SUSTAINABLE LIGHTING | HALOGEN
Halogens are Incandescent Lamps where the filament envelope is filled with a gas from the Halogen Family (Chlorine, Bromine, Fluorine, Iodine) thus enabling it to produce a larger amount of light and have a significantly longer life, since the halogen enables the tungsten vapour to recondense back on the filament. As a result, halogens are twice as efficient and have twice the lifetime of Incandescent Bulbs.
Halogen lamp produces light with higher luminous efficacy and color temperature. The small size of halogen lamp permits its use in compact optical systems for projectors and illumination. Standard and halogen incandescent bulbs are much less efficient than LED and compact fluorescent lamps, and have been banned in many places because of this.
As an Architect, I have described the advantages and disadvantages of sodium vapour lamps in Green buildings, under the following headings:
What are the advantages of Halogen lamps in green buildings?
What are the disadvantages of Halogen lamps in green buildings
ADVANTAGES OF HALOGENS IN GREEN BUILDINGS:
Availability and Cost: They are easily available and do not cost much – Rs50 to Rs 300, depending on the optics, colour and filters.
Variety: In the dichroic version, they are available in different colour temperatures and beam angles which make them an ideal choice for lighting ART and residential Interiors.
Color rendering: They have perfect colour rendering (Ra-100) that causes object colours to appear almost the same as in natural daylight.
Control: They can be dimmed easily, by simply varying the input voltage.
DISADVANTAGES OF HALOGENS IN GREEN BUILDINGS:
Luminous Efficacy: The Luminous Efficacy is quite low- at best around 30 lumens per watt.
Life: The Lifetime is also quite low compared to other lamps – 2000 to 4000 hours.
Because of the poor efficiency they cannot be considered energy efficient light sources. Hence there is the fear that they may become a casualty soon. I hope lighting companies continue their efforts to make these halogens more efficient, so that they can be used for their unique advantages.
Related Topics:
- Green Buildings Lighting | Incandescent Lamps
- Green Buildings Lighting | Compact Fluorescent Lamps
- Green Buildings Lighting | Fluorescent Tube Light
- Green Buildings Lighting | Metal Halides
- Green Buildings Lighting | Sodium Vapour Lamp
- Green Buildings Lighting | LED
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