The simplest refrigerator — please come to India

Using some of the more basic principles of physics, a grassroots inventor in Nigeria named Mohammed Bah Abba developed a way to refrigerate items simply by using two different sized clay pots. Malapati Sekhar on the Rural Development of India blog explains how this invention, called the Zeer, works:

The pot-in-pot consists of two earthenware pots of different diameters, one placed inside the other. The space between the two pots is filled with wet sand that is kept constantly moist, thereby keeping both pots damp (slightly wet). Fruit, vegetables and other items such as soft drinks are put in the smaller inner pot, which is covered with a damp cloth. The phenomenon that occurs is based on a simple principle of physics: the water contained in the sand between the two pots evaporates towards the outer surface of the larger pot where the drier outside air is circulating. By virtue of the laws of thermodynamics, the evaporation process automatically causes a drop in temperature of several degrees, cooling the inner container, destroying harmful micro-organisms and preserving the perishable foods inside.

Sekhar continues on to highlight how such a simple innovation like this could have a significant impact on farmers’ current behaviors, as it would enable them to preserve their produce long enough to sell at urban markets where prices are much more amenable to them. Utilizing this simple refrigeration mechanism would mean that such food could be stored and sold in areas with the greatest demand.


8 Responses

  1. Interesting post. I’ve had a little experience working with pot in pots through the Indicorps Fellowship. It’s a great idea for ag and has also been used to enable villagers to consume nutritious foods on a regular basis. There’s also been interest expressed in marketing these towards vegetables vendors in urban areas to maximize the amount of time they can sell their produce.

    The zero energy cool chamber is a larger alternative for fresh produce preservation in rural areas. This uses bricks to build a larger area that can be cooled utilizing the same scientific principles. There are agriculture colleges and some NGOs who have worked on this for agricultural development.

  2. The pot-in-pot is already in India and was developed independently of Sekhar’s. In particular, a potter in Ramapir-no-tekro (Gujarat’s largest slum), makes many innovative products as part of his craft, including the low-tech refrigerator.

    Apparently adept at pottery, he’s a failure at marketing and frustrated that nobody is interested in buying his wares. In fact, all products and services at the BOP need to first educate their target markets on why what they sell is needed in the first place, and this is exactly where 99.9% of efforts fail.

    In the absence of that marketing effort, low-income slum dwellers seems more interested in saving up for a TV-advertised small electric fridge instead of taking advantage of a local inexpensive alternative with zero marketing flash and even less ‘status cachet’.

    For an experiment is BOP marketing, see:

  3. As a small boy over fifty years ago, I remember my father putting a tall aluminium pot containing a sweet milk product (baasundi) inside our home drinking water pot made of mud (called madkaa). Ice was rare and often unhealthy.

    We used to drink water from this ‘madkaa’ since it used to be much cooler than ambient temperature and this was used to chill the food in the aluminium pot rather quickly.

    Use of ‘madkaa’ for cool water is very popular all over India and food can be easily chilled in it. This eliminates the inside mud pot and gets quick results. A small family can use larger ‘madkaa’ and chill veggies, fruits, cooked food and extend their shelf life.

    Some 170 million households do not have a chller or a fridge and all could immediately benifit from the ‘metal pot in a madkaa’ concept. Farmers need to use thick walled mud huts with double layered sloping roofs of wet staw mats as ‘chilled rooms’ to store the farm produce for market day.

    The issue of promoting such ‘green concepts’ remains. This is traditional knowledge which is gradually being forgotten due to the loud multi channel shouts on the TV. However, since simple basic desires are not being met even sixty years after political freedom and shortage of electric energy for all the 220 million households in India is a dream for another ten years, NGOs and ‘activists’ need to promote the traditional knowledge to bring relief to the ignorant masses.

  4. Use of mud pots, matka/ kooja is nothing new. It has been used from time immemorial in all societies and in India it was the only way to have cool water not only in homes but while travelling in the endless train journeys from one end of India to the other.
    We tend to have short memories and suffer from acute “modernitis” by which we banish from our collective minds all traditional, simple, inexpensive and eco friendly solutions to make daily life easy, opting instead for the flashy, expensive and harmful solutions that the so called advanced technology enthusiasts would force on us.

    A broken matka disintegrated into clay and could be recycled without any problem. A broken fridge is an object containinf toxic gases and toxis parts that cannot be ever completely recylcled and requires precious, water, funds and special workshops to dispose of.

    I see that someone has written of building. The traditional architecture of India is slowly dying away.
    The government does not fund research work to improve and adapt these solutions, neither do we have a Bill Gates with philanthropic intents in India. A pity

  5. Hi.

    Certain plans are coming through me, a 37 yr old serving officer of the Indian Army originally from a village in Madhubani district of North Bihar in India; though born and brought up in Lonavla in Pune district of Maharashtra state in India. We (My family) still retain contact with our relatives, culture and property in North Bihar.

    Elaborate plans covering all conceivable possibilities concerning this project/ enterprise have evolved through me over a period of SEVEN years; ever since I came in contact with HH Sri Sri Ravi Shankar (‘Art of Living’). Broad details of the plans are as under:

    • The PRIVATE enterprise would be carried out in North Bihar wherein the villagers of North Bihar would be facilitated to raise their own (legally proper) Food Processing Units (FPUs).
    • The enterprise would comprise of a number of ‘Food Parks’ with the HQ being located in a city in a different state in India.
    • The ‘Food Parks’ would provide Packaging, Storage and Marketing facilities (over Internet) to the FPUs for their products for decided Profit percentages.

    The funds for the ‘Food Parks’ so raised are planned to be procured from grants, donations and contributions from individuals, Corporations and Foundations (Indian, Non-Resident Indian and Foreign) as well as from international development agencies like the World Bank, IMF, UN, etc; after the effects of the enterprise start becoming physically visible.

    This project is (ideally) planned to start by operating the first FPU in Madhubani district of North Bihar in India – over three yrs – by 13 May 2010 till 13 May 2013; on funds of minimum $ 1 Million (Rs 5 Crore). 13 May is the date of birth of HH Sri Sri Ravi Shankar. After successful (profit – making) operations of the enterprise; the first ‘Food Park’ of the enterprise would be raised in Madhubani on donations, grants or even Venture Capital on funds of minimum $ 50 Million (Rs 250 Crore)


    What should be the ideal process for procuring the necessary funds by me; an INDIVIDUAL? How and from where could I find some party willing to take this risk on funding these audacious plans? Kindly send me your advice/suggestion at

  6. i live in saini

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