Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Temperature differences give rise to electricity

HOT AND COLD WATER: Ole Martin Løvvik demonstrates thermoelectricity with one glass of cold and one glass of hot water. The new technology utilises the temperature difference and generates enough energy to operate a rapidly rotating fan. Foto: Yngve Vogt
HOT AND COLD WATER: Ole Martin Løvvik demonstrates thermoelectricity with one glass of cold and one glass of hot water. The new technology utilises the temperature difference and generates enough energy to operate a rapidly rotating fan. Foto: Yngve Vogt

Abstract:
Over half of all the energy in the world is lost as useless waste heat. Much of this heat loss can now be converted to electricity.

Temperature differences give rise to electricity

Oslo, Norway | Posted on November 9th, 2011

Tekst: Yngve Vogt

More than half of today's energy consumption is squandered in useless waste heat, such as the heat from refrigerators and all sorts of gadgets and the heat from factories and power plants. The energy losses are even greater in cars. Automobile motors only manage to utilise 30 per cent of the energy they generate. The rest of it is lost. Part of the heat loss ends up as warm brakes and a hot exhaust pipe.

Scientists at the Centre for Materials Science and Nanotechnology at the University of Oslo in Norway (UiO) are now collaborating with SINTEF (the Foundation for Scientific and Industrial Research at the Norwegian Institute of Technology) to develop a new environmentally friendly technology called thermoelectricity, which can convert waste heat to electricity. To put it briefly, the technology involves making use of temperature differences.

Today: Toxic and expensive.

Thermoelectric materials are put to many uses in space flight. When a space probe travels far enough away from the sun, its solar cells cease to work. Batteries have much too short a lifetime. Nuclear power cannot be used. However, a lump of Plutonium will do the trick.

With a temperature of a thousand degrees, it is hot. Outer space is cold. Thanks to the temperature difference, the space probe gets enough electricity.

Plutonium is a good solution for space probes that will not return to earth, but it is not a practical solution for cars and other earthly objects.

Thermoelectric materials are also currently used in the type of cooler bags that keep things cold without making use of their own cooling elements. These cooler bags are full of the elements Lead and Tellurium. Both of these substances are also toxic.

"We want to replace them with inexpensive and readily available substances. Moreover, there is not enough Tellurium to equip all of the cars in the world," says Ole Martin Løvvik, who is both an associate professor in the Department of Physics at the University of Oslo and a senior scientist at SINTEF.


Tomorrow: Environmentally friendly and inexpensive.

With the current technology, it is possible to recover scarcely ten per cent of the lost energy. Together with the team of scientists led by Professor Johan Taftø, Løvvik is now searching for pollution-free, inexpensive materials that can recover fifteen per cent of all energy losses. That is an improvement of fully fifty per cent.

"I think we will manage to solve this problem with nanotechnology. The technology is simple and flexible and is almost too good to be true. In the long run, the technology can utilise all heat sources, such as solar energy and geothermal energy. The only limits are in our imagination," states Løvvik.

The new technology will initially be put to use in thermoelectric generators in cars. Several major automobile manufacturers are already interested. Løvvik and his colleagues are currently discussing the situation with General Motors.

"Modern cars need a lot of electricity. By covering the exhaust system with thermoelectric plates, the heat from the exhaust system can increase the car's efficiency by almost ten per cent at a single stroke. If we succeed, this will be a revolution in the modern automotive industry."

The new technology can also replace the hum of today's refrigerator.

"In the future, refrigerators can be soundless and built into cabinets without any movable parts and with the possibility of maintaining different temperatures in each compartment.

In order to extract as much energy as possible, the temperature difference should be as large as possible.

"Initially then, we want to utilise high-temperature waste heat, but there is also an upper limit."

If it becomes too hot, some materials will break down either by melting or by being transformed into other materials. That would mean that they wouldn't work any more.

Apparently self-contradictory.

In order to create thermoelectric materials, physicists have to resolve an apparent paradox. A metal conducts both electricity and heat. An insulator conducts neither electricity nor heat.

A good thermoelectric material ought to be a semi-conductor with very special properties: Its thermal resistance must be as high as possible at the same time as current must flow through it easily.

"This is not a simple combination, and it may even sound like a self-contradiction. The best solution is to create small structures that reflect the heat waves at the same time as the current is not reflected."

In order to understand why this is so, you must first understand how heat is dissipated. When a material becomes hot, the atoms vibrate. The hotter it becomes, the greater the vibrations, and when an atom vibrates, it will also affect the vibration of the adjacent atom.

When these vibrations spread through the material, they can be called heat waves. If we create barriers in the material so that some atoms vibrate at different frequencies from their adjacent atoms, the heat will not be so easily dissipated.

"Moreover, the atomic barrier must be created in such a way that it does not prevent the electric current from flowing through it."


Grinding nano-cavities at minus 196 degrees.

The scientists have found a method of creating these atomic barriers. The barriers are introduced densely in the special semi-conductors.

"We have achieved this by using a completely new "mill". Just as the miller grinds grain, the scientists will grind down semi-conductors to nano-sized grains. They will do that by cooling them down with liquid Nitrogen to minus 196 degrees. That makes the material more brittle, less sticky and easier to crush. It is important to grind down the grains as small as possible. Afterwards the grains are glued back together again, and in this way the barriers are created."

"The small irregularities in the barriers reflect the heat waves," says Løvvik.

The team of scientists uses an electron microscope to examine the micro-structures in the material.

"We have now discovered new nano-cavities in the materials and learned more about how they reflect heat waves."

The thermal resistance is measured in the Norwegian Micro and Nano Laboratories that are jointly operated by UiO and SINTEF. Løvvik's specialised field is mathematical models. With these models, he can predict how the atoms should be arranged in the materials.

Renaissance for Cobalt.

The scientists are now searching for the next generation of thermoelectric materials. They have just tested the cobalt arsenide mineral, skutterudite, which may be found at Skutterud at Blåfarveværket in Modum, Norway.

"It was just recently discovered that skutterudite may have atoms located in small nano-cavities. These cavities act as barriers to heat dissipation," concludes Løvvik.

Thermoelectric materials make use of temperature differences.

The thermal resistance must be as high as possible at the same time as the current must flow through easily.

The University of Oslo is studying environmentally friendly, inexpensive thermoelectric materials that can recover 15 per cent of all energy losses.

The automotive industry is already interested.

####

For more information, please click here

Copyright © University of Oslo

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

Imaging electric charge propagating along microbial nanowires October 20th, 2014

Design of micro and nanoparticles to improve treatments for Alzheimers and Parkinsons: At the Faculty of Pharmacy of the UPV/EHU-University of the Basque Country encapsulation techniques are being developed to deliver correctly and effectively certain drugs October 20th, 2014

Physicists build reversible laser tractor beam October 20th, 2014

Removal of Limitations of Composites at Superheat Temperatures October 20th, 2014

Physics

Solid nanoparticles can deform like a liquid: Unexpected finding shows tiny particles keep their internal crystal structure while flexing like droplets October 12th, 2014

Unconventional photoconduction in an atomically thin semiconductor: New mechanism of photoconduction could lead to next-generation excitonic devices October 9th, 2014

Nanoparticles Break the Symmetry of Light October 6th, 2014

Quantum environmentalism: Putting a qubit's surroundings to good use October 2nd, 2014

Discoveries

Imaging electric charge propagating along microbial nanowires October 20th, 2014

Design of micro and nanoparticles to improve treatments for Alzheimers and Parkinsons: At the Faculty of Pharmacy of the UPV/EHU-University of the Basque Country encapsulation techniques are being developed to deliver correctly and effectively certain drugs October 20th, 2014

Physicists build reversible laser tractor beam October 20th, 2014

Removal of Limitations of Composites at Superheat Temperatures October 20th, 2014

Announcements

Imaging electric charge propagating along microbial nanowires October 20th, 2014

Design of micro and nanoparticles to improve treatments for Alzheimers and Parkinsons: At the Faculty of Pharmacy of the UPV/EHU-University of the Basque Country encapsulation techniques are being developed to deliver correctly and effectively certain drugs October 20th, 2014

Physicists build reversible laser tractor beam October 20th, 2014

Removal of Limitations of Composites at Superheat Temperatures October 20th, 2014

Tools

New Grand ARM Transmission Electron Microscope Offers Highest Commercially-Available Atomic Resolution of 63 Picometers October 17th, 2014

Nanodevices for clinical diagnostic with potential for the international market: The development is based on optical principles and provides precision and allows saving vital time for the patient October 15th, 2014

Nanotronics Imaging Releases nSPEC® 3D, Powerful Microscope That Captures 3D Images at Nanoscale, in Lightning Speed: Company Unveils Design at American Chemical Society 2014 International Elastomer Conference October 14th, 2014

Unique catalysts for hydrogen fuel cells synthesized in ordinary kitchen microwave oven October 14th, 2014

Energy

First Canada Excellence Research Chair gets $10 million from the federal government for oilsands research at the University of Calgary: Federal government announces prestigious research chair to study improving oil production efficiency October 19th, 2014

Magnetic mirrors enable new technologies by reflecting light in uncanny ways October 16th, 2014

Unique catalysts for hydrogen fuel cells synthesized in ordinary kitchen microwave oven October 14th, 2014

Dyesol Signs Letter of Intent with Tata Steel October 13th, 2014

Automotive/Transportation

Production of Anticorrosive Chromate Nanocoatings in Iran September 27th, 2014

Teijin Aramid’s carbon nanotube fibers awarded with Paul Schlack prize: New generation super fibers bring wave of innovations to fiber market September 25th, 2014

Next-Gen Luxury RV From Global Caravan Technologies Will Offer MagicView Roof and Windshield Using SPD-SmartGlass Technology From Research Frontiers: Recreational Vehicle Manufacturer Global Caravan Technologies (GCT) Features 28 Square Feet of MagicView™ SPD-SmartGlass September 17th, 2014

Toward making lithium-sulfur batteries a commercial reality for a bigger energy punch September 17th, 2014

Battery Technology/Capacitors/Generators/Piezoelectrics/Thermoelectrics/Energy storage

Graphenea opens US branch October 16th, 2014

NTU develops ultra-fast charging batteries that last 20 years October 14th, 2014

Electrically conductive plastics promising for batteries, solar cells October 10th, 2014

Crumpled graphene could provide an unconventional energy storage: Two-dimensional carbon “paper” can form stretchable supercapacitors to power flexible electronic devices October 4th, 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