>Eventually it’s hoped that buildings will be completely self-sufficient, or “water neutral,” using the same water over and over, potable and nonpotable, in a closed loop.
I can't see that working have they not heard of evaporation? It would work but need a top up. It's a good idea to save water but it may need some fine-tuning for technical reasons and for acceptance by people.
>>Eventually it’s hoped that buildings will be completely self-sufficient, or “water neutral,” using the same water over and over, potable and nonpotable, in a closed loop.
So a condo/apartment has it's own elevators, solar rooftop, and now a hi reliability water recycling system that can support a few hundred units.
> which was tested on an MIT building rooftop. The system delivered pure water that exceeded city drinking water standards, at a rate of 5.78 liters per square meter
I would be very interested to see data on this vs. sunlight and climate conditions, in what weeks/month of the year they tested it. I think its effectiveness would be highest at MIT's location from late April to end of September and considerably less in colder/overcast/less sunny weather and winter.
> Another ten cents, if it is largely water based, what about letting the water evaporate?
They could run it through reverse osmosis, which is already commonly done in industrial scale. This would not get rid of the all the water, but just take it down 90% would be enough.
> I don't think they are boiling it. It read to me like they're just evaporating the water in some efficient way, rather than boiling
There are definitely efficiencies to be had, though I don't know enough of the math to judge one vs. the other. During my brief patent career, I wrote the patents for a distillation system where the main elements involved heating water that was distributed across rotating blades (heat + surface area + air movement) to evaporate the water. When the water was collected, it passed through a heat exchanger that exchanged heat with the in-flowing water. The result was a very efficient system on a small scale, at least.
"They have developed a completely passive system that is based on a foam-like material that draws moisture into its pores and is powered entirely by solar heat."
> Basically a 100' square catch basin on the roof of the building would provide all the water they need. Noise.
Which raises the question: Why don't they just do that? I'd imagine it would be less effort to process, and even though you do need to have a buffer against low rainfall periods, water is one of the easiest things to store.
At first pass, I would guess that something like this would primarily be useful in places with naturally high humidity, which aren't likely to have a shortage of water in the first place, no?
Maybe the argument is that the natural sources of water are dirty, and extracting from the air is automatically clean and safe to drink, but it still seems like it may be more resource efficient to invest in water treatment, not a fleet of dehumidifiers.
After the water rationing I heard happening in South Africa’s capital, I took it upon myself to research commercial water from air extractors. A dehumidifier essentially.
There’s a company out in Arizona that had an article published in wired. Zero Mass Water. The article intrigued me. I lived close enough to the ocean, would it work?
I had a few panels installed on my roof. I can yield somewhere between 3-15 liters per day if the conditions are right. I can store 90 liters total. I use it as drinking water in my home. I no longer drink from municipal tap water as a result. Yes I shower with it, but I’m not really ingesting as much.
Point is I did the panels for the exact same reason this article is the mentioning water wars coming up. At some point we’ll have to be rationing water in cities and I don’t want that for myself or my family.
> it should come as no surprise that the energy you get out by wasting your fresh water isn't as much as the energy you put in to get it in the first place
Agreed, but maybe the effect can be used to alleviate the cost of getting the fresh water? For example, it doesn't cost so much to heat up a building once it's been heated up if it has heat exchangers in its HVAC: the output heat is used to heat up incoming hot air. A wasteful process can be made more efficient with stupid tricks.
I would love that! They make things like that for electrical outlets so you can see how much power things (lamps, clocks, etc) consume. It would be awesome to see the same thing for water. California is in a major drought right now and I'm very curious what in my house uses the most water.
You will have to condense it from steam. Doable, but not without cost. It's also highly mineralised, and you will have to acid wash hardware frequently.
Could the need to manually refill water periodically be replaced by a condenser that constantly pulled ambient moisture out of the air? The total amount of water they are talking about is not very much. This seems like it could be solved without constant topping off.
> Last year, he formed a company called Water Harvesting that this fall plans to release a microwave-size device able to provide up to 8 liters per day. The company promises a scaled-up version next year that will produce 22,500 liters per day, enough to supply a small village. “We’re making water mobile,” Yaghi says. “It’s like taking a wired phone and making a wireless phone.”
Any ballpark estimates on the cost for a residential use unit? i.e. 200L-1000L/day
Also, is it feasible for this to markedly effect downstream areas?
i.e. If there's eastwardly wind flowing through Nevada where machines are extracting humidity at an extreme scale, how might the 30%+ humidity-requiring plants (i.e. that Jamaican Yerba) in Utah hold up?
water wars 2.0, version: air.
humidity credits & humidity sink surveillance with humidobfuscation 'consultants'.
Wow, I was under the impression that atmospheric water harvesting (AWH) was extremely inefficient. I don't have any numbers but things like [1][2] seem to indicate that AWH is currently not very useful.
The paper doesn't seem to (if I read it correctly) actually address this directly, instead it talks about how much energy is needed to extract water at different relative humidity levels and factors in the potential energy generated through solar panels. It also looks at the usefulness of this process given factors such as existing access to clean water (or lack thereof) and population. I didn't looking beyond the 'Methods' section, I hope I didn't miss anything here.
I can't see that working have they not heard of evaporation? It would work but need a top up. It's a good idea to save water but it may need some fine-tuning for technical reasons and for acceptance by people.
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