An ingenious method of catching the breeze kept Persian people cool for millennia. The “wind catcher” could be making a comeback as an answer to emissions-free cooling.
The desert city of Yazd, Iran is home to a system of ancient engineering marvels including the wind catcher, or bâdgir in Persian. These mostly rectangular structures are a common sight in Yazd which was recognised as a Unesco World Heritage site in 2017, partly for its proliferation of wind catchers. These structures are now drawing the attention of academics, architects and engineers 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. Conventional mechanical air conditioning already accounts for a fifth of total electricity consumption globally, ancient alternatives like the wind catcher are becoming an appealing option.
The two main forces that drive the air through and down into the structures are incoming wind and the change in buoyancy of air depending on temperature – warmer air tends to rise above cooler, denser air. First, air is caught by the opening of a wind catcher and funneled down to the dwelling below. Then the air flows throughout the interior of the building, sometimes over irrigation systems for further cooling. Eventually, warmed air will rise and leave the building through another tower or opening, aided by the pressure within the building.
Fossil-fuel-free methods of cooling like the wind catcher might be reviving, but surprisingly they are already present in many Western countries such as the UK.