Keeping food cool
I’m writing from VSO in South Sudan where it’s a snug 40+ degrees for much of the year. We’ll be placing our volunteers in reasonably remote areas and they’re keen to find a way to keep their food cool so it isn’t destroyed so quickly. They mostly want to keep fresh things such as tomatoes, lettuce, green beans etc. I’ve tried one suggestion already: This was a large clay pot with a smaller clay pot inside. The gap between the two pots was filled with sand and water, and the top covered with a wet cloth. I placed this in a well ventilated room. Unfortunately the inner clay pot simply filled slowly with water, making the food rot quicker, and failed to be any cooler than the room temperature. Do you have any other ideas? Alice
I've spent some time in South Sudan lately and it is hot, with daytime temperatures of 40 -50 C pretty well all the time. Given the predictable high temperatures, I would not bother with evaporation methods especially when sunlight is plentiful.
My advice would be to go for a 12 volt fridge (as used in caravans and boats) a solar panel and a battery for night time. The battery should be large enough to provide power for all the hours the sun does not shine, while the solar panels should have an output sufficient to both run the fridge and charge the batteries.
To gain some margin it would be useful to over specify the panels and battery. Besides keeping your salad fresh a fridge would also any keep medicines and drinks cool.
A solar power system would also power radios, lights (LEDs) etc. and recharge laptops, mobile phones and sat equipment. Solar systems are pretty common in parts of Africa, (though nothing much is common in more remote parts of South Sudan).
VSO might want to think about providing a standard pack of solar charged battery systems to serve the above needs. Most of it is off the shelf kit these days.
A very old technique I learned camping with my parents (admittedly not in Sudan) is the use of a food safe, generally hung from a tree with really good ventilation through it.
I have used a modification of this both in Afghanistan where we had no refrigeration and high temperature, where food (fruit, veg, etc) is placed in effectively plastic kitchen racks so the food is only one layer deep on each rack, and keep the differing vegetables / fruits separate. You get good air flow through sides and up through the racks and the foodstuffs stay fresh for some time.
We use a variant of this in rural Cambodia with a lightweight cloth over the racks to keep insects off. Some garlic or alliums (spring onions, onions) basil in the racks keeps a lot of bugs away. In our compound in South Sudan we used the similar idea of a makeshift old fashioned food safe (steel fine mesh box, painted white with closing door and latch) hung under a shady branch of a tree with a good breeze flow through it, and again put the fruit / veg in single layers with air flow from sides and bottom. You can enhance this a little by throwing a wet course cloth (air flow through) over the safe and wet the cloth before putting on the safe rather than pouring water into the cloth and safe. Just an idea may be to have two storage boxes. For example onions deteriorate very quickly if damp whereas leaf crops would likely welcome a damp breeze. Chris
http://en.wikipedia.org/wiki/Coolgardie_safe assuming humidity is not too high – if the evaporative air-coolers rather than air conditioners work in the areas concerned, so should this type of fridge. Other ideas https://www.google.com/search?q=keep+food+cool+without+refrigeration Tim
Clay pot style evaporative coolers can work but do have their own difficulties. One of the main ones is that the inner clay pot is porous allowing water to enter the storage area. There have been different approaches to overcoming this issue, from the very simple lining with plastic bags to more permanent solutions such as having a glazed inner pot.
The main thing is to have a non-porous inner pot so it doesn't necessarily need to be made from clay.
Other considerations would be to improve the air flow over the storage pot which suggests a shaded outdoor location and the tests in Sudan also suggested that placing in the pot onto a metal support to allow air to pass underneath would also benefit in the cooling process.
However, if the clay pot design does is not suitable evaporative coolers can be made with different materials and can be made larger. There is some information on the subject at... https://practicalaction.org/crop-storage-and-preservation-answers
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