[horsebox]

An idea I've been mulling over for years now is to setup a network of solar stills in the Sahara desert in order to desalinate sea water which will then be pumped (by solar powered pumps) into a network of canals which will distribute the water so that large areas of the desert along the coastline can be irrigated and converted from a barren, infertile wasteland into agricultural land and forest area. Not sure what the BP of saturated salt water is but I'd say sea water boils at around 120C. This temperature could easily be reached in the scorching Saharan desert but it takes time to heat the water so the process would be quicker under vacuum.

I haven't thought of all the fine details of this idea yet. If you had to pull this off, how would you go about it? The first thing I'd do is setup pumps to pump sea water through a 1 way valve into some kind of reservoir so that there will be a steady supply of feedstock even if the pumps break down temporarily. I'd power these pumps by solar cells. Next I'd dig shallow, wide area chambers that are covered by a sheet of glass. This would be where the water is heated to boiling temperature. I'd connect these chambers up to distillation chambers where the water will evaporate and the vapour will be separated from the feedstock before being condensed. These distillation chambers could be put under vacuum easily. The rest is all pretty straight forward, just canals, solar powered pumps, one way valves and reservoirs.

[vmelkon]

Another method of producing electricity is to have pools of salt water. The bottom can reach high enough temp to boil clean water. The vapor can drive a turbine. I have read about it but never seen this.

[billnotgatez]

what do you do with the toxic waste

[mattfred]

Vacuum pumps are very expensive and high maintenance, so if your goal is to make this process cheap and low maintenance, the vacuum part is a little bit much.

There's a lot of information and projects attempting similar things if you really want to get involved:

http://www.popsci.com/environment/article/2009-06/solar-collectors-covering-03-sahara-could-power-all-europe