6 ms·

This article nowhere mentions how they actually work. The article has that "ancient mystery" vibe about it that I find so annoying about pop archaeology. Googli

This 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 ago
For 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 ago
  While 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 ago
    Then I can have the opposite case all to myself. Excellent! :-)
kumarvvr 8y ago
Thank 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 ago
  Sure 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?...
  - kumarvvr 8y ago
    None of them can keep ice in ice form though.
    - mirimir 8y ago
      True.
- aekotra 8y ago
  It does. https://en.wikipedia.org/wiki/Zeer_pot https://en.wikipedia.org/wiki/Zeer_pot
  - kumarvvr 8y ago
    Yes, but with this method, items can be kept at 4.5 Deg Celcius, they cannot hold ice.
bmelton 8y ago
Agreed. 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 ago
    Lack 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 ago
      printing 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 ago
        The 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 ago
Most of the article is pulled word for word from the Wiki you linked.
zabuni 8y ago
Evaporative 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 ago
  From 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 ago
    Sadly, 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.

DmenshunlAnlsis 8y ago

For 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 ago
While 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 ago
  Then I can have the opposite case all to myself. Excellent! :-)

kumarvvr 8y ago

Thank 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 ago
Sure 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?...
- kumarvvr 8y ago
  None of them can keep ice in ice form though.
  - mirimir 8y ago
    True.
aekotra 8y ago
It does. https://en.wikipedia.org/wiki/Zeer_pot https://en.wikipedia.org/wiki/Zeer_pot
- kumarvvr 8y ago
  Yes, but with this method, items can be kept at 4.5 Deg Celcius, they cannot hold ice.

bmelton 8y ago

Agreed. 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 ago
  Lack 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 ago
    printing 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 ago
      The 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 ago

Most of the article is pulled word for word from the Wiki you linked.

zabuni 8y ago

Evaporative 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 ago
From 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 ago
  Sadly, 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.