University of Minnesota Sign with flowers

Professor Richard James Receives TechConnect Innovation Award

Distinguished McKnight University Professor Richard James, Department of Aerospace Engineering & Mechanics, and Professor Bharat Jalan, Department of Chemical Engineering & Materials Science, have earned the TechConnect Innovation Award (2020). The professors led a research team that developed a new concept for direct conversion of heat to electricity, using ferroelectric oxide crystals. Former AEM Postdoctoral Fellow, Ashley Bucsek, also contributed importantly to this research.

The technology is designed for what Jalan and James call the “small temperature difference regime”.  This is the range, 10 - 400 F, for which there are ubiquitous natural and waste heat sources on earth. As James explains, “Whenever there is a temperature difference, there is the potential to convert heat flowing between the two temperatures into electricity. Currently, there is no reasonable method for this regime.”

The technology relies on the use of ferroelectric crystals that undergo highly reversible phase transformations from a paraelectric to a strongly ferroelectric phase upon cooling. As the crystal is cooled through the phase transformation, it releases (latent) heat, transforms to the ferroelectric phase, and develops a strong polarization. If this crystal is the dielectric of a capacitor connected in parallel to a reference capacitor, it will draw charge from the reference capacitor. Possible waste-heat sources include the industrial sector, data centers, power plants, computers, and hand-held electronic devices. James adds, “With suitable ferroelectric crystals the temperatures need not be above room temperature: the temperature difference between the water below the ice and the air in Minnesota during 3 months of winter is an enormous unexploited source of energy.”