Solar-powered System can Harvest Fresh Water From Air

It operates at ambient temperature with ambient sunlight, and with no additional energy input, you can collect water in the desert. This laboratory-to-desert journey allowed us to really turn water harvesting from an interesting phenomenon into a science

Using just solar power, the scientists have developed a system that can harvest water out of the air which can be of great help for the people living in dry areas of the world.

Omar Yaghi, who invented the technology underlying the harvester said, “It operates at ambient temperature with ambient sunlight, and with no additional energy input you can collect water in the desert. This laboratory-to-desert journey allowed us to really turn water harvesting from an interesting phenomenon into a science.”

The trial in Scottsdale, where the relative humidity drops from a high of 40 percent at night to as low as 8 percent during the day, demonstrated that the harvester should be easy to scale up by simply adding more of the water absorber, a highly porous material called a metal-organic framework (MOF).

Metal-organic frameworks are solids with so many internal channels and holes that a sugar-cube-size MOF might have an internal surface area the size of six football fields.

This surface area easily absorbs gases or liquids but, just as important, quickly releases them when heated.

The researchers anticipate that with the current MOF (MOF-801), made from the expensive metal zirconium, they will ultimately be able to harvest about 200 milliliters of water per kilogram of MOF.

They have also created a new MOF based on aluminum, called MOF-303, that is at least 150 times cheaper and captures twice as much water in lab tests.

This will enable a new generation of harvesters producing more than 400 milliliters of water per day from a kilogram of MOF.

“There has been tremendous interest in commercializing this, and there are several startups already engaged in developing a commercial water-harvesting device,” Yaghi said.

“The aluminum MOF is making this practical for water production because it is cheap,” he said. For the study published in the journal Science Advances, researchers collected and measured the water and tested the latest generation harvester under varying conditions of humidity, temperature, and solar intensity.

Source: PTI