Article on a 3D printed water from air device

[bmAvon]

I saw this and thought of you, with the caveat that my scientific knowledge isn't good enough to judge how useful this actually could be and I can't see any mention of what the heating/power source is.

This portable, 3D-printed device can pull drinking water out of thin air
https://www.popsci.com/technology/water ... r-project/

[ForgeCorvus]

This is the forth "Water from air" device I've seen, they never live up to the hype.

One of the fundamental flaws is you need humid air so there is water to extract.

I can't see anything about the power input either.


My limited science knowledge questions heating the air to get water to condense...... I thought warm air holds more moisture then cold?

[Frnc]

Yes, warm air can hold more water vapour than cold air. There are two types of humidity - absolute and relative.
Absolute Humidity is the actual amount of WV, measured in kg/m3.
Relative is the degree of saturation, which varies with temperature.

For example, 60% RH at 25°C is AH of 13.8 g/m3, or 0.0138kg/m3. I prefer g/m3.

Now if we take the actual amount of WV, as shown by AH, and reduce the temperature, say to 20°, RH increases to 80%. At 16°, RH is 100%. This is called the dew point, and dew forms because the air has cooled so much it can no longer hold all the water it contained.

Rain and clouds are a bit more complicated, in that seeding also takes place, around tiny dust particles.

Another interesting thing is that when water vapour condenses, heat is released. This is the exact opposite of why if you are sweating, or if you are wet and in the wind, you cool.

Reason - to evaporate, water needs energy, so it takes it from its surroundings, causing temperaure to drop. The opposite happens with condensation.

Can machines produce drinking water from air? Of course. You need humid air, power, and you cool the air to create condensation. Power useage will likely be significant.

And it won't be automatically drinkable. You still need to filter it. Same with rain water caught on a clean tarp. It can contain bird droppings, bacteria and other nasties.

[jennyjj01]

There are some practical atmospheric water generators, using different techniques and maybe using dessicants which need to be heated to extract the water.
But the energy cost is usually high and the yield is low. I can't envisage the 3d printed device, barely described, being anything like useful in the UK. The yields sound absurdly unachievable.

I don't think it's coincidence that the article is posted on a page littered by paid ads. I.e. clickbait content.