Author Topic: Earth oceans, space ocean, pipes, and elevator  (Read 2052 times)

Offline gbaikie

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Earth oceans, space ocean, pipes, and elevator
« on: 07/18/2013 06:28 pm »

linked from:
http://moonandback.com/2013/07/14/an-elevator-to-space-markus-landgraf-at-tedxrheinmain/

In this TED presentation on space elevators, it mentions some great things that people on Earth could have if they only had space elevator.
I was encouraged that someone was mentioning some of expansive possibilities if we could cheaply get into space.
I don't think we need technology of space elevator to get there, but it is good if the public is exposed to future possibilities, once the costs to get into space has been lower [significantly], and enabling more access to space.
A line or two mentioned [in passing] in presentation concerned the inability of earth's surface supporting extremely high compressive forces [a given reason for space elevator having to use tensional strength rather than compressive loads].

Anyways, it made me wonder. What can support more compression load, ocean or land surface?
It might be that land would have the advantage.
The reason I wonder about it, is that with ocean one can have buoyancy, and it seems on solid ground you don't normally get buoyancy. Though the frictional force may be more useful in comparison.


But once got wondering about this, the next question was what actually would be maximum compressive load on land.
And not sure there is one.
Rather it seems the limitation is costs. Because obviously if one wanted a narrow tower, there would be problems, but if it was made really fat and tapered it and using lower density material which had high compressive strength, and using cubic miles of material [of any kind] drives cost up.


So wondered about idea that in oceans could bear more compressive force than land. Or, that oceans might good place for anything tall and large.

So first want go over a concept, which I don't know what it's would be called. Probably, some term for it- I don't know it.
It's everyday thing.

So, take two cylinders [stove pipe] and connect them with something flexible, say rubber. Connect the rubber to both cylinder and so it's air tight. And have the ends of cylinder capped.
So without air pressure, this is not rigid. But once air pressure is added, it becomes a more rigid structure.
So, air pressure pushes the two cylinders apart. And if put this cylinder vertical, one has tensional force making rubber rigid and compressive force of earth gravity.
Or same thing as having some inflatable dome on the moon and putting bunch regolith on it- the air pressure holds up massive weight of the ceiling [which could be unsafe if one loses the atmospheric pressure of the dome].
The main factor involved would be tensional rather compressive loads on the structure and without the atmospheric pressure lifting (meters of regolith) one would have compressive load on base of dome wall as being the significant factor.
So, the rubber between the cylinders, is quickly to show, that if cylinder is vertical and under pressure it will have both compressive and tensional loads.

Now, related large structures, a problem with big volumes is high pressure require a very strong structural strength. Unless you are surrounded by a high pressure environment- such as is found on Venus, gas giants and Earth's ocean depth.
1000 meters under ocean is fairly high pressure environment [100 atm-1470 psi]. With deepest parts of our ocean is several km deep [5 to 10 km].
So with air pressure of 1480 psi at 1000 meter under water, it requires little structural strength to contain it. And with a number of spaced bulkheads, one can have varying air pressure depending on depth of water, and requiring a moderate amount structural strength.
And like any submarine, one can control it's overall buoyancy- make go up or down- by letting in ocean water and expelling it.

What I call a pipelauncher [a type of oceanic mobile rocket launcher
for space launch vehicle] is a long large pipe with one bulkhead at the top of it. In way, maximizing the control of a large amount of buoyancy.

A pipelauncher could also "work" by having more than one bulkhead. Well, normally for safety one could include a section of pipe above this single bulkhead which always sealed and under a modest amount pressure [or it could filled with some floatation foam] so that such floatation makes it an "unsinkable ship".
But that sort of thing is merely a detail of design, but I meant is one could have multiple bulkhead related how a pipelauncher is powered or moves and operates- how it functions.
And as I was saying above, at depth one can hold a tremendous amount air pressure with little structural strength as one is in a high pressure environment.
And one aspect about making a pipelauncher go up is you need a lot of air in a very short period of time [seconds]. So, it's an alternative or a addition to using liquid air and heating of burning kerosene or methane [like a flame thrower] to get a high volume of air within short period [fairly warm air, say 100 to 200 C].

So the two bulkhead variant could be to store high pressure air at deeper ocean depth.
So, a big pipe, say, 20 meter in diameter and 1 km tall [long]. You have the bulkhead at top, and another one at say 900 meter down or 100 meters from the bottom.
Normally, a pipelauncher needs an open end at bottom to allow water to move freely. So with this, you put holes or slits above the second bulkhead, in order to allow water to enter and leave.

At 900 meters under water it is 90 atm [1323 psi]. And the bottom of pipe is open, the amount of compressed air could say 95 meters [leaving 5 meters of "safety margin or play]". So at 995 meter, 99.5 atm [1462 psi].
So at the 900 meter level, it's over it environmental ocean pressure:
1462 - 1323 psi which is 139 psi.
So need structural strength which can withstand pressure of about 150 psi. Which is not too difficult- the pipe wall of bottom 100 meter, could say, 50% or 100% as thick as rest of it.
So a volume of 95 meter length at 20 meter in diameter and at around 1400 psi.
Or double volume and 1/2 the 1400 psi. Fills a volume of 190 meter by 20 meter diameter at 700 psi.
It's going to need somewhere around 100 psi for entire 1000 meters.
So repeating same thing: 380 meters at 350 psi. 760 meters at 175 psi. And 1520 meters at 20 diameter at 87.5 psi.
So it is roughly about what needed for the 1000 meter long pipe.

There are some problems, the air starts cold [ocean temperatures at this depth above 0 C, but close to it].
And cools further when you lower the pressure.
Hmm. This actually is pretty powerful refrigerator. But one does have a lot of relatively warm water which could easily used. You could probably use warmer top of ocean, to the warm air to 60 or 70 F [15 to 20 C]. And one may cool enough ocean water nearer the surface, so it falls fairly fast [might be useful or not].
[If using liquid air, you could even make liquid air at the site. You make it using by energy, and the pipelauncher is heat engine which could be used. But probably not- simpler and cheaper to simply buy bulk liquid air.]

So, using small diameter pipe, say 1 foot in diameter [and it could be part of structural component of pipelauncher] which has thick enough and strong enough, having wall thick enough with diameter to handle the 1462 psi.

So say strength yield of 40,000 PSI of typical steel at 12" outer diameter. Say 1" thick walls with at safety factor two. It has operational max pressure of 3300 psi.
Ok, so make closer to 1/2" and it's 1700 psi.
So with few of these pipe, one bring the 1462 psi up + 600 meters. So at a shallower depth and "bubble it" thru water and thereby warming air and cooling the water.
Water has very high specific heat- Per 1 C temperature 1 ton of water warms 4 tons of air.
One could expect an intense amount of bubbling and churning of water. And you would probably bubble the air, vague similar to huge fish tank bubbler, so that the water exchanges heat- if larger air bubbles [or one big bubble] it will very poorly exchange heat.

I think open ocean is good location to launch rockets. But also think in the future a lot of people could live on the ocean. And I think just like the space environment the main problem is accessing the ocean.

For any human settlement on the ocean the main thing needed is to have access to cheap energy.
[I am not believer in cheap earth based solar {or wind energy}]
though ocean could be thought as good location for such forms of energy production- assuming one believes in that sort of thing.

Hydro power is great way to make energy, but not really an available option with the ocean. {Nuclear energy is option.}
Even though not a believer in the space elevator opening space frontier, I think that space elevator could useful, particularly after space frontier is opened. So I think in more distance future, there could very well be space elevators. And I think space elevator base part belong on oceans.
One thing I think a space elevator could be useful for is to transmit  electrical power via a conductor from the space environment.
So solar energy may be a source of electrical power at ocean areas, but this solar power is harvested from the space environment and is transmitted to ocean locations. Or rather using an elevator perhaps this energy will be transmitted without wire [microwave or laser beaming].
But even so, one use ocean receiving stations to collect this beamed energy.

So it's seems, that  if and when solar energy is harvested in space environment at same time you going to have opportunity to have cheap electrical power available in areas in the ocean.

What else? I am not sure about OTEC as way to generate electrical power:
http://en.wikipedia.org/wiki/Ocean_thermal_energy_conversion

I seems like could too expensive [may too low of energy density as is solar and wind energy] but on plus side it seems it fundamentally has one advantage, it can provide constant and therefore dependable power.
Which is one of solar and wind energy biggest disadvantage.

Another thing about OTEC is it's in a fairly safe environment. And this also applies to all large structures in the ocean, but with OTEC a lot of it's infrastructure is under the ocean surface and anything below the ocean thermocline-  100 meters below the ocean surface-  is very stable environment.
So a submarine passes effortless thru hurricane region while surface ship like an air carrier is battling the weather.
Now, of course the submarine operate in a hostile environment, arguably more difficult than lunar surface and most other places, but under the water it is a relatively unchanging/constant environment.
So you don't have the hurricanes, floods, tornadoes, earthquakes, tsunami, fire, crime, riots, warfare, lightning, and whatever.
And in terms of ocean surface structures if structure is big, it could be safer than living on a beach. Mainly because a beach houses, aren't designed to function in water, and the water can invade the area, so the : hurricanes, floods,tsunami, high tides and storm surge, and the others things.

Some FPSOs can survive well in a hurricane. FPSOs:

"A floating production, storage and offloading (FPSO) unit is a floating vessel used by the offshore oil and gas industry for the processing of hydrocarbons and for storage of oil. "
http://en.wikipedia.org/wiki/Floating_Production_Storage_and_Offloading

So something like this:
http://en.wikipedia.org/wiki/File:FPSO_Sevan_Voyageur.jpg
It's vaguely resembles a pipelauncher. The Sevan Voyageur has bigger diameter [78 meters in diameter, 32 meters high] and much shorter. 
But more similar my idea of kind a large ocean structures which can used as living areas for human population on the ocean.
So:
"Voyageur Spirit has continued to demonstrate the suitability of the Sevan design for operations in harsh environments and at the end of 2009 it had achieved 398 days at sea without any lost time incidents."
http://www.sevanmarine.com/index.php/component/content/article/41/16-voyageur-spirit
Displacement at
18m draft:       55,000 mT
Deck area capacity:       5,000 mT
Deck area:       3,200 m2
Accommodation:       54 persons
Crude storage
capacity:       270,000 bbls/43,000 m
[It makes a living storing offshore oil.]
Revenue    US $255.9 million (2010)
Operating income    Decrease (US $33.7 million) (2010)
Profit    Decrease (US $156.8 million) (2010).
Obviously design to hold and process oil, but could something like
it make revenue as residential or commercial real estate?

Now in order to have many people living in ocean there needs to be a source of cheap energy.
And need means of transportation.

Elon Musk was recently in news, again. He wants to do fast transportation.
I imagine looked at the proposed Californian bullet trains, and thought they were far too slow and expensive. And one could go much faster and use less energy and perhaps even cheaper. As being the inspiration. Example news story:
http://thenextweb.com/insider/2013/07/15/musk-will-publish-designs-for-hyperloop-a-transport-system-faster-than-the-bullet-train-on-aug-12/

But if you can go from LA to SF or LA to NYC.
It seems to me it's cheaper for such system to travel under water rather than underground [or above ground].
Say it's 150 meters under water. So 15 atm [220 psi].
Need something with good compressive strength- so, concrete.
And you going to need concrete underground or above ground.
And don't need to dig or occupy surface land- which is in use. And has other traffic [cars and trains, etc]
Also another problem with above ground, is temperature changes. Under ground or under water on has fairly constant temperature. Therefore miles of it, is not going to do much expansion or contraction. And the ocean tends to be fairly level and 100 to 150 meter under water could be very level [and can made really level- one could adjust for tides, so a laser beam level is possible- though over long distance you would want a slight curve].
So you do a train from LA to Tokyo. Or NYC to Paris.

But my point is ocean in future could have very fast means of transportation. 

So this is Advance Concepts and talking mostly about distance future [probably a impractically too distant future] and how opening space frontier could change how live on Earth in terms of more use of ocean environment.

Nearer term, I think pipelauncher could used as a launch pad in ocean.
I also think that coastal regions could used as suburb of coastal cities. Something requiring city and state planning.

And this post is probably far too long.
« Last Edit: 07/19/2013 12:23 am by gbaikie »

Offline kch

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Re: Earth oceans, space ocean, pipes, and elevator
« Reply #1 on: 07/18/2013 06:47 pm »
... this post is probably far too long.

Could be ... ;)

Offline cordwainer

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Re: Earth oceans, space ocean, pipes, and elevator
« Reply #2 on: 07/18/2013 08:54 pm »
Yes, far too long couldn't read all of it like reading Tolstoy but with maybe a few less grammatical errors. That being said an ocean based pipe launcher could be used for transmittal of other forms of energy. the pipe or surrounding pipes set side by side with the launch pipe could be used as vortex engines to drive turbines. The artificial island created as a floatation bulkhead would be the better place for solar and solar thermal stations. Concentrated solar heating could be used to run a Stirling engine by piping a heated fluid towards the bottom of the pipe launcher to react with cold seawater. Tidal power turbines could also be built into the pipe launcher as well. The pipe launcher could also be used as a base for undersea surface mining and seawater materials extraction.(like uranium and deuterium)

Offline grondilu

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Re: Earth oceans, space ocean, pipes, and elevator
« Reply #3 on: 07/18/2013 10:05 pm »
Around 16'  :

« All we have to do is make these contact surfaces bigger.  Because the force to put two fibers apart is proportional to the contact surfaces.  And how can you make those bigger?  You make longer fibers.   And then you can twist them even more and the contact surface grows in proportion with the length of the fiber.  And at some point you would need more force to pull two apart, than you would need to rupture one. »

I had no clue.   That sure gives some hopes.
« Last Edit: 07/18/2013 10:06 pm by grondilu »

Offline gbaikie

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Re: Earth oceans, space ocean, pipes, and elevator
« Reply #4 on: 07/18/2013 11:22 pm »
Around 16'  :

« All we have to do is make these contact surfaces bigger.  Because the force to put two fibers apart is proportional to the contact surfaces.  And how can you make those bigger?  You make longer fibers.   And then you can twist them even more and the contact surface grows in proportion with the length of the fiber.  And at some point you would need more force to pull two apart, than you would need to rupture one. »

I had no clue.   That sure gives some hopes.

Yeah, that has been the problem with getting the stronger material.
It's getting the longer nanotubes and making them cheap enough [having a process of making them fast enough].
But there is no shortage of market for this kind of super material.
It would be used for bridges [and lots of other applications worth billions of dollars].
It seems to me very unlikely that space elevators are going to be a driver in this development.

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