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I like it as a proof of concept, would love to see a more serious engineering effort to demonstrate what real world costs, durability, and aesthetics might look like (if significant portions of indoor walls are going to be covered in this stuff, it needs to be able to look decent).
Turn myself into a moisture farmer if you will.
But then I wonder, would it be a problem if everyone did it? Would it cause humidity to drop in a bad way?
Typical 50% RH at ground level is ~7g/kg air, air is roughly 1kg/m^3, so between the surface and the planetary boundary layer (let's say 1km) is about 7L of water per m^2 of surface. Moving along at ~3m/s means 21L/s passes by each meter of fence line.
PBL probably mixes after about 50km, so it takes ~5 hours to normalize after you pull out water at ~5 knot wind speed. If you want to not make a dent, means you can pull less than 1L per m^2 per hour, or about 8m^3 pear, which is about 8x the yearly requirement for farmland.
So, you can irrigate a farm and your neighbors would mostly be fine.
(math not checked)
For a farm, say growing almonds (notably water intensive, but a reasonable first pass), you need about 4 acre-feet per acre per year, which would cost... hmm, somewhere in the very rough ballpark of $200k / yr.
That might put the economics of almond farming substantially in doubt, given that an acre of almonds might yield a value (revenue, not profit) of, say, $10k on a good year.
(To your point, it's almost impossible to imagine we'd be able to operate it at a scale that makes a genuine impact, but these are all chaotic systems and a couple percent here and there can compound to keep things on the right side of the phase shift.)
As to your question, would it be a problem if everyone did it -- it depends obviously on your definition of "problem", but consider that most people doing this have no way to dispose of the water they take from the air except by putting it back in the air. It might increase regional power consumption, and smooth out nightly shifts in atmospheric humidity, but unless there is a new river running to the sea, the average atmospheric humidity will remain the same.
Hi! This is friendly neighborhood energy conservation law speaking!
You can't just get moisture out of the atmosphere without investing energy. This device works backwards, it exploits the difference in humidity between the indoors and the outdoors. The source of this difference is ultimately the stored energy in food. Humans burn the food and release water vapor as a result, raising humidity inside the building.
isn't below 40% "bad"?
https://midwesthvacpro.com/what-should-indoor-humidity-be-a-...
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