ENVE 4105 Lecture Notes - Lecture 7: Luminous Flux, Solar Gain, Luminous Intensity
19 Jan 2016
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Document Summary
Nearly all power consumed by lamps is covered to heat. Heat either needs to be removed using air conditioning (or passively) or. But, we do not want to heat our buildings using lighting. Incandescent, compact fluorescent lamp (cfl), light-emitting diode (led) Efficient bulbs emit more light at visible wavelengths. Input energy to light bulb (watts), light bulb emits energy (lumens) Stay in ratio of highest to lowest. The time rate of light leaving a light source (independent of direction) Basically putting power into a lamp and getting lumens out. Analogy: the water flow rate out of a shower head. Efficiency of a luminaire is called efficacy. Examples of luminous efficacy (lm/w) (low to high) The amount of light that hits a surface. Key design metric and tells us whether the level of lighting is acceptable. Analogy: rate that a bathtub under a shower head fills up.
