LED leading the Future By Thomas DeSantos, P.E.

The future of lighting is as clear and focused as the choice itself, Light Emitting Diodes (LED). What remains a mystery is when, where, and how appropriate standards will be put in place to allow them to achieve their destiny, the most effective and desirable light source on the market. LED Lighting Solutions, LLC has prepared this article to draw attention to pertinent facts and advantages of LED technology, as well as the sharp bias of the current Industry Standards for measuring the effectiveness of a light source.

Why are LED's the Superior Technology? - LED's are competing on an uneven playing field tilted completely against the technological advantage they provide, and yet they still outshine all other light sources. The reason is because LED are designed for the time of day that artificial light was originally invented for, the NIGHT. LED, as a lighting source, is unique in many ways, each making it the superior technology.

Most Efficient Light Source - LED technology produces light as a direct result of the process itself. All other artificial light source technologies such as incandescent bulbs, compact fluorescents (cfls), metal halide, high pressure sodium (HPS), etc. create light as a byproduct of another process of burning chemicals.
Incandescent lights produce light as the byproduct of the heat off the filament inside the bulb. Fluorescents (standard T5/T8 tubes and CFL), metal halides, high pressure sodium, etc. create light via an electro-chemical reaction, or chemo luminescence, to produce light as the byproduct of the chemical burn.
LED lights are made from semi-conducting material, and when energy is passed between two semiconductors light is produced in a process known as electroluminescence. The color of the light can then easily be varied by changing the semiconducting material.

Focused - LED technology is a focused light. LED can be directed where light is needed for a uniform distribution. By comparison, traditional light sources are only capable of one blast of light directly beneath the light source. This is evident in Photo 2, showing the HPS lighting that existed prior to the LED light installed to improve conditions. This is why light sources are frequently installed on massive poles as high as 100 feet on highways, fishing piers, and ball
fields. Other light sources need to go that high to try and spread the distribution of their light. With LED, we can direct light in a focused fashion out as far as 45 feet at elevations as low as 7 feet from the ground, for example as in parking garages. Thus, LED can get distribution patterns that are exponentially more uniform. In stark contrast to the 100 foot mounting height of highways and ball fields for other light technologies, LED can provide better quality and distribution of light at heights of 30 feet, and with energy savings of greater than 90%!

LED Lighting Solutions, LLC recently upgraded a property management headquarters to LED. They were using 400 watt metal halide lights drawing 460 watts of plug power. We replaced that with our 40w LED using 40 plug watts. As an engineer, I was afraid the analysis was not going to match the real world. I was skeptical that the 93% energy reduction we were predicting would actually match the existing lighting levels.
The night after we installed the 40w LED, I got a call from the Facility Manager. He said he had just called the Owner, who had left after dark, to see what he had thought of the new lights. He said "I didn't even notice". That bolstered my confidence to talk with the Office Manager to get her opinion of the light upgrade. She said "It's tremendous. I can find my keyhole at night now".

Note: The most efficient light in the world at 99 lm/w, was used in this case. It is literally 50% more efficient than most LED competitors.

The Color of Night - Remember when trees didn't look yellow at night? I don't. I cannot recall ever seeing the green colors of spring at night. I was recently told that the old mercury vapor lights allowed the showing of the greenness, but those certainly aren't environmentally friendly products as they contain mercury similar to the fluorescents. Note the street light below which uses LED Cobra heads to provide a high quality light source, as well as the focus of the LED in preventing light pollution to the environment and neighboring properties.

Wakeup and Concentrate! - A recent article in the New York Times "In Eyes, a Clock Calibrated by Wavelengths of Light" , by LAURA BEIL, Published: July 4, 2011 stated the importance that light temperature can mean to alertness levels and concentration. The article discussed a study by the University of Basel in Switzerland that had tested 13 individuals using fluorescent lighting vs. LED.

Participants were tested with cognitive functions using fluorescent lighting vs. LED. The study results showed that the melatonin levels, which induce sleep, were much lower when the subjects used the LED. In other words, they were more alert. Furthermore, "the subjects also scored higher on tests of memory and cognition after exposure to blue light provided by the LED." This small scale test would indicate that more investigation should be done on LED to choose the optimum color for lighting streets, headlights, sites, schools, offices, etc.

Light Designed for Night - LED is the superior technology…simply because it is the ONLY artificial light source that produces light for both day and night vision, photopic and scotopic light, respectively. The combination of the two factors in dusk, or nighttime conditions is called Mesopic vision. The light that falls in this range is below 0.3 fc. All other artificial light sources produce only the photopic lumens visible to the cones of the eyes. The scotopic lumens are all that is currently recognized for lighting standards.

The proof of all these superior factors is shown below, where we upgraded a hotel parking garage. Note how most of these factors show up quite clearly in the photo, as

1. Efficiency (Replaced 200w metal halide with 30w LED providing an 85% energy savings) 2. Focused (Note the original fixture put one blast of light directly beneath the fixture… nothing 10 feet away) 3. Color of the night (You can see the colors of the vehicles after the upgrade) 4. Wakeup and Concentrate (not easily shown in a photo, though I couldn't read a tape measure standing beneath the old fixtures and could now read a novel under the LED) 5. Light Designed for Night (What was once dark is now daylight)

The Unenlightened - The source of the confusion starts with the design standards, methods of measurement, regulatory requirements, and even incentives. Reviewers only know what they are told by those in authority and thus far the standards have not yet been created or accepted.
This same inaccuracy is carried forward in the current lighting analysis methods. A typical analysis based on lumens show that the size light required is likely to draw 3 times the energy demand of that is needed to equate to traditional light source foot candles.
Even with this handicap applied, the LED still can match the lumens while reducing the energy demand by greater than 50%. But if you were to also compare the light's total lumens to total lumens, the LED's would actually be 70 to 95% more efficient. This is demonstrated in the parking garage upgrade LED Lighting Solutions did for a 5 Star Hotel in Cromwell CT, where we achieved an 85% energy reduction.

Blinded by Ignorance - A recent conference focusing on establishing a national municipal ordinance on lighting was another eye opener on the bias and uniformed status of the authorities. The event highlighted their lack of understanding of LED.
First, they proposed to base a new light standard on lumens. This was upsetting, as I had just shown the individual presenting this new standard the importance of the scotopic lumens. Then they proposed to add an arbitrary penalty on LED to require more lumens. This "penalty" thinking is exactly my frustration! I forget the reasoning behind this "penalty", but they couldn't make the process more complicated and erroneous. My suggestion to have them refer to the International Electrical Society for minimum standards based on foot candles until a mesopic function could be accepted was unappreciated. This lack of consideration was likely because it would have canned the entire 12 page document their organization had created to simply the national municipal lighting standards. Plus, why let facts get in the way of a good argument.

The same group alerted me to the New York Times link that discusses the bluish light of LED keeping people more alert at night. This too I found underlined their grasp of the technology. The comment was:

"From a human health standpoint, LED streetlights in the bluish range can become an adverse health factor, if the research in the story holds – particularly in settings where streetlight illumination enters windows of residential houses or apartments. Specifying LEDs with warmer CCT values (2,800 to 4,000) may offer a health benefit over LEDs in the bluish or bluish-white range..."

:Because, who would want the drivers to be awake at the wheel, right? My thoughts are that when my town upgrades to LED, I am going to need to buy a bunch of night lights. I currently use a 250w HPS street light to navigate my house at night.

Uneveness
This lack of understanding from the regulators then translates to unevenness with rebate programs as well, as their criteria are based on the scotopic lumens.
For example, consider a simple 2'x2' recessed grill fixture (troffer) for comparison. The Design Light Consortium rebate program has a specific category for this fixture type that many other lights can receive rebates for. It would seem like a natural fit for a high-performance LED lamp to qualify However when a NVLAP approved test lab conducted testing on a 2' x 2' troffer consisting of (3) 8 watt LED T8 bulb/fixture combo, their findings were that the fixture failed testing as the replacement for the standard 2 x 2 CFL fixture because the LED's were only producing 2,400 lumens, and the standard for listing on Design Lights Consortium requires a minimum of 3,200 lumens. The fixture would have to be "over-lit" to meet the standards, when your eyes tell you that 3 tubes would be the equivalent. This is a key factor in driving the cost of the bulb/fixture combo beyond what the rebates would provide and without rebates makes LED even pricier. It would also give LED a reputation for causing glare, because they might appear to be too bright, even if the meters told you the lumens were the same.
Seeing the Light
One of the most light-sensitive facilities, the Museum of Fine Arts performed an analysis considering both the photopic and scotopic lumens, by measuring the performance in place using foot candles. They found that (2) 17 watt LED bulbs could replace (3) conventional fluorescent 96w bulbs, with ballasts drawing another 24w, for an 82% reduction in energy. These lights are used 24/7, so the payback without rebates (because there currently are none for the LED tube lights) at their current electricity rate of $0.13/kwh is less than 10 months.
Furthermore, when they upgrade just their entire 4 foot T8 collection, which is 10,000, they'll save over $6M in energy and another $2M in maintenance and operation. They also save an additional 20% in their air conditioning costs due to the reduced thermal output from the lamps. All while reducing their carbon emissions by over 36,000 tons.

Progress - Since I first wrote this paper 12 months ago, some progress has been made. Design Lights Consortium (DLC) has become the "Energy Star" for commercial lighting and has taken on the task of providing standards for LED.
Currently, DLC is still using lumens to compare LED products. However, they do have performance criteria and standards that weeds out some of the LED products that could give the technology a bad name. Their criteria begin with NVLAP labs approved to be independent 3rd party testing facilities. There are about 8 companies allowed to do this testing. Some of the DLC criteria include:
 LM79 tests, which test several parameters , including:
o Efficacy of the product, or Efficiency of the light. For example, some manufacturers call their light a 100w light. However, that is just the number of LED they use. They might actually use 198 watts.
o CRI or Color Rendering Index of the LED
o Insitu testing, or the temperature the product runs at
o Photometric parameters, including a BUG rating system to test the backlight, uplight, and glare of the product. This is important as I've tried to sell some people that have bought other LED on the fact that the glare the experienced with their other manufacturer is not normal. Being rated by the DLC gives credence to the fact that not all are created equal.
 LM80 tests, which measures the life span of the LED

While the DLC system is not yet perfect, it at least provides some standards and direction for the technology. Additionally, the former DLC review agent directed me to research that was developed for a system of mesopic photometry, as they understood the conundrum.
Studies were developed to ascertain a more realistic comparison of photopic lumens vs. the photopic and scotopic lumens LED provide. They each developed similar differential equations to correlate the LED lumens to the levels the eye perceives. My Calculus 4 skills have eroded since my college days, so I wasn't able to test the theories myself. However, if one of the equations was accepted by the DLC or IES, then a simple program to run the function.

The hope is that the DLC, International Electrical Society, and others will move quickly to adopt standards that fully capture the brilliance of the LED's, and level the playing field. Then they will fully take their place as the premier light source that they are. The potential cost implications to correctly correlate the LED would be staggering and be a catalyst for the transition to LED.