Refrigerator without electricity

Project Overview:

Mobah Rural Horizons, is a Rural Development and Consulting Organization that designs, invents, and disseminates appropriate technologies for poor rural areas. The project is a fresh foods preservation system that uses two clay pots. This system requires no electricity supply to preserve and prolong the storage life of perishable fresh food items.

Problem Addressed:

For people who live in hot climates with little electricity, food spoils quickly. Produce spoils in within three days without refrigeration, forcing farmers to rush their crops to the market and sell them at undervalued prices. This has a lot of consequences to the farmers, and their families, because it affects their village life and leads a decrease in income in the poor rural areas. For Kano City, which is around 60 miles from many farmers, the fresh produce that is grown rots along the way, causing its farmers to earn smaller profits and provide for fewer people.

Refrigeration is a method for storing foods around the world, but places in Africa like Kano City do not have the resources to support a stable supply of electricity to make refrigerators a viable option.

Technology Solution:

Mohammed Bah Abba designed an elegantly simple food storage device that is made up of two earthenware pots which utilize the principles of evaporation to create electric-free refrigeration. In between the two pots is a layer of fine, wet, river sand, and on top is a moist jute bag. When kept in a dry, well-ventilated, and shady location, water evaporates, cooling the inner container. As a result, Mohammed’s desert refrigerator allows produce to stay fresh for weeks, so less food is wasted, and farmers are able to increase their profits so that they can continue to provide for their communities. Mohammed sells around 30,000 coolers a year to farmers and other people who want to preserve food for their families and communities.

About The Tech Museum of Innovation

The Tech Museum is a hands-on technology and science museum for people of all ages and backgrounds. The museum—located in the Capital of Silicon Valley —is a non-profit, experiential learning resource established to engage people in exploring and experiencing applied technologies affecting their lives. Through programs such as The Tech Challenge presented by Cisco, our annual team-design competition for youth, and internationally renowned programs such as The Tech Awards presented by Applied Materials, The Tech Museum endeavors to inspire the innovator in everyone.

According to, this is how you build one:

"Materials and Tools Required
two terra cotta pots with a 2-3 inch difference in diameter. The smaller pot should be glazed and preferably lacking a drainage hole. If the inner container is double glazed (on its inner and outer walls), non-potable water—say seawater—can be employed.
a bag of sterile sand
a square of burlap cloth large enough to cover the top of the inner pot
a trowel
Building It
1. If your pots have drainage holes, plug them with a bit of cork, caulk, or other waterproof material. If you don’t, moisture from the sand will seep into the lower pot and immerse the stored goods or seep out the bottom of the larger one.
2. Put down a one-inch deep, level layer of sand in the bottom of the large pot. Set the smaller pot on top of that layer and center it in the larger one. Make sure that the smaller pot’s lip is even with the larger one’s.
3. Fill sand in around the sides of the of the two pots, leaving about an inch of space below the lip.
4. Pour cold water over the sand until it is thoroughly saturated. Put your food into the smaller pot. Cover that with a burlap cloth, also soaked with water. That’s it! Just be sure to refill the water regularly, about once or twice a day."


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