Modern refrigeration uses quite a bit of electrical power (especially the older refrigerators made before the advent of Energy Star). And, they require constant availability of electricity, which, in areas with lots of brown-outs and black-outs can be a real issue.
There is a practical small-scale refrigeration solution that anyone make themselves for very little money, and best of all it uses no electricity at all. The device is called a “Zeer Pot” or “Pot-in-Pot Evaporative Refrigerator”, which made of two different sized clay pots with a layer of wet sand in between. The pot cools as the water evaporates which works best in warm, dry climates.
Evaporative coolers like the Zeer Pot have been around the Old Kingdom of Egypt, around 2500 B.C. For centuries in Spain, botijos, porous clay containers, are used to keep and to cool water and in the 1890s gold miners in Australia developed the Coolgardie safe, based on the same principles.
A Zeer Pot will keep items inside it about 15 to 20 degrees cooler than the surrounding area. This makes it ideal for storing fruits and vegetables, making them last much longer. You can cool drinks in a Zeer Pot, and it’s also great for storing butter to keep it cool and fresh yet not as hard-as-a-rock.
If you don’t already have the materials at hand, they can be purchased at any fair sized hardware store. You’ll need two unglazed terracotta clay flower pots of different sizes – The small one should be big enough to hold whatever you want to keep cold, and the large one should be big enough to hold the small one with about 2″ – 3″ around the edges; some sand; and a lid that fits the inner pot (this is optional).
First, cover the drain holes in each of the pots – this can be done with a sturdy, waterproof tape or epoxy, etc. Add a layer of sand to the larger pot, smoothing it out as you go. You need enough in the bottom of the large pot so that you can set the small pot inside it and have the lips of the two pots be on the same level. In fact, you should really have the inner pot just a tiny bit higher. Continue filling the space until you’ve reached the upper edges, and pack the sand down as much as you can.
Then add water. You’ll want to pour the water slowly onto the sand while constantly moving your water container–you don’t want to flood just one area. Keep filling until the sand is soaked, but don’t fill it so much that water is standing.
Move your Zeer Pot to its permanent home–it should be in a shaded location with good air circulation–such as a counter near a window. If you have a lid that fits the inner pot, use it, or just cover it with a damp piece of cotton cloth.
If the top half of the pot is turning dark, that’s a sign you need to add more water. You’ll need to water the sand once a day, usually in the morning. Try to elevate the entire pot on a wire rack to increase the amount area of the pot that is exposed to airflow.
A Zeer Pot is not a replacement for a modern refrigerator, but it can help keep cool items at hand, and help you become self-sufficient if you don’t have or don’t want electricity in your home.