Nodepage

Zeer pot fridge

How a clay pot refrigerator can help beat hunger

In hot climates, food doesn’t stay fresh for long. Tomatoes go off in just two days. After four days carrots and okra are rotten. With no means of preserving their crops, poverty stricken families have been battling hunger and even famine.

One ingenious solution is the zeer pot. Using this simple technology, the same vegetable can last for up to 20 days. This all natural refrigerator offers families, who already succeed in food production, their right to food preservation and really can help to improve their everyday lives; for now and for the future.

A simple technology that brings fresh hope

The zeer pot is a simple fridge made of local materials. It consists of one earthenware pot set inside another, with a layer of wet sand in between. As the moisture evaporates it cools the inner pot, keeping up to 12kg of fruit and vegetables fresher for longer.

Making a zeer pot fridge

1 First, bowl-shaped moulds are created from mud and water – and left to dry in the sun. Clay is then pressed onto the moulds to form the desired size of pot. Clay rims and bases are added and the moulds are removed. The pots are left to dry in the sun.

 

2 Once the pots have been fired in a pit of sticks, the zeer pot is ready to assemble. A smaller pot is placed inside a larger one, and the space in between filled with sand.

3 The whole structure is then placed on a large iron stand. This allows the air to flow underneath and aid the cooling process.

 

4 Twice a day, water is added to the sand between the pots so that it remains moist. The entire assembly is left in a dry, ventilated place.

5 Fruit, vegetables and sorghum – a type of cereal prone to fungal infestation if not preserved – are then placed in the smaller pot, which is covered with a damp cloth.

 

6 In the heat, the water contained in the sand evaporates towards the outer surface of the larger pot. This evaporation brings about a drop in temperature of several degrees, cooling the inner pot and extending the shelf life of the perishable food inside.

 

In the hot weather of Sudan, Hawa Abbas used to lose half of her tomato, okra and carrot crop.

Her world changed when she began working with Practical Action. As she herself says, “After many years of struggle, Practical Action came and showed us how to make pottery refrigerators. They are made in two different sized pots. The smaller is put inside the bigger one and in between we put sand and wet it with water and cover it.”

“They keep our vegetables fresh for 3-4 weeks, depending on the type of crop. They are very good in a hot climate such as ours where fruit and vegetables get spoiled in one day.”

It is clear to Hawa Abbas how important this has been to her family. “Since I learned how to make zeer pots our life has been so much better.”

Just £30 could buy 3 zeer pots and help improve people's lives for the future. If you are able to, please buy a Practical Present on behalf of your loved one or make a donation to Practical Action's work today. You really can make a difference.

Alternatively, please share this page with you Facebook friends and Twitter followers. Thank you.

Make a donation

Help us with a one time, or regular donation:

 

You can download further information on cold storage and preservation from Practical Answers, the technical information service of Practical Action, or you can ask a technical enquiry to the Practical Action staff via the online form.

Evaporative Cooling

Keeping produce fresh with refrigeration methods that require no external power.

Evaporative Cooling - The Clay Refrigerator

This document provides some guidelines on making a ceramic or clay pot in pot evaporative cooler.

Evaporative Cooling - The Ceramic Refrigerator

The ceramic refrigerator uses evaporative cooling to keep food fresh without a power source.

Cold Storage of Fruit and Vegetables

This Technical Brief gives an outline of the storage requirements of different crops, and looks at the construction and operation of cold stores.

Refrigeration in Developing Countries

In vast areas of developing countries that are without reliable electricity supply alternative methods for refrigeration are needed.

Comments

1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 Most Recent
  • Reply

    MAMNOON KAZMIE said:

    said:
    THIS IS WONDERFUL IDEA. I MUST INTRODUCE THE IDEA TO THE POOR ALL AROUND US. WHAT BOON TO THEM. CAN YOU PLEASE GIVE ME THE EXACT SPACE BETWEEN THE TWO POTS. I AM OVER 78 AND WISH TO INTRODUCE SOLAR COOKERS. AND WORKING TO FIND EASY WORKABLE DESIGN FOR THE ILLETERATE WOMEN FOLK AND WOULD WELCWLCOME SUGGESTIONS. MY WORK IS ENTIRELY VOLUNTARY,WITH NO INCOME IDEA.
    on 16/4/11
  • Reply

    Daniel said:

    said:
    The space between the two pots is 50mm on either side. Moisture from a layer of wet sand is created from evaporation which in turn cools the inner pot, keeping up to 12kg of fruit and vegetables fresher for longer.
    on 20/4/11
    • Reply

      stalker said:

      said:
      why does that matter? it's helping a lot of people isn't it?
      on 27/5/14
      • Reply

        lol said:

        said:
        what? they were pointing out that the dimensions were important and you're asking why that matters? it matters because that's how it works.
        4 weeks, 1 day ago
  • Reply

    Shahid Zia said:

    said:
    Do we need another earthen cover to put over the two pots fridge. Does it help to keep it in dry and dark place???
    on 26/4/11
  • Reply

    Neil said:

    said:
    The pots should be covered with a ceramic lid or cloth. They should be kept in a well-ventilated area but out of direct sunlight. The pots worked best when they were stood on a metal frame that allowed air to circulate under them as well as around the sides.
    on 4/5/11
  • Reply

    tony benson www.h2ototo.org said:

    said:
    neil i think we met last year when i visited have given small donation do you have any differential temperature records i would love to find a way of developing this further. i am hoping to visit kenya soon on a piece of land i jointly own we could try this out in the next couple of years .. Has the pot got to be any specific quality of clay or can you use any other materials a recipe for the clay would be great if there are any potters out there. Why sand why not just water surrounding the inner pot In a dry environment such as sudan water is scarce any alternatives ??? is there a sand specification ???.. in civil engineering we have a laboratory analysis which shows sand grading using numerous sieves of different sieves showing th best range of sizes of aggregate for concretes if the outer pot is in an insulation jacket does that hinder or help ??? the cover to the vegetables could be sealed or not ???? i thought of forming a simple vacuum seal to preserve veg longer .??? anyone thought of a simple ice maker in the desert possible ???? ps iam looking at rammed earth in more detail are you interested i my findings or have you all the info you need
    on 6/5/11
  • Reply

    Neil said:

    said:
    Tony, Any porous material can be used so as long as the clay allows water to pass through then it should be useable. Other porous materials that are used include clay fired bricks and charcoal contained in a wire mesh. Although water is scare in Sudan and many other places it is more widely available than any other fluid that might work in an evaporative cooler. I think the sand helps slow the whole process down so that not too much water seeps through to the outside. However, Practical Action has not done trials on the grade of sand, the materials used are the ones that are most widely available. The ceramic coolers that Practical Action has used do not have a sealed lid as the inner ceramic pot is not air tight. If you were using a different inner container then you might benefit from an air tight lid. Practical Action has not done any experiments in this area. I’m not sure who has been involved in ice making, there are a few organisations that have worked on refrigeration for developing countries; Warwick Energy Research based at the University of Warwick, UK has been involved in refrigeration for developing countries and has interest with sorption and heat pumps. GrAT - Center for Appropriate Technology at the University of Technology in Vienna has developed a design of refrigerator based on the Ammonia-Water-absorption system called a SolarFrost. We are always interested in additional research into subjects such as the evaporative cooler and rammed earth so would welcome any inputs you may have.
    on 9/5/11
  • Reply

    Edeltraud Baker said:

    said:
    This is great introduction to the wider community. I remember similar systems from Australia. Info from Wikipedia: Principles of operationThe Coolgardie Safe was made of wire mesh, hessian, a wooden frame and had a galvanised iron tray on top. The galvanised iron tray was filled with water. The hessian bag was hung over the side with one of the ends in the tray to soak up the water. Gradually the hessian bag would get wet. When a breeze came it would go through the wet bag and evaporate the water. This would cool the air and in turn cool the food stored in the safe. This cooling is due to the water in the hessian needing energy to change state and evaporate. This energy is taken from the interior of the safe (metal mesh), thus making the interior cooler. The Coolgardie Safe is a low-tech refrigeration unit which uses the heat transfer which occurs during evaporation of water. It was named after the place where it was invented — the small mining town of Coolgardie, Western Australia, near Kalgoorlie-Boulder. It was usually placed on a veranda where there was a breeze. The Coolgardie safe was a common household item in Australia up to the mid-twentieth century. Safes could be purchased ready-made or fairly easily constructed at home. Some of the metal panel safes are very highly decorated, showing the creativity of their makers.
    on 7/7/11
  • Reply

    swapna said:

    said:
    you doing wonderful job....great practical action.
    on 5/8/11

Post a Comment