Long straight 5 mile tall pipe that pumps cool air from the upper atmosphere to the surface
Posted by New_Elk_5783@reddit | CrazyIdeas | View on Reddit | 40 comments
The temperate 5 miles up in the air is very cold. So we have a lot of free cold air up above. We just need to pump it down to the surface and we get (practically) free AC.
A few points of consideration -
1) The pipe needs to be very insulated so it doesnt absorb heat from the surroundings
2) The pump needs to be strong enough to pump air from low pressure at the top to high pressure at the bottom.
3) The pipe needs to be strong enough to witshtand its own weight, wind, temperature changes, natural disasters etc
CatchAllGuy@reddit
As a kid i had similar idea, upper atmosphere is low pressure; why not put up a tall enough pipe and upper atmosphere will suck up the higher pressure and higher temperature ground air to the upper atmosphere đ
superSmitty9999@reddit
All they naysayers need to shut up and can we get some VC funding for this man
jacksmashsteel@reddit
Hot air going up a pipe is a pipedream
ChinaShopBull@reddit
Youâre working with the adiabatic lapse rate. I donât think itâs really that cold after you compress it to one atmosphere.
Ok-Active-8321@reddit
Its not. This is why the Santa Ana winds in California are so hot. Cold air at the top of the mountains heats up as it moves down the mountain and is compressed.
Worth-Wonder-7386@reddit
Once you compress it, you jsut have normal air. This is not really a source of cooling.
hastag420bluntz@reddit
So what about doing it in reverse? Put the pipe up and hook up a vacuum pump. Exhaust the atmosphere up high so it lowers the pressure and makes it cooler at ground level.
Stannic50@reddit
You'd have warmer than ambient temperature air after compression (something around 47C). This is not a source of cooling because it's a source of heating.
Although I guess you'd be forcing air from down here farther up and therefore cooling it as it decompressed.
ApolloWasMurdered@reddit
What if we compressed it more than necessary, put fins on the pipe to dump that heat as the air travels down, then let it return to atmospheric pressure at the bottom?
Stannic50@reddit
That's just air conditioning with extra steps.
BugRevolution@reddit
OP invented a really inefficient heat pump.
July_is_cool@reddit
Or move to the mountains?
LunaticBZ@reddit
Alternative idea, with building 5 miles up. You'll want active supports to hold the thing up in the air.
Have good insulation around the supports for the first 3 miles or so and have a radiator at the top.
Then you dont need to suck air down. Your support is constantly moving whatever material your using to support it, up to where its cold and back down again.
Questo417@reddit
Make a gigantic piston that can move your house to the upper atmosphere, where you can open the windows, let it cool off, and then drop it back down to the ground.
What could possibly go wrong?
LunaticBZ@reddit
It worked in the show the Jetsons. You might be onto something here.
SonicLoverDS@reddit
How long do you think it'll last before a bird gets sucked in?
New_Elk_5783@reddit (OP)
Obviously there's gonna be a grill at the top end.
SonicLoverDS@reddit
A bird getting trapped against the grill by suction isn't much better than a bird getting sucked down the pipe.
Questo417@reddit
But it is tastier
m00ph@reddit
Not all that many birds at 25k', though you'll get a few
BugRevolution@reddit
Grill, not grille
FredOfMBOX@reddit
Ooh! So now the air smells like delicious grilled steaks!
shaggs31@reddit
How many birds are 5 miles up?
truethug@reddit
Do birds fly 5 miles up?
m00ph@reddit
Yes. Not many, but they do.
myfufu@reddit
I mean, sometimes you hear about a bird at 26,000 feet, but it's pretty rare! đ
TedW@reddit
Guinness world records says birds have been hit at 37,000 feet which seems absolutely insane to me.
Too_MuchWhiskey@reddit
Google 'SB Cool Tower'... similar idea on a smaller scale.
axloo7@reddit
Hmm..... Why not do the same underground?
Even better fill it with a liquid solution and use a heat pump so that you can extract even more cooling from the rock.
Wait that's just geothermal.
PilotBurner44@reddit
There's a reason it's cold up there, and that reason is lack of pressure on expanding air and less radiation heat from the ground. By the time you "pump" it down, which is effectively compressing it, you lose all that "cool" portion. You'd still have a slight temperature difference due to lack of radiation heating, but by the time you add in friction, lack of efficiency, and a bunch of other heat additives, it'll likely be warmer than the surrounding air.
therealCatnuts@reddit
We have cold air always, everywhere, only 5 feet below the surface.Â
Mediocre-Yoghurt-138@reddit
OP chased a lead in the wrong direction to historic proportions.
mutexsprinkles@reddit
Or you send hot air up, run turbines and then use a heat pump to do the cooling.
https://www.nationalgeographic.com/history/article/140416-solar-updraft-towers-convert-hot-air-to-energy
drivera1210@reddit
Look up a solar chimney. The pipe does not need to be that high.
chaz_Mac_z@reddit
If you Google adiabatic compression or expansion, you find a curve where, as volume for a given amount of air goes down, temperature and pressure go up. Adiabatic means, no heat transfer occurs. The net result of bringing air from high altitude will be air at least as hot as the air at ground level. Probably hotter, since you have to add energy to move it.
unwittyusername42@reddit
You would have to protect it from riff raff - I would suggest a coyote with an anvil at the top. It's just as practical.
S14Ryan@reddit
âPractically free ACâ is interesting. The amount of heat the vacuum pump motor would generate would be more than the amount of cool air it would be able to pull. It takes a lot of energy to pull air into a vacuum, and to move a significant volume would require a significant amount of energy. I have booster screw compressors that take pressure from 10âhg to 10 psi and they might move 180cfm of refrigerant, probably roughly equivalent cooling of a 4 ton (4HP) air conditioner if the air itâs sucking is still -40 when it reaches the surface. That compressor uses a 100HP motor to turn. Sure maybe a centrifugal compressor might be able to do it more efficiently but these things do not do well with any amount of contamination getting into them. Letâs say your discharge air is 1psi so it moves air better, itâs not gonna make it 25x more efficient, so the heat generated from turning the motor will still be significantly more than what it is able to pull from the atmosphere.
Current_Speaker_5684@reddit
Maybe easier to radiate or reflect heat back out.
CatnipPetal@reddit
don't beg for warmth. protect your peace fr
New_Elk_5783@reddit (OP)
NPC ahh response