MIT researchers and their collaborators have come up with an unusual, high performance and possibly less expensive way of turning the sun’s heat into electricity.
Their system, described in a paper published online in the journal Nature Materials on May 1, produces power with an efficiency roughly eight times higher than ever previously reported for a solar thermoelectric device — one that produces electricity from solar heat. It does so by generating and harnessing a temperature difference of about 200 degrees Celsius between the interior of the device and the ambient air.
The concept “is very radical,” says Gang Chen, MIT’s Carl Richard Soderberg Professor in Power Engineering and director of the Pappalardo Micro and Nano Engineering Laboratories, who co-authored the new paper with MIT doctoral student Daniel Kraemer and collaborators from Boston College and GMZ Energy. The work is funded by the Solid-State Solar-Thermal Energy Conversion Center, an Energy Frontier Research Center at the U.S. Department of Energy.
While solar thermal electricity systems aren’t a new idea, they typically involve vast arrays of movable mirrors that track the sun and focus its rays on a small area. The new approach uses flat, stationary panels similar to traditional solar panels, eliminating the need for tracking systems.
Like the silicon photovoltaic cells that produce electricity when struck by sunlight, Chen’s system is a solid-state device with no moving parts. A thermoelectric generator, placed inside a vacuum chamber made of glass, is covered with a black plate of copper that absorbs sunlight but does not re-radiate it as heat. The other side of the generator is in contact with ambient temperatures. Placed in the sun, the entire unit heats up quickly, even without facing the sun directly.
The device requires much less material than conventional photovoltaic panels, and could therefore be much less expensive to produce. It can also be integrated into solar hot water systems, allowing the expenses of the structure and installation to serve two functions at once. Such solar water heaters are rarely seen in the United States, but are already a highly successful mass-market product in China and Europe, where they provide households with hot water and in some cases space heating as well.
The materials used to build such solar thermoelectric generators, made through a nanostructured process, were developed jointly a few years ago in Chen’s lab at MIT and in co-author Zhifeng Ren’s lab at Boston College. Their teams have continued to work on improving these materials and integrating them into complete systems.
Chen points out that the U.S. Department of Energy has programs to develop thermoelectric systems, mostly geared toward harnessing waste heat from car and truck engines. He says that solar applications for such devices also can “have an important role to play” in reducing carbon emissions. “Hopefully we can prove that,” he adds.
Li Shi, associate professor of mechanical engineering at the University of Texas at Austin, says this approach to solar power is “very novel, simple, and easy for low-cost implementation.” The efficiency level they have demonstrated so far, at 4.6 percent, is “already quite impressive,” he says.
“With the use of other or new thermoelectric materials that can operate at a higher temperature,” Shi adds, “the efficiency may be improved further to be competitive with that for state-of-the-art amorphous silicon solar cells. This can potentially provide a different approach to realizing the $1-per-watt goal for solar-electricity conversion.”
The new system wouldn’t be a substitute for solar photovoltaics, Chen says, but offers “another way” of tapping into the enormous amount of solar energy that bathes the Earth every day. And because it can be piggybacked onto the existing solar hot-water industry, the thermoelectric device could be a relatively inexpensive addition, with “no subsidies required,” Chen suggests. “It can be a game-changing thing,” he says.
Caroline McCall | EurekAlert!
Did you know that the wrapping of Easter eggs benefits from specialty light sources?
13.04.2017 | Heraeus Noblelight GmbH
To e-, or not to e-, the question for the exotic 'Si-III' phase of silicon
05.04.2017 | Carnegie Institution for Science
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
25.04.2017 | Physics and Astronomy
25.04.2017 | Materials Sciences
25.04.2017 | Life Sciences