For $2 you can keep your beers cool and the third world can eat salad.

Anyone who’s spent time traveling in the third world knows that one of the biggest obstacles to getting anything done are the power cuts. Everything gets plunged into darkness, your email gets lost and unless the restaurant has a noisy generator, your banana milkshake aint coming any time soon.

Power cuts are also one of the reasons that it’s easy to get sick in the third world. Food warms up inside refrigerators and the bacteria starts to multiply. By the time it’s been cooled and warmed a dozen times you have enough dysentery pathogens to enable you to write a thesis on third world bathrooms.

So full respect to Mohammed Bah Abba, a Nigerian man who worked out how to produce a refrigerator for the poor of the world that costs only $2. The design is simplicity itself and makes you wonder why no one else thought of it before; you put a clay pot inside another pot that’s a little larger, fill the gap with sand and pour water on the sand twice a day. You cover the pots with a wet cloth and as the water inside evaporates, all the heat goes with it.

So in places like Nigeria where vegetable wilt and rot in the space of a day or two, food can now be kept fresh for a couple of weeks. It also spells an end to those market stalls you always see with thousands of flies crawling over the mangoes you wanted to buy.

But spare a thought also for the traveler living out in the woods. Sure, he’s got his little plastic tent, jacket potatoes in the fire, maybe even a wind-up radio for some late night blues classics – but where’s the cool beer? A quick trip into town to buy a couple of pots, some sand from the river bed and you can drink beer at 15 degrees. Not ice-cold, perhaps, but good enough for Guinness.

The pot-in-pot refrigerator is called a zeer and here’s how you make one