Harvey, you mentioned seeing an article about clay-jar coolers National Geographic.
I can confirm that they do exist, and that they do work. At the start of my career I was living in the Sahel region of northern Nigeria. We had a scant and irregular electricity supply ... maybe 3-4 hours in the evening, 2-3 times a week if we were lucky. Like everyone else in the town, we kept our drinking water in large unglazed fired-clay jars, situated in a breezy but shady spot at the back of the house. The jars cooled the water by several degrees centigrade ... the breezier, the better. When I moved to Southern Africa, I met old-timers who remembered using the same principle to construct "bush fridges" to store meat they'd shot on hunting trips. Their system involved building a temporary structure with one wall made out of loosely-packed porous material (located on the up-wind side) and the other 3 walls made out of rocks and close-mesh chicken-wire. The up-wind side was kept saturated with water, and the air passing through was cooled sufficiently to delay the onset of decay in the meat. I have no idea what temp-drop they achieved; they used to tell (tall ??) stories about their meat freezing solid (actually, the best stories involved parts of the anatomy freezing solid), but when I got some of my schoolkids to test this for a science project, the best cooling we could achieve was only a few degrees centigrade. What's this got to do with orchids ? Well, unless I've totally misunderstood the science, evaporative-coolers work on the same principle, and are quite commonly used to cool greenhouses in parts of the USA. I also know a man who has built himself a small evap-cooled wall, and is growing high-altitude Phalaenopsis on it. The porous material he is currently using (after trying and discarding several other materials) is the stiff plastic-mesh stuff that you use as a scouring pad for scrubbing pots and pans in the kitchen. He got a whole load of reject pads from the factory that makes them.... all it cost him was the transport. Cheers, Peter O'Byrne in Singapore _______________________________________________ the OrchidGuide Digest (OGD) [email protected] http://orchidguide.com/mailman/listinfo/orchids_orchidguide.com
