Almost certainly nonsense. Similar things have been tried before, and as far as I know none worked. Reasons:
* If you have high humidity, you almost always have plentiful rain and water around.
* If you're in a desert, then there's extremely little for any device to work with.
* It takes absolutely enormous amounts of air to extract meaningful amounts of water even in favorable conditions.
* It takes a huge amount of energy, too.
* Any such scheme isn't reliable in any case, and especially unreliable when things are dry and you really need the water. It works best precisely when you don't need it.
* You don't want to drink water from any kind of dehumidifier. It may have started clean, but won't stay that way.
The scale is smaller but i have seen these machines https://www.waterfromair.co.za/ which do condense ambient humidity, filter and purify it and leave it in drinkable form. They look like water coolers without the giant bottle and function like a kind of dehumidifier with some additional steps.
Probably makes sense in a smaller scale “let’s replace our water coolers because water is scarce but we have enough energy” scenario like South Africa.
You would need to extract 814,891,540 gallons of water to equal 1 inch of rainfall on just the city of San Francisco.
Some basic napkin math says at normal temp and humidity that is roughly 84 cubic miles of air you'd need to reduce to 0% humidity. Assuming the process isn't instant, you couldn't contain that volume of air in a structure humans know how to build. You'd also have to build massive air inlet pipes going 5 miles in each direction just to be able to circulate it into the machinery.
Edit: the comment I replied to was talking about areas with "humidity but not rain." I was just pointing out trying to replace rain is an insurmountable problem. You can do all sorts of things to optimize water usage, but that isn't the point. I picked San Francisco because it is a scale most people on HN can understand, but it is still tiny compared to farmland in the central valley.
> Currently in the bay area its 60-80% humidity. It also hasn't rained for weeks.
This brings back my summer Berlin memories. The temperatures are pushing 40, the air is so thick you feel like in Amazon rainforest. But no rain in sight.
The region between alcatraz and pier 47 might be a bit higher.
Honestly I think it would be nice to have a magic drinking water creator, but wouldn't it be distilled water? (which isn't good for you, depleting minerals)
They do have uses is marketing. Vodka has a moisture harvested vodka "made with fog". It goes for 125 per bottle and is usually sold out as far as I can see.
That's a $100 premium which values the "fog" water at roughly $500 / gallon. So if you have a market willing to pay $500 / gallon extra for water harvested from the air this business might work. Not sure how many of those there are.
This will often be more expensive than having a truck bring the water to you when running a dehumidifier especially when you are looking to get out enough for farming.
> * You don't want to drink water from any kind of dehumidifier. It may have started clean, but won't stay that way.
Why?
I have seen how gross dehumidifiers can be. But they are designed to dehumidify, not to provide drinking water. What is preventing one from purifying the water and keeping it that way?
I don't believe this will work but due to its complexity. And even if it will work, the life expectancy of some parts like solar panels is rather short.
IMO projects like fog catchers [0] look much more promising.
It turns out there are a lot of places with humidity but little rainfall. Most of California being one but also places in the middle east. Believe it or not, there are high humidity deserts. There are several companies doing this not for farming but for drinking water. Like Zero Mass Water:
Put another way, if there is enough humidity to work with then there are plants which have evolved to take in that humidity more efficiently than any apparatus. Imagine trying to design something that could compete with bamboo or certain bushes for extracting humidity from the air and either using it or transferring it to the surrounding microclimate.
There are numerous companies that make atmospheric water generators safe to drink that are in some cases solar powered and some that require higher input power. There are some units on Amazon that can do 8 gallons per day [1] and you can drink the water. That might be sufficient for a really small greenhouse using drip irrigation. You could store excess water in tanks. There are much bigger units but the cost goes up exponentially. These folks [2][3] make some bigger units. Here is a station that does 400,000 liters per day [4] Here is a more detailed video that describes the process. [5] There are also some hobbyists on youtube that are making DIY solar powered atmospheric water generators. I think there may come a time that we will need all available options. AWG's, Desalination Plants, Rain Capture at very least. Here is a 20k liter/day unit. [6]
No, no large-scale pooping in rivers. Far more complicated than a single technological fix can handle.
Areas which get 2000+ mm of rainfall a year aren't always the ones with the most intensive agriculture. Water shortages are partly because of (a) the huge variation in the amount of rainfall from year-to-year in any area in India, and this variation has grown with climate change/warming (b) rivers down in the south of the country are not perennial but largely rain-fed during the monsoon. So "build more dams/infrastructure" doesn't make sense if there's not much rain to feed the rivers, (c) certain crops grown (sugarcane,paddy) just require tons of water, and are more likely to face issues due to variable rainfall compared to something like millet cultivation (d) rain is required not just for flow into rivers but for recharging groundwater, which is then used for agriculture. So, no rain = no groundwater and not just no rain = less flow in rivers.
Which highlights another problem with systems like these: Humans generally settle near sources of water already. The problems with water in poor countries is generally not one of water availability, but of water treatment.
I'm not an expert by any means, but your comment reminds me of various nature documentaries in which desert species in certain locales would collect dew in the morning before it evaporates. Conceivably at least in such places it suggests that there is ample moisture in the air, and indeed if nature can get it out of the air then likely we could too. Conceivably an array of metal funnels leading to a bottle or tank (underground or otherwise protected from evaporation) could naturally harvest the moisture in such areas, even without a special hydrogel.
> huge amounts of energy
Condensation doesn't require energy. The energy mentioned in the article seems to be releasing the water from the hydrogel, but in my off-the-top-of-the-head metal funnel example a sufficiently steep big metal funnel can collect the water without any mechanical energy at all.
> Any such scheme isn't reliable in any case, and especially unreliable when things are dry and you really need the water. It works best precisely when you don't need it.
Water is stored easily enough, as long as you keep a surplus on hand for dry spells I don't see the problem?
EDIT: I am curious why my post is being downvoted. This doesn't seem particularly controversial.
Condensation requires energy input, or a considerable change in temperature.
Hot air can hold a lot of moisture, cold air can hold less. Water condenses on surfaces when the air cools down to the point that air would have to carry more water than it can at the new temperature.
Problem with that: it only works great in very humid areas. If you're in a desert, and have 10% humidity, you have to cool down your air by a lot for it to become too saturated and condensation to happen. Not enough cooling, and the moisture stays in the air.
> If you're in a desert, and have 10% humidity, you have to cool down your air by a lot for it to become too saturated and condensation to happen.
Deserts tend to have pretty wild temperature swings. They usually cool down at night. So much so that in most cases you can make ice. You can use the sky as a heat sink (effectively radiating heat into space).
Thanks for the detailed information; that was genuinely informative, but I'm starting from the assumption that the required temperature swings must be present in at least some desert ecosystems as evidenced by the aforementioned documentaries. As the sibling noted, many deserts cool down quite a lot in the evenings.
Well, Space Pirate might be an unrealistic career option. So I have to settle for Moisture Farmer. Maybe some hermit from the hills will come and train in some form of elegant combat from a less barbaric period.
Years ago someone pointed out that the whole alien invasion thing doesn't make that much sense because you're deep in a gravity well at that point, and there are plenty of resources in the Oort cloud and the outer asteroids.
More likely for a sentient species to watch helplessly as an advanced civilization strip mines their outer system of resources long before they can get to them, and not only not be able to even throw rocks high enough to hit them, but perhaps find themselves stranded there not even able to take proper revenge.
There have been quite a few startups based on the same idea (Waterseer etc.) and I think the common consensus is that these devices (which are basically dehumidifiers) are not viable. Thunderf00t has some youtube videos about the Waterseer in which he breaks down the physics behind it.
A nice science project and possibly of use in desert climates or in tiny, extremely densely populated, nations like Singapore. But I don't see how it would be viable or why it would be needed for the vast majority of the world's agriculture. Rain is free.
"two of the world’s biggest problems – water scarcity and food shortage"... neither of these are big problems, or even problems, for the "world". Water scarcity is a problem in a few areas. The world produces multiple times more food than humans could possibly eat (most is fed to animals). Any famine is a local/social/logistical/political problem.
I dunno, if you talk to any farmer's out in the western US water is a big deal, it's what determines where cities/settlements were built, it causes political strain (Colorado vs Kansas on water rights - Colorado has opted to pay fines rather than send water to Kansas) and is in many ways unsustainable (California imports a lot and grows crops that are not drought friendly like Pistachios, forcing droughts to be a different beast than 50 years ago). In a lot of ways water scarcity is one of the most underlying political forces for the western US, though few would know it unless they looked deeper.
I also think it would hold some promise as we de-desertification parts of the world (they are making some progress in the Sahara and also the Badain Jaran in Mongolia/China). Which is important as deserts can creep up and take over places, it's especially concerning as we lose tons of topsoil as we did in the midwest during the dustbowl, and without proper soil management could turn prime farmland into deserts.
Having more water options for dry areas can only be a good thing.
The amount of electricity it would take would be insane and then you're pulling rain out of the atmosphere, impacting your neighbors and region overall.
More water is great, but these things + "urban farming" is just a sales pitch.
super fancy ones with lots of filters basically -- look up "atmospheric water generator" on amazon to see the types that are on the market for home use
Without any cost information we can't really tell anything about the viability of this technology. For example, water in CA ranges from $90 per acre foot from the State Water Project to $3000 for reverse osmosis of seawater.
The only reason I've seen for vertical farming that makes any sense right now is that you can control the environment without damaging the ecosystem around you. Filtered air so no cross pollination with wild strains, no insects, recycled water so no runoff or wasted fertilization, perfectly regulated soil/hydroponics, no PH issues from rain, no herbicides, etc... Good for high value, difficult to raise crops. Usually stuff that costs an arm and a leg like pink lettuce, white asparagus, hop shoots and wasabi root.
Otherwise the entire thing is too expensive. Usually water is more expensive in urban areas and power costs are prohibitive. Then you have the cost of capital to build a giant building that can support extremely heavy equipment for grow beds. You can't just use an old office building to support a couple thousand tons of equipment unfortunately.
But the thing is, right now there is so much arable land we can have luxuries like cattle and farmed wild game. In 80 years we may not be able to maintain those luxuries for 10.5 billion people without vertical farming. Especially since a lot of those people are starting to become more affluent on average. I wouldn't be surprised to see beef prices go above $20-30 a pound before the end of my life. Even accounting for inflation. Maybe VF will become economical by then?
Cattle are not a luxury, they are literally part of subsistence farming in many regions and an important part of the ecosystem. One of the reasons we have to use so much fertilizer is because we stopped letting cattle graze over the fields. Monocrop corn and soy fields are a far bigger problem for sustainability than people think, maybe as bad as industrial animal farming.
You are right! If you are a subsistence farmer you NEED to have cows, goats, pigs, and/or chickens to make up for the fact you can't grow 12 months a year and most of what you grow isn't edible by people. However subsistence farming is extremely land inefficient requiring 5 acres per person it feeds. This means that the maximum supportable human population is roughly 2.4 billion using subsistence farming.
Also, allowing animals to graze over fields used for growing food results in food borne illness and crop disease. (Usually anthrax and E-coli) Typically if you are going to use animal based fertilizers they must be sterilized and composted ahead of time unless you don't mind poisoning people.
Meat IS a luxury though. It's significantly more expensive per calorie than vegetable crops. (At least twice as expensive for the cheapest meat) It also uses about twice as much land as vegetable crops. Often subsistence farmers end up taking animals to market rather than slaughtering and eating themselves because they can get so much more food that way.
History shows that 3 things are important for food security: live animals for milk or slaughter, grain that can be stored, and any local food that can be easily dried. Before we react that food security isn't really a thing anymore, history has something to say about that as well. And yet the foolish are advocating for 2 of these safety nets to be disposed of.
Rain is mostly free if ocean is all that is downwind of you. Most of the West Coast of the United States is lush because the terrain catches most of the water that would otherwise flow much farther inland.
> Herein, a novel copper(II)–ethanolamine complex (Cu‐complex), which has a maximum water uptake of up to 300% and a water production rate of 2.24 g g−1 h−1 under natural sunlight, is reported.
* If you have high humidity, you almost always have plentiful rain and water around.
* If you're in a desert, then there's extremely little for any device to work with.
* It takes absolutely enormous amounts of air to extract meaningful amounts of water even in favorable conditions. * It takes a huge amount of energy, too.
* Any such scheme isn't reliable in any case, and especially unreliable when things are dry and you really need the water. It works best precisely when you don't need it.
* You don't want to drink water from any kind of dehumidifier. It may have started clean, but won't stay that way.