Mastodawn

One of Europe’s Hottest Cities Rediscovers an Old Cooling Technique

By Laura Millan
August 8, 2023

"The streets of #Seville in southern #Spain were so hot that July afternoon that it felt almost impossible to walk outdoors. As temperatures approached 42C (108F), people scrambled to find shelter in air-conditioned homes, offices and public buildings. Yet, less than two miles from the city center, a cool breeze blew under a giant white roof.

"The structure is a part of CartujaQanat, an architectural experiment in cooling solutions that doesn’t rely on burning more planet-warming #FossilFuels. The site, about the size of two soccer fields, includes two auditoriums, green spaces, a promenade and a shaded area with benches. But its star performer remains hidden — the qanat, a network of underground pipes and tubes inspired by Persian-era canals.

"The grid of #aqueducts can lower surrounding temperatures by as much as 10C using just air, water and #solar power, according to Emasesa, the Seville public water company that helped to build it. The system is modeled on ancient tunnels dug to bring water to agricultural fields that were first documented in what is today #Iran. The Persians realized 1,000 years ago that the running water also cooled the air in the canals, so they fashioned vertical shafts to bring that air to the surface.

" 'This is not an air-conditioning system like the one you may have in your home,' says Juan Luis López, the project’s supervisor and an engineer at Emasesa. 'We use natural techniques and materials to reduce temperatures.' "

Read more:
https://www.bloomberg.com/features/2023-seville-spain-extreme-heat/

Archived version:
https://archive.ph/36fz1

#SolarPunkSunday #History #PersianTechnology #ClimateChange #KeepingCool #ExtremeHeat #AncientTechnology

Seville Weather: Heat Wave 2023 Measures Include a Very Old Cooling Technique

Cities are the first line of defense in humanity’s battle against deadly heat. Bloomberg Green’s Hot Cities series looks at changes some of the world’s hottest cities are making to protect their people from extreme temperatures.

Bloomberg

Aaron Jun 23, 2025

@DoomsdaysCW We could use something like this here in Texas, too!

VulcanTourist Jun 23, 2025

@hosford42 @DoomsdaysCW

Similar but not nearly so efficient: in the desert of southern California, there was a population that lived in corrugated metal structures, and they would drape burlap over them and then dribble water slowly over the burlap. The evaporative effect lowered interior temperatures dramatically.

Aaron Jun 23, 2025

@VulcanTourist @DoomsdaysCW I was thinking the other day, upon observing a food truck parked under a former gas station canopy, that this probably helped reduce the temperature a *lot* in the truck. And then I wondered if a second, air-gapped roof over a house might be worth the expense. Let the canopy catch the sun, and the breeze flows between it and the actual roof of the house, siphoning off the heat instead of it soaking through the attic and down into the house proper.

Aaron Jun 23, 2025

@VulcanTourist @DoomsdaysCW Probably a goofy idea, but I'd like it if someone who's a real engineer did an actual analysis.

VulcanTourist Jun 23, 2025

@hosford42 @DoomsdaysCW

Not a goofy idea at all. European A-frame houses with dark roofs are just about the dumbest fucking house design EVER. There's a lot that can be done to improve upon it.

VulcanTourist Jun 23, 2025

@hosford42 @DoomsdaysCW

When I lived in a mobile home, I devised a project that I never implemented to cover the south-facing side and roof with a latticework and then plant perennial vines to train over and cover it. The latticework would have been "airgapped" from the mobile home.

It would have dramatically reduced summer temperatures.

vxo Jun 23, 2025

@hosford42 @VulcanTourist @DoomsdaysCW Solar panels on a roof usually create this second air gapped roof effect, and it works absolute wonders.

VulcanTourist Jun 23, 2025

@vxo @hosford42 @DoomsdaysCW

They would. I wouldn't have considered them at the time because the cost would have been substantially more than what I considered instead for passive cooling.

vxo Jun 23, 2025

@VulcanTourist @hosford42 @DoomsdaysCW if high winds aren't a concern where you are, a shade cloth canopy would be easy

VulcanTourist Jun 23, 2025

@vxo @hosford42 @DoomsdaysCW

High - and dangerously gusty - winds are indeed an issue here. I had one permanent welded iron canopy rendered impermanent by them.

DoomsdaysCW Jun 23, 2025

Yikes! @VulcanTourist

VulcanTourist Jun 23, 2025

Then there's this (from the article):

“Pilot projects are very interesting as experiments,” says Curro Oñate, a biologist and president of Red Sevilla por el Clima, a citizen group that advocates for more climate measures in the city. “But they are totally insufficient because they benefit a very small share of the city’s population — and usually the most privileged.”

It goes on to detail how Seville's poorest neighborhood doesn't even get trees, much less ingenious public works like CartujaQanat.

This mirrors my own experience living in one of the ghettos of my own city, where large shade-giving trees are a rare occurrence and most of the trees that were here when I first moved here have been cut down AND NOT REPLACED. This is in a city that is nicknamed The City of Trees because its affluent downtown area is virtually covered by them.

There is nothing egalitarian about projects like this one.

DoomsdaysCW Jun 23, 2025

@VulcanTourist That sucks. But the techniques involved can be adapted/used/co-opted by more egalitarian folks. And yeah. Cutting down trees is ridiculous! I had a great conversation about that with a friend this weekend, who was an Earth First "tree sitter".

lolcat Jun 23, 2025

archived, non-paywall article on the topic:

https://web.archive.org/web/20211130083925/https://www.uia-initiative.eu/en/news/cartujaqanat-recovering-street-life-climate-changing-world-journal-2-how-sevilla-moving-needle

CartujaQanat – Recovering the Street Life in a Climate Changing World Journal 2: How is Sevilla moving the needle in the fight to urban climate transformation

Sevilla in Spain, will be the battleground of Europe for extreme urban heat. A pilot space containing an amphitheatre, an underground gallery and open-air facilities located on Avenida Thomas Alva Edison within the large Expo ’92 Park of Sevilla in Spain, is being reconverted into zero-energy consumption pubic space and delivered to citizens, as an innovative co-managed space for public events and leisure. Functioning as a test-bed for a diversity of solutions, the project CartujaQanat can be transferred to streets and other large public spaces offering a new model for urban street regeneration through infrastructure, jobs re-invention and place-making. Sevilla is the hottest city in Europe expecting to record temperatures of 50 degrees Celsius for consecutive days over the next five to ten years. How does a city safeguard its public life under conditions of extreme heat? And how is cooling under such temperatures achieved with zero-net energy consumption? CartujaQanat aims to provide an answer.

UIA - Urban Innovative Actions

DoomsdaysCW Jun 23, 2025