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From seawater to drinking water, with the push of a button

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Re: From seawater to drinking water, with the push of a button

#11

Post by fiddlerwoaroof »

MichaelApproved wrote: post #9
siruva07 wrote: post #4

Earlier quoted context omitted.

Maybe. I think Atmospheric Water Generators are much More likely to change the game since they don’t need a body of water other than the atmosphere.

“ Atmospheric Water Generators ” At first I thought you were just using a marketing term for dehumidifiers but I looked it up before posting. I see that term is used for tight mesh fabric that’s hung vertically as a passive matrix to collect condensation. While those are actually game changers, they unfortunately only work in special regions that have the needed weather and topography to make them work. I think there…

I wonder if you could use a similar sort of device with weather balloons to harvest water from clouds.

Re: From seawater to drinking water, with the push of a button

#12

Post by MichaelApproved »

tomxor wrote: post #10
MichaelApproved wrote: post #6

Edit: I wrote out the comment below criticizing the efficiency of this device, when compared to reverse osmosis RO desalination (100x less efficient). However, they’re not trying to be more efficient than RO devices, they’re trying to be more compact, portable, and avoid the need for filters. They’re solving for a different problem than I was measuring them against. In my race to criticize, I overlooked those key det…

From the article it sounds like they are looking for ways to scale down (i.e small portable units are the target form factor, not a mere demo), and this is where it compares favourably against things like reverse osmosis for efficiency.

I was so quick to criticize technology that I completely overlooked those points. Reading the article again, it’s embarrassing to see that I missed it when they were emphasizing it so much.

I have one more lingering criticism that I don’t think they addressed (I reread it twice).

What happens to the salt after it’s removed? If they don’t have a filter, where does it go? Do they pump brine water back?

Re: From seawater to drinking water, with the push of a button

#13

Post by electroly »

MichaelApproved wrote: post #6

Edit: I wrote out the comment below criticizing the efficiency of this device, when compared to reverse osmosis RO desalination (100x less efficient). However, they’re not trying to be more efficient than RO devices, they’re trying to be more compact, portable, and avoid the need for filters. They’re solving for a different problem than I was measuring them against. In my race to criticize, I overlooked those key det…

FWIW, I think you made a minor math error; you lost track of the 30 minutes. It would be 1 ounce of water for 3 watts of power over 30 minutes, which is 1.5 Wh of energy. That's 666 ounces per kWh.

Re: From seawater to drinking water, with the push of a button

#14

Post by photochemsyn »

If this unit is shown to be durable, I imagine it's the kind of thing a lifeboat would have as part of its equipment. Low power means low volume of drinkable water (as energy is needed to separate ions from seawater, by the laws of entropy), so that's really unavoidable with this system.

Compare to things like concentrated solar for complete removal of solids from wastewater and seawater, here's an interesting example (relies on condensation of steam):

https://influencing.com/pr/99083/novel-solar-powered-water-t...

Re: From seawater to drinking water, with the push of a button

#15

Post by QuikAccount »

MichaelApproved wrote: post #12
tomxor wrote: post #10

Earlier quoted context omitted.

From the article it sounds like they are looking for ways to scale down (i.e small portable units are the target form factor, not a mere demo), and this is where it compares favourably against things like reverse osmosis for efficiency.

I was so quick to criticize technology that I completely overlooked those points. Reading the article again, it’s embarrassing to see that I missed it when they were emphasizing it so much. I have one more lingering criticism that I don’t think they addressed (I reread it twice). What happens to the salt after it’s removed? If they don’t have a filter, where does it go? Do they pump brine water back?

You can pump brine water back but if I recall you can't just dump it all back at once because it's so highly concentrated. Ideally you would be able to find an alternate use for it.

Re: From seawater to drinking water, with the push of a button

#16

Post by kortex »

fiddlerwoaroof wrote: post #11
MichaelApproved wrote: post #9

Earlier quoted context omitted.

“ Atmospheric Water Generators ” At first I thought you were just using a marketing term for dehumidifiers but I looked it up before posting. I see that term is used for tight mesh fabric that’s hung vertically as a passive matrix to collect condensation. While those are actually game changers, they unfortunately only work in special regions that have the needed weather and topography to make them work. I think there…

I wonder if you could use a similar sort of device with weather balloons to harvest water from clouds.

I could totally see a Project Loon style craft which automatically surfs the crosswinds, going up above the clouds to radiate heat to the open sky at night, and descending to condense water.

Re: From seawater to drinking water, with the push of a button

#17

Post by FR10 »

MichaelApproved wrote: post #9
siruva07 wrote: post #4

Earlier quoted context omitted.

Maybe. I think Atmospheric Water Generators are much More likely to change the game since they don’t need a body of water other than the atmosphere.

“ Atmospheric Water Generators ” At first I thought you were just using a marketing term for dehumidifiers but I looked it up before posting. I see that term is used for tight mesh fabric that’s hung vertically as a passive matrix to collect condensation. While those are actually game changers, they unfortunately only work in special regions that have the needed weather and topography to make them work. I think there…

> It’s providing water in the Atacama Desert near Lima Peru.

I think one big issue is that in winter (May-September) not every day is foggy, so sure its helpful but not a perfect solution. It does get really foggy though in June-October. Thus we get natural vegetation in otherwise arid hills around Lima, the most popular called Lomas de Lachay[0].

[0] https://en.wikipedia.org/wiki/Lachay_National_Reserve

Re: From seawater to drinking water, with the push of a button

#18

Post by MichaelApproved »

electroly wrote: post #13
MichaelApproved wrote: post #6

Edit: I wrote out the comment below criticizing the efficiency of this device, when compared to reverse osmosis RO desalination (100x less efficient). However, they’re not trying to be more efficient than RO devices, they’re trying to be more compact, portable, and avoid the need for filters. They’re solving for a different problem than I was measuring them against. In my race to criticize, I overlooked those key det…

FWIW, I think you made a minor math error; you lost track of the 30 minutes. It would be 1 ounce of water for 3 watts of power over 30 minutes , which is 1.5 Wh of energy. That's 666 ounces per kWh.

It wouldn’t be the first time I made a mistake like that by not clearly identifying my units but I think I got it right.

Let me rephrase and use watt/hour units.

I was assuming it was a 50 watt panel that would only produce 30wh from the weak winter sunlight.

Divide 30wh by two (since it was only ru Ning for half an hour) and get 15 watts generated to purify 5 ounces.

Had they let it run for the full hour, they’d get 10 ounces from my assumed 30wh of energy the panel produced.

30wh divided by 10 ounces would be 3wh per ounce (or unit of water produced).

How many units of water can be produced by 1kwh? Let’s divide 1,000wh by 3wh to get the result of 333.3 units (ounces) produced.

Re: From seawater to drinking water, with the push of a button

#19

Post by MichaelApproved »

QuikAccount wrote: post #15
MichaelApproved wrote: post #12

Earlier quoted context omitted.

I was so quick to criticize technology that I completely overlooked those points. Reading the article again, it’s embarrassing to see that I missed it when they were emphasizing it so much. I have one more lingering criticism that I don’t think they addressed (I reread it twice). What happens to the salt after it’s removed? If they don’t have a filter, where does it go? Do they pump brine water back?

You can pump brine water back but if I recall you can't just dump it all back at once because it's so highly concentrated. Ideally you would be able to find an alternate use for it.

For these small amounts, I doubt pumping it back out would be an issue but is that what they’re doing?

I thought the metal plates were collecting the salt but the article and video don’t make it clear.

Re: From seawater to drinking water, with the push of a button

#20

Post by MichaelApproved »

nkingsy wrote: post #7

From the article: The limitations appear to be expensive materials and scale. 20w per liter .3 liters per hour

The article claims 3x more efficiency in a confusing sentence:

”Their prototype generates drinking water at a rate of 0.3 liters per hour, and requires only 20 watts of power per liter.”

So the unit only produces 0.3 liters an hour but if you wait 3 hours and provide 20 watts of power (7watts/hour), you’ll have a full liter.

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