Jun 25 2020
According to Smokey Bear, an American campaign and advertising icon of the U.S. Forest Service, only people can prevent wildfires. But what if a high-tech backup can help?
MSU’s Changyong Cao directs the Laboratory for Soft Machines and Electronics. Image Credit: Michigan State University.
As part of a new study, researchers at Michigan State University have designed and developed a remote system for forest fire detection and alarming, which is powered by only the movement of trees in wind.
The device named MC-TENG—short for multilayered cylindrical triboelectric nanogenerator —has been described in the Advanced Functional Materials journal. It produces electrical power by tapping energy from the sporadic movement of the branches of trees from which it hangs.
As far as we know, this is the first demonstration of such a novel MC-TENG as a forest fire detection system. The self-powered sensing system could continuously monitor the fire and environmental conditions without requiring maintenance after deployment.
Changyong Cao, Assistant Professor, School of Packaging, Departments of Mechanical Engineering, and Electrical and Computer Engineering, Michigan State University
Cao, who is the lead author of the study, also directs the Laboratory of Soft Machines and Electronics in the School of Packaging.
According to Cao and his colleagues, this new technology was driven by the tragic forest fires in recent years in the American West, Australia, and Brazil. Cao is convinced that quick and early response to forest fires will render the task of extinguishing easier, thereby considerably reducing the damage and loss of property and life.
Conventional methods for detecting forest fire involve ground patrols, satellite monitoring, watchtowers, etc., which incur high financial and labor costs but are not so efficient.
Existing remote sensor technologies are turning out to be more common, but they mainly depend on battery technology for power.
Although solar cells have been widely used for portable electronics or self-powered systems, it is challenging to install these in a forest because of the shading or covering of lush foliage.
Yaokun Pang, Study Co-Author, Michigan State University
Pang is a postdoc associate at Cao’s lab.
TENG technology transforms external mechanical energy—for example, the movement of a tree branch—into electricity through the triboelectric effect, a phenomenon in which some materials turn electrically charged once they separate from another material with which they were in contact earlier.
The basic version of the TENG device includes two cylindrical sleeves made of exclusive material and fitting within one another. While the core sleeve is anchored from the top, the bottom sleeve freely slides up and down and moves side to side, where it is restricted only by an elastic connective band or spring.
Electricity is produced by the intermittent loss of contact when both the sleeves move out of sync. The MC-TENG devices are fitted with many hierarchical triboelectric layers, thus increasing the electrical output.
The MC-TENG device stores its sporadically produced electrical current in a carbon-nanotube-based micro supercapacitor. The team chose this technology for its quick rapid charge and discharge times, which enables the device to sufficiently charge with just short but sustained gusts of wind.
At a very low vibration frequency, the MC-TENG can efficiently generate electricity to charge the attached supercapacitor in less than three minutes.
Changyong Cao, Assistant Professor, School of Packaging, Departments of Mechanical Engineering, and Electrical and Computer Engineering, Michigan State University
Both temperature and carbon monoxide (CO) sensors were fitted in the initial prototype. The temperature sensor was added to minimize the chances of a false positive carbon dioxide reading.
Other co-authors of the study are doctoral candidate Shoue Chen, undergraduate Junchi An, Keliang Wang, and engineering professors Yiming Deng, Andre Benard, and Nizar Lajnef.
Cao believes the team can field test a production device to track forest environmental conditions and test scenarios, by using materials that simulate a real fire. The researchers also aim to incorporate additional functionality, which would enable the device to be adapted for the weather and environmental conditions where it is deployed.
This study was financially supported in part by the U.S. Department of Agriculture’s National Institute of Food and Agriculture, Michigan Economic Development Corporation, American Society for Nondestructive Testing Faculty Grant Program, and MSU and MSU Technologies.
Journal Reference:
Pang, Y., et al. (2020) Multilayered Cylindrical Triboelectric Nanogenerator to Harvest Kinetic Energy of Tree Branches for Monitoring Environment Condition and Forest Fire. Advanced Functional Materials. doi.org/10.1002/adfm.202003598.