Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Boston College, MIT researchers achieve dramatic increase in thermoelectric efficiency

25.03.2008
Nanotech advance heralds new era in heating, cooling and power generation

Researchers at Boston College and MIT have used nanotechnology to achieve a major increase in thermoelectric efficiency, a milestone that paves the way for a new generation of products - from semiconductors and air conditioners to car exhaust systems and solar power technology - that run cleaner.

The team's low-cost approach, details of which are published today in the online version of the journal Science, involves building tiny alloy nanostructures that can serve as micro-coolers and power generators. The researchers said that in addition to being inexpensive, their method will likely result in practical, near-term enhancements to make products consume less energy or capture energy that would otherwise be wasted.

The findings represent a key milestone in the quest to harness the thermoelectric effect, which has both enticed and frustrated scientists since its discovery in the early 19th century. The effect refers to certain materials that can convert heat into electricity and vice versa. But there has been a hitch in trying to exploit the effect: most materials that conduct electricity also conduct heat, so their temperature equalizes quickly. In order to improve efficiency, scientists have sought materials that will conduct electricity but not similarly conduct heat.

Using nanotechnology, the researchers at BC and MIT produced a big increase in the thermoelectric efficiency of bismuth antimony telluride - a semiconductor alloy that has been commonly used in commercial devices since the 1950s - in bulk form. Specifically, the team realized a 40 percent increase in the alloy's figure of merit, a term scientists use to measure a material's relative performance.

The achievement marks the first such gain in a half-century using the cost-effective material that functions at room temperatures and up to 250 degrees Celsius. The success using the relatively inexpensive and environmentally friendly alloy in bulk form means the discovery can quickly be applied to a range of uses, leading to higher cooling and power generation efficiency.

“By using nanotechnology, we have found a way to improve an old material by breaking it up and then rebuilding it in a composite of nanostructures in bulk form,” said Boston College physicist Zhifeng Ren, one of the leaders of the project. “This method is low cost and can be scaled for mass production. This represents an exciting opportunity to improve the performance of thermoelectric materials in a cost-effective manner.”

“These thermoelectric materials are already used in many applications, but this better material can have a bigger impact,” said Gang Chen, the Warren and Towneley Rohsenow Professor of Mechanical Engineering at MIT and another leader of the project.

At its core, thermoelectricity is the “hot and cool” issue of physics. Heating one end of a wire, for example, causes electrons to move to the cooler end, producing an electric current. In reverse, applying a current to the same wire will carry heat away from a hot section to a cool section. Phonons, a quantum mode of vibration, play a key role because they are the primary means by which heat conduction takes place in insulating solids.

Bismuth antimony telluride is a material commonly used in thermoelectric products, and the researchers crushed it into a nanoscopic dust and then reconstituted it in bulk form, albeit with nanoscale constituents. The grains and irregularities of the reconstituted alloy dramatically slowed the passage of phonons through the material, radically transforming the thermoelectric performance by blocking heat flow while allowing the electrical flow.

In addition to Ren and six researchers at his BC lab, the international team involved MIT researchers, including Chen and Institute Professor Mildred S. Dresselhaus; research scientist Bed Poudel at GMZ Energy, Inc, a Newton, Mass.-based company formed by Ren, Chen, and CEO Mike Clary; as well as BC visiting Professor Junming Liu, a physicist from Nanjing University in China.

Thermoelectric materials have been used by NASA to generate power for far-away spacecraft. These materials have been used by specialty automobile seat makers to keep drivers cool during the summer. The auto industry has been experimenting with ways to use thermoelectric materials to convert waste heat from a car exhaust systems into electric current to help power vehicles.

The research was supported by the Department of Energy and by the National Science Foundation.

This paper will be published online by the journal Science, at the Science Express web site, on THURSDAY, March 20, 2008. See http:// www.sciencexpress.org, and also http://www.aaas.org.

Written by Ed Hayward, Boston College Office of Public Affairs

Elizabeth A. Thomson | MIT News Office
Further information:
http://www.mit.edu
http://web.mit.edu/newsoffice/www

More articles from Power and Electrical Engineering:

nachricht Hybrid storage with market potential: Battery production goes Industrie 4.0
01.03.2017 | Fraunhofer Institute for Applied Polymer Research IPA

nachricht WSU research advances energy savings for oil, gas industries
28.02.2017 | Washington State University

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

Im Focus: Safe glide at total engine failure with ELA-inside

On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded after a glide flight with an Airbus A320 in ditching on the Hudson River. All 155 people on board were saved.

On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded...

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

A better way to measure the stiffness of cancer cells

01.03.2017 | Health and Medicine

Exploring the mysteries of supercooled water

01.03.2017 | Physics and Astronomy

Research team of the HAW Hamburg reanimated ancestral microbe from the depth of the earth

01.03.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>