Wind Towers: How Ancient Civilizations Harnessed Wind Energy
Notice: this blog discusses ancient Persian wind catchers. If what you are looking for are modern wind turbines, you can read about it here.
If you think we are the first civilization to harness the power of the wind, you couldn’t be any further from the truth. From ancient Greek windmills to wind-powered sailing ships, those that came before us knew all to well about how useful the wind can be.
In this blog, we will center our focus on a very specific usage of wind in history. Going back several thousands of years, the Persians built wind towers/wind catchers that provided unpowered ventilation to their homes amidst their scorching desert heat.
The Architecture of the Wind Towers
The ancient Persians were masters of architecture. For their capital city of Persepolis, they created some of the most impressive designs of the forgotten world world, including the iconic wind towers.
Wind towers are an ancient piece of Persian architecture designed to provide ventilation to a building. Wind towers took the form of a tall chimney-like figures, protruding several meters above homes, mosques and other structures. Either a column or up to four columns of wind towers will be erected on top of a single building.
They worked by trapping wind blowing across the desert and forcing them down the “chimney”, and into the building. There would often be an exhaust located on the other end of the building, that lets the air out, thus creating an effective airflow.
Another kind of wind catcher would have a tunnel dug underground, directly connected to the chimney of the wind tower. Air forced down the tower would pass through the “tunnel” before entering the property. The idea behind it is that the soil would cool the air sufficiently before being redirected inside the home.
In deserts, the thermal inertia of soil means that the soil would maintain the warm temperatures of the day during the night. While outside temperatures fall drastically in deserts during the night, sometimes all the way down to freezing point, the wind tower would force air through a tunnel of warmer soil before entering the house. The cold air-turned warm by the soil would then warm up the building just enough for inhabitant to reside a little more comfortably.
Another type of wind tower used water as a heat reservoir to cool and warm homes. A pool of water would be located at the bottom of the tunnel, which would evaporate as it absorbs heat from the flowing warm air. The cooler air (as a result of losing its heat to the pool of water) would then enter the building, cooling it sufficiently.
Wind towers are made out of materials such as sand, brick, and clay, and they are usually very tall. Some of the tallest wind towers in the world are located in the Middle East and Africa, and they can reach heights of up to 110 feet.
These structures were very effective at cooling buildings. Researchers believe that wind towers may have cooled homes by up to by about ten degrees Celsius (that is 50 degrees Fahrenheit). This is largely impressive given how simple the structures are and how far back they were first used.
The History of the Wind Towers
Harnessing the power of the wind is not new to the world, and it has certainly been around for centuries. Given its rich history, it is no surprise that Persia has some of the oldest wind towers in the world. While the exact location the story begins is still under debate, Persians are not the only civilization in the ancient world to use this technology.
There have been various designs of wind catchers found across Africa and the Middle East. In fact, it is debated whether the first wind catcher appeared in Egypt or in Persia.
The first historic account of a wind catcher comes from a Persian poem, dating back to the 5th century. However, the earliest archaeological evidence of a wind catcher only date back to the 14th century, in Persia.
In Egypt, paintings that date back to 1300BC have been discovered, depicting what appears to be a wind catcher on top of Pharaoh Nebamun’s royal residence. Whether the paintings depict wind catchers are a subject of controversy, leading Iran (modern day Persia) and Egypt to be on opposing ends of the pool.
Wind catchers began to appear in many other places across the world, including in some Western architecture, as we move forward in the timeline. Quire popularly, wind catchers began to appear in architecture across Dubai towards the end of the 19th century. Today, many Persian wind catchers still stand as impressive examples of architectural masterwork, and they are popular tourist attractions.
The use of wind towers in ancient architecture is an interesting example of how we are simply rediscovering the what those who came before us have already founded. Today, wind catchers are making a comeback in some architectural designs, as a greener alternative to air conditioning.
Wind towers worked by “trapping” wind through openings in a chimney shaped tower, and forcing the air down into the building. There were other models of wind towers that relied on an underground tunnel or a pool of water.
By using the power of the wind, these structures provided unrivaled ventilation and cooling in hot climates, especially in the scorching heat of the Middle East and Africa.
Today, many of these towers still stand proud across Iran and other parts of the world, acting as beautiful reminders of how technology never truly gets lost in time.