NetNews Usenet Archive 1992 #31/NN_1992_31.iso/spool/sci/electron/21498

Internet Message Format | 1992-12-23 | 3.3 KB

Xref: sparky sci.electronics:21498 sci.energy:6422 rec.autos.tech:17125
Path: sparky!uunet!munnari.oz.au!metro!otc!elson
From: [e-mail] (Elson Markwick)
Newsgroups: sci.electronics,sci.energy,rec.autos.tech
Subject: Re: Flywheel batteries as EV power source
Message-ID: <[e-mail]>
Date: 23 Dec 92 22:18:45 GMT
References: <[e-mail]> <[e-mail]>,<[e-mail]> <[e-mail]>
Sender: [e-mail]
Organization: R&D, OTC Sydney, Australia
Lines: 46

In article <[e-mail]>, [e-mail] (Carl J Lydick) writes:
> In article <[e-mail]>, [e-mail] (gregg hanna) writes:
> =At least some energy would be absorbed heating up the Halon as it
> =expands from the tank, and then the mixture would hit air.
>
> A trivial fraction of the energy involved.  A big problem in this discussion is
> that many people simply don't seem to have the vaguest idea as to just how much
> energy is involved.
>
> Carl J Lydick | INTERnet: [e-mail] | NSI/HEPnet: SOL1::CARL

I missed the first part of this debate, and I didn't get to see any figures being
thrown around, so roughly how much energy *would* be invloved?  For a rough
calculation, say you want your vehicle to be able to travel for 3 hours, and
consumes a road horsepower of 30hp (sounds fairly excessive to me, even for a
petrol engined car - an electric will use a lot less road horsepower than an IC
powered car), I get about 250 MegaJoules.  Obviously, the more you can reduce the
road horsepower, (less loss in the drivetrain, however the drivetrain is
organised, more aerodynamic, etc etc) the lower your stored energy would need to
be.  Also, if the vehicle were to be used as a commuter car, (say half hour trips
between work and home, where you had an outlet at work to recharge the system),
the required energy would be much less, due to both shorter duration trips, and
a lower required speed, which implies less road horsepower, then the required
energy would be even less.

Having said that a flywheel of usable size and weight for cars would still have to
spinning at some incredible speed, which in turn would mean there'd be one hell
of a strain on the flywheel (not to mention balancing problems).

Given that, I'd have to agree with the guy who said that flywheel batteries are
better suited to stationary environments, where they aren't constrained so much
by size (ie - a much bigger, slower spinning flywheel).  Alternatively, they
could be used in cars along with another source of energy, to help supply peak
energy requirements, such as starting from traffic lights.  If you could use the
flywheel as a store for regenerative braking, then you could use a much smaller
IC engine as the main power source.  Also, they'd be useful for city traffic,
where a good percentage of the time is spent stationary (at traffic lights).  The
IC engines in cars today still tick over when the car is stationary, just wasting
energy.  Why not tap that and use it for recharging the flywheel?

Cheers, Elson
--
Elson Markwick |ACSnet:  [e-mail]
OTC R & D Unit |UUCP: {uunet,mcvax}!otc.otca.oz.au!elson
Ph: 02 287 3142|Internet: [e-mail]
Fax:[phone]|Snail:  GPO Box 7000, Sydney 2001, Australia