Half a croissant, on a plate, with a sign in front of it saying '50c'
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Make mine a double.

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stirling underwaterwheel generator

low-tech external combustion.
  (+7, -2)
(+7, -2)
  [vote for,

Imagine an underwater waterwheel in a sealed vessel that runs on the buoyancy of air. The vessel is filled with water. Blow pressurized air into a port at the bottom, and the bubbles turn the wheel, producing work.

The sealed vessel is connected to a large drum by a pipe. Between them is a one-way valve. Air can be forced in, but water cannot flow back into the drum. The Drum is heated, and the expanding air is forced into the vessel, turning the wheel.

Another pipe at the top of the vessel channels the air back to the drum, through a one-way valve, with the use of a pump. The pump is powered by the turning wheel. The air cools as it passes trough the water. The water is further cooled by a radiator system. It is then pumped into the drum.

The cold air expands after it is pumped in, is forced into the vessel, etc. The cycle is continuous, and no displacement plug is needed.


External combustion; runs on anything that will burn


few moving parts

Relatively easy to build with shop tools, plumbing, old water tanks, and off-the-shelf parts.


Probably enormously inefficient.

Would have to be geared up something awful.

May not work at all.

nomocrow, Nov 27 2006


       //Air going up does not exert a incredible force// It exerts enough of a force to keep large military vessels afloat - it's just a question of scale.   

       I guess the stirling connection is that applying an external heat-source is enough for it to start operating.
zen_tom, Nov 28 2006

       Air exerts the same amount of force going up as the water it displaces would exerts if it were going down.   

       It's a stirling cycle. Hot expanding air displaces a mass, doing work. It is cooled, and then displaced back into a cylinder, where it is heated again. This system just uses different means to move the air around and a different means to get the work out of expanding air.
nomocrow, Nov 28 2006

       I'm not trying to float a ship, only run a generator.   

       Again, air exerts the same amount of buoyant force as the amount of water that it displaces exerts when falling.   

       One pint of water gives you a pound of pressure. If you displace a pint of water, you have one pound of pressure going up. If you are suggesting that the device would be impractically big, well, no crap. I've got dumber ideas than this one.   

       For instance, you could put the drum on top, inject steam into it, collapse the steam, and make the thing work like a giant bong steam engine. You could call it "Watt-a-Bong."
nomocrow, Nov 28 2006

       Welcome [nomocrow].+
zeno, Nov 28 2006

       Thanks, dude.
nomocrow, Nov 28 2006

       Hello, [nomocrow]. I think this would work. I don't think this would run continuously - if it did you wouldn't need the one way valves. To move the air into the bottom of the vessel, you need pressure to displace the water there. This pressure would be have to be matched by the pump. The pump would be doing the work by forcing the air into the water. It doesn't matter that the air on top is cooler/more dense, it still needs to be pumped at the same pressure.   

       The way it would operate is in bursts, bursts of pressure through the one way valves. You don't even need the air pump. It would be very similar to a drip coffee maker with a water wheel that cools the coffee in the pot and allows it to flow back into the reservoir through a one way valve. Except that this has bubbles instead of drips. All the turbulence of the bubbles might make it inefficient, but I think this is a very cool idea. +
jmvw, Nov 28 2006

       Then again, this may not work at all. I was thinking that there would be pressure waves that would move the air out the top valve. Obviously I was half thinking when comparing this with a drip coffee maker. Coffee makers rely on the boiling of the water beyond the check valve.
jmvw, Nov 30 2006

       This isn't relevant at all, but I was looking at the HB thruogh the 'Gizoogle' translation and this came up as "stirl'n underwizzle generizzle", which just sounded too interesting to not read.   

       [Lt] I like the tagline. You should add it to UB's (mostly lame) list
hidden truths, Nov 30 2006

       This just needs a little tweaking. Perhaps the whole thing needs to rotate on a horizontal turntable connected by a gearbox to the bubble wheel. Install near an underwater volcano.
jmvw, Dec 01 2006


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