1 / 20

Energy Efficient Lighting

Energy Efficient Lighting. Energy for Lighting. We spend about one-quarter of our electricity budget on lighting, or more than $37 billion annually

keithwilson
Download Presentation

Energy Efficient Lighting

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Energy Efficient Lighting

  2. Energy for Lighting • We spend about one-quarter of our electricity budget on lighting, or more than $37 billion annually • Technologies developed during the past 10 years can help us cut lighting costs 30% to 60% while enhancing lighting quality and reducing environmental impacts.

  3. Objectives • Lighting principles and definitions • Types of lighting and how each works • Energy-efficient lighting options, including daylighting, for new or retrofit applications.

  4. Lighting and Energy Savings • Lighting principles and definitions • Types of lighting and how each works • Energy-efficient lighting options, including day lighting, for new or retrofit applications.

  5. How lighting is measured? • The most common measure of light output (or luminous flux) is the lumen . All lamps are rated in lumens • The distribution of light on a horizontal surface is called its illumination. • Illumination is measured in footcandles. A footcandle of illumination is a lumen of light distributed over a 1-square-foot (0.09-square-meter) area

  6. How much light do we need? • The task(s) being performed (contrast, size, etc.) • Ambient • Task • Accent • The ages of the occupants • The importance of speed and accuracy

  7. Factors Affecting the Quantity of Lamps Required • Fixture efficiency • Lamp lumen output • The reflectance of surrounding surfaces • The effects of light losses from lamp lumen depreciation and dirt accumulation • Room size and shape • Availability of natural light (daylight)

  8. How Much Light? • In the past, spaces were designed for as much as 200 footcandles in places where 50 footcandles may not only be adequate, but superior. • Not only does over lighting waste energy, but it can also reduce lighting quality • 30 fc of ambient lighting for computer room • 50 fc for reading and writing

  9. Color Rendition Index • The ability to see colors properly is another aspect of lighting quality • The color rendering index (CRI) scale is used to compare the effect of a light source on the color appearance of its surroundings. A scale of 0 to 100 defines the CRI. • A higher CRI means better color rendering, or less color shift

  10. Types of Lighting • There are four basic types of lighting: • Incandescent, • Fluorescent, • High-intensity discharge, and • Low-pressure sodium

  11. Incandescent Light • Light is produced by a tiny coil of tungsten wire that glows when it is heated by an electrical current. • shortest lives • Inefficient Filament

  12. Types of Incandescent Bulbs • Standard incandescent • Most common yet the most inefficient • Larger wattage bulbs have a higher efficacy than smaller wattage bulbs • Tungsten halogen • It has a gas filling and an inner coating that reflect heat • Better energy efficiency than the standard A-type bulb • Reflector lamps • Reflector lamps (Type R) are designed to spread light over specific areas • floodlighting, spotlighting, and downlighting

  13. Fluorescent Bulbs • filled with an argon or argon-krypton gas and a small amount of mercury • coated on the inside with phosphors • equipped with an electrode at both ends 3 to 4 times as efficient as incandescent lighting • Fluorescent lamps provide light by the following process: • An electric discharge (current) is maintained between the electrodes through the mercury vapor and inert gas. • This current excites the mercury atoms, causing them to emit non-visible ultraviolet (UV)radiation. • This UV radiation is converted into visible light by the phosphors lining the tube

  14. Fluorescent Bulbs • Fluorescent lamps last about 10 times longer than incandescent bulbs • Fluorescent lights need ballasts (i.e., devices that control the electricity used by the unit) for starting and circuit protection

  15. Types of Fluorescents Compact fluorescent • Tube fluorescent

  16. CFLs • CFLs can replace incandescents that are roughly 3 to 4 times their wattage • They last 10 to 15 times as long. • Cost from 10 to 20 times more than comparable incandescent bulbs • One of the best energy efficiency investments available.

  17. High Intensity Discharge (HID) Lamp • High-intensity discharge (HID) lamps provide the highest efficacy and longest service life of any lighting type • mercury vapor • metal halide, and high-pressure sodium They also require ballasts, and they take a few seconds to produce light when first turned on because the ballast needs time to establish the electric arc

  18. Efficacy • This is the ratio of light output from a lamp to the electric power it consumes and is measured in lumens per watt (LPW).

  19. Improved Lighting Controls • Snap Switches • Photocells • Timers • Occupancy sensors • Dimmers

  20. Resources • http://www.eren.doe.gov/erec/factsheets/eelight.html • http://www.misty.com/~don/dschlamp.html • LIGHTING FUNDAMENTALS

More Related