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< prev - next > Crop processing Crop storage and preservation KnO 100221_Evaporative Cooling in India (Printable PDF)
This case study highlights the work of Karthik Raman in implementing a technology that
enables the rural and urban poor to preserve produce for longer periods of time. Widely
referred to as the pot-in-pot or zeer, it came to be known as the small fridge or rural fridge in
the local community.
Karthik Raman worked with The Women’s Organisation for Rural Literacy and Development
Society (WORLD) through Indicorps, January 2007. WORLD Society is a non-governmental
organisation (NGO) that focuses on the development issues related to local women. Pot-in-pot
was promoted in the remote villages of the Naickaneri Hills in Vellore District of Tamil Nadu.
As times have changed, the traditional Naickaneri diet has steadily deteriorated for various
reasons. When asked, many villagers felt they were healthier before the drastic changes in
dietary pattern. Many fruits and vegetables are sold by the villagers in the town of Ambur.
Ambur is also where most vegetables are acquired during the dry season. As many cannot
make this trip more than once a week, they are left with no choice but to go without the vital
nutrients in fruits and vegetables for four or five days per week for as many as eight months of
the year.
Three potential solutions for the food preservation issue facing those of the Naickaneri Hills
were considered before opting for the pot-in-pot solution: electric refrigeration, zero energy
cool chambers, and the Pot-in-Pot.
Electric refrigerators
In the Naickaneri community, a fridge is not an ideal solution, as people were not be able to
make the upfront investment in one. Also, many homes did not have the space or even the
access to electricity. Interruptions in access to electricity that last longer than a day occur on
a monthly basis, which also makes this solution impractical for the local population.
Zero energy cool chambers
A zero energy cool chamber is an evaporative cooling system used to preserve fruit and
vegetables using a double brick walled structure. The gap between the two brick walls is filled
with river or lake sand. The sand is saturated with water.
Water must be poured over the sand to ensure that it remains moist. As the water evaporates,
it removes the heat from within the chamber through the process of evaporative cooling.
The advantages of the cool chamber are:
It is relatively inexpensive.
It can be made from locally available materials.
Its size can be fitted to the household need.
It can be easily made and maintained.
The drawbacks are:
Space is required outside the home for it. Many homes are built close together and
this space immediately outside the home would be difficult to find.
Even at the smallest size, it is probably too large for one family's needs.
Needs to be watered daily.
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