A Yakhchal was an ancient type of ice house that functioned using evaporative cooling. Above ground, the structure had a domed shape, but had an underground. This was often used to store ice, but sometimes was used to store food as well. The underground space, combined with the thick, heat-resistant material, insulated the storage space year round. The structures were mainly built and used in ancient Persia, and many that were built hundreds of years ago are still standing.
How they worked
A yakhchal takes advantage of the low humidity in desert climates which promotes the evaporation of water (making evaporative cooling more effective) and promotes rapid cooling once the sun sets (water vapor inhibits radiative cooling in less arid climates). In some deserts, temperatures drop below freezing at night. Water was often channeled from a qanat (Iranian water delivery system) (possibly a topic for another megathread) to the yakhchal, where it freezes when the temperature is low enough. A wall is usually built in an east–west direction near the yakhchāl. Incoming water is channeled along the north side of the wall so that radiative cooling in the shadow of the wall cools the water before it enters the yakhchāl. Ice was also sometimes brought in from nearby mountains and stored in the yakhchāl.
The building allows cold air to pour in from entries at the base of the structure and descend to the lowest part of the yakhchāl, large underground spaces up to 5,000 m3 (180,000 cu ft) in volume. At the same time, the tall conical shape of the building guides any remaining heat upward and outside through openings at the very top of the building, and through this active process the air inside the yakhchāl remains cooler than the outside.
The heat-resistant material that allowed the yakhchal to function was known as sarooj. This was composed of sand, clay, egg whites, lime, goat hair, and ash in specific proportions. Sadly, this means that sarooj was not :im-vegan:, but I’m sure you can find substitutes for the egg whites. It was, however, very resistant to heat transfer, and it was thought to be impossible for water to travel through it. Sarooj was effective year-round, and could be as much as two meters thick at the base.
The ice stored within was used year-round, especially during hot summer days. Some uses would be preservation of food, to chill treats, or to make faloodeh, a traditional Persian frozen dessert.
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I guess you could say that yakhchals are pretty…cool, huh? :big-cool:
I know, wikipedia is such a trap sometimes! I'll be reading an article, think "Oh, interesting," open a new tab, and before I know it I've got like 20 wikipedia tabs open.
Yeah, with an occasional glance at that row of pre-opened tabs on the right, thinking "I have stuff to do, I'll stop soon for sure, there's only like 12 tabs left". Two minutes later there are like 16 tabs now.
I know! I don't know if it's my ADD or wikipedia's sorcery (probably both), but I get stuck there way too often when it's time to go to bed or I have something I actually need to be doing.
I can fully rationalize it cause I'm learning stuff
Right? It's not poor time management skills if I'm learning stuff!
The only time I have to manage is that I have to work sometimes. Sleep is cool but I work late afternoon so I can always make it up on the other end to some extent.
Fuck, now reading about the symptoms I'm low key wondering if I have ADHD. Though if I have, pretty sure my sister and mother do too by the standard of diagnostic I'm reading about.
It's definitely possible. One of my brothers is diagnosed, and I'm pretty sure my mom is undiagnosed and so is one of her brothers. If you have the means, it's worth looking into. Getting a diagnosis and treatment can really change your life.
I teach. Almost the entirety of the students I taught seemed to assume I was on coke or another stimulant while teaching (I wasn't). The number one negative reports was "talks / goes too fast". And the things I'm reading about poor working memory, propensity to substance abuse (I quote, "especially cannabis and alcohol") and depression all ring true.
It really is amazing how many undiagnosed adults there are. The kids who misbehave are the ones who get treatment, it seems. I've heard that's part of the reason why women are more likely to be undiagnosed--we're less likely to misbehave in school as one of our symptoms. I don't know if that applies to you from your pronouns, but I thought I'd mention it, just in case. Even my brother though, nobody ever brought up ADHD when he was a kid because he didn't get in trouble. When he finally got a diagnosis as an adult and got on medication, his whole world changed.
It doesn't, I'm a dude, but thanks for mentioning it. Though reading about it, shouldn't ADHD be helped with stimulants ? I've only ever taken CNS stims recreationally (MDMA, designer drugs close to meth, and coke) and rarely at that - really not my favourite class of drugs; and those didn't make me feel exactly like I got better. I was more social, but mostly I was high. That's making me doubt such an idea. Or maybe recreational dosages are too high ? maybe I'm just basically hyperactive due to my environment, though.
I know that ADHD drugs are stimulants, but I don't know anything about whether self medicating with other stimulants is supposed to work. I've never used any, so I can't make a comparison. I would assume that, like you said, the dosages are different. Anyway, if you have insurance, it's worth investigating!
Better than that, I have universal healthcare. Thanks for your kind answers !
Weird thing is I did this as a pre-internet kid with Encyclopedias. See Also was the hyperlink of it's day.
Me reading the encyclopaedia with a dictionary next toit for the words I dont know
I did too ! I have a vivid memory of looking at the "rocket" article in encarta and understanding how the basic force towards the sky worked. They had an awesome animated gif that explained the idea instantly.
You know, I've never thought of it that way, but I did too. We had an old encyclopedia set my dad got used, and I used to do the same thing. I hate to say it, but we were weird kids!