Design Strategies

Energy efficient lighting
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Energy efficient lighting

1. Introduction
According to a survey that was conducted by the Energy Conservation Center Ho Chi Minh of 300 buildings, 10 percent to 20 percent of electricity is consumed by lighting systems in buildings in Viet Nam. Therefore it is a necessity to take advantage of daylighting and have efficient lighting systems to make substantial savings. Compact fluorescent lamps (CFL) and Light emitting diodes (LED) are relevant options for an energy efficient lighting system.

2. How they work
A compact fluorescent lamp (CFL), also known as a compact fluorescent light bulb is a type of fluorescent lamp. CFLs are designed to replace incandescent lamps and can fit in the existing light fixtures used for incandescent. In a CFL, an electric current is driven through a tube containing argon and a small amount of mercury vapor. This generates invisible ultraviolet light that excites a fluorescent coating (called phosphor) on the inside of the tube, which then emits visible light.
Light Emitting Diodes (LEDs) are part of a class of lighting called Solid State Lighting (SSL). The LED works by using an electric current traveling through a negatively charged cathode. Basically, a diode only allows an electric current to travel in one direction. This current causes electrons to recombine, which releases energy in the form of photons, light.

3. Benefits of energy saving light bulbs
• Savings: same illuminance level can be maintained whilst saving operating cost. Moreover, less heat is produced, which in turn reduces the cooling load on home air conditioners.
• Life expectancy: The light bulb’s life is extraordinarily longer than an incandescent bulb. A typical 60 watt incandescent will last 1,200 hours; a CFL will last 8,000 hours, and studies are showing that an LED will last up to 50,000 hours.

Comparison Chart Led lights, Incandescent Light Bulbs and CFLs (1)

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4. Application
a, Compact Fluorescent Lamps CFLs can be used anywhere an incandescent light bulb was used. Special CFLs need to be used in way lights with dimmers or outdoors. b, Light Emitting Diodes LEDs are already being used in a variety of applications:
• Decorative lighting strings (both indoor and outdoor)
• Traffic lights
• Outdoor lighting fixtures for parking lots, streets, and parks
• Architectural lighting
• Retail display lighting
• Desk and task lights
• Home lighting applications such as recessed down-lights and under-cabinet lights
LED applications allow for extraordinary flexibility in lighting design with regard to color, brightness, size, shape, and distribution.

References

(1) http://www.designrecycleinc.com/led%20comp%20chart.html
(2) http://www.sanibulb.com/cfl.html
(3) http://www2.ca.uky.edu/agc/pubs/fcs4/fcs4410/fcs4410.pdf

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