Rensselaer Magazine December 2008 - “Lighting the Way” Page 2

“Initially the industry fought us,” says Rea, recalling LRC’s battle to establish the testing center. “Then it turned out, after we began publishing results, that some of the companies that hated us most instead loved us most, because we were telling the truth about their products. Now they point to our testing program to say, ‘See? Ours is real.’ ”

LRC often finds itself de-mystifying claims about light. For example, there are claims that “full-spectrum lighting” enhances mood and health by reproducing the effects of daylight indoors. The LRC took a dispassionate view of these claims describing both the benefits and the costs associated with “full-spectrum lighting.” The first thing they did, however, was to define “full spectrum” so that everyone was on the same page.

Some full-spectrum lights yield better results than others and at widely varying costs. But, as LRC has reported, the claimed superior physiological benefits of full-spectrum lighting remain unproven. Thus, perceived benefits may stem from the way these products are promoted, since “cleverly marketed full-spectrum light sources may provide beneficial effects to some people susceptible to that marketing.” In this case, as in many others, LRC researchers do not just grade products, they evaluate the underlying concept.

Power Surge

LRC takes light testing a step further with the development of new tools of measurement. To quantify how humans respond to light, for instance, researchers created the Daysimeter™, a small measuring rod that faces forward while clipped to the ear of research subjects. “Being able to measure light is essential, or otherwise we can’t talk seriously about it,” says Mariana Figueiro, LRC assistant professor who studies the health effects of light. “We want to put more precision into statements about the impact of light on people.”

Another LRC research scientist, Jennifer Brons, has developed a standardized system of quantifying public light pollution, by measuring the glare in a cubic volume of space produced by, say, lights at shopping centers or high school football fields. This can allow local governments to use firm statistics when resolving light-use disputes. “We want to help people get away from just using rhetoric,” says Brons.

An LRC researcher “snaps” an LED panel into the electrical grid. The panels can be rearranged simply and rapidly to cater to changing room layouts or personal preference.

A promising LRC innovation, called “load-shedding ballast,” is a technology that lets commercial buildings cut light use at peak hours of electricity consumption. The center first developed it as a prototype in 2002, led by senior scientist Andrew Bierman, and it has since been commercialized by Osram Sylvania, which calls it the “PowerSHED.”

Essentially, the PowerSHED consists of a signaling device and a ballast that limits the flow of electricity through commercial lighting systems. It reduces peak electric energy consumption thus saving money, relieves stress on the power grid, especially in summer when energy consumption is high, and by saving energy it aids the environment. The energy savings, says Rea, are “the equivalent of putting a small power plant in the ceiling,” since 25 percent of national electric energy consumption is used for light.

Beyond constructing the technology, Bierman and other LRC researchers faced a tricky people problem: figuring out to what extent light can be dimmed before it affects workers. They made some surprising discoveries, including that light can be reduced by about 15 percent before many workers even notice a difference. However, the economics of buying and installing a ballast system are such that LRC researchers wanted to create light savings of around 30 percent.

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Rensselaer (ISSN 0898-1442) is published in Spring, Summer, Fall, and Winter by the Office of Strategic Communications and External Relations, Rensselaer Polytechnic Institute, Troy, NY 12180-3590. Opinions expressed in these pages do not necessarily reflect the views of the editors or the policies of the Institute. ©2008 Rensselaer Polytechnic Institute.