4 ms·

> a "machine that makes water out of air" Isn't that just your typical air-con unit?

• mchannon 3y ago
  Exactly. But you will find dozens of examples in a google search of people who somehow think they've solved the world's water woes by collecting condensate off a disassembled A/C or dehumidifier, and ignorant uncritical news reporters buying it hook line and sinker. Collected funding, even had a whole embarrassing incident at Cal involving the freshman engineering class a few years ago. There is definitely a need for clean water out of air, but it's got some subtle limitations: you don't need it when it's already raining, and the further you get from that condition, the less well dehumidifiers work in terms of gallons produced per kwh consumed. Below 50% RH, you're getting bupkis for condensate. Most of that energy is spent cooling off air but not quite cold enough to get it to leave its moisture behind. Here's an easy thought experiment next time you run across one of these "inventions". If a cubic foot of air at 40% humidity contains .24 mL (sorry for mixed units) of water, give them the benefit of the doubt and say their setup is 100% efficient for pulling every last molecule of water out of air. and it runs on a 28cfm computer case fan. How many gallons per hour would that be? 0.1. The reason these suck is not that they don't work in dry conditions (though they don't), but that they don't move enough air to be useful.