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At scale, this seems awful for desert ecology. Plants and animals have evolved to survive on bare minimum water. The tiny morning dew may be all they get for da
by conductr 4y ago
At scale, this seems awful for desert ecology. Plants and animals have evolved to survive on bare minimum water. The tiny morning dew may be all they get for days/weeks. Now we want to pluck it out before they can get any.
It’s certainly an interesting technology and achievement but one that could be easily misused with “unintended consequences”; or so it seems.
- klvino 4y agoThat was my first thought as well, heavy use within an existing desert environment would likely have negative ecological impact. When reading through the article, it has potential application in areas where a local water supply may not be clean enough to drink or lacks sufficient water treatment & filtration.
- buu700 4y agoOn the flip side, could it potentially be a cost-efficient method of dehumidifying cities/towns/villages for human comfort?
- conductr 4y agoCould even replace desalination since humidity has no salt and it is generally occurring in a similar area/climate.
- bushbaba 4y agoAnd dryer air can absorb more water from the nearby sea...so there might not be a huge impact if placed in the right spot
- sandworm101 4y agoHumidity theoretically doesn't contain salt, but air does. Any technology that is harvesting moisture from air will involve large amounts of air. That air contains dust and sea salt which can contaminate the process. Setup a moisture farm to harvest sea breezes and you will have to address a salt problem. In many industries this airborne salt can cause corrosion. Talk to anyone with a classic car in LA/SF, both cities with sea breezes. They don't want to leave them outside too much. That's why the aircraft "boneyards" are all in the interior, across the mountains from the sea.
- Robotbeat 4y agoWould it? The water will eventually evaporate again. It’s not like the water is burned up to nothing in a fusion reactor.
- flockonus 4y agoCould be easily drained down a pipe, the evaporation then is not as relevant even if some of it does, efficiency would most likely be acceptable.
- blacksqr 4y agoThe amount of water vapor in the air is functionally infinite with respect to any practical means to extract it.
- rtkwe 4y agoOnly true on the large scale but locally you'll still create a depleted zone near the ground down wind of a hypothetical extraction plant.
- colechristensen 4y agoIt could also do the opposite, if used correctly. Strong Dune vibes. You could use these to water plants and set up a cycle where a significant portion of the water lost through evaporation was reclaimed and gradually accumulated locally. Dot a landscape with solar powered stacks of these things feeding appropriately selected plantations and you might make the desert bloom or help prevent the spread of deserts.
- conductr 4y agoThat's an interesting concept I had not considered. I also am not sure if "we" (collective) would roll it out that way. We have a track record of consuming resources in the easiest/cheapest way with minor consideration of the environment. I don't think we'd even view this as a worthy investment if all it did was help prevent the spread of deserts. We still can't even agree if climate change is real and what we should do about it.
- colechristensen 4y agoTo rekindle your hope, see https://en.m.wikipedia.org/wiki/Great_Green_Wall_(Africa) https://en.m.wikipedia.org/wiki/Great_Green_Wall_(Africa)
- conductr 4y agoThat's interesting. Reminds me of when I was a kid and thought I had a completely unique idea to fill the Sahara with water! It will quickly evaporate and turn to a rainforest in no time!! https://en.wikipedia.org/wiki/Sahara_Sea https://en.wikipedia.org/wiki/Sahara_Sea
- dylan604 4y agoI have little trust in the "we" doing anything like this correctly, at first. By that, I mean that it will be the corps to do this as they are the ones with the money to do it. Corps being corps, they will lean into being themselves and extract all of the everything they can with little respect for anything other than their bottom line. I don't have faith gov't will do it either. Those opposed to climate change will argue it is money spent on fake science. It'll die in congress (for US, s/congress/localGovUselessBody/ for other places). Someone might get popular enough to crowd source fund it with an NGO type thing, but I'm not holding my breath there either.
- ttul 4y agoAt 20C, the maximum water content in air is 17.3 x 10^-3 kg/m^3. At 15% relative humidity, then, you can extract a maximum of 0.15 x 17.3g = 2.6g from every 1,000L of air. If a person needs 5L/day for survival (I am making this up), then you’d need to dry out 5000 / 2.6 = 1,923L of air each day — that’s just short of two cubic meters… If the density of people living in an area is 50 per square km, drying the air out to extract water would deplete the first meter of the atmosphere by 10%.
- conductr 4y agoIf those people are living there 5L/day is nowhere near enough water. They are doing more than just surviving. Using Arizona as an example, Google tells me 550L/day/person is actual usage. I know you just put an assumption in but this is a big gap.
- function_seven 4y ago1,923,000L per day, right? So each person would need just short of 2,000 m³ of air.
- TwistedWave 4y ago1,923m^3, not 1,923L
- bufferoverflow 4y ago> If a person needs 5L/day for survival (I am making this up), then you’d need to dry out 5000 / 2.6 = 1,923L of air each day You made a unit conversion mistake there. It's 1923 cubic meters, not liters.
- throwaway894345 4y agoDeserts are expanding; it seems fine to offset that expanse as long as you're somewhat careful not to wipe out an entire ecosystem.
- dawsmik 4y agohttps://wxguys.ssec.wisc.edu/2018/02/05/water-in-atmosphere/#:~:text=At%20any%20one%20instant%2C%20the,inch%20of%20rain%20if%20condensed https://wxguys.ssec.wisc.edu/2018/02/05/water-in-atmosphere/....
- grishka 4y agoBut the water someone plucked out of desert air and drank doesn't poof out of existence. They'll eventually pee and sweat it out.
- a1369209993 4y ago> They'll eventually pee and sweat [the water] out. It's infuriatingly hard to find good citations, but I think they actually mostly breathe it out. IIRC, the water breakdown for some (spacecraft) life support system was something like 50% from respiration, 30% in urine, 10% in sweat, and 10% in feces.
- jhgb 4y ago> Now we want to pluck it out before they can get any. I suspect that if you think that this is going to give us the ability to suck out all the water out of thousands of cubic kilometers of desert air any time soon, you're probably being a little too optimistic.
- rhexs 4y agoThis is entirely dependent on whether or not Nestlé MBAs calculate they can make a profit with this bottling "Desert Air Water".
- nopenopenopeno 4y agoYup. That is precisely how global warming works.
- tomcam 4y agoSort of an interesting point. But don’t forget, in the Sahara, for example, there was less vegetation only 5000 or 6000 years ago
- AnimalMuppet 4y agoLess vegetation 5000 years ago? Are you sure you don't mean more? Wikipedia speaks of an "abrupt desertification" 5400 years ago.
- tomcam 4y agoYes I meant more. Downvotes absolutely justified.
- AnimalMuppet 4y agoYeah, well, I've never mis-spoken in a post on HN. Never. (Furtively checks posting history) Or at least not today....
- tomcam 4y agoI’m always grateful for the corrections, but thank you for doing it so gracefully.