Wednesday, March 18, 2009

How About a No-kilowatt Fridge?

It is a well-known fact. I go to the produce stand and lose all self-control. I am like a kid in a candy-store. I buy one - no - two - half a dozen of everything.

I come home flushed with victory (and the 35 C / 95 F degree heat), walk in the door, smack my forehead with an open palm and cry "Doh!"

We have a six cubic foot refrigerator! This is a HUGE step up from the 3.2 cubic feet of the fridge in the Tinpalace, but it's still not much when you've just bought 25 or 30 pounds of fresh produce that needs a cool place to rest until you can get it in your tummy or preserved.

So we were debating. Do we buy another fridge and put it out on the deck? Most people here have an extra fridge and many have both an extra fridge and a freezer. But we're trying to cut down on power consumption, not increase it, and we do fine in the winter, when I manage to stuff everything I buy into the fridge.

Then, while looking at a site for solar ovens (of all places) I ran onto mention of something called the Zeer or pot-in-pot which was developed by teacher Mohammed Bah Abba. Bah Abba realized that he could put the second law of thermodynamics and transpiration to work to keep food cool.

The Zeer pot is made with two unglazed clay pots, one pot smaller than the other. The smaller pot is put inside the bigger pot, and the space in between them is filled with sand. The sand is watered twice a day and a wet towel is put on top of the two pots to keep warm air from entering the interior. As the water in the sand evaporates through the surface of the outer pot, it draws heat away from the inner pot and carries it away.

The inner pot can be filled with water, fresh fruit, vegetables or even meat. In this way, fresh produce can be kept for long periods of time without the need for electricity, or the high embodied energy of a camping cooler. Tomatoes and peppers which usually spoil in two days in Africa's heat will last for up to three weeks, and African spinach, which normally spoils after just a day, remains edible for up to five days. Eggplants will keep for up to 27 days instead of three.

The Zeer will keep water (and other beverages) at about 15 degrees Celsius (59 F) and they say that meat can be kept fresh for long periods, though I wouldn't be putting meat in one. I am very squeamish about meat - I want it kept almost at the freezing point. I guess it's better than uncooled at all though, and might keep meat from spoiling for an extra day. So, once the deck is built I will buy a couple of large clay pots and set up a "Zeer" produce cooler on the deck for all that extra produce I go nuts for in the middle of July.

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