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Ancient Iran had air conditioning
(lemmy.world)
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this post was submitted on 24 Jul 2023
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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.
The AC is also small compared to a literal building with a sewer underneath and doesn't require a windy day. Trade offs
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
Do we know it's more efficient? Has anyone done the math?
What’s your source for this? It routinely gets over 100 here and buildings aren’t 80 degrees inside.
~~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. :)
Yes, that sounds about right - the relative effect of the tower probably depends a lot on various factors like how windy it is, if extreme heat occurs only for a day or if it has been ongoing so that the water under ground is heated as well, etc.
These comments were in response to @Gangreless, who stated that a modern AC "can only cool about 20f below the outside temperature". I didn't catch that it was fahrenheit first, and now that I know I am happily backing off rather than having to think in terms of freedom units.
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.
20 degrees is just a rule of thumb most ACs have a specific temperature change they're designed to do. You can go past it, that's just what the intented to do and it might not work as well or be able to do it. Fwiw I'd always heard 30 degrees farenheight for most window units. Had an hvac guy explain it to me years ago but fucked if I remember how it works
E: not sure why I'm getting downvotes this is like a very common thing. Google it https://frederickair.com/home-comfort/reduce-the-stress-on-your-ac-with-the-20-degree-rule/
pretty sure 50c to 35c is 15 degrees
I wonder how he got his number, it makes no sense.
EDIT: oh, he just randomly mixed °C and °F, because why not...
Fucking Americans
50c is 122f, 35c is 95f so he went 50c-35c = 122f-95f = 27f because why the fuck not.
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.
Are you my brother? Whenever I go to his place I feel like I'm going to get hypothermia lol
Heat pump doesn't do that for us. We set it at 78-79f in the summer and it feels cool enough & keeps the house from molding.
Evaporative systems like the one pictured only work in the desert though. So if you have lots of water, it's humid and you can't use evaporation to cool, but in places you can use evaporative cooling, water is scarce. It's still very cool tech, and everywhere can benefit from more intentional design of buildings.
Your heat pump will definitely do it, it’ll just take a long time.
The 20 degree figure everyone is throwing around is actually supposed to be the difference between the return air temperature and the supply air inside your home
If you have 80 degree air in your house, 60 degree air should be coming out of your vents. Once the 60 degree air has cooled down the house to 70 degrees or so, 50 degree air should be coming out of your vents. And that’s about the theoretical limit for home air conditioning, as anything lower means the cooling coil is below freezing and will get damaged by ice, there’s usually a safety switch that prevents things from getting too cold.
Now the outside coil needs to be hotter than the surrounding air to actually push that heat out of the coil and cool off. Most places around me are designed for a 95 degree summer day, so will have a refrigerant temperature of about 120 degrees, in order to move that heat. Your compressor needs to be able to compress the refrigerant from your cooling coil until it’s about 30 degrees F hotter than the outside air. The hotter it is outside, the harder it is on the compressor. But it will eventually do it if you let it run long enough. Whether or not you want to pay for all that electricity is another thing entirely.
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.
Most countries in the world quite literally have water flowing everywhere already.
But don't "swamp cooling" systems like the one in the OP not work well in humid environments? Sure, I have running water at home, but I also live in an incredibly humid climate.
I was more imagine something like the opposite of a district heating system and then using colling ponds or towers to disappate the heat from the system..
Don't you have water to drink at home? Or in the bathroom?
Modern plumbing uses pressurized pipes that are completely full of water, and can thus flow uphill, as long as the elevation gain doesn't exceed the head pressure from the water tower or pumps. That makes such pipe systems relatively cheap and easy to build.
In contrast, qanats require large conduits with space above for the air to flow through, using open channel flow. That means the entire system needs to be designed with a gentle downhill monotonic slope. That's doable (the wastewater and stormwater sewer systems are designed that way, for example), but it's more expensive and would require a lot of re-work if you wanted to convert over the existing water distribution system.
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.
And get it has way more upvotes than down, just like reddit.
Reddit is sipping here at a rapid pace...
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!
Well, Iran is mostly a desert so I assume the air must be very dry.
That would be another benefit of having the water underneath evaporating up, increasing air moisture.
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
Might not be a shivering 16 Celsius inside, but if it's the difference between dead and alive then it's probably good enough.
What a bunch of idiots! They should've just installed AC units.
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.
35 is livable while you would be cooked alive in 50
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.