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- Xref: sparky sci.electronics:21008 sci.energy:6210 rec.autos.tech:16827
- Newsgroups: sci.electronics,sci.energy,rec.autos.tech
- Path: sparky!uunet!noc.near.net!news.cs.brandeis.edu!chaos.cs.brandeis.edu!andyh
- From: andyh@chaos.cs.brandeis.edu (Andrew J. Huang)
- Subject: Re: Flywheel batteries as EV power source
- Message-ID: <1992Dec17.192329.25210@news.cs.brandeis.edu>
- Sender: news@news.cs.brandeis.edu (USENET News System)
- Organization: Brandeis University
- References: <1992Dec15.194558.2556@adobe.com> <1992Dec16.192456.6261@news.cs.brandeis.edu> <1goebdINNik@gap.caltech.edu>
- Date: Thu, 17 Dec 1992 19:23:29 GMT
- Lines: 66
-
- In article <1goebdINNik@gap.caltech.edu> carl@SOL1.GPS.CALTECH.EDU writes:
- >In article <1992Dec16.192456.6261@news.cs.brandeis.edu>, andyh@chaos.cs.brandeis.edu (Andrew J. Huang) writes:
- >=In article <1992Dec15.194558.2556@adobe.com> pngai@adobe.com (Phil Ngai) writes:
- >=<I have to admit an emotional response to this since I think that
- >=flywheels have tremendous potential.>
- >The problem isn't with their potential, it's with their kinetic.
- Presumably this is a pretty good pun rather than a counterpoint
-
- >=Since the energy is kinetic, a lot of it will end up as particle
- >=velocity.
- >Partcles of what?
-
- whatever materials are around. e.g. carbon fiber, aluminum housing,
- kevlar scattershield, flesh.
-
- >=Some will dissipate into the air as air friction (some hot
- >=air as a side effect).
- >What air? The flywheels are supposed to operate in a vacuum.
-
- The air that surrounds the housing. Yes, within the housing air
- friction is designed to be a non-issue, but since we're discussing the
- destruction of the housing, there will be air around.
-
- >You seem to've missed something here. It's called the law of conservation of
- >energy. While energy will go into these paths you can't just say, as you're
- >trying to:
- > A lot of it will end up as particle velocity, so now we can
- > ignore that.
- <deletion>
- >Er, the amount of energy that escapes is exactly the amount of energy you
- >started with. Law of conservation of energy comes into play. All the energy
- >from the flywheel will have been converted into these other forms...
-
- Yes, it is obvious that energy is conserved and no I do not postulate
- a violation of conservation of energy. But when you take a car going
- 80mph and hit a bridge, where does all that energy go? Into bending
- the sheet metal, breaking glass, throwing tires etc. However, is the
- bent metal going to hurt you? My point is that the disintegration of
- parts consumes energy, taking kinetic energy and converting it to
- heat. I think that the kinetic energy is likely the more dangerous
- form, depending upon the environment. (Of course heat will kill you
- too, but it depends on the temperature).
-
- >It didn't just vanish. And that's a LOT of energy. And it got dumped FAST.
- >In other words: BOOM!
-
- Take a 50's Caddy going 100mph. Put it into many barrels of sand.
- Did it go BOOM?
-
- Take a loaded tractor-trailer with bad brakes. Put it down a mountain
- road. Send it up the "Failed Brakes" escape road. Did it go BOOM?
-
- I don't claim to _know_ that an explosion of these flywheels is safe.
- I have read a report in the press that the manufacturer's TESTING
- showed an apparently safe catastrophic failure. My post was to give
- some _possibilities_ about why the failure was safe. My post was also
- to counteract the hysterical reaction "I hope they do lots of crash
- testing before letting such a dangerous thing on the roads". I don't
- see the evidence that it is dangerous. There is some intuition, some
- hunches, etc, but this has not been born out by the manufacturer's
- _TESTING_. Whether you believe them or not is another issue.
-
- -andy
-
-
-
-