Extracting drinking water from dry desert air is no longer a pipe dream

Imagine you’re stuck in the Australian desert. Your car has broken down, and there’s no sign of another person for miles.

A survival expert will tell you your first priority is finding water.

It’s probably not a situation many of us will ever face, but for some people and in certain regions of the world, reliable access to clean drinking water can be a constant struggle, and droughts can be deadly.

more…

pardon me….wrong thread.

From Dune.

She glanced back as they passed beyond the arch, said: “They hurry to finish the quota in the plastics shop before we flee. We need many dew collectors for the planting.”

“Flee?”

“Until the butchers stop hunting us or are driven from our land…”

“What’re dew collectors?” he asked.

The glance she turned on him was full of surprise. “Don’t they teach you anything in the . . . wherever it is you come from?”

“Not about dew collectors.”

“Hai!” she said, and there was a whole conversation in the one word.

“Well, what are they?”

“Each bush, each weed you see out there in the erg,” she said, “how do you suppose it lives when we leave it? Each is planted most tenderly in its own little pit. The pits are filled with smooth ovals of chromoplastic. Light turns them white. You can see them glistening in the dawn if you look down from a high place. White reflects. But when Old Father Sun departs, the chromoplastic reverts to transparency in the dark. It cools with extreme rapidity. The surface condenses moisture out of the air. That moisture trickles down to keep our plants alive.”

“Dew collectors,” he muttered, enchanted by the simple beauty of such a scheme.

From article.

The key to the water-capturing capacity of the design is the massive surface-area-to-mass ratio of the meta-organic framework (MOF) powder. The device is opened at night when desert air is at its most saturated, allowing water to be absorbed by the MOF powder. During the day, the insulated case is closed and an aerogel is placed over the top of the MOF powder, which absorbs heat from the sun. When water vapour released from the heated powder comes in contact with a condenser which has been cooled overnight, it cools and condenses the vapour, allowing the liquid to be collected.

The zirconium-based MOF-801 design, which they field tested in the Arizona desert, was able to yield around 100 millilitres of water per kilogram of powder. Lab testing has shown the newer MOF-303 to be far more efficient.

So it works like the dew collector from Dune, but has a much greater surface area which makes things better, and the absorption of water is chemical rather than physical, which again is better. At the expense of greater complexity and cost.

The second part is about a new X-prize. The XPRIZE competition challenged entrants to “create a device that extracts a minimum of 2,000 litres of water per day from the atmosphere using 100 per cent renewable energy, at a cost of no more than 2 cents per litre”. Want to have a go?

Similar to the Berkeley model, Professor Moghtaderi’s system absorbs water at night into silica pouches. The pouches are then heated by solar energy during the day releasing water vapour, which is then cooled. But unlike the Berkeley design, Professor Moghtaderi’s unit uses solar energy to heat the air in the system, and to drive a fan and condenser.

mollwollfumble said:

The second part is about a new X-prize. The XPRIZE competition challenged entrants to “create a device that extracts a minimum of 2,000 litres of water per day from the atmosphere using 100 per cent renewable energy, at a cost of no more than 2 cents per litre”. Want to have a go?

It is called a tree.

mollwollfumble said:

The second part is about a new X-prize. The XPRIZE competition challenged entrants to “create a device that extracts a minimum of 2,000 litres of water per day from the atmosphere using 100 per cent renewable energy, at a cost of no more than 2 cents per litre”. Want to have a go?

That’s like 10 steel drums a day. That is a lot of water.