How many kJ in a 100 volt, 1 farad capacitor? On Wed, Aug 26, 2009 at 11:25 PM, Craig McCluskey <diese...@pisquared.net>wrote:
> On Wed, 26 Aug 2009 23:26:34 -0400 Allan Streib <str...@cs.indiana.edu> > wrote: > > > Craig McCluskey <diese...@pisquared.net> writes: > > > > > Jim's comment about how much momentum a moving freight train has is > > > indicative of the size of flywheel you would need. It wouldn't fit on > > > the train and couldn't fit through tunnels and across bridges. > > > > I'm imagining some kind of giant, box-car sized capacitors that would > > absorb energy during braking and release it back to the motors during > > acceleration. Again, probably impractical or they'd be doing it. > > Well, there have been recent improvements in capacitors that allow them to > store more energy, but I don't remember the energy storage density. > > To get an idea of how much energy one would need to store, consider a > locomotive accelerating a train from stop to some speed. Say, for example, > we have a 4000 horsepower locomotive that runs for 10 minutes to get the > train moving. That's > 746 watt 60 seconds > 4000 horsepower x ---------- x 10 minutes x ------------ > horsepower minute > > = 1.79 x 10^9 watt-seconds = 1.79 x 10^9 Joules = 1.79 x 10^6 kiloJoules > > > If the energy storage density is 10 kJ / cubic foot (not too far off, I > think) the volume of the capacitor would be 100,000 cubic feet. If the > energy storage density is 100 kJ / cubic foot, the volume of the capacitor > would be only 10,000 cubic feet. > > > Craig > > _______________________________________ > http://www.okiebenz.com > For new and used parts go to www.okiebenz.com > To search list archives http://www.okiebenz.com/archive/ > > To Unsubscribe or change delivery options go to: > http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > -- OK Don Pair of W124 300D 2.5 Turbos -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://okiebenz.com/pipermail/mercedes_okiebenz.com/attachments/20090827/e38ec9d3/attachment.html> _______________________________________ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
