Through a process known as thermionic conversion, heat energy -- such as light from the sun or heat from burned fossil fuels -- can be converted into electricity with very high efficiency.
Because of its promise, researchers have been trying for more than half a century to develop a practical thermionic generator, with little luck. That luck may soon change, thanks to a new design -- dubbed a thermoelectronic generator -- described in AIP Publishing's Journal of Renewable and Sustainable Energy (JRSE).
Thermionic generators use the temperature difference between a hot and a cold metallic plate to create electricity. "Electrons are evaporated or kicked out by light from the hot plate, then driven to the cold plate, where they condense," explained experimental solid-state physicist Jochen Mannhart of the Max Planck Institute for Solid State Research in Stuttgart, Germany, the lead author of the JRSE paper. The resulting charge difference between the two plates yields a voltage that, in turn, drives an electric current, "without moving mechanical parts," he said.
Previous models of thermionic generators have proven ineffectual because of what is known as the "space-charge problem," in which the negative charges of the cloud of electrons leaving the hot plate repel other electrons from leaving it too, effectively killing the current. Mannhart, along with his former students Stefan Meir and Cyril Stephanos, and colleague Theodore Geballe of Stanford University, circumvented this problem using an electric field to pull the charge cloud away from the hot plate, which allowed electrons to fly to the cold plate.
"Practical thermionic generators have reached efficiencies of about 10 percent. The theoretical predictions for our thermoelectronic generators reach about 40 percent, although this is theory only," noted Mannhart. "We would be much surprised if there was a commercial application in the marketplace within the next five years, but if companies that are hungry for power recognize the potential of the generators, the development might be faster."
The article, "Highly-Efficient Thermoelectronic Conversion of Solar Energy and Heat into Electric Power" by S. Meir, C. Stephanos, T.H. Geballe, and J. Mannhart appears in the Journal of Renewable and Sustainable Energy. See: http://dx.doi.org/10.1063/1.4817730
Authors on this study are affiliated with Augsburg University in Germany; the Max Planck Institute for Solid State Research in Stuttgart, Germany; and Stanford University.ABOUT THE JOURNAL
Jason Socrates Bardi | EurekAlert!
Linear potentiometer LRW2/3 - Maximum precision with many measuring points
17.05.2017 | WayCon Positionsmesstechnik GmbH
First flat lens for immersion microscope provides alternative to centuries-old technique
17.05.2017 | Harvard John A. Paulson School of Engineering and Applied Sciences
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.
In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...
Dental plaque and the viscous brown slime in drainpipes are two familiar examples of bacterial biofilms. Removing such bacterial depositions from surfaces is...
For the first time, scientists have succeeded in studying the strength of hydrogen bonds in a single molecule using an atomic force microscope. Researchers from the University of Basel’s Swiss Nanoscience Institute network have reported the results in the journal Science Advances.
Hydrogen is the most common element in the universe and is an integral part of almost all organic compounds. Molecules and sections of macromolecules are...
22.05.2017 | Event News
17.05.2017 | Event News
16.05.2017 | Event News
22.05.2017 | Materials Sciences
22.05.2017 | Life Sciences
22.05.2017 | Physics and Astronomy