advantages of leds

7/28/2019 Advantages of LEDs

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LEDs cam be very small and are easily populated onto printed circuit boards. LEDs do not contain mercury, as compact fluorescent lamps do.

NO infra-red or ultra-violet radiation: Conventional light sources are plagued by infra-redand ultra-violet radiation, which has detrimental effects.

DISADVANTAGES OF USING LEDS LEDs are currently more expensive, price per lumen, on an initial capital cost basis, than

more conventional lighting technologies. The additional expense partially stems from therelatively low lumen output and the drive circuitry and power supplies needed. However,when considering the total cost of ownership (including energy and maintenance costs),LEDs far surpass incandescent or halogen sources and begin to threaten compactfluorescent lamps.

LED performance largely depends on the ambient temperature of the operatingenvironment. Driving a LED hard in high ambient temperatures may result in

overheating of the LED package, eventually leading to device failure. Adequate heat-sinking is required to maintain long life. This is especially important when considering

automotive, medical, and military applications where the device must operate over a largerange of temperatures, and are required to have a low failure rate.

LEDs typically cast light in one direction at a narrow angle compared to an incandescentor fluorescent lamp of the same lumen level.

The spectrum of some white LEDs differs significantly from a black-body radiator, suchas the sun or an incandescent light and can cause the color objects to be perceiveddifferently under LED illumination than light sources.

LEDs Vs Traditional Light Sources in the contemporary Indian Urban/ Rural scenarioLEDs used as a replacement for incandescent light bulbs and fluorescent lamps are known assolid-state lighting (SSL)packaged as a cluster of white LEDs grouped together to form a light

source. LEDs are moderately efficient; the average commercial SSL currently outputs 32 lumensper watt (lm/W), and new technologies promise to deliver up to 80 lm/W. The long lifetime ofLEDs make SSL very attractive. They are also more mechanically robust than incandescent lightbulbs and fluorescent tubes. Currently, solid state lighting is becoming more available forhousehold use but is relatively expensive, although costs are decreasing.

However the high cost is a major obstacle but the benefits could outweigh the costdisadvantage.

LED Penetration to General L ighti ng Obstacles: Price

Incandescent lamps are very popular and widely used in India and due to its very cheap price (Rs

10) and easy availability. But they are highly inefficient and do not last long. The IndianGovernment is reportedly considering a slow phase out of incandescent lamps replacing themwith CFLs and LED lighting.Fluorescent Tubes (Tube Lights) are more efficient, providing 50 to 100 lm/W for domestictubes (average 60 lm/W), but are bulky and fragile and require starter or ballast circuits.Available in 2ft and 4 ft sizes with Aluminium, Copper and Electronic ballasts, they very wellentrenched in both urban and rural India.


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Compact Fluorescent lamps (CFLs), which include quiet integrated electronic ballast, arerelatively robust and efficient and fit in standard light bulb sockets and currently appear to bemost attractive energy efficient option. CFLs are becoming cheaper and more accessible by theday and with a number of new manufacturers entering the arena, prices are dropping. BrandedCFLs with 1 year warranty are available in retail, from Rs 80-Rs 200, depending on wattage

from 2W to 36W. The CFLs have been promoted by governments due to their high power savingcapability.But CFLs do have a few problems like lower power factor, which is some what expensive tocorrect, generation of harmonics due to electronic ballasts and mercury content which ishazardous to environment. A compact fluorescent bulb generally contains only a few milligramsof mercury. As long as the bulb remains intact, this mercury is not released to the environment.When the lamp burns out (and they are designed to have a much longer life than conventional

bulbs), they should be disposed of in an environmentally sound way. Governments are givingserious consideration to such disposal issues. Manufacturers on their part, are currently workingon reducing mercury in CFLs to the minimum.Induction lamps are electrode-less fluorescent lamp driven by high-frequency current, typically

between 250 kHz and 2.65 mHz, usually via an external generator. They are available in limitedwattages and are known for exceptionally long service life: up to 100,000 hours, Lamp efficaciestypically range from 64 to 88 lumens per watt.Color rendition with induction lamps is very good. Although not easily optically controllable in aluminary because of the large lamp size, induction lighting is often employed in applicationswhere luminaries may be very difficult to access or where maintenance costs are a strong factorin the lighting design and installation. Initial system purchasing costs are high compared to thebest HID or fluorescent systems. Although induction lamps could be a serious contender forfuture lighting, some how, induction lamps have not caught the fancy for larger usage.The white LEDs are slowly but surely establishing their presence in India. In addition to signaland indicator lighting, LEDs are increasingly finding use in commercial and industrialenvironments. Considering the current power shortages, Ministry of Power & Bureau of EnergyEfficiency and state governments have, shown interest in adopting LED lighting due to its manyadvantages.In the rural environments LED lights are an ideal match to a solar / battery power system,because of their very low power consumption. This, coupled with their very long life, and strongresistance to heat, cold, vibration and moisture, make LED forms of lighting suited to any solarapplications, but particularly to remote areas, where normal power supply is non-existent. LEDscontinue to emit light even when the battery has drained out to the level of 80%. Batteries areeasy to recharge /maintain. BIS has also drafted specifications for LEDs with a sealed batteryand PV Solar Modules for power / charging with an average duty cycle of 4 hrs / day.

COMPARISON CHART LED LIGHTS VS. INCANDESCENT LIGHT

BULBS VS.CFLS

Energy Efficiency & Energy

Costs

Light Emitting

Diodes (LEDs)Incandescent

Light BulbsCompact

Fluorescents

(CFLs)

Life span (average) 50,000hours 1,200 hours 8,000hours


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Watts of electricity used(equivalentto 60watt bulb)LEDs use lesspower(watts)per unit of lightgenerated(lumens).LEDs help toreduce green house gas emissions

from the power plants and lowerelectric bills

6-8 watts 60watts 13-15 watts

Kilo-watt of electricity used(30Incadescent bulbs per yearequivalent)

329KWh/yr 3285KWh/yr 767KWh/yr

Annual operating cost (30Incadescent bulbs per yearequivalent)

$32.85/year $328.59/year $76.65/year

Environmental Impact Light Emitting

Diodes (LEDs)

Incandescent

Light Bulbs

Compact

Fluorescents(CFLs)

Contains the TOXIC mercury No No Yes- mercury isvery toxic to yourhealth and theenvironment.

RoHS Compliant Yes Yes No-Contains1mg-5mg ofMercury and is amajor risk to theenviroment

Carbon Dioxide Emissions(30 bulb per year) Lower energyconsumption decreases CO2emissions, sulphur oxide and highlevel nuclear waste.

415 pounds/year 4500 pounds/year 1051 pounds/year

Important facts Light Emitting


Light BulbsCompact

Fluorescents

(CFLs)

Sensitivity to low temperature None Some DegreesFahrenheit or

over 120 degreefahrenheit

Sensitivity to Humidity No Some Yes

On/Off Cycling switching a CFLon /off quickly in closet forinstance,may decrease the life spanof the bulb.

No effect Some Yes-can reducelife spandrastically

Turns on instantly Yes yes No- takes time to


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warm up.

Durability Very durable-LEDs canhandle jarringand bumping

Non very durable-glass and filamentcan break easily.

Not very durableglass can breakeasily

Heat emitted 3.4 btus/hour 85 btus/hour 30 btus/hourFaiure modes Not typical Some Yes-may catch on

fire,smoke oromit an odor.

Lighting output Light Emitting


Light BulbsCompact

Fluorescents

(CFLs)Lumens Watts Watts Watts

450 4-5 40 9-13

800 6-8 60 13-16

1,100 9-13 75 18-251,600 16-20 100 23-30

2,600 25-28 150 30-35

While the initial capital cost is higher, the total lifetime cost of ownership isextremely low.

The payback period can be as low as 3 to 4 years (after which the product

essentially becomes free for the next 10 to 15 years).

The payback period of 36Watt LED Light Fittings procured by NSPCL, Rourkela is describedbelow as an example:-

Initial Cost of 36W LED Lights Rs. 6800.00

Guaranteed Running Hours 50000 hours

Initial cost of 2x 36W CFL Lights Rs. 2800.00

Running hour of CFL Lamps =8000 hours (two lamps per year,eight lamps in 4 years)

Rs. 120.00 x 8 = Rs. 960.00

Initial + Running cost of CFLlamps for three years

Rs. 3760.00

Incremental cost in LED Light Rs. 3040.00Wattage saved compared to 2 x36Watt CFL

36W

Wh saved in 12 hours running 432Wh = 0.432 Units

Cost of energy saved per day 0.432 Units x Rs. 4.00 = Rs. 1.728

Cost of energy saved for 4 years Rs. 1.728 x 365 x 4= Rs. 2523.00


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Thus the incremental cost of LED Lights is payed back in almost 4 years. However other costslike procurement process cost of spare CFLs and replacement cost of the lamps are not taken intoaccount in the above calculation.

CONCLUSION:-

Considering the advantages of LED Lights as described above, NSPCL, Rourkela has takenmany other initiatives as given below:-

1. Replacement of NSPCL Logo Display to LED Display in place of existing Neon LightDisplay

2. Replacement Panel Indication Lamps of all areas by LED indication lamps.3. Installation of LED Aviation Lights in Chimneys.

In future NSPCL, Rourkela plans to replace LED Lights in other areas like control rooms andother areas.

advantages of leds

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