No Refrigeration??....No Problem!! Keeping it Cool - Clay Pot Refrigeration

[InDy]

http://www.brinq.com/workshop/archiv...refrigeration/





Keeping it Cool - Clay Pot Refrigeration

This is a relatively old story but a great one. In 2000 Mohammed Bah Abba was awarded the Rolex Award for Enterprise for his innovative Pot-in-Pot system to provide affordable, electricity free, refrigeration in arid Nigeria. Mohammed took an old local understanding of the cooling properties of evaporating water, combined it with the ancient tradition of making clay pots, and turned into a useful, world-changing innovation: a "desert refrigerator" that helps reduce food spoilage and increases income by increasing the shelf-life of farmers' produce for sale.

"Eggplants, for example, stayed fresh for 27 days instead of three, and tomatoes and peppers lasted for three weeks or more. African spinach, which usually spoils after a day, remained edible after 12 days in the Pot-in-Pot storage." [source]

The Pot-In-Pot system consists of two earthenware terracotta pots of different diameters, one placed inside the other. The space between the two pots is packed with sand, the sand is kept wet by pouring water into the sand about twice a day. Produce is placed within the inner pot and then covered with a damp cloth, and the system is left in a dry ventilated area. As the water in the sand evaporates throughout the day, the law of thermodynamics ensures the temperature in the inner pot drops. Our bodies use the same technique to keep us cool.

How well does it cool? Well, one quantative study was performed in Ramona, CA by student Garret Rueda in his 2003 entry to the state Science Fair. Rueda found that average daily temperature drop inside the system was 14 C (23.5 F), aka keeping produce at 15 C (59 F) while the outside temperature is 28 C (82.4 F).


Finally, the Rolex Awards Committee makes a great point about ideas vs. innovation in their article about the Pot-in-Pot award: "Good ideas are indeed rare, but good ideas that actually become good projects and bring lasting benefits are even rarer still," In other words, an innovation is an idea that is brought to life and changes people's lives.

[AZ Prepper]

Those clay pot refrigeration systems are pretty cool! I need to make me one to try out in the hot, dry Arizona summer.

[InDy]

http://ditchyourfridge.blogspot.com/...tching-in.html

Kim from Adelaide, Australia has shared this great post with us on her life without a fridge and some alternative cooking ideas! I'm so inspired that living in the heat all year round can be done so well. This summer I am trying this too.

You can make your own refrigerator for free, from stuff that you find in the rubbish, and it doesn’t need any electricity to run, just water. And it really works! Here’s how:

All you need is two clay pots, some sand, and a way to plug the hole in the bottom of the pot.

Get two terracotta pots, one needs to fit inside the other with about 1cm gap between. They could be the same size with one slightly raised. They need to be unglazed, unsealed terracotta, as the cooling happens by evaporation through the porous clay. Pots can sometimes be found in hard rubbish, or by asking around. If you’re really keen you could get hold of some clay and make them yourself. Or if you’re not, try secondhand from a garage sale, flea market, salvage yard or tip shop. They’re about $10 each from hardware stores. Imported from Italy.

Next step: plug the holes in the bottom of the pots, so that water doesn’t drain out. I did this with the lid of a PET bottle and sealed the edges with waterproof silicon sealant, but I’m sure there are other ways that are equally effective. I tried to go low-tech and use clay, but it got soggy and fell apart.
Line the inside of the larger pot with sand, and place the smaller one inside.

Placing the pot in a tray is a good idea, as on hot days the cool water condenses on the outside of the pot and runs down the side. This water is great to cool yourself in hot weather.

Top up the water in the sand layer every day so it stays damp, and cover the top with a towel. Even when it’s over 40 degrees outside, the inside of the zeer pot is 15 degrees, so food keeps a lot longer than it would without refrigeration.

One catch: the evaporation process needs a dry climate to work effectively. It wouldn’t do so well in a humid place.

Some more refrigeration tips:

Lots of things that are often kept in a refrigerator really don’t need to be. Sauces, jams, miso, eggs and fruit keep perfectly well out of a refrigerator.

Many vegetables keep better in a dish of water. This way they continue to be alive so are much more nutritious. Celery, broccoli, leafy greens and beetroot keep really well this way. Tomatoes, cucumber, zucchini are generally fine out of the refrigerator.

Of course all these things are much tastier and higher in nutrients if they are eaten directly from the plant. I read somewhere that leafy greens lose 90% of their nutritional value within hours of being picked. A great reason to eat weeds and grow your own food!

[InDy]

I just posted a link to a PDF in the download section (under Preparedness and Survival) that explains how to make these Zeer Pots from the ground up starting out with pretty much nothing else but mud and water (and a few other things found in the natural environment). Check it out!! Here is the link to the download:

http://www.ldspreppers.com/local_lin...&catid=2&id=90