This is in response to a real world problem, and it's an already baked idea applied to a new problem, so I may be breaking a few forum rules. However, this application is only half baked, and in a good cause, so I'll post anyway.

Geekcorps (see link) is installing computer infrastucture in outback Mali and is having problems with dust and their CPUs running over-temperature. They are seeking a low-cost, low tech solution.

My idea is to use something based on the Coolgardie meat safe (see link). This was ubiquitous in the equally hot Australian outback before electricity was available for refrigeration.

Coarse fabric, suspended from a tray of water and draped over the sides of the safe provide evaporative cooling. The safe works best if kept in the shade, in a breezy location. A drip tray collects excess water, which is used to refill the top tray.

With this version, the computer would be placed inside the safe. This solves the dust problem, but if the safe is too small, this would make the temperature situation worse, because the limited available air would rapidly heat, without sufficient evaporative cooling effect. Whether or not this solution works depends on how large the safe would need to be to counter this effect and provide a benefit. This could be determined by experiment, or a refrigeration engineer should be able to provide a rough estimate (any takers?). The temperature only needs to be reduced sufficently to bring the CPU within its designed operating range. Of course, other environmental factors, such as humidity also come into play.
-- goldilox, Mar 30 2005

Coolgardie safe http://projects.pow...om/rat/cool_fct.htm
Coolgardie safe description / history [goldilox, Mar 30 2005]

Geekcorps http://mali.geekcor....php3?id_article=67
Geekcorps temperatue problem [goldilox, Mar 30 2005]

This is a similar approach to a bong cooler, which can be used as an evaporative alternative to the radiator in a watercooled PC. The warm water coming off the cpu is sprayed out of a showerhead into a catching tray; heat is lost through rapid evaporation and the water that lands in the tray can be cooler than ambient. Doesn't keep dust out though.
-- david_scothern, Mar 31 2005


Something like that might work for these guys, as long as the flow could be kept fairly low. They probably don't have any kind of pump, so it'd be gravity on the way down, hand dipper on the way up.
-- goldilox, Mar 31 2005


I emailed Geekcorps to suggest that they used laptop CPUs to attack the problem from another angle. They dump less heat and are rated to run at higher temperatures than their desktop counterparts. Haven't had an answer yet though.
-- david_scothern, Mar 31 2005


That's probably the best solution, if they can get CPUs at the right voltage and in the right package for their motherboards. If they put out an appeal, they'd probably get them for free, and the postage would be negligible.
-- goldilox, Mar 31 2005



random, halfbakery