An ancient Persian way to keep cool (2021) | Hacker News Reader

An ancient Persian way to keep cool (2021)

bbc.com

178 pointsthunderbong66 comments

This doesn't solve humidity issue unfortunately. Most hot areas around the world are also very humid and that's where air conditioneers with all closed windows/doors will be preferred. Open rooftops also pose a lot of challenges like water and smell leaking, animal invaders start to get in etc.

There was an article on HN recently how ceilling fan improves air conditioner performance and I actually seen a major improvement in my own house - it's awesome! I wonder if some architectural features like the one in the article could be somehow used with air conditioning to produce a similar effect.

I spent all the June September period at 30+ Celsius degrees day and 20+ night and no air-conditioner despite having two of them. I used standing fans. The disadvantages are that you must be in their wind tunnel whilst an air conditioner covers the whole room. The advantage is that they cost less and can be carried around the house. Rooms facing North with no sun hitting them also helps. South facing rooms would have required air conditioning.

What’s the humidity like? I’ve been in 100+ (37+) degree desert weather that doesn’t compare to 80+ (26+) degrees with 60% humidity. If I lived in a dry climate that could be an option. When I wake up in the summer it can be 90-100% humidity and opening windows causes all that water vapor to come inside worsening the heat problem.

I can't say for sure because I couldn't find historical data about humidity yet. I'd say between 20% to 50%, occasionally more.

So you had two air conditioners - why did you not use them?

They were already in the house. Some random reasons:

1. Fans are cheaper to operate

2. Their effect is instantaneous

3. Lower maintenance: no filter cleaning, etc, only a dust cloth sometimes.

4. They have remote control and timers too.

With energy recovery ventilation, incoming fresh air can be pre-treated using the cool, dryer exhaust air to reduce the energy required to cool it while still allowing fresh air in. That, combined with solar PV, good building design (shading, correct aspect etc.) and good insulation is probably the best balance of comfort and efficiency.

We spray foamed our entire house and the humidity shot through the roof in the late spring and summer months (65%+) and had to run a dehumidifier constantly negating any benefit from our solar panels. Fall and winter were great because we saw a major decrease (like 40%) in natural gas usage compared to that time frame the previous year. However, our home was built without a scuttle because they weren't code yet meaning that our home air got stale quickly and wasn't able to be exhausted through the now spray foamed air holes. We then installed an ERV and it made all the difference in the world.

This is what everyone seems to miss about air conditioning. It's convenient that one device lowers both the indoor temp. & the humidity. But in the case that I had to choose only one, I would lower the humidity. Any healthy adult can stay cool in a low humidity environment by sweating.

Discussed at the time it was published: https://news.ycombinator.com/item?id=28138844

It is very easy to cool a city that is 1200 meters above sea level and with low humidity. I wouldn't be surprised if temperatures during the nights fall to 0C or below during the cold season. Any kind of evaporative cooling will work very well there.

History With Kayleigh did a nice video on this about a year ago:

“Air-Conditioning Invented In 3100 BCE? Windcatchers Yzad”

https://youtu.be/gC8BU4GdFzc

I don’t see the paper talking about the efficiency of such buildings. I would be interested to have such info in there.

Its hard to talk 'efficiency' as they work in different ways.

Some actively 'cool' the air (including through contact with ground or water, or evaporative cooling from plants), some don't further cool the air they cool people through airflow like an electric fan (effectively the human cools themself through evaporation).

Their function will of course also vary through the day and year depending on literally the way the wind blows.

Many also were designed to be attuned to local wind and climate conditions which would have changed over centuries since so its also hard to judge their original function.

Could we have an idea of the temperature change we can expect? For example, if it's 40 degrees celcius outside, can the mechanism go down to 30? 25? 20?

It's a wind catcher. It can't cool below the temperature of the wind without evaporative cooling.

Which in that case, it wouldn't be a wind catcher.

An aside: I'm struck how beautiful are the wind catchers. A form of beautiful architecture with a practical function, seamlessly rising up from many buildings.

More images via search: https://duckduckgo.com/?q=Yazd+wind+catcher&t=ffab&iar=image...

Any guess as to why there are multiple poles sticking from the sides? Reinforcement? Method of adjustment? Place for someone to stand while working on the structure? An inside joke meant to confuse foreigners?

Gophers have been using a similar but smaller system to keep their burrows flowing with fresh air for tens of thousands of years.

And termites. Nature's amazing

The ancients knew a lot. Also check out Petra, the capital of the Nabataeans.

https://en.m.wikipedia.org/wiki/Petra

These people were traders (capitalists) and built an incredible city in the desert. This was enabled by extremely efficient water harvesting (like in Dune) and by being extremely difficult to get to, making armies starve and die of thirst en route. It could be defended with a small force.

Having been there, Petra is quite weird: we've all seen the facade of the Treasury in Indiana Jones, but there's nothing inside, just a tiny little hole. The working theory is that it was in fact just a mausoleum, and almost all the rock-carved structures are actually just tombs, with the city itself almost entirely lost to the mists of time.

Capitalism is not just about trading, this is an anachronism, maybe deepen your historical & concept research if you care about objectivity. Also see: equi-vocation: etymologically, calling things the same. Aka confusion. https://www.etymonline.com/word/equivocation

Fascinating. Being in a long drought in the southwestern US, we could learn so much from other civilizations like the Petra people

Ancient Persian? The article starts explaining how the Egyptians invented the technique..

(2021)

> (With conventional mechanical air conditioning already accounting for a fifth of total electricity consumption globally, ancient alternatives like the wind catcher are becoming an increasingly appealing option.

The descent into religion. Denial that better modern solutions work at all. Acceptance than an old (before the gaze of modern criticism can fatigue it) technology is better because it is older. The fantasy that a problem exists due to the existence of man, innate in his original sin of taking breath at all. The legions now employed to drive these new dogmas is astounding. Lastly, abandoning reason, to presume air flow by convection is the same as cooling.

Although I agree that a lot of the environmentalist movement is transforming into religion, I don't think this is a good example of it. In locations with cheap land and feasible climate, passive cooling achieves cooling whilst using no power.

It's not better because it's older, it's better because it is more efficient.

More efficient than what?

If you know anything of the religious extremists destroying our cities you know there are enough that they will take something like this, try and integrate it into a design, get some engineer from the same denomination to approve it and put it in a building to grease the moral self applauds of the planning committee desperate to please the gods.

There is a building in my city, fully built, which decided to put 3 wind turbines at the top of it. If you are familiar at all with wind turbines you know they create a lot of vibration and noise. They shouldn't be built in high density areas. Of course this meant those living in the building within 15 floors near the turbines experienced constant noise, and vibration. They are now permanently disabled.

It was allowed to be built where no tall building existed mainly because of these talismans.

https://en.wikipedia.org/wiki/Strata_SE1#Sustainability_clai...

> The turbines are of course not merely decorative but have a function which is directly related to the Elephant’s status as an energy action area and to the achievement of the zero carbon growth which is a key objective of the framework.”

Genuflection

More efficient than active cooling.

Your city has it particularly bad, don't let that convince you that everywhere is like London. I live somewhere much more pragmatic, and passive cooling is used without the religious issues you predict.

There is definitely some weird pseudo religion around things which are old. Anyone who says "cavemen ate like this, that means it's good for you" don't know what they're talking about. That's not the case here.

Let me rewrite this as a modern invention: Someone invented a wind powered cooling system. No other fuel is necessary and it will work for years with minimal maintenance. The mechanism is simple enough that they can be built both in large metropolitan areas and smaller, struggling regions.

It's absurdly inefficient and cumbersome compared to other options. The reason people tolerate such ideas is the fear of the cost of electricity.

The cost of electricity in the west has been a matter of false scarcity imposed by religious economic terrorists who sacrificed our stability around the era of the Kyoto Protocol.

Simplicity. Simplicity prevails majority of the time. Simplicity and alignment with vs fight against.

You discount "the old" perhaps with the misguided assumption that we know better because we live now and not then. As if civilizations have not risen and fallen countless times, and as if humanity has not been forced to re-learn the forgotten lessons again and again.

Simplicity is the hardest to accomplish, because it requires thorough understanding, patience, and perspective -- something 90% of us don't have.

I will leave you with a modern example: a four-way traffic-light-controlled intersection vs a roundabout. The former leverages modern technology (maybe even ML with data from a larger traffic network!), and yet it is less safe and most of the time generates more traffic backup than the latter. The latter has no external dependencies, and instead shapes the space in such a way as to make dangerous collisions impossible.

If anything is a religion, it's the blind belief that "newer is better"

I discount this because it doesn't make sense in high population density cities. The age simply ads a mysticism that makes it attractive to weak minds.

And to your roundabout Vs traffic lights the space/geometry of the area available is often the difference in choosing which to build

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