Re: Electricity from garbage

Posted by Uncle Al on Mar 10, 2004 at 15:22
(68.99.179.162)

Re: Electricity from garbage (DA Morgan)

Your link needs work, and "New Scientist" is the "Enquirer" of tabloid science.

http://www.newscientist.com/news/news.jsp?id=ns99994761

The "projected" output is like the jobs Bush the Lesser has created in the past 3.5 years. It is in your dreams.

How many kilowatt-hrs of electricity do you get for each pound of input? A pound of coal burned liberates enough energy to insert a pound of coal into low Earth orbit:

Tabulated heats of combustion for coals range from 2.4-3.2x10^7 J/kg. The all-purpose heat of combustion rule: 5 eV for every molecule of O2 used. This gives 4x10^7 J/kg for pure carbon oxidized to CO2, and is consistent. For an object in low Earth orbit v^2 = Rg, and the kinetic energy/kilogram is Rg/2. With R = 6x10^6 m (from the center of mass) and g =10 m/s^2 that works out to 3x10^7 J/kg. A rocket uses 100X as much enrgy to put a kilogram of payload in low Earth orbit.

(A better number for gee is 840 cm/sec^2 at 300 miles altitude)

A Peltier cooler strapped to your back runs in reverse and produces energy from the thermal gradient. No effluent, either. So what?

--
Uncle Al
http://www.mazepath.com/uncleal/qz.pdf
http://www.mazepath.com/uncleal/eotvos.htm
(Do something naughty to physics)