A solar furnace is a structure that uses concentrated solar power to produce high temperatures, usually for industry. Parabolic mirrors or heliostats concentrate

light Light, visible light, or visible radiation is electromagnetic radiation that can be visual perception, perceived by the human eye. Visible light spans the visible spectrum and is usually defined as having wavelengths in the range of 400– ...

( Insolation) onto a focal point. The temperature at the focal point may reach , and this heat can be used to generate

electricity Electricity is the set of physical phenomena associated with the presence and motion of matter possessing an electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by Maxwel ...

, melt

steel Steel is an alloy of iron and carbon that demonstrates improved mechanical properties compared to the pure form of iron. Due to steel's high Young's modulus, elastic modulus, Yield (engineering), yield strength, Fracture, fracture strength a ...

, make hydrogen fuel or nanomaterials. The largest solar furnace is at Odeillo in the Pyrénées-Orientales in

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

, opened in 1970. It employs an array of plane mirrors to gather sunlight, reflecting it onto a larger curved mirror.

History

The

ancient Greek Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

term ''heliocaminus'' means "solar furnace" and refers to a

glass Glass is an amorphous (non-crystalline solid, non-crystalline) solid. Because it is often transparency and translucency, transparent and chemically inert, glass has found widespread practical, technological, and decorative use in window pane ...

-enclosed sunroom intentionally designed to become hotter than the outside air temperature. 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. 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. 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.

Uses

The rays are focused onto an area the size of a cooking pot and can reach , depending on the process installed; for example: * about 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 * about to produce hydrogen by cracking methane molecules * up to to test materials for extreme environment such as nuclear reactors or space vehicle atmospheric reentry * up to to produce nanomaterials by solar induced sublimation and controlled cooling, such as

carbon nanotube A carbon nanotube (CNT) is a tube made of carbon with a diameter in the nanometre range ( nanoscale). They are one of the allotropes of carbon. Two broad classes of carbon nanotubes are recognized: * ''Single-walled carbon nanotubes'' (''S ...

s or zinc nanoparticles It has been suggested that solar furnaces could be used in

space Space is a three-dimensional continuum containing positions and directions. In classical physics, physical space is often conceived in three linear dimensions. Modern physicists usually consider it, with time, to be part of a boundless ...

to provide energy for manufacturing purposes. Their reliance on sunny weather is a limiting factor as a source of

renewable energy Renewable energy (also called green energy) is energy made from renewable resource, renewable natural resources that are replenished on a human lifetime, human timescale. The most widely used renewable energy types are solar energy, wind pow ...

Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...

but could be tied to thermal energy storage systems for energy production through these periods and into the night.

Smaller-scale devices

The solar furnace principle is being used to make inexpensive solar cookers and solar-powered barbecues, and for solar water

pasteurization In food processing, pasteurization (American and British English spelling differences#-ise, -ize (-isation, -ization), also pasteurisation) is a process of food preservation in which packaged foods (e.g., milk and fruit juices) are treated wi ...

. A prototype Scheffler reflector is being constructed in

India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...

for use in a solar

crematorium A crematorium, crematory or cremation center is a venue for the cremation of the Death, dead. Modern crematoria contain at least one cremator (also known as a crematory, retort or cremation chamber), a purpose-built furnace. In some countries a ...

. This 50 m² reflector will generate temperatures of and save 200–300 kg of firewood used per cremation.

References

External links

Article about the Odeillo and Mont Louis solar furnacesHochflussdichte Sonnenofen des DLR, KölnBBC News article about the solar power station serving Seville, Spain
{{Solar energy Industrial furnaces Solar thermal energy Heaters Industrial processes

History

Uses

Smaller-scale devices

See also

References

External links