this post was submitted on 24 Jul 2023

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Mildly Interesting

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Ancient Iran had air conditioning (lemmy.world)

submitted 2 years ago by FlyingSquid@lemmy.world to c/mildlyinteresting@lemmy.world

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[–] Lenins2ndCat@lemmy.world 139 points 2 years ago (9 children)

This isn't just mildly interesting. We should be considering methods of air cooling that do not use any carbon in order to avoid aircon usage becoming a contributor to the climate problem as things get hotter and hotter.

[–] MetaCubed@lemmy.world 97 points 2 years ago* (last edited 2 years ago) (9 children)

I agree with you that we should be exploring alternatives, but aircon is extremely energy efficient for how much thermal energy it moves (reaching 400% efficiency in some cases) . The problem isn't aircon itself, but what is being used to power it (coal/natural gas power plants)

In fact the technology behind aircon can be expanded into a heat pump to both heat and cool, being more efficient than electro-resistive or gas heating. There's even water heaters that will actually cool the area they're in and use the heat they gather from the space to heat the water.

Technology Connections has a great series of videos that go in depth on both heat pumps and aircon.

[–] spongebue@lemmy.world 19 points 2 years ago (1 children)

Yeah, "air conditioning powered by solar/wind/hydro" can feel like it's one big Rube Goldberg machine to make air cool, but the reality is that it comes together to make something that can scale really easily. I can't imagine coming up with a design like what's in OP for an apartment complex or condo building.

Source: just made it up, but also a Technology Connections fan. All that's to say, feel free to correct me with a little data

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[+] argh_another_username@lemmy.ca 90 points 2 years ago* (last edited 2 years ago) (14 children)

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[–] Gangreless@lemmy.world 62 points 2 years ago* (last edited 2 years ago) (15 children)

A modern home ACs can only cool about 20f below the outside temperature. 50c to 35c is 27 degrees so that's pretty damn good for a fancy unpowered swamp cooler

[–] Norgur@kbin.social 56 points 2 years ago (3 children)

Yeah, the thing is the "unpowered" part. Look how much energy an AC chugs to achieve that cooling. This tower uses wind power to do it's thing.

[–] Duder167@lemmy.world 42 points 2 years ago

The AC is also small compared to a literal building with a sewer underneath and doesn't require a windy day. Trade offs

[–] janus2@lemmy.sdf.org 8 points 2 years ago (7 children)

well technically it is powered, just directly by wind and water kinetic energy, probably(?) much more efficiently than if it had been converted to electricity first

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[–] manillaface@kbin.social 24 points 2 years ago (3 children)

What’s your source for this? It routinely gets over 100 here and buildings aren’t 80 degrees inside.

[–] sab@kbin.social 14 points 2 years ago* (last edited 2 years ago) (2 children)

~~We're talking celsius, I hope for your sake it doesn't routinely get to 100 C where you are. :)~~

Edit: The user actually said 20 F, I got confused by the mix of units. "50c to 35c is 27 degrees" didn't make sense to me, but I figured I'd let it slide. No idea what's going on here. :)

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[–] Dark_Arc@lemmy.world 13 points 2 years ago

They're full of it, that's it. Maybe in their house which lacks sufficient insulation. Heat pumps (i.e. air conditioning) are/is extremely efficient at moving heat around, there's not really a practical limit on it, particularly if you go geothermal.

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[–] sci@feddit.nl 22 points 2 years ago (2 children)

pretty sure 50c to 35c is 15 degrees

[–] pfannkuchen_gesicht@lemmy.one 27 points 2 years ago* (last edited 2 years ago) (2 children)

I wonder how he got his number, it makes no sense.

EDIT: oh, he just randomly mixed °C and °F, because why not...

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[–] Duder167@lemmy.world 13 points 2 years ago

50c is 122f, 35c is 95f so he went 50c-35c = 122f-95f = 27f because why the fuck not.

[–] WhiteTiger@lemmy.world 10 points 2 years ago

That's just not true, a modern home can be at 70f or below when its 110f outside. Air comes out at 50-55 even at those outside temps.

[–] monz@pawb.social 10 points 2 years ago (3 children)

What do you mean modern AC can only cool by 20F?

I’m in Florida and it’s routinely 95-98F outside. My AC is set to 65F.

Did you mean 20C? Either way, that’s also false. AC units are limited to their rating and BTU. Many may not cool below 60F, but there’s no delta limit.

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[–] sab@kbin.social 25 points 2 years ago* (last edited 2 years ago) (4 children)

10 degrees is incredible though.

These days in Yazd the average warmest temperature in July is 40 degrees, so if what you're saying is correct they'd be able to cool it down to a liveable 30 degrees even in the warmest part of the day. And at night temperatures still dip to 26, so the indoors temperature probably wouldn't quite reach 40 even without this system. So it might make the difference between 40 degrees outdoors and high 20s indoors, which is fantastic.

Would be interesting to know if average temperatures got up to 40 in the summer around the time they were built as well, or if average temperatures in the region have been rising.

[–] luthis@lemmy.world 14 points 2 years ago

And what wind strength is required to achieve 10C decrease

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[–] Steeve@lemmy.ca 9 points 2 years ago

Oh man, I can't believe ancient physics powered cooking techniques weren't as efficient as the electrically powered cooling that we have today, those idiots

[–] Szymon@lemmy.ca 7 points 2 years ago

Might not be a shivering 16 Celsius inside, but if it's the difference between dead and alive then it's probably good enough.

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[–] hark@lemmy.world 52 points 2 years ago (9 children)

I love passive systems. The more passive the better.

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[+] SpaceCadet@lemmy.world 46 points 2 years ago* (last edited 2 years ago) (6 children)

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[–] Jilanico@lemmy.world 27 points 2 years ago (4 children)

I've read that these wind catchers were used to keep ice frozen in ice pits during summer.

https://en.m.wikipedia.org/wiki/Yakhch%C4%81l

Fun fact: Ancient Persia had ice cream like desserts enjoyed year round.

[–] DarthBueller@lemmy.world 8 points 2 years ago (1 children)

Amazing - I had no idea that anyone was making ice in the desert in BCE times. The wikipedia article seems to indicate that they did a lot of storing of ice in the Yakhchal structures - but it is confusing as to how they made it. It seems like they either gathered the ice from the mountains, or made it in outdoor shaded "ice pools" that were situated next to the Yakhchal. Surely the ice required winter desert temps to form? Otherwise how would the thermal mass of the ground ever get cool enough to allow ice to form, even with the magic of physics? The permanent shading helps, but year round-ice making surely wasn't a thing, was it?

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[–] MeanEYE@lemmy.world 23 points 2 years ago (1 children)

It's called evaporative cooling and it's quite potent since water takes enormous amounts of energy when changing states. It takes around 5x the energy to convert 100°C water into 100°C vapor than it takes to increase temperature of said water from 0 to 100°. This energy has to be taken from somewhere and that is from the environment, dropping the temperature as a result. Problem with these is that the humidity of the air increases. Not much of a problem in desert, quite a bit problem in other places.

Here's a great video explaining science behind evaporative coolers and how it can be modernized. https://www.youtube.com/watch?v=R_g4nT4a28U

Just wind tunnels without water, I agree with you.

[–] jerrimu@lemmy.world 8 points 2 years ago (4 children)

No, it's a swamp cooler, which is still used today in drier climates. This is a desert, so yes the air is not humid, and yes the water is cool because it's underground. Stop being so pedantic.

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[–] yesimprogun@lemmy.world 7 points 2 years ago

I think the areas these were used in were fairly dry so they worked like swamp coolers.

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[–] sci@feddit.nl 28 points 2 years ago* (last edited 2 years ago)

Not really mentioned in the picture but Qanats are basically underground aquaducts, bringing water from nearby mountains to the cities. They can be up to 70km long. We went into one when I visited Iran.

[–] oshaboy@lemmy.world 27 points 2 years ago (4 children)

Not quite an air conditioner, but it seems modernizing it could be a great idea for new constructions to save on power. Maybe as a supplement to Air Conditioners.

[–] BlazeMaster3000@lemmy.world 8 points 2 years ago (1 children)

Not quite an air conditioner, but it seems modernizing it could be a great idea for new constructions to save on power. Maybe as a supplement to Air Conditioners.

It's called "radiant floor cooling/heating" and this has existed for a while.

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[–] ezmack@lemmy.ml 26 points 2 years ago (1 children)

Lotta old Victorian homes and factories from that Era did the same thing (without water obviously just a big tower to catch the wind). More like an attic fan than an AC in those cases, still a pretty clever way to move air without electricity. Always impressed by how clever people were back in the old times

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[–] boonhet@lemm.ee 18 points 2 years ago (7 children)

Ancient Iran had swamp coolers* to be more accurate here.

This works in the desert, but you can't replicate it in a humid climate like you can with AC.

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[–] jerrimu@lemmy.world 16 points 2 years ago (1 children)

Wow, I thought quanat was a made-up word from dune.

[–] Kolanaki@yiffit.net 8 points 2 years ago (1 children)

If "Kwisatz Haderach" is also a real thing that would be weird.

[–] lagomorphlecture@lemmy.world 9 points 2 years ago

It's derived from Hebrew.

[–] halvar@lemm.ee 15 points 2 years ago

I tought this was a meme and have been looking for Saddam Hussein's red sillouette for half a minute.

[–] CWSmith@lemmy.ml 13 points 2 years ago (2 children)

This looks like some other things I have heard of before.

Makes me wonder how many ancient desert cultures designed ways to cool the air in their structures.

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[–] Loui@feddit.de 13 points 2 years ago

I was told that the houses in trinidad, Cuba have a similar cooling effect. Also the round white houses in tunesia have a cooling effect. Any tunesian or Cubans here?

[–] ultimate_question@lemmy.world 10 points 2 years ago

I remember using something similar to that in college but if I recall correctly it was for weed

[–] inototen@lemmy.world 9 points 2 years ago (4 children)

I think that the Eastgate Mall in Zimbabwe makes usage of a similar principle, but their inspiration came from Termite Mounds https://www.youtube.com/watch?v=qP8DSdfoiZw

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[–] paddirn@lemmy.world 8 points 2 years ago (3 children)

I'm always amazed by stuff like this that ancient peoples were able to work out on their own. Like how would they even figure any of this stuff out on their own? Obviously it had to be Aliens. /s

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