Lighting and Daylighting照明和采光.doc

Lighting and Daylighting Lighting is an essential element of any building. Proper lighting improves the aesthetics of indoor spaces and provides illumination for tasks and activities. An efficient lighting strategy, including natural daylighting, can provide proper levels of illumination and reduce energy costs. Achieving these benefits requires integration of natural and artificial lighting sources early in the building design process.Lighting technologies include: Lamps—lighting sources, like fluorescent and incandescent light bulbs, and solid-state lighting. Ballasts—used with electric-discharge lamps such as fluorescent lamps, ballasts transform and control electrical power to the light. Luminaries (Fixtures)—complete lighting units that contain the bulbs and, if necessary, the ballasts. Lighting Controls—devices such as timers and sensors that can save energy by turning lights off when not needed. Daylighting—the use of natural light in a building. DOE conducts research and development on solid-state lighting. Learn more. Lamps Lamps—commonly called lightbulbs—produce light. When comparing lamps, it is important to understand the following performance characteristics: Color Rendering Index (CRI)—a measurement of a light sources accuracy in rendering different colors when compared to a reference light source with the same correlated color temperature. The highest attainable CRI is 100. Lamps with CRIs above 70 are typically used in office and living environments. Lamp types include: Incandescent Lamps Fluorescent Lamps Compact Fluorescent Lamps High Intensity Discharge Lamps Low Pressure Sodium Lamps Solid-State Lighting (LEDs and OLEDs) Incandescent Lamps A standard incandescent lamp consists of a fairly large, thin, frosted glass envelope. Inside the glass is an inert gas such as argon and/or nitrogen. At the center of the lamp is a tungsten filament. Electricity heats the filament. The heated tungsten emits visible light in a process called incandesce