Electric Light Sources

Electric Light Sources You likely won’t be able to illuminate a space through daylight alone all the time, so you’ll have to learn to efficient artificial light design. Light sources are the different kinds of lamps, bulbs, or other devices used to create artificial light. The choice of light source is v ery important, both for visual comfort and for energ y efficiency. Roughly 1/3 of an average US commercial building' s energy use is lighting . Artificial light sources are measured not only by their visual comfort characteristics (brightness, color temperature, color rendering index, and light distribution), but also their efficacy--that is, their effectiveness at converting electricity into light. Lighting Efficiency Common Light Sources Selecting a Lamp Lighting Efficiency The energy efficiency of artificial lights are measured b y "luminous efficacy", the ratio of luminous flux coming out (in Lumens) to electricity and/or heat going in (in Watts). Energy that does not emerge as light emerges as h eat. Note that lighting efficiency is a function of b oth light source itselfand the fixture housing it. Category Type Combustion candle gas mantle Incandescent tungsten incandescent tungsten glass halogen Fluorescent Compact fluorescent T8 tube T5 tube Light-emitting diode LED screw base lamp (120 V) Gas discharge metal halide low pressure sodium Luminous efficacy of various light sources ( from Wikipedia )

Electric Light Sources

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