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I live in the HOT desert near Death Valley. I was wondering, if anyone or group has used the idea of Yakhchals (which I have not known about, till now), to keep water cold, or tried to freeze, currently. What a great energy-saving idea Yakhchals are!

The engineering is not clearly explained, especially the part about “evaporative cooling”. It seems more likely that the owner applied straw on the sunny side to protect against solar heating, and cooling was by radiation into the north sky at night. The rest of the structure was merely well insulated. A fairly cool ground temperature was also part of the deal, as the water system was rather elaborate in those areas. If you want to experiment you could try Styrofoam insulation with foil on the sunny side. Any lumber yard carries that material.

The University of Arizona has done quite a bit of research on Down-Draft Evaporative Cooling Towers (similar to the Yakhchals) . They built a demonstration model in Tucson. I just wanted to get a lawn chair and sit in front of it all day.