barometric power?

[moth]

if you had a tube with a piston in the center,and you put valves at each end of the tube so when the barometer is high air is allowed in one end of the tube and out of the other end when the barometer is low, would the piston move?

[CaptainPanic]

Yes.

 

But I think it's more exciting to watch the paint dry.

 

In addition, I think the amount of energy that you can get from this system is disappointingly small, unless you build it at a planetary scale (but then I suggest you call it "windpower", and you should use wind turbines for it. After all, wind is caused by pressure differences).

[moth]

thank you for your reply CaptainPanic, i imagine watching paint dry would accomplish more than watching this contraption.

i was focusing on the huge pressure available more than the motion. for a 10' diameter piston and a moderate change in the barometer, i think a ton or two of force would be generated.

maybe i could translate the force to one more suitable for the power requirements of some task, like running a flywheel/generator or something .

[CaptainPanic]

Well, you know the force that is available (pressure is force / area). You know the displacement, and you can estimate the frequency of the change in atmospheric pressure... so you can estimate how much power you can get from this...

 

I suggest that you calculate it before building anything.

[moth]

thanks for looking at this CaptainPanic.

it seems similar to high voltage with no amperage. half a mm per week is like going nowhere.

i just wanted to know if i could come up with an answer.

[J.C.MacSwell]

Now, paint this thing black and add some sun to this thing.

[moth]

every bit would help. if there was a paint that could be switched from absorbing heat to reflecting it the piston could still be driven in either direction. i looked at an equation for pressure that involves heat, but the entropy term scared me.

and the 10 mBar a week estimate was from looking at a weather map(barometric records are not free) but i imagine the "random walk" of the pressure might add up to quite a bit more.i read in wikipedia the atmosphere has lunar tides so you also get a little bump twice a day.

still, as CaptainPanic pointed out i might as well just use a windmill(the neighbors won't mind, they're too far away)