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Author Topic: Geo_engineering with short space elevators  (Read 179 times)

morganism

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Geo_engineering with short space elevators
« on: August 05, 2017, 11:50:06 PM »
Geo-engineering with short space elevators.

" Let us just assume we can build a chimney 5 kilometers (3 miles) high. Let us call it a super-chimney. The air at the base of this super-chimney will be roughly 50°C (100°F) warmer than at its top. Such a difference in air temperatures, enhanced by the height of the super-chimney, will produce an incredible airflow. The air from the earths surface will be sucked inside and will travel up at the amazing speed of 300 miles per hour"


    25,000 chimneys will offset Global Warming.
    Each chimney will produce electricity
    Each chimney will induce rain generation in surrounding areas
    Each chimney will transform desert into arable land capable of trapping CO2

http://www.superchimney.org/principle.html

morganism

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Re: Geo_engineering with short space elevators
« Reply #1 on: August 06, 2017, 01:33:13 AM »
Was looking into materials for bagging asteroidal materials in-sutu, and ended up going with mylar or kopek? coated with graphene for flexibility. But they just made graphene coating on a piece of pine by shooting a laser at it, so finding a flexible and uv resistant material doesn't have to be a showstopper here.

There is a LOT of small diameter trees in forests which are a fire hazard problem, if we could direct that cellulose into a carbon sink like a fabric tower, would not be an additional strain on resources except collection and transport.

http://hackaday.com/2017/08/05/3d-printing-flexible-surfaces-out-of-non-flexible-material/#8217;s%20some%20interesting%20work%20shared%20by%20[Ben%20Kromhout]%20and%20[Lukas%20Lambrichts]%20on%20making%20flexible%203D%20prints,%20but%20not%20by%20using%20flexible%20filament.%20After%20seeing%20a%20project%20where%20a%20sheet%20of%20plywood%20was%20rendered%20pliable%20by%20cutting%20a%20pattern%20out%20of%20it%20&#8211

numerobis

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Re: Geo_engineering with short space elevators
« Reply #2 on: August 06, 2017, 03:13:09 AM »
The chimney makes no sense to me. The temperature differential (and pressure differential) exists in open air, but thanks to gravity there's no crazy updraft.

oren

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Re: Geo_engineering with short space elevators
« Reply #3 on: August 06, 2017, 07:22:55 AM »
The chimney makes no sense to me. The temperature differential (and pressure differential) exists in open air, but thanks to gravity there's no crazy updraft.
The web site explains that in open air the rising warm updraft expands horizontally and cools, while in a chimney it cannot do that and therefore has to expand upwards.
I am still bothered by the calculations, as in a 5-km chimney you have a strong pressure/density gradient inside the chimney which the inventor may have neglected. The equations (which I cannot follow) assume one single density inside and one outside, it I read them correctly. Somehow sounds too simplistic.

1. Air Flow Calculations, according to Natural Draft Pressure Calculator 1

q = Π dh2 /4 [ (2 g (po - pr) h ) / ( λ (l pr / dh) + ∑ξ pr ) ]½

where   
dh = hydraulic diameter (m, ft)
λ = D'Arcy-Weisbach friction coefficient
l = length of duct or pipe (m, ft)
g = gravity - 9.81 (m/s2)
q = air volume (m3/s)
po = density outside air (kg/m3)
pr = density inside air (kg/m3)
h = height between outlet and inlet air (m)
∑ξ = minor loss coefficient (summarized and taken as 1)

SteveMDFP

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Re: Geo_engineering with short space elevators
« Reply #4 on: August 06, 2017, 08:00:59 AM »
We've discussed the Super Chimney on this forum before:
http://forum.arctic-sea-ice.net/index.php?topic=568.0

Personally, I don't think there'd be any tendency for net airflow at all.  In natural air flow, updrafts are balanced by downdrafts.  If surface air were always being drawn up, we'd be in a vacuum down here.

Consider the following concept, using the same structure:
Low-density, low-pressure air enters at the top.  As the air descends, it becomes compressed, and thus denser.  As it is compressed, a partial vacuum is created behind it, drawing more air in.  As the descending air becomes denser, it's greater weight per unit volume causes greater gravitaional pull, accelerating the downward force.  Very high downward velocities are obtained thereby.

It's silly pseudo-physics for going down, and I'm not sure it's any less silly going up.

Neven

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Re: Geo_engineering with short space elevators
« Reply #5 on: August 06, 2017, 10:23:01 AM »
As said, there already is another thread on this subject (thanks for digging up, SteveMDFP).
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