Solar furnace
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A solar furnace is a structure that uses concentrated solar power to produce high temperatures, usually for industry. Parabolic mirrors or heliostats concentrate light (Insolation) onto a focal point. The temperature at the focal point may reach Template:Convert, and this heat can be used to generate electricity, melt steel, make hydrogen fuel or nanomaterials.
The largest solar furnace is at Odeillo in the Pyrénées-Orientales in France, opened in 1970. It employs an array of plane mirrors to gather sunlight, reflecting it onto a larger curved mirror.
HistoryEdit
The ancient Greek / Latin term heliocaminus means "solar furnace" and refers to a glass-enclosed sunroom intentionally designed to become hotter than the outside air temperature.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
Legendary accounts of the Siege of Syracuse (213–212 BC) tell of Archimedes' heat ray, a set of burnished brass mirrors or burning glasses supposedly used to ignite attacking ships, though modern historians doubt its veracity.
On 24 September 1901, Knut C. Wideen was granted a patent for a "System for collecting and utilizing solar heat", which included a solar furnace.<ref>U.S. Patent 683,088</ref>
The first modern solar furnace is believed to have been built in France in 1949 by Professor Félix Trombe. The device, the Mont-Louis Solar Furnace is still in place at Mont-Louis. The Pyrenees were chosen as the site because the area experiences clear skies up to 300 days a year.<ref>Odeillo Solar Furnace official website, retrieved 12 July 2007</ref>
The Odeillo Solar Furnace is a larger and more powerful solar furnace. It was built between 1962 and 1968, and started operating in 1969. It's currently the most powerful, based on an achievable temperature of 3500 °C.
The Solar Furnace of Uzbekistan was built in Uzbekistan and opened in 1981 as a part of a Soviet Union "Sun" Complex Research Facility, being the world largest concentrator.<ref>English Russia's post about the Uzbekistan Soviet Solar Furnace</ref>
UsesEdit
The rays are focused onto an area the size of a cooking pot and can reach Template:Convert, depending on the process installed; for example:
- about Template:Convert for metallic receivers producing hot air for the next-generation solar towers as it will be tested at the Themis plant with the Pegase project<ref>{{#invoke:citation/CS1|citation
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- about Template:Convert to produce hydrogen by cracking methane molecules<ref>SOLHYCARB, EU funded project, ETHZ official page Template:Webarchive</ref>
- up to Template:Convert to test materials for extreme environment such as nuclear reactors or space vehicle atmospheric reentry
- up to Template:Convert to produce nanomaterials by solar induced sublimation and controlled cooling, such as carbon nanotubes<ref>Flamant G., Luxembourg D., Robert J.F., Laplaze D., Optimizing fullerene synthesis in a 50 kW solar reactor, (2004) Solar Energy, 77 (1), pp. 73-80.</ref> or zinc nanoparticles<ref>T. Ait Ahcene, C. Monty, J. Kouam, A. Thorel, G. Petot-Ervas, A. Djemel, Preparation by solar physical vapor deposition (SPVD) and nanostructural study of pure and Bi doped ZnO nanopowders, Journal of the European Ceramic Society, Volume 27, Issue 12, 2007, Pages 3413-342</ref>
It has been suggested that solar furnaces could be used in space to provide energy for manufacturing purposes.
Their reliance on sunny weather is a limiting factor as a source of renewable energy on Earth but could be tied to thermal energy storage systems for energy production through these periods and into the night.
Smaller-scale devicesEdit
The solar furnace principle is being used to make inexpensive solar cookers and solar-powered barbecues, and for solar water pasteurization.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>US patent for solar barbecue granted in 1992 Template:Webarchive.</ref> A prototype Scheffler reflector is being constructed in India for use in a solar crematorium. This 50 m2 reflector will generate temperatures of Template:Convert and save 200–300 kg of firewood used per cremation.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>