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Here's a link that describes the technology behind it: http://newsoffice.mit.edu/2013/how-to-get-fresh-water-out-of-thin-air-0830 http://newsoffice.mit.edu/2013

Here's a link that describes the technology behind it: http://newsoffice.mit.edu/2013/how-to-get-fresh-water-out-of-thin-air-0830 http://newsoffice.mit.edu/2013/how-to-get-fresh-water-out-of... ...and one showing the structure in detail: http://www.architectureandvision.com/projects/chronological/84-projects/art/492-073-warkawater-2012?showall=&start=1 http://www.architectureandvision.com/projects/chronological/... TLDR: Great for pulling moisture out of the air if the air already has a really high moisture content. Pretty much useless in other circumstances.

bryanlarsen 13y ago
According to the article, it's temperature differential that's important. So it works in the desert, which has 50 degree swings between day and night. Many places with high moisture content have much smaller swings in temperature, so it might not work as well in the jungle.
- clhodapp 13y ago
  Alternately, the article is incorrect/oversimplifying. It's pretty easy to see that it is at least oversimplifying with a simple thought experiment: Suppose we were to place a Warka Tower in an airtight with a humidity of 0% (no water in the air) and with an air temperature of 120°F. Then suppose we were to drop the chamber temperature to 40°F. By all accounts, this is a huge change in temperature for a human-habitable region to undergo (an 80°F change), so the tower should produce a LOT of water. However, because the air in the chamber has so little water actually in it, very little water will actually be produced. Ultimately, what makes the tower work well is a large temperature change and a high humidity.
  - sitkack 13y ago
    Step 1, find 0% humidity, where are you going todo that where people are living? Strawman.
    - ghshephard 13y ago
      Even the Desert Playa, which cracks your skin, and causes throats to dry out, has a low of 17% humidity, and an annual average of 45% humidity.
    - shadowmint 13y ago
      The point is that this is a fog harvesting device; it collects tiny droplets of water in the air efficiently. Fog is where you have > 70% (roughly) humidity, even if its only for a period of time. Deserts have highly variable humidity, often 10-30% during the day, and great at night; maybe 50% ... but you dont get fog in deserts, or, for that matter, in many other places. In some very specific regions, like Ethiopia, where you have misty mountainous regions; this is a useful device (see the article for the other very misty locations they talk about deploying this in). If you put it in your backyard, you'll probably get a tiny trickle from it occasionally, unless you live in Wales. The refrigerative water generators (http://en.wikipedia.org/wiki/Atmospheric_water_generator http://en.wikipedia.org/wiki/Atmospheric_water_generator) can work in places with relatively low humidity; these ones do not.
    - clhodapp 13y ago
      I believe that my argument remains a solid, semi-logical rebuttal (it does depend on some physical intuition) to the claim that we can fully trust the original article's claim that the effectiveness of the device depends only on the temperature differential at the location where it is deployed. At the very least, the claim needs to be demonstrated in the field or explained by some documented physical phenomenon before I'll completely trust it.
      - sitkack 13y ago
        Say that instead. Arguing that it only works in high humidity environments while using 0% humidity as your basis isn't sound.
    - aaron695 13y ago
      Antarctica. Space is another, but a bit more pedantic. But both are places that water would be valuable.
- shadowmint 13y ago
  Not really; the desert temperature differential isn't really relevant afaik; it's just to drive the air down below the dew point to generate droplets. If there's already a high ambient moisture content in the air, I can't see why it wouldn't work. This is a just a structure to collect droplets, and there are plenty of those in the jungle.

bryanlarsen 13y ago

According to the article, it's temperature differential that's important. So it works in the desert, which has 50 degree swings between day and night. Many places with high moisture content have much smaller swings in temperature, so it might not work as well in the jungle.

clhodapp 13y ago
Alternately, the article is incorrect/oversimplifying. It's pretty easy to see that it is at least oversimplifying with a simple thought experiment: Suppose we were to place a Warka Tower in an airtight with a humidity of 0% (no water in the air) and with an air temperature of 120°F. Then suppose we were to drop the chamber temperature to 40°F. By all accounts, this is a huge change in temperature for a human-habitable region to undergo (an 80°F change), so the tower should produce a LOT of water. However, because the air in the chamber has so little water actually in it, very little water will actually be produced. Ultimately, what makes the tower work well is a large temperature change and a high humidity.
- sitkack 13y ago
  Step 1, find 0% humidity, where are you going todo that where people are living? Strawman.
  - ghshephard 13y ago
    Even the Desert Playa, which cracks your skin, and causes throats to dry out, has a low of 17% humidity, and an annual average of 45% humidity.
  - shadowmint 13y ago
    The point is that this is a fog harvesting device; it collects tiny droplets of water in the air efficiently. Fog is where you have > 70% (roughly) humidity, even if its only for a period of time. Deserts have highly variable humidity, often 10-30% during the day, and great at night; maybe 50% ... but you dont get fog in deserts, or, for that matter, in many other places. In some very specific regions, like Ethiopia, where you have misty mountainous regions; this is a useful device (see the article for the other very misty locations they talk about deploying this in). If you put it in your backyard, you'll probably get a tiny trickle from it occasionally, unless you live in Wales. The refrigerative water generators (http://en.wikipedia.org/wiki/Atmospheric_water_generator http://en.wikipedia.org/wiki/Atmospheric_water_generator) can work in places with relatively low humidity; these ones do not.
  - clhodapp 13y ago
    I believe that my argument remains a solid, semi-logical rebuttal (it does depend on some physical intuition) to the claim that we can fully trust the original article's claim that the effectiveness of the device depends only on the temperature differential at the location where it is deployed. At the very least, the claim needs to be demonstrated in the field or explained by some documented physical phenomenon before I'll completely trust it.
    - sitkack 13y ago
      Say that instead. Arguing that it only works in high humidity environments while using 0% humidity as your basis isn't sound.
  - aaron695 13y ago
    Antarctica. Space is another, but a bit more pedantic. But both are places that water would be valuable.
shadowmint 13y ago
Not really; the desert temperature differential isn't really relevant afaik; it's just to drive the air down below the dew point to generate droplets. If there's already a high ambient moisture content in the air, I can't see why it wouldn't work. This is a just a structure to collect droplets, and there are plenty of those in the jungle.