The name “solar furnace,” translates in Latin to heliocaminus. A heliocaminus was simply a glass enclosed room meant to focus and heat the room, much like a modern sunroom. The principles behind a modern solar furnace hasn’t changed much from these sun rooms and “burning lenses.”
The world’s largest solar furnace is located in Font-Romeu-Odeillo-Via, a commune in the sunny Pyrenees mountains on the French-Spanish border. The furnace consists of a field of 10,000 mirrors, which bounce the sun’s rays onto a large concave mirror. The mirror focuses the enormous amount of sunlight onto an area roughly the size of a cooking pot, which reaches temperatures above 3,000 °C or 5,430 degrees Fahrenheit. The solar furnace itself isn’t exactly new. The first modern solar furnace was built in Mont Louis, in 1949 by professor Félix Trombe, and the current one was constructed in 1970. However the solar furnace continues to generate a beam of focused sunlight as powerful today as it was 3,000 years ago. At 54 m (177 ft) tall and 48 m (157 ft) wide, it is the world’s largest solar furnace.
It is used for several purposes, including melting steel, generating electricity via a steam turbine, making hydrogen fuels, testing re-entry materials for space vehicles, and performing high-temperature metallurgic experiments.