Tuesday, April 24, 2018

System extracts quarter-liter of water per day per kilogram of MOF from desert air

 This is an extraordinary breakthrough as it operates independent of the dew point.  Thus the constraint will be air flow and that can be handled.  Early days of course but the possibility is clear that we can develop a device able to produce 100 liters per day and then drive the cost down.  Been solar driven we can go into the desert were the need is greatest.

My own approach using either coolant driven systems or inexpensive dew driven systems involved starting outside the edge of the desert where the humidity is high and slowly growing the forest and hardware inward to bring the humidity with you.

All this took serious generational time even though it could easily be made self sustaining.  Hardware like this allows the prospect of actually blanketing the desert with a living forest and seeing rainfall quickly kick in as the forest simply grew.

System extracts quarter-liter of water per day per kilogram of MOF from desert air

brian wang | April 7, 2018

A system, based on relatively new high-surface-area materials called metal-organic frameworks (MOFs), can extract potable water from even the driest of desert air, the researchers say, with relative humidities as low as 10 percent. Current methods for extracting water from air require much higher levels – 100 percent humidity for fog-harvesting methods, and above 50 percent for dew-harvesting refrigeration-based systems, which also require large amounts of energy for cooling. So the new system could potentially fill an unmet need for water even in the world’s driest regions.

By running a test device on a rooftop at Arizona State University in Tempe, Wang says, the team “was field-testing in a place that’s representative of these arid areas, and showed that we can actually harvest the water, even in subzero dewpoints.”

The test device was powered solely by sunlight, and although it was a small proof-of-concept device, if scaled up its output would be equivalent to more than a quarter-liter of water per day per kilogram of MOF, the researchers say. With an optimal material choice, output can be as high as three times that of the current version, says Kim. Unlike any of the existing methods for extracting water from air at very low humidities, “with this approach, you actually can do it, even under these extreme conditions,” Wang says.

The next step, Wang says, is to work on scaling up the system and boosting its efficiency. “We hope to have a system that’s able to produce liters of water.” These small, initial test systems were only designed to produce a few milliliters, to prove the concept worked in real-world conditions, but she says “we want to see water pouring out!” The idea would be to produce units sufficient to supply water for individual households.

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