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  • LEDs, OLEDs for Sustainable, Energy-Efficient Lighting

Photonics Spectra
Jun 2011
Glass fiber optics, custom LEDs and organic LEDs are at the forefront of imaginative choices for affordable, sustainable, satisfactory, safe and energy-efficient lighting.

Gersil N. Kay, IESNA, Conservation Lighting International Ltd.

To expedite their research, scientists and engineers must use every resource possible. Good instruments are essential, of course, but so is the lighting for seeing the task at hand and getting the job done.

Contrary to popular opinion, lighting design is not a do-it-yourself job. As with brain surgery, it requires a professional: Between reading instructions and slicing, you could die of a misprint, to paraphrase Mark Twain. In the mercurial domain of lighting, so many variables exist that only those who are knowledgeable about its properties and performance can tame it. Special effects such as color, motion and dimming are possible with just push-button control, but the designer must be properly trained to execute this.


Color temperature makes a difference: Incandescent 2700 K color is seen in front, and metal halide 4100 K color is seen in back. Images courtesy of Gersil N. Kay, Conservation Lighting International Ltd.


The long history of the lighting field is complex and continues to evolve. The original “green” construction methods for providing effective lighting and ventilation have progressed from thousands of years of trial and error. A similar experimental approach to developing artificial illumination continues today as researchers worldwide develop lighting that is affordable, sustainable, satisfactory, safe and energy-efficient.

In the lighting field, one size or type does not fit all. Only if all the most energy-efficient lighting techniques best suited to the particular application are known can affordable, sustainable and sophisticated illumination be created within the guidelines of increasingly stringent energy conservation regulations.

Negotiating the lighting business also means having a thorough understanding of what you are purchasing. Obviously, manufacturers do everything possible to sell their wares. Sometimes, however, eagerness to sell goods creates advertising that is overly fanciful and neglects to mention key properties. This hinders the buyer’s ability to make the wisest decisions about which equipment and techniques to use. Truth in advertising would benefit everyone.

Another key to successful lighting design is abiding by the building codes and standards while still focusing on design and aesthetics. These codes and standards represent only the barest minimum of requirements. Design is not considered at all. Also related to codes and standards is the matter of recognizing the difference between older materials and methods – prior to 1940 – and those employed today. Failure to use imagination and common sense can waste money, effort and usable materials and can yield results that are disappointing: Envision destroying a beautiful marble staircase that has been safe for 125 years and replacing it with open slats that provide neither the beauty nor the privacy and protection of the original. Aesthetics and appropriateness also play a role in the lighting field.

For lighting designers in the US to catch up to those overseas, we must adopt methods that have long been used successfully; we are at least 10 years behind our foreign colleagues and eventually end up buying their inventions. The reasons for this situation include a lack of practical lighting education, terminal inertia in changing procedures, and the sometimes still-insufficient information available on compact fluorescent lightbulbs and LEDs, despite massive quantities of it (Both technologies are highly innovative but are not there yet).


A glass fiber optics projector containing a metal halide lamp, small fan and optics. The lightguides were designed to simply be inserted into the 30-mm boss of the projector, which arrives factory assembled, so there is no labor.


Three types of imaginative lighting are already in use overseas: glass fiber optics (GFO) for functional, as opposed to decorative, lighting; custom LEDs; and, soon, organic LEDs. Each product serves a different purpose and can be carefully combined with another or used separately. New developments appear almost daily. Here are some examples:

1. Functional GFO has been around the longest; the first patent for GFO was issued in 1882, but this method is still the most energy-efficient. Based on the principle of total internal reflection, GFO is not identical to the fiber optics used for communications; they are not interchangeable. Cool, reusable GFO is miniaturized, so it can be retrofitted into most existing lighting fixtures. It is the most sustainable because, with normal use, only a few lamps will need relamping as often as 6000 hours (about a year and a half). Substantial savings in installation, maintenance and operation lead to prompt payback on initial investment, plus continued savings thereafter for the long life of this completely different source/system.


Many custom and stock fittings can be manually screwed onto threaded metal ferrules for easy replacement and secure focus.


2. Custom LEDs can be retrofitted to existing fixtures/spaces or unique applications. They are made to dissipate the heat generated by the driver. Because of the size of the components needed to dissipate heat, current LEDs cannot be retrofitted easily into existing fixtures. Caveats: Additional air conditioning is always required. LEDs are vulnerable to moisture, temperature, voltage change and vibration. After 25,000 hours (five years), LED light levels could decrease to less than 70 percent of initial output, which may be less than is needed. Then the entire expensive system may have to be replaced. Individually replaced units may be very conspicuous next to older ones. The color white is still under development, and current versions can change color unexpectedly, defeating their purpose for research. LED light levels are not yet as high as conventional lamp light levels.


Lighting design can be crucial to safety: A glaring LED light near the bottom of a stair can cause an accident if the person descending is blinded by the bright light.


3. Organic LEDs are the latest development. They are manufactured in a simple printing process. This is different from original LEDs, which contain many components from different sources with varied quality (as do automobiles). Organic LEDs can be inserted into architectural surfaces, furniture, glass (to be translucent or transparent) and even into fabrics. The only drawback for wireless use is that lengthy operation requires a long-lasting lightweight battery.

New types of lighting careers have emerged, and each specialist can be instrumental in a variety of projects. One option is commissioning, as is done for heating, ventilation and air conditioning. Another approach is following a project from concept and design to installation, maintenance, operation and final disposal. A third is the building information model, in which a lighting design specialist traces the project from the very beginning and furnishes 3-D drawings of what was actually installed, and where. This is invaluable for future maintenance and repair. Indeed, scheduled maintenance might be replaced by predictable maintenance, where the manager could forecast which items are about to fail and could institute early steps to avoid costly shutdowns or loss of experiments.

Meet the author

Gersil N. Kay, IESNA, is president of Conservation Lighting International Ltd. in Philadelphia; e-mail: bciorg2@yahoo.com.


GLOSSARY
color
The attribute of visual experience that can be described as having quantitatively specifiable dimensions of hue, saturation, and brightness or lightness. The visual experience, not including aspects of extent (e.g., size, shape, texture, etc.) and duration (e.g., movement, flicker, etc.).
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