University of California, Berkeley researchers have developed a new thin-film system that harvests waste heat from high-speed electronics and turns it into energy.
According to the researchers, nearly 70 percent of the energy produced in the U.S. each year is wasted as heat. Much of that heat is less than 100 degrees Celsius and emanates from things like computers, cars or large industrial processes.
The Berkeley team contends that the new film can be applied to sources of waste heat like those mentioned above to produce energy at levels unprecedented for this kind of technology.
The thin-film system uses a process called ‘Pyroelectric Energy Conversion’ which is well suited for tapping into waste-heat energy supplies below 100 degrees Celsius, called low-quality waste heat.
Pyroelectric energy conversion, like many systems that turn heat into energy, works best using thermodynamic cycles, kind of like how a car engine works.
However, unlike the engine in a car, pyroelectric energy conversion can be realized entirely in the solid state with no moving parts as it turns waste heat into electricity.
The new results suggest that this nanoscopic thin-film technology might be particularly attractive for installing on and harvesting waste heat from high-speed electronics but could have a large scope of applications.
For fluctuating heat sources, the study reports that the thin film can turn waste heat into useable energy with higher energy density, power density and efficiency levels than other forms of pyroelectric energy conversion.
“We know we need new energy sources, but we also need to do better at utilizing the energy we already have,” said senior author Lane Martin, associate professor of materials science and engineering. “These thin films can help us squeeze more energy than we do today out of every source of energy.”
Martin’s research team synthesized thin-film versions of materials just 50-100 nanometers thick and then, together with the group of associate professor Chris Dames, fabricated and tested the pyroelectric-device structures based on these films.
The researchers hope to better optimize the thin-film materials to specific waste heat streams and temperatures in the near future.
Image and content: Shishir Pandya/University of California, Berkeley