[SGVLUG] [OT]Hybrids and trains (was fuel prices and the dollar)

[David Lawyer]

On Fri, May 16, 2008 at 06:34:21AM -0700, Dan Kegel wrote:

> Perhaps the real answer is... SOLAR STEAM TRAINS!!!!
> http://solarsteamtrain.com
> - Dan
> 
Today we have oodles of proposals to increase energy-efficiency, most
of which will not work as claimed.  The solar steam proposals lack
detailed calculations so to debunk them would likely require about 10
times the effort as was put into making them.  Furthermore, it needs
to be done by someone who knows a lot about steam engine efficiencies
and solar power efficiencies and there may be no such person
available.  It turns out that many times more effort is being put out
by people making such proposals than by people trying to determine the
accuracy of these proposals, while it needs to be the other way
around.

Steam locomotives were phased out all over the world due to low
efficiency.  The ones in the US had only about 5% thermal efficiency.
One proposal at this site (there are various different proposals there) 
is to fuel the locomotive with a molten compound (like salt) and then
extract heat from that substance as it solidifies (like extracting
heat from water as it freezes).  Unfortunately, the temperatures are
not nearly as high as the combustion temperatures one gets from
burning fossil fuels and thus lower thermal efficiencies.  The energy
density of molten fuel is quite low (as compared to fossil fuels) so
the range of operation of such a locomotive would be quite short.

One proposal is to get the heat to melt the salt (or other compound
such as superheated water) by burning biofuels.  Doesn't sound very
efficient to me.  Why not burn the biofuels directly on the
locomotive?  And biofuels may require more energy to make than they
release.  If solar energy is used, trains only run when the sun is
shining brightly.

			David Lawyer