# Space towers as a heat engine?

During an earlier discussion of the space elevator or tower, someone mentioned that you could use the temperature difference between the top
and bottom of a space elevator/tower to run a heat engine. However, I thought to have a heat engine you had to have the different heat reservoirs next to each other. Would it work if they were tens to hundreds of kilometers apart?
Bob Clark
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Not sure but see... http://www.enviromission.com.au /
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It works no matter how far apart they are provided you can transfer the heat to the engine without too much thermal resistance or loss (e.g. insulated heat pipes).

That's a bit different, try these:
http://www.bekkoame.ne.jp/~khirata/english/howwork.htm
http://www.stirlingengine.com /
George
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Robert Clark wrote:

[snip]
Yeah - witha 23,000-mile long extenson cord. Idiot. Yeah - with threading a conductor through the ionosehre out of orbit. Idiot.
Shove a therocouple up your butt, Clark. How much amperage can you draw?
--
Uncle Al
http://www.mazepath.com/uncleal /
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Uncle Al wrote:

someone
top
I WAS a question.
Bob Clark
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The idea is not without some merit. Only you don't need to get so grandiose... Pop the top off the elevator shaft of a NY or SF skyscraper, and you get a wind rushing through the center of the building that will eventually threaten the structural integrity of the complex. Put a screw or worm drive inside that shaft and it will easily turn a generator. Hell,on a windy day, with the flue to my chimney open, a constant 16 mph draft gets generated and that's only 2 levels. So, design a 50 - 100 ft tall vertical pipe with both ends open to the atmosphere, and a worm drive assembly inside it, and situate it in a windy area - free electricity that you can overcharge suckers and meatheads for!
Greysky
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Greysky wrote:

get a

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Good point. A wind turbine in the wind itself would create electricity. But you could also get *additional* electricity from the updraft created by the wind. This updraft gets created because by the Bernoulli principle increased velocity causes a decrease in pressure. So there is a pressure differential at the top and bottom of the tower. How much velocity do you think is created in the updraft dependent on the wind velocity? Here's a page that gives the formula for the power that can be generated by a windmill for a given wind speed:
How Can I Calculate the Amount of Power Available at a Given Wind Speed? http://www.awea.org/faq/windpower.html
Bob Clark Windmills
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both
Couldn't this 'updraft' somehow be utilized to increase the stability of the entire structure?
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the
Interesting idea. I guess it would be possible to fit a steerable nozzle or similar at the top to provide active damping in earth quake zones and the like. However ideally there wouldn't be much energy left in the air by the time it gets to the top - you want your turbine to have extracted it all.
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