solar furnace
{{Short description|Focal point for concentrated sunlight; contains working fluid to be heated}}
{{About||the cooking apparatus|Solar cooker|electricity generation|Solar power tower}}
File:Four solaire 001.jpg in the Pyrénées-Orientales in France can reach temperatures of {{convert|3500|C|F}}.]]
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 {{convert|3500|C|F}}, 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.
History
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.{{Cite web |url=http://www.eng-forum.com/articles/Glossaries/Architecture_Roman.htm |title=MEEF Roman Architectural Glossary |access-date=2009-12-05 |archive-date=2017-06-12 |archive-url=https://web.archive.org/web/20170612121650/http://www.eng-forum.com/articles/Glossaries/Architecture_Roman.htm |url-status=dead }}
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.[https://patents.google.com/patent/US683088A/en U.S. Patent 683,088]
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.[http://www.promes.cnrs.fr/ Odeillo Solar Furnace official website], retrieved 12 July 2007
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.[http://englishrussia.com/2012/01/25/the-solar-furnace-of-uzbekistan/#more-88701 English Russia's post about the Uzbekistan Soviet Solar Furnace]
Uses
The rays are focused onto an area the size of a cooking pot and can reach {{convert|4000|C|F}}, depending on the process installed; for example:
- about {{convert|1000|C|F}} 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{{Cite web |url=http://www.promes.cnrs.fr/pegase/index.php |title=PEGASE project home page |access-date=2010-01-24 |archive-date=2017-12-01 |archive-url=https://web.archive.org/web/20171201081635/https://www.promes.cnrs.fr/pegase/index.php |url-status=dead }}
- about {{convert|1400|C|F}} to produce hydrogen by cracking methane molecules[http://www.pre.ethz.ch/research/projects/?id=solhycarb SOLHYCARB, EU funded project, ETHZ official page] {{webarchive|url=https://web.archive.org/web/20090313121601/http://www.pre.ethz.ch/research/projects/?id=solhycarb |date=2009-03-13 }}
- up to {{convert|2500|C|F}} to test materials for extreme environment such as nuclear reactors or space vehicle atmospheric reentry
- up to {{convert|3500|C|F}} to produce nanomaterials by solar induced sublimation and controlled cooling, such as carbon nanotubesFlamant 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. or zinc nanoparticlesT. 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
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 devices
File:Cuina solar paella.JPG being cooked with a solar cooker]]
The solar furnace principle is being used to make inexpensive solar cookers and solar-powered barbecues, and for solar water pasteurization.{{cite web |url=https://www.solarcookers.org/application/files/4715/5778/9440/SCI_How_to_Make_Use_and_Enjoy.pdf | publisher = Solar Cookers International | title = SOLAR COOKERS How to make, use, and enjoy | year = 2004}}[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=5090399.PN.&OS=PN/5090399&RS=PN/5090399 US patent for solar barbecue granted in 1992] {{Webarchive|url=https://web.archive.org/web/20171201082309/http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=/netahtml/PTO/srchnum.htm&r=1&f=G&l=50&s1=5090399.PN.&OS=PN/5090399&RS=PN/5090399 |date=2017-12-01 }}. A prototype Scheffler reflector is being constructed in India for use in a solar crematorium. This 50 m2 reflector will generate temperatures of {{convert|700|C|F}} and save 200–300 kg of firewood used per cremation.{{cite web
| title=Development Of A Solar Crematorium
| publisher=Solare Brüecke
| url=http://www.solare-bruecke.org/infoartikel/Papers_%20from_SCI_Conference_2006/22_wolfgang_scheffler.pdf
| access-date=2008-05-20}}
See also
References
{{Reflist}}
External links
- [http://www.anglophone-direct.com/Mont-Louis-Font-Romeu-Odeillo-Via Article about the Odeillo and Mont Louis solar furnaces]
- [https://web.archive.org/web/20090219020314/http://www.dlr.de/tt/desktopdefault.aspx/tabid-2881/4512_read-6629/ Hochflussdichte Sonnenofen des DLR, Köln]
- [https://web.archive.org/web/20070515143956/http://www.promes.cnrs.fr/TOUT-PUBLIC/Les-fours/lesfours1.htm Page including an animation of a solar furnace]
- [http://news.bbc.co.uk/1/hi/sci/tech/6616651.stm BBC News article about the solar power station serving Seville, Spain]
- [http://amasci.com/amateur/mirror.html Build a solar furnace]
{{Solar energy}}