It isn’t surprising that New York’s electrical grid malfunctioned during the big blackout of 2003, says one Rensselaer Polytechnic Institute professor. It’s not that the grid is antiquated; it’s that our demand for energy is insatiable.



While proponents of conservation seek ways to get people to use less energy, Anna Dyson, who teaches architecture at Rensselaer, has another idea. She is leading a team of researchers who are trying to prevent future power failures by making energy-sucking office buildings ultra-efficient at peak hours. They plan to combine a series of highly efficient, low-cost technologies into a single sustainable device that would be almost transparent to those using its energy.

To use a highly nontechnical term, call the devices solar window shades.



Imagine sitting at your office desk, looking through floor-to-ceiling windows. You look past dozens of tiny, translucent, 1-centimeter silicon squares suspended about every square foot or so between dual windowpanes. The little squares shift like automated, almost invisible Venetian blinds. The miniature squares follow the sun’s rays, so they don’t impede the view in any direction.



The entire module — a clear plastic pane between two glass panes — functions like a translucent sundial, letting you tell time with its shadows.



The glare that once bounced off your computer monitor no longer exists. And the sun’s intense heat, which once led to window-shade tug-of-wars with co-workers longing for a little natural light, no longer beats down on you. You comfortably tap at your keyboard under natural, abundant, ambient light.



But there’s a lot more going on than meets the eye. These photovoltaic window shades quietly capture the sun’s rays of heat and light, focusing them into the small silicon squares, also called solar chips. The chips convert the light energy into electrical power and feed it into the building’s electrical system; the energy goes into the heating and cooling systems.



While Dyson won’t comment on actual costs and efficiency rates until the research is published this fall, she did reveal that Bernie Sater at Photovolt, Rensselaer’s manufacturing and design partner, has developed a new manufacturing process that “gets the cost down far enough that you can use it.”



Dyson said a single solar cell will cost about 25 cents. The cells are situated about a square foot apart and will have a “way more than 50 percent” energy-conversion rate, she added. Typical solar panels have a conversion rate of less than 20 percent.



Ultimately, Dyson is confident her team’s solar cells can reach nearly four times the power production of existing solar products. But, to compare energy alternatives accurately, it’s necessary to calculate the cost per watt or a similar ratio. Dyson, however, said it is too early to make that projection.



Rensselaer’s vertical multijunction solar-cell project, which began in 2000, is still in the prototype stage. It’s busily capturing energy — and research data — on the roof of the university’s science building.



The university is seeking both patents and a government contract to move to the next prototyping step. Dyson hopes to see the technology in use in three to five years.
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