Re:Why Is Desalination So Difficult?
by nine_k on Wednesday July 05, 2023 @07:00PM
(#36608397)
This is correct.
But we seem to have colossal amounts of essentially free solar energy, and that energy already evaporates large amounts of sea water. We just don't capture it well.
Imagine building a pipe that stands above shallow tropical coastal waters. Make the bottom of it into an almost flat funnel to cover more water surface, using transparent plastic or even glass. Now all the evaporated water and hot air go into the pipe.
Build the pipe a kilometer tall. Humans have adequate technologies already, and the pipe does not need to be bearing much internal load, unlike Burj Khalifa or World Trade 1.
At 1km, the air is cool enough. The hot air will shoot upwards, cooling on its way up and releasing fresh water. Lightweight collector pipes will bring it down into a reservoir. The remaining dampness of the air will help it produce clouds, and thus shadow, over the land.
With a tall enough pipe, we could even generate electricity by putting a turbine inside.
Why are we not building it? It's expensive, and most (sub)tropical countries that lack water are poor. They are also politically unstable, and such an installation would be a high-value military and terrorist target.
Maybe Singapore or Dubai would some day dare and build it. (California, unlikely; it would never pass an environmental review.)
But we seem to have colossal amounts of essentially free solar energy, and that energy already evaporates large amounts of sea water. We just don't capture it well.
Imagine building a pipe that stands above shallow tropical coastal waters. Make the bottom of it into an almost flat funnel to cover more water surface, using transparent plastic or even glass. Now all the evaporated water and hot air go into the pipe.
Build the pipe a kilometer tall. Humans have adequate technologies already, and the pipe does not need to be bearing much internal load, unlike Burj Khalifa or World Trade 1.
At 1km, the air is cool enough. The hot air will shoot upwards, cooling on its way up and releasing fresh water. Lightweight collector pipes will bring it down into a reservoir. The remaining dampness of the air will help it produce clouds, and thus shadow, over the land.
With a tall enough pipe, we could even generate electricity by putting a turbine inside.
Why are we not building it? It's expensive, and most (sub)tropical countries that lack water are poor. They are also politically unstable, and such an installation would be a high-value military and terrorist target.
Maybe Singapore or Dubai would some day dare and build it. (California, unlikely; it would never pass an environmental review.)