Climate Change and a lesson from the PERSIANS

by Dimitri Laspas

The Persians were great engineers and many examples of ancient underground cooling systems, irrigation systems and courier networks which would be equivalent to today’s postal systems have been discovered.

Located in a desert city in central Iran sits Yazd an ancient city full of amazing engineering feats.

Yazd is noted for its ‘wind towers’ or ‘bâdgir’ in Persian. These wind catchers can be seen all over the city and it is believed that the city has the most wind catchers in the world! The wind towers can be found elsewhere too in the Middle East, Pakistan and Afghanistan.

Located on the roofs of buildings, the impressive towers can be found as rectangular towers, but also as circular, square or octagonal shaped towers. The wind catchers can be uni-directional, bi-directional, and multi-directional. They are usually decorated too.

With today’s climate change crisis a hot topic and as the planet continues to heats up, this ancient technology could be become the basis for an eco-friendly solution, able to cool our buildings, thereby limiting the amount of electricity we use to power the ever growing number of air conditioning units.

These ancient wind towers do not require electricity as they are energy efficient and a green air conditioning unit!

The shape of the tower, as well as the layout of the house, the direction the tower faces, the number of openings it has, the pattern of the fixed inner blades, the height of the channels etc were all carefully designed and aligned to give optimum air capture and flow into and through the houses making them the perfect ventilation system.

The principle of operation is simple, with two factors pulling air into the wind tower (i) the incoming wind and (ii) the change in direction with the temperature. As warmer air rises above colder more dense air, the air is drawn in through the opening of a weather vane, and is blown down into the house, at the foot of the tower. The air then flows through the interior of the building, often over underground water ponds to make it even cooler. The warm air that was in the house will then rise leaving through another tower or opening, helped by natural pressure within the building.

When working to implement this kind of system into our world today, other key benefits are that they cost very little to maintain, they are silent unlike air conditioning units and they will still work as they are powered by nature if the electricity supply fails. Of course they will not work everywhere and would need to consider local weather and microclimate conditions to give maximum benefit.

So many of the solutions we need today can be found in our ancestors inventions. With modern materials and techniques they can be utilised successfully to create a better place to live for us all, in our unique home, the planet Earth.