7 ms·
Yakhchal: Ancient Refrigerators (2009)
- mirimir 8y agoVery cool! ;) It's amazing what's possible with evaporative cooling in dry climates. If you have enough water, anyway.
- SwellJoe 8y agoThis article nowhere mentions how they actually work. The article has that "ancient mystery" vibe about it that I find so annoying about pop archaeology. Googling it reveals they use evaporative cooling, which has also been used at many places and times in history, probably independently discovered, which makes it more interesting to me than glossing over how it works. In short, the WikiPedia article about yakhchals is much more satisfying: https://en.wikipedia.org/wiki/Yakhch%C4%81l https://en.wikipedia.org/wiki/Yakhch%C4%81l
- DmenshunlAnlsis 8y agoFor a very well written and detailed description of the principle of evaporative cooling, you can’t beat Feynman. Section 1-3 http://www.feynmanlectures.caltech.edu/I_01.html http://www.feynmanlectures.caltech.edu/I_01.html
- Waterluvian 8y agoWhile he may very well be both, I will take an average scientist/engineer with a talent for communication over the inverse any day.
- Bromskloss 8y agoThen I can have the opposite case all to myself. Excellent! :-)
- kumarvvr 8y agoThank you. Came to comments to find this out. Evaporative cooling is a very powerful technique, but does not work quite well at small scales.
- mirimir 8y agoSure it does. http://mdpub.com/swampcooler/index.html http://mdpub.com/swampcooler/index.html https://www.etsy.com/listing/115395443/swamp-cooler-vintage-window-ac https://www.etsy.com/listing/115395443/swamp-cooler-vintage-... https://www.amazon.com/s/ref=nb_sb_noss/144-3354102-8246507?url=search-alias%3Daps&field-keywords=swamp+cooler https://www.amazon.com/s/ref=nb_sb_noss/144-3354102-8246507?...
- aekotra 8y agoIt does. https://en.wikipedia.org/wiki/Zeer_pot https://en.wikipedia.org/wiki/Zeer_pot
- kumarvvr 8y agoYes, but with this method, items can be kept at 4.5 Deg Celcius, they cannot hold ice.
- bmelton 8y agoAgreed. Similarly, when I learned of the Indian technique of stepwall evaporative cooling, I was shocked that something so misleadingly simple could have been derived so long ago. https://www.treehugger.com/green-architecture/architect-uses-ancient-techniques-cool-modern-building-india.html https://www.treehugger.com/green-architecture/architect-uses... But, of course people back then weren't any less intelligent, they simply didn't have as much knowledge, probably due to the inefficiency of transmitting knowledge from one generation to another without the use of digital technologies. If anyone is at all interested in ancient (or even just modestly old) cooling techniques, 99 Percent Invisible had a particularly great episode in "Thermal Delight" https://99percentinvisible.org/episode/thermal-delight/ https://99percentinvisible.org/episode/thermal-delight/
- lostlogin 8y ago> inefficiency of transmitting knowledge from one generation to another without the use of digital technologies. Digital technologies haven’t transmitted information between very many generations at all. I don’t think this was the problem.
- WalterBright 8y agoLack of writing was the problem (and paper). The most effective innovation was the printing press - what followed was an explosion of technological progress.
- singularity2001 8y agoprinting press was an improvement, not the invention of information transfer. They were doing just fine with papyrus(paper), leather(letters), tablets, and bark
- cornholio 8y agoThe movable type and printing press combination was introduced by Gutenberg in 1455 and in a single generation spread to hundreds of European cities. By 1500, there were 20 million printed books in Europe for a population of 70 million, mostly illiterate. It was a cultural revolution, in half a century the price of books dropped by an order or two of magnitude. They were transformed from a luxury item only the wealthiest could afford to something any middle class, literate citizen could own.
- duxup 8y ago>annoying about pop archaeology "HOW COULD THEY POSSIBLY HAVE MOVED THIS!?!?!" Many paragraphs or commercials later: "Ok they just put it on top of some logs and rolled it..."
- ryaneager 8y agoMost of the article is pulled word for word from the Wiki you linked.
- zabuni 8y agoEvaporative cooling plus the fact it freezes at night, and they have a system for transferring melted run off to the outside to refreeze. Being originally from a hot, HUMID climate, I find these articles so exasperating. It can get to 85 degrees at night where I was born. So thanks, thanks for the mystic knowledge of the ancients, but it's central and a fridgedair for me. Half the articles are trying to stop people from using cooling compressors, and discuss the limitations in passing.
- linuskendall 8y agoFrom building a mostly mud building in a hot humid climate, it seems that the best you can usually do is "not less comfortable than outside". Basically a large reflective (say straw) roof/shade without walls is the ideal dwelling type, open to prevailing south breezes. Humidity can be regulated a bit using appropriate partitions, but nothing too much as far as I have found. In the end as long as there is enough of a breeze conditions can be kept "moderately comfortable" without AC for most of the year in our location. Though, it does really ask for there to be a nap in the middle of the day. I feel great jealousy for all the creative solutions that can be used in dry climates, including convective and evaporative!
- zabuni 8y agoSadly, where I lived summers usually brought the mother of all high pressure zones, which meant WHAT BREEZE?!!!! Much of the American south has the hottest, most humid type of the year matched with only the dream of wind. The first time I went to the desert I was amazed at how much you can change the climate without a hermetically enclosed environment. Fans work! Shade works! Blowing air over water works! Ice wrapped in a towel works! You can make 115 feel tolerable with very little electricity or effort. THAT'S CHEATING! I solved it by moving away.
- geofft 8y agoThere's no link I think, but I'm fascinated by the windcatcher: https://en.wikipedia.org/wiki/Windcatcher https://en.wikipedia.org/wiki/Windcatcher The specific trick here appears to be that you connect a qanat (underground canal, which routes water from the water table at a higher elevation to the surface at a lower elevation) to the bottom of the structure, and a wind catcher to the top, with its opening facing away from the prevailing direction of wind. Wind blowing past the tower causes a pressure drop near the opening, which draws in air from the other end of the qanat, which is cooler because it's underground / next to water.
- SwellJoe 8y agoI was recently reading about solar chimneys, which is a somewhat similar idea, but driven by heat from the sun rather than wind: https://en.wikipedia.org/wiki/Solar_chimney https://en.wikipedia.org/wiki/Solar_chimney
- swagasaurus-rex 8y agoThank you, I could not find an intuitive explanation anywhere.
- dmos62 8y agoI'm also fascinated by this. I've read about a similar setup where instead of a windcatcher driving the airflow it's wood being burnt near the top of the air channel. I can't recall who used this though. If anyone has some keywords or links, I would appreciate it.
- HillaryBriss 8y agoThis semi-related TED talk also describes Yakhchal and describes a different, local technique of ice production (as opposed to faraway mountains): "How we can turn the cold of outer space into a renewable resource" https://www.youtube.com/watch?v=7a5NyUITbyk https://www.youtube.com/watch?v=7a5NyUITbyk
- mncharity 8y agoThanks! I've been playing with science education content around temperature. 'The universe was once as bright hot as the Sun, but it's been expanding, and is now dark cold. So very cold. The Sun is still bright hot. So very hot. In between, the Earth spins, mixing too hot and too cold. The atmosphere shades us from the hot Sun, and insulates us from the dark cold. Ground and water [buffer the night]. If Earth was much further from the Sun [atmosphere becomes a few feet of snow].' And so on [closer to Sun; non-spinning and Mercury; no atmosphere and lunar temps; more atmosphere and Venus; less buffered desert; etc]. Sort of using a story frame of Sun vs space for teaching temperature in primary school. Raman's work ties in nicely.
- spraak 8y agoAt risk of sounding like a ludite or troll, why aren't these used in modern times? Earth architecture is so efficient and cost effective, it seems.
- deleted 8y ago[deleted]
- saeranv 8y agoWell evaporative cooling, and ground-source energy similar to this does get used in modern architecture. Cooling towers are used to evaporatively cool waste heat from the circulating water in HVAC systems. Thermal labryinths, or earth ducts directly transfer heat to and from the earth, ground source heat pumps do as well through refrigerant loops.
- zabuni 8y agoThey work much better in dry climates that cool down massively at night, and require that digging that far into the ground doesn't make you hit the water table.
- eesmith 8y agoI read an article on this topic about a month ago, but I can't find it now. In short, cheap energy in the post-war US meant that mechanical heating and cooling were affordable. Builders moved away from a vernacular architecture style, which had adapted to the local environment, to a more standardized style that was cheaper to make. While it didn't cover this detail, I think another aspect was that many people decided to move to other parts of the country, and wanted the architecture of where they came from. For example, people from the NE who moved to the desert SW and wanted a Cape Cod bungalow-style house. The vernacular architecture in the SW is for thick adobe walls and small windows. The walls are thick enough that it takes 12 hours for the heat of the day to reach the interior, and help keep it warm during the cold nights. While it's a better fit to the local weather, it's also more expensive to build than a stick-built home + insulation + A/C and heating systems. (Traditional adobe can be built using local mud, but that needs yearly maintenance, because the rains will wash it away.)
- benbreen 8y agoGot to see a bunch of these when I visited Yazd last summer (which in general is just an amazing city, seems straight out of the Arabian Nights). The fun you realize when you’re there is that they’re just one part of a massive infrastructure of ancient technology that also includes the qanat system and the amazingly beautiful wind towers. One theory for the origin of windmills is that they were invented in Sassanid era Persia as well. Really impressive stuff.
- geff82 8y agoThey also had climatized buildings, the „badgir“s.
- sadasivpet 8y agoThis is available in India: https://mitticool.com/product-category/earthern-refrigerator/ https://mitticool.com/product-category/earthern-refrigerator...
- ychn432 8y agoRepost from 2012 :) https://news.ycombinator.com/from?site=eartharchitecture.org https://news.ycombinator.com/from?site=eartharchitecture.org
- singularity2001 8y agoEver since I learned that Persian is related to English (with near identical words for mother,father,daughter,brother…) I enjoy thinking of direct word-correspondences (similar to most English-German pairs): yakh chāl ~ ice hollow / Eis Kuhle/Halde <> hall ~ Höhle yakh meaning "ice" chāl meaning "pit" chāl <> cool@Kuhle
- dyukqu 8y agohttps://news.ycombinator.com/item?id=11719441 https://news.ycombinator.com/item?id=11719441 - Here is a good HN read/thread from two years back about Qanats. Yakhchals was mentioned there.
- walrus01 8y agoIn Dari any normal electrical household fridge is also called a Yakhchal.