Solar cooling: Plans for air-conditioned stadiums in Qatar
When Qatar won the bid to host the 2022 football World Cup in December 2010, it came as a surprise. One of the major causes of scepticism was the average summer temperatures of over 40°C with recent peaks at 50°C. But central to Qatar's bid was a revolutionary cooling system that will use solar technology to provide zero-carbon cooling of the 12 stadiums involved. Solar thermal collectors and photovoltaic panels on the outside and rooftops of the stadiums will heat water to 200°C, under high pressure; lithium-bromide absorption chillers will then create a strong vacuum which sets up the pressure differences required for the expansion and evaporation of vapour, before the solar heat drives the vapour out of the lithium bromide solution again, allowing for a continuous refrigeration cycle to chill water that then is claimed to cool the air blown through the stadium in order to keep the pitch and seating areas below 27°C. In the latter, air at 18°C will be blown around the spectator ankle zone and from the back and neck areas of the seats. The same system will be used to cool the competing teams' training facilities and the panels will also supply electricity to Qatar's national grid, making this first-in-its-kind cooling system carbon neutral.