Couldn't sunlight concentrated with mirrors be used to desalinate water in the middle east cheaply?

Question

By distilling it without using electricity or any other power source other then the sun. Could this be used to harvest the salt left over from the process as well? Would this work in any bright hot sunny area close enough to the ocean to pipe sea water to it? Wouldn't building enough of these generate enough water be able to turn the deserts of the middle east into gardens and fields bringing prosperiety to the people there and produce enough fresh clean water and food to end world thirst, hunger and help end world poverty? Wouldn't this also work well for Austrailia especially considering the once in a thousend years level drought they've been stuck in and help end terrorism at the same time because it would end those root causes that lead to it?

Wouldn't this also help end economic dependence on selling fossil fuels as well?

Wouldn't this also help with drought prone areas in the western US and help ensure there's enough water for food production if if droughts become very bad?

By bad I mean servere and unrelenting.

Couldn't the mirrors also be placed on rooftops in cities to do this without destroying habitat or leading to greater sprawl?

I think this sort of thing could be sited on top of any city without too much difficulty, or by the ocean, or anywhere it was environmentaly friendly to do in between the ocean and the city that wanted the water. Also, I was thinking about it and I don't see any reason that seawater can't be heated till it turns to steam to power an eletrical generator and produce salt and fresh water all at the same time making any electrical, fresh water, salt production plant more profitble.

mirrors could reflect sunlight to a central prism and focusing mirror that could focus all the heat energy into a single location to generate the temps required..

Answer 1

The other answers show that it is a good idea, and it is already used, especially in the Middle East. The costs are higher than you would expect because sea water is corrosive. Why should we spend precious resources building desalination plants when God gives us so much pure water for free? Did you notice that in most places on earth, all you need to do is drill a hole in the ground and you get clean water? God made the whole earth a desalination plant, and also designed the geologic structure of the earth's crust to deliver a steady supply to most places? Outside of deserts, the only reason there's ever a water shortage is that we waste it, since we don't need to pay God for it.

I just visited Lake Powell in Arizona. The men's rooms have no-flush urinals. A sign above informs that each no-flush urinal saves, on average, 45,000 gallons of water a year. Using that design is a no-cost choice that would make a much bigger difference to our water supply than widespread desalination plants. Save the rooftops for photovoltaic power generation and water heating.

Answer 2

If so, they would be doing it. Here is what they are doing:

There are about 1,483 desalination units operating in the Arabian Gulf countries, which account for 57.9% of the worldwide desalting plant capacity. The dominant plant type is multi-stage flash (MSF) which accounts for 86.7% of the desalting capacity, while the reverse osmosis accounts for only 10.7%. The installed capacity of desalination plants in the Arabian Gulf countries is estimated at 5.76 million m³ per day in total, including 2.98 million m³ in Saudi Arabia, which is approximately half of the total desalination capacity of the Gulf countries (Al-Mutaz 1989). The installed capacity with shares of each process are shown in table 2.10.

MSF desalting has proved to be the simplest, most reliable, and most commonly used seawater system in large capacities.

It has reached maturity with very little improvement in sight. This maturity is expressed in reliable designs of large units up to 38,000 m³ (10 million gal.) per day, long operation experience with high on-line stream factors (up to 95%), confidence in material selection, and very satisfactory water pre-treatment. However, there has been a recent trend towards the use of reverse osmosis in seawater desalination, both for new plants and in connection with the present MSF plants, taking into account the possible reduction in energy requirements and the lower operation and maintenance cost for RO.

Answer 3

Ground level insolation is about 500 W/m^2 maximum. Water enthalpy of vaporization at room temp is about 590 cal/gram. Run the numbers, git. Mirrors only move it around (with Second Law losses subtracted and capital costs accruing interest).

Would you like to generate 1 GW electrical? Yer gonna need 0.3 mi^2 for a nuclear plant or 60 mi^2 for solar collection of any kind. Giggle. If you get your energy from biomass (growing corn) yer gonna need 1000 mi^2. of farmland for your gigawatt.

Answer 4

Possibly.