
Yakhchal: Ancient Refrigerators (2009) - vezycash
http://eartharchitecture.org/?p=570
======
SwellJoe
This article nowhere mentions how they actually work. The article has that
"ancient mystery" vibe about it that I find so annoying about pop archaeology.
Googling it reveals they use evaporative cooling, which has also been used at
many places and times in history, probably independently discovered, which
makes it _more_ interesting to me than glossing over how it works.

In short, the WikiPedia article about yakhchals is much more satisfying:
[https://en.wikipedia.org/wiki/Yakhch%C4%81l](https://en.wikipedia.org/wiki/Yakhch%C4%81l)

~~~
bmelton
Agreed. Similarly, when I learned of the Indian technique of stepwall
evaporative cooling, I was shocked that something so misleadingly simple could
have been derived so long ago.

[https://www.treehugger.com/green-architecture/architect-
uses...](https://www.treehugger.com/green-architecture/architect-uses-ancient-
techniques-cool-modern-building-india.html)

But, of course people back then weren't any less intelligent, they simply
didn't have as much knowledge, probably due to the inefficiency of
transmitting knowledge from one generation to another without the use of
digital technologies.

If anyone is at all interested in ancient (or even just modestly old) cooling
techniques, 99 Percent Invisible had a particularly great episode in "Thermal
Delight"

[https://99percentinvisible.org/episode/thermal-
delight/](https://99percentinvisible.org/episode/thermal-delight/)

~~~
oldcynic
It's more shocking to realise how much we've needlessly thrown away.

There's a vast selection of old architectural techniques for controlling
environment that we've thrown away, preferring to bolt an AC unit to a hugely
inefficient building instead. Many are free, relying on natural convection and
material properties etc, others rely on movement of water like the Yakchal.

Some, but far from all, are coming back to be seen in things like passive
houses, but that remains an extremely small niche.

~~~
mmjaa
A lot of these forgotten technologies are revived in various contemporary
green movements - such as Permaculture and Earthship, for example.

Permaculture attempts to learn as much forgotten technology as possible and
re-apply it in a modern context for agriculture - the Earthship movement, same
but for architecture.

I think the biggest barrier to these forgotten technologies is the stigma
around the cultures they attract, as well as the hubris around the
technologies they supplant. Its very difficult to get someone who has grown up
with the Monsanto mindset to consider Permaculture concepts as a viable means
of agricultural production - likewise with Earthship.

Stigma and Hubris seem to be the number one causes of lost technology, imho.

[https://en.wikipedia.org/wiki/Permaculture](https://en.wikipedia.org/wiki/Permaculture)

[https://en.wikipedia.org/wiki/Earthship](https://en.wikipedia.org/wiki/Earthship)

~~~
oldcynic
A very good point. After reading the linked 99% piece linked above I'd perhaps
extend that to "stigma, hubris and marketing".

It's not very "modern" either is it? Hmm. I wonder if that's why we got the
post-war modernism school of architecture. :)

Someone used to monoculture and pesticides presumes dishonesty when hearing
about the productivity of permaculture - or even traditional mixed farming as
it's comparing mono yields against dozens of crops and livestock at the same
time from the acre.

It's a disappointment realising, after visiting a selection of old buildings,
just how much _nicer_ the old solutions are for humans to inhabit. You get
none of the harsh drying that you do with heating and AC, but you do get small
temperature variations and air movement that make it far better.

I haven't come across Earthship before, surprisingly, so thanks for that.

~~~
zamber
Regarding old buildings - it also applies to cities.

I once seen somewhere that Wrocław was designed to have air flow through the
streets freely to take out coal hearing induced smog.

Now, after the war, Polish architects unaware of that redesigned some of these
airways and even though coal burning is almost non-existent smog levels are
rising.

Cars and loss of greenery contribute to it but one can only wonder how good
air would have been if they would follow the original plan.

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geofft
There's no link I think, but I'm fascinated by the windcatcher:
[https://en.wikipedia.org/wiki/Windcatcher](https://en.wikipedia.org/wiki/Windcatcher)

The specific trick here appears to be that you connect a qanat (underground
canal, which routes water from the water table at a higher elevation to the
surface at a lower elevation) to the bottom of the structure, and a wind
catcher to the top, with its opening facing away from the prevailing direction
of wind. Wind blowing past the tower causes a pressure drop near the opening,
which draws in air from the other end of the qanat, which is cooler because
it's underground / next to water.

~~~
dmos62
I'm also fascinated by this. I've read about a similar setup where instead of
a windcatcher driving the airflow it's wood being burnt near the top of the
air channel. I can't recall who used this though. If anyone has some keywords
or links, I would appreciate it.

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benbreen
Got to see a bunch of these when I visited Yazd last summer (which in general
is just an amazing city, seems straight out of the Arabian Nights). The fun
you realize when you’re there is that they’re just one part of a massive
infrastructure of ancient technology that also includes the qanat system and
the amazingly beautiful wind towers. One theory for the origin of windmills is
that they were invented in Sassanid era Persia as well. Really impressive
stuff.

------
HillaryBriss
This semi-related TED talk also describes Yakhchal and describes a different,
local technique of ice production (as opposed to faraway mountains):

"How we can turn the cold of outer space into a renewable resource"

[https://www.youtube.com/watch?v=7a5NyUITbyk](https://www.youtube.com/watch?v=7a5NyUITbyk)

~~~
mncharity
Thanks! I've been playing with science education content around temperature.
'The universe was once as bright hot as the Sun, but it's been expanding, and
is now dark cold. So very cold. The Sun is still bright hot. So very hot. In
between, the Earth spins, mixing too hot and too cold. The atmosphere shades
us from the hot Sun, and insulates us from the dark cold. Ground and water
[buffer the night]. If Earth was much further from the Sun [atmosphere becomes
a few feet of snow].' And so on [closer to Sun; non-spinning and Mercury; no
atmosphere and lunar temps; more atmosphere and Venus; less buffered desert;
etc]. Sort of using a story frame of Sun vs space for teaching temperature in
primary school. Raman's work ties in nicely.

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singularity2001
Ever since I learned that Persian is related to English (with near identical
words for mother,father,daughter,brother…) I enjoy thinking of direct word-
correspondences (similar to most English-German pairs):

yakh chāl ~ ice hollow / Eis Kuhle/Halde <> hall ~ Höhle

yakh meaning "ice" chāl meaning "pit"

chāl <> cool@Kuhle

------
spraak
At risk of sounding like a ludite or troll, why aren't these used in modern
times? Earth architecture is so efficient and cost effective, it seems.

~~~
eesmith
I read an article on this topic about a month ago, but I can't find it now.

In short, cheap energy in the post-war US meant that mechanical heating and
cooling were affordable. Builders moved away from a vernacular architecture
style, which had adapted to the local environment, to a more standardized
style that was cheaper to make.

While it didn't cover this detail, I think another aspect was that many people
decided to move to other parts of the country, and wanted the architecture of
where they came from. For example, people from the NE who moved to the desert
SW and wanted a Cape Cod bungalow-style house.

The vernacular architecture in the SW is for thick adobe walls and small
windows. The walls are thick enough that it takes 12 hours for the heat of the
day to reach the interior, and help keep it warm during the cold nights. While
it's a better fit to the local weather, it's also more expensive to build than
a stick-built home + insulation + A/C and heating systems. (Traditional adobe
can be built using local mud, but that needs yearly maintenance, because the
rains will wash it away.)

~~~
spraak
Thanks for your perspective. I think cost is interesting, because the cost of
conventional building with air conditioning and heating doesn't seem to factor
the long term earth or environmental cost. My suspicion is that these actually
cost a lot more to maintain if cost to the earth and long term natural
resources is accounted for. But I'm just speculating so far.

~~~
eesmith
Yes, the price of fossil fuel use does not include the full impact costs.

The IMF report at
[http://www.imf.org/external/pubs/ft/wp/2015/wp15105.pdf](http://www.imf.org/external/pubs/ft/wp/2015/wp15105.pdf)
estimates:

> Post-tax energy subsidies are dramatically higher than previously
> estimated—$4.9 trillion (6.5 percent of global GDP) in 2013, and projected
> to reach $5.3 trillion (6.5 percent of global GDP) in 2015.

Secondary articles on the topic at
[https://www.pri.org/stories/2015-06-07/imf-true-cost-
fossil-...](https://www.pri.org/stories/2015-06-07/imf-true-cost-fossil-
fuels-53-trillion-year) and [http://priceofoil.org/fossil-fuel-
subsidies/](http://priceofoil.org/fossil-fuel-subsidies/) .

That's about $800/person for the world's population.

------
mirimir
Very cool! ;)

It's amazing what's possible with evaporative cooling in dry climates. If you
have enough water, anyway.

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dyukqu
[https://news.ycombinator.com/item?id=11719441](https://news.ycombinator.com/item?id=11719441)
\- Here is a good HN read/thread from two years back about Qanats. Yakhchals
was mentioned there.

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sadasivpet
This is available in India: [https://mitticool.com/product-category/earthern-
refrigerator...](https://mitticool.com/product-category/earthern-
refrigerator/)

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walrus01
In Dari any normal electrical household fridge is also called a Yakhchal.

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geff82
They also had climatized buildings, the „badgir“s.

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ychn432
Repost from 2012 :)
[https://news.ycombinator.com/from?site=eartharchitecture.org](https://news.ycombinator.com/from?site=eartharchitecture.org)

