Pot-in-pot refrigerator

The pot-in-pot refrigerator or zeer (Arabic: الزير‎) is a algidity accessory which keeps aliment air-conditioned after electricity by application evaporative cooling. A absorptive alien ceramics pot, lined with wet sand, contains an close pot (which can be anesthetized to anticipate assimilation by the liquid) aural which the aliment is placed. The dehydration of the alien aqueous draws calefaction from the close pot.

Although the assumption abaft the accessory has been accepted for centuries, one avant-garde accessory was developed by academician Mohammed Bah Abba for use in avant-garde Nigeria and broadcast by his company, Mobah Rural Horizons.1 The accessory was reinvented by English artist Emily Cummins in 2006, for which she won a Female Innovator of the Year for 2007 from the British Female Inventors and Innovators Network2 as able-bodied as a £12,000 advocacy from NESTA.34

The accessories can be complete with simple apparatus and are benign for areas of the developing apple area electricity is capricious or non-existent.56

History

There is some affirmation that evaporative cooling was acclimated as aboriginal as the Old Kingdom of Egypt, about 2500 B.C. Frescos appearance disciplinarian fanning baptize jars, which would access air breeze about the absorptive jars and aid evaporation, cooling the contents.7 Many ceramics pots were apparent in Indus Valley Civilization about 3000 BC which were apparently acclimated for autumn as able-bodied as cooling baptize agnate to present canicule ghara or matki acclimated in India and Pakistan.8

Despite getting developed in Northern Africa, the technology appears to accept been abandoned with the appearance of avant-garde electrical refrigerators. However in the Indian Subcontinent, ghara, matka and surahi, which are altered types of ceramics baptize pots are acclimated to air-conditioned the water.9 In, Spain the accepted botijos, absorptive adobe containers to accumulate and to air-conditioned water, accept been in use for centuries (and are still almost widespread), alive in the aforementioned way as the pot-in-pot refrigerator, advantaged by the low Mediterranean altitude humidity; locally the cooling aftereffect is accepted as "botijo effect".1011

The address of application evaporative cooling with adobe pots for aliment canning was re-discovered by Mohammed Bah Abba, a Nigerian abecedary from a ancestors of pot-makers, who patented a pot-in-pot refrigerator in 1995 to advice Sudanese families bottle food. Bah Abba was awarded the $75,000 Rolex Award for Enterprise in 2000 and the World Shell Award for Sustainable Development in 2001 for its development.1213

Development and distribution

Mohammed Bah Abba developed his zeer based on his grandmother's adeptness of acceptable pottery. Wanting to use acceptable methods to advice the rural poor of arctic Nigeria,14 he hit aloft the abstraction of refrigerating aliment by agreement it in a pot, again careful the pot with some actual independent in a beyond pot. It took him about two years to advance and analysis the idea, and during this time he experimented with abounding altered types of careful material, including cream from an old mattress. In the end, he begin that wet river beach was the best actual for his cooler. He anesthetized his account assimilate the Intermediate Technology Development Group, who in about-face formed with the University of Al Fashir to run abstracts on the zeer to admeasurement its adeptness to advance food's comestible agreeable and extend its shelf life.15 After tests were concluded, Bah Abba began to deliver zeers.13 He gave abroad the aboriginal 5,000 pots for free, demography the amount from his lecturer's salary. He aswell approved several methods to advance the pots for abundantly benighted villages, and eventually begin that it was a lot of able to almanac a play in which the zeer featured, at which point a publicity aggregation took the video about the villages and projected it assimilate the walls of houses in the black if workers were advancing home from the fields. In this way ample numbers of humans were apparent to the zeer if they angry up for the chargeless entertainment.13

Construction

A zeer is complete by agreement a adobe pot aural a beyond adobe pot with wet beach in amid the pots and a wet bolt on top.[14]
The accessory cools as the baptize evaporates, acceptance aliment stored in the close pot to be kept beginning for abundant best in a hot, dry climate. It have to be placed in a dry, aerial amplitude for the baptize to clear finer appear the outside. Evaporative coolers tend to accomplish ailing or not at all in climates with top ambient humidity, back the baptize is not able to clear able-bodied beneath these conditions.
If there is an closed break band amid the aliment and the absorptive pots, undrinkable baptize such as seawater can be acclimated to drive the cooling process, after communicable the food. This is advantageous in barren locations abreast the ocean area cooler baptize is a bound commodity, and can be able by application a pot that has waterproof coat activated to the close bank area the aliment is stored.
Extended operation is accessible if the pots are able to draw baptize from a accumulator container, such as an astern closed jar, or if the pots are placed in a bank basin of water.

Impact

Pot-in-pot algidity has had assorted absolute impacts on the citizenry that uses them above the simple adeptness to accumulate aliment beginning for best periods of time and abbreviating instances of food-related disease.14

Added profits from aliment sales: As there is no blitz to advertise aliment to abstain spoilage, farmers are able to advertise their aftermath on appeal and can command college prices.

Added opportunities for women: Women can advertise aliment anon from their homes, abbreviating their assurance on their husbands as sole providers. Also, because girls commonly yield aliment to bazaar to sell, and because aliment in the zeer stays beginning continued abundant that they can go to bazaar already a anniversary rather than already a day, there is added time for them to appear school.

Rural application opportunities: Farmers are able to abutment themselves with their added profits at market, slowing the move into cities. Also, the conception of the pots themselves generates job opportunities.

Added diet array because aliment is accessible for best into the year.

A zeer costs about 150 naira (approx. US$1.00 in 2011) to make, and they advertise for 180-200 naira (US$1.20 to US$1.30 in 2011). Bah Abba sells about 30,000 per year.13

Reinvention

In 2006 Emily Cummins apart invented a agnate device.18

The accessory can be fabricated for frequently attainable actual such as cardboard, beach and recycled metal.19 The accessory is composed of two cylinders. The close metal butt is adapted central the alien butt which can be fabricated from whatever abstracts the architect has admission to, including copse or plastic.2021 Space is larboard amid the close and alien alcove to be abounding with amoebic actual which can cover sand, absolute or clay that is again saturated with water. As calefaction from the sun evaporates the water, the close alcove cools abbreviation and advancement the temperature at 43 °F (6 °C).65

Cummins's accessory is acclimated in areas of Africa such as Zambia, Namibia, and South Africa in areas area electricity is generally not readily attainable to advice bottle decaying foods such as meat and dairy products. It is not yet getting acclimated for vaccines.5