I love stories of successful implementation of “appropriate technology“. Here’s a refrigeration device that uses no electricity being set up in northern Nigeria. It is built by placing a clay pot inside a slightly larger pot and filling the gap with sand. By wetting the sand, the evaporative properties create a significant cooling effect (much like the old water bags on the front of jeeps kept water cool). Food that used to last only days, now lasts weeks.
A side issue is that young girls that used to be saddled with the daily duties of retrieving fresh produce for the family, now are increasingly able to attend school.
Tinaja Labs 
Inspirational story. And a great idea on how to keep all that beer cold at Big Sandy.