Energy

Selenium Interlayer for High-Efficiency Multi-Junction Solar Cell

This technology can be commercialized for terrestrial applications such as power plants and smart grid systems.

Innovators at NASA’s Glenn Research Center have developed a low-cost, high-efficiency solar cell that uses a thin layer of selenium as the bonding material between wafers. Selenium is a semiconductor, and it is also transparent to light at photon energies below the band gap. The innovation allows a multi-junction solar cell to be developed without the constraint of lattice matching, and uses a low-cost, robust silicon wafer as the supporting bottom substrate and bottom cell. This enables a cell that is simultaneously lower in cost, more rugged, and more efficient than existing space solar cell designs. This technology has the potential to be used in next-generation solar cells in space, and it can be commercialized for terrestrial applications such as power plants and smart grid systems.

Posted in: Briefs, Energy, Solar Power, Solar energy, Joining, Semiconductors, Silicon alloys, Durability, Reliability, Durability, Reliability
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Tethered Vehicle Control and Tracking System

The system enables effective operation of airborne wind energy (AWE) generation systems.

NASA’s Langley Research Center has developed hardware and software to track the flight of tethered vehicles, including kite-like, airborne wind energy (AWE) generation systems. The control system consists of a pan-tilt platform and a visible-spectrum digital camera, combined with tracking control software running on a standard PC. The system controls the flight of the vehicle to keep its position on a power-producing trajectory, maximizing velocity (but within limits). This trajectory produces tension, which turns the ground-based generator, producing the energy. The NASA system enables effective operation of groundgen or flygen types of AWE systems. NASA has a working prototype and pre-beta software, and is seeking development partners to make it more robust and user-friendly by testing it in real-world systems.

Posted in: Briefs, Aerospace, Aviation, Energy, Trajectory control, Computer software / hardware, Computer software and hardware, Imaging, Imaging and visualization, Computer software / hardware, Computer software and hardware, Imaging, Imaging and visualization, Autonomous vehicles
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Preventing Cell-to-Cell Thermal Runaway in Lithium-Ion Battery Modules

Lithium-ion (Li-ion) cells are increasingly used in high-voltage and high-capacity modules. The Li-ion chemistry has the highest energy density of all rechargeable battery chemistries, but associated with that energy is the issue of catastrophic thermal runaway with a fire. With recent incidents in the commercial aerospace and electronics sectors, it was necessary to find methods to prevent cell-to-cell thermal runaway propagation.

Posted in: Briefs, Batteries, Energy, Scale models, Battery cell chemistry, Lithium-ion batteries, Battery cell chemistry, Lithium-ion batteries, Fire prevention
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Breakthrough Energy Innovation: Ambition and Urgency

Climate change goals, customer sustainability expectations and pressure to reduce waste demand ambition and urgency from industry to deliver breakthrough energy innovation. Engineering simulation is a key enabler to achieve these breakthroughs. From startups to multinationals, businesses are using engineering simulation to explore the much broader design spaces in the areas of advanced electrification, machine and fuel efficiency, aerodynamic design, effective lightweighting and thermal optimization.

Posted in: White Papers, Electronics & Computers, Energy, Simulation Software
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Scientists Simulate Bacteria-Powered 'Windfarm'

A team of scientists from Oxford University has shown how the natural movement of bacteria could be harnessed to assemble and power microscopic "windfarms."

Posted in: News, Energy Harvesting, Renewable Energy
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Method and Circuit for In-Situ Health Monitoring of Solar Cells in Space

Potential applications include use in diagnostics for terrestrial solar power generation systems.

NASA’s Glenn Research Center has developed a method and apparatus for in-situ health monitoring of solar cells. The innovation is a novel approach to solar cell monitoring, as it is radiation- hard, consumes few system resources, and uses commercially available components. The system operates at temperatures from –55 to 225 °C, allowing it to reside close to the array in direct sunlight. The circuitry measures solar cell current versus voltage (I-V) curves using relatively inexpensive electronics, a single switchable +28 V power bus, and two analog-to-digital (A/D) converter channels. A single transistor is used as a variable resistive load across the cell, rather than the large resistor arrays or active current sources normally used to characterize cells. Originally developed for space, the technology can be adapted for use in terrestrial solar power generation systems.

Posted in: Briefs, Energy, Solar Power, Integrated circuits, On-board diagnostics, On-board diagnostics (OBD), Transistors, Integrated circuits, On-board diagnostics, On-board diagnostics (OBD), Transistors, Solar energy
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Foldable and Deployable Power Collection System

The lightweight solar power array can be used in electric vehicles, portable and field-deployable power systems, and power for emergency response operations.

NASA’s Marshall Space Flight Center is developing a lightweight space-based solar power array with a high power-to-stowed-volume and weight ratio. The system provides power to small satellites and CubeSats that are power starved, operating on extremely limited power because of the size restrictions for housing onboard power sources. The beauty of NASA’s new solar unit is in its simplicity and packaged power density. Small satellites cannot take advantage of deployable high-efficiency solar cell arrays due to their complexity and mechanical needs; the weight and volume requirements exceed what is available in small satellites and CubeSats. The new system, for example, is compact enough to provide a 3U CubeSat with ~200 Watts, or a 6U with 500 Watts of power. NASA is developing the technology and is looking for partners to license and commercialize it.

Posted in: Briefs, Energy, Solar Power, Physical Sciences, Solar energy, Product development, Satellites
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Solid-State Ultracapacitor

NASA’s Marshall Space Flight Center has developed a solid-state ultracapacitor utilizing a novel nanocomposite dielectric material. The material’s design is based on the internal barrier layer capacitance (IBLC) concept, and it uses novel dielectric and metallic conductive ink formulations.

Posted in: Briefs, Energy, Physical Sciences, Ultracapacitors and supercapacitors, Ultracapacitors and supercapacitors, Composite materials, Nanomaterials
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Double-acting Extremely Light Thermo-Acoustic (DELTA) Converter

This technology enables a new class of lightweight power systems for small aircraft, camping, or micro-cogeneration that is small, quiet, efficient, and essentially maintenance-free.

Power generation from an external or internal heat source using thermal energy conversion technologies such as solid-state thermionics and thermoelectrics or dynamic conversion with Otto, Stirling, Brayton, or Rankine technologies is fundamentally limited in maximum specific power due to either low efficiency and/or operating frequency. These solid-state technologies are low voltage and hence produce a high DC current that restricts their minimum geometry to approximately 4 A/mm2 to avoid overheating. High-power implementations of this technology class are inefficient, large, and heavy.

Posted in: Briefs, Energy, Heat exchangers, Thermal management, Heat exchangers, Thermal management, Product development, Electro-thermal engines, Lightweighting
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Chassis Short Mitigation and Characterization Technique for the Multi-Mission Radioisotope Thermoelectric Generator

The radioisotope thermoelectric generator (RTG) is a flight-proven, capable source of power that reliably converts heat into electricity. NASA and the Department of Energy (DoE) have developed a new generation of such power systems that could be used for a variety of space missions. The newest RTG, called a Multi-Mission Radioisotope Thermoelectric Generator (MMRTG), has been designed to operate on Mars and in the vacuum of space. However, shorts between the internal electrical power circuit and chassis frame of the MMRTG have been observed in the engineering unit, qualification unit, and flight unit. The internal shorts seemed to appear and sometimes clear spontaneously. A root cause has not been determined for these internal shorts, and their resistance, power rating, and energy rating are largely unknown. A mitigation and measurement technique is needed.

Posted in: Briefs, Energy, Failure analysis, Electro-thermal engines, Performance tests, Spacecraft
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