Tag Archives: Internet of Things

How To ConVert Waste Heat Into Electricity

Thermoelectric materials, capable of transforming heat into electricity, are very promising when converting residual heat into electrical energy, since they allow us to utilize hardly usable or almost lost thermal energy in an efficient way. Researchers at the Institute of Materials Science of Barcelona (ICMAB-CSIC) have created a new thermoelectric material: a paper capable of converting waste heat into electricity. These devices could be used to generate electricity from residual heat to feed sensors in the field of the Internet of Things, Agriculture 4.0 or Industry 4.0.


This device is composed of cellulose, produced in situ in the laboratory by bacteria, with small amounts of a conductor nanomaterial, carbon nanotubes, using a sustainable and environmentally friendly strategy” explains Mariano Campoy-Quiles, researcher at the ICMAB.

“In the near future, they could be used as wearable devices, in medical or sports applications, for example. And if the efficiency of the device was even more optimized, this material could lead to intelligent thermal insulators or to hybrid photovoltaic-thermoelectric power generation systems” predicts Campoy-Quiles. In addition “due to the high flexibility of the cellulose and to the scalability of the process, these devices could be used in applications where the residual heat source has unusual forms or extensive areas, as they could be completely covered with this material” indicates Anna Roig, researcher at the ICMAB.

Since bacterial cellulose can be home made, perhaps we are facing the first step towards a new energy paradigm, where users will be able to make their own electric generators. We are still far away, but this study is a beginning. We have to start somewhere. “Instead of making a material for energy, we cultivate it” explains Mariano Campoy-Quiles, a researcher of this study. “Bacteria, dispersed in an aqueous culture medium containing sugars and carbon nanotubes, produce the nanocellulose fibers that will end up forming the device, in which the carbon nanotubes are embedded” continues Campoy-Quiles.”We obtain a mechanically resistant, flexible and deformable material, thanks to the cellulose fibers, and with a high electrical conductivity, thanks to the carbon nanotubes,” adds Anna Laromaine, researcher at the ICMAB. “The intention is to approach the concept of circular economy, using sustainable materials that are not toxic for the environment, which are used in small amounts, and which can be recycled and reused,“says Roig.

The study has been published in the Energy & Environmental Science journal.

Source: http://icmab.es/

Spray-On Electronic Nano-Antennas For Wearables

The promise of wearables, functional fabrics, the Internet of Things, and their “next-generation” technological cohort seems tantalizingly within reach. But researchers in the field will tell you a prime reason for their delayed “arrival” is the problem of seamlessly integrating connection technology — namely, antennas — with shape-shifting and flexible “things.”

But a breakthrough by researchers in Drexel’s College of Engineering, could now make installing an antenna as easy as applying some bug spray. In research recently published in Science Advances, the group reports on a method for spraying invisibly thin antennas, made from a type of two-dimensional, metallic material called MXene, that perform as well as those being used in mobile devices, wireless routers and portable transducers.

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Spray-applied MXene antennas could open the door for new applications in smart technology, wearables and IoT devices

This is a very exciting finding because there is a lot of potential for this type of technology,” said Kapil Dandekar, PhD, a professor of Electrical and Computer Engineering in the College of Engineering, who directs the Drexel Wireless Systems Lab, and was a co-author of the research. “The ability to spray an antenna on a flexible substrate or make it optically transparent means that we could have a lot of new places to set up networks — there are new applications and new ways of collecting data that we can’t even imagine at the moment.”

Source: https://drexel.edu/

High Power Generator Utilizes Thermal Difference Of Only 5ºC

Objects in our daily lives, such as speakers, refrigerators, and even cars, are becoming “smarter” day by day as they connect to the internet and exchange data, creating the Internet of Things (IoT), a network among the objects themselves. Toward an IoT-based society, a miniaturized thermoelectric generator is anticipated to charge these objects, especially for those that are portable and wearable.

Due to advantages such as its relatively low thermal conductance but high electric conductance, silicon nanowires have emerged as a promising thermoelectric material. Silicon-based thermoelectric generators conventionally employed long, silicon nanowires of about 10-100 nanometers, which were suspended on a cavity to cutoff the bypass of the heat current and secure the temperature difference across the silicon nanowires. However, the cavity structure weakened the mechanical strength of the devices and increased the fabrication cost. To address these problems, a team of Japanese researchers from Waseda University, Osaka University, and Shizuoka University designed and successfully developed a novel silicon-nanowire thermoelectric generator, which experimentally demonstrated a high power density of 12 microwatts per 1cm2, enough to drive sensors or realize intermittent wireless communication, at a small thermal difference of only 5ºC.

Because our generator uses the same technology to manufacture semiconductor integrated circuits, its processing cost could be largely cut through mass production,” says Professor Takanobu Watanabe of Waseda University, the leading researcher of this study. “Also, it could open up a pathway to various, autonomously-driven IoT devices utilizing environmental and body heats. For instance, it may be possible to charge your smartwatch during your morning jog someday.”

The newly developed thermoelectric generator lost the cavity structure but instead shortened the silicon nanowires to 0.25 nanometers, since simulations showed that the thermoelectric performance improved by minimizing the device. Professor Watanabe explains that despite its new structure, the new thermoelectric generator demonstrated the same power density as the conventional devices. More surprisingly, thermal resistance was suppressed, and the power density multiplied by ten times by thinning the generator’s silicon substrate from the conventional 750 nanometers to 50 nanometers with backside grinding.

Source: https://www.waseda.jp/