I was thinking about “evaporative cooling” as I got out of the shower this morning and shivered.
In summer’s heat it’s nice how the evaporation of water on your skin cools you down, but in winter, the process is not so welcome.
Still, the principle is something that innovators in hot climates think about a lot, applying it to keeping produce cool so it lasts longer.
Stephanie Buglione, at Nourishing the Planet, has a story on this concept. She focuses on a nonprofit group called Practical Action and how it is using something called zeer pots to reduce food waste.
She explains, “Practical Action, a nongovernmental organization that works with farmers in Southern Africa, Latin America, and South Asia, encourages the use of earthenware refrigerators called zeer pots to help prevent post-harvest food waste. The pot-in-pot refrigerator design keeps fruits and vegetables cool by harnessing the principle of evaporative cooling. These pots can extend the shelf life of harvested crops by up to 20 days by reducing storage temperature.
“The design consists of a large outer pot and a smaller inner pot, both made from locally available clay. Wet sand is added between the two pots and is kept moist. Evaporation of the liquid in the sand draws heat out of the inner pot, in which food can be stored. …
“Zeer pots can provide flexibility for farmers by enabling them to store crops and sell in response to market demand, which can translate into greater income. Extended shelf life also translates into longer-term food sources for farmers and their families. Ultimately, this inexpensive and low-tech system can help farmers and low-income households save food and prevent waste.” More.
Sometimes the best technology is the simplest.
Photo: Noor Khamis/Reuters
Nairobi, Kenya. Many Africans are challenged to keep their fruits and vegetables fresh if they lack electricity for refrigeration. Zeer pots are a low-tech solution that uses the principle of evaporative cooling.
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