Researchers build machine to extract drinkable water from air

What's happening: Researchers at MIT and several other institutions published a paper earlier this week describing how they were able to significantly boost the output of a prototype water-harvesting device.

• The original design harnessed temperature differences within the device to draw in moisture from the air at night and release it the next day. But its utility was limited because it required specialized and expensive materials called metal organic frameworks.
• The new design adds a second stage and makes use of a more common material called zeolite, doubling its capacity to generate water.

Details: While other harvesting technologies that can draw water from fog or dew exist, they generally require humidity levels of at least 50%, if not much higher.

• The new design, by contrast, can work with humidity levels as low as 20%, good enough to operate on an average day in a desert city like Phoenix.

The catch: Even the improved system can still only produce 0.8 liters of water per square meter per day, while humans need at least 2.5 liters per day to survive.