Magnetic Induction Lamps Principal & Environmental Benefits
- Lighting and the Environment
- Electrical Conversion Efficiency
- Understanding Apparent Brightness
- Understanding Visually Effective Lumens
- Primary VEL Design & Energy Consumption Benefits
- Secondary Design and Energy Consumption Factors
- Thermal Loads
- On-Demand Usage
- Environmental Resources Consumption Considerations
- Mercury Utilization
- Recycling Considerations
Lighting and the Environment
Global Warming is a growing concern and there is a heightened desire to reduce our environmental footprint. In many cases, the technology to do so is readily available but often too expensive to implement.
For example, pollution scrubbing technology used for factory smokestacks while available, is costly, disruptive to install, and in some cases may consume more energy (thereby actually adding to carbon output from energy production) than the environmental remediation benefits it offers. On the other hand electrodeless magnetic induction lamps are a cost effective way to implement an environmentally friendly technology while also reducing environmental impact in several areas.
As you’ll learn here; we’ll consider reducing electrical energy use in lighting and its attendant reduction of C02 production from power generation; secondary energy reduction through lower thermal loads in buildings; reduction of material usage and manufacturing energy; and reduction of mercury content and its impact on the environment by the use of induction lighting products and controls.[back to top]
Electrical Conversion Efficiency
Electrical conversion efficiency (sometimes stated as conversion efficiency) is a measure of how well a lamp converts electrical energy into light. The conversion efficiency is stated in Lumens per Watt (L/W) and is usually in a range since there is some economy of scale where higher wattage lamps tend to have better conversion efficiencies than lower wattage lamps of the same type.
For example, the common incandescent lamps we are all used to, generally have a conversion efficiency of between 12.5 and 19 lumens per watt. Induction lamps have conversion efficiencies in the 70 to 84 Lumens/Watt range. This means you get more light output for the same amount of energy input, or, stated another way, the same amount of light (when comparing lumen output) for less energy input.
We’ll go into more detailed design issues in the next section. But for the purpose of the energy consumption when dealing with the side by side comparisons of various lamp types the induction lamp will deliver the perceived light levels at 50% less of its alternatives.[back to top]
Understanding Apparent Brightness
There is wide agreement and scientific data that shows how the spectral distribution of the light produced by a particular lamp affects human vision and plant growth differently. 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 lamps spectral output of light that is useful to the human eye is also a factor in perceived light quality and brightness or a phenomenon known as Apparent Brightness while plants require narrower bands of ultraviolet and infrared that maximize chlorophyll absorption specific for the plants stage of growth development. This measurement is known as photosynthetic active radiation or PAR for short.
There are two types of lumen output which the human eye can perceive. The first being photopic and the cones within our eyes see this light in daylight values as measured in Lumen, Lux or Foot Candles. Utilizing conventional lighting design we would factor the project’s Design Lumens, in photopic values only and measured with a standard light meter.
The second type of lumens are called Scotopic, which represents the sensitivity of the eye under typical interior or night lighting conditions and cannot be measured directly with a standard light meter. Scotopic lumen output is registered by the rods of the human eye and also controls pupil size directly effecting visual acuity for given task levels.[back to top]
Understanding Visually Effective Lumens (VEL)
While there is currently no scientific or an industry wide consensus for a terminology to describe the Apparent Brightness phenomenon, there is growing use of the term Visually Effective Lumens (VEL) or Pupil Lumens as a way to not only describe it but to accurately measure these levels as well.
As we discussed earlier, the conventional lighting design recognizes the photopic lumen output values only. To gain the complete benefits of a lamps VEL values it becomes necessary to adjust the photopic values during the design standard since the minimum lumens normally associated with a given task (LUX = Lumens per sq/ft) or Foot Candles (FC) values.
Design levels, as you’ll see a bit later here, that only rely on a lamps FC or LUX are much less energy efficient since they do not take into consideration the additional light output and it’s Apparent Brightness when factoring that lamps Scotopic lumen output and upwardly adjusting the lumen output within the VEL values.
The VEL of a lamp can be determined by multiplying the output in lumens by a conversion factor. The conversion factors are derived from the Scotopic/Photopic Ratio (S/P ratio) of a lamp. The S/P ratio measure the amount of light being output in the Photopic sensitivity region, and the amount of light output in the Scotopic sensitivity region, of the human eye, and then derives the ratio of the two.
When the ratio is used as a multiplier of the actual output lumens, the amount of light useful to the human eye (VEL) can be determined. For example, a 100 Watt incandescent lamp with a conversion efficiency of 30 L/W provides 3,000 Lumens of light – multiplied by it’s S/P ratio of 1.4, it is producing 4,230 VEL – light useful to human vision. The S/P ratio correction factor drastically changes the conversion efficiency of the lamps.
The lamp type which has the highest conversion efficiency, Low Pressure Sodium (SOX) at 100~180 L/W, is now one of the least efficient light sources at 35~63 L/W when corrected for S/P ratio. This is because the SOX lamps produce nearly monochromatic yellow light. While they score high on the Photopic curve (where conversion efficiencies are measured), they score low when corrected for VEL due to lack of blue output. SOX lamps are an excellent example of why these conversions our useful for a more accurate measurement relative human vision or plant spectra.
The induction lamps have the highest energy conversion efficiency once the correction factor is applied (as they have a high S/P ratio of 1.96 or 2.25 depending on model). Induction lamps are therefore a better choice as they produce more light useful to the plant while using less electrical energy.
With this information in mind we can now compare light sources, based on the actual amount of VEL which they produce.[back to top]
Primary VEL Design & Energy Consumption Benefits
Chart 1 shows how different light sources Design Lumen readings compare when read by a standard light meter and measured in Conventional Photopic Lumen values. For lighting design that wishes to maximize energy efficiencies by specifying light sources with both high Scotopic and Photopic Lumens, a Correction Factor (S&P Ratio) must be applied to the Photopic Lumen per Watt readings. When applying this correction factor you will notice drastically different usable light outputs as measured in VEL. Higher VEL/W will significantly reduce the amount of energy necessary to satisfy the plants lighting requirements.
|1 - Measuring Energy Efficiency
|Induction Lamp (5000K)||85||1.96||166.6|
|Warm White Fluorescent (2900K)||65||0.98||64|
Chart 2 shows actual Photopic and Scotopic Values with different lamp types and how bright they appear to the eye. This perceived value is known as Apparent Brightness and is not measured in the conventional Lumens, Lux or Foot Candle readings. Apparent Brightness is then measured in Visually Effective Lumens (VEL). Induction VEL values are much higher at lower wattages than the HID lamps.
|2 - Apparent Brightness||Wattage||Photopic Value||Scotopic Value||VEL|
|High Pressure Sodium||150 w||11,250||8,550||9,082|
|Metal Halide (Pulse Start)||150 w||8,000||11,920||10,919|
Secondary Design and Energy Consumption Factors
Ballast Overhead: An additional factor which must be taken into account when considering lighting fixture energy consumption is ballast overhead. Almost all modern, high output lighting systems, use some form of ballast to control the energy provided to the lamp. The two most common types of ballast are the so-called core & coil ballasts and electronic ballasts.
- The core and coil ballasts use coils of copper wire wound around an iron core to form a special purpose transformer which controls the electrical energy provided to the lamp. The ballast may have additional components which perform other functions such as a starter circuit. The core and coil ballasts typically consume between 10% and 15% of the energy fed to the lighting fixture. This is wasted energy that usually just produces heat and detracts from the efficiency of the lighting fixtures.
- Electronic ballasts perform the same function of controlling the energy fed to the lamp and providing a start pulse if required, but they do this using electronic components rather then a transformer type ballast. As a result, they are very efficient since they can use active feedback control and a microprocessor to keep the lamp within correct operating parameters. In the case of the electronic ballasts used for induction lamps, only 2% of the total system energy is lost on the ballast. When we take ballast overhead into account, the induction lamps have significantly lower losses than most conventional lighting.
Electricity Production and CO2 Emissions: Carbon Dioxide (CO2) is a greenhouse gas which traps solar radiation (heat) in the Earth’s atmosphere increasing global warming and climate change. In North America, average electrical power generation is 71% from fossil fuels [coal and gas] and 26% from fossil fuels in Canada. Most of the CO2 emissions in the USA are from the generation of electricity.
Burning fossil fuels to generate electricity emits C02 into the atmosphere. Figures for the amount of CO2 emitted per Kilowatt hour of electricity generated vary from .612 Kg/KWh (1.35 Lbs/KWh) in the USA. These figures can vary widely depending on the mix of fossil fuel and other types of generating plants in use. For the purpose of this paper, we will use an average figure of 0.43 Kg/KWh (0.95 Lbs/KWh) in our discussions although the reader should bear in mind that this figure will be higher in the USA due to extensive use of coal. By reducing electrical power consumption, we not only save money, but we also reduce the emission of CO2 into the atmosphere from power generating stations.
Based on operating the lighting fixtures 24/7 for one year, replacing the Metal Halide lamp fixture with an induction lamp fixture will reduce CO2 emissions from electrical power generation by 1,270 Lbs or about 55%. Again, this is the figure for one fixture and typically there will be dozens or even hundreds of fixtures in a facility¦ thousands when considering a city or region. Replacing inefficient lighting technologies with energy efficient Induction lamps, can contribute to significant energy consumption savings and CO2 emissions reduction.
The primary mode of energy reduction from replacing conventional lighting with energy efficient lighting fixtures is the energy savings on electrical consumption. However there are also other ways that energy efficient Induction lamps can reduce energy consumption and its attendant environmental impact.[back to top]
The Ballast overhead, which we discussed earlier, represents the loss of electrical energy in the ballast. This lost energy manifests primarily as heat, which is added to the heat output by the lamp itself. This heat output is the thermal load contribution of the fixture or the amount of heat it contributes to the space in which it is operating.
The 250W Metal Halide lamp we have been using as an example, will contribute 25W or more of heat (for each fixture) to the space it is operating in. In effect, each lighting fixture becomes a 25W [or more depending on the heat output from the lamp] radiant heater.
In winter conditions, when the space must be heated, this is a welcome contribution and represents energy that can be used. In spaces which are air-conditioned, the thermal load of the lighting represents additional heat that must be removed by the HVAC system with adds to energy consumption. While this is, generally speaking, a small amount of heat, in applications such as cold-storage facilities or commercial/industrial freezers, the thermal load from lighting can represent a significant fraction of cooling costs.
By installing Induction lamps with efficient electronic ballasts, where both the ballasts and the lamps operate at lower temperatures than Metal Halide or High Pressure Sodium fixtures, there are secondary energy savings to be gained from the reduced heat load produced by the induction lighting fixtures.[back to top]
In some applications, for example an infrequently visited section of a warehouse or storage facility, the management must keep Metal Halide and High Pressure Sodium fixtures operating continuously. These types of fixtures (and almost all other high-light-output fixtures) are not designed for instant on or multiple on/off switching of the fixture. These lamps require some time to warm up to full output. Therefore it is impractical and inconvenient to turn them off in applications where the usage is predicated on staff activity, since people entering the area will have to wait 5 to 15 minutes for this type of lighting to reach full output. >
On the other hand Induction lamps are considered instant-on since they typically start operating at around 80% of maximum light output, and reach 100% of output in a very short time (90 to 240 seconds depending on the model).
Indoor grow applications that may utilize solar tube or skylighting systems for indoor lighting contribution may elect to switch off the Inda-Gro fixtures when the outside light levels are measured high enough for the task levels thereby further reducing thermal load as the lights are only operated as needed. This can be a significant energy savings when compared to MH or HPS fixtures operating continuously in a similar application and require the cooling systems to overcome their thermal contributions.[back to top]
Environmental Resources Consumption Considerations
All lighting fixtures require resources of material and energy to manufacture. Since it is almost impossible to find figures for the resources and energy required to manufacture lamps and lighting fixtures, let us consider only the resources entailed in manufacturing replacement lamps.
When a lamp is first struck on it will be producing the most lumens it is capable of. This lumen output is known as the lamps Initial Lumen Output. From this point a lamps lumen output reduces as it ages. This reduction in lumen output known as the lamps Lumen maintenance and is a measure of how well a lamp type maintains its light output over time.
While Lumen Depreciation occurs in all lamps as they age, lumen depreciation levels over the lamp life can vary between a 70% loss of lumen output (HID lamps) to no more then 30% (induction) of their initial lumen output.
The information for Lumen depreciation is usually published as Lumen maintenance curves. The lumen depreciation of a lamp type will determine how often it must be replaced. Experts recommend that lamps should be replaced once they have depreciated to 70% of their initial output. 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. Once the light output from any lamp falls below 70% of initial output, it is considered due replacement.
MH and HPS lamps will require far more frequent lamp replacement than the Induction lamps. If, for the sake of simplifying the example, we presume that the amount of energy and materials needed to manufacture one of each kind of lamp is the same, then we can see that using MH lamps consumes 8.7 times the resources, and the HPS lamp consume 5.8 times the resources, compared to the materials and manufacturing resources for an induction lamp. Induction lamps therefore conserve resources and reduce waste due to their long lifespan.
Those materials have to go somewhere once any lamp reaches end of life. While expired lamps used in industrial/commercial applications typically end up in the landfills, much of the materials in the lamps, such as the glass and metals, can be recovered and recycled.[back to top]
Almost all modern high output light sources depend on using mercury inside the lamps for operation. When considering the environmental impact of the mercury in lighting, we must take three factors into consideration:
- The type of mercury (solid or liquid) which is present in the lamps,
- The amount of mercury present in a particular type of lamp, and
- The lifespan of the lamp which will determine the amount of mercury used per hour of operation.
Liquid mercury, which is the most common form of mercury used in lighting, represents the greatest hazard. If a lamp is broken, the liquid mercury can find its way into cracks in concrete flooring, the fibers of carpets, or into spaces in other floor coverings. Over time, the mercury will evaporate into the atmosphere causing a local hot spot of low level contamination. The more liquid mercury present in a lamp, the longer the resulting contamination will last.
Mercury can be compounded with other metals, into a solid form called an amalgam – this is the type of mercury used in induction lamps. It is similar to the once widely used dental amalgam in tooth fillings. The solid form of mercury poses much less of an environmental problem than liquid mercury. The small slug of amalgam can easily be recovered (always wear disposable gloves) in the case of induction lamp breakage and therefore can be disposed of properly with little or no risk of creating a locally contaminated area. The solid mercury amalgam is also simpler to recover for recycling at end of lamp life.
A pellet of Mercury amalgam can be seen in the glass “fill tube” of a typical round induction lamp. The silver object at the bottom left of the picture is one of the external inductors. This is easily broken off and recycled.
|Lamp type||Low Pressure Sodium (SOX)||High Pressure Sodium (HPS)||Metal Halide||48" Fluorescent tube||Induction Lamps|
|Average Mercury (Hg) Content (in mg||GE: 6-8
Phillips low Hg: 10-12
|Miser: 6.4 mg|
|Mercury use per 20,000 hours ||12.4 mg Hg||14.3 mg Hg||37.8 mg Hg||27.6 mg Hg||1.3 mg Hg|
Induction lamps use the least amount of mercury of any lamp technology, when considered based on both initial quantity and amount used per 20,000 hours of lamp life. Induction lamps are therefore much 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 accidental breakage and making recovery for recycling simpler.[back to top]
As mentioned above, induction lamps require much less resources, in terms of the raw materials for manufacturing, than other lamp technologies considering the long lifespan of the lamps, and the number of replacement lamps required by competing technologies. LED circuit boards cannot be easily recycled and can also be expensive to dispose of.
Further, induction lamps are simpler and cheaper to recycle. The solid mercury amalgam is easily removed and can be recycled with little chance of environmental contamination. The external or internal inductors can be removed (for metal recovery) leaving a glass envelope free of metal parts which takes less energy to recycle. Competing lamp technologies have a significant amount of metal embedded in the lamp envelopes, thus higher temperatures and more energy must be expended to recycle the components.[back to top]
Like you we at Inda-Gro firmly believe reducing our environmental impact and carbon footprint are worthy goals which can make a difference in limiting global warming and climate change. Lighting consumes a significant fraction of energy production with its attendant CO2 emissions. By installing energy efficient lighting systems, you can not only reduce energy costs and expenditures, but also reduce environmental impact through reduced CO2 emissions from electrical generation, reduced waste and improved recycling.
When comparing various lighting technologies used in industrial, manufacturing. retail and grow applications, it becomes clear that induction lamp based lighting fixtures offer the best environmental characteristics when compared to the most commonly used lighting technologies.
When compared to the two most commonly used lighting technologies (Metal Halide and High Pressure Sodium lamps), Induction lamps offer the following benefits:
- Significant reduction of electrical energy consumption;
- More light output when corrected for Visually Effective Lumens/Pupil Lumens;
- Significant reduction in CO2 emissions from electrical power generation due to reduced energy consumption;
- Secondary energy consumption reduction through reduced thermal loads thereby saving HVAC costs and energy, and the ability to use on-demand technologies such as occupancy sensors due to the instant on feature of induction lamps;
- Extended lifespan which reduces the materials needed for replacement lamps compared to MH, HPS and SOX lighting technology; 1.5-2 times the lifespan of LED
- Low mercury consumption over the induction lamp lifespan compared to competing lighting technologies;
- Induction lamps use a solid mercury amalgam which produces significantly little environmental impact compared to other technologies, if accidentally broken. The solid mercury amalgam is also easy to recover and recycle at the end of lamp life; and
- End of life de-construction for recycling and materials recovery requires less energy.
Magnetic Induction Lamps represent not only a breakthrough in cost effective energy efficient lighting, but also a sound environmental choice, when all aspects of the lamp technology are considered.[back to top]