Energy Efficient Lighting & How to Implement It
It has been estimated that lighting accounts for about 20% of the total power generation of the world. The quality and quantity of light not only affects our health, comfort, safety and productivity but also affects the economy. Many nations have been spending a huge amount of their electricity budget on lighting.
For achieving efficient use of electricity, nations have been taking a sustained switch to the energy efficient lighting which is the most cost effective and reliable method of energy-saving. A well known technologies have been in use in the area of lighting to optimize the existing controls and lighting equipment for reducing the energy consumption with higher lighting quality. Let us discuss in detail about this concept.
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What is Energy Efficient Lighting?
When the energy usage of a product is reduced without affecting its output or final response or user comfort levels is referred as energy efficiency. An energy efficient product consumes less energy to perform the same function when compared to the same product with more energy consumption.
The energy efficiency in the lighting sector gives the required illumination level of the lighting scheme for the application it has been designed for, while consuming the least amount of energy. Simply, energy efficient lighting can save the electricity while maintaining good quality and quantity of the light.
Energy efficient lighting involves in replacement (or re-lamping) of traditional lamps (such as incandescent lamps) with that of energy efficient such as fluorescent lamps, CFL lamps and LED lamps. It also incorporates proper lighting controls such as timer controls, PIR and ultrasonic sensors based controls, etc.
It includes the turning off lights automatically when they are not in use, especially during daylight. It uses electronic chokes instead of ballasts in case of conventional lighting and also with the use of electronic circuitry; it can achieve dimming of lights when necessary.
These energy efficient schemes can be applied for external lighting, internal lighting for residential buildings and internal lighting for commercial buildings. These schemes not only reduce the energy consumption, but also enhance the lighting quality, increase the safety and staff well-being, and reduce the environmental impacts.
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What is the Need for Energy Efficient Lighting?
Lighting is the basic requirement of any facility and it impacts the day-to-day activities of the people. This accounts a considerable amount of total energy consumption in domestic, commercial and industrial installations.
In industries, energy consumption for lighting constitutes only a small component of the total energy consumed, which is nearly 2-5 percent of total energy consumption. It accounts for 50 to 90 per cent in the domestic sector and it may go up to 20-40 percent in case of commercial /building sectors, information technology complexes, and hotels.
So it becomes an important area wherein energy to be conserved, especially in the domestic sector. Lighting efficiency solutions therefore play a key role in energy saving opportunities.
Due to the high energy consumption, traditional incandescent lamps and high discharge lamps have to be substituted with energy efficient lamps. Traditional lamps not only consume large amounts of electric power, but they use much of its consumed energy to produce heat rather than light (for instance 90% of consuming energy in case of incandescent lamps).
With the installation of energy efficient lighting, the amount of energy consumption eventually will get reduced and it results in lower electricity bills.
Hence the energy efficient lighting is necessary
- To reduce electricity consumption, thereby reduces the electricity bills
- To save electricity rather than wasting in terms of losses
- To lower greenhouse emissions because conventional lamps cause CO2 emissions
- To achieve peak load reduction
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Tips, Tricks & Techniques to Implement Energy Efficient Lighting
The best and effective solution for energy conservation is the adoption of energy efficient lighting technologies in the lighting sector, which facilitates comprehensive redesigning of lighting and control systems.
There have been major improvements and innovations in lighting technologies which can offer a great potential for energy savings in many lighting applications such as household lighting, street lighting, hospitality and retail spotlights, office and industrial lighting, etc.
The following are the techniques or types of energy efficient lighting which are commonly practiced as energy-saving opportunities.
Re-lamping with Energy-Efficient Lights
Energy efficient lamps can deliver the same amount of lighting with greater energy saving at low cost, when compared with conventional lamps. Traditional incandescent lamps consume a lot of energy to produce light in which 90 percent of consumed energy is given off as heat and also they consume more energy, typically 3-5 times more than the actual amount to produce light.
Energy efficient lamps overcome these problems by offering many more advantages than incandescent lamps. The two most popular choices of energy efficient light bulbs include CFLs (compact fluorescent lamp) and LED (light emitting diode) lamps.
Compact Fluorescent Lamps (CFLs)
CFL lamps are miniature or curly versions of long-sized fluorescent tubes. These lamps combine the efficiency of fluorescent lighting with the popularity and convenience of incandescent fixtures.
They screw in to the fixtures that allow all standard incandescent lamps, but not into standard fluorescent fixtures of long tubes. Depending on the brand and application use, they come in different range of styles, colors and sizes.
CFLs use 75 percent less energy and produce 75 percent less heat for producing the same amount of illumination as compared with incandescent lamps. They last 10 to 15 times longer and cost 10 to 20 more as compared to incandescent lamps.
These lamps are made with a phosphorous glass tube consisting of inert gas (argon) and mercury vapor. They use an electronic ballast to create high voltage during the starting and it can be a separate unit or permanently built in lamp. Some special and older models of CFLs come with separate ballast while some CFLs come with inbuilt ballast.
When an electric current is passed through the electrodes, the electrons that are bound to mercury atoms are excited which in turn emits ultraviolet light. As UV light strikes the fluorescent coating, it will be converted into visible light.
Comparison chart for incandescent, CFL and LED bulbs.
There are different types of CFL lamps available in today’s market. Some of these are spiral lamps, triple tube lamps, standard lamps, globe lamps, flood lamps and candelabra lamps. In case of replacing incandescent lamps, CFLs are chosen to match lumens that indicate the amount of light being generated as shown in figure below.
These are available in a variety of light colors such as warm white and soft white, cool white and bright white, etc. depending on the type of application. The table below illustrates a range of light colors of CFLs for specific application.
Light Emitting Diodes (LEDs)
LEDs are solid state semiconductor devices and are more energy efficient than even CFLs. They produce little heat and higher quality lighting than any other lamp. At the time of inception the usage of LEDs was limited as single bulb indicators in electronic circuits.
Later a number of LEDs are clustered to develop small lamps in battery powered devices such as charging lights, flashlights, etc. Today, LED lamps are available in many new bulb styles which are bright enough to replace traditional incandescent lamps.
LED lamps use 75 percent less energy than traditional incandescent and 50 percent less energy than that of a CFL. They can last 8-25 times longer compared to incandescent and up to four times longer than a CFL. Unlike incandescent and CFLs, LED lamps produce no heat and hence they are cool enough to touch. But, these are more expensive; however, they are affordable over the long run.
LEDs are made up of semiconductor materials to form PN junctions. Whenever current flows across these junctions, it releases the energy in the form of a light. The wavelength and hence the color of the light depends on the composition of materials. LEDs can generate yellow, red, blue, green and white light. For lighting purpose several white color LEDs are stacked as clusters to produce required lighting for an application.
LED bulbs are available in different shapes, sizes and styles according to the type of application it is intended for. Some of these types include diffused bulbs, dimmable globe LED bulbs, track lighting pin-base type bulbs, flood reflector screw-in base bulbs, flame tip candelabra base LEDs and LED tube lights.
Comparison of incandescent, CFL , LED and halogen bulbs and lamps.
Improving Lighting Controls
Lighting can be controlled with the use of various sensors to allow the operation of lamps whenever they are needed. These sensors detect the presence of humans, motion, timing or occupancy and based on the sensor output, it switches the lamps ON and OFF. Types of these controls include infrared sensors, automatic timers, motion sensors (PIR and ultrasonic sensors), and dimmers.
Photo sensors monitor the daylight conditions and accordingly send the signals to main controller to turn the lamps automatically off at dawn and on at dusk. This type of lighting control is commonly used with street lighting and outdoor lighting.
Street lighting is another major area of energy conservation as it contributes considerable power consumption especially in the highways. Centralized control systems are most commonly used in street light control.
The popular centralized control is the SCADA (supervisory control and data acquisition) system which ensures remote control of operation of street lights from a central location. GSM/GPRS based systems also used to perform the remote control operation of street lights.
Replacing of Existing Fixtures and Ballasts
Replacing energy inefficient accessories with new energy efficient fixtures and ballast gives superior energy savings, longevity, and reliability. The main function of a luminaire or lighting fixture is to distribute, direct and diffuse light.
Some fixtures can absorb more than half of the illumination emitted the bulb that reduces the efficiency of the lighting. The higher efficiency fixtures can emit more light and hence one can save energy and money. Such fixtures consist of reflectors to direct the light in a desired direction.
All discharge lamps require a ballast for achieving required operation. Conventional magnetic type ballasts cause power losses which is typically 15 percent of the lamp wattage. It also can raise fixture temperature during operation. So the proper ballast must be chosen to reduce ballast losses, fixture temperature and system wattage. In today’s market, many electronic or solid state types of ballast are available which can save 20 to 30 percent energy consumption over standard ballasts.
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