Editing 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|thumb|right|400px|The [[Odeillo solar furnace|solar furnace at Odeillo]] 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 mirror]]s or [[heliostat]]s concentrate [[light]] ([[Insolation]]) onto a [[focus (optics)|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 solar furnace|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.<ref>{{Cite web |url=http://www.eng-forum.com/articles/Glossaries/Architecture_Roman.htm |title=MEEF Roman Architectural Glossary<!-- Bot generated title --> |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 }}</ref>

Legendary accounts of the [[Siege of Syracuse (213–212 BC)]] tell of [[Archimedes' heat ray]], a set of burnished brass mirrors or [[burning glass]]es 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>[https://patents.google.com/patent/US683088A/en 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>[http://www.promes.cnrs.fr/ Odeillo Solar Furnace official website], retrieved 12 July 2007</ref>

The [[Odeillo solar furnace|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&nbsp;°C.

[[Solar furnace of Uzbekistan|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>[http://englishrussia.com/2012/01/25/the-solar-furnace-of-uzbekistan/#more-88701 English Russia's post about the Uzbekistan Soviet Solar Furnace]</ref>

== 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 (solar power plant)|Themis plant]] with the Pegase project<ref>{{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 }}</ref>
* about {{convert|1400|C|F}} to produce hydrogen by cracking methane molecules<ref>[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 }}</ref>
* 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 (chemistry)|sublimation]] and controlled cooling, such as [[carbon nanotube]]s<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 [[nanoparticle]]s<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 manufacturing#Manufacturing|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|thumb|[[Paella]] being cooked with a solar cooker]]
The solar furnace principle is being used to make inexpensive [[solar cooker]]s and solar-powered [[barbecue]]s, and for solar water [[pasteurization]].<ref>{{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}}</ref><ref>[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 }}.</ref> A prototype [[Parabolic reflector#Scheffler reflector|Scheffler reflector]] is being constructed in [[India]] for use in a solar [[crematorium]]. This 50&nbsp;m<sup>2</sup> reflector will generate temperatures of {{convert|700|C|F}} and   save   200–300&nbsp;kg of firewood used per cremation.<ref>{{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}}</ref>

== See also ==
* [[Solar power tower]]
* [[Solar thermal energy]]
* [[Solar thermal collector]]
* [[Solar furnace of Uzbekistan]]

==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}}

[[Category:Industrial furnaces]]
[[Category:Solar thermal energy]]
[[Category:Heaters]]
[[Category:Industrial processes]]