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Google open sources solar atmospheric water generator

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Re: Google open sources solar atmospheric water generator

#221

Post by kragen »

ptrklly wrote: post #140
jodrellblank wrote: post #107

Check out Thunderf00t's videos cricising solar water collectors, e.g.: - https://www.youtube.com/watch?v=vc7WqVMCABg - Zero Mass Water: BUSTED! "Honestly, it drives me crazy how many people have reinvented the dehumidifier, put a solar panel on it, and the media has danced around like theyve just saved the world!" - https://www.youtube.com/watch?v=aPvXnmBIO7o - Self-filling water bottle: BUSTED! " The fact that its t…

I don't have views on the credibility of specific technologies but I've hoped that these could be viable in places like coastal California where fog provides quite a bit of air moisture but it never rains--do you not agree with that?

If you have fog or dew, you can just use a fog net: https://en.wikipedia.org/wiki/Fog_collection https://news.climate.columbia.edu/2011/03/07/the-fog-collect...

These are mentioned in Table 1 of the Nature article: https://www.nature.com/articles/s41586-021-03900-w.pdf

In coastal California, redwood trees have been doing this since the Jurassic.

In the conditions you describe, fog nets commonly yield 2–3 ℓ/m²/day of water (20–30 nm/second), though experimental projects have reached yields over 13 ℓ/m²/day (150 nm/s): https://www.oas.org/dsd/publications/unit/oea59e/ch12.htm

Fog nets are easier to make and easier to repair, and consequently enormously cheaper. This makes them practical not only for drinking water but even for irrigation. They are more tolerant of damage, though they do need yearly maintenance. But they don't work on days without dew, and in some places, that's nearly all days.

Re: Google open sources solar atmospheric water generator

#222

Post by kragen »

blkhawk wrote: post #127
kragen wrote: post #124

Earlier quoted context omitted.

Dehumidifiers aren't what's thermodynamically impossible, of course; Fontus was just making quantitative performance claims that were thermodynamically impossible about how small their system would be and how little energy it would use. You don't need to sink to citing YouTubers to figure out how much water air contains. You can just consult a standard psychrometric chart: https://commons.wikimedia.org/wiki/File:Psyc…

You also need power to take the heat away that is created when the water in the air turns into a liquid. Best case you need to cool for about 0.7kwh per litre of water you make. That means for your 10 litre example you need best case 7kwh. That is a decent sized solar array and if you have any inefficiencies in your heat pump setup it gets much worse. Also you assume per day - solar only works during the day so you n…

It's worth noting that the Nature paper abstract https://www.nature.com/articles/s41586-021-03900-w.pdf claims they're spending as little as 0.4kWh/ℓ, which is less than the 0.68kWh/ℓ of the enthalpy of vaporization, though more than the 0.34kWh/ℓ of the enthalpy of vaporization divided by the CoP of a commonplace vapor-compression heat pump. (They point out that "solar-driven cooler–condenser devices suffer from a steep loss in electric energy conversion", by which I think they mean photovoltaic panels are only about 21% efficient, so you lose 79% of your sunlight before it can start driving your compressor.) They're using a sorbent-based cycle rather than a vapor-compression cycle. I should have read this before commenting.

They cite a paper by Kim et al. that calculates the thermodynamic limits on the specific yield of atmospheric water harvesting as 5–50 ℓ/kWh (0.02–0.2 kWh/ℓ), which I suppose depends on the air temperature and humidity.

Re: Google open sources solar atmospheric water generator

#223

Post by jcranberry »

jodrellblank wrote: post #107

Check out Thunderf00t's videos cricising solar water collectors, e.g.: - https://www.youtube.com/watch?v=vc7WqVMCABg - Zero Mass Water: BUSTED! "Honestly, it drives me crazy how many people have reinvented the dehumidifier, put a solar panel on it, and the media has danced around like theyve just saved the world!" - https://www.youtube.com/watch?v=aPvXnmBIO7o - Self-filling water bottle: BUSTED! " The fact that its t…

The linked nature paper points out that over a billion people without access to safe drinking water live in areas where their design would be high performance (tropical areas).

Re: Google open sources solar atmospheric water generator

#224

Post by kragen »

kragen wrote: post #134
Untit1ed wrote: post #131

Earlier quoted context omitted.

Then you probably don't have humidity either, so the collector won't work.

No, that's not true; it's just less efficient because you have to handle more air and cool it to a lower temperature. Air in Earth's atmosphere always has significant humidity. See https://news.ycombinator.com/item?id=30716765 for some calculations. It's reasonable to condense drinking/cooking water from air with solar energy in places that lack secure water. Not water for other purposes; you can't run a cooling towe…

It's worth pointing out that the sorbent-based systems in the H2E project don't work by cooling air below ambient temperature.

Re: Google open sources solar atmospheric water generator

#225

Post by capitalsigma »

antonvs wrote: post #210
TaylorAlexander wrote: post #170

Earlier quoted context omitted.

It's cool, but one gets kind of irritated when they talk this big talk about changing the world but do not seem to appreciate just how transformative open source can be as a tool for innovation. At least, I got frustrated.

> they talk this big talk about changing the world The unspoken part of that is that the changes in question should be profitable for Alphabet. Anything else is just PR for recruiting and marketing.

The X website is very explicit that X is not a non-profit:

> "Is it a research center? An incubator? A non-profit? No, it’s a moonshot factory"

Re: Google open sources solar atmospheric water generator

#227

Post by moffkalast »

whatshisface wrote: post #85
moffkalast wrote: post #80

Earlier quoted context omitted.

Then you just put it into a pot, hook up another pot with a tube, then set a fire under the first one. Basic distillation isn't rocket science.

Energy costs are the major limiter to desalination and the availability of water more broadly. One or two people can do that but if an entire civilization does it they'll clearcut their forests and make the air unbreatheable. Cooking fires are a major source of air pollution in many Indian cities.

I think these systems were always intended for small scale use for detached villages and whatnot? I don't see a way they would be able to provide for city even if you made hundreds of thousands.

If you want to support a civilization you better switch to something that can exploit the volume for increased efficiency, like an actual desalinization plant and a solar concentrator powerplant to run it.

Re: Google open sources solar atmospheric water generator

#228

Post by traverseda »

dwighttk wrote: post #179
jupp0r wrote: post #173

Earlier quoted context omitted.

Why would you care how energy intensive it is when it’s solar powered?

Go buy a 40 pint per day dehumidifier and then start sizing the solar power you will need to run it all day, and then make sure there is enough humidity in the air to actually get 40pints/day and make sure there is enough battery to make up for the days that aren’t sunny, and realize the people who need water generally don’t have that much water in the air, and then realize this is a pipe dream.

It's not solar-electric, it's solar-thermal. Does need some power to circulate the desiccant.

Re: Google open sources solar atmospheric water generator

#229

Post by traverseda »

mrexample wrote: post #226

Thundefoot debunked similar products. I bet this finds no traction in real world. Only Americans buy into this kind shit and Elon Musks stupid ideas

A lot of people bringing up the thunderfoot video without realizing that this is... a completely different device. This is not solar-electric for one, it's direct solar heat. There's no peltier elements or anything like that, it uses ground temperature to provide the cold side of the dehumidifier. It does have a small electric motor and circulating fan, but that does not require very much power at all.

It's a largely passive device and not really comparable to the solar electric designs.

I wish people would use their own brain instead of just parroting whatever thunderfoot says. Maybe the problem is that people aren't finding the actual overview PDF? https://github.com/google/h2e_technical_documentation/blob/m...

Re: Google open sources solar atmospheric water generator

#230

Post by traverseda »

jodrellblank wrote: post #107

Check out Thunderf00t's videos cricising solar water collectors, e.g.: - https://www.youtube.com/watch?v=vc7WqVMCABg - Zero Mass Water: BUSTED! "Honestly, it drives me crazy how many people have reinvented the dehumidifier, put a solar panel on it, and the media has danced around like theyve just saved the world!" - https://www.youtube.com/watch?v=aPvXnmBIO7o - Self-filling water bottle: BUSTED! " The fact that its t…

Very different technology, this is largely not solar-electric. It's solar-thermal with a bit of electric for a circulating fan and a small motor.
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