quartz-iodine bulbs?

reading a book published in 1977 called '30 energy-efficient houses' and it mentions a form of lighting called 'quartz-iodine'. it says that this type of wide area lighting works well out-doors and is very efficient. anyone heard of this? what is it? how effiecient?

I don't know but maybe it's related (Or the same thing) as those bulbs in parking lots everywhere. I think they're called sodium something, the ones the cast an awful yellow light. The ones that are being replaced everywhere with whiter lighting because the yellow (exp. where there are parking lots lit by them alongside a major roadway) drives people nuts?

Originally posted by papasan:
reading a book published in 1977 called '30 energy-efficient houses' and it mentions a form of lighting called 'quartz-iodine'. it says that this type of wide area lighting works well out-doors and is very efficient. anyone heard of this? what is it? how effiecient?

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<font size="2" face="Verdana, Arial">These are simply halogen incandescent lamps in which the envelope is fabricated from quartz rather than more conventional glasses and the choice of halogen is iodine. Most halogen lamps do not use quartz for the envelope and may use either iodine or bromine as the halogen. Despite this, you often hear the term quartz iodine being [incorrectly] used interchangeably with halogen.

Another halogen gas that is used in quartz incandescent bulbs is Xenon and this leads to even more confusion since Xenon is the fill used in HID - high intensity discharge lamps which are not incandescent and don't use a filament. Many packages label Quartz incandescent lights incorrectly as HID or simply as Xenon. Xenon is the most expensive of the halogen fill gases and many bulbs labeled Xenon have just trace amounts.

Originally posted by Bob Snow:
Another halogen gas that is used in quartz incandescent bulbs is Xenon and this leads to even more confusion since Xenon is the fill used in HID - high intensity discharge lamps which are not incandescent and don't use a filament. Many packages label Quartz incandescent lights incorrectly as HID or simply as Xenon. Xenon is the most expensive of the halogen fill gases and many bulbs labeled Xenon have just trace amounts.

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<font size="2" face="Verdana, Arial">Bob: Check the periodic table. Xenon is a noble gas, not a halogen.

'Halogen' lamps are gas filled tungsten filament lamps in which a portion of the gas fill is from the halogen family, eg. Bromine, Iodine. The balance of the fill gas is some inert gas, eg Argon, Krypton, Xenon.

Xenon is the most expensive of the inert gases which may be used in lamps. Because atoms of Xenon are heavier than those of the other inert gases, there is less thermal conduction from the filament, less evaporation of Tungsten, and possibly other benefits. (I guess one could use Radon, and the lamp would be both more expensive and more efficient, but there are other issues...)

-Jon