Look, you seem like a nice guy who is genuinely enthused about this, which is probably why so many people are taking the time to reply to you and try to explain things rather than simply blowing you off. But it's very difficult to believe that you graduated from an electronics school without learning about inductance.
Capacitor to store lightning?
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30 KA * 100 KV = 3E9 W = 3 GW.
3 GW * 0.03 seconds (not 0.003) = 9E7 J = 90 MJ = about 25 kw hours, or about $2.50 worth at average US prices.
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It's an interesting subject for debate, or it would have died down long ago.
Would it be possible to send a balloon up into thunderclouds with something on board to collect the energy?
Would it be possible to send a balloon up into thunderclouds with something on board to collect the energy?
Thanks for correcting my math. I need to check my decimal places more carefully.
No; but with a conducting wire to ground it would be. The balloon would be small compared to the cloud, which is too conductive to have very much electric field strength (V/meter) So even a 100 meter balloon would have at most a few volts from one side to the other.
Also unless you had some plan for converting the energy to chemical storage, instead of capacitors, the weight to store any interesting (say a dollar's worth) amount of energy would be too much for the balloon to lift.
Fraggle Rocker
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That was very graciously put. You should get an award for it. As I recall, we covered inductance in EE101a.
I did learn about inductance in my school. I just haven't put any coils into my schematics, so I don't see any inductance unless you're referring to the coiled metal parts that are inside most capacitors.
Billy wrote about the inductance that's in every wire, but unless I'm mistaken, those values are as small as the voltage loss due to the resistance in each wire.
Billy, the following chart appears in some of the physics textbooks I own. Yes, I own some physics textbooks, but the concepts I have discussed so far seem like simple HV electricity, not anything "quarky", if I can borrow (and mangle) an astronomy term.
http://i970.photobucket.com/albums/ae190/BennyF_2010/th_RCCurves.gif
As explained by this chart, the voltage levels during (a) a capacitor charging event, or (b) a capacitor discharging event are governed by the amount of resistance, not the amount of inductance. You've been talking about the "system inductance", Billy, but I don't see it, I'm still not showing you my schematics, and I want you to explain where the inductance comes from.
Benny
The link in the previous post was a tiny copy of the graph. Here's a link to the whole page from one of Western Washington University's physics professors:
http://www.ac.wwu.edu/~vawter/PhysicsNet/Topics/DC-Current/RCSeries.html
The RC charging/discharging curves are about 2/3 of the way down on the page.
Benny
http://www.ac.wwu.edu/~vawter/PhysicsNet/Topics/DC-Current/RCSeries.html
The RC charging/discharging curves are about 2/3 of the way down on the page.
Benny
Captain, I found this tidbit a few years ago, during the early part of my four-year ongoing research project. The idea was posted by someone with a screen name "Vernon", and it's dated 09/24/01. The text of the idea is quite long, so I'll simply include a link to the web page:
http://www.halfbakery.com/idea/Lightning_20Power_20Plant
Please note that the page also has other "half-baked" ideas on how to collect the voltage (their terminology) from lightning.
Benny
Benny,
From what I can tell, you and I have about the same educational background. I have a 2 year associate's degree in electronic engineering technology....a technicians degree. Although mine is about 15 years newer than yours.
I think you are missing the point. While it might be possible to capture at least some of the energy from a lightning bolt, the costs involved far FAR outweigh the amount of energy that could be collected. There are far better, and cheaper ways of extracting renewable energy. I believe you are seriously underestimating the size and cost of a capacitor bank capable of capturing the energy levels in lightning bolt.
From what I can tell, you and I have about the same educational background. I have a 2 year associate's degree in electronic engineering technology....a technicians degree. Although mine is about 15 years newer than yours.
I think you are missing the point. While it might be possible to capture at least some of the energy from a lightning bolt, the costs involved far FAR outweigh the amount of energy that could be collected. There are far better, and cheaper ways of extracting renewable energy. I believe you are seriously underestimating the size and cost of a capacitor bank capable of capturing the energy levels in lightning bolt.
MacGyver, I'm afraid your guess about my educational background flatters me way too much. I attended all-day clases for seven months. All students learned about electricity before splitting into two groups. One group (mine) learned about digital electronics, the kind used in 1970s computers, and the other group learned about radio and tv electronics, so that they would be qualified to repair them when they broke.
There's also one other difference between me and most of the posters who I have seen here. I seem to be the only one who is concerned with preventing lightning damage and death to people and animals.
As for the economics of a capacitor bank, I haven't seen any prices on the HV caps I want to use, and I can't begin to guess what the labor costs will be (at least two years from now) for the technicians who will build the system under the direction of an engineer or two, and I'm sure that the local, state, and federal officials will want to collect their fees on such a heroic feat of engineering, plus there will be the cost of the building(s) which will encompass the capacitor bank, plus office space.
All I know is that nobody (I said NOBODY) has ever been able to generate a single volt of electricity, using lightning as his power source, and that lightning still kills 80-100 people every year, plus the economic damage it does to man-made structures.
There's also one other difference between me and most of the posters who I have seen here. I seem to be the only one who is concerned with preventing lightning damage and death to people and animals.
As for the economics of a capacitor bank, I haven't seen any prices on the HV caps I want to use, and I can't begin to guess what the labor costs will be (at least two years from now) for the technicians who will build the system under the direction of an engineer or two, and I'm sure that the local, state, and federal officials will want to collect their fees on such a heroic feat of engineering, plus there will be the cost of the building(s) which will encompass the capacitor bank, plus office space.
All I know is that nobody (I said NOBODY) has ever been able to generate a single volt of electricity, using lightning as his power source, and that lightning still kills 80-100 people every year, plus the economic damage it does to man-made structures.
I have a better idea.
Since you point out that lightning kills...
Instead of trying to harness that energy in capacitors, (which is not feasible at this time) set Death Row felons on poles in high thunderstorm areas.
All problems solved AND think of the savings on electric bills for the chairs.
Since you point out that lightning kills...
Instead of trying to harness that energy in capacitors, (which is not feasible at this time) set Death Row felons on poles in high thunderstorm areas.
All problems solved AND think of the savings on electric bills for the chairs.
Yes BennyF the voltage Vc (t) builds up in an initially discharged capacitor charging from a constant voltage Vb source as: Vc(t) = Vb (1-e^-t/rc)
IF the time constant RC is large compared to the time constant LC. I.e. then the inductance L can be ignored.
Typically, especially when charging from a battery, the time constant RC is several seconds. In your planned application two things are different:
(1) You do not have a constant voltage source.
(2) You must have RC very small compared to one second.
I.e. You want to use many (say N) individual capacitors with high voltage (>20kV) rating and at least C= 10 or more micro Farads in series. Thus the effective capacitance of the string, Ce will be C/N. For example, when N is one million Ce is a million times smaller than C (Ce is very small).
Likewise you will have R very small to avoid having all the power dissipated in the wires interconnecting these physically large individual capacitors. Thus your RC time constant should be less than 0.001 seconds* as the lightning bolt is over in about 0.03seconds.
SUMMARY:
With these conditions (many wires, or straps if you follow my advice, interconnecting you individual capacitors, which are physically large) the LC time constant cannot be ignored. In fact unless you pay a extra for low inductance capacitors, it very like controls the rate at which the current can build up in your capacitor string. I.e the simple large RC time constant curves you have copied and posted do not apply.
PS I am still waiting for you to reply to my post that explains why you are fundamentally wrong in most of your ideas. Read it at:
http://www.sciforums.com/showpost.php?p=2512112&postcount=153
* In fact your Ce being so small and your use of straps for low resistive loss as the interconnections between your many individual capacitors will probably make your RC time constant only a few micro seconds. Thus the LC time constant will probably about 100 times larger and dominate. - I.e. it will limit how fast you can put charge into your capacitors.
As I have already told you, most of the voltage will be across the inductance and the lightning will just continue its air arc to ground, by-passing your circuit. One does not want or need to see your circuit and given how ignorant you are about all this, it would only be good for laughs.
IF the time constant RC is large compared to the time constant LC. I.e. then the inductance L can be ignored.
Typically, especially when charging from a battery, the time constant RC is several seconds. In your planned application two things are different:
(1) You do not have a constant voltage source.
(2) You must have RC very small compared to one second.
I.e. You want to use many (say N) individual capacitors with high voltage (>20kV) rating and at least C= 10 or more micro Farads in series. Thus the effective capacitance of the string, Ce will be C/N. For example, when N is one million Ce is a million times smaller than C (Ce is very small).
Likewise you will have R very small to avoid having all the power dissipated in the wires interconnecting these physically large individual capacitors. Thus your RC time constant should be less than 0.001 seconds* as the lightning bolt is over in about 0.03seconds.
SUMMARY:
With these conditions (many wires, or straps if you follow my advice, interconnecting you individual capacitors, which are physically large) the LC time constant cannot be ignored. In fact unless you pay a extra for low inductance capacitors, it very like controls the rate at which the current can build up in your capacitor string. I.e the simple large RC time constant curves you have copied and posted do not apply.
PS I am still waiting for you to reply to my post that explains why you are fundamentally wrong in most of your ideas. Read it at:
http://www.sciforums.com/showpost.php?p=2512112&postcount=153
* In fact your Ce being so small and your use of straps for low resistive loss as the interconnections between your many individual capacitors will probably make your RC time constant only a few micro seconds. Thus the LC time constant will probably about 100 times larger and dominate. - I.e. it will limit how fast you can put charge into your capacitors.
As I have already told you, most of the voltage will be across the inductance and the lightning will just continue its air arc to ground, by-passing your circuit. One does not want or need to see your circuit and given how ignorant you are about all this, it would only be good for laughs.
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Neverfly, please put these inhumane thoughts on another board. Even without the benefit of a college degree, I have been trying hard to solve a problem that has existed for two and a half CENTURIES: How to take the idea of a Leyden Jar (the original capacitor) and apply it to the tremendous amount of energy in a lightning bolt.
Lightning kills, and I want to stop it while generating useful voltage from it.
Lightning kills, and I want to stop it while generating useful voltage from it.
While you're at it, can you solve FTL, too?
Inhumane- maybe, actually. I'm not a big supporter of the death penalty. Too many innocent people get thrown on death row.
Billy, I composed and tried to post a reply to your post, but it didn't make it past the Editor's Desk. Perhaps it was too long, perhaps someone saw the text as I was typing it and decided it should not be seen for whatever reason ...
In any event, I'm getting even more nervous, because I think that you're not just here to discuss physics, or its' subset - electricity. I think you want a look at my schematics, so that you can beat me to the patent office, so I will limit what I write about my system, to keep you (and everybody else) deliberately in the dark. You can see my schematics after I get my patent, which won't specify voltage ratings on the caps, current ratings on the wires, or the size of my office staff.
Benny
I'm sorry, but that is an Appeal to emotion. Lightning strikes don't kill that many people, it is a very rare event. The costs involved FAR FAR exceed any benifits.
To all who want to have a serious discussion of an electrical method of charging one or more capacitors, using lightning as a DC source:
The RC time constant that appears in many physics textbooks assumes that a resistor will be inserted in series with the capacitor. If you take out the resistor, and charge a capacitor directly from a DC source, the only resistance in the circuit is the resistance of the wires themselves, which could be designed to be a multi-stranded copper wire with, say, a 3/4" outside diameter, leading into, say, a capacitor bank consisting of, say, a hundred current branches with, say, a hundred HV caps in each branch.
In this hypothetical system, each and every capacitor, initially uncharged and undamaged, has a real "thirst" for electrical energy, and would be able to drink a lot of it in a very short time, which is nice, because the electricity from the lightning bolt would only last for a very short time.
Oh, I forgot. The thunderstorm just might hit your collector a hundred times before the storm moves away.
The RC time constant that appears in many physics textbooks assumes that a resistor will be inserted in series with the capacitor. If you take out the resistor, and charge a capacitor directly from a DC source, the only resistance in the circuit is the resistance of the wires themselves, which could be designed to be a multi-stranded copper wire with, say, a 3/4" outside diameter, leading into, say, a capacitor bank consisting of, say, a hundred current branches with, say, a hundred HV caps in each branch.
In this hypothetical system, each and every capacitor, initially uncharged and undamaged, has a real "thirst" for electrical energy, and would be able to drink a lot of it in a very short time, which is nice, because the electricity from the lightning bolt would only last for a very short time.
Oh, I forgot. The thunderstorm just might hit your collector a hundred times before the storm moves away.
The Iowa thunderstorm I documented earlier peaked at over 450 strikes PER MINUTE. That was just one storm. I have no idea whether this storm damaged any buildings or killed any people, but I do know (because I've seen the stats) that 80-100 people EVERY DAMN YEAR die from lightning IN THIS COUNTRY ALONE.
Almost all of the localized lightning detectors I have access to, because I know their web addresses, are in this country, but there is one exception. I have the web address for a lightning scan somewhere in Sasketchewan, Canada, and yes, I've seen lightning strikes appear on this website.
I also mentioned earlier that lightning hits the CN Tower in Toronto over twenty times every year. The actual figure I saw was 26 times every year. Wouldn't it be nice if a large cap bank were to be installed in their building, so that all this electricity could be collected, stored, and converted into AC for their own benefit?
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