A lightweight, flexible thermoelectric fabric called Power Felt could generate enough electricity from body heat to power a small electronic device, like an iPod, or iPhone.
The fabric, composed of carbon nanotube/polymer thin films, was developed by a team headed by researchers at Wake Forest University's Center for Nanotechnology and Molecular Materials. Power Felt generates an electrical charge from temperature differences, converting thermal to electrical energy. Examples include the difference between room temperature and body temperature, or between the temperature of a jacket liner next to the body and that of a jacket exterior exposed to cold air. Alternately, the fabric could be layered under roof shingles, line car seats, be wrapped around hot water pipes, or be integrated into a wound wrap to power medical monitors.
Alternating p-type (red) and n-type (green) nanotube/polymer heterogeneous thin films, with insulating polymer films (blue) between the conduction layers, form a lightweight, flexible fabric that could generate enough electricity from body heat to power portable electronic devices. (Source: Wake Forest University)
The fabric consists of a carbon nanotube/polymer composite thin film comprising multiple layers of multiwalled carbon nanotubes and polyvinylidene fluoride. The multiple layers are alternating p-type and n-type nanotube/polymer heterogeneous thin films with insulating polymer film layers between conduction layers. Layers are pressed together vertically and heated to about 425K to 450K to melt the polymer enough to bond the layers together and form a felt-like fabric. The resulting thermoelectric voltage results in increased power output as layers are added.
Generating electricity with thermoelectric material requires high efficiency levels. High-efficiency materials, usually made from bismuth telluride, have been used for CPU cooling and mobile refrigerators, but their cost (as much as $1,000 per kilogram) makes them too expensive for high-volume consumer applications. The researchers say Power Felt can be less expensive to manufacture, lighter, and easier to process than bismuth telluride, so it is more suitable for a number of applications, including portable electronics.
Wow, this is really cool stuff. Think about all the crazy applications and gear that would come out by taking advantage of this technology. I would imagine beyond powering up simple consumer devices, there could be huge applicability for life-saving medical applications.
Another interesting application of carbon nanotubes.This is a very interesting technology, and very appropriate for so many of the devices we use every day.With the advent of platforms that use ultra-low power processors the applications should be wide.It is also interesting to contemplate using the waste heat from a device to power that device.
Years ago there was a push on for ubiquitous, wearable computing devices.These were seen as wearable computing platforms.This is a technology that might help bring that area of research back.
Another interesting aspect of this is the parallel with nuclear space power.Although there have been active nuclear power generation systems for space, these have been rare.One of the issues, of course, was the moving machinery.The most common type of nuclear space power is the RTG, or Radioisotope Thermal Generator, converted a delta-T to a delta-V. And there are no moving parts. These are the devices that power the interplanetary flights.The principle is the same, but the materials completely different.Of course, you would not want to wear a RTG since the heat source is pure plutonium.
There do seem to be a lot of interesting and novel materials applications coming out that are based on, or incorporate, CNTs as an important ingredient. I wrote about some early methods for constructing CNTs about a decade ago and wondered how long it would take to see them start to be actually used.
naperlou, I remember the push for wearable devices you are referring to. It actually wasn't that long ago, a decade or less. I seem to remember that keeping them powered was a problem. Looks like we're getting closer to that solution.
Nice article, Ann. One thing I like about this material is that it's not based on movement or vibration. The U.S. Military is using a wearable generator attached to the boot. But it requires movement. The self-charging batteries for remote sensors rely on vibration. A power generator based on temperature variations wouldn't require motion or vibration. Cool.
Thanks Rob. Good point about not needing movement to activate energy harvesting, like that Army boot. OTOH, considering the amount of walking around soldiers do, it makes sense that the military would be looking at apps that harvest energy from movement. And also considering the lack of exercise many people get, it might make more sense to motivate us by working on movement-activated energy harvesting for consumer devices. I guess it makes sense to have different technologies that can harvest different kinds of energy.
Ann, if such innovations are happening, it’s a bonus for the gadget users. Most of us experience the power crunch, while using phones/IPad/ Smartphones. So whenever the battery power goes down below a certain level, it can be recharges immediately from the fabric, wonderful idea and hope then onwards no power drain.
Energy harvesting is the need of he hour. Autonomous systems with energy harvesting will offer better workflow soultions and that will in turn result in better products. I am working on a structural health monitoring system with energy harvesting and I know and I am sure like this wearable fabric may other invention will soon see the light of the day in coming days.
To the user wearing the fabric it would provide a cooling effect. This would be advantagious for the foot soldier, especially when also wearing the boot generator. Overall efficiency is increased when both are employed together.
In an age of globalization and rapid changes through scientific progress, two of our societies' (and economies') main concerns are to satisfy the needs and wishes of the individual and to save precious resources. Cloud computing caters to both of these.
For industrial control applications, or even a simple assembly line, that machine can go almost 24/7 without a break. But what happens when the task is a little more complex? That’s where the “smart” machine would come in. The smart machine is one that has some simple (or complex in some cases) processing capability to be able to adapt to changing conditions. Such machines are suited for a host of applications, including automotive, aerospace, defense, medical, computers and electronics, telecommunications, consumer goods, and so on. This discussion will examine what’s possible with smart machines, and what tradeoffs need to be made to implement such a solution.