28 March 2012
Scientists at the US Department of Energy’s National Renewable Energy Laboratory (NREL) and New Energy Technologies, Inc., a developer of next generation alternative and renewable energy technologies, have collaboratively created a virtually ‘invisible’ conductive wiring system to collect and transport electricity on commercial windows and structural glass, namely the company’s SolarWindow.
The technology is based on creatively layering and arranging unique, ultra-small see-through solar cells interconnected by an ‘invisible’ grid-like wiring system onto a glass window. It can generate electricity from sunlight, artificial light and low light. “The system helps mitigate electrical ‘road-blocks,’ which restrict the flow of electrons with regions of high resistance, by creating a kind of low-resistance ‘highway’ for electron transport,“ says John Conklin, president and CEO of New Energy Technologies, Inc. What’s more, a fully optimized conductive system will be able to prevent resistive losses and improve reliability by providing a stable network of connections among each of the interconnected solar cells on the see-through glass.
The ability to transport electricity on glass windows while remaining see-through could represent a significant advancement for building-integrated photovoltaics—or BIPV—on a large commercial scale. According to the company’s information, their conductive grid is virtually invisible when viewing objects through the electricity-generating glass. The invisible wiring system allows for more efficient collection and transport of electrons, both important for improving circuit current and overall efficiency.
New Energy is currently working on optimizing the visible light transmission—or VLT—of SolarWindow. The goal is to mimic the aesthetic look of popular clear to light window tints and films, which typically allow 40 - 80% of the visible light through the windows. However, SolarWindow prototypes are not yet installed in the field for performance testing. The team’s current priorities include “the development of additional patent protection, improved manufacturability, increased power production, advanced power output modeling and attracting management-level talent able to help advance our breakthrough technology from the research-bench to commercial market,” Conklin says.
Because New Energy’s electricity-generating coatings and SolarWindow are subject to patent filings, the company is not disclosing the structure or names of the polymer’s used other than that the “electricity-generating liquid coatings can be sprayed onto glass or applied using other inexpensive methods without high-temperature or pressure” and that “the technology is related to Organic Photovoltaic (OPV) Cell technology, according to Conklin.
New Energy reports that at a recent demonstration event at NREL, SolarWindow technology outperformed conventional commercial solar and thin-films by as much as 10-fold under low-intensity irradiance. Conklin says, “These data were obtained from Laboratory performance measurements for prototypes to evaluate low light conditions, and electrical voltage and current performance.” The technology is at the early development stages, and although Conklin wasn’t willing to speculate on electrical power information yet, he did say, “Common opaque solar cells are being mass produced with over 20% efficiencies, with 3-11% common on many gadgets. Efficiencies of any new solar tech would be expected to increase over time.”
Written by Sandra Henderson, Research Editor, Solar Novus Today
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