A REFRIGERATOR THAT RUNS WITHOUT ELECTRICITY
permaculture.org.au
By Craig Mackintosh

Original Link

Sometimes there are simple solutions to universal needs that don’t require coal fired electricity, fossil fuels, or even solar panels or wind turbines.

Around a third of the world’s population have no access to electricity. If you’re like me, you’ve spent your entire life being able to plug in. Do we ever give a thought to what life would be like if the various appliances we’ve come to rely on were to suddenly stop working? One of the most energy guzzling appliances in our carbon footprint portfolio is the refrigerator. But, unplug it, and the quality of your life will suddenly deteriorate. Take that thought, and imagine living in a hot dry country in Africa, without electricity, where food quickly wilts and rots in the sun, aided by onslaughts of flies.

One modern day genius, mindful of this basic need to preserve food, has solved the problem for many. Mohammed Bah Abba, a Nigerian teacher, invented the ‘device’ -- a refrigerator that doesn’t require electricity!

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.

Inventing the refrigerator in 1995, Mohammed distributed thousands around Nigerian communities during the late 1990s (initially for free to get the word out, then later at just production-cost price), and subsequently won the Rolex Award for Enterprise in the year 2000. It has improved the lives and health of thousands. Less work can translate into more education for children, and small farmers who were before losing large proportions of their harvest are now able to earn a better income. Another knock-on benefit is improved health due to better preservation of vitamins, as well as a reduction in health problems like dysentery due to the separation of food and flies.

It seems that not all the answers to life’s needs have to come with a plug and instruction book.