Nanowerk March 8, 2022 In thermoelectric materials the hot side can be easily obtained by excess heat. Since thermoelectric voltage is proportional to the temperature difference between the hot and cold sides, efficient passive cooling to increase the temperature gradient is of critical importance. Researchers in Japan have designed a magnetic hybrid system where radiative cooling occurs at the top, as heat is lost from a material in the form of infrared radiation, while solar radiation is absorbed at the bottom. They demonstrated this concept by using the spin Seebeck effect. The device shows the highest thermoelectric voltage when both […]
Category Archives: Energy harvesting
Metasurface-based antenna turns ambient radio waves into electric power
Phys.org February 28, 2022 Researchers at the South Florida University have demonstrated a high-efficiency RF energy harvesting device based on a metamaterial perfect absorber (MPA). With the embedded Schottky diodes, the MPA-based rectenna converts captured RF waves to DC power. The Fabry-Perot (FP) cavity resonance of the MPA greatly improved the amount of energy captured. The FP resonance exhibited a high Q-factor and significantly increased the voltage across the Schottky diodes, which improved the rectification efficiency, particularly at low intensity. This led to a factor of 16 improvement of RF-DC conversion efficiency at ambient intensity level. According to the researchers […]
Chemists discover new way to harness energy from ammonia
Phys.org November 11, 2021 Researchers at the University of Wisconsin developed a technique to convert ammonia to nitrogen gas using a metal catalyst containing ruthenium without added energy. The process can be harnessed to produce electricity, with protons and nitrogen gas as byproducts. In addition, the metal complex can be recycled through exposure to oxygen and used repeatedly, a much cleaner process than using carbon-based fuels. The new reaction avoids toxic byproducts. If the reaction were housed in a fuel cell where ammonia and ruthenium react at an electrode surface, it could cleanly produce electricity without the need for a […]
Energy harvesting technology based on ferromagnetic resonance
Phys.org August 24, 2021 Researchers in Japan demonstrated electrical charging using the electromotive force (EMF) generated in a ferromagnetic metal (FM) film under ferromagnetic resonance (FMR). In the case of Ni80Fe20 films, electrical charge due to the EMF generated under FMR can be accumulated in a capacitor; however, the amount of charge is saturated well below the charging limit of the capacitor. In the case of Co50Fe50, electrical charge generated under FMR can be accumulated in a capacitor and the amount of charge increases linearly with the FMR duration time. The difference between the Ni80Fe20 and Co50Fe50 films is due […]
Engineers harvest WiFi signals to power small electronics
Nanowerk May 18, 2021 Widespread use of the 2.4GHz radio frequency that uses WiFi has made excess signals available to be tapped for alternative uses. An international team of researchers (Singapore, India, Japan) has demonstrated electrical synchronization of four non-vortex uniformly magnetized spin-torque oscillators (STOs) using a single common current source in both parallel and series configurations at 2.4 GHz band, resolving the frequency-area quandary for designing STO based on-chip communication systems. The synchronized STOs showed an excellent time-domain stability and substantially improved phase noise performance. By integrating the electrically connected eight STOs, they demonstrated the battery-free energy-harvesting system utilizing the […]
Good vibrations for new energy
Nanowerk October 20, 2020 Triboelectric nanogenerators (TENGs) can be made at low cost in different configurations, making them suitable for driving small electronics such as mobile phones, biomechanics devices, and sensors. Researchers in Australia provide experimental and theoretical models for augmented rotary TENGs. The power generated by TENGs is found to be a function of the number of segments, rotational speed, and tribo-surface spacing. They applied mathematical modeling combined with artificial intelligence to characterize the TENG output under various kinematics and geometric conditions. Sensitivity analysis reveals that the generated energy and the matched resistance depend highly on segmentation and angular […]
Easy-to-make, ultra-low power electronics could charge out of thin air
Nanowerk October 14, 2020 An international team of researchers (China, UK, Saudi Arabia) has developed a technology that delivers high-performance electronic circuits based on thin-film transistors which are ‘ambipolar’ in deep subthreshold region. The ‘deep-subthreshold ambipolar’ refers to unprecedented ultra-low operating voltages and power consumption levels. They created printed electronics that meet the power and voltage requirements of real-world applications and opened opportunities for remote sensing and ‘place-and-forget’ devices that can operate without batteries for their entire lifetime. The ultra-low-power printed electronics are simple and cost-effective to manufacture. It can be scaled up to make inexpensive battery-less devices that could […]
This tiny device can scavenge wind energy from the breeze you make when you walk
TechXplore September 23, 2020 A breeze as gentle as 1.6 m/s (3.6 mph) was enough to power the triboelectric nanogenerator designed by an international team of researchers (China, Singapore). The nanogenerator performs at its best when wind velocity is between 4 to 8 m/s (8.9 to 17.9 mph), a speed that allows the two plastic strips to flutter in sync.[see embedded video]. The device also has a high wind-to-energy conversion efficiency of 3.23%. Currently the device can power up 100 LED lights and temperature sensors. Unlike wind turbines, this device is made of low-cost materials and it can be safely […]
These Underwater Drones Use Water Temperature Differences To Recharge
IEEE Spectrum September 3, 2020 Many of the robotic gliders and floating sensor stations currently monitoring the world’s oceans are effectively treated as disposable devices. A team of researchers in the US is developing an underwater recharging station for oceangoing drones incorporating self-insulating electrical connector capable of operating while the powered electrical contacts are submerged. They tap phase change caused by the temperature differences between warmer water at the ocean surface and colder water at the ocean depths to generate electricity. By attaching an external energy-harvesting module they have transformed robotic probes into assets that can be recharged and reused […]
Study offers new insights for sun-gathering technologies
Phys.org August 24, 2020 The direct integration of electrocatalysts with photovoltaic materials provides a strategy to photoelectrochemically power chemical transformations and store intermittent solar energy as fuels. Researchers at the Arizona State University highlight how optical and electrochemical characterization techniques can be coupled with structural information to address to what extent does a selected electrocatalytic coating screen photons from reaching the underlying photovoltaic; coating layers contribute to photocurrent production; and are relatively high or low loadings of catalytic sites advantageous. They used p-type gallium phosphide semiconductor that is interfaced with cobalt porphyrin hydrogen evolution reaction catalysts. Experimental techniques can likely […]