Featured Research

from universities, journals, and other organizations

Nano-breakthrough: Dramatic Increase In Thermoelectric Efficiency Heralds New Era In Heating, Cooling And Power Generation

Date:
March 21, 2008
Source:
Boston College
Summary:
Researchers 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, detailed in Science, involves building tiny alloy nanostructures that can serve as micro-coolers and power generators.

A cross-section of nano-crystalline bismuth antimony telluride grains, as viewed through transmission electron microscope. Colors highlight the features of each grain of the semiconductor alloy in bulk form. A team of researchers from Boston College and MIT produced a major increase in thermoelectric efficiency after using nanotechnology to structure the material, which is commonly used in industry and research.
Credit: Boston College, MIT and GMZ Inc.

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 in 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 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.

This research will be published online in Science Express on March 20, 2008. The research was supported by the Department of Energy and by the National Science Foundation.


Story Source:

The above story is based on materials provided by Boston College. Note: Materials may be edited for content and length.


Cite This Page:

Boston College. "Nano-breakthrough: Dramatic Increase In Thermoelectric Efficiency Heralds New Era In Heating, Cooling And Power Generation." ScienceDaily. ScienceDaily, 21 March 2008. <www.sciencedaily.com/releases/2008/03/080320150027.htm>.
Boston College. (2008, March 21). Nano-breakthrough: Dramatic Increase In Thermoelectric Efficiency Heralds New Era In Heating, Cooling And Power Generation. ScienceDaily. Retrieved July 24, 2014 from www.sciencedaily.com/releases/2008/03/080320150027.htm
Boston College. "Nano-breakthrough: Dramatic Increase In Thermoelectric Efficiency Heralds New Era In Heating, Cooling And Power Generation." ScienceDaily. www.sciencedaily.com/releases/2008/03/080320150027.htm (accessed July 24, 2014).

Share This




More Matter & Energy News

Thursday, July 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Robot Parking Valet Creates Stress-Free Travel

Robot Parking Valet Creates Stress-Free Travel

AP (July 23, 2014) — 'Ray' the robotic parking valet at Dusseldorf Airport in Germany lets travelers to avoid the hassle of finding a parking spot before heading to the check-in desk. (July 23) Video provided by AP
Powered by NewsLook.com
Boeing Ups Outlook on 52% Profit Jump

Boeing Ups Outlook on 52% Profit Jump

Reuters - Business Video Online (July 23, 2014) — Commercial aircraft deliveries rose seven percent at Boeing, prompting the aerospace company to boost full-year profit guidance- though quarterly revenues missed analyst estimates. Bobbi Rebell reports. Video provided by Reuters
Powered by NewsLook.com
Europe's Car Market on the Rebound?

Europe's Car Market on the Rebound?

Reuters - Business Video Online (July 23, 2014) — Daimler kicks off a round of second-quarter earnings results from Europe's top carmakers with a healthy set of numbers - prompting hopes that stronger sales in Europe will counter weakness in emerging markets. Hayley Platt reports. Video provided by Reuters
Powered by NewsLook.com
9/11 Commission Members Warn of Terror "fatigue" Among American Public

9/11 Commission Members Warn of Terror "fatigue" Among American Public

Reuters - US Online Video (July 22, 2014) — Ten years after releasing its initial report, members of the 9/11 Commission warn of the "waning sense of urgency" in combating terrorists attacks. Mana Rabiee reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins