A fourth method (after reverse osmosis and oil or solar powered distillation) for desalination in Saudi Arabia and other countries with distant deserts and water shortage (like Israel, Lybia and Navada)

Dig a giant subterranian seawater lake in the middle of the desert, (actually hundreds of tunnels) lower than sea level. Above it, on the surface create a brine lake, used for making salt. (In Israel this could be accomlished by digging giant seawater storage tanks under the now dry areas of the dead sea)

The seawater is then pumped at the biginning from the sea but then continues to flow gravity.

For desalination the seawater is pumped up and sprayed onto chambers where it is constantly being evaporated and condensed back with less and less salt. The fresh water is gathered and sent nearby to create a natural-like vegetative green environment in the uninhabited formerly harsh areas.

The brine is gathered on the surface and either evaporated for salt or used as a salt lake for for tourism.
-- pashute, Jun 29 2021

Struggling to understand the energy transfer part of this.

Are you trying to exploit the difference in temperature between deep and less deep?
-- pocmloc, Jun 29 2021



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