Talk:Solar furnace

4000 degrees C[edit]

Would like to know how these numbers are arrived at. Thermodynamics limits the temperature at 5800K, after which a perfect absorber would emit more radiation than it collected, but that is assuming that sunlight reaching the earth is a perfect blackbody spectrum, which of course it is not.

The 3,000 degrees figure comes from this link [1]. I am not an expert on the solar furnace, but perhaps the article should not give both 4,000 and 3,000 degrees due to the contradiction. The Odeillo solar furnace is also rated at up to 1000kW.--Ianmacm 18:14, 2 July 2007 (UTC)[reply]

If the sun was in contact with the absorber, the limiting temperature would be the surface temperature of the sun, 5800K, but it is the coherence of light that sets a limit, not thermodynamics. Without a reference, I'm deleting the statement. 199.125.109.134 (talk) 15:00, 25 September 2008 (UTC)[reply]

Some answers: thermodynamics says that the solar furnace can not achieve higher temperature than its source, here sun's outer atmosphere somewhere around 5700 K. Reality lowers this figure so far to about 4,000 °C (7,230 °F) as the optical system can not be made perfect (micro & macro defects of the mirors, mechanical deformation, sun tracking errors, dust, atmosphere absorption… without particular order).

With the same input thermal power and density power (eg about 1000 kW and 10000 concentration ratio for Odeillo's big furnace ^[1]), different thermal equilibrium can be achieved, depending how much energy is used to rise temperature and how much is used in the process (melting, vaporization , cracking…).

With good solar furnaces, ie with good optics and thus high density power, melting of tungsten can be achieved (3,422 °C (6,192 °F)), or water thermolysis (despite not absorbing sunlight very well as being transparent and needing quite some energy to break the molecule at 3,250 °C (5,880 °F)^[2].

References

Father Himalaya AKA Padre Himalaya[edit]

The first modern solar furnace is believed to have been built in France, but not in 1949 by Professor Félix Trombe. In 1900, Father Himalaya [2][3] built in Sorède, Pyrenees of France the first solar furnace, and is still possible to see the remains on site [4].
[[Image:http://lcbuevora.naturlink.pt/uploads/%7B94380B3F-DF6A-4157-9F81-956A3A230949%7D.jpg]]
Sonja Hortela 02:11, 5 September 2007 (UTC)Sonja Hortela[reply]

Burning ships[edit]

It strikes me that it would not be necessary to burn wood (-en ships) for Archimedes' trick to have worked.

Aiming the beams at humans aboard the ship would have burnt them severely, and given the impression that they could burn ships, even if they could not. Attackers would then have ceased getting closer.
And also possible, if less likely, the beams might have burnt sail cloth or other material on the boat, thus setting the vessel alight.

Tabby 18:39, 15 September 2007 (UTC)[reply]

The deletion of "heliocaminus" - Well-documented origin of the term "solar furnace"[edit]

The edit that deleted this material said it was "off topic." I very strongly disagree.

The article talks about the very-off-topic "Second Punic War", wherein a solar furnace was NOT used, but you deleted the History of the very source of the ancient word "heliocaminus"[5] FACT, which literally means "solar furnace." How could that possibly be considered off topic by anyone ? ? ?

I request consensus that the well-cited deleted material be immediately restored, or give me permission to replace it.

BC versus BCE[edit]

In modern political correctness, BCE should always be used for non-religious references, instead of the obsolete BC, which is meaningful to a minority of the world. My edit was deleted. Please see the article on BCE, and then restore the change. How could anyone argue against that?

That article does not state whether BC/AD or BCE/CE is to be used on Wikipedia. If I missed where that is stated, please give a more direct reference as the article is rather long. The article actually presents the BCE/CE system as "alternative" and gives several arguments against its use, so you need to bolster your argument further. 184.100.0.99 (talk) 00:24, 13 August 2014 (UTC)[reply]

Why was the properly-cited reference to "solar cooker" removed ?[edit]

If "barbeque" is on topic, than solar cooker most certainly is.

Why delete the existing citations to barbeque ?

- Very curious inconsistent editing.

External links modified (January 2018)[edit]

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[1] ttp://www.promes.cnrs.fr/MOYENS/Concentrateurs/eng-MWSF.htm

[2] ttp://www.hionsolar.com/n-hion96.htm

[1]

[2]