Researchers at the Massachusetts Institute of Technology have a higher efficiency solar thermoelectric device that coupled with a flat, stationary panel design eliminates the need for a tracking system thus reducing its
A solar thermoelectric device can produce electricity from generating and harnessing temperature differences. In the case of the M.I.T. discovery, they utilize a device that can generate power from a temperature difference of about 200 degrees Celsius between the interior of the device and ambient air.
Researchers Gang Chen, M.I.T.’s professor in power engineering, and Daniel Kraemer, an institute doctoral student developed the device prototype along with collaborators from Boston College and GMZ Energy.
They placed a thermoelectric generator inside a vacuum chamber made of glass. The generator is covered with a black plate of copper which effectively absorbs heat while not re-radiating it. Meanwhile, the other side of the generator has contact with ambient temperatures.
Because of the whole design, simply placing it under the sun can quickly heat it up without having it face the sun directly. The device is said to be able to produce power with efficiency roughly eight times higher than previously reported for other solar thermoelectric devices.
The typical solar thermal electricity systems utilizes a number of arrays of movable mirrors that track the sun, its rays are then focused onto a small area. However, the device developed by Mr. Chen and his team is a solid-state device with no moving parts.
Since the device does not have any moving parts, it requires much less material than conventional photovoltaic panels, which could therefore lead to cheaper production. In addition, the device could double as a water heater by integrating it into solar hot water systems.
Mr. Chen pointed out that the thermoelectric device could be a relatively inexpensive addition to the solar hot-water industry and that the device would not require any subsidies.
Through a nanostructured process, the materials used to create the solar thermoelectric generators were jointly developed a few years ago in Mr. Chen’s lab at M.I.T. and in a co-author’s lab at Boston College.
Currently, with an efficiency of 4.6, the team has been continuing their work to improve the materials needed and integrating them into complete systems.
“With the use of other or new thermoelectric materials that can operate at a higher temperature, the efficiency may be improved further to be competitive with that for state-of-the-art amorphous silicon solar cells,” an associate professor of mechanical engineering at the University of Texas at Austin, Li Shi explained.
“This can potentially provide a different approach to realizing the $1-per-watt goal for solar-electricity conversion,” the professor added.
Another institution looking at thermoelectric materials is the Department of Energy’s Oak Ridge National Laboratory. The lab believes that the material can be used in a new, energy-saving technology if it were only more efficient. In order to improve its efficiency, the researchers are seeking to understand the material in the atomic level.
