DIR Return Create A Forum - Home
       ---------------------------------------------------------
       Renewable Revolution
  HTML https://renewablerevolution.createaforum.com
       ---------------------------------------------------------
       *****************************************************
   DIR Return to: New Inventions
       *****************************************************
       #Post#: 5662--------------------------------------------------
       Clothing that Generates Electricity
       By: AGelbert Date: September 12, 2016, 1:55 pm
       ---------------------------------------------------------
       [center]Lightweight, wearable tech efficiently converts body
       heat to electricity[/center]
       September 12, 2016 by Matt Shipman
       [center][img
       width=640]
  HTML https://3c1703fe8d.site.internapcdn.net/newman/gfx/news/hires/2016/lightweightw.jpg[/img][/center]
       NC State University researchers have developed a new design for
       harvesting body heat and converting it into electricity for use
       in wearable electronics. The experimental prototypes are
       lightweight, conform to the shape of the body, and can generate
       far more electricity than previous lightweight heat harvesting
       technologies. This image shows the technology embedded in a
       T-shirt (left) and armband (right). Credit: Daryoosh Vashaee
       Researchers at North Carolina State University have developed a
       new design for harvesting body heat and converting it into
       electricity for use in wearable electronics. The experimental
       prototypes are lightweight, conform to the shape of the body,
       and can generate far more electricity than previous lightweight
       heat harvesting technologies.
       The researchers also identified the optimal site on the body for
       heat harvesting.
       "Wearable thermoelectric generators (TEGs) generate electricity
       by making use of the temperature differential between your body
       and the ambient air," says Daryoosh Vashaee, an associate
       professor of electrical and computer engineering at NC State and
       corresponding author of a paper on the work. "Previous
       approaches either made use of heat sinks—which are heavy, stiff
       and bulky—or were able to generate only one microwatt or less of
       power per centimeter squared (μW/cm2). Our technology
       generates up to 20 μW/cm2 and doesn't use a heat sink,
       making it lighter and much more comfortable."
       The new design begins with a layer of thermally conductive
       material that rests on the skin and spreads out the heat. The
       conductive material is topped with a polymer layer that prevents
       the heat from dissipating through to the outside air. This
       forces the body heat to pass through a centrally-located TEG
       that is one cm2. Heat that is not converted into electricity
       passes through the TEG into an outer layer of thermally
       conductive material, which rapidly dissipates the heat. The
       entire system is thin—only 2 millimeters—and flexible.
       "In this prototype, the TEG is only one centimeter squared, but
       we can easily make it larger, depending on a device's power
       needs," says Vashaee, who worked on the project as part of the
       National Science Foundation's Nanosystems Engineering Research
       Center for Advanced Self-Powered Systems of Integrated Sensors
       and Technologies (ASSIST) at NC State.
       [center][img
       width=640]
  HTML https://3c1703fe8d.site.internapcdn.net/newman/gfx/news/hires/2016/1-lightweightw.jpg[/img][/center]
       Study co-lead Haywood Hunter, shows off the TEG-embedded T-shirt
       at work. Credit: Daryoosh Vashaee
       The researchers also found that the upper arm was the optimal
       location for heat harvesting. While the skin temperature is
       higher around the wrist, the irregular contour of the wrist
       limited the surface area of contact between the TEG band and the
       skin. Meanwhile, wearing the band on the chest limited air
       flow—limiting heat dissipation—since the chest is normally
       covered by a shirt.
       In addition, the researchers incorporated the TEG into T-shirts.
       The researchers found that the T-shirt TEGs were still capable
       of generating 6 μW/cm2 - or as much as 16 μW/cm2 if a
       person is running.
       "T-shirt TEGs are certainly viable for powering wearable
       technologies, but they're just not as efficient as the upper arm
       bands," Vashaee says.
       "The goal of ASSIST is to make wearable technologies that can be
       used for long-term health monitoring, such as devices that track
       heart health or monitor physical and environmental variables to
       predict and prevent asthma attacks," he says.
       "To do that, we want to make devices that don't rely on
       batteries. And we think this design and prototype moves us much
       closer to making that a reality."
       [i]The paper, "Wearable thermoelectric generators for human body
       heat harvesting," is published in the journal Applied Energy.
       Explore further: Electricity from body heat
       More information: Melissa Hyland et al, Wearable thermoelectric
       generators for human body heat harvesting, Applied Energy
       (2016). DOI: 10.1016/j.apenergy.2016.08.150
       Provided by North Carolina State University [/I]
  HTML https://techxplore.com/news/2016-09-lightweight-wearable-tech-efficiently-body.html
       *****************************************************