Okay, so maybe Damon Runyon was not thinking about a government-supported energy efficiency research project when he wrote, “the race is not always to the swift, nor the battle to the strong, but that’s how the smart money bets.” But if he was alive today, he might have been thinking of the Department of Energy’s Universal Smart Window project. DOE has just bet a cool $3 million that the project will deliver a low-cost, high-tech window coating that will dramatically cut the energy used in buildings.
A $3 Million Bet on Energy Efficient Smart Windows
Windows are a massive Achilles’s heel for buildings in terms of energy efficiency, despite some improvements over the years. That puts windows front and center in President Obama’s Better Buildings national energy efficiency initiative, in case you were wondering why the Department of Energy is so interested in windows all of a sudden.
So, here’s the deal. The Energy Department’s Advanced Research Projects Agency-Energy (ARPA-E) has awarded a grant of $3 million to researcher Delia Milliron, Deputy Director of the Molecular Foundry, to develop a new electrochromic window coating that adjusts to changes in weather and light conditions (the Molecular Foundry is a project under the auspices of Lawrence Berkeley Laboratory that promotes nanoscale research).
The coating serves as a self-regulating interface that prevents too much light and heat from getting into a building. Conversely, the coating admits more light and heat whenever that would enable the building to save energy.
We Built This!
Milliron’s project is a collaboration between the Berkeley lab and a startup called Heliotrope Technologies, which was spun off from the Molecular Foundry into the private sector.
Heliotrope was recently declared the winner of the 2012 NOVA Innovation competition for its work with self-regulating window coatings.
The new coating uses a small jolt of electricity to create variations in the degree a window will transmit visible light and near-infrared radiation, which produces heat. According to Berkeley Lab:
“In this way, the sun’s power can be harnessed to permit maximal light and heat to enter in cold weather, while preventing unwanted heating and glare on hot, sunny days. Ultimately, such dynamic windows would be integrated with an intelligent control system to maximize energy savings and make buildings more comfortable.”
The Berkeley team will work with Heliotrope and other researchers to refine the Universal Smart Window coating, which is actually a thin film of transparent nanocrystals embedded in a matrix.
So far, the team has used tin-doped indium oxide and aluminum-doped zinc oxide nanocrystals. The matrix could be a metal oxide that reacts to an electrical current, or it could be a passive electrolyte.
Smart Windows for Everybody
Electrochromic window coatings are not particularly new, but the ones in existence today are expensive and unable to respond to seasonal changes.
Those factors have limited their use. The Universal Smart Window project, in accordance with its name, is aimed at producing a low-cost coating that could be applied to just about any window, anywhere.
The folks at Berkeley and Heliotrope better work fast, though, if they want bragging rights to the first switchable window coating on the market. Dow Corning, for one, is hard at work on a similar coating based on liquid silicon crystals.
Meanwhile, this could all be just the tip of the iceberg in terms of squeezing extra juice out of windows. A company called New Energy Technologies has been working under a federal grant to develop a transparent coating that turns windows into solar power generators, and UCLA is working on a transparent solar cell that could be used in place of conventional windows.
Follow me on Twitter: @TinaMCasey
Tina Casey specializes in military and corporate sustainability, advanced technology, emerging materials, biofuels, and water and wastewater issues. Tina’s articles are reposted frequently on Reuters, Scientific American, and many other sites. You can also follow her on Twitter @TinaMCasey and Google+.