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‽
Sorry my point wasn’t that we shouldn’t explore other options to use instead of/in tandem with A/C. I was entirely pointing out that the use of an AC/heatpump is by itself, in absence of the context of what is used to power it, a non issue as its one of the most efficient electric heating/cooling technologies we have.
Wind catchers could be, and likely are a great technology to adapt for wider use, though I can’t speak to that, I’m not an HVAC engineer.
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.
Not necessarily in your house. I’m talking about the design of the units from when you were a child (Many public buildings in the EU have AC regardless of houses not having it). AC was invented in 1901, and has come a very long way since then, and we have begun combining it with old principles to extract the best of both solutions
Combining modern refrigeration/cooling techniques with well designed passive systems that exploit material properties (Heat capacities, transfer coefficients, etc.) to their advantage is the future of HVAC. It started with CFCs and knowing we could exploit their boiling point with mechanical force to chill air beyond the outside air temperature. Who knows where science and engineering may take us next!
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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
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.
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.
It’s the internet, you never know. In person, by how the person behaves, you know if he’s being sarcastic or not. On the internet, not so much. It’s just text and I’ve seen people who were quite serious.
I think at some point the /s isn’t needed
Might not be a shivering 16 Celsius inside, but if it’s the difference between dead and alive then it’s probably good enough.
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 love passive systems. The more passive the better.
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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.
The water does not perform work in this instance.
I do not think you’re trying to say the water “does work” in the physics sense, but to clarify, the water is just a large heat sink that has a much higher heat capacity than air. You can heat the water with air (which in turn cools the air), and that water can hold MANY times the heat (per unit mass) that the air can. Water also has a higher thermal conductivity than air. Allowing it to absorb and pass heat very well. This water is in the ground which also acts as a massive heatsink.
The air passes heat to the water which then passes the heat to the ground effectively cooling your air feed. A quick look online says current soil temp in Iran 21 inches deep is 35C or 95 F. That is your lower temperature limit. It’s physically impossible to become colder than the soil temperature (in this instance, as that is your lower temperature bound for heat transfer, in reality you wont even get there, because your driving force for heat flow is gone at that point) without putting in mechanical work (which is what a compressor does in your air conditioner) to compress your cooling fluid so that it may be evaporated repeatedly to exploit the tranfer of heat into an evaporating substance
Why only 21 inches? Soil temps aren’t stable until like 6 feet down, and then it’s closer to 12 C.
That is the deepest depth I could find being actively tracked on the website I ended up on. I did not wanna do a deep dive into “great” average soil temp data lol. If you have a good source of data I will gladly change my comment to include the updated numbers. I wanted to say the average soil temperature at depth is ~50-55 degrees F, but I hopped online to make sure that was not a number that I know to be true due to where I live. Good to know that its roughly 6 feet where it stabilizes
If you go down deep enough the earth temperature is stable at 12 C. But I’m pretty sure that’s like thousands of feet down. Geothermal rigs drill 500+ meters (1600 feet) down. Having a hard time finding a source on the stable earth temp though.
I mentioned 6 feet because it’s well below the frost line where I am, but I guess in that part of Iran they probably don’t have to worry about that.
Mostly I was just wondering if you had found something on how deep those waterways were actually built.
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.
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.
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?
