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Scientist Creates Self-Filling Water Bottle

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Re: Scientist Creates Self-Filling Water Bottle

#41

Post by andrewcooke »

Jabbles wrote: post #25
andrewcooke wrote: post #10

Earlier quoted context omitted.

i think you're confusing collecting area with airflow cross-section. they're completely different things, unless somehow the air is blowing through the side of the (solid) bottle.

Not really. This volume of air has to make contact with the bottle, whatever the collecting area's shape. Imagine loosely fitting a tube around the neck of the collecting area. All the air has to pass through that tube.

no, i'm saying that only a small fraction of the incident air will touch the surface. most will flow around - probably laminar flow containing a stagnant area of higher pressure directly in front of the obstacle.

you are calculating the swept volume. but only a small fraction of the swept volume "makes contact" (ie is roughly within the mean free path of a water molecule) with the collecting surface (which appears to be necessary here for water to be extracted).

with netting your argument is closer to being correct. but this is an impervious bottle, not a net.

if you implemented the tube you suggest (and i understand that was simply an illustration to explain swept volume) then pressure would increase in the tube slowing flow and/or flow would be predominantly around the edges, with, again, a stagnant higher pressure region in the centre.

Re: Scientist Creates Self-Filling Water Bottle

#42

Post by whatshisface »

ipetepete wrote: post #9

So, now the real question is: How long until we have a self filling beer bottle?

Well, if we assume that any source of alcohol could be counted as beer, this device could be constructed by combining the water generator with a colony of modified algae (or an ecosystem of carb leaking algae and yeast) combined with some sort of membrane that allows alcohol through but not water. (Or a Brownian motion powered still).

That sounds pretty hard, but it would be a safe bet to say you could buy one within fifty years. Maybe longer if you want something nicer than pure ethanol.

Re: Scientist Creates Self-Filling Water Bottle

#44

Post by derekp7 »

GuiA wrote: post #39
ggchappell wrote: post #36

If I might channel my inner grumpy-old-man for a moment: I find it curious that people who design nifty new devices are regularly referred to as "scientists". This is not science; it is engineering . Why not call it that?

I can't wait to hear what you'll have to say when someone will call themselves a "computer scientist" ;)

I like what Cliff Stoll had to say about this... "The first time you do something it’s science. The second time it’s engineering. A third time it’s just being a technician" -- Ted Talks, 18 minutes with an agile mind.

Re: Scientist Creates Self-Filling Water Bottle

#45

Post by mylittlepony »

james4k wrote: post #17
eykanal wrote: post #8

> Sorenson notes there is more than three quadrillion gallons of water in the air, which is essentially a massive untapped resource. For what it's worth, air with low humidity can be pretty damaging. Lots of materials would become excessively brittle at very low humidities, causing them to break easily. This interesting white paper [1] suggests that, for most materials, the optimal humidity is between 40-60%. Still,…

This might be true, but the atmosphere is also very good at reabsorbing water. Especially if humidity levels would be lower than normal.

I thought that would happen, it's kind of intuitive.

Re: Scientist Creates Self-Filling Water Bottle

#46

Post by novaleaf »

Someone wrote: post #29

Background info: http://en.wikipedia.org/wiki/Air_well_(condenser) The device in India shown there produces 15 liters of water per square meter per year. The surface area of a bottle is, say, 500 square cm, or 1/20 of a square meter. That would produce about a liter in a year. http://www.iimahd.ernet.in/publications/data/2005-01-05gshar... talks of 0.042 liter per square meter per day, in extreme.y high humidity. Cle…

if you read further down in the wikipedia article, it shows zibold's collector which produced about 0.9 liters/square-meter/day

just pointing out that efficiency may be better than what you are estimating.

Re: Scientist Creates Self-Filling Water Bottle

#47

Post by harold »

SiVal wrote: post #28
hcarvalhoalves wrote: post #16

Earlier quoted context omitted.

I guess the airflow is to make it more efficient. In high humidities, you can easily collect 1 liter potable water with a 3m2 plastic sheet, a clean recipient, a hole in the ground and some sunlight, or just hot weather. It's an old survival trick. His apparatus is a kind of upgrade.

The plastic sheet process is different from the one in the article. In the case of the plastic sheet, you are baking the water out of the ground, not extracting it from ambient air. It seldom works well in practice, because you get a little condensation under the sheet, but it's not enough to run in rivulets into the jar, and when you DO get a few drops in the jar, the same process that is baking the water out of the…

I spent some time learning from a respected survival expert who claimed the 'solar still' was not an efficient use of one's energy. I tried it out a couple of times anyway and proved to myself that he was right.

What did work fairly well was a transpiration bag [1]. It took a few bags to get a meaningful supply of water and one needs to be careful about the foliage used.

[1] http://www.youtube.com/watch?v=q2EBiA0Csts

Re: Scientist Creates Self-Filling Water Bottle

#49

Post by nickbarone »

ars wrote: post #32
nickbarone wrote: post #18

My question is what kind of contaminants (or none!) this process picks up - If you're getting your water from a polluted atmosphere (say, LA), what kind of pollutants end up in your water? Or does it produce "ultra-pure" water, leading to weird health risks like hyponatremia?

You won't get hyponatremia from overly "pure" or distilled water. The amount is water is utterly dwarfed by the amount in food. If there are pollutants in air they will be in the water, but it's not a actually a problem because, although they might be bad to breath, most air pollutants are harmless when eaten. Carbon (soot), Ozone, NOs, sulfur dioxide (smog), etc are harmless to eat.

Interesting. Are there any that are the other way around - dangerous when eaten, but not when inhaled?

I'd imagine it'd have to do with the digestive ecosystem, if there were any that worked that way.

Re: Scientist Creates Self-Filling Water Bottle

#50

Post by ajuc »

ars wrote: post #34
eykanal wrote: post #8

> Sorenson notes there is more than three quadrillion gallons of water in the air, which is essentially a massive untapped resource. For what it's worth, air with low humidity can be pretty damaging. Lots of materials would become excessively brittle at very low humidities, causing them to break easily. This interesting white paper [1] suggests that, for most materials, the optimal humidity is between 40-60%. Still,…

Any water you capture will just be sent back into the air later. Think of what you drink - all of it end up in the air or land again later.

The important thing is the speed of capturing and returning the water to the air, not only the fact that it will be eventually returned.

When we change one or both of the speeds - the balance shifts, and the effective humidity of air changes to new stable value.

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