Tiny generators turn waste heat into power

Sep 28, 2010

The second law of thermodynamics is a big hit with the beret-wearing college crowd because of its implicit existential crunch. The tendency of a closed systems to become increasingly disordered if no energy is added or removed is a popular, if not depressing, "things fall apart" sort-of-law that would seem to confirm the adolescent experience.

Now a joint team of Ukrainian and American scientists has demanded more work and less poetry from the , proposing a novel "pyroelectric" method to power tiny devices using waste heat.

Using called ferroelectric nanowires, they can rapidly generate an in response to any change in the , harvesting otherwise wasted energy from thermal fluctuations. Their report appears in the .

Explains lead researcher Anna Morozovska of the National Academy of Sciences of Ukraine, "The second law of thermodynamics rules modern life: Through all kinds of industry, humans consistently produce an enormous amount of . However, the laws of thermodynamics do not exclude rescuing some of this energy by harvesting the thermal fluctuations to produce electricity."

Pyroelectrictricity can play key role in consumer electronics, says Morozovska, and recovering this heat in the form of pyroelectric energy may bring about a new era of "tiny energy." Pyroelectric nanogenerators could be extremely useful for powering specific tasks in biological applications, medicine and nanotechnology, particularly in space because they perform well in low temperatures.

In an investigation of the pyroelectric properties of ferroelectric nanowires, the team analyzed how the pyroelectric coefficient corresponds to the radius of the wire and its coupling. They found that the smaller the wire radius, the more the pyroelectric coefficient diverges until a critical radius at which the response changes to paraelectric (above the Curie temperature). This so-called "size effect" could be used to tune the phase transition temperatures in ferroelectric nanostructures, thus enabling a system with a large, tunable, pyroelectric response.

In theory, the use of rectifying contacts could enable the polarized ferroelectric nanowire to generate a giant, pyroelectric, direct current and voltage in response to temperature fluctuations that could be harvested and detected using a bolometric detector. Such a nanoscale device would not contain any moving parts and could be suitable for long-term operation in ambient applications such as in-vitro biological systems and outer space. The researchers calculate that these little nanogenerators would have very high efficiency at low temperatures, decreasing at warmer temperatures.

Explore further: In-situ nanoindentation study of phase transformation in magnetic shape memory alloys

More information: The article, "Pyroelectric response of ferroelectric nanowires: Size effect and electric energy harvesting" by Anna N. Morozovska, Eugene A. Eliseev, George S. Svechnikov, and Sergei V. Kalinin appears in the Journal of Applied Physics. jap.aip.org/resource/1/japiau/v108/i4/p042009_s1

Provided by American Institute of Physics

4.5 /5 (10 votes)

Related Stories

Could Maxwell's Demon Exist in Nanoscale Systems?

Jun 24, 2009

(PhysOrg.com) -- Maxwell’s demon may be making a comeback. Physicists know that the demon, an imaginary creature that decreases the entropy of a system, cannot exist in macroscopic systems due to the energy ...

New material could efficiently power tiny generators

Oct 22, 2009

(PhysOrg.com) -- To power a very small device like a pacemaker or a transistor, you need an even smaller generator. The components that operate the generator are smaller yet, and the efficiency of those foundational components ...

Promising new material that could improve gas mileage

Oct 09, 2008

With gasoline at high prices, it's disheartening to know that up to three-quarters of the potential energy you are paying for is wasted. A good deal of it goes right out the tailpipe instead of powering your car.

Recommended for you

'Exotic' material is like a switch when super thin

Apr 18, 2014

(Phys.org) —Ever-shrinking electronic devices could get down to atomic dimensions with the help of transition metal oxides, a class of materials that seems to have it all: superconductivity, magnetoresistance ...

User comments : 2

Adjust slider to filter visible comments by rank

Display comments: newest first

Quantum_Conundrum
not rated yet Sep 28, 2010
Is this a team partnered with those from this article below?

"Quantum physicists turn waste heat into power"

Have they discovered a different effect related to waste heat being converted to electricity, or is this based on the same principles?

I gather this could be useful in nano-robots as a primary or secondary power supply either in implants in people or as "maintenance robots" in spacecraft, which would be literally powered by the waste heat from the craft's primary systems.

If these are two unrelated effects then it appears they've just found a huge potential increase in efficiency.

If they are using the same principles then I guess it's two different ways to skin the same cat.
Crates
not rated yet Sep 30, 2010
I think the introduction of this news is somewhat exagerated.

The 2nd principle contains no poetry although many ones have interpreted it in different (questionable) ways.

Moreover in my opinion the article described here does not directly address the 2nd principle but rather the maximisation of the efficiency in electrically active closed systems.

Nice topic of research otherwise and it is useful that physorg advertises it.

More news stories

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Ex-Apple chief plans mobile phone for India

Former Apple chief executive John Sculley, whose marketing skills helped bring the personal computer to desktops worldwide, says he plans to launch a mobile phone in India to exploit its still largely untapped ...

Filipino tests negative for Middle East virus

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

Egypt archaeologists find ancient writer's tomb

Egypt's minister of antiquities says a team of Spanish archaeologists has discovered two tombs in the southern part of the country, one of them belonging to a writer and containing a trove of artifacts including reed pens ...