Pulling water out of thin air

MIT scientists have devised a way to distill water out of air, even air without much humidity in it, using no energy other than the sun’s.

The team uses a box filled with a powdery material that absorbs air into its microscopic pores. When the box is heated – by sitting in sunlight, for example – water molecules in the trapped air are released and then condensed.

Current air-to-water systems need an artificial energy source, such as a generator, and often include a refrigeration cycle.

The prototype device can produce an eight-ounce glass of water in an hour, using air with 20 to 30 percent humidity, or several liters (a gallon or more) in 12 hours.

The research team is working toward a low-cost commercial product that could scale from home-sized to irrigating farm fields.