Sandia National Labs develops chip to turn heat into power

Published on July 11, 2018 by Dave Kovaleski

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Researchers from Sandia National Laboratories have developed technology that can turn heat into electrical power.

Through their study, which was published in Physical Review Applied, the Sandia research team developed a tiny silicon-based device includes a rectangular chip with etched stripes next to a plasma sphere, which they call a rectifying antenna, or rectenna. It is about 1/8 inch by 1/8 inch, which is half as thick as a dime. The device can catch and convert waste heat into electrical power.

“We have developed a new method for essentially recovering energy from waste heat. Car engines produce a lot of heat, and that heat is just waste, right?” Paul Davids, a physicist and the principal investigator for the study, said. “So imagine if you could convert that engine heat into electrical power for a hybrid car. This is the first step in that direction, but much more work needs to be done.”

The researchers specifically focused on the scalability of common materials and processes, Joshua Shank, an electrical engineer and the paper’s first author, said.

One of the biggest challenges was inserting small amounts of other elements into the silicon, which was necessary to reflect infrared light like a metal.

“Typically you don’t dope silicon to death; you don’t try to turn it into a metal because you have metals for that. In this case, we needed it doped as much as possible without wrecking the material,” Rob Jarecki, the fabrication engineer who led process development, said.

From a specialized heat lamp at 840 degrees, the device produces 8 nanowatts of power per square centimeter.

“We’ve been whittling away at the problem, and now we’re beginning to get to the point where we’re seeing relatively large gains in power conversion, and I think that there’s a path forward as an alternative to thermoelectrics. It feels good to get to this point. It would be great if we could scale it up and change the world,” Davids said.