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Self-filling water bottle turns humidity into drinking water for cyclists

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Re: Self-filling water bottle turns humidity into drinking water for cyclists

#11

Post by DanBC »

Someone wrote: post #7
mslev wrote: post #6

Earlier quoted context omitted.

I can see this being pretty useful for long touring rides, where you're riding for a long time but not necessarily pushing very hard.

"After more than 30 experiments, I finally achieved a constant drop-flow of one drop of condensed water per minute" Guessing the diameter of a drop at 1mm, and assuming it to be cubic, that is 60 cubic mm per hour. Rounding up, we get 1 cc per hour. A U.S. teaspoon is just under 5 cc. Alternatively, get a small cup of water every 24 hours. There can be about 30 cc of water in a cubic meter of air, so you would have t…

Why did you estimate the size of a drop as being so small?

Re: Self-filling water bottle turns humidity into drinking water for cyclists

#12

Post by miahi »

NickNameNick wrote: post #4

I wonder what the power requirements are, The cooling system has to be cooling the air that passes through it down to the dew point, if the ambient temperature and the dew point are too far apart, it's going to consume too much power to be practical.

It also looks solar powered-only, so its efficiency is not better when the dew point is closer (night/morning).

Linking a small solar cell (I would say ~1W from the shown surface) to a Peltier element (known power hog, a really small one takes at least 4W) is not a solution for efficiency.

Re: Self-filling water bottle turns humidity into drinking water for cyclists

#15

Post by NickNameNick »

miahi wrote: post #12
NickNameNick wrote: post #4

I wonder what the power requirements are, The cooling system has to be cooling the air that passes through it down to the dew point, if the ambient temperature and the dew point are too far apart, it's going to consume too much power to be practical.

It also looks solar powered-only, so its efficiency is not better when the dew point is closer (night/morning). Linking a small solar cell (I would say ~1W from the shown surface) to a Peltier element (known power hog, a really small one takes at least 4W) is not a solution for efficiency.

Wolfram alpha says it takes ~1.3kj to change the temperature of 1m^3 of air by 1 degree C. Obviously this will vary enormously with temperature and humidity, but it gives us a number to work with.

Wikipedia, and a post by 'someone' tells us there is ~30cc of water per cubic meter of air at 100% humidity and 30c. (This could be a reasonable set of envoronmental conditions in Washington DC for example).

The mass of water in 100% humidity air is

28c 27.22g http://www.wolframalpha.com/input/?i=mass+of+water+in+1+cubi...

30c 30.34g http://www.wolframalpha.com/input/?i=mass+of+water+in+1+cubi...

So we can extract ~3g, or 3cc of water from saturated air, with the use of ~2.6kj (assuming 100% efficiency, which is unlikely)

Some of the highest power density batteries I've handled are 5 cell, 5500mAh li-poly batteries for model aircraft use, with a total energy capacity of around 180kj,

Or ~ 200g of water.

I think I'd rather carry a water bottle.

Re: Self-filling water bottle turns humidity into drinking water for cyclists

#18

Post by notfoss »

e12e wrote: post #14
Icybee wrote: post #13

If you cycle through areas with a lot of traffic, could the water end up contaminated with vehicle exhaust?

I'm pretty sure most harmful exhaust would be more harmful when breathed in, than when drunk?

Sorry to be pedantic, but if you are pretty sure, then how come you end your sentence with a question mark?

Re: Self-filling water bottle turns humidity into drinking water for cyclists

#19

Post by iterationx »

notfoss wrote: post #18
e12e wrote: post #14

Earlier quoted context omitted.

I'm pretty sure most harmful exhaust would be more harmful when breathed in, than when drunk?

Sorry to be pedantic, but if you are pretty sure, then how come you end your sentence with a question mark?

You don't sound sorry.
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