The pressure to conserve

LAFAYETTE — For energy companies supplying electricity to cities across the nation, small savings in fuel use during the energy production process can reap big rewards. Better fuel efficiency at the power plant means less environmental impact, fewer emissions and cost savings for both the company and the consumer. Even a fraction of a percent in fuel savings can spell measurable differences in power generation for a metropolitan-sized customer base.

Sometimes big breakthroughs in fuel efficiency come in small packages. Lafayette-based Sporian Microsystems Inc. develops pressure sensors used to increase fuel efficiency for use in turbine engines, a small-business innovation that could pay big in “green.”

Energy-generation companies are likely to be the first adopters of Sporian’s sensors, said Mike Usrey, vice president of Sporian Microsystems. Jet engines are another likely market, he added, because of their similarity to gas turbines. A new jet engine design uses a Sporian sensor. The approval process for jet engine parts is longer, though, because engine failure while in flight causes obvious risks, Usrey said. He hopes to see power turbine demonstration as early as 2014.

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“There are lots of pressure sensors in the world,” Usrey said. “What makes this one unique is it’s made from a polymer derived from ceramic so it can withstand very high temperatures and has very, very low corrosion.”

Current sensors often can’t withstand the high temperatures generated within a combustion turbine. Sporian’s sensors, sometimes called microelectromechanical systems or MEMS, can.

“Conventional sensors that are based on conventional electronics, such as silicon, are only capable of operating up to 200 degrees Celsius,” said Kevin Harsh, senior scientist and principal investigator for the high-temperature sensors at Sporian. Gas turbine engine temperatures exceed 1,000 degrees Celsius, or nearly 2,000 degrees Fahrenheit.

“At those temperatures silicon would burn up very quickly,” Harsh said. The leaner the engine burns, the better its fuel efficiency. If the engine burns too lean, though, it will stall.

Turbine engines need two things for an optimal lean burn.

“What you need is a really fast fuel valve that can increase and decrease the amount of fuel many times a second and a pressure sensor so the sensor can tell the fuel injector what to do,” Usrey said.

Conventional pressure sensors use a “static” measurement system. The sensor, placed outside the combustion area, collects gases, lets them cool, then adjusts fuel burn based on projections of what temperatures were moments earlier. It’s a slow method and not as accurate as real-time readings, Usrey said. Sporian sensors have been tested successfully at temperatures reaching 1,400 degrees Celsius, and testing is under way at higher temperatures.

“It sits in there at the hottest part and at the same temperature as everything else,” and delivering real-time data, Harsh said.

Harvey Niska, turbine engine test technology manager for Phoenix-based Honeywell Aerospace, facilitates the acceptance and adoption of technologies that enhance engine performance, thereby reducing cost and emissions. He gives Sporian’s sensor systems a thumbs-up.

“If you can operate your engine closer to the surge stall line,” Niska said, “it will allow for better engine performance and lower fuel consumption.”

Sporian began in 2000 when a group of engineering students from the University of Colorado received a grant from the National Science Foundation. Sporian’s eight employees do the research, design and manufacturing at its operations in Lafayette. The initial grant funded Sporian’s development of an effective three-dimensional MEMS manufacturing system. Since then Sporian has received funding from the U.S. Department of Energy, the National Institutes of Health and the U.S. Air Force, among others.

In March, Sporian received two Small Business Innovation Research grants from the Department of Energy, according to a press release from Sen. Michael Bennet’s office. Totaling $300,000, the grants will fund high-temperature sensor projects for possible use in nuclear power systems and fossil fuel energy generation systems. Such grants spur real change, said Niska.

“Kudos to the government agencies that fund these projects,” he said, “because otherwise these projects would never get the momentum they need to reach maturity.”

Niska is chairman of the Propulsion Instrumentation Working Group, a consortium of U.S. gas turbine manufacturers cooperatively working to advance turbine-engine technology.

Sporian has working relationships with all major U.S. power-turbine companies. Some have committed to cost-sharing for upcoming high-temperature sensor efforts, Usrey said.

Another advantage of Sporian’s ceramic sensors is their ability to withstand highly corrosive environments. This allows for use in concentrated-solar systems, which use mirrors to concentrate the sun’s rays and superheat a liquid. The produced steam can be used for power generation. Sometimes the liquid is a highly corrosive molten salt. Sporian’s sensors can tolerate both the heat and corrosion.