How it began
The work began in 2009, when Qatar was bidding to host the 2022 FIFA World Cup. The Supreme Committee for Delivery and Legacy asked Qatar University for ways to deal with summer heat during matches. Saud Abdulaziz Abdul Ghani, a Sudan-born professor of mechanical engineering at the university, led the project, which was funded by the Qatar National Research Fund. He said the idea drew on his doctoral study of air conditioning for a car, applied on a much larger scale.
Before it existed
According to Ghani, large design firms had never designed an air-conditioned open-air stadium before, so no standard approach existed. Bidding countries usually presented stadiums as design ideas rather than as a technology. Architects normally led the design of a venue and then asked mechanical engineers to make the cooling fit. Pumping large volumes of cold air into an entire open bowl was, in his words, inefficient at best.
How it works
The system cools only the playing field and the stands, up to about two meters above the highest row of seats. Cold air is blown toward the pitch through football-sized nozzles and reaches spectators through small diffusers under each seat, angled so the air arrives gently at ankle level. The air is then drawn back, filtered, cooled again and pushed out, so the stadium holds a bubble of cold air. The shape of each stadium, the size of the roof opening and even the facade color were tuned with 3D-printed models in a wind tunnel and with computer simulation to keep hot outside air from entering.
What changed first
Khalifa International Stadium, renovated and completed in 2017, was the first tournament venue to use a version of the system, and Al Janoub Stadium followed. FIFA reported in 2019 that the technology was estimated to be 40 percent more sustainable than existing techniques and that a stadium needed to be cooled only two hours before an event. Changing the facade of Al Bayt Stadium from a dark to a light color lowered the inside temperature by about 5 degrees Celsius.
What lasted
Different versions of the system were planned for all eight World Cup stadiums, to hold them at 18 to 24 degrees Celsius so the venues could be used all year. Ghani chose not to patent his under-seat diffusers, a decision he described as a service to the scientific community. The project was also unusual in that mechanical engineers, not architects, led the design process.
Where it stands today
The same approach has since been used outside stadiums in Qatar. Sources list Katara Plaza, described as the country's first open-air air-conditioned commercial plaza, a cooled walkway in Aspire Park that uses solar panels, a commercial greenhouse and cow barns. Ghani has said he hopes other countries with hot climates will adopt the technology.
