Recycling, solar energy updates

Wanted: Larger recycling bins

Researchers pioneer a new recycling process that is turning old cars into "green" cars.

Materials recovered from junked automobiles are being recycled and used to manufacture new parts for the interiors of vehicles using a new process, froth flotation, developed by Argonne National Laboratory (operated by the University of Chicago for the U.S. Department of Energy). Containing at least 25 percent recycled content, these "green" cars use recycled polyurethane foam and plastics from obsolete vehicles. In cooperation with the Lear Corp., a leading global supplier to the automotive interior market, "green cars"—integrated with Lear's vehicle interiors—contain more than 40 percent recycled content.

The froth flotation process provides a method for separating high-value plastics of equivalent density from mixed plastics. About 75 percent of a junked automobile—the metal—is recycled through shredding. The froth flotation process allows two or more equivalent density plastics to be separated with high purity from the remaining material.

Manipulation of the froth solution's chemistry makes it possible to attach small bubbles to the surface of one material and not another. By affecting the density of the materials, one plastic floats while the others sink. The recovered plastics are of commercial quality and cost competitive with new plastics. Recycling the leftover materials from automobile shredders can eliminate as much as 60 percent of auto disposal landfill waste.
For more information, please contact Catherine Foster (630-252-5580 or at Argonne.

Prospects brighten for solar energy

The U.S. Department of Energy's Oak Ridge National Laboratory (ORNL) is developing a system that could boost conventional solar technology capabilities three-fold.

The "full-spectrum solar energy system" harnesses the clean and abundant energy found in sunlight and uses that energy more efficiently than traditional solar systems. Conventional technology uses solar energy for a single purpose, such as generating power.

"Instead of inefficiently converting the visible light found in sunlight into electricity only to reconvert a sizeable portion back into interior light," said Jeff Muhs, a researcher in ORNL's Engineering Technology Division, "the new technology will collect and distribute the light directly."

Interior lighting is the single largest use of electrical power in commercial buildings, accounting for more than a third of all the electricity consumed comercially in the United States.

"By using the visibe portion of the light spectrum, we can reduce the amount of electricity we consume for lighting commercial buildings. We can use the other portions of the spectrum to generate electricity," said Muhs.

Using novel roof-mounted, two-axis tracking concentrators that separate the visible and infared portions of the sun's rays, the new system uses large-diameter optical fibers to distribute visible light to the interiors of buildings. Infared portions of the solar spectrum are converted into electricity. Models developed at ORNL and independently verified suggest that the overall efficiency and affordability of solar energy can be improved by as much as threefold in commercial buildings when compared to conventional solar technologies.
For more information contact Ron Walli (423-576-0226) at ORNL.

This article originally appeared in the 02/01/2000 issue of Environmental Protection.

About the Author

Hu Fleming, PhD, is vice president of the Water Purification Solutions Group, Severn Trent Services Inc., Ft. Washington, Penn.

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