On Jun 2, 2007, at 8:34 AM, Jones Beene wrote:
Horace
Unfortunately the energy you can get from gas buoyancy is way less
than the heat energy to get that buoyancy. Solar towers, for
example, run at less than 2% efficiency.
Yes but that is due to low Delta-T no? ...
No, it is not a Carnot problem, not directly. It has to do with the
(delta m_b) g d work available from the expanded gas, where (delta
m_b) is the incremental buoyancy due to the thermal energy applied.
If you could raise the mass all the way to space you might get the
energy back, but you'd be lucky to raise it a mile. The trick is to
get the remaining thermal energy back, so some kind of Sterling
engine or other heat energy recovery in the process makes sense.
Regards,
Horace Heffner
