July 7, 2007
Lighting: Choice is ImportantBy Justin Cody
First off let me say that I work for an electrical contractor that is part of an energy conservation program with United Illuminating (one of Connecticut's two big utility companies). I am not beholden to any particular manufacturer or type of lighting. My job is to save a commercial or industrial business energy on the lighting portion of their electrical bill regardless of what lighting technology is used and also to preserve or improve current lighting conditions; these businesses also include churches and other non-profits that get hit hard by the rising cost of energy due to some factors of how deregulation was handled.
General Lighting Terms and Definitions
Lumen & Lumen/Watt: A lumen is a measure of light output: Lumen/Watt is a measure of efficiency
Foot Candles: Measure of Light at a distance of 1 foot from the source.
Point Source: Light type that is bright at the point of emission, but does not cast light at a distance (Low efficiency LEDs and Automotive LEDs)
Punch/Throw: The ability of a light fixture or technology to deliver more of the light to the intended target or area.
Beam Angle: The degree angle at which the light is disbursed over a target or area.
Kelving/Burning Temperature: The metric which tells one the color of the lamp: related to the burning of a tungsten filament and the correlated color.
Solid State: Light Emitting Diodes and Light Emitting capacitor Technologies featuring non-volatile integrated circuit based lighting.
Incandescent: Burning of a sealed filament
HID: High Intensity Discharge: A type of lighting where the light is generated by arcing an electrical charge between two electrodes (Variations include Metal Halide and High Pressure Sodium and Xenon Doped)
Fluorescent: A type of lighting technology involving a glass enclosure with mercury vapor spread by negative pressure and and electrical charge causing the illumination of various phosphors.
Ballast: The device or driver which regulates the amperage and voltage delivered to the lamps, increasing or decreasing their illumination.
Compact Fluorescent lamps, when they first came out, were expensive; came in one ugly color, and produced very little light, and by and large were undesirable by the general populace. Companies that produce CFLs have made tremendous strides in technology in the years since they first appeared. I recently attended Lightfair International at the Javits Center in New York City. Fluorescent technology has hit its golden age it would seem. There were fluorescent lamps there of every color imaginable and even more importantly to some...in designs that were not the typical curly queue.
MaxLite is one company that makes a "mini-globe" Fluorescent that looks very much like your frosted 60watt incandescent. Others will soon be coming out with similar versions soon.
Compact Fluorescent lamps are several times brighter now than in the past, come in many colors and over time will use less and less mercury as other methods such as argon doping become available. They come in outdoor enclosed flavors as well and for some additional money you can get CFL's with dimmable ballasts allowing them to be used on dimmer switches. Comapct Fluorescent lamps generally last longer than incandescents, but if your area gets frequent spikes or surges of electrical energy this will likely result in a shorter life of the lamp. Dimmer switches also reduce the life rating from 10,000 hours to about 8,000 hours.
Fluorescents without an enclosure do not operate well in cold temperatures, but with a vapor-tight (weather proof) enclosure they produce enough heat on their own to operate down to about -40 degrees Fahrenheit.
Newer Super-T8 four foot fluorescent tubes use less than 2mg of mercury vapor, but as a result will put out less lumen than the current T-8 technology
CFLs and all Fluorescent Lights also produce a measure of UV radiation when lit (yes it is possible to get a sun burn) and fluorescent lamps can fade carpet, artwork and any sensitive dyes over time. So for general home or office light they can be efficient sources of light
Of course the use of CFLs should not be mandated by law, nor should the incandescents be outlawed: GE is actually working on an energy efficient Incandescent at this very moment.
Alternative Lighting Technologies
High Intensity Discharge (HID): This type of light produces light in a more efficient manner than any other technology out there at the moment. Depending on the gas/metal particles suspended in the lamp the lumen output ranges from 50 -> 150 lumen per watt. Those orange street and parking lot lights you see are High Pressure Sodium by and large with some in tunnels being Low Pressure Sodium. Wikipedia has a good entry about this for more information linked here. Metal Halide (linked here) produces a much whiter cleaner light and is used in many parking lots; especially car dealerships or areas where security cameras operate because they render colors so much better.
HID technology is efficient, but they last at most 24,000 hours of life (more than Fluorescent or Incandescent), but still less than LED technology and they also can have mercury vapor in them. In addition if the outer covering is punctured in HID spot lamps (useful in track lighting) the extreme amount of UV radiation that it produces will no longer be blocked and a person can receive a sunburn within two minutes of sustained exposure if they are within two feet of the lamp, and eye damage may also occur, so like anything care must be used when handling.
I am testing out a Philips HID spot as I write this, and for 25 watts it puts out tons of light (1220 lumen to be exact = 3x 100 watt incandescent). This HID however will also burn much hotter than a halogen lamp and one should not touch it after 10 minutes or more of running without gloves or some kind of protection from the heat. The estimated life of this lamp is 10,500 hours which is equal to or better than a CFL, and more efficient in lumen/watt. The downside is that it does dump substantially more heat in to the surroundings, and in the summer may result in a building's HVAC working harder to compensate. HID are on/off and cannot be used on dimmers or 3-way switches at the moment. Those blue car headlights that you see glaring at you in the mirror are HID and the blue color comes from being doped with Xenon gas that acts as a catalyst to speed up the start time on headlamps, since you can't always afford to wait 2 minutes for them to come to full power. Information on HID automotive lamps I have linked to here.
As for Halogen Lamps they also have great amounts of punch/throw, but are still less efficient than HID and do not last as long as HID. How Stuff Works has a great summary of Halogens linked here. They are commonly used as spotlights and are relatively cheap per bulb compared to HID and have more throw than CFL equivalents so they can do the same job from a higher ceiling. Halogens are also currently the typical headlamp for cars today, although HID is slowly replacing them as the technology filters down from the luxury models.
At Lightfair International I had the ability to see the products for LEDs that are in the pipe for the next year or so. By and large I was not impressed at all with the Chinese manufacturers that were present. Most of their products concentrated on the current market for LEDs, which is accent and decorative lighting using the 1/10Watt LEDs. The two current best manufacturers of LEDs are Cree and Philips LumiLEDs. Neither company however is actually marketing fixtures for the LEDs to the general public. However, other companies have packaged their LEDs and there is real progress. LEDs now are hitting the 80 Lumen/watt threshold, which makes them useful in general lighting. Basically this would if you could package 25 of these LEDs from Cree in to the same sized PAR30 (3 inch lens) spot as is the HID I am testing you would get 800 more lumen.
LEDs are here to stay and they will only get better. LEDs have many benefits over typical lighting systems, but also several drawbacks.
Color can either be from phosphor or LEDs controlled can mix RGB and with a computer system create a unique lighting control system commonly used in night club environs.
No UV radiation
Vibration and concussion resistant - will not shatter easily
Low Power - Good for automotive running lights especially on industrial and commercial trucks to reduce system load.
Low throw (when compared to HID and Halogen)
Lumen/watt while better than incandescent are inferior to some HID (for now).
They are still in early adopter phase of the product development life cycle. LEDs come in arrays - if one goes out you cannot just screw in a replacement - that are hardwired
LEDs work by passing electricity through a semi-conducting compound often composed of rare earth elements (heavy metals) like a compound of Aluminum-Gallium-Arsenide (yes there is an arsenic compound in them) in order to get them to emit light. To get white light there are two ways to do this; the popular...cheap and sloppy way, OR the more expensive, complicated and alternative way.
1) LED emits light on to the interior of its casing which is coated with a phosphor (like fluorescent) and that emits the white light. Sometimes if the coating is sloppy this can result in a greenish halo at the fringes and if one is displaying art or there are many white surfaces...these kind can be bad to use.
2) LEDs in a mixture of RGB like your conventional cathode ray tube TV's and LCD/CRT monitors mix the colors so that you can get a white light...in varying tones depending on the proportions and the mixing. With the right ballast/driver they can be used on smart dimmers and also controlled by a DMX computer system for even more flexibility. On the subject of dimmable LEDs when there is color mixing...the problems occur when you get below 50% power, and the wavelengths of the light begin to matter and it can turn greenish in tone. Work will of course be done to fix this or better dimmers for mixing, but right now options are limited.
Either way, you still get a green halo effect at the moment when you go for white light.
General Lighting via LEDs is just coming online this year in earnest and will become normalized within two years or so and you will see home depot carrying a good number of LED lighting options for the home. I know who the manufacturer will be by and large as they already do a selection of home depot's home fluorescent lighting.
Good uses for LED lighting include:
Jewelry Cases - any case lighting actually
Low Bay recessed lighting
Under Counter lights
accent and decorative
Underwater (clean and clear like a pool) and Ground Lighting
replacement for low voltage halogen track lighting
Bad Uses for LED include:
Highbay (over 16feet)
Car Dealership Parking Lots
Any situation requiring a high power light that has a lot of punch (HID and Halogen are better)
General Home Lighting - will get better in a year or so
(For good non-biased LED research check out RPI's Lighting Lab )
The bottom line is that any lighting technology has its uses depending on the application. CFL's are currently a cost and energy effective alternative to incandescent for the home and business owner...mercury being a relative non-concern unless one is compelled to call the EPA/DEP whenever there is a spill of SOME kind of chemical. when I tell fellow contractors about the toxic levels of mercury they just laugh in disbelief, but then again they are all mad hatters like me (joking).
HID style lighting is reliable in a wide variety of temperature ranges and functions much better than fluorescent in harsh environments like the Antarctic and under ocean water than fluorescent and provides better light. LED is currently useful in a wide variety of area, but mostly where one does not need a great deal of light. This will change and is changing rapidly, but even now HID flashlights use LEDs for the low power setting to preserve battery life. LEDs on vehicles may make good signal and running lights but as far as headlamps go they are not as effective has Halogen or HID technologies (yet).
Technological progress continues, driven by market forces, not mandates.