Light emission incandescence vs. luminescence Lamp types Incandescent (classic, halogen) Discharge (fluorescent tubes) Electrodeless (induction-based) 8 Natural light 7 Low pressure sodium 6 High pressure sodium 5 Mercury vapor 4 Fluorescence 3 Metal halide 2 Halogen lm/w 200 180 160 140 120 100 80 60 40 20 0 1 2 } Incandescent lamps 3 4 5 6 7 8 } } Discharge lamps Natural light 1 Classic incandescent Figure by MIT OCW.
Incandescent lamps (color T = 2500 K) Classic incandescence 15 to 500 W 6 to 17 lm/w
Incandescent lamps (color T = 2500 K) Classic incandescence Halogen incandescence 25 to 2000 W 10 to 22 lm/w
Incandescent lamps Discharge lamps Visible Light Fluorescent tubes Lamp Bulb Wall 18, 36 or 58 W 53 to 89 lm/w Point of Impact Ultraviolet Radiation Phosphor Crystals color T between 3000 - and 6000 K poor to pretty good color rendering Path of Conduction Electron + Electron Cloud of Single Mercury Atom - After Impact Valence Electron Figure by MIT OCW.
Incandescent lamps Discharge lamps Fluorescent tubes Compact fluorescents 3 to 23 W 33 to 65 lm/w 3000 to 3500 K pretty good color rendering
Incandescent lamps Discharge lamps Fluorescent tubes Compact fluorescents Metal halides 40 to 150 W for HQI, 250 to 3500 W for HQI-T 85 lm/w for HQI, 80 to 91 lm/w for HQI-T 3500 to 4000 K for HQI, 3000 K for HQI-T pretty good color rendering for both
Incandescent lamps Discharge lamps Fluorescent tubes Compact fluorescents Metal halides Mercury vapor 50 to 1000 W 35 to 60 lm/w 3000 K pretty good color rendering
Incandescent lamps Discharge lamps Fluorescent tubes Compact fluorescents Metal halides Mercury vapor Sodium High pressure: 50-1000 W, 70-130 lm/w, 3000 K, poor to fair color T
Incandescent lamps Discharge lamps Fluorescent tubes Compact fluorescents Metal halides Mercury vapor Sodium High pressure: 50-1000 W, 70-130 lm/w, 3000 K, poor to fair color T Low pressure: 18-185 W, 100-200 lm/w, no color rendering (one λ)
Incandescent lamps Discharge lamps Induction lamps (electrodeless) EM induction discharge Visible light 70 to 150 W 65 lm/w 3000 K Molecule of metallic vapor UV Fluorescent powder pretty good color rendering Induction coil Figure by MIT OCW.
Kinds of luminaires point sources central / axial symmetry vs. linear sources transverse symmetry longitudinal symmetry Figure by MIT OCW.
Kinds of luminaires Direct extensive Direct intensive Indirect Direct indirect Asymmetrical
Optics and Reflectors for control emitted flux distribution None Louver No cover down + Diffuser up Diffuser up + Down Diffuser up + Louvres down No cover up and down No cover up + Diffuser down No cover up + Louvres down Diffuser Figures by MIT OCW.
Catalog information Light Output Ratio (LOR) Glare control (based on various glare or visual comfort metrics) Light intensity distribution (LID) Variants and others illuminance maps at given distance coefficients of utilization luminances, lumens by zone
Intensity distributions IES 01 IES12 IES 06 IES 15 IES 02
Intensity distributions Which luminaire should I choose to illuminate my desk efficiently? 1 m 90 60 cm 30 1 m 2 m 40 80 cm
Intensity distributions Which of these luminaires should I choose to optimize my desk s illumination? 235 255 270 285 305 215 345 195 345 180 180 150 120 90 60 30 0 165 15 145 35 125 105 90 75 55 235 255 270 285 305 215 325 180 195 200 160 120 80 40 0 345 0 165 15 145 35 125 105 90 75 55 Figures by MIT OCW.
Intensity distributions Which of these luminaires should I choose to optimize my desk s illumination? 1 m 90 60 cm 175 Cd 45 60 cm 70 Cd 70 50 30 1 m 90 110 Cd 140 Cd 2 m 40 1 m 2 m 40 1 m 80 cm 80 cm
Coefficients of utilization (CU): Lumen method Objective: calculate average illuminance Ē workplane = total Φ wp / A wp CU definition: % of lamp lumens reaching workplane Ē workplane = (Nb luminaires) x (Lumens per luminaire) x CU x LLF / A workplane hcc Ceiling ρceiling Ceiling cavity hrc ρwall Luminaires Room cavity Workplane hfc Floor ρfloor Floor cavity Figure by MIT OCW.
Efficiency of a lighting installation lighting equipment used lighting installation design electric lighting use
Reading relevant to lecture topics: "Heating Cooling Lighting" by Lechner: Chap 14 "IESNA Lighting Handbook" (9th Ed.): Chap 6-7 + Chap 9 "Introduction to Architectural Science " by Szokolay: 2.5