Scientists at the Max Planck Institute for Solid State Research (Stuttgart, Germany) have announced a design for a practical, highly efficient thermionic generator -- dubbed a "thermoelectronic generator" -- that can convert heat energy into electricity using the difference between a hot and cold metallic plate.
The new design circumvents the "space-charge effect" problem that has limited current flow between the plates in previous attempts by using an electric field to pull the evaporated electrons away from the generator's hot plate (emitter) allowing more of them to reach the cold plate (collector) (see the figures below). According to the researchers, the new design promises an efficiency of about 40% compared to the 10% of previous devices. For more, see the original paper "Highly-Efficient Thermoelectronic Conversion of Solar Energy and Heat into Electric Power."
In this prototype of a thermoelectronic generator, the glowing orange disk (left) shows the back of the resistively heated emitter, while the yellowish disk edge on the right shows the reflection of the glowing emitter on the collector surface.
(Source: J. Mannhart, MPI-FKF)
A view into the prototype thermoelectronic generator, looking at the ~3-cm emitter.
(Source: J. Mannhart, MPI-FKF)
UK-based startup New Wave Energy UK is proposing a new use for aerial drones -- to form the basis of high-altitude (50,000-ft) aerial power plants that harvest solar and wind energy and then beam it wirelessly to ground. The 20 x 20-m drones, which would operate in networks, would each be able to power themselves from solar energy and generate an additional 50 kW (see short video (1:32) below). According to the company, an aerial power plant containing thousands of such drones could produce about 400 MW, and would be twice the size of an offshore wind farm. The company also plans a Kickstarter campaign.
A report from research firm Navigant Research forecasts that the global market for DC-powered building technologies will grow to $9.7 billion in 2020, from $609.1 million in 2013. According to the report -- "DC Power for Commercial Buildings" -- the growth in the use of DC power (and minimization of AC/DC conversions) is being driven by several factors, including the increasing use of renewable energy sources, increasing demand for advanced energy storage devices, and increasing demand for energy efficiency.
In product news, Supertex has introduced a boost DC/DC controller with an output of between 6V and 500V from a battery-level input of 2.7V to 4.5V. The HV9150 includes both a charge pump converter
and a linear regulator and is designed for systems requiring high-voltage and low-current applications.
A new 80-V battery charging controller from Linear Technology for lead acid and lithium batteries features automatic maximum power point tracking (MPPT) and temperature compensation. The LT8490 operates from input voltages above, below or equal to the output voltage and can be powered by a solar panel or a DC supply.
Advanced Power Electronics has introduced a 30-V power MOSFET for use in high-current load switching. Packaged in an industry-standard "5x6" package with heatsink, the AP1A003GMT-HF-3 has a maximum on-resistance of 0.99 mΩ.
A DC/DC boost converter from ams features an ultra-low quiescent current of 1 µA. The AS1312 operates from a 0.7V to 5.0V supply, with an output voltage fixed in 50-mV steps from 2.5V to 5.0V.
Finally, a family of single-channel gate driver ICs from Infineon provide 1200-V isolation and up to 6 A of output. The 1EDI EiceDriver Compact family is available in five variants with separate source/sink outputs for MOSFETs and IGBTs, and three different output-current variants.