Solar furnace

:"For the cooking apparatus see Solar cooker. For electricity generation see Solar updraft tower."

A solar furnace is a structure used to harness the rays of the sun in order to produce high temperatures, usually for industry. This is achieved using a curved mirror (or an array of mirrors) that acts as a parabolic reflector, concentrating light (Insolation) onto a focal point. The temperature at the focal point may reach convert|3000|C|F, and this heat can be used to generate electricity, melt steel, or make hydrogen fuel.

The term "solar furnace" has also evolved to refer to solar concentrator heating systems using parabolic mirrors or heliostats where convert|538|C|F is now commonly achieved. The largest solar furnace in the world is at Odeillo in the Pyrenees of France, opened in 1970. It employs an array of plane mirrors to gather the rays of light from the sun, reflecting them on to a larger curved mirror. The rays are then focused onto an area the size of a cooking pot and can reach convert|3000|C|F.

History

The ancient Greek / Latin term "heliocaminus" literally means "solar furnace" and refers to a glass-enclosed sunroom intentionally designed to become hotter than the outside air temperature. [ [http://www.eng-forum.com/articles/Glossaries/Architecture_Roman.htm MEEF Roman Architectural Glossary ] ]

During the Second Punic War (218 - 202 BCE), the Greek scientist Archimedes is said to have repelled the attacking Roman ships by setting them on fire with a "burning glass" that may have been an array of mirrors. An experiment to test this theory was carried out by a group at the Massachusetts Institute of Technology in 2005. It concluded that although the theory was sound for stationary objects, the mirrors would not likely have been able to concentrate sufficient solar energy to set a ship on fire under battle conditions. [ [http://web.mit.edu/2.009/www//experiments/deathray/10_ArchimedesResult.html 2.009 Product Engineering Processes: Archimedes ] ]

The first modern solar furnace is believed to have been built in France in 1949 by Professor Félix Trombe. It is still in place at Mont Louis, near Odeillo. The Pyrenees were chosen as the site for these furnaces due to sunny weather for up to 300 days a year. [http://www.promes.cnrs.fr/ Odeillo Solar Furnace official website, retrieved 12 July 2007]

Modern uses

The solar furnace principle is being used to make inexpensive solar cookers and solar-powered barbecues, and for solar water pasteurization. [ [http://www.solarcookers.org/basics/water.html Solar Cookers International (Solar Water Pasteurization ] ] [ [http://www.dailymail.co.uk/pages/live/articles/technology/technology.html?in_article_id=449500&in_page_id=1965 Coming to a garden near you - the solar-powered barbecue | the Daily Mail ] ] [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.] 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 displace 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
accessdate=2008-05-20]

It has been suggested that solar furnaces could be used in space to provide energy for manufacturing purposes. Their reliance on sunny weather may mean that they are unlikely to be used as a major source of renewable energy on Earth.

See also

* Solar power tower
* Nevada Solar One
* Solar One
* Themis
* Solar thermal energy
* Energy tower

References

External links

* [http://www.anglophone-direct.com/Mont-Louis-Font-Romeu-Odeillo-Via Article about the Odeillo and Mont Louis solar furnaces]
* [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]