Windcatchers and Keeping Cool

David Trammel's picture

We tend to act like the modern invention of air conditioning has been with us forever and is universally available. The heat emergencies this summer in the North West of Washington, Oregon and Canada showed that just isn't true. There are places in even "1st World America" where being able to cool your home at a flip of a switch is not an option. Let alone poverty making its mark. In the coming decades as climate change and economic collapse leave more and more at risk of heat emergencies and persistent high temperatures, finding ways to cool that do not take expensive equipment and access to electricity will be critical.

That's why I found this article of interest,

"The ancient Persian way to keep cool"

"The city of Yazd in the desert of central Iran has long been a focal point for creative ingenuity. Yazd is home to a system of ancient engineering marvels that include an underground refrigeration structure called yakhchāl, an underground irrigation system called qanats, and even a network of couriers called pirradaziš that predate postal services in the US by more than 2,000 years. Among Yazd's ancient technologies is the wind catcher, or bâdgir in Persian. These remarkable structures are a common sight soaring above the rooftops of Yazd. They are often rectangular towers, but they also appear in circular, square, octagonal and other ornate shapes.

Yazd is said to have the most wind catchers in the world, though they may have originated in ancient Egypt. In Yazd, the wind catcher soon proved indispensable, making this part of the hot and arid Iranian Plateau livable. Though many of the city's wind catchers have fallen out of use, the structures are now drawing academics, architects and engineers back to the desert city to see what role they could play in keeping us cool in a rapidly heating world.

As a wind catcher requires no electricity to power it, it is both a cost-efficient and green form of cooling. 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."


I wonder how you could retrofit an existing typical American home with something like this?

"There are two main forces that drive the air through and down into the structures: the incoming wind and the change in buoyancy of air depending on temperature – with warmer air tending to rise above cooler, denser air. First, as air is caught by the opening of a wind catcher, it is funneled down to the dwelling below, depositing any sand or debris at the foot of the tower. Then the air flows throughout the interior of the building, sometimes over subterranean pools of water for further cooling. Eventually, warmed air will rise and leave the building through another tower or opening, aided by the pressure within the building.

The shape of the tower, alongside factors like the layout of the house, the direction the tower is facing, how many openings it has, its configuration of fixed internal blades, canals and height are all finely tuned to improve the tower's ability to draw wind down into the dwellings below."

I am guessing, you'd first want to see how much consistent wind you got on a Summer or early Fall day. If trees or other tall obstacles were in your area, you might not get any usable wind. You'd need to build a fairly tall tower attached to your home, then funnel that air down to the interior. A basement would certainly be a help. A pathway for hot air to exit would be important too.

What other things would you need? Is this a technology that would be useful to a wide use or more of a specialty modification?

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I thought this would be a great idea for my home, since I live in a desert, but I could see how to attach it to my house. In Death Valley at Scotties Castle they have used many of the same principles to cool the building. The ceilings are tall and in one room there is a waterfall running down a tiled wall that is meant for cooling. I don't think they were quite as good a window placement, but I don't believe it was built with AC in mind although it has probably been added since.

I guess the closest I get is the placements of the window fans.

Retrofitting a typical one-story ranch looks hard.
On the other hand, if you're building new, then passive heating and cooling can be built-in.

The correct orientation on the land does a lot all by itself.
Then add the cooling tower and the magic of masonry retaining its temperature and these wind catchers look useful and doable.