside of the capacitor stack's oil tank. So really your 100 billion Volt storage system, if on Earth, must be in an oil tank about 24 kilometers tall. (It could be somewhat smaller in space, if well shielded from solar UV.) The Manhattan Island sized base is required to store the energy you need / want (to disconnect your office from the power lines.)

    Perhaps you are beginning to get a little understanding of how silly your ideas are?

    PS
    Your question about a cigar shaped capacitor does not make much sense* as normally there is one small high voltage electrode and the entire metal case is the other electrode. You seem to be thinking there would be two small electrodes at the ends of the cigar. What is the case (skin of the cigar)? At what voltage is this case if one end of cigar is at 0V and the other at 20Kv? For example is the case is at 10Kv? If so, then the 0V end electrode will arc over to it as the zero volt end is a cathode wrt the case. You also may create some internal arcs between the case and internal electrodes. Likewise the case will arc over to the 20Kv electrode as wrt to it, the case is the cathode. You would need some insulating circle rings near each end to make the case / end electrode gap more than the breakdown gap spacing.

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    *This just reflects how little you understand about high voltages.
     
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  22. MacGyver1968 Fixin' Shit that Ain't Broke Valued Senior Member

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    I tried to think of an analogy..and this was the best I could come up with.

    Essentially, you are digging a 200ft deep water well with a spoon, in order to extract a gallon or two of water that sporadically forms a month and sometime not at all. Water that needs to go through an expensive filtering process to be even usable...when you live right next to a clear mountain stream that flows year round, and requires little to no filtering before use.

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  23. DRZion Theoretical Experimentalist Valued Senior Member

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    Yes, I heard about this problem with high powered lasers. This is the same reason why military lasers are limited in their usefulness. It would be nice if by ionization the refractive index of air would be lowered. This way the laser might burn a path in air which would guide trailing parts of the beam much like a fiber optic cable. I assume this is not the case.


    I like the idea of the rocket with the string - but if this works, why wouldn't a helium balloon with wire work?
     
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