Saw this and thought it interesting. Looks like something that could be "home brewed easy". Less energy than RO. Sorry for the length but I removed a lot.
Bob
This machine makes drinking water from thin air
By
Giovanna Rajao and
Michael Schwartz, CNN
April 24, 2014 -- Updated 1002 GMT (1802 HKT) | Filed under:
Innovations

Israeli company Water-Gen has developed a device for extracting
drinking water from air. It's already being used by the military, but Water-Gen says its future is in civilian uses.
HIDE CAPTION
Water for the battlefield and beyond
STORY HIGHLIGHTS
- Israeli company has developed device for extracting water from air
- It says its water generator is more energy efficient than others
- Its technologies are already used by the military in seven countries
Tel Aviv, Israel (CNN) -- Water. A vital nutrient, yet one that is inaccessible to many worldwide.
The World
Health Organization reports that 780 million people don't have access to clean water, and 3.4 million die each year due to water-borne diseases. But an Israeli company thinks it can play a part in alleviating the crisis by producing drinking water from thin air.
Water-Gen has developed an Atmospheric Water-Generation Units using its "GENius"
heat exchanger to chill air and condense water vapor.
"The clean air enters our GENius
heat exchanger system where it is dehumidified, the water is removed from the air and collected in a collection tank inside the unit," says co-CEO Arye Kohavi.
"From there the water is passed through an extensive water filtration system which cleans it from possible chemical and microbiological contaminations," he explains. "The clean purified water is stored in an internal water tank which is kept continuously preserved to keep it at high quality over time."
Several companies tried to extract water from the air ... But the issue is to do it very efficiently.
Arye Kohavi, co-CEO Water-Genius
Energy efficient
Capturing atmospheric humidity isn't a ground-breaking invention in itself -- other companies
already sell atmospheric water generators for
commercial and domestic use -- but Water-Gen says it has made its water
generator more energy efficient than others by using the cooled air created by the unit to chill incoming air.
"Several companies tried to extract water from the air," says Kohavi. "It looks simple, because
air conditioning is extracting water from air. But the issue is to do it very efficiently, to produce as much water as you can per kilowatt of power consumed."
He adds: "When you're very, very efficient, it brings us to the point that it is a real solution. Water from air became actually a solution for drinking water."
The system produces 250-800 liters (65-210 gallons) of potable water a day depending on temperature and humidity conditions and Kohavi says it uses two cents' worth of electricity to produce a liter of water.
Civilian uses
Developed primarily for the
Israel Defense Forces (IDF), Water-Gen says it has already
sold units to militaries in seven countries, but Kohavi is keen to stress that the general population can also benefit from the technology.
He explains: "We believe that the products can be
sold to developing countries in different civilian applications. For example in
India, [drinking] water for homes is not available and will also be rare in the future. The Atmospheric Water-Generation Unit can be built as a residential unit and serve as a perfect water supply solution for homes in
India."
Kohavi says Water-Gen's units can produce a liter of water for 1.5 Rupees, as opposed to 15 Rupees for a liter of bottled water.