This credit crunching fridge is a sure way to be sure your beverages will stay chilled in the hottest of heats. It's much greener than your average electrical fridge and will work anywhere where there isn't a lot of humidity.
The pot in pot refrigerator or Zeer was made by Professor Mohammed Bah Abba, though there's evidence it was in use in early Egypt. It works on the principle of evaporative cooling.
You will need:
Two terracotta pots. One has to fit inside the other with an inch or so between all the way round.
A towel/cloth big enough to go over it
5-10 minutes, maximum!
Step 1: First pot
Firm down the sand before putting your second pot in.
Step 2: Filling the pot with sand
The last image shows me stopping filling a little way down from both rims - the pots are pretty much flush with each other.
Step 3: Watering
The terracotta pot is porous, so it wicks the moisture into the external pot.
The sun and wind evaporate the water which causes heat loss - effectively cooling the inside.
To cover, use an old towel and wet this as well. You could put one end of the towel in a reservoir (a bowl of water) and it would continue to wick water up onto the top and evaporate causing more of a temperature drop.