Power Generation and Storage
Power Generation and Storage
The development of devices, processes and systems that generate and store electrical, mechanical or fluid power or energy.
NEW CFC Front Image
Cryogenic Flux Capacitor
Storage and transfer of fluid commodities such as oxygen, hydrogen, natural gas, nitrogen, argon, etc. is an absolute necessity in virtually every industry on Earth. These fluids are typically contained in one of two ways; as low pressure, cryogenic liquids, or as a high pressure gases. Energy storage is not useful unless the energy can be practically obtained ("un-stored") as needed. Here the goal is to store as many fluid molecules as possible in the smallest, lightest weight volume possible; and to supply ("un-store") those molecules on demand as needed in the end-use application. The CFC concept addresses this dual storage/usage problem with an elegant charging/discharging design approach. The CFC's packaging is ingeniously designed, tightly packing aerogel composite materials within a container allows for a greater amount of storage media to be packed densely and strategically. An integrated conductive membrane also acts as a highly effective heat exchanger that easily distributes heat through the entire container to discharge the CFC quickly, it can also be interfaced to a cooling source for convenient system charging; this feature also allows the fluid to easily saturate the container for fast charging. Additionally, the unit can be charged either with cryogenic liquid or from an ambient temperature gas supply, depending on the desired manner of refrigeration. Finally, the heater integration system offers two promising methods, both of which have been fabricated and tested, to evenly distribute heat throughout the entire core, both axially and radially.
Spy fixed-wing drone
Double-Acting Extremely Light Thermo-Acoustic (DELTA) Convertor
Glenn's innovative DELTA convertor uses a double-action push/pull piston, in which an acoustic wave - or sound wave generated by heat - pushes both ends of a single piston. When sound waves are propagated down a narrow tube, they transfer energy along the tube. Conversely, when a heat gradient is introduced, it will generate sound waves that will cause the push/pull piston to oscillate. Using thermoacoustics to oscillate the push/pull piston simplifies engine operation by eliminating moving parts such as hot displacers and heavy springs. The double-action piston is contained by multiple thermo-acoustic stages in series that form a delta-shaped triangular loop. One side of the piston creates an acoustic wave while simultaneously receiving acoustic power on the opposing side, enabling increased power on the single piston as compared to a single-action piston. The simple design consists of a helium-filled tube, heat exchangers, regenerators, and a single, non-contact, oscillating piston. Operating at 400Hz, this convertor can produce four times more power than conventional engines operating at 100Hz, with no hot moving parts, maintenance, lubrication, or electric feedback required. At this higher frequency, the output current is minimized and the specific power is maximized enabling an order of magnitude increase in specific power over conventional engines. Glenn's novel DELTA convertor offers this significantly increased specific power in a compact, lightweight, maintenance-free package that has considerable commercial potential.
Green Car
Graphene Composite Materials for Supercapacitor Electrodes
The method is a two-step, low-cost, scalable solution process of reduced graphene oxide (rGO) and transition metal oxide nanostructures. The deposition of a hybrid metal oxide composite layer of Co304 and Mn02 is done on a current collecting substrate, followed by the electrophoretic deposition of a graphene oxide (GO) top layer. This top GO layer is then chemically reduced, allowing for significant conductivity while creating a porous, high surface area layer atop themetaloxide layer. Reduction typically is accomplished through the use of chemical agents, like hydrazine and sodium borohydride, or by high temperature treatments. The approach uses sodium borohydride as a supplementary reduction method. The variety of methods by which the hybrid metal oxide nanocomposite layer may be deposited onto different current collecting substrates makes this arrangement extremely attractive. Metal oxide nanowire arrays can be deposited using a huge variety of hydrothermal and electrodeposition methods. This range of methods by which the metal oxide component can be deposited onto a conductive substrate also allows for a high degree of flexibility in choosing of the current collecting substrate. The high porosity of the rGO layer is of great importance to allow sufficient diffusion of ions into and out of the metal oxide composite layer. The high specific area of the rGO allows for a high capacitive contribution from the Electrical Double Layer (EDL), while the metal oxide layer provides for a significant increase to the overall energy density of the electrode.
Solar Panels
Stirling Thermoacoustic Power Converter and Magnetostrictive Alternator
Glenn's thermoacoustic power converter reshapes the conventional Stirling engine from a toroidal shape into a straight colinear arrangement. Instead of relying on failure-prone mechanical inertance and compliance tubes, this design achieves acoustical resonance by using electronic components. In a typical Stirling engine, the acoustical wave travels around a toroid and reflects back, forming a standing wave. In Glenn's device, by contrast, the wave instead travels in a straight plane where a transducer receives the acoustical wave and electrical components modulate the signal. A second transducer on the diametrically opposed side reintroduces the acoustic wave with the correct phasing to achieve amplification and resonance. Glenn's design allows the transducers to operate at high frequency while presenting a mass rather than stiffness impedance. Glenn's magnetostrictive alternator uses stacked magnetostrictive materials under a biased magnetic and stress-induced compression. The acoustic energy from the engine travels through an impedance-matching layer (which can be formed from aerogel materials) that is physically connected to the magnetostrictive mass. Compression bolts keep the structure under compressive strain, allowing for the micron-scale compression of the magnetostrictive material and eliminating the need for bearings. The alternating compression and expansion of the magnetostrictive material creates an alternating magnetic field that then induces an electric current in a coil wound around the stack. This alternator produces electrical power from the acoustic pressure wave and, when the resonant frequency is tuned to match the engine, can replace the linear alternator to great effect.
NASA Plane
Double-Fed Induction Linear Alternator
This technology was developed to address the limitations of traditional, single-fed linear alternators, which require permanent magnets, adhesive bonding organics, and heavy iron laminations for flux control. They experience eddy-current losses and require electromagnetic interference protection. Furthermore, they have a limited operational temperature range (only up to 250°C), which typically declines to below 200°C as the adhesive bonding organics outgas and degrade over time. Consequently, they are limited to approximately 93% efficiency at ambient temperatures. Glenn's novel linear alternator addresses all of the limitations of its predecessors and engenders a number of desirable new qualities - notably the ability to reduce eddy-current losses by 25% and operate at 99% efficiency at temperatures up to 950°C. It features a concentric, additively manufactured monolithic copper plunger and stator. The stator is a stationary single copper Halbach array, whereas the plunger is a moving electromagnetic copper Halbach array. A direct current is delivered through the conductive piston flexure support, which also provides reactive power for resonance. It creates a fixed magnetic field similar to that of a permanent magnet, but the magnetic field is channeled inward by the Halbach mover, doubling its strength. By utilizing standard double-fed induction control methods, the reactive power can be transferred and adjusted between both coils. This maximizes system efficiency and minimizes weight. This innovative technology will enable a new class of vastly superior linear alternators with the ability to operate at extreme temperatures with increased performance and efficiency. This is an early-stage technology requiring additional development. Glenn welcomes co-development opportunities.
GRC Pre-mix Burner
Premixed, High-Pressure, Multi-Fuel Burner
NASA Glenn's fully premixed burner design accomplishes the rapid mixing of the fuel and air flows while simultaneously providing backside impingement cooling to the burner face. This novel burner technology has been demonstrated to operate on hydrogen-air mixtures at pressures up to 30 bar, and at equivalence ratios (Phi) ranging from 0.15 to 5.0, but typically at equivalence ratios below 0.6 or above 2.0 for extended periods of time. It has also been demonstrated to work well with hydrogen-carbon monoxide fuel mixtures in a 1:1 mixture (by volume). The design provides a uniform zone of combustion products and temperatures, and is able to achieve complete and rapid mixing of the reactant gases over a distance as short as 5 mm, with the combustion products attaining a fully-reacted state within about 10 mm downstream of the burner face. Effectiveness of the mixing is not dependent on the use of hydrogen gas, therefore the system works well for other gaseous fuels such as methane, propane, or natural gas, in a fully premixed mode. The design of the Glenn's burner is simple and straightforward to manufacture using conventional techniques. The modular design of the burner lends itself to scalability for larger power output applications. This burner is simple to operate and is robust for use in an industrial setting such as low-emissions stationary gas turbine engine, or for aircraft gas turbine engines.
Carbon Nanotube
Carbon Nanotube Tower-Based Supercapacitor
This invention provides a four-part system that includes: (1) first and second, spaced-apart planar collectors; (2) first and second arrays of Multi-Wall Carbon Nanotube (MWCNT) towers, serving as electrodes, that extend between the first and second collectors, where the MWCNT towers are grown directly on the collector surfaces without deposition of a catalyst or a binder material on the collectors surface; (3) a separator module having a transverse area that is substantially the same as the transverse area of either electrode; and (4) at least one MWCNT tower that acts as a hydrophilic structure with improved surface wettability. The growth of MWCNT and/or Single Wall Carbon Nanotube (SWCNT) towers is done directly on polished, ultra-smooth alloy substrates containing iron and or nickel, such as nichrome, kanthal and stainless steel. The growth process for generating an MWCNT tower array requires heating the collector metal substrate in an inert argon gas atmosphere to 750 C. After thermal equilibration, 1000 sccm of 8/20 ethylene/Hs gas flow results in the growth of carbon nanotube towers.
Space Station
High-Efficiency Solar Cell
This NASA Glenn innovation is a novel multi-junction photovoltaic cell constructed using selenium as a bonding material sandwiched between a thin film multi-junction wafer and a silicon substrate wafer, enabling higher efficiencies. A multi-junction photovoltaic cell differs from a single junction cell in that it has multiple sub-cells (p-n junctions) and can convert more of the sun's energy into electricity as the light passes through each layer. To further improve the efficiencies, this cell has three junctions, where the top wafer is made from high solar energy absorbing materials that form a two-junction cell made from the III-V semiconductor family, and the bottom substrate remains as a simple silicon wafer. The selenium interlayer is applied between the top and bottom wafers, then pressure annealed at 221°C (the melting temperature of selenium), then cooled. The selenium interlayer acts as a connective layer between the top cell that absorbs the short-wavelength light and the bottom silicon-based cell that absorbs the longer wavelengths. The three-junction solar cell manufactured using selenium as the transparent interlayer has a higher efficiency, converting more than twice the energy into electricity than traditional cells. To obtain even higher efficiencies of over 40%, both the top and bottom layers can be multi-junction solar cells with the selenium layer sandwiched in between. The resultant high performance multi-junction photovoltaic cell with the selenium interlayer provides more power per unit area while utilizing a low-cost silicon-based substrate. This unprecedented combination of increased efficiency and cost savings has considerable commercial potential. This is an early-stage technology requiring additional development. Glenn welcomes co-development opportunities.
Thin film device for harvesting energy from wind
Compliant electrode and composite materials for piezoelectric wind and mechanical energy conversions
The NASA researchers integrated two innovations into this unique piezoelectric device. First, they combined polyvinylidene flouride (PVDF) with a metal oxide to improve conductance. Second, they designed a new carbon-electrode to improve durability (compliance) and reduce susceptibility to fatigue while retaining flexibility. Additionally, to integrate the carbon nanotube components, they use a polymer-to-polymer design that eliminates the need for adhesion layers. A prototype device generated 1 W power (at 15 mph wind) with a single layer of PVDF [4 inch by 12 inch and 50 um (micrometer) thick] sandwiched between two thin electrode films. A rectifier converts the AC signal into a DC signal and stores the charge in a capacitor. This electric power can be used for low power consuming devices, such an inaccessible sensors.
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