Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Material May Help Autos Turn Heat into Electricity

Abstract:
Researchers invented a new material that will make cars even more efficient, by converting heat wasted through engine exhaust into electricity. The material has twice the efficiency of anything currently on the market, and could also work in power generators and heat pumps.

Material May Help Autos Turn Heat into Electricity

Columbus, OH | Posted on July 24th, 2008

Researchers have invented a new material that will make cars even more efficient, by converting heat wasted through engine exhaust into electricity.

In the current issue of the journal Science, they describe a material with twice the efficiency of anything currently on the market.

The same technology could work in power generators and heat pumps, said project leader Joseph Heremans, Ohio Eminent Scholar in Nanotechnology at Ohio State University.

Scientists call such materials thermoelectric materials, and they rate the materials' efficiency based on how much heat they can convert into electricity at a given temperature.

Previously, the most efficient material used commercially in thermoelectric power generators was an alloy called sodium-doped lead telluride, which had a rating of 0.71. The new material, thallium-doped lead telluride, has a rating of 1.5 -- more than twice that of the previous leader.

What's more important to Heremans is that the new material is most effective between 450 and 950 degrees Fahrenheit -- a typical temperature range for power systems such as automobile engines.

Some experts argue that only about 25 percent of the energy produced by a typical gasoline engine is used to move a car or power its accessories, and nearly 60 percent is lost through waste heat -- much of which escapes in engine exhaust.

A thermoelectric (TE) device can capture some of that waste heat, Heremans said. It would also make a practical addition to an automobile, because it has no moving parts to wear out or break down.

"The material does all the work. It produces electrical power just like conventional heat engines -- steam engines, gas or diesel engines -- that are coupled to electrical generators, but it uses electrons as the working fluids instead of water or gases, and makes electricity directly."

"Thermoelectrics are also very small," he added. "I like to say that TE converters compare to other heat engines like the transistor compares to the vacuum tube."

The engineers took a unique strategy to design this new material.

To maximize the amount of electricity produced by a TE material, engineers would normally try to limit the amount of heat that can pass through it without being captured and converted to electricity. So the typical strategy for making a good thermoelectric material is to lower its thermal conductivity.

In Heremans' lab, he used to work to lower the thermal conductivity by building nanometer-sized structures such as nanowires into materials. A nanometer is one billionth of a meter.

Those nanostructured materials are not very stable, are very difficult to make in large quantities, and are difficult to connect with conventional electronic circuits and external heat sources.

For this new material, he and his colleagues took a different strategy: they left out the fancy nanostructures, and instead focused on how to convert the maximum amount of heat that was trapped in the material naturally.

To do this, they took advantage of some new ideas in quantum mechanics.

Heremans pointed to a 2006 paper published by other researchers in the journal Physical Review Letters, which suggested that elements such as thallium and tellurium could interact on a quantum-mechanical level to create a resonance between the thallium electrons and those in the host lead telluride thermoelectric material, depending on the bonds between the atoms.

"It comes down to a peculiar behavior of an electron in a thallium atom when it has tellurium neighbors," he said. "We'd been working for 10 years to engineer this kind of behavior using different kinds of nanostructured materials, but with limited success. Then I saw this paper, and I knew we could do the same thing we'd been trying to do with nanostructures, but with this bulk semiconductor instead."

Heremans designed the new material with Vladimir Jovovic, who did this work for his doctoral thesis in the Department of Mechanical Engineering at Ohio State. Researchers at Osaka University -- Ken Kurosaki, Anek Charoenphakdee, and Shinsuke Yamanaka -- created samples of the material for testing. Then researchers at the California Institute of Technology -- G. Jeffrey Snyder, Eric S. Toberer, and Ali Saramat -- tested the material at high temperatures. Heremans and Jovovic tested it at low temperatures and provided experimental proof that the physical mechanism they postulated was indeed at work.

The team found that near 450 degrees Fahrenheit, the material converted heat to electricity with an efficiency rating of about 0.75 -- close to that of sodium doped telluride. But as the temperature rose, so did the efficiency of the new material. It peaked at 950 degrees Fahrenheit, with a rating of 1.5.

Heremans' team is continuing to work on this patent-pending technology.

"We hope to go much further. I think it should be quite possible to apply other lessons learned from thermoelectric nanotechnology to boost the rating by another factor of two -- that's what we're shooting for now," he said.

This research was funded by the BSST Corporation; the State of Ohio Department of Development's Center for Photovoltaic Innovation and Commercialization at Ohio State University; the Beckman Institute; the Swedish Bengt Lundqvist Minne Foundation; and NASA's Jet Propulsion Laboratory.

####

For more information, please click here

Contacts:
Research Communications
Address 1125 Kinnear Rd.
Columbus, OH 43212-1153
United States
Phone 614-292 8384
Fax 614-292-0154

Joseph Heremans
(614) 247-8869


Vladimir Jovovic
(614) 247-4441


Editor's note: Until July 29, 2008, Heremans will be in Switzerland. He can be reached by email, or by phone at +41-27 771-2026 starting at 12:00 p.m. ET.

Copyright © Ohio State University

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Berkeley Lab Researchers Demonstrate First Size-based Chromatography Technique for the Study of Living Cells April 22nd, 2014

PETA science consortium to present hazard testing strategy at nanotoxicology meeting: High tech field ripe for use of sophisticated non-animal testing strategies April 22nd, 2014

Harris & Harris Group Notes the Receipt of Proceeds From the Sale of Molecular Imprints' Semiconductor Business to Canon April 22nd, 2014

National Space Society Congratulates SpaceX on the Success of CRS-3 and the First Flight of the Falcon 9R April 22nd, 2014

Discoveries

Like a hall of mirrors, nanostructures trap photons inside ultrathin solar cells April 22nd, 2014

Nanomaterial Outsmarts Ions April 22nd, 2014

Vacuum Ultraviolet Lamp of the Future Created in Japan: First Solid-State Vacuum UV Phosphor, Described in APL-Materials, Promises Smaller, Safer, Longer Lasting, Low Power Lamps for Industrial Applications April 22nd, 2014

Berkeley Lab Researchers Demonstrate First Size-based Chromatography Technique for the Study of Living Cells April 22nd, 2014

Announcements

Berkeley Lab Researchers Demonstrate First Size-based Chromatography Technique for the Study of Living Cells April 22nd, 2014

PETA science consortium to present hazard testing strategy at nanotoxicology meeting: High tech field ripe for use of sophisticated non-animal testing strategies April 22nd, 2014

Harris & Harris Group Notes the Receipt of Proceeds From the Sale of Molecular Imprints' Semiconductor Business to Canon April 22nd, 2014

National Space Society Congratulates SpaceX on the Success of CRS-3 and the First Flight of the Falcon 9R April 22nd, 2014

Patents/IP/Tech Transfer/Licensing

Harris & Harris Group Notes Mersana's Collaboration Agreement With Subsidiary of Takeda Pharmaceutical Co. April 8th, 2014

Nanoparticles cause cancer cells to self-destruct April 3rd, 2014

A*STAR's Simtech collaboration agreements to accelerate the growth and development of the microfluidics industry April 1st, 2014

Dolomite releases novel droplet-on-demand sequencing and droplet generation microfluidic system April 1st, 2014

Energy

Like a hall of mirrors, nanostructures trap photons inside ultrathin solar cells April 22nd, 2014

Global leader in solar cell manufacturing eyes New York for major expansion outside of Japan: CNSE and Solar Frontier Explore $700 Million Investment, Job Creation in New York State April 22nd, 2014

Nanoreporters tell 'sour' oil from 'sweet': Rice University's hydrogen sulfide nanoreporters gather intel on oil before pumping April 22nd, 2014

High-temperature plasmonics eyed for solar, computer innovation April 17th, 2014

Automotive/Transportation

Relieving electric vehicle range anxiety with improved batteries: Lithium-sulfur batteries last longer with nanomaterial-packed cathode April 16th, 2014

Tiny particles could help verify goods: Chemical engineers hope smartphone-readable microparticles could crack down on counterfeiting April 15th, 2014

Nanotech Business Review 2013-2014 April 9th, 2014

Heat-conducting polymer cools hot electronic devices at 200 degrees C March 31st, 2014

NanoNews-Digest
The latest news from around the world, FREE







  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More














ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE