Ancient Iran had air conditioning
Ancient Iran had air conditioning
I said “around” 10c. An article said from 8 to 12 Celsius. There’s a paper that said from 46c exterior temperature, the tower can cool the interior to between 34 and 38c. I just rounded things up.
For a solution, we can generate green energy with solar panels and heat pumps.
As I said, the way the tower works is super interesting, but 34c is still very hot to be comfortable.
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 admitting defeat rather than having to think in terms of freedom units.
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.
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.
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.
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, 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.