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Harvest Fresh Water from Air with Solar-Powered System

KJ Staff
KJ Staff

Now this saying is wrong that water cannot be harvested, only we conserve the water. The world scientist was working on the phenomena of harvesting the water. The researchers at California University, Berkeley in the United States at low cost and at low humidity are able to extract drinkable water every day/night cycle. It is also interesting to note that in view of renewable energy, to harvest water from the air the scientists had used solar power. There are five elements i.e. Earth, Sky, Sun, Air, Water. The scientists were able to get the water from the air through the Sun on this earth under the sky.

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.

Omar Yaghi, who invented the technology underlying the harvester explained 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 millilitres of water per kilogramme 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 millilitres of water per day from a kilogramme 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.

The harvester is essentially a box within a box. The inner box holds a two-square-foot bed of MOF grains open to the air to absorb moisture. This is encased in a two-foot plastic cube with transparent top and sides. The top was left open at night to let air flow in and contact the MOF, but was replaced during the day so the box could heat up like a greenhouse to drive water back out of the MOF.

The released water condensed on the inside of the outer box and fell to the bottom, where the researchers collected it with a pipette. The extensive field tests lay out a blueprint allowing engineers to configure the harvester for the differing conditions in Arizona, the Mediterranean or anywhere else, given a specific MOF.

"The key development here is that it operates at low humidity, because that is what it is in arid regions of the world," Yaghi said. In these conditions, the harvester collects water even at sub-zero dew points.

Around the world, approximately 2.1 billion people do not have immediate access to clean drinking water. In a Business Insider, the sustainable water startup called Zero Mass aims to make clean water easily accessible to more people around the world. In 2015, it launched its first product, Source - a solar panel array that harvests and filters water from vapor in the air - in eight countries, including Chile, Jordan, and Peru.

Source is now available in the United States, CEO Cody Friesen, a material scientist and MIT alum.

Each panel costs $2,000 (plus a $500 installation fee) and generates an average of two to five liters of water daily, depending on humidity and sunlight. Source can work anywhere, and many arrays are deployed in deserts where water is scarce, Friesen said.

Comprised of proprietary materials, the panels use sunlight to produce heat, which allows them to collect water vapor from the air. Friesen wouldn't disclose what the materials are, but said they have an ideal binding energy for humidity.

The harvested vapor is sterilized and turned into a liquid. The device adds minerals to increase the water's pH levels (to make it taste more like bottled water), and it's stored underneath the panels in a reservoir that can hold 30 liters. Lastly, the water travels from the reservoir through a pipe to a faucet.

The arrays are customized based on the customer's needs, Friesen said. A typical Source for a home has two panels, while a school in Mexico City with 50 students has 10 panels. If a two-panel array harvested five liters of water daily, it would be enough for a family of three (if everyone followed the Us Departmant of Health and Human Services consumption recommendation).

To make sure everything is working properly, Zero Mass tracks the Sources' outputs using sensors installed in the arrays. The team is studying data points, like pH levels, temperature, and humidity, to maximize the amount of water each array produces and to improve future iterations of Source.

When asked about who Zero Mass' ideal customer is, Friesen said "everyone." The company has installed Sources everywhere from multimillion-dollar mansions in California to an orphanage in Lebanon. Duke Energy has also deployed panels in Ecuador, and Zero Mass received a USAID grant to install panels in refugee camps in Jordan and Lebanon in 2015. In an Arizona desert, the company recently put a system that pumps water at night for wild animals.

When you compare Source's price to the cost of buying bottled water, the former is more affordable and sustainable over time. On the other hand, boiling poor-quality water to sterilize it is almost free. For those in low-income areas, Sources are pricey and would likely need to be bankrolled by humanitarian nonprofits.

Friesen added that maintaining the device is low-cost. Air filters need to be replaced every year, and mineral blocks need to be replaced every five years. (Both cost just a few dollars.)

"We want to perfect water for every person and every place," Friesen said. "Although I feel sheepish saying something that bold, I feel confident since the technology is [deployed] across a huge range of places and the fact that it's the best water you can get, it's independent of infrastructure, it's CO2-offsetting, and it pays back really quickly. The ultimate goal is for people to have a fundamental change in their relationship to water and have total independence around it anywhere on the planet."

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