The world's largest solar energy facility, built with Austrian technology, has opened in Saudi Arabia and will provide Riyad's Princess Noura Bint Abdulrahman University with warm water.

The facility, built by Austrian firms GREENoneTEC and AEE Intec, consists of 36,000 square metres (387,500 square feet) of solar panels and cost 3.6 million euros ($4.7 million).

After a six-month trial period that began in late 2011, the facility became operational this week, its makers said.

Almost twice as large as the biggest solar thermal facility so far in Denmark, the new system also uses special material and structures to withstand sandstorms.