Nav: Home

Study shows the potential of carbon nanotubes to cool electronic circuits

April 24, 2019

The use of solid-state refrigerators to cool appliances and electronic devices is a possible technological application for a theoretical study conducted at the University of Campinas (UNICAMP) in São Paulo State, Brazil.

Although this application is not contemplated by the study, which was based on computer simulations, such applications are on the horizon and could be an efficient and environmentally friendly alternative to vapor-compression refrigerators, which currently dominate the market and contribute to ozone depletion and global warming.

The study, led by Alexandre Fonseca with participation by his former student Tiago Cantuário, was part of the project "Carbon nanostructures: modeling and simulations", supported by São Paulo Research Foundation - FAPESP. The results are published in an article in the journal Annalen der Physik.

"Solid-state cooling is a young field of research with promising results. The method we investigated is based on the so-called elastocaloric effect (ECE), which makes use of temperature variations in a system in response to mechanical stress. We performed computer simulations of this effect in carbon nanotubes," Fonseca told.

In the macroscopic world, an analogous effect is observed when a rubber band warms up as it is rapidly stretched and cools down again as it is released. The effect occurs if the deformation is applied to the material so that there is no heat transfer into or out of the system, i.e., when the process is adiabatic.

"We began our research on the basis of an article entitled 'Elastocaloric effect in carbon nanotubes and graphene', published in 2016 by Sergey Lisenkov and collaborators. It described a computer simulation study showing that when a small deformation was applied to carbon nanotubes, corresponding to up to 3% of their initial length, they responded with a temperature variation of up to 30 °C," Fonseca said.

"In contrast with Lisenkov's research, which simulated only simple strain and compressive force applied to the nanotubes, we reproduced the process computationally for a complete thermodynamic cycle. In our simulation, we considered two phases - nanotube strain and release - and two heat exchanges with two external reservoirs. We estimated the heat that would be extracted by the nanotube if it was in ideal contact with a certain medium. We obtained a good result for the performance coefficient compared with those of other experimentally tested materials."

The performance coefficient is defined as the heat extracted by a system from a given region divided by the energy expended to do so. In the case of a household refrigerator, for example, it shows the amount of heat extracted by the appliance from the internal environment in proportion to the electricity consumed. The best household refrigerators have performance coefficients on the order of 8, meaning they transfer eight times more thermal energy from inside to outside than the amount of electricity extracted from the supply grid to perform the exchange.

"Simulating the process for two different nanotubes, we obtained performance coefficients of 4.1 and 6.5. These are relatively good numbers compared with those for other heat exchange phenomena," Fonseca explained.

Another advantage relates to atomic and molecular structure. "In the case of certain materials, the application of tensile strength makes the sample change phase by modifying its crystal structure. In the case of nanotubes, the thermal effect is due solely to expansion and relaxation of the structure, which is not modified. This is an advantage because phase changes make the material gradually lose its capacity to effect the function of interest. In the case of nanotubes, however, the process doesn't produce any structural transformations capable of causing defects. The atoms are separated during expansion and return to their original positions with relaxation," he said.


According to Fonseca, rupture tests have shown carbon nanotubes to be capable of stretching as much as 20%. This deformation resistance combined with high performance in elastocaloric effects makes carbon nanotubes interesting materials for the development of nanoscale electronics.

"The core problem in electronics is cooling. Our motivation was imagining a device that could use a simple cycle to extract heat from an appliance. Carbon nanotubes proved highly promising," he said. "They also have another virtue, which is that they're small enough to be embedded in a polymer matrix, a desirable property at a time when manufacturers are investing in research and development to obtain flexible electronic devices such as foldable smartphones." All this is part of a larger picture in which vapor-compression refrigerators are replaced by solid-state refrigerators in the context of global climate change.
About São Paulo Research Foundation (FAPESP)

The São Paulo Research Foundation (FAPESP) is a public institution with the mission of supporting scientific research in all fields of knowledge by awarding scholarships, fellowships and grants to investigators linked with higher education and research institutions in the State of São Paulo, Brazil. FAPESP is aware that the very best research can only be done by working with the best researchers internationally. Therefore, it has established partnerships with funding agencies, higher education, private companies, and research organizations in other countries known for the quality of their research and has been encouraging scientists funded by its grants to further develop their international collaboration. You can learn more about FAPESP at and visit FAPESP news agency at to keep updated with the latest scientific breakthroughs FAPESP helps achieve through its many programs, awards and research centers. You may also subscribe to FAPESP news agency at

Fundação de Amparo à Pesquisa do Estado de São Paulo

Related Carbon Nanotubes Articles:

New production method for carbon nanotubes gets green light
A new method of producing carbon nanotubes -- tiny molecules with incredible physical properties used in touchscreen displays, 5G networks and flexible electronics -- has been given the green light by researchers, meaning work in this crucial field can continue.
Growing carbon nanotubes with the right twist
Researchers synthetize nanotubes with a specific structure expanding previous theories on carbon nanotube growth.
Research shows old newspapers can be used to grow carbon nanotubes
New research has found that old newspaper provide a cheap and green solution for the bulk production of single walled carbon nanotubes.
Clean carbon nanotubes with superb properties
Scientists at Aalto University, Finland, and Nagoya University, Japan, have found a new way to make ultra-clean carbon nanotube transistors with superior semiconducting properties.
Dietary fiber effectively purifies carbon nanotubes
A dietary fiber can help separate out semiconducting carbon nanotubes used for making transistors for flexible electronics.
Why modified carbon nanotubes can help the reproducibility problem
Scientists at Tokyo Institute of Technology (Tokyo Tech) conducted an in-depth study on how carbon nanotubes with oxygen-containing groups can be used to greatly enhance the performance of perovskite solar cells.
Tensile strength of carbon nanotubes depends on their chiral structures
Single-walled carbon nanotubes should theoretically be extremely strong, but it remains unclear why their experimental tensile strengths are lower and vary among nanotubes.
New study reveals carbon nanotubes measurement possible for the first time
Swansea University scientists report an entirely new approach to manipulation of carbon nanotubes that allows physical measurements to be made on carbon nanotubes that have previously only been possible by theoretical computation.
Neural networks will help manufacture carbon nanotubes
A team of scientists from Skoltech's Laboratory of Nanomaterials proposed a neural-network-based method for monitoring the growth of carbon nanotubes, preparing the ground for a new generation of sophisticated electronic devices.
Efficient, interconnected, stable: New carbon nanotubes to grow neurons
Carbon nanotubes able to take on the desired shapes thanks to a special chemical treatment, called crosslinking and, at the same time, able to function as substrata for the growth of nerve cells, finely tuning their growth and activity.
More Carbon Nanotubes News and Carbon Nanotubes Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

There's so much we've yet to explore–from outer space to the deep ocean to our own brains. This hour, Manoush goes on a journey through those uncharted places, led by TED Science Curator David Biello.
Now Playing: Science for the People

#555 Coronavirus
It's everywhere, and it felt disingenuous for us here at Science for the People to avoid it, so here is our episode on Coronavirus. It's ok to give this one a skip if this isn't what you want to listen to right now. Check out the links below for other great podcasts mentioned in the intro. Host Rachelle Saunders gets us up to date on what the Coronavirus is, how it spreads, and what we know and don't know with Dr Jason Kindrachuk, Assistant Professor in the Department of Medical Microbiology and infectious diseases at the University of Manitoba. And...
Now Playing: Radiolab

Dispatch 1: Numbers
In a recent Radiolab group huddle, with coronavirus unraveling around us, the team found themselves grappling with all the numbers connected to COVID-19. Our new found 6 foot bubbles of personal space. Three percent mortality rate (or 1, or 2, or 4). 7,000 cases (now, much much more). So in the wake of that meeting, we reflect on the onslaught of numbers - what they reveal, and what they hide.  Support Radiolab today at