Ancient Iran had air conditioning

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.
- 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.
  
  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
  
  400% efficiency is good, but it's not better than the ∞% efficiency you get from something that doesn't require fuel input to begin with. (I'm pretty sure the Technology Connections guy would agree on that point.)
  If nothing else, think of it this way: even if you still want to use air conditioning to make sure you get all the way down to comfortable room temperature or whatever your target is (which a Qanat, although able to achieve a >15°C ΔT, might or might not be able to do reliably), it'll still give you a big head start and greatly reduce the amount of energy needed. It's a lot like using a ground-source heat pump instead of an air-source one. What's not to like‽
  
  Can you explain 400% efficiency?
- This would be a great idea if you want everyone in that building to file humidity complaints every single day. Air conditioners work by using mechanical work (compressor) to exploit evaporation in order to pull heat from one location to another and exhaust it away, in turn cooling the first location (this could be air, water, etc.)
  This system works by using ground temp water as a heatsink to suck heat out of the air passing over it. When it does this, it humidifies the air. In the desert...who cares? In an office building...who cares? Every single worker who is stuck there all day
  If you're saying we need better systems than the AC unit you grew up with, fear not! Many office buildings have been moving away from it (same with other large venues) they use a chilled water system. They use the best of both these systems to get WAY more performance out of way less wattage. You only need a fraction of the cooling power with a chilled water system because the water can absorb much more heat per unit mass than air and can be sized to never run during the day, but only at night when the grid is least in use
  
  AC unit you grew up with
  Lmao grew up with? Most of us have never used AC at all in europe. Here in the UK no homes have AC. The issue is that people are installing it now because of climate change and the result is massively higher energy use.
  
  Obviously, you use the tech in the situations it's appropriate for. If your office building happens to be in Phoenix, AZ, then a qanat might be a pretty good idea!
- https://www.youtube.com/watch?v=5zW9_ztTiw8 Have you seen this? Seems like the next big thing in AC is just around the corner :-)
- I had a crazy thought. What if you used depressurization to cool interiors?
  Not as in depressurize the room and potentially kill the people inside, but in a way similar to soundproofing where you create an airtight gap in your walls, depressurize it to create a partial vacuum and effectively restrict both heat and sound transfer. That way it would be much easier to control internal temperature.
  The only two problems I can see with it is expense (pumping air out of the gaps between your walls could be pricey), and the potential of explosive repressurization if something were to break the wall.
  
  Wall isolation is pretty fine as it is, main weaknesses are windows and thermal bridging.
  We still have the issue that a perfectly isolated house will need to lose the heat created by humans and electric systems, so actual cooling is required.
  
  And how do you get fresh air in? Also the problem of heat transfer is never by gaps in the walls, at least not for buildings in western and central Europe. The problem is heat conduction through the window panes. And that is with isolated windows already. Also it is impossible to get a brick wall air tight. Leave alone you create a great environment for water to leak in and damage everything.
  A building needs to be able to "breathe" in order to get rid of the humidity that is generated inside.
  
  Styrofoam is good enough for that.
  
  I would not explode, it would implode.
- https://youtu.be/tnJms_3Gbuk

- 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
  
  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.
  
  What’s your source for this? It routinely gets over 100 here and buildings aren’t 80 degrees inside.
  
  pretty sure 50c to 35c is 15 degrees
  
  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.
  
  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.
  
  ok, but the cost of building a quanat is still pretty high and is not trivial to achieve.
  Can't have water flowing everywhere in a country for this to work.
  
  You've got a lot of great replies on how you're a wrong. But it is even simpler - your freezer works the same way as air con. And it's at -18°C even if your room is at +35°. That's all you need to know about air cons and their capabilities.
- 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.
  
  And what wind strength is required to achieve 10C decrease
  
  I do wonder what the humidity is. The drawing shows that the new air is mixed with air coming from the water canals below which I assume is very humid.
  Looks like its essentially a swamp cooler.
  So I wonder how the 30 with humidity feels compared to 40 without.
  Im now at a 32 but with the current humidity it feels like fucking 38!
- 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
- What a bunch of idiots! They should've just installed AC units.
  
  I hope that was a sarcasm, if so, add /s.
- Might not be a shivering 16 Celsius inside, but if it's the difference between dead and alive then it's probably good enough.
- Iran's traditional desert architecture masterfully navigates extreme temperatures through a combination of smart design and local building materials like mud-brick or adobe, which possess low thermal conductivity similar to sand. The thick walls of these houses act as a thermal mass, absorbing the intense daytime heat and slowly releasing it during the cooler night, regulating temperature swings inside the dwelling. This principle, paired with the utilization of design features like wind towers and qanat systems, helps to maintain a comfortable indoor climate. Some structures are even partially or completely built underground, using the earth as a natural insulator and benefiting from the surrounding cool sand. Consequently, it's this strategic interplay of materials, design, and the desert environment that enables these homes to remain cool during scorching days and warm during chilly desert nights. This is a gross oversimplification of thermal dynamics but it's the gist of it. It would be quite comfortable inside is what I am getting at.
- You can literally go there and witness these for yourself. It works. People live in Yazd right now in these old buildings. Newer constructions have air conditioning because building huge thermal mass retaining walls out of mud bricks is expensive. They keep ice all winter in buildings there from a thousand years ago cooled like this.
- Wikipedia claims "greater than 15 °C." Besides, even if you supplement it with air conditioning, that's 15 °C less ΔT worth of electricity you have to pay for.
- 35 is livable while you would be cooked alive in 50
- There is a note where I work that says the AC will not cool lower than 10C below outside to save on energy...

I love passive systems. The more passive the better.
- I assume the water here is doing the work. I didn't say anything about a closed system, just passive. Maybe that doesn't count as passive, I don't know physics all that well.
  
  These things are still there and if you aren't an American you can go to them. They are very nice and cool inside.
  
  The wind provides the work here. Wind and air flows.

- 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.
  
  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?
  
  Your link is broken
- 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.
- Wind powered swamp cooler. Basically a humidifier, but it does lower the temperature. I've heard people call swamp coolers air conditioning, so I don't think it's wrong.
  
  No, calling swamp coolers air conditioning is definitely wrong.
  If it's 100% humidity in your room, the swamp cooler is going to do absolutely nothing, but AC will cool it down and can even dehumidify a bit if you run it enough.
  Swamp coolers are awesome, but they only work in dry climates unfortunately.
- 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.
- I think the areas these were used in were fairly dry so they worked like swamp coolers.
- LOL Your comment makes it seem like you don't think that it couldn't possibly work, except that these things are still there and you can go visit them right now and feel how cool it is inside the buildings.
- The water doesn't actually have to be all that cool for swamp coolers, because it's the evaporation that cools the environment and warm water actually evaporates quicker.

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
- I cant speak to other parts of the U.S. but where I am from, people would design their farm houses so that when you opened all the windows, the natural wind direction wanted to blow through your house and naturally "cool" it. Coming from a house with AC, it seemed like a shit system lol, but i guess compared to being roasted in your stuffy house, it was probably pretty nice
- Frankly, ceasing to design homes and factories that way was a mistake. Stack effect ventilation is no less of an important part of green building technology today than it ever was.

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.

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.
- 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.
  
  A radiant floor is just a heat transfer system that still needs a hot/cold source. Evaporative coolers (aka swamp coolers) are really the modern day equivalent.
  @oshaboy@lemmy.world
  Maybe as a supplement to Air Conditioners.
  Swamp coolers only work when the outdoor air is quite dry (Arizona, Nevada, New Mexico). The resulting indoor air is very humid. Swamp coolers cannot make a big difference in temp. In NM they are perfect because the air is dry (too dry for comfort, IMO) and you only need to lower the temp by a small amount. So the resulting indoor air quality in NM is perhaps the best in the world for those who like ~65—70% humidity. A lot of swamp coolers in AZ have been replaced with A/C because the city temps have increased¹ to a point where swamp coolers cannot make a sufficient temp decrease. So I wonder if an AZ residents kept their swamp coolers going & added A/C. Note that A/C dries the interior air, so I suspect the swamp cooler might actually be make the A/C work harder in that scenario. If anyone knows something concrete about this I’d be interested in hearing it.
  ① One theory on the temp increase in AZ cities is simply more and more concrete covering the ground (roads, parking lots, driveways), less soil and vegetation. This means rainwater is drained off instead of having the large scale evaporative cooling effect of soil & vegetation absorbing water temporarily until it evaporates. IMO one correction (apart from reverting parking lots to gardens) is to get roofers installing vegetated rooftops. I really don’t understand why #vegetatedRooftops are nearly non-existent in the US. Pick any city and call every single roofing company in the region, and most likely not a single one of them can do #vegetatedRoofs.
- Meanwhile, they can make ice with nearly identical technology...
  https://youtu.be/tnJms_3Gbuk
  
  those don't make ice, just insulates them really well. the ice froze outside at night.
- passive house design

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.
- I came across this exact thing when researching air conditioning. And since I was interested in a good soltution for the tropics these Yak'chals as they're called are basically useless. The tropics regularly have dew points of 26°C and above.
  It can kinda work with an elaborate setup and a (liquid) desiccant cycle but in the end you still want the evaporation cooling outside, especially in the tropics where you have legionella practically instantly if you humidify anything indoors. And that will tank the efficiency. But it kinda works. The more humid the weather the hotter the regeneration of the desiccant has to be to work.
  Video 1 Experimental setup indoors to show the concept
  Video 2 Solar setup outside
- The very term Air Conditioning refers to a technical system, that is deliberately influencing aka conditioning the properties of the air.
  So yes, this is an ancient AC system.
  
  Cool, but that's not what we mean when we say AC. The meanings of words change over time and AC is used almost exclusively to refer to a specific type of device so unambiguous that I don't usually have to explain which exact type of device I mean.
  Otherwise literally just putting up a fan next to your window is technically AC. The term AC will lose all meaning.
- Thanks for pointing that out. My immediate thought upon reading the headline was how a/c could be implemented without electricity. I wondered if a compressor could be beast powered somehow. @FlyingSquid@lemmy.world should correct the title.

Wow, I thought quanat was a made-up word from dune.
- If "Kwisatz Haderach" is also a real thing that would be weird.
  
  It's derived from Hebrew.

Iran used to have AC. They still do, but they used to, too.
- All-encompassingly!

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

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.
- One othe trick was to build houses close to each other with narrow streets between them, so they would be in the shade of buildings most of the time. This way the city can actually be cooler than the open area around it.
  Of course this won't work anymore with large modern glass buildings or wide roads between them.
  
  The problem with that is it leaves little space for vegetation and soil, which give an outdoor evaporative cooling effect. The narrow streets approach should be combined with vegetated rooftops. An perhaps the vegetation should be able to thrive in the shade of solar panels.

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?

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

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
- That’s an informative robot
- I gotta wonder if the same was true for them to.
  
  Yes, humans often eat upwards of 15% sawdust in processed foods.
  Read the ingredients, where do you think cellulose comes from?

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
- Herodotus made an estimate of the rate of growth of the Nile delta, and used those estimates to challenge some conventional thinking about history and to make some predictions about the future. The ancients had a wealth of knowledge and competency. Probably much of it is lost.
  
  Humans have always been highly intelligent, they were just limited by the tools of their times. And yes much of their knowledge and innovation wasn't preserved to be built off of.
- Probably, almost 100% definitely aliens, yes, I have to concur.

wait isnt a similar system in the great pyramid?
- Can't really think of a way a tomb needs AC, but i'm eager to be proven wrong :-)
  
  Nah man, you have to cool all the grain that was store in there.
- Hadn't been invented yet.

interesting

I kind of want to try this myself

WOW EPIC

architecture like this would be better for the environment than industrial air conditioning
- This is not air conditioning. Not to be the "actually" stereotype, but air condioners literally "condition" the air by removing humidity (it was actually designed for this purpose, a side effect of removing the humidity was lowering the air temperature). This is simply good ducting and natural exchange.
  Good for the environment, yes! Air conditioning? No
  
  These condition the air by adding humidity, so you are actually wrong.

Seeing a lot of contrarians in this thread who just don't like that the Middle East had literally cool tech before America... pardon, before the people who stole America from the Americas, had literally cool tech.
Probs they are gonna call this thing "weapon of mass destruction" as a pretense for the next Yearly Oil Extraction invasion, conveniently ignoring that from an environmental perspective """modern""" AC is over twelve hundred times the WMD Iranian Air Conditioners ever were.