For our first exploration let’s visit ancient Persia and the unique wind catchers. Ancient Persia was full of hot days, cool nights, and low humidity. They needed ways to tame the weather for their own comfort as well as for the storage of water and food. There were a few simple methods such as: building their homes out of thick mud to increase the insulation and building everything tall to create shade during the day. A more complex solution was to use nature’s benefits to moderate temperatures with something called wind catchers. There were different types of wind catchers in different locations due to their varying climates. Let’s take a look at some of these concepts.
Air Intake Designs
The first design we are looking at creates the effect that an electric fan has in your home during the summer: it doesn’t actually cool the air, but it does cause airflow, which makes a cooling effect. This type of wind catcher consists of a tall tower with one opening facing the direction the wind most often blows toward. The wind enters the opening and is forced downward and into the main area of the building. This starts a cycle of moving air throughout the building.
Wind Initiated Outflow designs
There are types of wind catchers that transfer heat and rush cold air through the building. One type is wind powered and works with an underground water canal called a qanat. The tower has an opening facing away from the source of the wind. Due to the moving air outside, the inside air is drawn up and out. With the air leaving there is a decrease in pressure near the exit and air is pulled in from the other end where there is an opening to the qanat. This new air is cool from the water, and it cools the rest of the building as it travels through.
Hot Air Escape Designs
When there is no wind blowing there is still a type of wind catcher that is applicable. This type uses the difference in pressure from hot air and cold air to cool the building. Since hot air is less dense it rises and will want to escape out a vent in a tall tower. While this design sounds simple it can cool lower levels to almost a frigid state.
Now that you understand wind catchers you might want to see them for yourself. A common place to look would be Egypt or Iran. I would suggest visiting Yazn, Iran, because that is where some of the tallest and most impressive wind catchers can be found. However, you may not need to travel far because similar towers can be found across the globe today due to their green design. The visitor center at Zion National Park has added a wind tower with many similarities to one of the ancient Persian air intake designs.
I hadn’t know anything about Persian wind catchers previously, and I learned a lot from the Circle of Ancient Iranian Studies. It’s amazing how technology from so long ago can be relevant in new developments today.