[ExI] Accelerando

[scerir]

Damien
> > Still, I'm sure there are new ideas waiting to be explored, or old ideas
> > waiting to be examined in depth--but it's not obvious what they are. (I'm
> > waiting eagerly for Keith to tell us what his current idea for cheap 
energy
> > is.)

BillK
> Many of us have been to the gym and wondered why the exercise
> equipment isn’t hooked up to generate electricity and feed it back
> into the grid. 

Since there is a lot of noise [not just on this list :-)] I would
propose thermo-acoustic generators (generation of heat/energy
from noise). 

If heat is given to the air at a moment of greatest condensation, 
and is taken from it at the moment of greatest rarefaction, a vibration 
is encouraged. If heat is given at the moment of greatest rarefaction, 
or subtracted at the moment of greatest condensation, the vibration is 
discouraged.
By this process heat is converted into acoustic power and a self-sustained 
oscillation can be reached. For thermo-acoustic generators the process is 
reversed.

http://en.wikibooks.org/wiki/Engineering_Acoustics/Thermoacoustics
http://uw.physics.wisc.edu/~timbie/P325/Fahey_thermoacoustic_oscillations.pdf
http://en.wikipedia.org/wiki/Thermoacoustic_hot_air_engine
http://www.americanscientist.org/issues/feature/the-power-of-sound/2
http://www.mecheng.adelaide.edu.au/avc/thermoacoustics/