Hacker News Reader

Comment by maxklein | Hacker News Reader

I'm somehow very doubtful that this works effectively. If it is so effective, then why is it so rare? Probably it keeps the goods somewhat cool, but not particularly cool.

View on HN

It's not as cold or as convenient as a standard plug-in refrigerator. If you're living in an area with access to HN, congratulations, you have electricity, which eliminates the need for something like this in your area unless you're really trying to save on energy. Another contributing effect is probably that not everybody understands the concept of this design. Much of the world is under-educated, with limited access to knowledge like this.

The operating principle isn't rare. We use swamp coolers here in Arizona all the time. But I wouldn't use them to store food.

There are a number of limitations to them. The maximum cooling you'll get is 20F less than ambient, and that is entirely dependent upon humidity. So these only work in places that are extremely dry (yet also have plentiful water to run these coolers).

With the "pot in pot" method I wonder how they circulate air. You need a fairly constant supply of dry air for evap cooling to work. I'd imagine a porous exterior pot (think whiffle ball) filled with a spongelike material.

> The maximum cooling you'll get is 20F less than ambient, and that is entirely dependent upon humidity.

Any idea about the specific physics here? I'd love to see some equations to help explain this system (and the swamp coolers we use here in rural CA too).

Equations: http://en.wikipedia.org/wiki/Wet-bulb_temperature#Temperatur...

Ka-zaa!

It is so rare because it is pretty useless, inefficiently and there is no need for it in the proposed regions. People there desiccate their food or use spices like chili to make sure it stays esculent for a longer time, They don't have much water, so in my opinion it is pretty stupid to waste it for food if they have much better ways to conserve.

Reply on news.ycombinator.com