An ancient Persian technology for cooling Seville

An ancient Persian technology for cooling Seville

Seville, the capital of the region of Andalusia in southern Spain, is one of the hottest cities in Europe with temperatures often hitting 40 degrees in summer. Local authorities have long sought solutions to the complications caused by a further increase in temperature due to global warming. This includes the extraction of qanat, a technology that was developed in ancient Persia over 1000 years ago and then spread to other countries characterized by particularly arid climates.

The Persian qanats were a series of vertical shaft-like tunnels connected by a gently sloping culvert. The canal mostly emanated from an aquifer and made it possible to transport water over long distances using gravity without losing a large part of it to evaporation.

This principle was taken up and updated by the engineers who developed the CartujaQanat project in Seville: the aim is no longer to transport water, but to use it to cool a large part of a district and perhaps in the future the city. The culvert will carry cold water, a system of vertical louvers will allow fresh air to rise to the surface creating naturally cooled areas.

The project of the Municipality of Seville, worth five million euros, funded for four by the European Union, takes up an experiment already tried out in Seville for the 1992 Expo and improves it compared to when the water was pumped and partly with cooled with fossil fuels, the entire process is now powered by renewable sources. The site on which it will be built will remain the same, little used after the end of the exhibition and now destined to become not only a meeting place but also the headquarters of some companies.

This part of Cartuja Island, the piece of land between the Guadalquivir River and the Cartuja Canal, is being renovated not only with the new qanats, but also with covers for the amphitheater, sun protection, a water vapor system, new trees and a two meter high burial of the central square to protect it from the hot air currents. According to the project, all these measures should lead to a temperature reduction of 10 degrees and work “outside” up to 41 degrees.

Work on the project is expected to be completed by October, and the new qanat will also be tested on one of the city’s main streets, Avenida de la Cruz Roja, with “islands of relief” from the heat. For now, it is a solution that is limited to a few defined areas of the city and cannot solve Seville’s climate problems on its own. But if the results are as promised and the costs are affordable, the administration has indicated its intention to expand the network of modern qanats to other areas in the future.

At the same time, the municipality is implementing another series of measures to lower temperatures, including installing public fountains, covering streets and squares with shade sails, increasing the number of trees (5,000 are planted annually) and using building materials that protect the can reflect the sun’s rays.