• Electrical India
  • Apr 5, 2015

Eco Friendly LED & CFL A Comparative Statement

LED lamps now compete with CFLs for high-efficiency house lighting. The desire to reduce electrical loading by using energy efficient lighting has resulted in a high level of interest in replacing conventional incandescent lamp with Compact Fluorescent Lamps and LED lamps. However, their high harmonic content was always a problem for the power quality of the power system networks, especially the ones with a considerable share of nonlinear loads.

- Shridhar Shantaram Khule,
Haridas M Kakad and Dhanshri P Birar


 The problem of harmonics cannot be neglected in cases of installations with high lighting load. This article presents an analysis of harmonics in a network where lighting is one of the main loads. CFLs and LED lamps with electronic gear are characterized by extremely distorted current, with high total current harmonic distortions. Hence they cause a significant voltage distortion in electrical installations. A comparative analysis is performed on the power quality, maximum loading and economics of CFL lamps and LED lamps.

Greenhouse gases & LED

  The heat generated by conventional electric light bulbs may have been significantly reducing the release of greenhouse gases from natural gas. If all homes switch from (incandescent) bulbs to CFLs, there would be an increase of almost 220,000 tonnes in CO2 emissions in the province, equivalent to the annual emissions from more than 40,000 automobiles. As CFL Contains Mercury, Net mercury emissions for CFL and incandescent lamps is 0.012 mg of mercury per kilowatt-hour and 14% of CFL mercury contents escapes to environment after land fill disposal. CFLs, like all fluorescent lamps, contain mercury as vapor inside the glass tubing. Most CFLs contain 3–5 mg per bulb. As mercury is poisonous, even these small amounts contribute to air and water pollution.

  According to the European Commission Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR) in 2008, CFLs may pose an added health risk due to the ultraviolet and blue light emitted. This radiation could aggravate symptoms in people who already suffer skin conditions that make them exceptionally sensitive to light. The light produced by some single-envelope CFLs at distances of less than 20 cm (7.9 in) could lead to ultraviolet exposures approaching the current workplace limit set to protect workers from skin and retinal damage. However, industry sources claim the UV radiation received from CFLs is too small to contribute to skin cancer and the use of double-envelope CFLs "largely or entirely" mitigates any other risks.

  An LED lamp is a light-emitting diode (LED) product that is assembled into a lamp (or light bulb) for use in lighting fixtures. LED lamps have a lifespan and electrical efficiency that is several times better than incandescent lamps, and significantly better than most fluorescent lamps, with some chips able to emit more than 100 lumens per watt.

  Like incandescent lamps and unlike most fluorescent lamps (e.g. tubes and compact fluorescent lamps or CFLs), LEDs come to full brightness without need for a warm-up time; the life of fluorescent lighting is also reduced by frequent switching on and off.

  Some governments around the world have passed measures to phase out incandescent light bulbs for general lighting. The aim is to encourage the use and technological development of more energy-efficient lighting alternatives, such as Compact Fluorescent Lamp & LED lamps. Consumers are being encouraged to switch outdated incandescent bulbs to these more energy efficient alternatives. LEDs are more efficient than CFLs but the initial cost is higher so it takes longer to recoup the cost of the bulb. However LEDs last much longer-over 20 years-so they will pay for themselves many times over their lifespan. While an 11w CFL bulb costs $1.25 in bulk, an 8w LED (which produces the same number of lumens as a 40w incandescent bulb) can run anywhere from $10 (available at local hardware stores) to $20.

Environmental impact of LED lamps compared to halogen lamps

  • The environmental benefits of using LED lamps to replace Halogen lamps are unquestionable.
  • At least 4 times less impact on all environmental impact categories throughout its product life cycle.
  • Still significantly lower than that of low voltage halogen lamps even when, extremely high halogen specs are considered.
  • The environmental impact calculations are corrected for flux or central beam intensity differences. The LED lamp power is doubled and life-time of the LED lamp is reduced by half (sensitivity analysis).

Why Only LEDs

  • LEDs are ideal for use in applications that are subject to frequent on-off cycling, unlike fluorescent lamps that burn out more quickly when cycled frequently, or HID lamps that require a long time before restarting.
  • LEDs can very easily be dimmed or strobed.
  • LEDs light up very quickly. A typical red indicator LED will achieve full brightness in microseconds. 
  • LEDs mostly fail by dimming over time, rather than the abrupt burn-out of incandescent bulbs.
  • LEDs, being solid state components, are difficult to damage with external shock, unlike fluorescent and incandescent bulbs which are fragile. 
  • LEDs can be very small and are easily populated onto printed circuit boards. 
  • LEDs do not contain mercury, unlike CFL.

Basic advantages of LED Light

  • Energy efficient: LED’s are now capable of outputting 135 lumens/watt
  • Long Lifetime: 50,000 hours or more if properly engineered
  • Rugged: LED’s are also called Solid State Lighting (SSL) as they are made of solid material with no filament or tube or bulb to break
  • No warm-up period: LED’s light instantly – in nanoseconds 
  • Not affected by cold temperatures: LED’s “like” low temperatures and will startup even in subzero weather
  • Directional: With LED’s you can direct the light where you want it, thus no light is wasted
  • Excellent Color Rendering: LED’s do not wash out colors like other light sources such as fluorescents, making them perfect for displays and retail applications
  • Environmentally friendly: LED’s contain no mercury or other hazardous substances
  • Controllable: LED’s can be controlled for brightness and color.

Energy efficiency

  Energy usage for different types of light bulbs operating at different light outputs. Points lower on the graph correspond to lower energy use Because the eye's sensitivity changes with the wavelength, the output of lamps is commonly measured in lumens, a measure of the power of light as perceived by the human eye. The luminous efficacy of lamps is the number of lumens produced for each watt of electrical power used. The luminous efficacy of a typical CFL is 50–70 lumens per watt (lm/W) and that of a typical incandescent lamp is 10–17 lm/W. Compared to a theoretical 100%-efficient lamp (680 lm/W).

Comparison Between Different Light Sources

  CFL lamps have lighting efficiency ranges of 7–10%, versus 1.5–2.5% for incandescent Because of their higher efficacy, CFLs use between one-seventh and one-third of the power of equivalent incandescent lamps. Fifty to seventy percent of the world's total lighting market sales were incandescent in 2010. Replacing all inefficient lighting with CFLs would save 409 terawatt hours (TWh) per year, 2.5% of the world's electricity consumption. In the US, it is estimated that replacing all the incandescent would save 80 TWh yearly.

  Since CFLs use much less energy than incandescent lamps (ILs), a phase-out of ILs would result in less carbon dioxide (CO2) being emitted into the atmosphere. Exchanging ILs for efficient CFLs on a global scale would achieve annual CO2 reductions of 230 Mt (million tons), more than the combined yearly CO2 emissions of the Netherlands and Portugal.

Conclusion

  LEDs are Competitive, Eco Friendly & Likely to Get Better. Conclusion is that based on eco-friendly, life-cycle assessments and competitiveness, LEDs are about as energy efficient as CFLs as far as their whole life-cycle is concerned. But that seems likely to change, since LED lighting technology is still growing and improving its own performance day-by-day.


Authors are from Matoshri College of Engineering & Research Centre and K K Wagh Polytechnic.

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