[myuncle (OP)]

For a river or aqueduct it’s simple to carry water, gravity is all is needed. But let’s say you want to transport desalinated water from the sea to the desert. If you follow the elevation map, you can basically transport desalinated water from the sea to virtually anywhere. They can use mirrors in a coastal area to heat the seawater, which will evaporate reaching high areas. Make huge funnels to collect the evaporation. And let gravity do the rest. If the pipelines are following the elevation map, water can easily travel anywhere, from Veracruz (Mexico) to Amarillo, from Guelmim area (Morocco) to Agadez (Niger), from Qabilat (Libya) to Ennedi area (Chad), etc., the possibilities are endless.

[Petrochemicals]

Great idea, how do we get the power?

[myuncle (OP)]

Great idea, how do we get the power?

What you mean? Mirrors to heat the water doesn't need electricity.

[myuncle (OP)]

oops, you are right, to transport long distances, the angle would be 0.001°, basically a flat pipeline, so you need power to suck the water at the end of the pipeline. How much power you need? I don't know, have no idea.

[charles1948]

oops, you are right, to transport long distances, the angle would be 0.001°, basically a flat pipeline, so you need power to suck the water at the end of the pipeline. How much power you need? I don't know, have no idea.

On your question of power, wouldn't it be possible to make use of the Earth's axial spin?

For example, suppose we built a pipeline from Antarctica to central Australia.

The centre of Australia is sometimes called its "Dead Heart", because it won't support agriculture to grow living crops.  Due to a lack of fresh water, to irrigate the crops.

Such water could supplied by a pipeline which starts at the centre of Antarctica.  Which roughly corresponds to the. South Pole.  Where the surface of the Earth rotates at minimum speed.   And so its "centrifugal force" is at a minimum.

Then, you put Antarctic snow into the Antarctic end of the pipe.  This results in the following consequences:

1. The snow in the pipe, gets impelled along the pipe by the increasing "centrifugal force" generated by the Earth's
 increasing axial surface spin, as the snow is "flung outwards" to a greater distance from the South Pole.

2.  As the distance from the South Pole increases, the snow gets warmer, and melts into fresh liquid water.

3.  This water eventually emerges at high speed from the Australian end of the pipe.  Where it's sprayed abundantly over the arid ground -  to irrigate it, and thus create new, fertile fields for crops.

Sounds a good idea,  doesn't it?  Or does it contain a fatal flaw?

[myuncle (OP)]

oops, you are right, to transport long distances, the angle would be 0.001°, basically a flat pipeline, so you need power to suck the water at the end of the pipeline. How much power you need? I don't know, have no idea.

On your question of power, wouldn't it be possible to make use of the Earth's axial spin?

For example, suppose we built a pipeline from Antarctica to central Australia.

The centre of Australia is sometimes called its "Dead Heart", because it won't support agriculture to grow living crops.  Due to a lack of fresh water, to irrigate the crops.

Such water could supplied by a pipeline which starts at the centre of Antarctica.  Which roughly corresponds to the. South Pole.  Where the surface of the Earth rotates at minimum speed.   And so its "centrifugal force" is at a minimum.

Then, you put Antarctic snow into the Antarctic end of the pipe.  This results in the following consequences:

1. The snow in the pipe, gets impelled along the pipe by the increasing "centrifugal force" generated by the Earth's
 increasing axial surface spin, as the snow is "flung outwards" to a greater distance from the South Pole.

2.  As the distance from the South Pole increases, the snow gets warmer, and melts into fresh liquid water.

3.  This water eventually emerges at high speed from the Australian end of the pipe.  Where it's sprayed abundantly over the arid ground -  to irrigate it, and thus create new, fertile fields for crops.

Sounds a good idea,  doesn't it?  Or does it contain a fatal flaw?

I suppose the snow won't melt, clogging the pipe. It would be easier to melt the snow in Antarctica using wind power, then transport it.

[myuncle (OP)]

I wonder also what would happen if you place tall cranes in strategic points. There are tall mountains even in the desert, Mount Koussi in Chad for example is 3415 m tall. But probably the ice is not enough, and when it forms it stays in plateau areas, staying almost useless. Some of the tallest cranes are about 250m tall. Imagine you put a 500m tall crane on the top of Mount Koussi, you would reach 4000m, and probably ice formation would become huge and constant.

[myuncle (OP)]

Another idea: you tether flying fridges in the desert. Fridges are solar powered, and are obviously open, so the ice can drop down. You fly them using anything: kites, airships, hot air balloons. Everything is tethered to the ground. If the fridges make too much ice, they will become too heavy for the kites/airships. As a result things start going down, allowing the ice to melt. Once the ice is gone, the kites/airships will go up again, and the cycle repeats itself.

[Kryptid]

Another idea: you tether flying fridges in the desert. Fridges are solar powered, and are obviously open, so the ice can drop down. You fly them using anything: kites, airships, hot air balloons. Everything is tethered to the ground. If the fridges make too much ice, they will become too heavy for the kites/airships. As a result things start going down, allowing the ice to melt. Once the ice is gone, the kites/airships will go up again, and the cycle repeats itself.

How do you get the water into the refrigerators so that they can make ice?

[evan_au]

The snow in the pipe, gets impelled along the pipe by the increasing "centrifugal force" generated by the Earth's increasing axial surface spin, as the snow is "flung outwards" to a greater distance from the South Pole.

- We normally measure height above sea level. Liquid water will flow naturally if it moves to a lower height above sea level, (with a slope of 1 in 50 or greater).
- The reason this works is because sea water already feels this "centrifugal force", so any flow possible from this mechanism has already been utilized by sea water, when setting the sea level.
- The same effect also affects rocks (but much more slowly)
- That is why the Earth's diameter at the equator is larger than the diameter through the poles, by about 40km
See: https://en.wikipedia.org/wiki/Earth

[myuncle (OP)]

Another idea: you tether flying fridges in the desert. Fridges are solar powered, and are obviously open, so the ice can drop down. You fly them using anything: kites, airships, hot air balloons. Everything is tethered to the ground. If the fridges make too much ice, they will become too heavy for the kites/airships. As a result things start going down, allowing the ice to melt. Once the ice is gone, the kites/airships will go up again, and the cycle repeats itself.

How do you get the water into the refrigerators so that they can make ice?

I don't know how fridge work, but doesn't a cold surface (drops on a cold coke can for example) collect water from the air?

[Petrochemicals]

they can make ice?
Report

Mirrors, solar power etc will gather some energy, but to evapourate, condense and transport the quantities of water you are suggesting will require much energy. I should imagine that desalination plants are as efficient as can be at present.

The USA would be a good place to start, after all they are rich and have deserts that they try to irrigate.

[wolfekeeper]

On your question of power, wouldn't it be possible to make use of the Earth's axial spin?

For example, suppose we built a pipeline from Antarctica to central Australia.

No. To a first approximation the Earth's surface is basically an equipotential, the crust sits on a liquid core, so it tends to slide around to even out the potential energy everywhere, and the sea does something similar. There's an equatorial bulge due to the spin, and that's why.

You have to rely on variations of the topography away from mean sea level.

[Bored chemist]

There is one interesting idea raised here.
Water vapour is less dense than air.
If you had a pipe from the coast to the arid region you could allow water vapour to run up the pipe, and then cool it when it got to the place where you needed water.
It's usually cold at night...

[wolfekeeper]

I don't see that cooling is much of a problem. Indeed, a major issue would be the walls of the pipe would tend to condense the water vapour, so, much of the water would never make it to where you want it. You'd have to insulate the walls of the pipe up to the highest point to maximise water transfer. From there it will naturally condense and you could rely on the condensate flowing down hill.

The real problem is that water has a stupendously high latent heat of vaporisation. You'd probably have lower system costs to just run a desalinator and a pump, otherwise the heat exchanger to take the sunlight and evaporate the water is likely to be extremely expensive.

edit: I suppose really you don't need mirrors, you just need solar thermal collectors, like people put on their roofs to make hot water, a few square kilometers of that, and some pumps to circulate water around to get rid of the salinity.

[alancalverd]

Free desalinated sea water is called rain. The trick is not to live where there isn't any.

[Bored chemist]

Free desalinated sea water is called rain. The trick is not to live where there isn't any.

On a per capita basis, that precludes living in the SW of the UK.

[alancalverd]

Somerset >1500 mm per annum/956,000 . Cambridgeshire < 600/847,200, roughly half the per capita rainfall of the southwest.

But overall, it's pretty comfortable everywhere.

The trick is to use appropriate agriculture, as has been done for the last several thousand years: dairy to the west, arable to the east, and sheep where nothing else works..

[Bored chemist]

Free desalinated sea water is called rain. The trick is not to live where there isn't any.

On a per capita basis, that precludes living in the SW of the UK.

I should, of course, have said "bits of the SE of the UK".  (It was late...)

Somerset >1500 mm per annum/956,000 . Cambridgeshire < 600/847,200, roughly half the per capita rainfall of the southwest.

Thanks for that, now, if you could do the same calculation for Greater London and, as an example of somewhere quite dry, Arabia.

You may find this data on population density helpful
http://www.citymayors.com/statistics/largest-cities-density-125.html

[Petrochemicals]

Of course you could utilise the steam contraction and cold night time desert temperature of the desert. That would be convection.

To make it work you would need a large volume to provide the piston. Desalinate by the ocean using the sea as coolant, put it into a tank , have the contraction tank in the desert full of steam and hopefully by morning you would have fresh water. The volumes needed for large agriculture would not be feasible though, even the Colorado river is defeated by the sheer quantity needed.

Heat exchangers desalination plants, solar and pumps would  be far more rational.