Archive for energy harvesting
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Piezoelectricity’s positive vibrations
Via LiveScience, the Inside Science News Service reports that scientists at the Virginia Polytechnic Institute, in Blacksburg, Va., have recently developed a tiny piezoelectric device that is able to harness the power generated by small vibrations and could become of tremendous use in tomorrow’s small-scale robots, probes and appliances.
Collecting the energy of small vibrations could potentially lead to the development of self-charging batteries. This type of battery could be particular useful inside portable game consoles, mobile phones, laptops or radio instruments. Carrying them around makes them shake and vibrate, albeit on a small scale.The VPI device could harness this energy, and essentially recharge the batteries as the object is being moved from one place to the other in a bag or pocket. Details of the new apparatus appear in the journal Applied Physics Letters.
The breakthrough in this work has to do with getting the piezo devices to function at a wider range of vibration frequencies. They describe their units as “piezomagnetoelastic structures.” Compared to typical piezoelectric devices, the VPI “broadband” energy harvester yielded a 200% increase in the open-circuit voltage amplitude, which should in turn deliver an 800% increase in the power amplitude.
A lot of groups are thinking about new ways to use piezos in energy-harvesting applications, and broadband devices could open up a lot of new applications. For instance, crystals could be placed under highly circulated sidewalks, and could provide the energy requirements of the stores located on that specific street. Essentially, they can be placed anywhere where continuous activity takes place.
The VPI work is being sponsored in part by the Air Force. The USAF plans to use the devices to harness the vibrations that appear at the tip of the wings of unmanned reconnaissance planes. Capturing this energy could allow the vehicles to stay in the air longer. NIST is the other funder, and the agency plans to use the piezoelectrics on bridges, hopefully to harness the power of intense traffic bottlenecks.
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Video of the week: Freescale delivers big power from small solar cells
Via CNET’s Green Tech blog, we bring you a video about some nifty power conversion technology for photovoltaic applications that Freescale Semiconductor unveiled this week at the Applied Power Electronics Conference and Exposition. This is about high efficiency, ultra-low-voltage DC-to-DC converter technology. It enables IC startup thresholds to be reduced to 0.32 V (ICs typically can’t start up at less than 0.7 V) and efficiencies of nearly 90 percent. This method would allow new system design options and the ability to recover energy at ultra-low voltages, e.g., single-cell solar power systems and other energy-harvesting applications, such as thermoelectric and mechanical scavenging systems. “Freescale says applications can include solar-powered battery chargers, trickle chargers for automotive systems, chargers for cell phones and laptops, remote data acquisition and industrial HVAC systems, PV-based traffic signals, solar-powered home and commercial lighting products, and self-powered wireless transponders.”
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Energy harvesting radio-based detection system unveiled
Kansas State University and Peregrine Semiconductors are demonstrating a battery-free technology that could improve embedded multi-sensor systems such as those that might be used to detect deterioration in busy bridge. “This type of radio technology may exist in your house, for instance if you have a temperature sensor outside that radios data to a display inside,” Kuhn said. “But those devices need to have their batteries changed. This radio doesn’t.” Peregrine Semiconductor says applications could include monitoring stress, temperature and pressure on bridges and other structures. K-State and Peregrine have already developed highly integrated, low power radio chips for NASA’s Jet Propulsion Laboratory using Peregrine’s UltraCMOS silicon-on-sapphire technology. The team has constructed a demonstration board using inexpensive solar cells to power the radio, but says they are also looking at piezoelectric, electrochemical and thermal energy approaches.
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