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The Water Abundance XPrize winner makes water from air

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Re: The Water Abundance XPrize winner makes water from air

#41

Post by corodra »

JackFr wrote: post #29
corodra wrote: post #20

Earlier quoted context omitted.

Just google “water from thin air”. This has been done quite often the past 15 years. It’s an overpriced dehumidifier that is working outdoors. 1. They’re in Hawaii. It’s a little humid there. So... yea. Dehumidifiers will collect quite a bit of water in a water abundant area. 2. The places that need clean water typically have low humidity as well. To pull water from air, there needs to be water in it. Think of this a…

> They’re in Hawaii. So what you're saying is that they're efficient on an island miles from the the rainiest spot on the planet. https://en.wikipedia.org/wiki/Mount_Waialeale#Climate_and_Ra...

You’d figure they would test something like this for efficiency in the desert. Just to be practical.

Re: The Water Abundance XPrize winner makes water from air

#42

Post by moonbug »

stephengillie wrote: post #32
corodra wrote: post #25

It’s an overpriced dehumidifier. Pulling humidity out of the air. It’s not magic. It’s not new. There is water vapor in the air, every middle schooler knows this. They are in Hawaii. An outdoor dehumidifier will work great in a water abundant area. How well do you think a dehumidifier will work in a low humidity area? The places that need water the most. It’s not making water, it’s pulling out the humidity. This is s…

This reminds me of desert water collectors. There are so many that it's hard to find any specific one. Here are a few examples. http://www.cais-soas.com/CAIS/Architecture/wind.htm https://www.ancient-origins.net/ancient-technology/sophistic... https://www.smithsonianmag.com/innovation/this-tower-pulls-d... https://en.m.wikipedia.org/wiki/Air_well_(condenser) http://starwars.wikia.com/wiki/Moisture_vaporator http://ww…

You do know Star Wars isn't real?

Re: The Water Abundance XPrize winner makes water from air

#43

Post by sdenton4 »

jryan49 wrote: post #33
corodra wrote: post #25

It’s an overpriced dehumidifier. Pulling humidity out of the air. It’s not magic. It’s not new. There is water vapor in the air, every middle schooler knows this. They are in Hawaii. An outdoor dehumidifier will work great in a water abundant area. How well do you think a dehumidifier will work in a low humidity area? The places that need water the most. It’s not making water, it’s pulling out the humidity. This is s…

I think the key difference is that "Skywater machines use a patented Adiabatic Distillation Process, where water vapor is reduced to liquid without a gain or loss of heat." so it's a little different than just a regular dehumidifier. It also seems to be able to pull a lot more water than a normal dehumifiier? "Skywater machines are ranging from Skywater 30 (up to 30 gallons of water each day) to Skywater 300 (up to 3…

The prize requirements limits costs to two cents a gallon, it looked like, so can't be all that bad in the energy front.

Re: The Water Abundance XPrize winner makes water from air

#44

Post by 08-15 »

azernik wrote: post #12
post_break wrote: post #9

Earlier quoted context omitted.

For instance: https://www.youtube.com/watch?v=vc7WqVMCABg

That's a pretty apples-and-oranges comparison. That's a company making ridiculous promises (look ma, no external power input!) and without any third-party verification. This is a company that makes realistic claims (i.e. has actual numbers for power input per liter of water) and whose performance has been verified by the prize-awarding organization.

> has actual numbers for power input per liter of water

Where did you find that? All I could find is "0.8-1.8kW/hr" for a machine with capacity with a capacity of "30gal/day". This is complete nonsense, "kW/hr" is neither energy nor power nor energy per volume of product. And if it's power, why does it vary?

I'm going to read it as 1.8kW, with a capacity of 30 US gallons (113l) per day. My dehumidifier from the hardware store consumes 0.2kW at a capacity of 10l per day. They are 15% more productive... hardly a quantum leap.

Re: The Water Abundance XPrize winner makes water from air

#45

Post by jonshariat »

corodra wrote: post #25

It’s an overpriced dehumidifier. Pulling humidity out of the air. It’s not magic. It’s not new. There is water vapor in the air, every middle schooler knows this. They are in Hawaii. An outdoor dehumidifier will work great in a water abundant area. How well do you think a dehumidifier will work in a low humidity area? The places that need water the most. It’s not making water, it’s pulling out the humidity. This is s…

Its much more than that. Here are the requirements they met (listen in the second paragraph)

"easily deployable high-volume water generator that can be used in any climate, meeting the competition parameters of extracting a minimum of 2,000 liters of water per day from the atmosphere using 100 percent renewable energy, at a cost of no more than two cents per liter."

Re: The Water Abundance XPrize winner makes water from air

#46

Post by 08-15 »

"Skywater is an ideal solution for [...] Cooling Tower water recovery"

Hilarious. If it was possible to recondense the evaporated water and somehow reject the heat to the air, there wouldn't be a cooling tower!

Thunderfoot is right, it's a scam: https://www.youtube.com/watch?v=e3s-xI895zc

Re: The Water Abundance XPrize winner makes water from air

#47

Post by petermcneeley »

I actually had a discussion on this subject with Phil Mason aka Thunderfoot who has a Phd in chemistry and is the creator of the video that is critical of this announcement ( https://www.youtube.com/watch?v=e3s-xI895zc )

The discussion was about how much work is actually required to condense the water vapor. The fact is that it is thermodynamically possible to MOVE more heat energy (Q) than work (W) applied. The efficiency of heat movement is dependent on temperature gradient but is more than 100% efficient. So as bizarre as this sounds it actually requires effectively zero work to condense water from the air at 100% humidity.

Re: The Water Abundance XPrize winner makes water from air

#48

Post by joshe »

I don't know why this is attracting so much bitterness.

If anyone is informed about water, it would be great to get a little more context, for example what other solutions like desalinization and other dehumidifiers cost in energy and dollars. (Yes, obviously nothing is going to be as cheap as putting a pipe in a river.)

For example their FAQ says they use less than half the power of their competitors. That seems like a huge advance. And is $.02/liter amazing or just slightly better?

Re: The Water Abundance XPrize winner makes water from air

#49

Post by aliswe »

corodra wrote: post #20
CompelTechnic wrote: post #2

Does anyone have any details about their actual technical implementation? I'm sure it is interesting. I imagine it doesn't look too similar to a Tatooine moisture farm.

Just google “water from thin air”. This has been done quite often the past 15 years. It’s an overpriced dehumidifier that is working outdoors. 1. They’re in Hawaii. It’s a little humid there. So... yea. Dehumidifiers will collect quite a bit of water in a water abundant area. 2. The places that need clean water typically have low humidity as well. To pull water from air, there needs to be water in it. Think of this a…

https://m.gulfnews.com/news/uae/weather/humidity-in-uae-reac...

Re: The Water Abundance XPrize winner makes water from air

#50

Post by petermcneeley »

petermcneeley wrote: post #47

I actually had a discussion on this subject with Phil Mason aka Thunderfoot who has a Phd in chemistry and is the creator of the video that is critical of this announcement ( https://www.youtube.com/watch?v=e3s-xI895zc ) The discussion was about how much work is actually required to condense the water vapor. The fact is that it is thermodynamically possible to MOVE more heat energy (Q) than work (W) applied. The effi…

* Not to clutter hn but here are my notes for that discussion:

http://www.sfu.ca/~mbahrami/ENSC%20461/Notes/Refrigeration%2... http://hyperphysics.phy-astr.gsu.edu/hbase/Kinetic/watvap.ht... this shows that its quite large amount Efficiency fridge = 1 / ( Th / Tl - 1)

There is actually way more water in the air than 0.04 grams... i think this is because liters not m^3 for 1m^3 there is 30 grams at 30 degrees and 17.3 at 20 degrees. its at least ~15/10 - > 1.5 grams per Centigrade Say we do small diff of 4 degrees, 30 to 26. We gain 1.5 * 4 = 6 grams / m^3 To do this we need to cool 1m^3 water at 30 to 20. Now this is tricky because humidity but https://www.engineeringtoolbox.com/heating-humid-air-d_693.h... h = 1.01 (kJ/kg.oC) t + x [1.84 (kJ/kg.oC) t + 2502 (kJ/kg)] x is relative weight so its actually small like 0.03 so it changes the result very little h = 1.06 (kJ/kg.oC) t + x 2502 Kj/kg partial diff with t gives us 4.24kJ/kg change for cooling the air (sensible) partial diff with x gives us (0.006kg delta) 2500 - > 15kJ/kg for this 4 degree change for condensation with 6g/m^3 of water Since the cooling of air that didnt result in water is reclaimable energy lets ignore it Now efficiency of this heat transfer 1/ (303.15 / 299.15 - 1) = 75x heat transfer efficiency. Does this make sense? we know heat pumps are amazing :) so per gram its like 15kJ/6g = 2.5kJ/gram -> this is really expected as 2.3MJ/kg from original video!

However this heat (Q) is moved via work (W) at 75x rate This means to get 1kg (1L really) it only takes 30KJ So at 15watts (J/sec) -> 2000sec -> 33 min Perhaps this wont work because the MASSSIVE heat sink required :)

How much air needs to be moved? we get 6 grams for each meter cubed of air. Not great thats about 166m^3 of air that needs to filter. https://www.amazon.ca/Ultra-Strong-DC12V-Cooling-200CFM/dp/B... 200CFM -> 5.66 m^3/min 60 min/h = 339 ... this is double what we need. its about 1.6A 12v = 15 watt... but its more than we need. Half it?

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