Induction lights vs led lights green tech fixtures


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Induction lights vs led lights green tech fixtures

  1. 1. By L. Michael Roberts © 2010 - L. Michael Roberts - All Rights Reserved Published under the terms of Creative Commons Attribution-Noncommercial 3.0 license - Reproduced with permission For More Information Please Contact: GreenTech Fixtures Inc. 56 Stanley Street, Goderich, Ontario, Canada N7A 3K5 Tel: 519-955-4354 Fax: 519-524-8416
  2. 2. MAGNETIC INDUCTION LIGHTS VS. LED LIGHTS BY L. MICHAEL ROBERTS ABSTRACT By now, it is evident that we are facing an energy problem - while our primary sources of energy are running out, the demand for energy is continuously increasing. In the face of this situation, energy-efficient lighting systems have become a hot topic. Energy for lighting can consume between 60% (in educational settings) and 31% (in retail store applications) of an organizations electricity budget. As the cost of energy rises, people are seeking ways in which to reduce energy consumption. The main reason is financial, but the spectre of Global Warming (climate change) and respect for the environment by reducing CO2 emissions, also plays a role. A great deal of R&D work has gone into finding improved lighting technologies which consume less energy while still providing the needed light levels. One of the most publicised, is the replacement of household incandescent lamps with Compact Fluorescent Lamps (CFL) which has done much to reduce energy consumption in the consumer sector. Unfortunately, for commercial and industrial applications, CFL lights are not always suitable. In these types of applications, not only are high light levels required, but longevity is also a factor to keep maintenance costs reasonable. The two leading contenders for industrial and commercial lighting applications are Magnetic Induction Lamps (also called Induction Lights) and Light Emitting Diodes (LED) lighting. This paper compares the current state of these two lighting technologies and demonstrates, scientifically, that Induction Lighting is the best, and most energy efficient choice, for a wide range of applications. TECHNOLOGY BACKGROUND Before undertaking a comparison of the relative merits of of Magnetic Induction Lighting and LED Lighting in commercial and industrial applications where high light levels are required, we first review the basics of the two technologies. Magnetic Induction Lamps: Magnetic induction lamps are basically fluorescent lamps with electromagnets wrapped around a part of the tube, or inserted inside the lamp. In external inductor lamps, high frequency energy, from the ballast, is sent through wires, which are wrapped in a coil around the ferrite inductor on the outside of the glass tube, creating a powerful magnet.[1] The induction coil produces a very strong magnetic field which travels through the glass and excites the mercury atoms in the interior. The mercury atoms are provided by the amalgam (a solid form of mercury). The excited mercury atoms emit UV light and, just as in a fluorescent tube, the UV light is up-converted to visible light by the phosphor coating on the inside of the tube. The glass walls of the lamp prevent the emission of the UV light as ordinary glass blocks UV radiation in the 253.7 nm and 185 nm range. Magnetic Induction Lamps Vs. LED Lights - Page 1 Page
  3. 3. The induction system can be considered as a type of transformer where the inductor outside the glass envelope acts as the primary coil, while the mercury atoms in an inert gas-fill within the envelope/tube form a single-turn secondary coil. The high frequency magnetic field from the inductor is coupled to the metallic mercury ions causing their electrons to reach an excited state. When the electrons revert to the ground state, photons of UV light are emitted which excites the phosphor coating to emit visible light. In a variation of this technology (the internal inductor lamp - photo left), a light bulb shaped glass envelope, which has a test-tube shaped re-entrant central cavity, is coated with phosphors on the interior, evacuated, then filled with an inert gas and a pellet of mercury amalgam. The induction coil is wound around a ferrite shaft which is inserted into the central test-tube like cavity. The external inductor lamps (photo right) have the advantage that the heat generated by the induction coil assemblies is external to the tube and can be easily dissipated by convention or conduction. The external inductor design lends itself to higher power output lamp designs which can be rectangular or round. In the internal inductor lamps, the heat generated by the induction coil is emitted inside the lamp body and must be cooled by conduction to a heat-sink at the lamp base, and by radiation through the glass walls. The internal inductor lamps tend to have a shorter lifespan than the external inductor types due to the higher operating temperatures. The internal inductor type lamps look more like a conventional light bulb than the external inductor type lamps, so may be more aesthetically pleasing in some applications. As with conventional fluorescent lamps, varying the composition of the phosphors coated onto the inside of the induction lamps, allows for models with different colour temperatures. The most common colour temperatures of induction lamps are 3500K, 4100K, 5000K and 6500K but other colour temperatures, and even coloured versions are available. Ballasts: Magnetic induction lamps require a correctly matched electronic ballast (photo left) for proper operation. The ballast takes the incoming voltage and rectifies it to DC. Solid state circuitry then converts this DC current to a very high frequency which is between 2.65 and 13.6 MHz depending on the lamp design. The high frequency produced by the ballast is fed to the coil wrapped around the ferrite core of the inductor The ballasts contain control circuitry which regulates the frequency and current to the induction coil to insure stable operation of the lamp. In addition, the ballasts have a circuit which produces a large “start pulse” at power-up to initially ionize the mercury atoms and thereby start the lamp. The close regulation of the lamp’s inductor by the ballast, and the use of microprocessor controlled circuits, allows the electronic ballasts to operate at between 95% and 98% efficiency. Only around 2% to 5% of the energy is wasted in the induction lamp ballast compared to the 10-17% wasted in traditional “core and coil” type designs used with most High Intensity Discharge (HID) commercial and industrial lighting. Light Emitting Diodes: LEDs are a solid state, semiconductor, device much like a regular diode. A diode is the simplest form of semiconductor device - it conducts electricity in only one direction. A semiconductor is a material with a varying capacity to conduct electricity. Most semiconductors such as transistors and diodes are made of a poor conductor that has impurities (atoms of a different material - usually arsenic) added to it. The process of adding these impurities is called doping. In LEDs, the semiconductor material is typically aluminium-gallium-arsenide (AlGaAs). In AlGaAs, all of the atoms bond perfectly to their neighbouring atoms, leaving no free electrons to conduct electric current. In doped material, additional atoms change the balance of the conductivity in the material, either adding free Magnetic Induction Lamps Vs. LED Lights - Page 2
  4. 4. electrons, or creating holes where electrons can flow, in response to an electrical current. Either of these additions (free electrons or holes) make the material more conductive. A semiconductor with extra electrons is called N-type (as it has extra negatively-charged particles). In N-type material, free electrons move from a negatively-charged area to a positively charged area. A semiconductor with extra holes is called P-type (as it has extra positively-charged particles); electrons can jump from hole to hole, moving from a negatively-charged area to a positively-charged area. Just like in a regular diode, an LED consists of a small chip of semiconductor material - often less that 1 X 1 mm - doped with impurities to create a P-N type junction. As with regular diodes, current flows easily from the P-side (+ or anode), to the N-side (- cathode), but it can not flow in the opposite direction. When the current flows across the junction of the P and N semiconductors, and an electron meets a hole, the electron falls to a lower energy level. Since energy is neither created or destroyed, the excess energy in the electron is emitted as a photon of light. The colour (wavelength) of the light emitted, depends on the band gap (difference in energy levels) of the semiconductor materials forming the P-N junction. The types of materials used for LEDs have a band gap which can produce light varying from near-infrared, through visible, to near-ultraviolet light depending on the design of the LED. The small LED chip (sometimes called a die) is encapsulated (packaged) in a plastic casing along with the leads and sometimes other components such as a reflector or a heat-sink. Regular LEDs produce a small amount of heat during operation but the leads are usually enough to keep the die at a reasonable operating temperature. Higher output LEDs, and especially white-light LEDs produce larger amounts of heat, thus proper thermal management and heat-sinking is essential. If the LEDs were to operate about the maximum design temperature, the sensitive junction could become overheated and the LED will be destroyed. Power Supply: LEDs are a current sensitive device where brightness is proportional to the current applied (within the design specifications of the LED). If too much current is sent to the LED, the sensitive junction on the die (wire bond) will be destroyed and the LED will cease to function. In the case of lower output LEDs, such as those used in battery powered consumer applications (E.G.: flashlights), current limiting is provided by a resistor. In the case of higher power LEDs, or arrays of LEDs, a clean, constantly regulated current must be provided. Rather than calling this device a ballast (as we do with induction lighting), it is referred to as a power supply or PSU (see examples in photo). An LED power supply (PSU) serves the same function as the ballast in a Magnetic Induction Light. It takes the incoming mains power, rectifies it to DC, smoothes and filters the DC power, then uses electronics to provide a constant, direct current, to the LEDs. The use of microprocessor controlled circuits, allows the LED power supply to operate at between 85% and 95% efficiency. Only around 5% to 15% of the energy is wasted (as heat) in the LED power supply. White LEDs: There are no semiconductor materials for LEDs which emit while light directly. One can combine Red, Green and blue LED chips into a single encapsulation (RGB LED). This is often used in applications where low power but variably coloured light is desired such as in large screen TV displays for outdoor use (Jumbotrons), or in stage or building lighting with variable colours. Magnetic Induction Lamps Vs. LED Lights - Page 3
  5. 5. To make “white”, the R, G and B LED emitters can be turned on at full power producing an almost white light. Adjusting the relative brightness of the R, G and B emitters allows many shades of “white” (or other colours) to be produced. This is not an efficient process as additional electronics are required. For lighting applications, an LED that produces the maximum amount of white light output is desirable, so manufacturers came up with Phosphor coated LEDs. This involves coating the interior (or exterior) of a high output, single colour LED (mostly blue LEDs), with phosphors of different types to produce white light. These LEDs are technically called phosphor-based LEDs but most people refer to them as white LEDs. In a phosphor coated LED, a portion of the blue light emitted by the LED die is up-converted by the phosphor such that it is transformed from shorter wavelengths to longer wavelengths. Some of the blue light travels through the phosphors, mixing with the up-converted light emitted by the phosphors to provide “white” light output. Depending on the color emitted by the LED die, different phosphors can be used to produce different shades of white and thus different perceived colour temperatures. A number of layers of phosphors are usually applied such that the spectrum emitted is broadened, effectively increasing the color rendering index (CRI) of the white LED. These LEDs have a lower efficiency than regular LEDs due to the heat produced by the up-conversion process in the phosphors, and also due to other phosphor-related degradation issues.[2] The photo at right shows a 5 watt, white LED - note the large heat-sink the encapsulated LED is mounted on. The phosphor coating method is still the most popular technique for manufacturing high output “white” LEDs. Designing an producing a light fixture using a “white” LED is simpler and cheaper than using a complex R, G, B LED based system, thus the majority of high intensity white LEDs presently on the market use phosphor coating. The LED's Dark Secret The blue light-emitting diode, arguably the greatest optoelectronic advance of the past 25 years, harbours a dark secret: Crank up the current and its efficiencies will plummet. The problem is known as droop, and it’s not only puzzling the brightest minds in the field, it’s also threatening the future of the electric lighting industry. Richard Stevenson - IEEE Spectrum, August 2009 VISUALLY EFFECTIVE LUMENS OR PUPIL LUMENS There is wide agreement and scientific data[3,4] to show that the spectral distribution of the light produced by a particular lamp affects human vision. Higher blue output, sometimes referred to as “High Scotopic Output”, lamps appear brighter to the eye than the same wattage of lamp, with the same conversion efficiency, but with little or no blue output. Thus the lamp’s spectral distribution of light that is useful to the eye (human vision) is also a factor in perceived light quality and brightness. There is presently no scientific, or industry wide, consensus for a terminology to describe this phenomenon. The Author uses the term Visually Effective Lumens, or Visually Effective Lux (VEL) while others have used the term Pupil Lumens (PL). Visually Effective Lumens VEL of a lamp can be determined by multiplying the output in lumens by a conversion factor derived by measuring the spectral distribution of the light output. The conversion factors are derived from measuring the Scotopic/Photopic Ratio (S/P ratio) of a lamp. The S/P ratio is determined by measuring the amount of light being output in the Photopic sensitivity region, and the Scotopic sensitivity region, of the human eye, and then deriving the ratio of the two (see chart at top of next page). When the S/P ratio is used as a multiplier of the actual lamp output lumens, the amount of light useful to the human eye (VEL) can be determined. After all, we are lighting spaces for humans so the VEL must be taken into account. This correction factor can drastically changes the conversion efficiency of lamps, especially the High Intensity Discharge (HID) lamps used in commercial and industrial lighting applications. Generally speaking, both Induction and LED lights are available in 4,100K, 5,000K and 6,500K versions, thus we will limit our comparisons to the S/P ratios for these colour temperatures. The most common type of Magnetic Induction Lamps Vs. LED Lights - Page 4
  6. 6. high brightness LED lamps operate at 6,500K (6,500K Induction lights are also available). 6,500K is the EU (European) standard for “daylight”, while the North American “daylight” standard is 5,000K. Since the S/P ration of the two technologies is similar, the conversion efficiency of the source will be the greatest influence on the VEL produced by the two technologies. INDUCTION LAMPS VS. LED LAMPS While induction lamp technology has matured in the last several years, it is often overlooked or underutilized in lighting applications since none of the major manufacturers promote induction lamps in any significant way. LED lighting seems to get the most “buzz” in the market as LEDs are promoted as the best alternative to conventional lighting for energy efficiency and longevity. We will examine both these technologies in detail, based on manufacturers specifications sheets and a real-world example. For our real world example, we will compare two Garage/Canopy light designed for use in parking garages and other outdoor/damp locations using the data provided on the manufacturers specifications sheets. The Induction Lighting version is a GTF- GCL-100 which consumes a total of 103W of power (ballast GTF-GCL-100 included); the LED versions is an XGB-49 LED fixture, which consumes a total of 118W of power (PSU included). While these XGB-49 are not exactly matched for rated power consumption, they are close enough to make a valid comparison. Energy efficiency: The major difference between the two technologies (other than lifespan) is in conversion efficiency (energy utilization). Conversion efficiency is a measurement of the amount of light a lamp produces for a given amount of energy and is measured in Lumens per Watt - Lumens/Watt or L/W. • Most presently available commercial LED lighting fixtures have conversion efficiencies in the 35 to 65 Lumens/Watt (L/W) range.[5] LED elements with a conversion efficiency of 60~75 L/W are available, but still quite expensive.[6] There are reports of LEDs with conversion efficiencies of up to 100 L/W operating in research labs, but they are not yet commercially available. • Induction lamps have a conversion efficiency ranging from 65 L/W in low wattage (8~20 W internal inductor types) to 90 L/W in the high wattage lamps (250~400 W external inductor models).[3] Ongoing research will see some small improvements in these numbers. When considering commercial/industrial lighting and using a 200W lighting fixture as an example, the induction lamp version has a conversion efficiency of 82.5 L/W, while the LED equivalent will have a conversion efficiency in the range of 35~70 L/W. The Magnetic Induction Lamp fixture will produce 16,500 lumens of light, while the LED version will produce between 7,000 and 14,000 Lumens of light depending on the efficiency of the LEDs in the fixture. The Induction Lamp produces between 15.1% and 57.5% more light than the LED fixtures for the same amount of energy input. This is only taking “meter lumens” as measured into consideration. Once the correction factor for S/P ratio is applied, the Visually Effective Lumens (VEL) numbers will have an even greater difference. Magnetic Induction Lamps Vs. LED Lights - Page 5
  7. 7. The table (below) compares a 200W Magnetic Induction Lights with a 200W LED light fixture. Since the conversion efficiency of the LED lights varies per fixture in a range of 35~75 L/W, an average of 52.5 L/W is used. A more accurate comparison will be provided in the real world example further on in this paper. Comparison of Light Output, Electrical Energy Consumption and Power Cost - 200W Fixtures 200W LED 200W Light Type: (Average L/W) Induction Lamp Nominal wattage (Watts): 200 W 200 W [5] Total actual wattage (Ballast/Power Supply included) : 213 W 210 W Ballast/Power Supply overhead (Watts): 13 W 10 W Conversion efficiency (Lumens/Watt): 52.5 L/W 82.5 L/W Light output (Lumens): 10,500 L 16,500 L Colour Temperature (Kelvin): 6,500K 6,500K S/P Ratio (from chart): 2.25 2.25 Output corrected for VEL (VEL): 23,625 VEL* 37,125 VEL* Light output increase/decrease (%): 0% (Base) 36%* Energy savings (Watts / %): 0W / 0% (Base) 3W / 1.4% Energy cost for 100 hours operation (at $0.10/kWh $): $2.13 $2.10 * Note: A difference of +/- 10 to 15% in light levels is barely perceptible to the human eye - VEL and % figures rounded up/ down to nearest whole number. As we can see from the table, the Magnetic Induction Lamp produces 36% more light for the same energy input, while using 1.4% less energy than the LED light. While a savings of $0.03 per 100 hours may not seem like much, over the lifetimes of the fixture, the savings can be significant. Since the Magnetic Induction Lamp is producing significantly more light than the LED lamp, one can use a lower wattage Induction Lamp, where the light output is comparable to the LED light, to further increase energy savings. The table on the next page compares the 200W LED light with a 150W Induction light. In this comparison, the Induction Lamp is still producing 15% more light than the LED fixture, but is saving 25.8% percent more energy than the LED lighting, and saving $0.55 per 100 hours of operation. Lifespan: The next major factor to take into consideration is the operational longevity (lifespan) of the two technologies. The chart below shows the typical lifespan for the most frequently used types of commercial/ industrial lamp types. Magnetic Induction Lamps Vs. LED Lights - Page 6
  8. 8. Comparison of Light Output, Electrical Energy Consumption and Power Cost - 200W/150W 200W LED 150W Light Type: (Average L/W) Induction Lamp Nominal wattage (Watts): 200 W 150 W Total actual wattage (Ballast/Power Supply included)[5]: 213 W 158 W Ballast/Power Supply overhead (Watts): 13 W 8W Conversion efficiency (Lumens/Watt): 52.5 L/W 82 L/W Light output (Lumens): 10,500 L 12,300 L Colour Temperature (Kelvin): 6,500K 6,500K S/P Ratio (from chart): 2.25 2.25 Output corrected for VEL (VEL): 23,625 VEL* 27,675 VEL* Light output increase/decrease (%): 0% (Base) 15%* Energy savings (Watts / %): 0W / 0% (Base) 55W / 25.8% Energy cost for 100 hours operation (at $0.10/kWh $): $2.13 $1.58 * Note: A difference of +/- 10 to 15% in light levels is barely perceptible to the human eye - VEL and % figures rounded up/ down to nearest whole number. Internal Inductor lamps have a lifespan of between 60,000 and 75,000 hours of operation. Since the External inductor types have greater conversion efficiency and longer lifespan, we will focus primarily on that type. External Inductor lamps have a lifespan of 90,000 to 100,000 hours (depending on type and model). High power white LEDs presently have a lifespan in the 45,000 to 55,000 hour range. In this paper, lifespan is considered as useful life, not merely the time span when the lamp is outputting some light. In order to consider useful lifespan, we must take “Lumen Maintenance” into account. Lumen Maintenance is a measure of how well a lamp type maintains its light output. As any light source ages, the Lumen output declines - this is called “Lumen Depreciation”. Lumen Maintenance, or Lumen Depreciation, information is usually published as Lumen Maintenance curves which will show when the lamp should be replaced. The graph below shows the lumen maintenance curves for various commercial/industrial lighting technologies.[5] Magnetic Induction Lamps Vs. LED Lights - Page 7
  9. 9. Experts recommend that lamps should be replaced once they have depreciated to 70% of their initial output level.[7] While a drop in light output from a lamp of up to 15% is almost imperceptible to the human eye, a drop in light output of between 15% and 30% is quite noticeable to the human eye. In addition, some jurisdictions have regulations requiring certain minimum lighting levels be maintained for various kinds of tasks. Once the light output from any lamp falls below 70% of initial output, it may also fall below minimum output levels required by regulations. On the graph (previous page) the 70% lumen depreciation point is shown by a dashed red line. We can see that the high power LEDs reach that line at around 50,000 hours; while the External Inductor lamps reach the 70% line at around 85,000 hours - Magnetic Induction lamps last more than 40% longer than LEDs. Naturally, this is an approximation as the exact 70% lumen depreciation point will vary by make and model. We can also see that light output from the LEDs drops steeply after the 50,000 hour mark, while the Magnetic Induction Lamps are still producing more than 60% of rated output at 90,000 hours. This means that the induction lamps have a longer “grace period” for replacing aging lights. The useful lifespan of the two types of lighting has to be considered as it affects maintenance costs. The faster lamps reach the 70% lumen depreciation point, the more often they have to be replaced. In commercial and industrial lighting applications, re-lamping can be tedious and expensive. In the case of lamps that are mounted in a factory, equipment may have to be moved disrupting production, and often scaffolding, or a “cherry picker”, has to be brought in to access the fixtures. Even in the case of exterior lighting, re-lamping can cause interruptions in traffic flow and inconvenience workers and/or customers. In the case of most presently available LED lighting fixtures, the “bulb” can not be replaced. This is because the most powerful single element LEDs available at this time are in the 20~25W range. To make a 200W fixture, an array of LED elements must be used, and they require custom heat-sinks for thermal management. The nature of the heat-sink, and its dependence on proper contact with the shell of the fixture for heat dissipation, makes it all but impossible to change the array. Once the LED light reaches end-of-life, usually the whole fixture has to be replaced which adds significantly to maintenance costs. In contrast, the Induction Lamps are manufactured with mature glass moulding and coating technology and are generally mounted with screws that attach the inductors to the fixture. The Inductors themselves may be designed to be heat-sinks (see example in photo on right), or there may be a heat-sink integrated into the fixture to insure the lamps remain within the design temperature range. The Magnetic Induction Lamps can therefore be removed from the interior of the fixture and replaced when they have reached end-of-life. Based on the useful lifespan of the LED lights (around 50,000 hours ) compared to the useful lifespan of Induction Lights (around 85,000 hours), LED lighting will have a higher maintenance cost due to the requirement to purchase a new fixture every 50,000 hours; compared to purchasing a replacement lamp and ballast for the induction lighting every 85,000 hours. Acquisition Cost: Having touched on the cost of maintenance, the cost of the initial purchase of the lighting fixtures must also be considered. As mentioned, to make a 200W lighting fixture, an array of high power, white, LEDs must be used. This adds to the expense of the fixture as the cost of these more powerful LEDs is presently quite high since, as with any semiconductor device, the LED has to be fabricated before it can be tested to determine if it meets specifications. Due to many variables in the manufacturing process, there is a high rejection rate which produces a fair amount of material that can not be re-cycled adding to the overall cost of manufacturing. Since the LEDs are installed in an array, there is additional complexity and cost involved in the heat-sink and interconnections. All of these factors mean that, at present, LED fixtures are two to three times more costly than Magnetic Induction Lighting fixtures with comparable light output. Magnetic Induction Lamps Vs. LED Lights - Page 8
  10. 10. Induction lamps use well established and mature glass moulding and coating technology with electronic ballasts (similar to fluorescent lamp technology). As a result, Induction Lamp manufacturing costs are lower and yields higher than high power LEDs (at this time), and rejected lamps can be recycled for glass and metal recovery. Typically an induction lamp fixture will cost 50% to 75% less than a similar output LED based fixture. This cost gap will be erased over time as LED production ramps up, since sold-state devices are more amenable to cost reduction through mass manufacturing techniques. Advantage LEDs: The two areas where LED technology offers a significant advantage over induction lamps are compact form-factor and ruggedness. The availability of small LEDs that can be assembled into arrays, makes them ideal for applications such as, miniature fixtures, traffic signals or signs where a bright, compact, and often coloured light source is desirable. Since the LEDs are fully encapsulated solid-state devices, they are more resistant to vibration and impact compared to the induction lamps which are made of glass. LED lamps are therefore more suitable for applications where there is high vibration such as in transportation and industrial machinery applications. REAL-WORLD EXAMPLE As a real world example, we will compare two Garage/Canopy light Fixtures, one LED and the other Magnetic Induction Lighting, designed for use in parking garages and other outdoor/damp locations. We will use the data provided on the manufacturers specifications sheets and will perform additional calculations to determine lighting levels, VEL, power consumption and other factors which contribute to the Total Cost of Ownership (TCO). First we will look at energy (conversion) efficiency and light output: Conversion Efficiency Comparison - LED and Induction Lighting Fixtures[5] Lighting Fixture Type: 100W LED 100W Induction Model Number: XGB49 GTF-GCL-100 Nominal wattage (Watts): 100 W 100 W Ballast/Power Supply overhead (Watts): 18 W 3W Total actual wattage (Ballast/Power Supply included): 118 W 103 W Conversion efficiency (Lumens/Watt - lamp only): 71.4 L/W 78 L/W Light output (Manufacturers specifications in Lumens): 7,140 L 7,800 L Fixture Efficiency (Ballast/Power Supply included - Lumens/Watt): 55 L/W 75.7 L/W Actual Fixture Output (Lumens adjusted for Fixture Efficiency): 6,490 L 7,797 L Colour Rendering Index (CRI): 75 82 Colour Temperature (Kelvin): 6,500K 6,500K S/P Ratio (from chart): 2.25 2.25 Fixture Output corrected for VEL (VEL): 14,602 VEL* 17,543 VEL* Light output increase/decrease (%): 0% (Base) 17%* Energy savings (Watts / %): 0W / 0% (Base) 15W / 12.7% Energy cost for 100 hours operation (at $0.10/kWh $): $1.18 $1.03 Energy Cost per Year (24/7 operation at $0.10/kWh $): $103.37 $90.23 * Note: A difference of +/- 10 to 15% in light levels is barely perceptible to the human eye - VEL and % figures rounded up/ down to nearest whole number. Magnetic Induction Lamps Vs. LED Lights - Page 9
  11. 11. As we can see from the table (previous page) the Induction Lighting fixture produces 17% more light using 12.7% less electrical power, and has a higher CRI providing a more pleasant light with accurate colour rendering. If, for the sake of discussion, the area is well lit such that the additional 17% more light is unnecessary, one could consider using an 80W Induction Lamp fixture to increase energy savings as follows: Conversion Efficiency Comparison - LED and Induction Lighting Fixtures[5] Lighting Fixture Type: 100W LED 80W Induction Model Number: XGB49 GTF-GCL-80 Nominal wattage (Watts): 100 W 80 W Ballast/Power Supply overhead (Watts): 18 W 2W Total actual wattage (Ballast/Power Supply included): 118 W 82 W Conversion efficiency (Lumens/Watt - lamp only): 71.4 L/W 77.5 L/W Light output (Manufacturers specifications in Lumens): 7,140 L 8,250 L Fixture Efficiency (Ballast/Power Supply included - Lumens/Watt): 55 L/W 75.6 L/W Actual Fixture Output (Lumens adjusted for Fixture Efficiency): 6,490 L 6,199 L Colour Rendering Index (CRI): 75 82 Colour Temperature (Kelvin): 6,500K 6,500K S/P Ratio (from chart): 2.25 2.25 Fixture Output corrected for VEL (VEL): 14,602 VEL* 13,948 VEL* Light output increase/decrease (%): 0% (Base) - 4.5%* Energy savings (Watts / %): 0W / 0% (Base) 36W / 30.5% Energy cost for 100 hours operation (at $0.10/kWh $): $1.18 $0.82 Energy Cost per Year (24/7 Operation at $0.10/kWh $): $103.37 $71.83 * Note: A difference of +/- 10 to 15% in light levels is barely perceptible to the human eye - VEL and % figures rounded up/ down to nearest whole number. As previously mentioned, a light level of plus or minus 10% to 15% is barely perceptible to the human eye. Since the 80W Induction Fixture has a light output of only 4.5% less than the LED fixture, installing the 80W fixture will provide virtually the same light level, while saving 30.5% in energy costs! Lifespan and re-lamping: We have previously established, by means of the Lumen maintenance graph, that the high power LEDs reach 70% lumen depreciation at around 50,000 hours; while the External Inductor lamps reach the 70% line at around 85,000 hours. As discussed, this affects maintenance costs of the fixture for re-lamping or fixture replacement, and the labour associated with the work. Magnetic Induction Lamps Vs. LED Lights - Page 10
  12. 12. The table below provides the costs involved in Maintenance (re-lamping and labour) for the two fixture types. Having established that the light output level from an 80W Induction fixture is only 4.5% less than the LED fixture, an 80W Induction Light fixture could be installed Bear in mind that the maintenance costs for the 80W fixture will be the same as the 100W induction fixture due to lamp lifespan. Maintenance Comparison - LED and Induction Lighting Fixtures[5] Lighting Fixture Type: 100W LED 100W Induction Model Number: XGB49 GTF-GCL-100 Nominal Wattage (Watts): 100 W 100 W Manufacturers rated lamp life (Hours): 55,000 Hrs 95,000 Hrs Lamp life before replacement (at 70% Lumen Depreciation - Hours): 50,000 Hrs 85,000 Hrs 8 Years Maintenance analysis period (years); (70,080 Hrs of 24/7 operation) Number of lamp changes required during analysis period: 1 0 Cost of LED replacement “lamp” (fixture): $959.87* N/A Cost of replacement Induction Lamp and Ballast: N/A $169.95* Cost of re-lamping fixture (Electrician at $60/Hour): $30.00* $0.00* # Total Maintenance Costs over 8 years (Lamp and Labour) : $989.87* $0.00* Notes: * Prices shown are US Dollars (USD) - taxes not included. # Total maintenance costs do not include annual cleaning of the fixtures which can be done by means of drive-by power washing. A simulated underground parking garage prop on display at a trade show.[8] The display was designed to demonstrate the difference in light quality, colour rendering and energy consumption between conventional lighting technology (left) and Induction Lighting (right). The High CRI of the Induction Lighting provides better colour rendering. • Left: Lit by a 150W High Pressure Sodium (HPS) fixture (consuming 263 W of power) • Right: Lit by an 80W Induction Lighting fixture (consuming 86W of power ) Magnetic Induction Lamps Vs. LED Lights - Page 11
  13. 13. Total Cost of Ownership (TCO): When considering replacing conventional lighting fixtures with energy efficient lighting fixtures, one should consider Total Cost of Ownership (TCO). TCO takes into account the cost of the initial purchase and installation of the fixture, the cost of energy to operate the fixture, and the cost of maintenance (re-lamping and labour). In the table below we provide TCO data for 100W LED, 100W and 80W Induction, fixtures over an 8 years of 24/7 operation (typical in an underground garage), with power costs at $0.10 per kWh. Total Cost of Ownership (TCO) Comparison - LED and Induction Lighting Fixtures[5] 100W 80W Lighting Fixture Type: 100W LED Induction Induction Model Number: XGB49 GTF-GCL-100 GTF-GCL-80 Nominal Wattage (Watts): 100 W 100 W 80W Lifespan (from manufacturers specifications - Hrs): 55,000 Hrs 95,000 Hrs 95,000 Hrs 8 Years TCO analysis period (years); (70,080 Hrs of 24/7 operation) Conversion Efficiency (Light Output)* Fixture Efficiency (Ballast/Power Supply Included - L/W): 55 L/W 75.7 L/W 75.6 L/W Fixture Output (Lumens adjusted for fixture efficiency): 6,490 L 7,797 L 6, 199 L Colour Rendering Index (CRI) - S/P Ratio (from chart): 75 - 2.25 82 - 2.25 82 - 2.25 # Fixture output corrected for VEL (VEL): 14,602 VEL 17,543 VEL 13,948 VEL Light output increase/decrease (%): 0% (Base) + 16.8% - 4.5% Electricity Consumption and Power Costs* Fixture Power Consumption (Ballast/PSU included - W): 118W 103W 82W Power Consumption (Kilowatt/Hours - kWh): 0.118 kWh 0.103 kWh 0.082 kWh Power used in 8 years (70,080 Hrs, 24/7 operation - kWh) 8,269.44 kWh 7,218.24 kWh 5,746.56 kWh Cost of power used over 8 years (at $0.10/kWh): $826.94 $721.82 $574.65 # Total energy savings (%) : 0% (Base) 12.7% 30.5% $ Total Cost of Ownership (TCO) Cost of initial fixture purchase (Retail - $)$: $959.87 $279.95 $257.00 $ Cost of installation (.5 hours for electrician at $60/Hr) : $30.00 $30.00 $30.00 Maintenance costs over 8 years (Lamp & Labour)*~$: $959.87 $0.00 $0.00 $ Cost of power used over 8 years (at $0.10/kWh) : $826.94 $721.82 $574.65 Total Cost of Ownership (TCO) over 8 years$: $2,773.68 $1,031.77 $861.65 Total cost savings over 8 years$: 0% (Base) $1,741.91 $1,912.03 # Total energy and maintenance savings in 8 years (%) : 0% (Base) 62.8% 68.9% Notes: * From Previous tables # VEL rounded up/down to nearest whole number; Percentages shown to 1 decimal place $ Prices shown are in US Dollars (USD) - taxes not included. ~ Total maintenance costs do not include annual cleaning of the fixtures which can be done by means of drive-by power washing. Magnetic Induction Lamps Vs. LED Lights - Page 12
  14. 14. As we can see from the table (previous page), despite all of the hype about LED lighting, Magnetic Induction Lighting offers significant energy and cost savings. This example considered only one specific LED fixture - other comparisons will yield different results. Over time, it can be expected that both LED and Induction Lighting fixtures will continue to improve in conversion efficiency, and will fall in price. At present, Induction Lights offer the best options for new and replacement lighting fixtures which offer significant energy and maintenance savings (in the example 62%~68%) and much lower Total Cost of Ownership. Magnetic Induction Lighting is currently the most energy efficient and cost effective lighting on the planet! Environmental Considerations: The spectre of Global Warming (climate change), respect for the planet and reducing Co2 emissions, also play a role in making environmental choices about lighting. Since this is a detailed subject, we will give only a brief overview here. CO2 Emissions: Both LED and Induction Lamps offer a reduction in CO2 emissions from power generation. The exact amount will depend on the mix of fossil fuels used for power generation in the area where the fixtures are operating, and the total amount of energy saved. In the real-world example above, Induction Lighting offered more significant energy savings than LEDs thus offering greater CO2 reductions. In an increasing number of jurisdictions, organizations which reduce power consumption and the related Co2 emissions are eligible for “Carbon Credits”. The Carbon Credits can be used to offset other sectors within the organization that are not as efficient, or can be traded or sold. Toxic Substances: As with the manufacturing of any semiconductors, toxic chemicals are used in the fabrication of LEDs. Those of most concern are lead and arsenic as both are used in the process. However, the amounts present in finished LEDs are minute, usually fully encapsulated and should not cause any local contamination. Induction Lamps contain Mercury which is a toxic, persistent, bioaccumulative substance. Almost all modern lighting sources depend on using mercury inside the lamps for operation. When considering the environmental impact of the mercury in lighting, we must take into consideration: [a] The type of mercury (solid or liquid) which is present in the lamps; [b] The amount of mercury present in a particular type of lamp, and [c] The lifespan of the lamp which will determine the amount of mercury used during operation. Liquid mercury, which is the most common form of mercury used in HID and fluorescent lighting, represents the greatest environmental hazard. Mercury can be compounded with other metals, into a solid form called an amalgam - this is the type of mercury used in Magnetic Induction Lamps. It is similar to the once widely used amalgam in dental fillings. The solid form of mercury (amalgam) poses much less of an environmental problem than liquid mercury. Induction Lamps use the least amount of mercury of any lamp technology, when considered based on both initial quantity, and amount used over the lamp’s life. Magnetic Induction Lamps are more environmentally friendly since they use very little mercury over their lifespan. Further, the mercury is in solid amalgam form, reducing contamination in the case of breakage. The chart below shows the amount of mercury used in Induction lamps and other lighting technology based on consumption per 20,000 hours of operation: Magnetic Induction Lamps Vs. LED Lights - Page 13
  15. 15. Recycling: Once should also consider the environmental impact of the lighting once it has reached end-of- life. There is little information available on the recycling of LEDs. Since the LED lamps contain plastic and metals, theoretically the metal components could be recovered and recycled. In the case of Induction Lamps, The solid mercury amalgam can be recovered and recycled. Once the inductors are removed, the lamp body can be recycled as it is made of glass; while the inductors themselves can be recycled into their metal components.[9] OVERVIEW TABLE The table below summarises and compares the features of the two technologies using generalised statistics from various manufacturers. General Comparison of LED and Magnetic Induction Lamp Technologies Parameter White LED Lamps External Inductor Lamps 1 Lamp Sizes (wattages available) 100 mW to 20W 23W to 500W 35 to 70 L/W Conversion Efficiency 68 to 90 L/W (100 L/W reported in labs) Instant On? Yes Yes Starts at 80-85% of Starts at 100% of maximum light output Warm-Up Time maximum light output 90~270 seconds to reach 100% depending on wattage & model Dimmable? Yes (100% to 0%) Yes (100% to 50%) Hot Re-start (hot re-strike)? Yes Yes Ballast/Power Supply Overhead 5% to 15% 2% to 6% 2 Rated Lifespan 50,000 to 60,000 Hrs 80,500 to 100,000 Hrs 3 Lumen Depreciation to 70% Output 45,000 to 55,000 Hrs 80,000 to 90,000 Hrs Colour Temperature Range (CCT) 3,500K ~ 7,000K 3,500K ~ 6,500K Colour Rendering Index Range (CRI) CRI = 64~84 CRI = 80~85 S/P Ratio range 1.3 to 2.27 1.3 to 2.25 Average Mercury [Hg] Content (in Mg) 6.3~6.5 Mg N/A Mercury Type SOLID (no mercury content) Mercury use per 20,000 hours 1.3 mg Hg/20,000 Hrs 4 Energy Savings (%) 0 (Base) 50% ~ 68% (real-world example) 5 Energy Savings over HID Lighting (%) 20% to 50% 30% to 75% (High Pressure Sodium, & Metal Halide) NOTES: General - Percentage figures have been round up/down to the nearest whole number 1 - LED range includes small white LEDs used in indicator and flashlight applications 2 - From Manufacturers specification and data sheets 3 - From Lumen maintenance curves 4 - From previous tables 5 - Energy savings over HID lighting generalised. Actual savings will depend on the type/wattage of HID fixture replaced. Magnetic Induction Lamps Vs. LED Lights - Page 14
  16. 16. THE ADVANTAGES AND DISADVANTAGES OF LED LIGHTING Advantages: • Longer lifespan than other commercial/industrial lighting technologies - between 50,000 and 60,000 hours for high output types; • Higher energy conversion efficiencies (than most other commercial/industrial lighting) of between 35 and 70 Lumens/watt [efficiencies in the 100 L/W range have been demonstrated in labs but are not yet commercially available]; • Lower ballast overhead than conventional commercial/industrial lighting technologies due to the electronic power supply which is more efficient than “core & coil” types; • Instant-on and hot re-strike, unlike most conventional HID (high intensity discharge) lamps presently used in commercial/industrial lighting; • Small form-factor makes them ideal for compact applications such as signage or traffic signals; • Very rugged making LEDs ideal for use in high vibration industrial and transport applications. Disadvantages: • Shorter life-span compared to Induction Lighting; • An expensive technology that may not provide good Return On Investment in many applications. THE ADVANTAGES AND DISADVANTAGES OF INDUCTION LAMPS Advantages: • Bright, pleasant, broad-source. flicker-free lamp with less glare than conventional lighting - high CRI for excellent color rendering; • Extremely long lifespan due to sealed construction and the lack of electrodes - between 85,000 and 100,000 hours depending on the lamp type and model; • Very high energy conversion efficiencies of between 68 and 90 Lumens/watt [higher wattage lamps are more energy efficient]; • Low power factor due to the high frequency electronic ballasts which are 95% to 98% efficient; • Minimal Lumen depreciation (declining light output over time) compared to all other lamp types - lifespan of external inductor type is 80,000 to 90,000 hours of operation before they reach 70% lumen depreciation; • Instant-on and hot re-strike, unlike most conventional HID (high intensity discharge) lamps presently used in commercial/industrial lighting applications; • Medium ruggedness - More rugged that many types of commercial/industrial lighting. Can be used in industrial settings with moderate vibrations. Induction lamps have been used in transportation applications such a lighting on trains and ships. • Environmentally friendly as Magnetic Induction Lamps use less energy, and generally use less mercury per hour of operation, that conventional lighting due to their long lifespan. Can be disassembled for mercury, metals and glass recycling at end-of-life (see Environmental Aspects Of Magnetic Induction Lamps[9] Disadvantages: • Larger form-factor than other commercial/industrial lighting (not suitable for applications requiring compact light sources); • Contains solid Mercury amalgam. Magnetic Induction Lamps Vs. LED Lights - Page 15
  17. 17. SUMMARY While LED lighting is an energy saving alternative when replacing HID lighting fixtures, and shows great promise as the technology evolves, it is presently costly to implement, has a much shorter lifespan than Induction Lamps and a higher TCO. Magnetic Induction Lighting is currently the best choice for energy and cost savings in most commercial and industrial lighting applications as we have demonstrated. Induction lighting has a low cost of acquisition, offers greater energy and maintenance savings, has a low TCO and a high Return On Investment (ROI). REFERENCES: 1] For more information on how Magnetic Induction Lamps work, see work# 2] Performance of phosphor-coated LED optics in ray trace simulations - Proceedings of SPIE, Vol. 5530, 266 (2004) 3] Energy Efficient Lighting in Industry - European Commission Directorate-General for Energy 4] “Despite Different Wall Colours, Vertical Scotopic Illuminance Predicts Pupil Size”, S. M. Berman, D. L. Jewett, B. R. Benson and T. M. Law - Journal of the Illumination Engineering Society 26 (No. 2) 1997 available at PDF/Archives/2003_02.pdf 5] From Manufacturers specifications and data sheets 6] Epistar achieves 80 lm/W warm white LED - LEDs Review, September 7, 2009 7] Operations and Maintenance Manual for Energy Management, By James E. Piper - Published by M.E. Sharpe, ISBN 0765600501, 9780765600509 8] Photo Courtesy of GreenTech Fixtures Inc. 9] For a more detailed discussion, of environmental considerations relating to Magnetic Induction LIghting, see the Knol article: ABOUT THE AUTHOR: L. MICHAEL ROBERTS L. Michael Roberts, is an author, consultant and inventor who holds patents in UV water purification technology and also has a number of patents pending in Magnetic Induction Lighting technology. He is the Chief Technical Officer of InduLux Technologies Inc, in Goderich, Canada - where he is responsible for the development of advanced energy saving fixtures. InduLux designs are then licensed to manufacturers for production. The photo shows him holding a prototype 20W, self-ballasted, magnetic induction lamp that produces 20% more light than the same wattage of compact florescent lamp, and will last for 60,000 hours of operation. For More Information Please Contact: GreenTech Fixtures Inc. 56 Stanley Street, Goderich, Ontario, Canada N7A 3K5 Tel: 519-955-4354 Fax: 519-524-8416 Magnetic Induction Lamps Vs. LED Lights - Page 16