|retrofit could replace conventional tubelights and bulbs .|
- CFLs) combine the efficiency of fluorescent lighting with the convenience and popularity of
incandescent bulbs. CFLs come in pin-based and screw-based configurations. Pin-based
models are designed to fit only into fixtures that are designed for fluorescent lighting. Screw-
based CFLs are designed to fit into fixtures where you would typically use a conventional
incandescent light bulb.
CFLs can provide as much light as incandescents that are roughly three to four times their wattage,
saving at least 66% of the initial lighting energy. Although CFLs cost more than incandescents, they
last about 10 times as long (10,000 hours or more). The energy savings and superior longevity make
CFLs the more cost-effective choice, saving about $25 over the life of the CFL in energy and bulb
CFLs are available in a variety of styles or shapes, including double- or triple-tubes, the popular
spiral shape, covered lamps that look like typical incandescent bulbs, and decorative globe and
candelabra shapes. The size or total surface area of the tube(s) determines how much light it
produces. Manufacturers have worked to reduce the size of CFLs while improving light output and
quality — and reducing the cost — so that it is now easy to find a CFL to fit almost any fixture
- Design of building while in drawing/planning stage could be made in such manner that
maximum sunlight can be used .
- solar panels ( solar voltalic ) lights can be used to light the factory premises . Factory sheds
can have openings with transparent sheet providing daylights and minimising use of lights
during day time .
Photocells turn off or dim lights when daylighting in the space is sufficient. Photocells are often used
with outdoor lighting, but may be connected to lights near windows or under skylights. Typically,
photocells are not as effective with indoor lights that are farther than 12 feet from an outdoor lighting
"Daylight dimming" switches may offer appreciable energy savings for lighting near windows or
skylights. "Step dimming" reduces lighting levels at fixed intervals, typically in two or three steps.
Manual dimming may be appropriate for spaces where presentations or computer tasks are
performed. Incandescent, fluorescent and high-intensity discharge (HID) lights all have different
dimming characteristics; HID lighting is the least favorable. The three primary ways to dim fluorescent
lamps are with low-voltage controlled ballasts, power-line controlled ballasts and panel-level
In rooms where the lights are frequently left on, or where rooms are left unoccupied for large periods
during the day or night, an occupancy sensor can cut lighting costs by as much as 50%. For
occupancy sensors, two technologies dominate: infrared and ultrasonic.
Infrared sensors detect temperature changes in a room, and work well if the entire room is within the
sensor's field of view. When a change in heat is detected, the sensor switches the lights. The
drawback is that infrared sensors have a range of approximately 15 feet, and therefore only work in
small areas. ·
Ultrasonic sensors use high-frequency sound to detect motion. The sensors monitor the reflection
pattern of the sound off objects in the room; when the pattern changes, the sensors switch the lights
on. When the pattern does not change for a while, the sensors switch the lights off. The drawback to
ultrasonic sensors is that they can be triggered falsely by objects in the room, such as window
curtains that are moved by a breeze. These sensors have a greater range than infrared sensors and
are best deployed in larger areas. Dual-technology sensors use both infrared and ultrasonic
methods, which make them more accurate and versatile. However, dual-technology sensors are more
There many types of switches by which we can save energy in lighting in building /offices/plant.Like
elapsed time switches and bi level switches.