Atmospheric Water Harvesting | Hacker News Reader

Atmospheric Water Harvesting

chemistryworld.com

47 pointsrch28 comments

They've been trialing this on a remote island on the GBR for a couple of years now. They don't produce a lot of water, in the tens of litres per day I think, but they work (and are fully solar powered). Agree it's a fairly edge use case. https://ladyelliot.com.au/sustainability/water-conservation/

That looks awful compared to compact, simple and readily available desalination units... [1]

On an island, desalination looks much more efficient and reasonable than these contraptions.

[1] https://www.foreverpureplace.com/500-GPD-Seawater-Desalinati...

Absolutely agreed. LEI are using both systems. But still, given the tech works (and current efficiencies aside), surely it shouldn't be written off so early in the game? Also on anecdotal evidence the hydro panel water tastes a bit better than the desal!

Every time I see articles like this I think ‘Great, so where are they going to get access to unlimited free energy?’ That’s about what it would take for ‘Atmospheric water harvesting’ to be economically viable.

Wouldn’t dry, arid, sunny places be the perfect fit for this, then? Solar power and a lack of preexisting water would probably make that scenario economically viable

The amount of energy you need goes up the less moisture there is in the air. The ideal conditions are moist, cool places with cheap electricity. Tropical conditions would have a shot at profitability, but you may as well desal whatever's already there than condense it.

Exactly this. Desalination and transport is aways orders of Magnitude cheaper and more efficient.

I don’t see this changing at any point in the near future. It’s phenomenally energy intensive to pull water out of the air in any quantity.

There are arid places with lots of cheap hydrocarbons, or alternatively, lots of sunlight.

Arid. Meaning no water in the air.

They specifically mention dessicant based tech for arid (which doesn't mean "no" water in the air) locations.

Nuclear fission ?

Desalination?

Desalination indeed is more efficient than what's proposed here. And yes, nuclear power plants often offer desalination facilities.

From the sun

Still not worth it. Just desalinate and transport the ocean. Always more cost and energy efficient.

Oh, another "water from air"-scam, how original. The laws of thermodynamics don't change. There's always a minimum of energy needed to condense water, and it's a lot. That's it, there is nothing more to add. It it possible? Yes. Is it viable at scale? No.

Not sure what you are commenting on here - this article is a review of three different types of technology used to pull water from the air.

I found the discussion far more interesting than this dismissal suggests they would be, in particular:

- improvements in dehumidifier tech,

- development of new dessicants that will potentially be more efficient then dehumidification, and

- new fog-catcher designs (fog catchers are already used as reliable water sources)

There are a number of different companies mentioned, some of which have dubious claims, so maybe one of those is the scam you are referring to?

The article seemed balanced to me, not promoting any one company or technology with outlandish claims. It leads in to the discussion by saying "the majority of these devices operate in the same way as mechanical dehumidifiers", differing in two major ways two major ways:

Firstly, robustness – water harvesters are designed to be operated 24/7, rather than to cycle on and off. Secondly, drinking water quality controls are built into the machines. ‘The coil is coated with a food grade coating so that the water that’s collected isn’t exposed to metal contamination, and the air filter is a much higher quality than in a dehumidifier,’

And then it immediately jumps into why this is generally a Bad Idea

But even though this dehumidifier-like water harvesting technology has been around for a while now, ‘the market is still very small’, explains Ruzhu Wang, a professor of refrigeration engineering at Shanghai Jiao Tong University in China. ‘The reasons are high energy consumption and initial investment costs,’ he adds. Another issue is water capture efficiency; especially in dry, desert conditions where a water harvesting technology might be most needed. The atmosphere must be humid for useful volumes of water vapour to be able to be sucked up using these tools.

This is an area that seems to attract extravagant and unrealistic claims, but I don't think that accusation holds up agains this article.

This reminds me of the "Fontus" Kickstarter:

https://youtu.be/aPvXnmBIO7o

Now we just need a droid that understands the binary language of moisture vaporators, or at least one experienced in programming binary loadlifters.

I believe all the droids were destroyed during the Butlerian Jihad, and the windtraps are managed manually by the Fremen.

Wonder what’s the cost to supply 1 person with drinking and bathing needs.

Zero Mass Water -BUSTED! https://www.youtube.com/watch?v=vc7WqVMCABg

You can do your own research for the other solutions presented in the article.

I find the idea of groundwater recharge interesting.

We dump large amounts of water into the sea having used the Earth as a Atmospheric Water Harvester. We need to be keeping all that.

https://starwars.fandom.com/wiki/Moisture_vaporator

I'll stick to my Fremen Windtraps thank you very much.

So the main thought is how can we get more water from the air. Clouds are inefficient. The problem is in how we can extract usable quantities an leave enough to be normal.

The ocean will replenish what you take out.

Didn't Thunderf00t debunk these already?

People defecating directly into their fresh potable water supply will find no sympathy here when the taps run dry.

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