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

"Robert Clark" wrote in message
ups.com...
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?

Not sure but see...
http://www.enviromission.com.au/

"CWatters" wrote in message
...

"Robert Clark" wrote in message
ups.com...
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?

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).

Not sure but see...
http://www.enviromission.com.au/

That's a bit different, try these:

http://www.bekkoame.ne.jp/~khirata/english/howwork.htm

http://www.stirlingengine.com/

George

Robert Clark wrote:

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.
[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/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/qz.pdf

Uncle Al wrote:
Robert Clark wrote:

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.
[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?

...

I WAS a question.


Bob Clark

"Uncle Al" wrote in message
...
Robert Clark wrote:

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.
[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

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

Greysky wrote:
...
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

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

"Greysky" wrote in message
om...

"Uncle Al" wrote in message
...
Robert Clark wrote:

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.
[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

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



Couldn't this 'updraft' somehow be utilized to increase the stability of the
entire structure?

"Matthew Hagston" wrote in message
ink.net...

Couldn't this 'updraft' somehow be utilized to increase the stability of
the
entire structure?

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.