This Amazing Solar-Powered System Can Draw Potable Water Out of Even the Driest Air
MIT researchers have developed a system that can extract drinkable water directly, using heat from the sun or another source.
According to the World Health Organization, one out of every three people in the world lacks access to safe drinking water. In many regions, that is the result of pollution or biological contamination making the water unsafe, but in deserts it is often just a simple absence of water. Unfortunately, it is both impractical and unsustainable to simply ship or pump water to these areas. To provide long-lasting change, people living in especially arid regions need to be given the ability to produce their own drinking water. This solar-powered system, developed by engineers from MIT, is able to draw potable water out of even the driest air in order to provide that.
When you hear the term “solar-powered,” you probably picture some device with a solar panel attached to it. But, in this case, the system isn’t electronic at all. It simply takes advantage of the sun to provide a temperature differential that can be utilized to coax moisture out of the air. If you’ve ever watched survival-focused TV shows like Man vs. Wild, then you’ve seen how clear plastic sheets can be used to collect condensation. The most efficient way to do that is to place the sheet over something relatively wet, like a green, leafy plant. That works just fine in humid areas where moisture is in abundance, but doesn’t help those in arid environments. That’s why this system utilizes special materials that can wick and then collect moisture, even when the air has very little humidity.
In the daytime, the average relative humidity of the Nevada desert, for example, is around 20 percent. That’s far less than somewhere like the Oregon coast, where it is around 80 percent. But even air with 20 percent humidity contains some moisture, and it generally increases quite a lot at night. This system has a special adsorbent (not absorbent) material that, after being heated during the day, collects moisture on its surface from the relatively humid night air as it cools. During the day, as the sun heats the system back up, that moisture is released. It then condenses on a collection plate the feeds into a container as potable water. It doesn’t provide a lot of water — only about 0.8 liters a day for a one square meter area — but it is something. If the efficiency can be improved, a scaled-up version of the system could provide enough drinking water for a small family.