Dear Brian Whatcott:

On Sep 21, 3:35 pm, Brian Whatcott wrote:
You've heard all about distilling water, and you've
heard all about reverse osmosis, but you haven't
heard about low-cost, low energy stills: they are
brand new.

Briefly:
Take one forty ft vertical tube filled with saline.
Take one forty ft vertical tube filled with fresh water.
Connect them with a little engineering help - at
the top.

The boiling point of water at sea level pressure is
about 100 deg C

The boiling point of water at the top of a sealed
40 ft column of water is near ambient. So, it
doesn't take much heat to boil the brackish water,
and have it pass to the fresh column where it is
slightly cooled to hold the near vacuum conditions
at the boiling level.

[An engineering effort of a U of Utah group I think]

There are ship-board distiller units that use an engine to pull a
vacuum, and the engine's waste heat to boil that water, to generate
drinking water. A little shorter...

David A. Smith