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2007-07-23 Rev. 2008-05-06, -11-07, -11-29, 2009-06-17, -12-11
This isn't called Lighting Glass because somewhere down there I
want to explore using natural light with glass
and make some points about
illumination.
Like here:
Glass & Light Center
Incandescent |
Fluorescent CFB |
Halogen |
LED |
Candles |
Arc |
Area Lighting |
Incandescent |
Fluorescent |
Halogen Technically, quartz-halogen. The quartz is required because the tungsten filament is run at a very high temperature and it heats the tube around it. Halogen gas (chlorine, bromine, etc.) participates in a chemical reaction where the titanium boiled off the filament and deposited on the quartz is recycled back to the filament. Thus, a filament that would burn out quickly and blacken the bulb without the reaction has a reasonable life. Halogen bulbs have a distinctive bright white light and bulbs are typically twice as efficient and slightly longer lived than plain incandescent. Standard voltage halogen bulbs have the quartz tube inside a glass shell that is heavier glass so if the tube breaks the very hot quartz will not be a risk of fire or injury. Halogen bulbs are available in miniature low voltage (12 volt) units commonly seen in store displays which allow fixtures clamped to exposed metal rods and which require a small switching power supply - a 50 watt 12 volt M16 spot/flood requires just over 4 amps of current. As it says on the package, touching the quartz with bare fingers can shorten the life of the bulb. 2009-06-17 |
LED The latest in white lighting is newly available high intensity white Light Emitting Diodes (LED's) which produce light by electron stimulation - sort of like a laser. In the past, LED's were always colored and generally of low brightness. High intensity color came first and now by combining colors within the unit, bright white units are available as for flashlights and related products. LED's run cool and have a long life. As of spring 2008 small devices with batteries and base or solar chargers have come on the market to replace or act as candle like lighting. As of the fall of 2009, screw in units to replace ornamental lights are becoming available, but made of a couple of dozen LED's and over $10 a bulb, they are not very romantic like the candle shapes they replace. 32 lumens per watt 2009-12-11 |
Candles and Oil Lamps/Candles Arc |
Area Lighting Incandescent, fluorescent, and halogen bulbs are used for area lighting as plain bulbs and in flood reflector lights. At least two kinds of bulbs exist that are only suitable for area lighting because of their colors and a variation of one is only used for area lighting because it is so bulky and bright. Each of these bulbs places a glass capsule containing a vapor light source in the center of a bulky glass bulb and all require a ballast in the lamp fixture to start and maintain the light. The required fixtures with a bulb cost $30-90 and up. They are the most efficient light sources with limitations discussed below, but all take dozens of seconds to minutes to come up to brightness and thus are not suitable to motion control or photocell activation by people. Most exterior are turned on sunset to sunrise or by timers. High Pressure Sodium creates an arc in sodium vapor that causes the plasma to glow brightly with the yellow color of sodium that glassworkers wear didymium (purple) glasses to see through. Unlike a spectrum of colors for white light, the light is emitted at very narrow frequencies in the yellow range. These are the yellow lights of parking lot and street lighting. The light is very efficient* and the bulbs very long lived but the narrow colors mean that people's pink/red lips look black (no red in the light to reflect) and other colors can't be judged accurately. As with all yellow bulbs, bugs are not attracted. I have one in my backyard. Emission lines Narrow peaks Mercury Vapor and Metal Halide bulbs put a small amount of mercury in the capsule. Mercury vapor bulbs give off a strong blue white light that is harsh on people's skin color and "feels" cool - not warm and friendly. These are seen in parking lots as more polite to faces or moonlike than sodium, but car colors may be hard to pick out. Metal Halide bulbs put a mix of other volatile metals with chlorine, bromine or iodine (halides) in the capsule. Mercury vapor fixture making and sale was banned in U.S. as of 2008-01-01 These are more costly but also more efficient than Mercury Vapor lights, but the white light is much more pleasant. These are used for down lighting in very large spaces like gymnasiums and factories. The fixtures and bulbs are more costly so these tend to be used in larger sizes and a single bulb would overwhelm a low ceilinged space. 2008-11-06 |
Bulb Type | Life | Watts | Lumens | Lumens/Watt | Productl Cost* | 10,000 Hours* |
High Pressure Sodium 35W 1 | 16,000 | 35W | 2250 | 64 | ||
High Pressure Sodium 70W 5 | 25,000 | 75W | 10?000 | 80 | ||
Mercury Vapor 175W4 | 175W | 7000 3700K 45 CRI | 31.21 | |||
Metal Halide 70 or 100W 6 | 24000 | 100W | 4200K 92 CRI | |||
LED Bright White2 | 115-180 | |||||
Compact Fluorescent3 | 10,000 | 14W | 900 | 64 | 1.72 | 32.50 |
Tungsten Halogen3 | 100W | 1670 | 16.7 | |||
Incandescent 3 | 800 | 100W | 1380 | 13.8 | .75 | 1265.63 |
Fluorescent | Typical | 35W 4' tube | 3000 | 100 | 10.50 |
* Without labor - fixture and bulb(s) for 10,000 hours (est. 5 years) @ 13.5 cents per kwh (Texas cost) |
1 http://www.iladesignteam.com/lumen_ratings.htm |
2 http://en.wikipedia.org/wiki/Light_emitting_diode |
3 http://en.wikipedia.org/wiki/Luminous_efficiency#Lighting_efficiency |
4 manufacture banned 2008-01-01 see metal halide |
5 http://www.idealtruevalue.com/servlet/the-174301/E70H-LIGHT-SECURITY-HPS/Detail |
6
http://mercuryvaporlight.com/ http://www.castlewholesalers.com/REGENT-ALEA70MH-Metal-Halide-Safety-Security-Light-70W.html |
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