Overnight at the end of September the temperature in Qatar is 35 degrees Celsius outside the newly built South Stadium to host the 2022 FIFA World Cup, but the temperature inside is 21 degrees Celsius.
Qatar said it had designed air conditioning systems that would make it easier to use outdoor playgrounds even in the hot summer, when temperatures exceed 40 degrees Celsius.
The World Cup was set for November and December to avoid extreme heat in Doha, but Qatar has decided to keep plans to adapt the stadiums for future use throughout the year.
The South Stadium was inaugurated in May, and new cooling systems were used.
"You are in a small bubble whose temperature is controlled," said Saud Abdul Ghani, a professor of mechanical engineering at Qatar University, who headed the design team, waving a thermometer to show a 14-degree temperature drop.
This is the first of seven stadiums to receive the World Cup, and the rest of the stadiums are due to be completed by the end of 2020.Khalifa International Stadium was renovated and opened in 2017.
The ball-size nozzles are pumped into the stadium pumping cold air, pipes down benches, to keep temperatures between 24 and 26 degrees in the stands, and the temperature is adjusted from the control room.
Officials of the World Heritage and Projects Committee, which is responsible for organizing the World Cup, said the country has spent $ 6.5 billion to $ 7 billion for major stadiums and training pitches.
The director of the South Stadium project (Al Wakra) Thani Khalifa agriculture that the cooling system has increased the cost of construction doubled or tripled by between six and seven thousand dollars per seat, pointing out that the cost of construction of each stadium ranges between 240 and 280 million dollars.