Notes for surviving the apocalypse in style:
From a family of pot-makers, Mohammed has made ingeniously simple use of the laws of thermodynamics to create the pot-in-pot refrigerator, called a Zeer in Arabic.
Here’s how it works.
You take two earthen pots, both being the same shape but different sizes, and put one within the other. Then, fill the space between the two pots with sand before pouring water into the same cavity to make the sand wet. Then, place food items into the inner pot, and cover with a lid or damp cloth. You only need to ensure the pot-in-pot refrigerator is kept in a dry, well-ventilated space; the laws of thermodynamics does the rest. As the moisture in the sand evaporates, it draws heat away from the inner pot, cooling its contents. The only maintenance required is the addition of more water, around twice a day.
To give an idea of its performance, spinach that would normally wilt within hours in the African heat will last around twelve days in the pot, and items like tomatoes and peppers that normally struggle to survive a few days, now last three weeks. Aubergines (eggplants) get a life extension from just a few days to almost a month.