Re: Electricity from garbage

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

Re: Electricity from garbage (DA Morgan)

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

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
(Do something naughty to physics)

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