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Sample records for photovoltaic energy converter

  1. Thermionic photovoltaic energy converter

    NASA Technical Reports Server (NTRS)

    Chubb, D. L. (Inventor)

    1985-01-01

    A thermionic photovoltaic energy conversion device comprises a thermionic diode mounted within a hollow tubular photovoltaic converter. The thermionic diode maintains a cesium discharge for producing excited atoms that emit line radiation in the wavelength region of 850 nm to 890 nm. The photovoltaic converter is a silicon or gallium arsenide photovoltaic cell having bandgap energies in this same wavelength region for optimum cell efficiency.

  2. Semiconductor electrolyte photovoltaic energy converter

    NASA Technical Reports Server (NTRS)

    Anderson, W. W.; Anderson, L. B.

    1975-01-01

    Feasibility and practicality of a solar cell consisting of a semiconductor surface in contact with an electrolyte are evaluated. Basic components and processes are detailed for photovoltaic energy conversion at the surface of an n-type semiconductor in contact with an electrolyte which is oxidizing to conduction band electrons. Characteristics of single crystal CdS, GaAs, CdSe, CdTe and thin film CdS in contact with aqueous and methanol based electrolytes are studied and open circuit voltages are measured from Mott-Schottky plots and open circuit photo voltages. Quantum efficiencies for short circuit photo currents of a CdS crystal and a 20 micrometer film are shown together with electrical and photovoltaic properties. Highest photon irradiances are observed with the GaAs cell.

  3. Parametric study of laser photovoltaic energy converters

    NASA Technical Reports Server (NTRS)

    Walker, G. H.; Heinbockel, J. H.

    1987-01-01

    Photovoltaic converters are of interest for converting laser power to electrical power in a space-based laser power system. This paper describes a model for photovoltaic laser converters and the application of this model to a neodymium laser silicon photovoltaic converter system. A parametric study which defines the sensitivity of the photovoltaic parameters is described. An optimized silicon photovoltaic converter has an efficiency greater than 50 percent for 1000 W/sq cm of neodymium laser radiation.

  4. Combination solar photovoltaic heat engine energy converter

    NASA Technical Reports Server (NTRS)

    Chubb, Donald L.

    1987-01-01

    A combination solar photovoltaic heat engine converter is proposed. Such a system is suitable for either terrestrial or space power applications. The combination system has a higher efficiency than either the photovoltaic array or the heat engine alone can attain. Advantages in concentrator and radiator area and receiver mass of the photovoltaic heat engine system over a heat-engine-only system are estimated. A mass and area comparison between the proposed space station organic Rankine power system and a combination PV-heat engine system is made. The critical problem for the proposed converter is the necessity for high temperature photovoltaic array operation. Estimates of the required photovoltaic temperature are presented.

  5. Strained quantum well photovoltaic energy converter

    NASA Technical Reports Server (NTRS)

    Freundlich, Alexandre (Inventor); Renaud, Philippe (Inventor); Vilela, Mauro Francisco (Inventor); Bensaoula, Abdelhak (Inventor)

    1998-01-01

    An indium phosphide photovoltaic cell is provided where one or more quantum wells are introduced between the conventional p-conductivity and n-conductivity indium phosphide layer. The approach allows the cell to convert the light over a wider range of wavelengths than a conventional single junction cell and in particular convert efficiently transparency losses of the indium phosphide conventional cell. The approach hence may be used to increase the cell current output. A method of fabrication of photovoltaic devices is provided where ternary InAsP and InGaAs alloys are used as well material in the quantum well region and results in an increase of the cell current output.

  6. Mathematical modeling of a photovoltaic-laser energy converter for iodine laser radiation

    NASA Technical Reports Server (NTRS)

    Walker, Gilbert H.; Heinbockel, John H.

    1987-01-01

    Space-based laser power systems will require converters to change laser radiation into electricity. Vertical junction photovoltaic converters are promising devices for this use. A promising laser for the laser power station is the t-C4F9I laser which emits radiation at a wavelength of 1.315 microns. This paper describes the results of mathematical modeling of a photovoltaic-laser energy converter for use with this laser. The material for this photovoltaic converter is Ga(53)In(47)As which has a bandgap energy of 0.94 eV, slightly below the energy of the laser photons (0.943 eV). Results of a study optimizing the converter parameters are presented. Calculated efficiency for a 1000 vertical junction converter is 42.5 percent at a power density of 1 x 10 to the 3d power w/sq cm.

  7. High-efficiency, monolithic, multi-bandgap, tandem, photovoltaic energy converters

    DOEpatents

    Wanlass, Mark W

    2014-05-27

    A monolithic, multi-bandgap, tandem solar photovoltaic converter has at least one, and preferably at least two, subcells grown lattice-matched on a substrate with a bandgap in medium to high energy portions of the solar spectrum and at least one subcell grown lattice-mismatched to the substrate with a bandgap in the low energy portion of the solar spectrum, for example, about 1 eV.

  8. High-efficiency, monolithic, multi-bandgap, tandem photovoltaic energy converters

    DOEpatents

    Wanlass, Mark W.

    2011-11-29

    A monolithic, multi-bandgap, tandem solar photovoltaic converter has at least one, and preferably at least two, subcells grown lattice-matched on a substrate with a bandgap in medium to high energy portions of the solar spectrum and at least one subcell grown lattice-mismatched to the substrate with a bandgap in the low energy portion of the solar spectrum, for example, about 1 eV.

  9. Performance characteristics of a combination solar photovoltaic heat engine energy converter

    NASA Technical Reports Server (NTRS)

    Chubb, Donald L.

    1987-01-01

    A combination solar photovoltaic heat engine converter is proposed. Such a system is suitable for either terrestrial or space power applications. The combination system has a higher efficiency than either the photovoltaic array or the heat engine alone can attain. Advantages in concentrator and radiator area and receiver mass of the photovoltaic heat engine system over a heat-engine-only system are estimated. A mass and area comparison between the proposed space station organic Rankine power system and a combination PV-heat engine system is made. The critical problem for the proposed converter is the necessity for high temperature photovoltaic array operation. Estimates of the required photovoltaic temperature are presented.

  10. Three-dimensional models of conventional and vertical junction laser-photovoltaic energy converters

    NASA Technical Reports Server (NTRS)

    Heinbockel, John H.; Walker, Gilbert H.

    1988-01-01

    Three-dimensional models of both conventional planar junction and vertical junction photovoltaic energy converters have been constructed. The models are a set of linear partial differential equations and take into account many photoconverter design parameters. The model is applied to Si photoconverters; however, the model may be used with other semiconductors. When used with a Nd laser, the conversion efficiency of the Si vertical junction photoconverter is 47 percent, whereas the efficiency for the conventional planar Si photoconverter is only 17 percent. A parametric study of the Si vertical junction photoconverter is then done in order to describe the optimum converter for use with the 1.06-micron Nd laser. The efficiency of this optimized vertical junction converter is 44 percent at 1 kW/sq cm.

  11. Thermophotovoltaic energy converters based on thin film selective emitters and InGaAs photovoltaic cells

    SciTech Connect

    Fatemi, N.S.; Hoffman, R.H.; Wilt, D.M.; Lowe, R.A.; Garverick, L.M.; Scheiman, D.

    1996-02-01

    This paper presents the results of an investigation to demonstrate thermophotovoltaic energy conversion using InGaAs photovoltaic cells, yttrium-aluminum-garnet- (YAG-) based selective emitters, and bandpass/reflector filters, with the heat source operating at 1100{degree}C. InGaAs cells were grown on InP by organometallic vapor phase epitaxy with bandgaps of 0.60 and 0.75 eV and coupled to Ho-, Er-, and Er-Tm-doped YAG selective emitters. Infrared reflector and/or shortpass filters were also used to increase the ratio of in-band to out-of-band radiation from the selective emitters. Efficiencies as high as 13.2{percent} were recorded for filtered converters. {copyright} {ital 1996 American Institute of Physics.}

  12. Hybrid thermionic-photovoltaic converter

    NASA Astrophysics Data System (ADS)

    Datas, A.

    2016-04-01

    A conceptual device for the direct conversion of heat into electricity is presented. This concept hybridizes thermionic (TI) and thermophotovoltaic (TPV) energy conversion in a single thermionic-photovoltaic (TIPV) solid-state device. This device transforms into electricity both the electron and photon fluxes emitted by an incandescent surface. This letter presents an idealized analysis of this device in order to determine its theoretical potential. According to this analysis, the key advantage of this converter, with respect to either TPV or TI, is the higher power density in an extended temperature range. For low temperatures, TIPV performs like TPV due to the negligible electron flux. On the contrary, for high temperatures, TIPV performs like TI due to the great enhancement of the electron flux, which overshadows the photon flux contribution. At the intermediate temperatures, ˜1650 K in the case of this particular study, I show that the power density potential of TIPV converter is twice as great as that of TPV and TI. The greatest impact concerns applications in which the temperature varies in a relatively wide range, for which averaged power density enhancement above 500% is attainable.

  13. Photovoltaic energy

    NASA Astrophysics Data System (ADS)

    1990-01-01

    In 1989, the U.S. photovoltaic industry enjoyed a growth rate of 30 percent in sales for the second year in a row. This sends a message that the way we think about electricity is changing. Instead of big energy projects that perpetuate environmental and economic damage, there is a growing trend toward small renewable technologies that are well matched to end-user needs and operating conditions. As demand grows and markets expand, investment capital will be drawn to the industry and new growth trends will emerge. The photovoltaic industry around the world achieved record shipments also. Worldwide shipments of photovoltaic (PV) modules for 1989 totaled more than 40 megawatts (MW), nearly a 20 percent increase over last year's shipments. The previous two years showed increases in worldwide shipments of 23 and 25 percent, respectively. If this growth rate continues through the 1990s, as industry back orders would indicate, 300 to 1000 MW of PV-supplied power could be on line by 2000. Photovoltaic systems have low environmental impact and they are inexpensive to operate and maintain. Using solid-state technology, PV systems directly convert sunlight to electricity without high-temperature fluids or moving parts that could cause mechanical failure. This makes the technology very reliable.

  14. High voltage photovoltaic power converter

    DOEpatents

    Haigh, Ronald E.; Wojtczuk, Steve; Jacobson, Gerard F.; Hagans, Karla G.

    2001-01-01

    An array of independently connected photovoltaic cells on a semi-insulating substrate contains reflective coatings between the cells to enhance efficiency. A uniform, flat top laser beam profile is illuminated upon the array to produce electrical current having high voltage. An essentially wireless system includes a laser energy source being fed through optic fiber and cast upon the photovoltaic cell array to prevent stray electrical signals prior to use of the current from the array. Direct bandgap, single crystal semiconductor materials, such as GaAs, are commonly used in the array. Useful applications of the system include locations where high voltages are provided to confined spaces such as in explosive detonation, accelerators, photo cathodes and medical appliances.

  15. Monolithic, multi-bandgap, tandem, ultra-thin, strain-counterbalanced, photovoltaic energy converters with optimal subcell bandgaps

    SciTech Connect

    Wanlass, Mark W.; Mascarenhas, Angelo

    2012-05-08

    Modeling a monolithic, multi-bandgap, tandem, solar photovoltaic converter or thermophotovoltaic converter by constraining the bandgap value for the bottom subcell to no less than a particular value produces an optimum combination of subcell bandgaps that provide theoretical energy conversion efficiencies nearly as good as unconstrained maximum theoretical conversion efficiency models, but which are more conducive to actual fabrication to achieve such conversion efficiencies than unconstrained model optimum bandgap combinations. Achieving such constrained or unconstrained optimum bandgap combinations includes growth of a graded layer transition from larger lattice constant on the parent substrate to a smaller lattice constant to accommodate higher bandgap upper subcells and at least one graded layer that transitions back to a larger lattice constant to accommodate lower bandgap lower subcells and to counter-strain the epistructure to mitigate epistructure bowing.

  16. Photovoltaic converters for solar-pumped lasers

    NASA Technical Reports Server (NTRS)

    Walker, Gilbert H.; Heinbockel, John H.

    1988-01-01

    The authors describe a mathematical parametric study of converters used to convert laser radiation to electricity for space-based laser power systems. Two different lasers, the 1.06-micron Nd laser and the 1.315-micron iodine laser, are used in the vertical junction converter. The calculated efficiency is 50 percent for a 100-junction Si photovoltaic converter when used with a Nd laser. The calculated efficiency for a 1000-junction Ga(0.53)In(0.47)As photovoltaic converter is 43 percent when used with an iodine laser.

  17. Photovoltaic conversion of laser energy

    NASA Technical Reports Server (NTRS)

    Stirn, R. J.

    1976-01-01

    The Schottky barrier photovoltaic converter is suggested as an alternative to the p/n junction photovoltaic devices for the conversion of laser energy to electrical energy. The structure, current, output, and voltage output of the Schottky device are summarized. The more advanced concepts of the multilayer Schottky barrier cell and the AMOS solar cell are briefly considered.

  18. Highly efficient spin-conversion effect leading to energy up-converted electroluminescence in singlet fission photovoltaics

    PubMed Central

    Pandey, Ajay K.

    2015-01-01

    Free charge generation in donor-acceptor (D-A) based organic photovoltaic diodes (OPV) progresses through formation of charge-transfer (CT) and charge-separated (CS) states and excitation decay to the triplet level is considered as a terminal loss. On the other hand a direct excitation decay to the triplet state is beneficial for multiexciton harvesting in singlet fission photovoltaics (SF-PV) and the formation of CT-state is considered as a limiting factor for multiple triplet harvesting. These two extremes when present in a D-A system are expected to provide important insights into the mechanism of free charge generation and spin-character of bimolecular recombination in OPVs. Herein, we present the complete cycle of events linked to spin conversion in the model OPV system of rubrene/C60. By tracking the spectral evolution of photocurrent generation at short-circuit and close to open-circuit conditions we are able to capture spectral changes to photocurrent that reveal the triplet character of CT-state. Furthermore, we unveil an energy up-conversion effect that sets in as a consequence of triplet population build-up where triplet-triplet annihilation (TTA) process effectively regenerates the singlet excitation. This detailed balance is shown to enable a rare event of photon emission just above the open-circuit voltage (VOC) in OPVs. PMID:25585937

  19. Highly efficient spin-conversion effect leading to energy up-converted electroluminescence in singlet fission photovoltaics.

    PubMed

    Pandey, Ajay K

    2015-01-01

    Free charge generation in donor-acceptor (D-A) based organic photovoltaic diodes (OPV) progresses through formation of charge-transfer (CT) and charge-separated (CS) states and excitation decay to the triplet level is considered as a terminal loss. On the other hand a direct excitation decay to the triplet state is beneficial for multiexciton harvesting in singlet fission photovoltaics (SF-PV) and the formation of CT-state is considered as a limiting factor for multiple triplet harvesting. These two extremes when present in a D-A system are expected to provide important insights into the mechanism of free charge generation and spin-character of bimolecular recombination in OPVs. Herein, we present the complete cycle of events linked to spin conversion in the model OPV system of rubrene/C60. By tracking the spectral evolution of photocurrent generation at short-circuit and close to open-circuit conditions we are able to capture spectral changes to photocurrent that reveal the triplet character of CT-state. Furthermore, we unveil an energy up-conversion effect that sets in as a consequence of triplet population build-up where triplet-triplet annihilation (TTA) process effectively regenerates the singlet excitation. This detailed balance is shown to enable a rare event of photon emission just above the open-circuit voltage (V(OC)) in OPVs. PMID:25585937

  20. Highly efficient spin-conversion effect leading to energy up-converted electroluminescence in singlet fission photovoltaics

    NASA Astrophysics Data System (ADS)

    Pandey, Ajay K.

    2015-01-01

    Free charge generation in donor-acceptor (D-A) based organic photovoltaic diodes (OPV) progresses through formation of charge-transfer (CT) and charge-separated (CS) states and excitation decay to the triplet level is considered as a terminal loss. On the other hand a direct excitation decay to the triplet state is beneficial for multiexciton harvesting in singlet fission photovoltaics (SF-PV) and the formation of CT-state is considered as a limiting factor for multiple triplet harvesting. These two extremes when present in a D-A system are expected to provide important insights into the mechanism of free charge generation and spin-character of bimolecular recombination in OPVs. Herein, we present the complete cycle of events linked to spin conversion in the model OPV system of rubrene/C60. By tracking the spectral evolution of photocurrent generation at short-circuit and close to open-circuit conditions we are able to capture spectral changes to photocurrent that reveal the triplet character of CT-state. Furthermore, we unveil an energy up-conversion effect that sets in as a consequence of triplet population build-up where triplet-triplet annihilation (TTA) process effectively regenerates the singlet excitation. This detailed balance is shown to enable a rare event of photon emission just above the open-circuit voltage (VOC) in OPVs.

  1. Solar Photovoltaic Energy.

    ERIC Educational Resources Information Center

    Ehrenreich, Henry; Martin, John H.

    1979-01-01

    The goals of solar photovoltaic technology in contributing to America's future energy needs are presented in this study conducted by the American Physical Society. Although the time needed for photovoltaics to become popular is several decades away, according to the author, short-range applications are given. (Author/SA)

  2. Thermionic energy converters

    DOEpatents

    Monroe, Jr., James E.

    1977-08-09

    A thermionic device for converting nuclear energy into electrical energy comprising a tubular anode spaced from and surrounding a cylindrical cathode, the cathode having an outer emitting surface of ruthenium, and nuclear fuel on the inner cylindrical surface. The nuclear fuel is a ceramic composition of fissionable material in a metal matrix. An axial void is provided to collect and contain fission product gases.

  3. Parametric energy converter

    SciTech Connect

    Johnson, R.N.

    1981-10-20

    A method and apparatus for converting thermal energy into mechanical energy by parametric pumping of rotary inertia. In a preferred embodiment, a modified tesla turbine rotor is positioned within a rotary boiler along its axis of rotation. An external heat source, such as solar radiation, is directed onto the outer casing of the boiler to convert the liquid to steam. As the steam spirals inwardly toward the discs of the rotor, the moment of inertia of the mass of steam is reduced to thereby substantially increase its kinetic energy. The laminar flow of steam between the discs of the rotor transfers the increased kinetic energy to the rotor which can be coupled out through an output shaft to perform mechanical work. A portion of the mechanical output can be fed back to maintain rotation of the boiler.

  4. Thermionic energy converters

    NASA Technical Reports Server (NTRS)

    Morris, J. F. (Inventor)

    1983-01-01

    The efficiency of thermionic energy converters is improved by internal distribution of tiny sorted cesium diodes driven by the thermal gradient between the primary emitter and the collector. The tiny, sorted diode distribution comprises protrusions of the emitter material from the main emitter face which contact the main collector face thermally but not electrically. The main collector ends of the protrusions are separated from the main collector by a thin layer of insulation, such as aluminum oxide. The shorted tiny diode distribution augments cesium ionization through internal thermal effects only within the main diode. No electrical inputs are required. This ionization enhancement by the distribution of the tiny shorted diodes not only reduces the plasma voltage drop but also increases the power output and efficiency of the overall thermionic energy converter.

  5. Cycloidal Wave Energy Converter

    SciTech Connect

    Stefan G. Siegel, Ph.D.

    2012-11-30

    This program allowed further advancing the development of a novel type of wave energy converter, a Cycloidal Wave Energy Converter or CycWEC. A CycWEC consists of one or more hydrofoils rotating around a central shaft, and operates fully submerged beneath the water surface. It operates under feedback control sensing the incoming waves, and converts wave power to shaft power directly without any intermediate power take off system. Previous research consisting of numerical simulations and two dimensional small 1:300 scale wave flume experiments had indicated wave cancellation efficiencies beyond 95%. The present work was centered on construction and testing of a 1:10 scale model and conducting two testing campaigns in a three dimensional wave basin. These experiments allowed for the first time for direct measurement of electrical power generated as well as the interaction of the CycWEC in a three dimensional environment. The Atargis team successfully conducted two testing campaigns at the Texas A&M Offshore Technology Research Center and was able to demonstrate electricity generation. In addition, three dimensional wave diffraction results show the ability to achieve wave focusing, thus increasing the amount of wave power that can be extracted beyond what was expected from earlier two dimensional investigations. Numerical results showed wave cancellation efficiencies for irregular waves to be on par with results for regular waves over a wide range of wave lengths. Using the results from previous simulations and experiments a full scale prototype was designed and its performance in a North Atlantic wave climate of average 30kW/m of wave crest was estimated. A full scale WEC with a blade span of 150m will deliver a design power of 5MW at an estimated levelized cost of energy (LCOE) in the range of 10-17 US cents per kWh. Based on the new results achieved in the 1:10 scale experiments these estimates appear conservative and the likely performance at full scale will

  6. FEMP Renewable Energy Fact Sheet: Photovoltaics

    SciTech Connect

    1999-10-01

    Photovoltaic energy systems, which convert sunlight to electricity, can meet many different needs in Federal facilities. This fact sheet describes how photovoltaic (PV) energy systems can be used to provide electricity for lighting, communications, refrigeration, fans, signs, pumps, drilling equipment, emergency power packs, and cathodic (corrosion) protection, among others. Applications for PV power in Federal facilities include staff housing, parking areas, campgrounds, marinas, visitor centers, roadside communications equipment, ranger stations, underground pipelines, irrigation and disinfecting systems, and disaster response units. PV systems are particularly suitable and cost-effective for facilities that now use diesel power or that are in remote areas far from electric power lines.

  7. Gallium phosphide energy converters

    NASA Technical Reports Server (NTRS)

    Sims, P. E.; Dinetta, L. C.; Goetz, M. A.

    1995-01-01

    Gallium phosphide (GaP) energy converters may be successfully deployed to provide new mission capabilities for spacecraft. Betavoltaic power supplies based on the conversion of tritium beta decay to electricity using GaP energy converters can supply long term low-level power with high reliability. High temperature solar cells, also based on GaP, can be used in inward-bound missions greatly reducing the need for thermal dissipation. Results are presented for GaP direct conversion devices powered by Ni-63 and compared to the conversion of light emitted by tritiarated phosphors. Leakage currents as low as 1.2 x 10(exp -17) A/sq cm have been measured and the temperature dependence of the reverse saturation current is found to have ideal behavior. Temperature dependent IV, QE, R(sub sh), and V(sub oc) results are also presented. These data are used to predict the high-temperature solar cell and betacell performance of GaP devices and suggest appropriate applications for the deployment of this technology.

  8. Switching coordination of distributed dc-dc converters for highly efficient photovoltaic power plants

    DOEpatents

    Agamy, Mohammed; Elasser, Ahmed; Sabate, Juan Antonio; Galbraith, Anthony William; Harfman Todorovic, Maja

    2014-09-09

    A distributed photovoltaic (PV) power plant includes a plurality of distributed dc-dc converters. The dc-dc converters are configured to switch in coordination with one another such that at least one dc-dc converter transfers power to a common dc-bus based upon the total system power available from one or more corresponding strings of PV modules. Due to the coordinated switching of the dc-dc converters, each dc-dc converter transferring power to the common dc-bus continues to operate within its optimal efficiency range as well as to optimize the maximum power point tracking in order to increase the energy yield of the PV power plant.

  9. Electromagnetic wave energy converter

    NASA Technical Reports Server (NTRS)

    Bailey, R. L. (Inventor)

    1973-01-01

    Electromagnetic wave energy is converted into electric power with an array of mutually insulated electromagnetic wave absorber elements each responsive to an electric field component of the wave as it impinges thereon. Each element includes a portion tapered in the direction of wave propagation to provide a relatively wideband response spectrum. Each element includes an output for deriving a voltage replica of the electric field variations intercepted by it. Adjacent elements are positioned relative to each other so that an electric field subsists between adjacent elements in response to the impinging wave. The electric field results in a voltage difference between adjacent elements that is fed to a rectifier to derive dc output power.

  10. High Density Power Converters for Photovoltaic Power Management

    NASA Astrophysics Data System (ADS)

    Sangwan, Rahul

    In typical photovoltaic systems, PV cells are connected in series to achieve high output voltages, which decreases conduction losses and helps the downstream power electronics operate at higher efficiencies. A series connection means that the current through the string is limited by the worst case cell, substring, or module, which can result in suboptimal operation of the rest of the string. Given how even small shading can have a large effect on performance, there has been growing interest in the use of distributed power management architectures to mitigate losses from variation in PV systems. In particular, partial power processing converters have gained traction as a means to improve the performance of PV arrays with small, distributed converters that configure in parallel with PV cells. These converters can use low voltage components, only process a fraction of the total power allowing them to achieve higher efficiencies and power density and also have higher reliability. This work details the design and operation of a partial power processing converter implemented as a Resonant Switched Capacitor (ReSC) converter. An integrated circuit (IC) is designed in 0.18 mum CMOS process. Operation at high frequencies (20-50 MHz) allows high levels of integration with air core inductors directly attached to the die through a gold bump, solder reflow process. Test results for the IC are presented with power density and efficiency metrics. The IC is then used as a partial power processing converter to implement equalization with a specially constructed PV panel. The converter is shown to mitigate power loss due to mismatch.

  11. Wind/water energy converter

    NASA Technical Reports Server (NTRS)

    Paulkovich, J.

    1979-01-01

    Device will convert wind, water, tidal or wave energy into electrical or mechanical energy. Is comprised of windmill-like paddles or blades synchronously geared to orient themselves to wind direction for optimum energy extraction.

  12. Proposed electromagnetic wave energy converter

    NASA Technical Reports Server (NTRS)

    Bailey, R. L.

    1973-01-01

    Device converts wave energy into electric power through array of insulated absorber elements responsive to field of impinging electromagnetic radiation. Device could also serve as solar energy converter that is potentially less expensive and fragile than solar cells, yet substantially more efficient.

  13. Combustor design tool for a gas fired thermophotovoltaic energy converter

    SciTech Connect

    Lindler, K.W.; Harper, M.J.

    1995-07-01

    Recently, there has been a renewed interest in thermophotovoltaic (TPV) energy conversion. A TPV device converts radiant energy from a high temperature incandescent emitter directly into electricity by photovoltaic cells. The current Department of Energy sponsored research involves the design, construction and demonstration of a prototype TPV converter that uses a hydrocarbon fuel (such as natural gas) as the energy source. As the photovoltaic cells are designed to efficiently convert radiant energy at a prescribed wavelength, it is important that the temperature of the emitter be nearly constant over its entire surface. The US Naval Academy has been tasked with the development of a small emitter (with a high emissivity) that can be maintained at 1,756 K (2,700 F). This paper describes the computer spreadsheet model that was developed as a tool to be used for the design of the high temperature emitter.

  14. Combustor design tool for a gas fired thermophotovoltaic energy converter

    SciTech Connect

    Lindler, K.W.; Harper, M.J.

    1995-12-31

    Recently, there has been a renewed interest in thermophotovoltaic (TPV) energy conversion. A TPV device converts radiant energy from a high temperature incandescent emitter directly into electricity by photovoltaic cells. The current Department of Energy sponsored research involves the design, construction and demonstration of a prototype TPV converter that uses a hydrocarbon fuel (such as natural gas) as the energy source. As the photovoltaic cells are designed to efficiently convert radiant energy at a prescribed wavelength, it is important that the temperature of the emitter be nearly constant over its entire surface. The U. S. Naval Academy has been tasked with the development of a small emitter (with a high emissivity) that can be maintained at 1756 K (2700 F). This paper describes the computer spreadsheet model that was developed as a tool to be used for the design of the high temperature emitter.

  15. Photovoltaic and photoelectrochemical conversion of solar energy.

    PubMed

    Grätzel, Michael

    2007-04-15

    The Sun provides approximately 100,000 terawatts to the Earth which is about 10000 times more than the present rate of the world's present energy consumption. Photovoltaic cells are being increasingly used to tap into this huge resource and will play a key role in future sustainable energy systems. So far, solid-state junction devices, usually made of silicon, crystalline or amorphous, and profiting from the experience and material availability resulting from the semiconductor industry, have dominated photovoltaic solar energy converters. These systems have by now attained a mature state serving a rapidly growing market, expected to rise to 300 GW by 2030. However, the cost of photovoltaic electricity production is still too high to be competitive with nuclear or fossil energy. Thin film photovoltaic cells made of CuInSe or CdTe are being increasingly employed along with amorphous silicon. The recently discovered cells based on mesoscopic inorganic or organic semiconductors commonly referred to as 'bulk' junctions due to their three-dimensional structure are very attractive alternatives which offer the prospect of very low cost fabrication. The prototype of this family of devices is the dye-sensitized solar cell (DSC), which accomplishes the optical absorption and the charge separation processes by the association of a sensitizer as light-absorbing material with a wide band gap semiconductor of mesoporous or nanocrystalline morphology. Research is booming also in the area of third generation photovoltaic cells where multi-junction devices and a recent breakthrough concerning multiple carrier generation in quantum dot absorbers offer promising perspectives. PMID:17272237

  16. Ocean tide energy converter

    SciTech Connect

    Rainey, D.E.

    1980-06-24

    A tide motor energy source includes a tidal piston with a valved chamber. The piston drives a hydraulic ram to generate electrical power through a pressure accumulator and hydraulic motor. The ram can be locked hydraulically to enable the tidal piston to be held fixed at a desired elevation and the valves in the chamber permit it to be filled with water or air. The piston with its chamber filled with air at its low tide position and then released for controlled ascent while submerged acts as a submerged float for driving the ram upwardly while the tide runs in during one phase of its operation. The piston with its chamber filled with water while locked at its highest position as the tide begins to run out, and then released to fall under control, acts as a weight suspended in air after the water level drops below the piston for driving the ram downwardly during the second phase of its operation. The rising and falling motion of the tidal piston is used as the energy source.

  17. Photovoltaic energy systems

    NASA Astrophysics Data System (ADS)

    1988-02-01

    An overview is provided of the activities within the National Photovoltaics Program. Tasks conducted by the participating national laboratories or under contract by industrial, academic and other research institutions are highlighted. Activities initiated, renewed, or completed during Fiscal Year 1987 are covered. The listing for each activity provides the task title, objectives, approach, status and accomplishments, milestones, major project reports, the name of the contractor and principal investigator, the directing organization, and the contract funding information. Publications for FY86-87 are also listed.

  18. Limits to Photovoltaic Energy Conversion Efficiency

    NASA Astrophysics Data System (ADS)

    Green, Martin A.

    2015-10-01

    The following sections are included: * Introduction * Photovoltaic converters: essential requirements * Thermodynamic properties of sunlight * `Top-down' thermodynamic efficiency limits * Single-cell efficiency limits * Multiple-junction devices * Other high-efficiency options * Summary * Acknowledgement * References

  19. Large wind energy converter: Growian 3 MW

    NASA Technical Reports Server (NTRS)

    Koerber, F.; Thiele, H. A.

    1979-01-01

    The main features of the Growian wind energy converter are presented. Energy yield, environmental impact, and construction of the energy converter are discussed. Reliability of the windpowered system is assessed.

  20. Enhanced photovoltaic energy conversion using thermally based spectral shaping

    NASA Astrophysics Data System (ADS)

    Bierman, David M.; Lenert, Andrej; Chan, Walker R.; Bhatia, Bikram; Celanović, Ivan; Soljačić, Marin; Wang, Evelyn N.

    2016-06-01

    Solar thermophotovoltaic devices have the potential to enhance the performance of solar energy harvesting by converting broadband sunlight to narrow-band thermal radiation tuned for a photovoltaic cell. A direct comparison of the operation of a photovoltaic with and without a spectral converter is the most critical indicator of the promise of this technology. Here, we demonstrate enhanced device performance through the suppression of 80% of unconvertible photons by pairing a one-dimensional photonic crystal selective emitter with a tandem plasma–interference optical filter. We measured a solar-to-electrical conversion rate of 6.8%, exceeding the performance of the photovoltaic cell alone. The device operates more efficiently while reducing the heat generation rates in the photovoltaic cell by a factor of two at matching output power densities. We determined the theoretical limits, and discuss the implications of surpassing the Shockley–Queisser limit. Improving the performance of an unaltered photovoltaic cell provides an important framework for the design of high-efficiency solar energy converters.

  1. Decentalized solar photovoltaic energy systems

    SciTech Connect

    Krupka, M. C.

    1980-09-01

    Environmental data for decentralized solar photovoltaic systems have been generated in support of the Technology Assessment of Solar Energy Systems program (TASE). Emphasis has been placed upon the selection and use of a model residential photovoltaic system to develop and quantify the necessary data. The model consists of a reference home located in Phoenix, AZ, utilizing a unique solar cell array-roof shingle combination. Silicon solar cells, rated at 13.5% efficiency at 28/sup 0/C and 100 mW/cm/sup 2/ (AMI) insolation are used to generate approx. 10 kW (peak). An all-electric home is considered with lead-acid battery storage, dc-ac inversion and utility backup. The reference home is compared to others in regions of different insolation. Major material requirements, scaled to quad levels of end-use energy include significant quantities of silicon, copper, lead, antimony, sulfuric acid and plastics. Operating residuals generated are negligible with the exception of those from the storage battery due to a short (10-year) lifetime. A brief general discussion of other environmental, health, and safety and resource availability impacts is presented. It is suggested that solar cell materials production and fabrication may have the major environmental impact when comparing all facets of photovoltaic system usage. Fabrication of the various types of solar cell systems involves the need, handling, and transportation of many toxic and hazardous chemicals with attendant health and safety impacts. Increases in production of such materials as lead, antimony, sulfuric acid, copper, plastics, cadmium and gallium will be required should large scale usage of photovoltaic systems be implemented.

  2. DC-DC Converter Topology Assessment for Large Scale Distributed Photovoltaic Plant Architectures

    SciTech Connect

    Agamy, Mohammed S; Harfman-Todorovic, Maja; Elasser, Ahmed; Sabate, Juan A; Steigerwald, Robert L; Jiang, Yan; Essakiappan, Somasundaram

    2011-07-01

    Distributed photovoltaic (PV) plant architectures are emerging as a replacement for the classical central inverter based systems. However, power converters of smaller ratings may have a negative impact on system efficiency, reliability and cost. Therefore, it is necessary to design converters with very high efficiency and simpler topologies in order not to offset the benefits gained by using distributed PV systems. In this paper an evaluation of the selection criteria for dc-dc converters for distributed PV systems is performed; this evaluation includes efficiency, simplicity of design, reliability and cost. Based on this evaluation, recommendations can be made as to which class of converters is best fit for this application.

  3. Photovoltaic Energy Program overview, fiscal year 1997

    SciTech Connect

    1998-02-01

    The US Department of Energy (DOE) Photovoltaic Energy Program fosters the widespread acceptance of photovoltaic (PV) technology and accelerates commercial use of US PV products. The Program is founded on a collaborative strategy involving industry, the research and development community, potential users, utilities, and state and federal agencies. There are three main Program elements: Systems Engineering and Applications, Technology Development, and Research and Development.

  4. Architectures and Control of Submodule Integrated DC-DC Converters for Photovoltaic Applications

    SciTech Connect

    Olalla, C; Clement, D; Rodriguez, M; Maksimovic, D

    2013-06-01

    This paper describes photovoltaic (PV) module architectures with parallel-connected submodule-integrated dc-dc converters (subMICs) that improve efficiency of energy capture in the presence of partial shading or other mismatch conditions. The subMICs are bidirectional isolated dc-dc converters capable of injecting or subtracting currents to balance the module substring voltages. When no mismatches are present, the subMICs are simply shut down, resulting in zero insertion losses. It is shown that the objective of minimum subMIC power processing can be solved as a linear programming problem. A simple close-to-optimal distributed control approach is presented that allows autonomous subMIC control without the need for a central controller or any communication among the subMICs. Furthermore, the proposed control approach is well suited for an isolated-port architecture, which yields additional practical advantages including reduced subMIC power and voltage ratings. The architectures and the control approach are validated by simulations and experimental results using three bidirectional flyback subMICs attached to a standard 180-W, 72-cell PV module, yielding greater than 98% module-level power processing efficiency for a mismatch less than 25%.

  5. Thin film photovoltaic converter and method of preparing same

    SciTech Connect

    Bradley, A.; Felsher, H.; Pollak, F.

    1980-07-29

    A photovoltaic device is described comprising in combination: an electrode comprising a substrate essentially transparent to light; a thin film in intimate contact with said electrode substrate consisting essentially of a a lattice of stacked carbon chains having alternating single and double bonds containing between zero and one hydrogen atom per carbon, degraded from a highly oriented organic polymer, the interface between said film and said electrode substrate constructed to act as a source of photo-induced voltage; wherein said lattice of stacked carbon atoms consists essentially of a conjugated carbon or carbon-hydrogen structure, plus an electron-attracting additive which causes an internal separation of the charges on said stacked carbon atoms by attracting electrons from the pi-bonds of said conjugated carbon structure; and wherein said electron-attracting additive consists essentially of phthalocyanine or one of its metal salts. The method of fabricating a photovoltaic device which comprises the steps of: depositing a film of highly oriented organic polymer on a transparent electrically-conducting substrate; subjecting said film in situ to controlled degradation by chemical, thermal or radiation treatment to form a condensed aromatic or otherwise highly conjugated carbon macromolecule system with a high population of mobile pi-electrons; wherein the step of subjecting said film in situ to controlled degradation is carried out in the presence of an electronattracting compound, to form chains of indefinite length by charge transfer complexed with the condensed aromatic or highly conjugated carbon macromolecule system; and wherein said electron-attracting compound is a metallic salt of phthalocyanine formed in situ by thermal reaction of an inorganic salt and in nitrogen-containing derivative.

  6. Ocean floor mounting of wave energy converters

    SciTech Connect

    Siegel, Stefan G

    2015-01-20

    A system for mounting a set of wave energy converters in the ocean includes a pole attached to a floor of an ocean and a slider mounted on the pole in a manner that permits the slider to move vertically along the pole and rotate about the pole. The wave energy converters can then be mounted on the slider to allow adjustment of the depth and orientation of the wave energy converters.

  7. Controller for a wave energy converter

    SciTech Connect

    Wilson, David G.; Bull, Diana L.; Robinett, III, Rush D.

    2015-09-22

    A wave energy converter (WEC) is described, the WEC including a power take off (PTO) that converts relative motion of bodies of the WEC into electrical energy. A controller controls operation of the PTO, causing the PTO to act as a motor to widen a wave frequency spectrum that is usable to generate electrical energy.

  8. Improvement of photovoltaic pumping systems based on standard frequency converters by means of programmable logic controllers

    SciTech Connect

    Fernandez-Ramos, Jose; Narvarte-Fernandez, Luis; Poza-Saura, Fernando

    2010-01-15

    Photovoltaic pumping systems (PVPS) based on standard frequency converters (SFCs) are currently experiencing a growing interest in pumping programmes implemented in remote areas because of their high performance in terms of component reliability, low cost, high power range and good availability of components virtually anywhere in the world. However, in practical applications there have appeared a number of problems related to the adaptation of the SFCs to the requirements of the photovoltaic pumping systems (PVPS). Another disadvantage of dedicated PVPS is the difficulty in implementing maximum power point tracking (MPPT). This paper shows that these problems can be solved through the addition of a basic industrial programmable logic controller (PLC) to the system. This PLC does not increase the cost and complexity of the system, but improves the adaptation of the SFC to the photovoltaic pumping system, and increases the overall performance of the system. (author)

  9. Photovoltaic power converter system with a controller configured to actively compensate load harmonics

    DOEpatents

    de Rooij, Michael Andrew; Steigerwald, Robert Louis; Delgado, Eladio Clemente

    2008-12-16

    Photovoltaic power converter system including a controller configured to reduce load harmonics is provided. The system comprises a photovoltaic array and an inverter electrically coupled to the array to generate an output current for energizing a load connected to the inverter and to a mains grid supply voltage. The system further comprises a controller including a first circuit coupled to receive a load current to measure a harmonic current in the load current. The controller includes a second circuit to generate a fundamental reference drawn by the load. The controller further includes a third circuit for combining the measured harmonic current and the fundamental reference to generate a command output signal for generating the output current for energizing the load connected to the inverter. The photovoltaic system may be configured to compensate harmonic currents that may be drawn by the load.

  10. Radiant energy to electric energy converter

    NASA Technical Reports Server (NTRS)

    Sher, Arden (Inventor)

    1980-01-01

    Radiant energy is converted into electric energy by irradiating a capacitor including an ionic dielectric. The dielectric is a sintered crystal superionic conductor, e.g., lanthanum trifluoride, lanthanum trichloride, or silver bromide, so that a multiplicity of crystallites exist between electrodes of the capacitor. The radiant energy cyclically irradiates the dielectric so that the dielectric exhibits a cyclic photocapacitive like effect. Adjacent crystallites have abutting surfaces that enable the crystallites to effectively form a multiplicity of series capacitor elements between the electrodes. Each of the capacitor elements has a dipole layer only on or near its surface. The capacitor is initially charged to a voltage just below the dielectric breakdown voltage by connecting it across a DC source causing a current to flow through a charging resistor to the dielectric. The device can be utilized as a radiant energy detector or as a solar energy cell.

  11. NASA-OAST photovoltaic energy conversion program

    NASA Technical Reports Server (NTRS)

    Mullin, J. P.; Loria, J. C.

    1984-01-01

    The NASA program in photovoltaic energy conversion research is discussed. Solar cells, solar arrays, gallium arsenides, space station and spacecraft power supplies, and state of the art devices are discussed.

  12. Converting solar-photovoltaic power into exportable products

    SciTech Connect

    Oman, H.

    1997-12-31

    Nations, states, and even communities must generate exportable products that earn money for buying needed imports. Exports have ranged from tourist services to hardwood logs. Fertile land, with irrigation water and fertilizer, grows exportable food. On the other hand a hot dry desert with no mineral resources presents a challenge to its occupants. Solar power could be generated and exported, but that requires construction of expensive transmission lines which are in service only when the sun shines. Among new options is a solar-powered plant that recovers zinc from the zinc oxide produced during discharge of zinc-air electric-vehicle batteries. A hectare-size solar-power plant with 30-percent efficient solar cells can in eight hours recover enough zinc to power 36,000 /km (22,000 miles) of travel in lightweight 4-passenger electric vehicles. A by-product could be renewable fuel for use by local residents in electric bicycles. One oriented solar panel, 10 meters by 10 meters in size, with 30-percent efficient solar cells, could in one day deliver enough energy for traveling 14,700 km (9176 miles) on bicycles. This by far exceeds the travel distance that could be obtained in one day by riding on an animal that is pastured on a s0-by-10 meter area.

  13. Amorphous silicon photovoltaic devices

    SciTech Connect

    Carlson, David E.; Lin, Guang H.; Ganguly, Gautam

    2004-08-31

    This invention is a photovoltaic device comprising an intrinsic or i-layer of amorphous silicon and where the photovoltaic device is more efficient at converting light energy to electric energy at high operating temperatures than at low operating temperatures. The photovoltaic devices of this invention are suitable for use in high temperature operating environments.

  14. Photovoltaics

    NASA Astrophysics Data System (ADS)

    Seippel, R. G.

    This book attempts to provide the reader with a cursory look at solar energy from a quarry of quartz to a sophisticated solar system. The progression of the theories of light is discussed along with the progression of photoelectricity, light rays, the optical spectrum, light reception, photodetection, aspects of photometry and radiometry, preferred terms in radiometric measurement, semiconductor physics, and light energy availability. Other subjects explored are related to manufacturing processes, photovoltaic materials, crystal growing, slicing techniques, wafer finishing, solar cell fabrication, photovoltaic cell types, concentrators, module fabrication, problems of quality assurance, photovoltaic systems, and the photovoltaics hierarchy. Attention is given to the polycrystalline cell, insulator cells, cadmium sulfide cells, amorphous silicon cells, an electrochemical cell, and the low-cost solar array project.

  15. Space satellite power system. [conversion of solar energy by photovoltaic solar cell arrays

    NASA Technical Reports Server (NTRS)

    Glaser, P. E.

    1974-01-01

    The concept of a satellite solar power station was studied. It is shown that it offers the potential to meet a significant portion of future energy needs, is pollution free, and is sparing of irreplaceable earth resources. Solar energy is converted by photovoltaic solar cell arrays to dc energy which in turn is converted into microwave energy in a large active phased array. The microwave energy is beamed to earth with little attenuation and is converted back to dc energy on the earth. Economic factors are considered.

  16. Boost matrix converters in clean energy systems

    NASA Astrophysics Data System (ADS)

    Karaman, Ekrem

    This dissertation describes an investigation of novel power electronic converters, based on the ultra-sparse matrix topology and characterized by the minimum number of semiconductor switches. The Z-source, Quasi Z-source, Series Z-source and Switched-inductor Z-source networks were originally proposed for boosting the output voltage of power electronic inverters. These ideas were extended here on three-phase to three-phase and three-phase to single-phase indirect matrix converters. For the three-phase to three-phase matrix converters, the Z-source networks are placed between the three-switch input rectifier stage and the output six-switch inverter stage. A brief shoot-through state produces the voltage boost. An optimal pulse width modulation technique was developed to achieve high boosting capability and minimum switching losses in the converter. For the three-phase to single-phase matrix converters, those networks are placed similarly. For control purposes, a new modulation technique has been developed. As an example application, the proposed converters constitute a viable alternative to the existing solutions in residential wind-energy systems, where a low-voltage variable-speed generator feeds power to the higher-voltage fixed-frequency grid. Comprehensive analytical derivations and simulation results were carried out to investigate the operation of the proposed converters. Performance of the proposed converters was then compared between each other as well as with conventional converters. The operation of the converters was experimentally validated using a laboratory prototype.

  17. High Step-Up DC—DC Converter for AC Photovoltaic Module with MPPT Control

    NASA Astrophysics Data System (ADS)

    Sundar, Govindasamy; Karthick, Narashiman; Rama Reddy, Sasi

    2014-08-01

    This paper presents the high gain step-up BOOST converter which is essential to step up the low output voltage from PV panel to the high voltage according to the requirement of the application. In this paper a high gain BOOST converter with coupled inductor technique is proposed with the MPPT control. Without extreme duty ratios and the numerous turns-ratios of a coupled inductor this converter achieves a high step-up voltage-conversion ratio and the leakage energy of the coupled inductor is efficiently recycled to the load. MPPT control used to extract the maximum power from PV panel by controlling the Duty ratio of the converter. The PV panel, BOOST converter and the MPPT are modeled using Sim Power System blocks in MATLAB/SIMULINK environment. The prototype model of the proposed converter has been implemented with the maximum measured efficiency is up to 95.4% and full-load efficiency is 93.1%.

  18. Hydrodynamic Performance of a Wave Energy Converter

    NASA Astrophysics Data System (ADS)

    Yang, Yingchen

    2010-11-01

    To harvest energy from ocean waves, a new wave energy converter (WEC) was proposed and tested in a wave tank. The WEC freely floats on the water surface and rides waves. It utilizes its wave-driven angular oscillation to convert the mechanical energy of waves into electricity. To gain the maximum possible angular oscillation of the WEC under specified wave conditions, both floatation of the WEC and wave interaction with the WEC play critical roles in a joint fashion. During the experiments, the submersion condition of the WEC and wave condition were varied. The results were analyzed in terms of the oscillation amplitude, stability, auto-orientation capability, and wave frequency dependency.

  19. Solar energy converter using surface plasma waves

    NASA Technical Reports Server (NTRS)

    Anderson, L. M. (Inventor)

    1984-01-01

    Sunlight is dispersed over a diffraction grating formed on the surface of a conducting film on a substrate. The angular dispersion controls the effective grating period so that a matching spectrum of surface plasmons is excited for parallel processing on the conducting film. The resulting surface plasmons carry energy to an array of inelastic tunnel diodes. This solar energy converter does not require different materials for each frequency band, and sunlight is directly converted to electricity in an efficient manner by extracting more energy from the more energetic photons.

  20. WEC-Sim (Wave Energy Converter - SIMulator)

    Energy Science and Technology Software Center (ESTSC)

    2014-11-26

    WEC-Sim (Wave Energy Converter SIMulator) is a code developed by Sandia National Laboratories and the National Renewable Energy Laboratory to model wave energy converters (WECs) when they are subject to operational waves. The code is a time-domain modeling tool developed in MATLAB/Simulink using the multi-body dynamics solver SimMechanics. In WEC-Sim, WECs are modeled by connecting rigid bodies to one another with joint or constraint blocks from the WEC-Sim library. WEC-Sim is a publicly available, open-sourcemore » code to model WECs.« less

  1. WEC-Sim (Wave Energy Converter - SIMulator)

    SciTech Connect

    2014-11-26

    WEC-Sim (Wave Energy Converter SIMulator) is a code developed by Sandia National Laboratories and the National Renewable Energy Laboratory to model wave energy converters (WECs) when they are subject to operational waves. The code is a time-domain modeling tool developed in MATLAB/Simulink using the multi-body dynamics solver SimMechanics. In WEC-Sim, WECs are modeled by connecting rigid bodies to one another with joint or constraint blocks from the WEC-Sim library. WEC-Sim is a publicly available, open-source code to model WECs.

  2. Trimode Power Converter optimizes PV, diesel and battery energy sources

    SciTech Connect

    O`Sullivan, G.; Bonn, R.; Bower, W.

    1994-07-01

    Conservatively, there are 100,000 localities in the world waiting for the benefits that electricity can provide, and many of these are in climates where sunshine is plentiful. With these locations in mind a prototype 30 kW hybrid system has been assembled at Sandia to prove the reliability and economics of photovoltaic, diesel and battery energy sources managed by an autonomous power converter. In the Trimode Power Converter the same power parts, four IGBT`s with an isolation transformer and filter components, serve as rectifier and charger to charge the battery from the diesel; as a stand-alone inverter to convert PV and battery energy to AC; and, as a parallel inverter with the diesel-generator to accommodate loads larger than the rating of the diesel. Whenever the diesel is supplying the load, an algorithm assures that the diesel is running at maximum efficiency by regulating the battery charger operating point. Given the profile of anticipated solar energy, the cost of transporting diesel fuel to a remote location and a five year projection of load demand, a method to size the PV array, battery and diesel for least cost is developed.

  3. Design and optimization of GaAs photovoltaic converter for laser power beaming

    NASA Astrophysics Data System (ADS)

    Shan, Tiqiang; Qi, Xinglin

    2015-07-01

    GaAs photovoltaic (PV) converters are useful for the conversion of monochromatic light into electrical power in numerous military and industrial applications. The work of this paper is to design a monochromatic GaAs PV converter for coupling to laser beams in the wavelength of 790-840 nm and optimize its structure, layer thicknesses, doping levels of the emitter and base, and antireflection coating. Modeling calculations of the GaAs PV converter optimization are carried out using PC-1D. From the highest efficiency point of view, the best wavelength is 840 nm at which the optimized structure gives an efficiency of 61.8% theoretically. Experiment results under 808 nm laser power beaming show that high optical-to-electrical conversion efficiency of 53.23% at 5 W/cm2 is achieved using the optimized GaAs PV laser converter. Finally, accurate extraction of the key parameters, viz. the ideality factor, reverse saturation current, series resistance and shunt resistance is introduced. Variations of these parameters with illumination intensity are also investigated analytically based on the one diode model, which are necessary for the design of a high performance PV generation system.

  4. Photovoltaic energy program overview: Fiscal year 1994

    SciTech Connect

    1995-03-01

    This is the 1994 overview for the Photovoltaic Energy Program. The topics of this overview include cooperative research projects to improve PV systems and develop pre-commercial prototypes of new PV products, expanding understanding of the fundamental mechanisms governing the formation and performance of PV materials, and helping US industry enhance its leadership position in the PV market.

  5. Ocean wave energy converting vessel

    SciTech Connect

    Boyce, P.F.

    1986-08-26

    An ocean wave energy conversion system is described comprised of a four beam quadrapod supported by bouyant members from which is suspended a pendulum. The pendulum contains a vertical generator shaft and a generator, the generator shaft being splined and fitted with two racheted pulleys, the pulleys being looped, one clockwise and one counterclockwise with separate cables. The cables are attached at their ends to the bow and stern of the quadrapod, whereby the generator shaft will pin when the quadrapod rocks over waves and the pendulum tends toward the center of earth.

  6. Solar energy recorder. [for converter site selection

    NASA Technical Reports Server (NTRS)

    Lollar, R. B.; Mandt, R. R.

    1974-01-01

    A serious obstacle to the large-scale terrestrial application of solar energy lies in the scarcity of reliable data on the amount of solar energy at candidate converter sites. This paper describes a system designed to monitor and record, automatically, the values of the direct and total (sun and sky) solar radiation which would be seen by either tracking or fixed-type solar converters. A further pressing need addressed by the system is the means for efficiency testing and evaluation of solar cells, solar collectors and solar concentrator systems, under outdoor exposure to natural sunlight and weather conditions for extended periods. The design was accomplished in support of the Marshall Space Flight Center, NASA, where design concepts and materials for large-scale terrestrial solar energy converters are currently being evaluated.

  7. PHOTOVOLTAIC ENERGY SYSTEMS: ENVIRONMENTAL CONCERNS AND CONTROL TECHNOLOGY NEEDS

    EPA Science Inventory

    Technical and commercial readiness for alternate photovoltaic energy systems, and waste streams from three different photovoltaic systems are examined. This analysis suggests that some uncontrolled waste streams could be declared toxic or hazardous under various provisions of the...

  8. A Standalone Solar Photovoltaic Power Generation using Cuk Converter and Single Phase Inverter

    NASA Astrophysics Data System (ADS)

    Verma, A. K.; Singh, B.; Kaushika, S. C.

    2013-03-01

    In this paper, a standalone solar photovoltaic (SPV) power generating system is designed and modeled using a Cuk dc-dc converter and a single phase voltage source inverter (VSI). In this system, a dc-dc boost converter boosts a low voltage of a PV array to charge a battery at 24 V using a maximum power point tracking control algorithm. To step up a 24 V battery voltage to 360 V dc, a high frequency transformer based isolated dc-dc Cuk converter is used to reduce size, weight and losses. The dc voltage of 360 V is fed to a single phase VSI with unipolar switching to achieve a 230 Vrms, 50 Hz ac. The main objectives of this investigation are on efficiency improvement, reduction in cost, weight and size of the system and to provide an uninterruptible power to remotely located consumers. The complete SPV system is designed and it is modeled in MATLAB/Simulink. The simulated results are presented to demonstrate its satisfactory performance for validating the proposed design and control algorithm.

  9. Investigation of potential islanding problems of a line-commutated static power converter in photovoltaic systems

    SciTech Connect

    Sims, T.R.; Jones, R.A. . Research and Development Dept.); Imece, A.F. )

    1990-09-01

    Islanding is one of the major concerns that electric power utilities have about the impact of distributed photovoltaic (PV) generation. Islanding is the isolated operation of PV systems after the interruption of utility power. This paper reports the results of a research project on the possible islanding operation of a section of a distribution feeder containing line-commutated static power converters. The approach of the project was to develop a computer model of the SPC to predict islanding operation and verify the model with laboratory and field tests. The computer model accurately predicted the operation of the SPC during islanding. Furthermore, the effect of general system parameters on the islanding performance of the Gemini line-commutated SPC are presented.

  10. Photovoltaic power - An important new energy option

    NASA Technical Reports Server (NTRS)

    Ferber, R. R.

    1983-01-01

    A review of photovoltaic (PV) power technology is presented with an emphasis of PV as an economical and technically feasible alternative source of energy. The successful completion of the development and transfer of emerging low-cost technologies into a fully commercialized status are identified as the means to the realization of this option's full potential. The DOE National Photovoltaics Program, a significant sponsor of PV R&D, expects both flat-plate and concentrator collectors to meet established cost targets. Citing the DOE large flat-plate grid-connected system project of the Sacramento Municipal Utility District, current technology modules priced at near $5/Wp (1983 dollars) are steadily reducing costs. A recent DOE study suggests that PV-generated electricity produced at a 30-year levelized cost of 15 cents per kWh would represent a viable energy supply alternative for the nation.

  11. Wind energy converter utilizing vortex augmentation

    SciTech Connect

    Edwards, S. S.

    1985-05-14

    A wind energy conversion apparatus is disclosed herein for converting the linear momentum of wind energy into a pair of concentrated, counter-rotating and side-by-side regions of high angular momentum which includes a wing having variable angle of attack positionable forward of the entrance to an elongated duct having a bell mouth including an upper, inner reflex angular surface leading into a bifurcated duct section terminating in a diffuser augmenter at the aft facing area of the duct and which includes propellors operable to extract energy from the angular momentum in the established regions for driving electric generators or generator therefrom.

  12. Efficient Power Converters for PV Arrays : Scalable Submodule Power Conversion for Utility-Scale Photovoltaics

    SciTech Connect

    2012-02-23

    Solar ADEPT Project: SolarBridge is developing a new power conversion technique to improve the energy output of PV power plants. This new technique is specifically aimed at large plants where many solar panels are connected together. SolarBridge is correcting for the inefficiencies that occur when two solar panels that encounter different amounts of sun are connected together. In most conventional PV system, the weakest panel limits the energy production of the entire system. That’s because all of the energy collected by the PV system feeds into a single collection point where a central inverter then converts it into useable energy for the grid. SolarBridge has found a more efficient and cost-effective way to convert solar energy, correcting these power differences before they reach the grid.

  13. Silicon nanowires for photovoltaic solar energy conversion.

    PubMed

    Peng, Kui-Qing; Lee, Shuit-Tong

    2011-01-11

    Semiconductor nanowires are attracting intense interest as a promising material for solar energy conversion for the new-generation photovoltaic (PV) technology. In particular, silicon nanowires (SiNWs) are under active investigation for PV applications because they offer novel approaches for solar-to-electric energy conversion leading to high-efficiency devices via simple manufacturing. This article reviews the recent developments in the utilization of SiNWs for PV applications, the relationship between SiNW-based PV device structure and performance, and the challenges to obtaining high-performance cost-effective solar cells. PMID:20931630

  14. Siemens and siemens-like processes for producing photovoltaics: Energy payback time and lifetime carbon emissions

    NASA Astrophysics Data System (ADS)

    Jiao, Yubo; Salce, Alex; Ben, Wade; Jiang, Feng; Ji, Xiaoyang; Morey, Evan; Lynch, David

    2011-01-01

    Polysilicon photovoltaics will play a significant role in meeting the world's shortfall in electrical energy this century. The photovoltaic industry relies on high-purity silicon produced in the Siemens process. New Siemens-like processes (which convert metallurgical silicon to trichlorosilane and deposit purified silicon through the decomposition of silane) and metallurgical processes for producing solar silicon are under development. Their energy payback time and lifetime carbon emissions are reviewed. The history of development of Siemens and Siemens-like processes is summarized.

  15. Clustering of cycloidal wave energy converters

    DOEpatents

    Siegel, Stefan G.

    2016-03-29

    A wave energy conversion system uses a pair of wave energy converters (WECs) on respective active mountings on a floating platform, so that the separation of the WECs from each other or from a central WEC can be actively adjusted according to the wavelength of incident waves. The adjustable separation facilitates operation of the system to cancel reactive forces, which may be generated during wave energy conversion. Modules on which such pairs of WECs are mounted can be assembled with one or more central WECs to form large clusters in which reactive forces and torques can be made to cancel. WECs of different sizes can be employed to facilitate cancelation of reactive forces and torques.

  16. Energy utilization in fluctuating biological energy converters

    PubMed Central

    Szőke, Abraham; Hajdu, Janos

    2016-01-01

    We have argued previously [Szoke et al., FEBS Lett. 553, 18–20 (2003); Curr. Chem. Biol. 1, 53–57 (2007)] that energy utilization and evolution are emergent properties based on a small number of established laws of physics and chemistry. The relevant laws constitute a framework for biology on a level intermediate between quantum chemistry and cell biology. There are legitimate questions whether these concepts are valid at the mesoscopic level. Such systems fluctuate appreciably, so it is not clear what their efficiency is. Advances in fluctuation theorems allow the description of such systems on a molecular level. We attempt to clarify this topic and bridge the biochemical and physical descriptions of mesoscopic systems. PMID:27191009

  17. Mechanical vibration to electrical energy converter

    DOEpatents

    Kellogg, Rick Allen; Brotz, Jay Kristoffer

    2009-03-03

    Electromechanical devices that generate an electrical signal in response to an external source of mechanical vibrations can operate as a sensor of vibrations and as an energy harvester for converting mechanical vibration to electrical energy. The devices incorporate a magnet that is movable through a gap in a ferromagnetic circuit, wherein a coil is wound around a portion of the ferromagnetic circuit. A flexible coupling is used to attach the magnet to a frame for providing alignment of the magnet as it moves or oscillates through the gap in the ferromagnetic circuit. The motion of the magnet can be constrained to occur within a substantially linear range of magnetostatic force that develops due to the motion of the magnet. The devices can have ferromagnetic circuits with multiple arms, an array of magnets having alternating polarity and, encompass micro-electromechanical (MEM) devices.

  18. Image processing to optimize wave energy converters

    NASA Astrophysics Data System (ADS)

    Bailey, Kyle Marc-Anthony

    The world is turning to renewable energies as a means of ensuring the planet's future and well-being. There have been a few attempts in the past to utilize wave power as a means of generating electricity through the use of Wave Energy Converters (WEC), but only recently are they becoming a focal point in the renewable energy field. Over the past few years there has been a global drive to advance the efficiency of WEC. Placing a mechanical device either onshore or offshore that captures the energy within ocean surface waves to drive a mechanical device is how wave power is produced. This paper seeks to provide a novel and innovative way to estimate ocean wave frequency through the use of image processing. This will be achieved by applying a complex modulated lapped orthogonal transform filter bank to satellite images of ocean waves. The complex modulated lapped orthogonal transform filterbank provides an equal subband decomposition of the Nyquist bounded discrete time Fourier Transform spectrum. The maximum energy of the 2D complex modulated lapped transform subband is used to determine the horizontal and vertical frequency, which subsequently can be used to determine the wave frequency in the direction of the WEC by a simple trigonometric scaling. The robustness of the proposed method is provided by the applications to simulated and real satellite images where the frequency is known.

  19. Investigations of DC power supplies with optoelectronic transducers and RF energy converters

    NASA Astrophysics Data System (ADS)

    Guzowski, B.; Gozdur, R.; Bernacki, L.; Lakomski, M.

    2016-04-01

    Fiber Distribution Cabinets (FDC) monitoring systems are increasingly popular. However it is difficult to realize such system in passive FDC, due to lack of source of power supply. In this paper investigation of four different DC power supplies with optoelectronic transducers is described. Two converters: photovoltaic power converter and PIN photodiode can convert the light transmitted through the optical fiber to electric energy. Solar cell and antenna RF-PCB are also tested. Results presented in this paper clearly demonstrate that it is possible to build monitoring system in passive FDC. During the tests maximum obtained output power was 11 mW. However all converters provided enough power to excite 32-bit microcontroller with ARM-cores and digital thermometer.

  20. Fluid energy converting method and apparatus

    SciTech Connect

    Arnold, L.

    1980-01-22

    A method and apparatus are disclosed for converting the kinetic energy of a moving fluid stream into useful work by means of a cascade of thin airfoils positioned therein. In one embodiment, the airfoils are provided with at least two degrees of freedom and adjacent airfoils are movable out of phase. The airfoils are subjected to the aerodynamically induced oscillations caused by the aeroelastic phenomenon known as flutter and the oscillatory movement is then harnessed to do useful work. In an alternate embodiment, a cascade of airfoils is mechanically oscillated within a moving fluid stream to increase the propulsion of the fluid. Where the fluid is a liquid, the cascade includes a plurality of hydrofoils.

  1. Fluid energy converting method and apparatus

    SciTech Connect

    Arnold, L.

    1982-08-31

    There is disclosed a method and apparatus for converting the kinetic energy of a moving fluid stream into useful work by means of a cascade of thin airfoils positioned therein. In one embodiment, the airfoils are provided with at least two degrees of freedom and adjacent airfoils are movable out of phase. The airfoils are subjected to the aerodynamically induced oscillations caused by the aeroelastic phenomenon known as flutter and the oscillatory movement is then harnessed to do useful work. In an alternate embodiment, a cascade of airfoils is mechanically oscillated within a moving fluid stream to increase the propulsion of the fluid. Where the fluid is a liquid, the cascade includes a plurality of hydrofoils.

  2. Converting sensitive waste into cleaner energy

    SciTech Connect

    Schriner, D.; Skinner, R.

    1997-10-01

    The destruction of sensitive unclassified information (SUI) has always been expensive due to the need for special controls to ensure its protection from disclosure to unauthorized persons. The sensitive documents were shredded, buried at the landfill, or sent to a recycling company. The Department of Energy (DOE) Idaho National Engineering and Environmental Laboratory (INEEL), operated by Lockheed Martin Idaho Technologies Company (LMITCO), has created an innovative method to dispose of its sensitive unclassified paper waste which has security, economic, and environmental benefits. A new cubing facility at the INEEL converts office and industrial waste into compact cubes which are then combined with coal and burned as a source of heat and process steam to run the Idaho Chemical Processing Plant (ICPP) facility. The process-engineered fuel, consisting of 25% cubes and 75% coal, bums cleaner than coal with lower emissions of sulfur dioxide and nitrogen oxides. The alternative fuel also reduces fuel costs, eliminates paying a recycling company, reduces the expense of landfill disposal, increases the life of the landfill, and provides energy to operate a large facility. The Operations Security (OPSEC) team capitalized on this waste to energy technology by recommending that the large quantities of sensitive information (documents) generated at the INEEL be disposed of in this manner. In addition to the economic and environmental benefits, this disposal method minimizes the vulnerabilities of SUI from disclosure to unauthorized personnel. The {open_quotes}cuber{close_quotes} technology has potential application in government and industry for protection of SUI.

  3. NASA-OAST program in photovoltaic energy conversion

    NASA Technical Reports Server (NTRS)

    Mullin, J. P.; Flood, D. J.

    1982-01-01

    The NASA program in photovoltaic energy conversion includes research and technology development efforts on solar cells, blankets, and arrays. The overall objectives are to increase conversion efficiency, reduce mass, reduce cost, and increase operating life. The potential growth of space power requirements in the future presents a major challenge to the current state of technology in space photovoltaic systems.

  4. Photovoltaics as a terrestrial energy source. Volume 3: An overview

    NASA Technical Reports Server (NTRS)

    Smith, J. L.

    1980-01-01

    Photovoltaic (PV) systems were evaluated in terms of their potential for terrestrial application A comprehensive overview of important issues which bear on photovoltaic (PV) systems development is presented. Studies of PV system costs, the societal implications of PV system development, and strategies in PV research and development in relationship to current energy policies are summarized.

  5. Photovoltaic Energy Program Overview Fiscal Year 1996

    SciTech Connect

    1997-05-01

    Significant activities in the National Photovoltaic Program are reported for each of the three main program elements. In Research and Development, advances in thin-film materials and crystalline silicon materials are described. The Technology Development report describes activities in photovoltaic manufacturing technology, industrial expansion, module and array development, and testing photovoltaic system components. Systems Engineering and Applications projects described include projects with government agencies, projects with utilities, documentation of performance for international applications, and product certification.

  6. Fabrication of photovoltaic laser energy converterby MBE

    NASA Technical Reports Server (NTRS)

    Lu, Hamilton; Wang, Scott; Chan, W. S.

    1993-01-01

    A laser-energy converter, fabricated by molecular beam epitaxy (MBE), was developed. This converter is a stack of vertical p-n junctions connected in series by low-resistivity, lattice matched CoSi2 layers to achieve a high conversion efficiency. Special high-temperature electron-beam (e-beam) sources were developed especially for the MBE growth of the junctions and CoSi2 layers. Making use of the small (greater than 1.2 percent) lattice mismatch between CoSi2 and Si layers, high-quality and pinhole-free epilayers were achieved, providing a capability of fabricating all the junctions and connecting layers as a single growth process with one pumpdown. Well-defined multiple p-n junctions connected by CoSi2 layers were accomplished by employing a low growth temperature (greater than 700 C) and a low growth rate (less than 0.5 microns/hour). Producing negligible interdiffusion, the low growth temperature and rate also produced negligible pinholes in the CoSi2 layers. For the first time, a stack of three p-n junctions connected by two 10(exp -5) Ohm-cm CoSi2 layers was achieved, meeting the high conversion efficiency requirement. This process can now be optimized for high growth rate to form a practical converter with 10 p-n junctions in the stack.

  7. Photovoltaics

    SciTech Connect

    Deb, S.K.

    1985-01-01

    Photovoltaics, the direct conversion of sunlight into electrical energy, may be the best hope for a relatively clean, secure, and inexhaustible source of energy for the future. To stimulate the growth of this technology as a viable energy supply option, considerable research and development has been directed, in both the private and public sectors, to a variety of materials and devices. The technology has sufficiently matured in recent years to be seriously considered as an alternative to conventional energy sources. Despite phenomenal advances in energy conversion efficiencies, many problems still remain to be solved. It is timely, therefore, to review various technological options available. This review critically assesses the status and promise of this emerging technology by a group of experts, each of whom has presented an extended invited paper on his specific field of expertise. This collection of presentations is intended to be an authoritative review of the technology including its developments, current status, and projections for future direction. The content of this review was carefully chosen to represent most of the leading state-of-the-art technologies; these are divided into four areas: (i) a general overview and discussion of silicon technology; (ii) high efficiency multijunction solar cells; (iii) amorphous silicon solar cells; and (iv) thin film compound semiconductors.

  8. Energy converting material for solar cell application

    NASA Astrophysics Data System (ADS)

    Pokhrel, Madhab; Kumar, G. A.; Sardar, Dhiraj K.

    2012-02-01

    In this paper, we discuss the concept of an efficient infrared upconverting phosphor as an energy converting material that could potentially improve the efficiency of Si solar cells in bifacial configuration. Basic spectroscopic studies of Yb and Er-doped La2O2S phosphor was reported with particular attention to its upconversion properties under 1550 nm excitation. Different concentrations of phosphors were synthesized by solid state flux fusion method. The phosphor powders were well crystallized in a hexagonal shape with an average size 300-400 nm. The most efficient upconverting sample (1%Yb: 9% Er doped La2O2S) was also studied under the illumination with infrared (IR) broad band spectrum above 1000 nm. Our measurements show that even with an excitation power density of 0.159 W/cm2 using a tungsten halogen lamp the material shows efficient upconversion corroborating the fact that the present phosphors could be potential candidates for improving the efficiency of the present Si solar cells.

  9. 78 FR 40132 - Wave Energy Converter Prize Administration Webinar

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-03

    ... of Energy Efficiency and Renewable Energy Wave Energy Converter Prize Administration Webinar AGENCY: Office of Energy Efficiency and Renewable Energy (EERE), U.S. Department of Energy (DOE). ACTION: Notice... available for public review on the DOE Office of Energy Efficiency and Renewable Energy (EERE) Web site...

  10. Enhanced Reliability of Photovoltaic Systems with Energy Storage and Controls

    SciTech Connect

    Manz, D.; Schelenz, O.; Chandra, R.; Bose, S.; de Rooij, M.; Bebic, J.

    2008-02-01

    This report summarizes efforts to reconfigure loads during outages to allow individual customers the opportunity to enhance the reliability of their electric service through the management of their loads, photovoltaics, and energy storage devices.

  11. Photovoltaic energy systems: Program summary fiscal year 1983

    NASA Technical Reports Server (NTRS)

    1984-01-01

    An overview of government funded activities in photovoltaic energy conversion research is given. Introductory information, a list of directing organizations, a list of acronyms and abbreviations, and an index of current contractors are given.

  12. Renewable Energy, Photovoltaic Systems Near Airfields. Electromagnetic Interference

    SciTech Connect

    Deline, Chris; Dann, Geoff

    2015-04-01

    Recent increases in photovoltaic (PV) systems on Department of the Navy (DON) land and potential siting near airfields prompted Commander, Naval Installations Command to fund the Naval Facilities Engineering Command to evaluate the impact of electromagnetic interference (EMI) from PV systems on airfield electronic equipment. Naval Facilities Engineering and Expeditionary Warfare Center tasked Department of Energy National Renewable Energy laboratory (NREL) to conduct the assessment. PV systems often include high-speed switching semiconductor circuits to convert the voltage produced by the PV arrays to the voltage needed by the end user. Switching circuits inherently produce electromagnetic radiation at harmonics of the switching frequency. In this report, existing literature is summarized and tests to measure emissions and mitigation methods are discussed. The literature shows that the emissions from typical PV systems are low strength and unlikely to cause interference to most airfield electronic systems. With diligent procurement and siting of PV systems, including specifications for FCC Part 15 Class A compliant equipment and a 250-foot setback from communication equipment, NREL anticipates little to no EMI impact on nearby communications or telemetry equipment.

  13. Optimisation Of a Magnetostrictive Wave Energy Converter

    NASA Astrophysics Data System (ADS)

    Mundon, T. R.; Nair, B.

    2014-12-01

    Oscilla Power, Inc. (OPI) is developing a patented magnetostrictive wave energy converter aimed at reducing the cost of grid-scale electricity from ocean waves. Designed to operate cost-effectively across a wide range of wave conditions, this will be the first use of reverse magnetostriction for large-scale energy production. The device architecture is a straightforward two-body, point absorbing system that has been studied at length by various researchers. A large surface float is anchored to a submerged heave (reaction) plate by multiple taut tethers that are largely made up of discrete, robust power takeoff modules that house the magnetostrictive generators. The unique generators developed by OPI utilize the phenomenon of reverse magnetostriction, which through the application of load to a specific low cost alloy, can generate significant magnetic flux changes, and thus create power through electromagnetic induction. Unlike traditional generators, the mode of operation is low-displacement, high-force, high damping which in combination with the specific multi-tether configuration creates some unique effects and interesting optimization challenges. Using an empirical approach with a combination of numerical tools, such as ORCAFLEX, and physical models, we investigated the properties and sensitivities of this system arrangement, including various heave plate geometries, with the overall goal of identifying the mass and hydrodynamic parameters required for optimum performance. Furthermore, through a detailed physical model test program at the University of New Hampshire, we were able to study in more detail how the heave plate geometry affects the drag and added mass coefficients. In presenting this work we will discuss how alternate geometries could be used to optimize the hydrodynamic parameters of the heave plate, allowing maximum inertial forces in operational conditions, while simultaneously minimizing the forces generated in extreme waves. This presentation

  14. A Rigorous Analysis of Series-Connected, Multi-Bandgap, Tandem Thermophotovoltaic (TPV) Energy Converters

    NASA Astrophysics Data System (ADS)

    Wanlass, M. W.; Albin, D. S.

    2004-11-01

    Multi-bandgap, photonic energy conversion is under investigation for nearly every class of photovoltaic materials, with monolithic, series-connected device structures being the preferred mode of implementation. For TPV energy conversion systems, such an approach represents the next wave in TPV converter advancement. In this paper, we focus on a rigorous analysis of series-connected, multi-bandgap, tandem (SCMBT) converter structures according to Kirchhoff's circuit laws. A general formulation is presented, followed by an application of the general formulation to a typical, semi-realistic model for well-behaved, p-n junction, photovoltaic devices. Using results generated from a computer code written in Visual Basic, we then present example calculations for SCMBT TPV converters with two subcells, for a TPV system utilizing a blackbody radiator operating at 954°C (1750°F). A comparison of the results obtained using the rigorous analysis, with those obtained by using the commonly adopted subcell-photocurrent-matching design rule, is discussed in detail. An output power density increase of ˜ 5% is realized in the solution determined by the rigorous analysis, as compared to that obtained with the subcell-photocurrent-matching rule. Additional interesting, non-intuitive results are also highlighted.

  15. Modular assembly of a photovoltaic solar energy receiver

    DOEpatents

    Graven, Robert M.; Gorski, Anthony J.; Schertz, William W.; Graae, Johan E. A.

    1978-01-01

    There is provided a modular assembly of a solar energy concentrator having a photovoltaic energy receiver with passive cooling. Solar cell means are fixedly coupled to a radiant energy concentrator. Tension means bias a large area heat sink against the cell thereby allowing the cell to expand or contract with respect to the heat sink due to differential heat expansion.

  16. GaAs series connected photovoltaic converters for high voltage capacitor charging applications

    SciTech Connect

    Rose, B.H.

    1997-09-01

    This report describes the design features of series connected photovoltaic arrays which will be required to charge capacitors to relatively high (400V) voltages in time periods on the order of 1 microsecond. The factors which determine the array voltage and the capacitor charge time are given. Individual element junction designs, along with an interconnect scheme, and a semiconductor process to realize them are presented. Finally, the input laser optical required to meet the requirements is determined.

  17. Converting Sunlight to Mechanical Energy: A Polymer Example of Entropy.

    ERIC Educational Resources Information Center

    Mathias, Lon J.

    1987-01-01

    This experiment/demonstration provides elementary through high school science students with hands-on experience with polymer entropy. Construction of a simple machine for converting light into mechanical energy is described. (RH)

  18. Laser-to-electricity energy converter for short wavelengths

    NASA Technical Reports Server (NTRS)

    Stirn, R. J.; Yeh, Y. C. M.

    1975-01-01

    Short-wavelength energy converter can be made using Schottky barrier structure. It has wider band gap than p-n junction silicon semiconductors, and thus it has improved response at wavelengths down to and including ultraviolet region.

  19. Interim performance criteria for photovoltaic energy systems. [Glossary included

    SciTech Connect

    DeBlasio, R.; Forman, S.; Hogan, S.; Nuss, G.; Post, H.; Ross, R.; Schafft, H.

    1980-12-01

    This document is a response to the Photovoltaic Research, Development, and Demonstration Act of 1978 (P.L. 95-590) which required the generation of performance criteria for photovoltaic energy systems. Since the document is evolutionary and will be updated, the term interim is used. More than 50 experts in the photovoltaic field have contributed in the writing and review of the 179 performance criteria listed in this document. The performance criteria address characteristics of present-day photovoltaic systems that are of interest to manufacturers, government agencies, purchasers, and all others interested in various aspects of photovoltaic system performance and safety. The performance criteria apply to the system as a whole and to its possible subsystems: array, power conditioning, monitor and control, storage, cabling, and power distribution. They are further categorized according to the following performance attributes: electrical, thermal, mechanical/structural, safety, durability/reliability, installation/operation/maintenance, and building/site. Each criterion contains a statement of expected performance (nonprescriptive), a method of evaluation, and a commentary with further information or justification. Over 50 references for background information are also given. A glossary with definitions relevant to photovoltaic systems and a section on test methods are presented in the appendices. Twenty test methods are included to measure performance characteristics of the subsystem elements. These test methods and other parts of the document will be expanded or revised as future experience and needs dictate.

  20. Department of Energy: Photovoltaics program - FY 1996

    SciTech Connect

    1996-12-31

    The National Photovoltaic Program supports efforts to make PV an important part of the US economy through three main program elements: Research and Development, Technology Development, and Systems Engineering and Applications. (1) Research and Development activities generate new ideas, test the latest scientific theories, and push the limits of PV efficiencies in laboratory and prototype materials and devices. (2) Technology Development activities apply laboratory innovations to products to improve PV technology and the manufacturing techniques used to produce PV systems for the market. (3) Systems Engineering and Applications activities help improve PV systems and validate these improvements through tests, measurements, and deployment of prototypes. In addition, applications research validates, sales, maintenance, and financing mechanisms worldwide. (4) Environmental, Health, Safety and Resource Characterization activities help to define environmental, health and safety issues for those facilities engaged in the manufacture of PV products and organizations engaged in PV research and development. All PV Program activities are planned and executed in close collaboration and partnership with the U.S. PV industry. The overall PV Program is planned to be a balanced effort of research, manufacturing development, and market development. Critical to the success of this strategy is the National Photovoltaic Program`s effort to reduce the cost of electricity generated by photovoltaic. The program is doing this in three primary ways: by making devices more efficient, by making PV systems less expensive, and by validating the technology through measurements, tests, and prototypes.

  1. Converting acoustic energy into useful other energy forms

    DOEpatents

    Putterman, Seth J.; Barber, Bradley Paul; Hiller, Robert Anthony; Lofstedt, Ritva Maire Johanna

    1997-01-01

    Sonoluminescence is an off-equilibrium phenomenon in which the energy of a resonant sound wave in a liquid is highly concentrated so as to generate flashes of light. The conversion of sound to light represents an energy amplification of eleven orders of magnitude. The flashes which occur once per cycle of the audible or ultrasonic sound fields can be comprised of over one million photons and last for less 100 picoseconds. The emission displays a clocklike synchronicity; the jitter in time between consecutive flashes is less than fifty picoseconds. The emission is blue to the eye and has a broadband spectrum increasing from 700 nanometers to 200 nanometers. The peak power is about 100 milliWatts. The initial stage of the energy focusing is effected by the nonlinear oscillations of a gas bubble trapped in the liquid. For sufficiently high drive pressures an imploding shock wave is launched into the gas by the collapsing bubble. The reflection of the shock from its focal point results in high temperatures and pressures. The sonoluminescence light emission can be sustained by sensing a characteristic of the emission and feeding back changes into the driving mechanism. The liquid is in a sealed container and the seeding of the gas bubble is effected by locally heating the liquid after sealing the container. Different energy forms than light can be obtained from the converted acoustic energy. When the gas contains deuterium and tritium there is the feasibility of the other energy form being fusion, namely including the generation of neutrons.

  2. Building integrated semi-transparent photovoltaics: energy and daylighting performance

    NASA Astrophysics Data System (ADS)

    Kapsis, Konstantinos; Athienitis, Andreas K.

    2011-08-01

    This paper focuses on modeling and evaluation of semi-transparent photovoltaic technologies integrated into a coolingdominated office building façade by employing the concept of three-section façade. An energy simulation model is developed, using building simulation software, to investigate the effect of semi-transparent photovoltaic transmittance on the energy performance of an office in a typical office building in Montreal. The analysis is performed for five major façade orientations and two façade configurations. Using semi-transparent photovoltaic integrated into the office façade, electricity savings of up to 53.1% can be achieved compared to a typical office equipped with double glazing with Argon filling and a low emissivity coating, and lighting controlled based on occupancy and daylight levels.e.c

  3. Moving core beam energy absorber and converter

    DOEpatents

    Degtiarenko, Pavel V.

    2012-12-18

    A method and apparatus for the prevention of overheating of laser or particle beam impact zones through the use of a moving-in-the-coolant-flow arrangement for the energy absorbing core of the device. Moving of the core spreads the energy deposition in it in 1, 2, or 3 dimensions, thus increasing the effective cooling area of the device.

  4. Photovoltaic Energy Valuation Model v 1.0

    SciTech Connect

    Klise Jamie Johnson, Geoffrey T.

    2012-01-09

    Currently, there is a need identified by Kennecott Land, as well as others in the real estate, appraisal and building industry to come up with a tool that is simple to use and can accurately value the electricity produced by a solar photovoltaic system. In the appraisal industry, comparable properties are used to help in the valuation of a residential property. Absent a comparable feature such as photovoltaic panels on a neighboring property, it is difficult for appraisers to assign a value to that system. In many cases, photovoltaic systems are assigned a value of $0, which essentially ignores the value of energy being produced and being saved by the homeowner relative to the cost of energy they would otherwise have to purchase from the local utility. There are multiple programs that can calculate the value of the energy produced in terms of the payback period and desired internal rate of return, but none employ the concept of discounting the future value of the energy produced at any period in the expected lifetime of a photovoltaic energy system. By creating this spreadsheet, a necessary gap has been filled. It is the expectation that this product will be included in training programs aimed towards the local appraisal community in Salt Lake County, Utah as well as expand into training offered at the national level through the Appraisal Institute. This software product is an excel spreadsheet that is used to calculate the present value of future energy production for photovoltaic electricity generating systems on residential and commercial properties. Visual Basic (VB) code within the spreadsheet allows user data to be passed to the PVWatts System Advisor Model webservice (http://www.nrel.gov/rredc/pvwatts/) and back into the spreadsheet to estimate the annual solar energy production in Salt Lake County, Utah (as well as anywhere in the U.S.). VB is also used for a discount rate calculation and calls the most current Fannie Mae 30-Year Fixed Rate 60-day

  5. AlGaAs/GaAs photovoltaic converters for high power narrowband radiation

    SciTech Connect

    Khvostikov, Vladimir; Kalyuzhnyy, Nikolay; Mintairov, Sergey; Potapovich, Nataliia; Shvarts, Maxim; Sorokina, Svetlana; Andreev, Viacheslav; Luque, Antonio

    2014-09-26

    AlGaAs/GaAs-based laser power PV converters intended for operation with high-power (up to 100 W/cm{sup 2}) radiation were fabricated by LPE and MOCVD techniques. Monochromatic (λ = 809 nm) conversion efficiency up to 60% was measured at cells with back surface field and low (x = 0.2) Al concentration 'window'. Modules with a voltage of 4 V and the efficiency of 56% were designed and fabricated.

  6. Photovoltaic and thermal energy conversion for solar powered satellites

    NASA Technical Reports Server (NTRS)

    Von Tiesenhausen, G. F.

    1976-01-01

    A summary is provided concerning the most important aspects of present investigations related to a use of solar power satellites (SPS) as a future source of terrestrial energy. General SPS characteristics are briefly considered, early work is reviewed, and a description of current investigations is presented. System options presently under study include a photovoltaic array, a thermionic system, and a closed Brayton cycle. Attention is given to system reference options, basic building blocks, questions of system analysis and engineering, photovoltaic conversion, and the utility interface. It is concluded that an SPS may be cost effective compared to terrestrial systems by 1995.

  7. Energy Savings Assessment for Digital-to-Analog Converter Boxes

    SciTech Connect

    Cheung, Hoi Ying Iris; Meier, Alan; Brown, Richard

    2011-01-18

    The Digital Television (DTV) Converter Box Coupon Program was administered by the U.S. government to subsidize purchases of digital-to-analog converter boxes, with up to two $40 coupons for each eligible household. In order to qualify as Coupon Eligible Converter Boxes (CECBs), these devices had to meet a number of minimum performance specifications, including energy efficiency standards. The Energy Star Program also established voluntary energy efficiency specifications that are more stringent than the CECB requirements. In this study, we measured the power and energy consumptions for a sample of 12 CECBs (including 6 Energy Star labeled models) in-use in homes and estimated aggregate energy savings produced by the energy efficiency policies. Based on the 35 million coupons redeemed through the end of the program, our analysis indicates that between 2500 and 3700 GWh per year are saved as a result of the energy efficiency policies implemented on digital-to-analog converter boxes. The energy savings generated are equivalent to the annual electricity use of 280,000 average US homes.

  8. Photovoltaic energy: Program overview, fiscal year 1990

    SciTech Connect

    Not Available

    1991-07-01

    This summary is prepared each year to provide an overview of the government-funded activities within the National Photovoltaics Program. The 1990 PV Program Achievements are listed. Launched the PV Manufacturing Technology initiative, designed to systematically lower PV module costs. Inaugurated the PV Concentrator Technologies Initiative by signing eight multiyear, cost-shared technology development subcontracts with concentrator companies. Established the PV Polycrystalline Thin-Film Initiative by signing six multiyear, cost-shared technology development subcontracts with six polycrystalline thin-film companies. Continued the Amorphous Silicon Project by awarding three new research and development contracts. Focused the resources of three program laboratories on finding solutions to industry's manufacturing problems: the Photovoltaic Device Fabrication Laboratory at Sandia National Laboratories and the Module Failure Analysis Laboratory and the Encapsulant Research Laboratory at SERI. Established an ongoing program to assist utilities in using PV for cost-effective, high-value applications. Completed nearly all of the construction planned for the first phase of PVUSA at Davis, California. Worked with the crystalline silicon PV industry on novel, low-cost cell fabrication processes and on resolving encapsulant problems. Took part in the development of qualification procedures tests for thin- and thick-film flat-plate modules and concentrator modules.

  9. Standards for photovoltaic energy conversion systems. Final report

    SciTech Connect

    Schafft, H. A.

    1980-04-01

    This report provides the results of a search for existing domestic standards and related documents for possible application in the development of a standards base for photovoltaic energy conversion systems. The search resulted in locating about 150 test methods, recommended practices, standards, solar-thermal performance criteria, and other standards-related documents. They are listed by topic areas in the appendix. The listing was prepared to assist those involved in developing performance criteria for photovoltaic systems and in identifying methods to test system performance against these criteria. It is clear from the results of the search that few standards are directly applicable to terrestrial solar photovoltaic systems and that much standards development is required to support the commercialization of such systems.

  10. Photovoltaic energy systems: environmental concerns and control technology needs

    SciTech Connect

    Moskowitz, P.D.; Perry, P.; Wilenitz, I.

    1982-11-01

    Technical and commercial readiness for alternate photovoltaic energy systems, and waste streams from three different photovoltaic systems are examined. This analysis suggests that some uncontrolled waste streams could be declared toxic or hazardous under various provisions of the Clean Air, Clean Water, and Resource and Conservation Recovery Acts. Although some processes could emit large quantities of pollutants, these can be controlled using available technology. Other processes may emit small quantities of more toxic pollutants which will probably not be directly controlled unless significant health hazards are identified. Environmental problems in installation and operation are probably associated with large central-station applications; no significant effects are expected from small decentralized applications. Decommissioning of broken or degraded photovoltaic systems will generate large quantities of solid waste which can be simply disposed of in a landfill or perhaps recycled.

  11. Development of a wind converter and investigation of its operational function. Part 1: Technical description of the wind energy converter

    NASA Astrophysics Data System (ADS)

    Molly, J. P.; Steinheber, R.

    1982-11-01

    A 10 kW wind energy converter was developed by using as far possible standard serial production parts. The design criteria and the description of the essential machinery components of the MODA 10 wind energy converter are discussed. For some special load cases the safety calculation of the important components is shown. The blade control system which qualified for small wind energy converters, is explained. Weight and cost of the MODA 10 are considered.

  12. An Optimal Control Strategy for DC Bus Voltage Regulation in Photovoltaic System with Battery Energy Storage

    PubMed Central

    Daud, Muhamad Zalani; Mohamed, Azah; Hannan, M. A.

    2014-01-01

    This paper presents an evaluation of an optimal DC bus voltage regulation strategy for grid-connected photovoltaic (PV) system with battery energy storage (BES). The BES is connected to the PV system DC bus using a DC/DC buck-boost converter. The converter facilitates the BES power charge/discharge to compensate for the DC bus voltage deviation during severe disturbance conditions. In this way, the regulation of DC bus voltage of the PV/BES system can be enhanced as compared to the conventional regulation that is solely based on the voltage-sourced converter (VSC). For the grid side VSC (G-VSC), two control methods, namely, the voltage-mode and current-mode controls, are applied. For control parameter optimization, the simplex optimization technique is applied for the G-VSC voltage- and current-mode controls, including the BES DC/DC buck-boost converter controllers. A new set of optimized parameters are obtained for each of the power converters for comparison purposes. The PSCAD/EMTDC-based simulation case studies are presented to evaluate the performance of the proposed optimized control scheme in comparison to the conventional methods. PMID:24883374

  13. An optimal control strategy for DC bus voltage regulation in photovoltaic system with battery energy storage.

    PubMed

    Daud, Muhamad Zalani; Mohamed, Azah; Hannan, M A

    2014-01-01

    This paper presents an evaluation of an optimal DC bus voltage regulation strategy for grid-connected photovoltaic (PV) system with battery energy storage (BES). The BES is connected to the PV system DC bus using a DC/DC buck-boost converter. The converter facilitates the BES power charge/discharge to compensate for the DC bus voltage deviation during severe disturbance conditions. In this way, the regulation of DC bus voltage of the PV/BES system can be enhanced as compared to the conventional regulation that is solely based on the voltage-sourced converter (VSC). For the grid side VSC (G-VSC), two control methods, namely, the voltage-mode and current-mode controls, are applied. For control parameter optimization, the simplex optimization technique is applied for the G-VSC voltage- and current-mode controls, including the BES DC/DC buck-boost converter controllers. A new set of optimized parameters are obtained for each of the power converters for comparison purposes. The PSCAD/EMTDC-based simulation case studies are presented to evaluate the performance of the proposed optimized control scheme in comparison to the conventional methods. PMID:24883374

  14. Solar photovoltaic/thermal (hybrid) energy project

    NASA Astrophysics Data System (ADS)

    Sheldon, D. B.

    1981-09-01

    Development of photovoltaic/thermal (PV/T) collectors and residential heat pump systems is reported. Candidate collector and residential heat pump systems were evaluated using the TRNSYS computer program. It is found that combined heat pump and PV array is a promising method for achieving economical solar cooling. Where the cooling load is dominant, exclusively PV collectors rather than PV/T collectors are preferred. Where the heating load is dominant, the thermal component of PV/T collectors makes a significant contribution to heating a residence. PV/T collectors were developed whose combined efficiency approaches the efficiency of a double glazed, exclusively thermal collector. The design and operational problems of air source heat pumps are reviewed. Possible effects of compressor startup transients on PV power system operation are discussed.

  15. Performance of an angular flange aeroelastic wind energy converter

    SciTech Connect

    Ahmadi, G.

    1983-05-01

    ALL conventional wind turbines operate on the principles of turbomachinaries, with wind being made to flow over a set of rotating vanes. Recently, a new concept for wind energy conversion based on aeroelastic instability was introduced. It is well known that couplings between the vibration of an elastic structure and fluid stream may lead to aeroelastic instability. Energy then is transferred from the airstream into the elastic structure, which results in a destructive monotonic increase of the vibration amplitude of the structure. The failure of the Tacoma Narrows Bridge is one of the well-known examples of such a disaster. The use of an aeroelastic instability (or flutter) mechanism for constructing a wind energy converter was suggested. The theory for a torsional wind energy converter and the results of some model tests were also presented. Recently, some studies on similar types of wind energy converters using oscillating airfoils were reported. In the present study an angular flange H-section model of a torsional aeroelastic wind energy converter is constructed, and its performances under various conditions are investigated. The effects of the variations of the flange angle and the flange width on the performance of the model are studied. The weight of the pendulum is also varied, and its effects on the power coefficient of the model are investigated. It is observed that the efficiency of energy conversion decreases with an increase in wind speed. A method for possible improvement of the theoretical prediction is suggested and discussed.

  16. Microbial fuel cell energy harvesting using synchronous flyback converter

    NASA Astrophysics Data System (ADS)

    Alaraj, Muhannad; Ren, Zhiyong Jason; Park, Jae-Do

    2014-02-01

    Microbial Fuel Cells (MFCs) use biodegradable substrates, such as wastewater and marine sediments to generate electrical energy. To harvest more energy from an MFC, power electronic converters have recently been used to replace resistors or charge pumps, because they have superior controllability on MFC's operating point and higher efficiency in energy storage for different applications. Conventional diode-based energy harvesters suffer from low efficiency because of the energy losses through the diode. Replacing the diode with a MOSFET can reduce the conduction loss, but it requires an isolated gate signal to control the floating secondary MOSFET, which makes the control circuitry complex. This study presents a new MFC energy harvesting regime using a synchronous flyback converter, which implements a transformer-based harvester with much simpler configuration and improves harvesting efficiency by 37.6% compared to a diode based boost converter, from 33.5% to 46.1%. The proposed harvester was able to store 2.27 J in the output capacitor out of 4.91 J generated energy from the MFC, while the boost converter can capture 1.67 J from 4.95 J.

  17. Converting energy to medical progress [nuclear medicine

    SciTech Connect

    2001-04-01

    For over 50 years the Office of Biological and Environmental Research (BER) of the United States Department of Energy (DOE) has been investing to advance environmental and biomedical knowledge connected to energy. The BER Medical Sciences program fosters research to develop beneficial applications of nuclear technologies for medical diagnosis and treatment of many diseases. Today, nuclear medicine helps millions of patients annually in the United States. Nearly every nuclear medicine scan or test used today was made possible by past BER-funded research on radiotracers, radiation detection devices, gamma cameras, PET and SPECT scanners, and computer science. The heart of biological research within BER has always been the pursuit of improved human health. The nuclear medicine of tomorrow will depend greatly on today's BER-supported research, particularly in the discovery of radiopharmaceuticals that seek specific molecular and genetic targets, the design of advanced scanners needed to create meaningful images with these future radiotracers, and the promise of new radiopharmaceutical treatments for cancers and genetic diseases.

  18. Converting Energy to Medical Progress [Nuclear Medicine

    DOE R&D Accomplishments Database

    2001-04-01

    For over 50 years the Office of Biological and Environmental Research (BER) of the United States Department of Energy (DOE) has been investing to advance environmental and biomedical knowledge connected to energy. The BER Medical Sciences program fosters research to develop beneficial applications of nuclear technologies for medical diagnosis and treatment of many diseases. Today, nuclear medicine helps millions of patients annually in the United States. Nearly every nuclear medicine scan or test used today was made possible by past BER-funded research on radiotracers, radiation detection devices, gamma cameras, PET and SPECT scanners, and computer science. The heart of biological research within BER has always been the pursuit of improved human health. The nuclear medicine of tomorrow will depend greatly on today's BER-supported research, particularly in the discovery of radiopharmaceuticals that seek specific molecular and genetic targets, the design of advanced scanners needed to create meaningful images with these future radiotracers, and the promise of new radiopharmaceutical treatments for cancers and genetic diseases.

  19. Investigation of potential islanding of a self-commutated static power converter in photovoltaic systems

    SciTech Connect

    Jones, R.A.; Sims, T.R. ); Imece, A.F. )

    1990-12-01

    One of the major concerns of utilities about the impact of dispersed PV generation is islanding or the continued operation of a portion of the system, after it has been disconnected from the utility. This paper presents a summary of the results of a research project on the islanding potential of a Teslaco self-commutated static power converter (SPC). This project included computer simulations, laboratory testing, and field testing. Laboratory and field tests verified that the SPC model developed for computer simulations accurately predicts SPC islanding performance under a variety of system conditions. Furthermore, the impact of a number of system parameters on the islanding potential are presented. These include the mismatch between load and generation within the island, the type of load within the island, the number of SPCs within the island, load variations, and solar insolation variations.

  20. An approach for modeling self-commutated static power converters for photovoltaic islanding studies

    SciTech Connect

    Imece, A.F. . Systems Development and Engineering Dept.); Jones, R.A.; Sims, T.R. ); Gross, C.A. . Dept. of Electrical Engineering)

    1989-09-01

    The safety of line crew personnel and others is a major concern of electric power utilities regarding the widespread use of grid-connected photo-volataic (PV) power sources. PV sources feed power back to a utility grid through Static Power Converters (SPC's), which are designed to shut down when disconnected from the grid. SPC's have been shown to continue to operate or run-on under certain conditions. A model for a commercially available self-commutated SPC is developed to investigate the conditions under which isolated operation (islanding) occurs. The approach used in modeling the SPC is unique in islanding studies. It is based on solving complex-ac system equations and Phase-Locked Loop differential equations simultaneously to determine the SPC response. The model accurately and optimistically predicts the islanding performance of the self-commutated SPC, as verified in laboratory experiments and detailed computer simulations.

  1. Photovoltaic solar energy conversion in the '80s

    NASA Astrophysics Data System (ADS)

    Chevalier, I.

    1981-04-01

    The potential for photovoltaic solar energy conversion in the generation of electricity to meet the needs of industrial and developing nations in the 1980s is discussed. The current technology of photovoltaic cells and modules, which are for the most part based on single crystal silicon and can deliver peak powers of 2 to 40 W at 6 to 12 V, is reviewed and prospects for cost reduction in the short- and medium-term by the development of new materials and production methods and increased cell efficiency and in the long term by the development of thin film cells, alternative compounds and mass production are indicated. Possible applications of photovoltaic-derived electricity are pointed out, including educational television receivers, rural telephones, refrigerators, water pumping and hospitals in developing nations and telecommunications, cathodic protection, signaling, telemetry and low-power pumping applications in industrial nations. Predictions of a photovoltaic peak Watt installed costing less than 10 francs by 1990 and a market above 100 MW in 1985 are pointed out.

  2. Rectenna that converts infrared radiation to electrical energy

    DOEpatents

    Davids, Paul; Peters, David W.

    2016-09-06

    Technologies pertaining to converting infrared (IR) radiation to DC energy are described herein. In a general embodiment, a rectenna comprises a conductive layer. A thin insulator layer is formed on the conductive layer, and a nanoantenna is formed on the thin insulator layer. The thin insulator layer acts as a tunnel junction of a tunnel diode.

  3. Solar breeder: Energy payback time for silicon photovoltaic systems

    NASA Technical Reports Server (NTRS)

    Lindmayer, J.

    1977-01-01

    The energy expenditures of the prevailing manufacturing technology of terrestrial photovoltaic cells and panels were evaluated, including silicon reduction, silicon refinement, crystal growth, cell processing and panel building. Energy expenditures include direct energy, indirect energy, and energy in the form of equipment and overhead expenses. Payback times were development using a conventional solar cell as a test vehicle which allows for the comparison of its energy generating capability with the energies expended during the production process. It was found that the energy payback time for a typical solar panel produced by the prevailing technology is 6.4 years. Furthermore, this value drops to 3.8 years under more favorable conditions. Moreover, since the major energy use reductions in terrestrial manufacturing have occurred in cell processing, this payback time directly illustrates the areas where major future energy reductions can be made -- silicon refinement, crystal growth, and panel building.

  4. Finite element analysis of combined magnetoelectric- electrodynamic vibration energy converter

    NASA Astrophysics Data System (ADS)

    Bradai, Sonia; Naifar, Slim; Kanoun, Olfa

    2015-12-01

    In this paper we report on the design and optimization of a novel combined vibration energy harvester based on the use of electrodynamic and magnetoelectric (ME) principles to increase the energy outcome of an electrodynamic harvester without significantly increasing its size. Thereby the most important aspect is the dependence of magnetic flux variation on design parameters, as is it is the decisive effect for energy conversion. Magnetic circuit form and magnetization are optimized for maximizing energy outcome. We conclude that better magnetic flux variation is reached for a magnetic circuit formed with two magnets stacked one within the other using the same magnetization. Results illustrate that the use of combined converter enables to enhance the performance of simple electrodynamic or ME converter.

  5. Photovoltaic Energy Valuation Model v 1.0

    Energy Science and Technology Software Center (ESTSC)

    2012-01-09

    Currently, there is a need identified by Kennecott Land, as well as others in the real estate, appraisal and building industry to come up with a tool that is simple to use and can accurately value the electricity produced by a solar photovoltaic system. In the appraisal industry, comparable properties are used to help in the valuation of a residential property. Absent a comparable feature such as photovoltaic panels on a neighboring property, it ismore » difficult for appraisers to assign a value to that system. In many cases, photovoltaic systems are assigned a value of $0, which essentially ignores the value of energy being produced and being saved by the homeowner relative to the cost of energy they would otherwise have to purchase from the local utility. There are multiple programs that can calculate the value of the energy produced in terms of the payback period and desired internal rate of return, but none employ the concept of discounting the future value of the energy produced at any period in the expected lifetime of a photovoltaic energy system. By creating this spreadsheet, a necessary gap has been filled. It is the expectation that this product will be included in training programs aimed towards the local appraisal community in Salt Lake County, Utah as well as expand into training offered at the national level through the Appraisal Institute. This software product is an excel spreadsheet that is used to calculate the present value of future energy production for photovoltaic electricity generating systems on residential and commercial properties. Visual Basic (VB) code within the spreadsheet allows user data to be passed to the PVWatts System Advisor Model webservice (http://www.nrel.gov/rredc/pvwatts/) and back into the spreadsheet to estimate the annual solar energy production in Salt Lake County, Utah (as well as anywhere in the U.S.). VB is also used for a discount rate calculation and calls the most current Fannie Mae 30-Year Fixed Rate 60-day

  6. Hydrogen as the solar energy translator. [in photochemical and photovoltaic processes

    NASA Technical Reports Server (NTRS)

    Kelley, J. H.

    1979-01-01

    Many concepts are being investigated to convert sunlight to workable energy forms with emphasis on electricity and thermal energy. The electrical alternatives include direct conversion of photons to electricity via photovoltaic solar cells and solar/thermal production of electricity via heat-energy cycles. Solar cells, when commercialized, are expected to have efficiencies of about 12 to 14 percent. The cells would be active about eight hours per day. However, solar-operated water-splitting process research, initiated through JPL, shows promise for direct production of hydrogen from sunlight with efficiencies of up to 35 to 40 percent. The hydrogen, a valuable commodity in itself, can also serve as a storable energy form, easily and efficiently converted to electricity by fuel cells and other advanced-technology devices on a 24-hour basis or on demand with an overall efficiency of 25 to 30 percent. Thus, hydrogen serves as the fundamental translator of energy from its solar form to electrical form more effectively, and possibly more efficiently, than direct conversion. Hydrogen also can produce other chemical energy forms using solar energy.

  7. A novel design of DC-AC electrical machine rotary converter for hybrid solar and wind energy applications

    NASA Astrophysics Data System (ADS)

    Mohammed, K. G.; Ramli, A. Q.; Amirulddin, U. A. U.

    2013-06-01

    This paper proposes the design of a new bi-directional DC-AC rotary converter machine to convert a d.c. voltage to three-phase voltage and vice-versa using a two-stage energy conversion machine. The rotary converter consists of two main stages which are combined into single frame. These two stages are constructed from three main electromagnetic components. The first inner electromagnetic component represents the input stage that enables the DC power generated by solar energy from photo-voltaic cells to be transformed by the second and third components electro-magnetically to produce multi-phase voltages at the output stage. At the same time, extra kinetic energy from wind, which is sufficiently available, can be added to existing torque on the second electromagnetic component. Both of these input energies will add up to the final energy generated at the output terminals. Therefore, the machine will be able to convert solar and wind energies to the output terminals simultaneously. If the solar energy is low, the available wind energy will be able to provide energy to the output terminals and at the same time charges the batteries which are connected as backup system. At this moment, the machine behaves as wind turbine. The energy output from the machine benefits from two energy sources which are solar and wind. At night when the solar energy is not available and also the load is low, the wind energy is able to charge the batteries and at the same time provides output electrical power to the remaining the load. Therefore, the proposed system will have high usage of available renewable energy as compared to separated wind or solar systems. MATLAB codes are used to calculate the required dimensions, the magnetic and electrical circuits parameters to design of the new bi-directional rotary converter machine.

  8. Stochastic Control of Inertial Sea Wave Energy Converter

    PubMed Central

    Mattiazzo, Giuliana; Giorcelli, Ermanno

    2015-01-01

    The ISWEC (inertial sea wave energy converter) is presented, its control problems are stated, and an optimal control strategy is introduced. As the aim of the device is energy conversion, the mean absorbed power by ISWEC is calculated for a plane 2D irregular sea state. The response of the WEC (wave energy converter) is driven by the sea-surface elevation, which is modeled by a stationary and homogeneous zero mean Gaussian stochastic process. System equations are linearized thus simplifying the numerical model of the device. The resulting response is obtained as the output of the coupled mechanic-hydrodynamic model of the device. A stochastic suboptimal controller, derived from optimal control theory, is defined and applied to ISWEC. Results of this approach have been compared with the ones obtained with a linear spring-damper controller, highlighting the capability to obtain a higher value of mean extracted power despite higher power peaks. PMID:25874267

  9. Photovoltaics: alternative energy opportunities in Egypt

    SciTech Connect

    Gadomski, C.R.

    1987-10-01

    Government subsidies for electricity have discouraged the growth of an alternative energy market, but economic problems and high utility bills are changing the market as the demand for electricity expands. Although the past five-year plan only called for five percent of Egypt's energy to come from renewable sources, the development of solar power plants, wind power, and resource recovery could raise that to seven percent. Planners are looking to joint ventures and technology transfers to get the stagnant alternative energy industry moving. 2 figures.

  10. SOLCOST-PHOTOVOLTAIC solar energy design program: User's Guide

    SciTech Connect

    Not Available

    1980-10-01

    The SOLCOST-PHOTOVOLTAIC solar energy design program is a public domain interactive computer design tool intended for use by non-solar specialists to predict the long term performance for photovoltaic systems. A life cycle cost analysis is included in the program along with the ERDA-EPRI standard economic analysis which predicts levelized busbar energy costs for the photovoltaic system assuming ownership by an electric utility. SOLCOST-PV currently can evaluate flat plate arrays and concentrating arrays which use Fresnel lenses and passive cooling. The methodology could easily be extended to include all the known types of concentrators, however the scope of the version 1.0 activity was limited to only the flat plate and the passive Fresnel concentrators. An overview of the SOLCOST-PV capabilities and methodology is given. A detailed guide to the SOLCOST-PV input parameters is included, and examples showing typical interactive execution sessions and the resulting SOLCOST-PV output are presented. Appendices A and B provide additional information on the SOLCOST-PV analysis.

  11. Tandem photovoltaic solar cells and increased solar energy conversion efficiency

    NASA Technical Reports Server (NTRS)

    Loferski, J. J.

    1976-01-01

    Tandem photovoltaic cells, as proposed by Jackson (1955) to increase the efficiency of solar energy conversion, involve the construction of a system of stacked p/n homojunction photovoltaic cells composed of different semiconductors. It had been pointed out by critics, however, that the total power which could be extracted from the cells in the stack placed side by side was substantially greater than the power obtained from the stacked cells. A reexamination of the tandem cell concept in view of the development of the past few years is conducted. It is concluded that the use of tandem cell systems in flat plate collectors, as originally envisioned by Jackson, may yet become feasible as a result of the development of economically acceptable solar cells for large scale terrestrial power generation.

  12. Modularized multilevel and z-source power converter as renewable energy interface for vehicle and grid-connected applications

    NASA Astrophysics Data System (ADS)

    Cao, Dong

    Due the energy crisis and increased oil price, renewable energy sources such as photovoltaic panel, wind turbine, or thermoelectric generation module, are used more and more widely for vehicle and grid-connected applications. However, the output of these renewable energy sources varies according to different solar radiation, wind speed, or temperature difference, a power converter interface is required for the vehicle or grid-connected applications. Thermoelectric generation (TEG) module as a renewable energy source for automotive industry is becoming very popular recently. Because of the inherent characteristics of TEG modules, a low input voltage, high input current and high voltage gain dc-dc converters are needed for the automotive load. Traditional high voltage gain dc-dc converters are not suitable for automotive application in terms of size and high temperature operation. Switched-capacitor dc-dc converters have to be used for this application. However, high voltage spike and EMI problems exist in traditional switched-capacitor dc-dc converters. Huge capacitor banks have to be utilized to reduce the voltage ripple and achieve high efficiency. A series of zero current switching (ZCS) or zero voltage switching switched-capacitor dc-dc converters have been proposed to overcome the aforementioned problems of the traditional switched-capacitor dc-dc converters. By using the proposed soft-switching strategy, high voltage spike is reduced, high EMI noise is restricted, and the huge capacitor bank is eliminated. High efficiency, high power density and high temperature switched-capacitor dc-dc converters could be made for the TEG interface in vehicle applications. Several prototypes have been made to validate the proposed circuit and confirm the circuit operation. In order to apply PV panel for grid-connected application, a low cost dc-ac inverter interface is required. From the use of transformer and safety concern, two different solutions can be implemented, non

  13. Aiding Design of Wave Energy Converters via Computational Simulations

    NASA Astrophysics Data System (ADS)

    Jebeli Aqdam, Hejar; Ahmadi, Babak; Raessi, Mehdi; Tootkaboni, Mazdak

    2015-11-01

    With the increasing interest in renewable energy sources, wave energy converters will continue to gain attention as a viable alternative to current electricity production methods. It is therefore crucial to develop computational tools for the design and analysis of wave energy converters. A successful design requires balance between the design performance and cost. Here an analytical solution is used for the approximate analysis of interactions between a flap-type wave energy converter (WEC) and waves. The method is verified using other flow solvers and experimental test cases. Then the model is used in conjunction with a powerful heuristic optimization engine, Charged System Search (CSS) to explore the WEC design space. CSS is inspired by charged particles behavior. It searches the design space by considering candidate answers as charged particles and moving them based on the Coulomb's laws of electrostatics and Newton's laws of motion to find the global optimum. Finally the impacts of changes in different design parameters on the power takeout of the superior WEC designs are investigated. National Science Foundation, CBET-1236462.

  14. Maximum wind energy extraction strategies using power electronic converters

    NASA Astrophysics Data System (ADS)

    Wang, Quincy Qing

    2003-10-01

    This thesis focuses on maximum wind energy extraction strategies for achieving the highest energy output of variable speed wind turbine power generation systems. Power electronic converters and controls provide the basic platform to accomplish the research of this thesis in both hardware and software aspects. In order to send wind energy to a utility grid, a variable speed wind turbine requires a power electronic converter to convert a variable voltage variable frequency source into a fixed voltage fixed frequency supply. Generic single-phase and three-phase converter topologies, converter control methods for wind power generation, as well as the developed direct drive generator, are introduced in the thesis for establishing variable-speed wind energy conversion systems. Variable speed wind power generation system modeling and simulation are essential methods both for understanding the system behavior and for developing advanced system control strategies. Wind generation system components, including wind turbine, 1-phase IGBT inverter, 3-phase IGBT inverter, synchronous generator, and rectifier, are modeled in this thesis using MATLAB/SIMULINK. The simulation results have been verified by a commercial simulation software package, PSIM, and confirmed by field test results. Since the dynamic time constants for these individual models are much different, a creative approach has also been developed in this thesis to combine these models for entire wind power generation system simulation. An advanced maximum wind energy extraction strategy relies not only on proper system hardware design, but also on sophisticated software control algorithms. Based on literature review and computer simulation on wind turbine control algorithms, an intelligent maximum wind energy extraction control algorithm is proposed in this thesis. This algorithm has a unique on-line adaptation and optimization capability, which is able to achieve maximum wind energy conversion efficiency through

  15. Differential Power Processing for Increased Energy Production and Reliability of Photovoltaic Systems

    SciTech Connect

    Shenoy, PS; Kim, KA; Johnson, BB; Krein, PT

    2013-06-01

    Conventional energy conversion architectures in photovoltaic (PV) systems are often forced to tradeoff conversion efficiency and power production. This paper introduces an energy conversion approach that enables each PV element to operate at its maximum power point (MPP) while processing only a small fraction of the total power produced. This is accomplished by providing only the mismatch in the MPP current of a set of series-connected PV elements. Differential power processing increases overall conversion efficiency and overcomes the challenges associated with unmatched MPPs (due to partial shading, damage, manufacturing tolerances, etc.). Several differential power processing architectures are analyzed and compared with Monte Carlo simulations. Local control of the differential converters enables distributed protection and monitoring. Reliability analysis shows significantly increased overall system reliability. Simulation and experimental results are included to demonstrate the benefits of this approach at both the panel and subpanel level.

  16. The Redox Flow System for solar photovoltaic energy storage

    NASA Technical Reports Server (NTRS)

    Odonnell, P.; Gahn, R. F.; Pfeiffer, W.

    1976-01-01

    The interfacing of a Solar Photovoltaic System and a Redox Flow System for storage was workable. The Redox Flow System, which utilizes the oxidation-reduction capability of two redox couples, in this case iron and titanium, for its storage capacity, gave a relatively constant output regardless of solar activity so that a load could be run continually day and night utilizing the sun's energy. One portion of the system was connected to a bank of solar cells to electrochemically charge the solutions, while a separate part of the system was used to electrochemically discharge the stored energy.

  17. Graphene-Based Integrated Photovoltaic Energy Harvesting/Storage Device.

    PubMed

    Chien, Chih-Tao; Hiralal, Pritesh; Wang, Di-Yan; Huang, I-Sheng; Chen, Chia-Chun; Chen, Chun-Wei; Amaratunga, Gehan A J

    2015-06-24

    Energy scavenging has become a fundamental part of ubiquitous sensor networks. Of all the scavenging technologies, solar has the highest power density available. However, the energy source is erratic. Integrating energy conversion and storage devices is a viable route to obtain self-powered electronic systems which have long-term maintenance-free operation. In this work, we demonstrate an integrated-power-sheet, consisting of a string of series connected organic photovoltaic cells (OPCs) and graphene supercapacitors on a single substrate, using graphene as a common platform. This results in lighter and more flexible power packs. Graphene is used in different forms and qualities for different functions. Chemical vapor deposition grown high quality graphene is used as a transparent conductor, while solution exfoliated graphene pastes are used as supercapacitor electrodes. Solution-based coating techniques are used to deposit the separate components onto a single substrate, making the process compatible with roll-to-roll manufacture. Eight series connected OPCs based on poly(3-hexylthiophene)(P3HT):phenyl-C61-butyric acid methyl ester (PC60 BM) bulk-heterojunction cells with aluminum electrodes, resulting in a ≈5 V open-circuit voltage, provide the energy harvesting capability. Supercapacitors based on graphene ink with ≈2.5 mF cm(-2) capacitance provide the energy storage capability. The integrated-power-sheet with photovoltaic (PV) energy harvesting and storage functions had a mass of 0.35 g plus the substrate. PMID:25703342

  18. Method for converting one form of energy into another form of energy

    SciTech Connect

    Anno, J.N.; Fawcett, S.L.

    1983-05-31

    Method for converting one form of energy into another form of energy by isobarically heating a gas, adiabatically expanding the gas while converting the heat energy of the gas into the kinetic energy of a moving body, converting the kinetic energy of the moving body into another form of energy, and approximately isothermally compressing the gas to a higher pressure. Improved efficiency is achieved by virtue of the fact that this system employs approximately isothermal compression, which is preferably achieved by injecting liquid into an adiabatically-expanded gas, thereby effecting a thermodynamic cycle which more closely approximates the efficiency of a carnot cycle.

  19. Photovoltaic module energy rating methodology development

    SciTech Connect

    Kroposki, B.; Myers, D.; Emery, K.; Mrig, L.; Whitaker, C.; Newmiller, J.

    1996-05-01

    A consensus-based methodology to calculate the energy output of a PV module will be described in this paper. The methodology develops a simple measure of PV module performance that provides for a realistic estimate of how a module will perform in specific applications. The approach makes use of the weather data profiles that describe conditions throughout the United States and emphasizes performance differences between various module types. An industry-representative Technical Review Committee has been assembled to provide feedback and guidance on the strawman and final approach used in developing the methodology.

  20. Nonlinear predictive energy management of residential buildings with photovoltaics & batteries

    NASA Astrophysics Data System (ADS)

    Sun, Chao; Sun, Fengchun; Moura, Scott J.

    2016-09-01

    This paper studies a nonlinear predictive energy management strategy for a residential building with a rooftop photovoltaic (PV) system and second-life lithium-ion battery energy storage. A key novelty of this manuscript is closing the gap between building energy management formulations, advanced load forecasting techniques, and nonlinear battery/PV models. Additionally, we focus on the fundamental trade-off between lithium-ion battery aging and economic performance in energy management. The energy management problem is formulated as a model predictive controller (MPC). Simulation results demonstrate that the proposed control scheme achieves 96%-98% of the optimal performance given perfect forecasts over a long-term horizon. Moreover, the rate of battery capacity loss can be reduced by 25% with negligible losses in economic performance, through an appropriate cost function formulation.

  1. Semiconductor nanowires for photovoltaic and photoelectrochemical energy conversion

    NASA Astrophysics Data System (ADS)

    Dasgupta, Neil P.; Yang, Peidong

    2014-06-01

    Semiconductor nanowires (NW) possess several beneficial properties for efficient conversion of solar energy into electricity and chemical energy. Due to their efficient absorption of light, short distances for minority carriers to travel, high surface-to-volume ratios, and the availability of scalable synthesis methods, they provide a pathway to address the low cost-to-power requirements for wide-scale adaptation of solar energy conversion technologies. Here we highlight recent progress in our group towards implementation of NW components as photovoltaic and photoelectrochemical energy conversion devices. An emphasis is placed on the unique properties of these one-dimensional (1D) structures, which enable the use of abundant, low-cost materials and improved energy conversion efficiency compared to bulk devices.

  2. Semiconductor nanowires for photovoltaic and photoelectrochemical energy conversion

    SciTech Connect

    Dasgupta, Neil; Yang, Peidong

    2013-01-23

    Semiconductor nanowires (NW) possess several beneficial properties for efficient conversion of solar energy into electricity and chemical energy. Due to their efficient absorption of light, short distances for minority carriers to travel, high surface-to-volume ratios, and the availability of scalable synthesis methods, they provide a pathway to address the low cost-to-power requirements for wide-scale adaptation of solar energy conversion technologies. Here we highlight recent progress in our group towards implementation of NW components as photovoltaic and photoelectrochemical energy conversion devices. An emphasis is placed on the unique properties of these one-dimensional (1D) structures, which enable the use of abundant, low-cost materials and improved energy conversion efficiency compared to bulk devices.

  3. Review of Photovoltaic Energy Production Using Thin Film Modules

    NASA Astrophysics Data System (ADS)

    Gessert, Timothy

    2011-04-01

    It is now widely accepted that thin-film photovoltaic (PV) devices will be important contributors of new US electricity generation. The annual production of PV devices needed to meet conservative U.S. Department of Energy goals for 2050 represents ˜100 square miles of active module area (20 GW), or ˜200 times the total area of photovoltaic modules installed in the US by 2004. However, if the rate of growth observed in PV module production for the past eight years continues, 100 square miles of annual US PV production could be achieved as early as 2018. Further, the amount PV installed by 2036 could generate the entire 2004 US Total Energy Consumption (˜100 Quadrillion BTU's, i.e., the combined energy consumed in the US from petroleum, coal, natural gas, nuclear, and all renewable sources). Regardless of what assumptions are made, PV represents a significant future market for related materials and technologies. This talk will discuss thin-film PV devices within the context of the major PV technologies in production today, and indicate areas where improved material and device understanding would be beneficial. This work was performed with the support of US Department of Energy Contract No. DE-AC36-08-GO28308. This abstract is subject to government rights.

  4. Future of photovoltaic energy conversion in developing countries

    SciTech Connect

    Hogan, S.

    1980-04-01

    Recent studies reveal that photovoltaic energy conversion will be economically viable for usage in developing countries. An overview of programs designed to lower the costs of such conversion systems is presented. Government goals are reviewed, as well as application projects relative to rural usage. A summary of the state-of-the-art in both advanced research and commercially available technology is presented. It is concluded that with the range of the work being done, such systems will be viable for many rural applications within 5 years.

  5. Organic photovoltaics

    NASA Astrophysics Data System (ADS)

    Leo, Karl

    2016-08-01

    Organic photovoltaics are on the verge of revolutionizing building-integrated photovoltaics. For other applications, however, several basic open scientific questions need answering to, in particular, further improve energy-conversion efficiency and lifetime.

  6. Electro-mechanical energy conversion system having a permanent magnet machine with stator, resonant transfer link and energy converter controls

    DOEpatents

    Skeist, S. Merrill; Baker, Richard H.

    2006-01-10

    An electro-mechanical energy conversion system coupled between an energy source and an energy load comprising an energy converter device including a permanent magnet induction machine coupled between the energy source and the energy load to convert the energy from the energy source and to transfer the converted energy to the energy load and an energy transfer multiplexer to control the flow of power or energy through the permanent magnetic induction machine.

  7. PowerSphere: A Novel Photovoltaic Cavity Converter Using Low Bandgap TPV Cells for Efficient Conversion of High Power Laser Beams to Electricity

    NASA Astrophysics Data System (ADS)

    Ortabasi, Ugur; Friedman, Herbert W.

    2004-11-01

    PowerSphere is a variant of the recently developed Photovoltaic Cavity Converter (PVCC) for High Concentration Photovoltaic applications. Both systems share the benefit of photon recycling in a cavity and have therefore the potential to convert high-density radiant power to electricity at unprecedented efficiencies. Unlike PVCC that is optimized for the full content of the solar spectrum, the PowerSphere is designed to convert the monochromatic beam of a laser efficiently to electricity. The PowerSphere concept introduced here greatly benefits from recent advances in the area of high power, near-IR lasers and advanced bandgap engineering involving `tunable' III-V cells operating in the same range of the spectrum. Given this new scenario the spectral response of such cells can be perfectly tuned to the frequency of a high power laser to achieve conversion efficiencies in excess of 60%. Other key phenomena that allow achieving such high conversion rates are described in the main text of this paper. PowerSphere concept when fully developed can greatly contribute to the advancement of Laser Power Beaming technology for terrestrial, near-space and space applications. The paper explores the performance potential of Laser Power Beaming (LPB) systems using a PowerSphere as a receiver and discusses some of the critical issues that require further studies in this promising area of `Wireless Power Transmission'.

  8. The TELEC - A plasma type of direct energy converter. [Thermo-Electronic Laser Energy Converter for electric power generation

    NASA Technical Reports Server (NTRS)

    Britt, E. J.

    1978-01-01

    The Thermo-Electronic Laser Energy Converter (TELEC) is a high-power density plasma device designed to convert a 10.6-micron CO2 laser beam into electric power. Electromagnetic radiation is absorbed in plasma electrons, creating a high-electron temperature. Energetic electrons diffuse from the plasma and strike two electrodes having different areas. The larger electrode collects more electrons and there is a net transport of current. An electromagnetic field is generated in the external circuit. A computer program has been designed to analyze TELEC performance allowing parametric variation for optimization. Values are presented for TELEC performance as a function of cesium pressure and for current density and efficiency as a function of output voltage. Efficiency is shown to increase with pressure, reaching a maximum over 45%.

  9. Reference Model 6 (RM6): Oscillating Wave Energy Converter.

    SciTech Connect

    Bull, Diana L; Smith, Chris; Jenne, Dale Scott; Jacob, Paul; Copping, Andrea; Willits, Steve; Fontaine, Arnold; Brefort, Dorian; Gordon, Margaret Ellen; Copeland, Robert; Jepsen, Richard Alan

    2014-10-01

    This report is an addendum to SAND2013-9040: Methodology for Design and Economic Analysis of Marine Energy Conversion (MEC) Technologies. This report describes an Oscillating Water Column Wave Energy Converter reference model design in a complementary manner to Reference Models 1-4 contained in the above report. In this report, a conceptual design for an Oscillating Water Column Wave Energy Converter (WEC) device appropriate for the modeled reference resource site was identified, and a detailed backward bent duct buoy (BBDB) device design was developed using a combination of numerical modeling tools and scaled physical models. Our team used the methodology in SAND2013-9040 for the economic analysis that included costs for designing, manufacturing, deploying, and operating commercial-scale MEC arrays, up to 100 devices. The methodology was applied to identify key cost drivers and to estimate levelized cost of energy (LCOE) for this RM6 Oscillating Water Column device in dollars per kilowatt-hour ($/kWh). Although many costs were difficult to estimate at this time due to the lack of operational experience, the main contribution of this work was to disseminate a detailed set of methodologies and models that allow for an initial cost analysis of this emerging technology. This project is sponsored by the U.S. Department of Energy's (DOE) Wind and Water Power Technologies Program Office (WWPTO), within the Office of Energy Efficiency & Renewable Energy (EERE). Sandia National Laboratories, the lead in this effort, collaborated with partners from National Laboratories, industry, and universities to design and test this reference model.

  10. Electricity from Sunlight: The Future of Photovoltaics. Worldwatch Paper 52.

    ERIC Educational Resources Information Center

    Flavin, Christopher

    Solar photovoltaic cells have been called the ultimate energy technology, environmentally benign and without moving parts, solar cells directly convert sunlight into electricity. Photovoltaic energy conversion is fundamentally different from all other forms of electricity generation. Without turbines, generators or other mechanical equipment, it…

  11. Low Head, Vortex Induced Vibrations River Energy Converter

    SciTech Connect

    Bernitsas, Michael B.; Dritz, Tad

    2006-06-30

    Vortex Induced Vibrations Aquatic Clean Energy (VIVACE) is a novel, demonstrated approach to extracting energy from water currents. This invention is based on a phenomenon called Vortex Induced Vibrations (VIV), which was first observed by Leonardo da Vinci in 1504AD. He called it ‘Aeolian Tones.’ For decades, engineers have attempted to prevent this type of vibration from damaging structures, such as offshore platforms, nuclear fuel rods, cables, buildings, and bridges. The underlying concept of the VIVACE Converter is the following: Strengthen rather than spoil vortex shedding; enhance rather than suppress VIV; harness rather than mitigate VIV energy. By maximizing and utilizing this unique phenomenon, VIVACE takes this “problem” and successfully transforms it into a valuable resource for mankind.

  12. Heterobarrier for converting hot-phonon energy to electric potential

    NASA Astrophysics Data System (ADS)

    Shin, Seungha; Melnick, Corey; Kaviany, Massoud

    2013-02-01

    We show that hot phonons emitted in energy conversion or resistive processes can be converted to electric potential in heterobarrier structures. Using phonon and electron interaction kinetics and self-consistent ensemble Monte Carlo, we find the favorable conditions for unassisted absorption of hot phonons and design graded heterobarriers for their direct conversion into electric energy. Tandem barriers with nearly optical-phonon height allow for substantial potential gain without current loss. We find that 19% of hot phonons can be harvested with an optimized GaAs/AlxGa1-xAs barrier structure over a range of current and electron densities, thus enhancing the overall energy conversion efficiency and reducing waste heat.

  13. PV Standards Work: Photovoltaic System and Component Certification, Test Facility Accreditation, and Solar Photovoltaic Energy Systems International Standards

    SciTech Connect

    Basso, T. S.; Chalmers, S.; Barikmo, H. O.

    2005-11-01

    This paper discusses efforts led by two companies (PowerMark Corporation and Sunset Technologies Inc.) to support both U.S. domestic and international photovoltaic (PV) system and component certification and test facility accreditation programs and the operation of the International Electrotechnical Commission (IEC) Technical Committee 82 (TC-82) Photovoltaic Energy Systems. International and national PV certification/accreditation programs are successfully facilitating entry of only the highest quality PV products into the marketplace. Standards also continue to be a cornerstone for assuring global PV product conformity assessment, reducing non-tariff trade barriers, and ultimately improving PV products while lowering cost.

  14. Identifying solar energy potentials and intensifying the climate-friendly use of photovoltaics within urban areas.

    NASA Astrophysics Data System (ADS)

    de Lange, N.

    2016-04-01

    Limited non-renewable fossil energy reserves and the essential ideas of sustainability have caused an increase in the demand for solar energy. The intensified use of renewable energy in Germany is primarily encouraged by the German renewable-energy-law. Solar panels mounted on roofs generate electricity using the energy radiated from the sun by taking advantage of the photovoltaic effect. However, not every roof is usable for power generation through solar energy. Therefore, web-based solar energy registers for multiple regions in Germany have been developed that provide detailed information on roofs suitable for carrying solar panels. The analyses are based on a digital object model derived from airborne laser scanning data of high accuracy and a fully automated technology to classify the points. First, roof points are separated according to their single roof sides and are converted into polygons. Then, exposure, slope, size of the roof, and particularly shading effects are computed to calculate the solar potential of each roof side. The web-GIS provides detailed information about the roof's suitability, such as the installable capacity and the expected generation of electricity. Thus, it helps house owners to calculate their investment and later revenues.

  15. Reference Model 5 (RM5): Oscillating Surge Wave Energy Converter

    SciTech Connect

    Yu, Y. H.; Jenne, D. S.; Thresher, R.; Copping, A.; Geerlofs, S.; Hanna, L. A.

    2015-01-01

    This report is an addendum to SAND2013-9040: Methodology for Design and Economic Analysis of Marine Energy Conversion (MEC) Technologies. This report describes an Oscillating Water Column Wave Energy Converter (OSWEC) reference model design in a complementary manner to Reference Models 1-4 contained in the above report. A conceptual design for a taut moored oscillating surge wave energy converter was developed. The design had an annual electrical power of 108 kilowatts (kW), rated power of 360 kW, and intended deployment at water depths between 50 m and 100 m. The study includes structural analysis, power output estimation, a hydraulic power conversion chain system, and mooring designs. The results were used to estimate device capital cost and annual operation and maintenance costs. The device performance and costs were used for the economic analysis, following the methodology presented in SAND2013-9040 that included costs for designing, manufacturing, deploying, and operating commercial-scale MEC arrays up to 100 devices. The levelized cost of energy estimated for the Reference Model 5 OSWEC, presented in this report, was for a single device and arrays of 10, 50, and 100 units, and it enabled the economic analysis to account for cost reductions associated with economies of scale. The baseline commercial levelized cost of energy estimate for the Reference Model 5 device in an array comprised of 10 units is $1.44/kilowatt-hour (kWh), and the value drops to approximately $0.69/kWh for an array of 100 units.

  16. High-efficiency grid-connected photovoltaic module integrated converter system with high-speed communication interfaces for small-scale distribution power generation

    SciTech Connect

    Choi, Woo-Young; Lai, Jih-Sheng

    2010-04-15

    This paper presents a high-efficiency grid-connected photovoltaic (PV) module integrated converter (MIC) system with reduced PV current variation. The proposed PV MIC system consists of a high-efficiency step-up DC-DC converter and a single-phase full-bridge DC-AC inverter. An active-clamping flyback converter with a voltage-doubler rectifier is proposed for the step-up DC-DC converter. The proposed step-up DC-DC converter reduces the switching losses by eliminating the reverse-recovery current of the output rectifying diodes. To reduce the PV current variation introduced by the grid-connected inverter, a PV current variation reduction method is also suggested. The suggested PV current variation reduction method reduces the PV current variation without any additional components. Moreover, for centralized power control of distributed PV MIC systems, a PV power control scheme with both a central control level and a local control level is presented. The central PV power control level controls the whole power production by sending out reference power signals to each individual PV MIC system. The proposed step-up DC-DC converter achieves a high-efficiency of 97.5% at 260 W output power to generate the DC-link voltage of 350 V from the PV voltage of 36.1 V. The PV MIC system including the DC-DC converter and the DC-AC inverter achieves a high-efficiency of 95% with the PV current ripple less than 3% variation of the rated PV current. (author)

  17. Analysis of Photovoltaic System Energy Performance Evaluation Method

    SciTech Connect

    Kurtz, S.; Newmiller, J.; Kimber, A.; Flottemesch, R.; Riley, E.; Dierauf, T.; McKee, J.; Krishnani, P.

    2013-11-01

    Documentation of the energy yield of a large photovoltaic (PV) system over a substantial period can be useful to measure a performance guarantee, as an assessment of the health of the system, for verification of a performance model to then be applied to a new system, or for a variety of other purposes. Although the measurement of this performance metric might appear to be straight forward, there are a number of subtleties associated with variations in weather and imperfect data collection that complicate the determination and data analysis. A performance assessment is most valuable when it is completed with a very low uncertainty and when the subtleties are systematically addressed, yet currently no standard exists to guide this process. This report summarizes a draft methodology for an Energy Performance Evaluation Method, the philosophy behind the draft method, and the lessons that were learned by implementing the method.

  18. Photovoltaics as a terrestrial energy source. Volume 1: An introduction

    NASA Technical Reports Server (NTRS)

    Smith, J. L.

    1980-01-01

    Photovoltaic (PV) systems were examined their potential for terrestrial application and future development. Photovoltaic technology, existing and potential photovoltaic applications, and the National Photovoltaics Program are reviewed. The competitive environment for this electrical source, affected by the presence or absence of utility supplied power is evaluated in term of systems prices. The roles of technological breakthroughs, directed research and technology development, learning curves, and commercial demonstrations in the National Program are discussed. The potential for photovoltaics to displace oil consumption is examined, as are the potential benefits of employing PV in either central-station or non-utility owned, small, distributed systems.

  19. Analysis of the economics of photovoltaic-diesel-battery energy systems for remote applications

    NASA Technical Reports Server (NTRS)

    Brainard, W. A.

    1983-01-01

    Computer simulations were conducted to analyze the performance and operating cost of a photovoltaic energy source combined with a diesel generator system and battery storage. The simulations were based on the load demand profiles used for the design of an all photovoltaic energy system installed in the remote Papago Indian Village of Schuchuli, Arizona. Twenty year simulations were run using solar insolation data from Phoenix SOLMET tapes. Total energy produced, energy consumed, operation and maintenance costs were calculated. The life cycle and levelized energy costs were determined for a variety of system configurations (i.e., varying amounts of photovoltaic array and battery storage).

  20. Duke Energy Photovoltaic Integration Study: Carolinas Service Areas

    SciTech Connect

    Lu, Shuai; Samaan, Nader A.; Meng, Da; Chassin, Forrest S.; Zhang, Yu; Vyakaranam, Bharat; Warwick, William M.; Fuller, Jason C.; Diao, Ruisheng; Nguyen, Tony B.; Jin, Chunlian

    2014-03-01

    Solar energy collected using photovoltaic (PV) technology is a clean and renewable energy source that offers multiple benefits to the electric utility industry and its customers, such as cost predictability, reduced emissions, and loss reduction by distributed installations. Renewable energy goals established in North Carolina Senate Bill 3 (SB3), in combination with the state tax credit and decreases in the cost of energy from PV panels, have resulted in rapid solar power penetration within the Carolinas services areas of Duke Energy. Continued decreases in PV prices are expected to lead to greater PV penetration rates than currently required in SB3. Despite the potential benefits, significant penetration of PV energy is of concern to the utility industry because of its impact on operating reliability and integration cost to customers, and equally important, how any additional costs may be allocated to different customer groups. Some of these impacts might become limiting factors for PV energy, especially growing distributed generation installed at customer sites. Recognizing the importance of renewable energy developments for a sustainable energy future and economic growth, Duke Energy has commissioned this study to simulate the effects of high-PV penetration rates and to initiate the process of quantifying the impacts. The objective of the study is to inform resource plans, guide operation improvements, and drive infrastructure investments for a steady and smooth transition to a new energy mix that provides optimal values to customers. The study team consists of experts from Pacific Northwest National Laboratory (PNNL), Power Costs, Inc. (PCI), Clean Power Research (CPR), Alstom Grid, and Duke Energy. PNNL, PCI, and CPR performed the study on generation impacts; Duke Energy modeled the transmission cases; and distribution simulations were conducted by Alstom Grid. PNNL analyzed the results from each work stream and produced the report.

  1. Standing wave tube electro active polymer wave energy converter

    NASA Astrophysics Data System (ADS)

    Jean, Philippe; Wattez, Ambroise; Ardoise, Guillaume; Melis, C.; Van Kessel, R.; Fourmon, A.; Barrabino, E.; Heemskerk, J.; Queau, J. P.

    2012-04-01

    Over the past 4 years SBM has developed a revolutionary Wave Energy Converter (WEC): the S3. Floating under the ocean surface, the S3 amplifies pressure waves similarly to a Ruben's tube. Only made of elastomers, the system is entirely flexible, environmentally friendly and silent. Thanks to a multimodal resonant behavior, the S3 is capable of efficiently harvesting wave energy from a wide range of wave periods, naturally smoothing the irregularities of ocean wave amplitudes and periods. In the S3 system, Electro Active Polymer (EAP) generators are distributed along an elastomeric tube over several wave lengths, they convert wave induced deformations directly into electricity. The output is high voltage multiphase Direct Current with low ripple. Unlike other conventional WECs, the S3 requires no maintenance of moving parts. The conception and operating principle will eventually lead to a reduction of both CAPEX and OPEX. By integrating EAP generators into a small scale S3, SBM achieved a world first: direct conversion of wave energy in electricity with a moored flexible submerged EAP WEC in a wave tank test. Through an extensive testing program on large scale EAP generators, SBM identified challenges in scaling up to a utility grid device. French Government supports the consortium consisting of SBM, IFREMER and ECN in their efforts to deploy a full scale prototype at the SEMREV test center in France at the horizon 2014-2015. SBM will be seeking strategic as well as financial partners to unleash the true potentials of the S3 Standing Wave Tube Electro Active Polymer WEC.

  2. U.S. Department of Energy photovoltaic energy program contract summary, fiscal year 1999

    SciTech Connect

    Surek, T.; Hansen, A.

    2000-02-17

    This report summarizes the in-house and subcontracted research and development (R and D) activities under the National Center for Photovoltaics (NCPV) and US Department of Energy (DOE) National Photovoltaics Program from October 1, 1998, through September 30, 1999 (FY 1999). The mission of the DOE National Photovoltaics Program is to make PV a significant part of the domestic economy as an industry and an energy resource. The two primary goals of the national program are to (1) maintain the US industry's world leadership in research and technology development and (2) help the US industry remain a major, profitable force in the world market. The NCPV is part of the National PV Program and provides leadership and support to the national program toward achieving its mission and goals.

  3. An update on the Department of Energy's photovoltaic program

    NASA Astrophysics Data System (ADS)

    Benner, John P.; Fitzgerald, Mark

    1994-09-01

    Funding for the terrestrial photovoltaic's program is $78 million in 1994. This is more than double the minimum level reached in 1989 and runs counter to the general trend of decreasing budgets for Department of Energy (DOE) programs. During the past five years, the program has expanded its mission from research and development to also address manufacturing technology and commercialization assistance. These new activities are directed toward revitalizing the market to reinstate the rapid rate of sales growth needed to attract investment. The program is approaching balance among efforts in each of the three areas. This translates to a reduction in some of the R & D activities of most relevance to the space power community. On the other hand, some of the advancements in manufacturing may finally bring thin-film technologies to reality for space arrays. This talk will describe the status and direction of DOE program with an eye toward highlighting its impact on technology of interest for space.

  4. The Redox flow system for solar photovoltaic energy storage

    NASA Technical Reports Server (NTRS)

    Odonnell, P.; Gahn, R. F.

    1976-01-01

    A new method of storage was applied to a solar photovoltaic system. The storage method is a redox flow system which utilizes the oxidation-reduction capability of two soluble electrochemical redox couples for its storage capacity. The particular variant described separates the charging and discharging function of the system such that the electrochemical couples are simultaneously charged and discharged in separate parts of the system. The solar array had 12 solar cells; wired in order to give a range of voltages and currents. The system stored the solar energy so that a load could be run continually day and night. The main advantages of the redox system are that it can accept a charge in the low voltage range and produce a relatively constant output regardless of solar activity.

  5. An update on the Department of Energy's photovoltaic program

    NASA Technical Reports Server (NTRS)

    Benner, John P.; Fitzgerald, Mark

    1994-01-01

    Funding for the terrestrial photovoltaic's program is $78 million in 1994. This is more than double the minimum level reached in 1989 and runs counter to the general trend of decreasing budgets for Department of Energy (DOE) programs. During the past five years, the program has expanded its mission from research and development to also address manufacturing technology and commercialization assistance. These new activities are directed toward revitalizing the market to reinstate the rapid rate of sales growth needed to attract investment. The program is approaching balance among efforts in each of the three areas. This translates to a reduction in some of the R & D activities of most relevance to the space power community. On the other hand, some of the advancements in manufacturing may finally bring thin-film technologies to reality for space arrays. This talk will describe the status and direction of DOE program with an eye toward highlighting its impact on technology of interest for space.

  6. Photovoltaics as a terrestrial energy source. Volume 2: System value

    NASA Technical Reports Server (NTRS)

    Smith, J. L.

    1980-01-01

    Assumptions and techniques employed by the electric utility industry and other electricity planners to make estimates of the future value of photovoltaic (PV) systems interconnected with U.S. electric utilities were examined. Existing estimates of PV value and their interpretation and limitations are discussed. PV value is defined as the marginal private savings accruing to potential PV owners. For utility-owned PV systems, these values are shown to be the after-tax savings in conventional fuel and capacity displaced by the PV output. For non-utility-owned (distributed) systems, the utility's savings in fuel and capacity must first be translated through the electric rate structure (prices) to the potential PV system owner. Base-case estimates of the average value of PV systems to U.S. utilities are presented. The relationship of these results to the PV Program price goals and current energy policy is discussed; the usefulness of PV output quantity goals is also reviewed.

  7. Energy and environmental analysis of a linear concentrating photovoltaic system

    NASA Astrophysics Data System (ADS)

    Kerzmann, Tony

    The world is facing an imminent energy supply crisis. In order to sustain and increase our energy supply in an environmentally-conscious manner, it is necessary to advance renewable technologies. Despite this urgency, however, it is paramount to consider the larger environmental effects associated with using renewable energy resources. This research is meant to better understand linear concentrating photovoltaics (LCPVs) from an engineering and environmental standpoint. In order to analyze the LCPV system, a simulation and life cycle assessment (LCA) were developed. The LCPV system serves two major purposes: it produces electricity, and waste heat is collected for heating use. There are three parts to the LCPV simulation. The first part simulates the multijunction cell output so as to calculate the temperature-dependent electricity generation. The second part simulates the cell cooling and waste heat recovery system using a model consisting of heat transfer and fluid flow equations. The waste heat recovery in the LCPV system was linked to a hot water storage system, which was also modeled. Coupling the waste heat recovery simulation and the hot water storage system gives an overall integrated system that is useful for system design, optimization, and acts as a stepping stone for future multijunction cell Photovoltaic/Thermal (PV/T) systems. Finally, all of the LCPV system components were coded in Engineering Equation Solver (EES) and were used in an energy analysis under actual weather and solar conditions for the Phoenix, AZ, region. The life cycle assessment for the LCPV system allowed for an environmental analysis of the system where areas of the highest environmental impact were pinpointed. While conducting the LCA research, each component of the system was analyzed from a resource extraction, production, and use standpoint. The collective production processes of each LCPV system component were gathered into a single inventory of materials and energy flows

  8. Modular DC-DC converter system for energy harvesting with EAPs

    NASA Astrophysics Data System (ADS)

    Eitzen, L.; Graf, C.; Maas, J.

    2013-04-01

    Energy harvesting with EAPs requires an energy-efficient power electronics providing a bidirectional energy transfer and operating voltages of up to several kilovolts. A possibility to achieve a high energy-efficiency for high voltage conversion is the use of a modular converter system consisting of several bidirectional converter modules, which are connected in series on the converter output side and in parallel at the input side. Since each converter stage provides only a part of the overall converter output voltage, the converter module output voltages can effectively be reduced by choosing the number of cascaded converter modules appropriately. This allows the use of standard semiconductor switches with superior electrical characteristics compared to high voltage semiconductors, enabling a high energy-efficiency and smaller passive components. Since EAP devices exhibit a mainly capacitive behavior and a limitation of the operating current is required for electrode protection, the utilized converter structure/topology has to be operated as a controllable current source on the lowest control level, which is achieved by operating the converter modules of the modular converter system with a subordinate closed-looped current control scheme. In order to avoid voltage unbalances among the single converter modules, a method for voltage balancing is presented. For validation, experimental results of a realized bidirectional flyback converter prototype are presented and discussed.

  9. Inverted organic photovoltaic cells.

    PubMed

    Wang, Kai; Liu, Chang; Meng, Tianyu; Yi, Chao; Gong, Xiong

    2016-05-21

    The advance in lifestyle, modern industrialization and future technological revolution are always at high expense of energy consumption. Unfortunately, there exist serious issues such as limited storage, high cost and toxic contamination in conventional fossil fuel energy sources. Instead, solar energy represents a renewable, economic and green alternative in the future energy market. Among the photovoltaic technologies, organic photovoltaics (OPVs) demonstrate a cheap, flexible, clean and easy-processing way to convert solar energy into electricity. However, OPVs with a conventional device structure are still far away from industrialization mainly because of their short lifetime and the energy-intensive deposition of top metal electrode. To address the stability and cost issue simultaneously, an inverted device structure has been introduced into OPVs, bridging laboratory research with practical application. In this review, recent progress in device structures, working mechanisms, functions and advances of each component layer as well their correlations with the efficiency and stability of inverted OPVs are reviewed and illustrated. PMID:27087582

  10. Holographic lens spectrum splitting photovoltaic system for increased diffuse collection and annual energy yield

    NASA Astrophysics Data System (ADS)

    Vorndran, Shelby D.; Wu, Yuechen; Ayala, Silvana; Kostuk, Raymond K.

    2015-09-01

    Concentrating and spectrum splitting photovoltaic (PV) modules have a limited acceptance angle and thus suffer from optical loss under off-axis illumination. This loss manifests itself as a substantial reduction in energy yield in locations where a significant portion of insulation is diffuse. In this work, a spectrum splitting PV system is designed to efficiently collect and convert light in a range of illumination conditions. The system uses a holographic lens to concentrate shortwavelength light onto a smaller, more expensive indium gallium phosphide (InGaP) PV cell. The high efficiency PV cell near the axis is surrounded with silicon (Si), a less expensive material that collects a broader portion of the solar spectrum. Under direct illumination, the device achieves increased conversion efficiency from spectrum splitting. Under diffuse illumination, the device collects light with efficiency comparable to a flat-panel Si module. Design of the holographic lens is discussed. Optical efficiency and power output of the module under a range of illumination conditions from direct to diffuse are simulated with non-sequential raytracing software. Using direct and diffuse Typical Metrological Year (TMY3) irradiance measurements, annual energy yield of the module is calculated for several installation sites. Energy yield of the spectrum splitting module is compared to that of a full flat-panel Si reference module.

  11. A High Efficiency Boost Converter with MPPT Scheme for Low Voltage Thermoelectric Energy Harvesting

    NASA Astrophysics Data System (ADS)

    Guan, Mingjie; Wang, Kunpeng; Zhu, Qingyuan; Liao, Wei-Hsin

    2016-07-01

    Using thermoelectric elements to harvest energy from heat has been of great interest during the last decade. This paper presents a direct current-direct current (DC-DC) boost converter with a maximum power point tracking (MPPT) scheme for low input voltage thermoelectric energy harvesting applications. Zero current switch technique is applied in the proposed MPPT scheme. Theoretical analysis on the converter circuits is explored to derive the equations for parameters needed in the design of the boost converter. Simulations and experiments are carried out to verify the theoretical analysis and equations. A prototype of the designed converter is built using discrete components and a low-power microcontroller. The results show that the designed converter can achieve a high efficiency at low input voltage. The experimental efficiency of the designed converter is compared with a commercial converter solution. It is shown that the designed converter has a higher efficiency than the commercial solution in the considered voltage range.

  12. Realizing Efficient Energy Harvesting from Organic Photovoltaic Cells

    NASA Astrophysics Data System (ADS)

    Zou, Yunlong

    Organic photovoltaic cells (OPVs) are emerging field of research in renewable energy. The development of OPVs in recent years has made this technology viable for many niche applications. In order to realize widespread application however, the power conversion efficiency requires further improvement. The efficiency of an OPV depends on the short-circuit current density (JSC), open-circuit voltage (VOC) and fill factor (FF). For state-of-the-art devices, JSC is mostly optimized with the application of novel low-bandgap materials and a bulk heterojunction device architecture (internal quantum efficiency approaching 100%). The remaining limiting factors are the low VOC and FF. This work focuses on overcoming these bottlenecks for improved efficiency. Temperature dependent measurements of device performance are used to examine both charge transfer and exciton ionization process in OPVs. The results permit an improved understanding of the intrinsic limit for VOC in various device architectures and provide insight on device operation. Efforts have also been directed at engineering device architecture for optimized FF, realizing a very high efficiency of 8% for vapor deposited small molecule OPVs. With collaborators, new molecules with tailored desired energy levels are being designed for further improvements in efficiency. A new type of hybrid organic-inorganic perovskite material is also included in this study. By addressing processing issues and anomalous hysteresis effects, a very high efficiency of 19.1% is achieved. Moving forward, topics including engineering film crystallinity, exploring tandem architectures and understanding degradation mechanisms will further push OPVs toward broad commercialization.

  13. Photovoltaic Cavity Converter as a Means of Enhancing the Performance of State-of-the-Art Multijunction and Multibandgap Concentrator Systems

    NASA Astrophysics Data System (ADS)

    Ortabasi, Ugur; Waszczak, John P.; Allen, Steven L.

    2011-12-01

    In this paper we report the developmental status of a High Concentration Photovoltaic system that uses a Photovoltaic Cavity Converter (PVCC) as the receiver. The unique feature of the PVCC receiver is its ability to efficiently re-cycle (re-use) photons that are reflected from a multi-cell array located near the focus of a two-axis tracking, parabolic dish. The Introduction of "Photon Re-cycling" for high concentrations applications (CR≥500X) has far reaching impacts on the achievable system performances with the state-of-the-art MJ cells. The most distinctive feature of the PVCC is its potential of extending the realm of the present day 3j technology to 4-, 5- and 6-Bandgap concentrator systems. The paper summarizes the analytical studies that support the rational behind the PVCC concept. Preliminary field tests were conducted with a 1/36 downscaled, but high fidelity HCPV system to compare the "cavity" versus "non-cavity" modes of operation. The system power output improved by 55% (relative) in the case of the "cavity" mode at 82% Cavity Optical Efficiency (COE). We project that 90% COE is realistically achievable. At this COE level, the module conversion efficiency of a PVCC using resistivity optimized III-V cells can be as high as 45%, today. A 6-bandgap, photon re-cycling PVCC using the state-of the-art 3j technology can achieve the module conversion efficiency of 50% in the foreseeable future.

  14. Computational Analysis of Energy Pooling to Harvest Low-Energy Solar Energy in Organic Photovoltaic Devices

    NASA Astrophysics Data System (ADS)

    Lacount, Michael; Shaheen, Sean; Rumbles, Garry; van de Lagemaat, Jao; Hu, Nan; Ostrowski, Dave; Lusk, Mark

    2014-03-01

    Current photovoltaic energy conversions do not typically utilize low energy sunlight absorption, leaving large sections of the solar spectrum untapped. It is possible, though, to absorb such radiation, generating low-energy excitons, and then pool them to create higher energy excitons, which can result in an increase in efficiency. Calculation of the rates at which such upconversion processes occur requires an accounting of all possible molecular quantum electrodynamics (QED) pathways. There are two paths associated with the upconversion. The cooperative mechanism involves a three-body interaction in which low energy excitons are transferred sequentially onto an acceptor molecule. The accretive pathway, requires that an exciton transfer its energy to a second exciton that subsequently transfers its energy to the acceptor molecule. We have computationally modeled both types of molecular QED obtaining rates using a combination of DFT and many-body Green function theory. The simulation platform is exercised by considering upconversion events associated with material composed of a high energy absorbing core of hexabenzocoronene (HBC) and low energy absorbing arms of oligothiophene. In addition, we make estimates for all competing processes in order to judge the relative efficiencies of these two processes.

  15. Optimal geometry of an axisymmetric wave energy converter

    NASA Astrophysics Data System (ADS)

    Edwards, Emma; Yue, Dick K. P.; Vortical Flow Research Laboratory Team

    2015-11-01

    There have been a number of theoretical, experimental and pilot-scale studies on wave energy converters with varying shapes and designs, but due to the complex nature of wave-body hydrodynamics, as yet there is not one single three-dimensional shape that is agreed-upon to be optimal for wave power extraction. Our objective is to determine the optimal geometry to maximize power uptake over a spectrum of incident waves. As an initial investigation, we consider an axisymmetric floating wave power extraction device operating in heave. We assume linear wave conditions. The body geometry is described by smooth polynomial basis functions and is allowed to be completely general, subject to simple constraints. We consider a linear power uptake with a fixed damping coefficient (which could be optimized). For each frequency in the spectrum, hydrodynamic coefficients are calculated using a linear frequency-domain panel method. Then, for a specific incident wave spectrum, maximal extractable power is integrated over the entire spectrum. We will discuss the optimal geometry and associated maximum power for different geometrical constraints and wave conditions.

  16. Organic photovoltaics

    NASA Astrophysics Data System (ADS)

    Demming, Anna; Krebs, Frederik C.; Chen, Hongzheng

    2013-12-01

    Energy inflation, the constant encouragement to economize on energy consumption and the huge investments in developing alternative energy resources might seem to suggest that there is a global shortage of energy. Far from it, the energy the Sun beams on the Earth each hour is equivalent to a year's supply, even at our increasingly ravenous rate of global energy consumption [1]. But it's not what you have got it's what you do with it. Hence the intense focus on photovoltaic research to find more efficient ways to harness energy from the Sun. Recently much of this research has centred on organic solar cells since they offer simple, low-cost, light-weight and large-area flexible photovoltaic structures. This issue with guest editors Frederik C Krebs and Hongzheng Chen focuses on some of the developments at the frontier of organic photovoltaic technology. Improving the power conversion efficiency of organic photovoltaic systems, while maintaining the inherent material, economic and fabrication benefits, has absorbed a great deal of research attention in recent years. Here significant progress has been made with reports now of organic photovoltaic devices with efficiencies of around 10%. Yet operating effectively across the electromagnetic spectrum remains a challenge. 'The trend is towards engineering low bandgap polymers with a wide optical absorption range and efficient hole/electron transport materials, so that light harvesting in the red and infrared region is enhanced and as much light of the solar spectrum as possible can be converted into an electrical current', explains Mukundan Thelakkat and colleagues in Germany, the US and UK. In this special issue they report on how charge carrier mobility and morphology of the active blend layer in thin film organic solar cells correlate with device parameters [2]. The work contributes to a better understanding of the solar-cell characteristics of polymer:fullerene blends, which form the material basis for some of the most

  17. Energy Extraction from a Slider-Crank Wave Energy Converter under Irregular Wave Conditions

    SciTech Connect

    Sang, Yuanrui; Karayaka, H. Bora; Yan, Yanjun; Zhang, James Z.; Muljadi, Eduard; Yu, Yi-Hsiang

    2015-10-19

    A slider-crank wave energy converter (WEC) is a novel energy conversion device. It converts wave energy into electricity at a relatively high efficiency, and it features a simple structure. Past analysis on this particular WEC has been done under regular sinusoidal wave conditions, and suboptimal energy could be achieved. This paper presents the analysis of the system under irregular wave conditions; a time-domain hydrodynamics model is adopted and a rule-based control methodology is introduced to better serve the irregular wave conditions. Results from the simulations show that the performance of the system under irregular wave conditions is different from that under regular sinusoidal wave conditions, but a reasonable amount of energy can still be extracted.

  18. Manufacturing technologies for photovoltaics and possible means of their development in Russia (Review). Part 1: General approach to the development of photoelectric converters and basic silicon technologies

    NASA Astrophysics Data System (ADS)

    Tarasenko, A. B.; Popel', O. S.

    2015-11-01

    The state and key tendencies of the development of basic technologies for manufacture of photoelectric converters (PECs) in the world are considered, and their advantages and disadvantages are discussed. The first part of the review gives short information on the development of photovoltaics in the world and planes of the development of solar power plants in Russia. Total power of photoelectric plants operating in various countries in 2015 exceeded 150 GW and increased in the last ten years with a rate of approximately 50% per year. Russia made important state decisions on the support of the development of renewable power engineering and developed mechanisms, which were attractive for business, on the stimulation of building of the network of solar power plants with a total power to 1.5 GW in the country to 2020. At the same time, the rigid demands are made with respect to the localization of the production of components of these plants that opens new abilities for the development of the domestic production of photovoltaics manufacture. Data on the efficiency of PECs of various types that are attained in the leading laboratories of the world are given. Particular emphasis has been placed on the consideration of basic silicon technologies of PEC manufacture, which had the widest commercial application. The basic methods for production of polycrystalline silicon and making single-crystal and multicrystal silicon are described. Fundamentals of making techniques for plates, PECs, and photoelectric modules based on single-crystal and polycrystalline silicon are considered. The second part will be devoted to modifications of manufacturing techniques for photoelectric converters, enhancement methods for contact structures, and recommendations of authors with respect to the choice of prospective technologies for the expansion of PEC production in Russia. It will involve formulations and substantiations of the most promising lines of the development of photoelectric

  19. Experimental studies and computer simulation of the control of energy transfer using inductor-converter bridges

    SciTech Connect

    Hirano, M.; Kustom, R.L.

    1984-03-01

    An inductor-converter bridge (ICB) is a solid state DC-AC-DC power converter system for bidirectional, controllable, energy transfer between two coils. The ICB is suitable for supplying large pulsed power to such magnets as the superconducting equilibrium field coil of the proposed tokamak power reactors from another superconducting energy storage coil.

  20. Solar energy converter employing a fluorescent wavelength shifter

    SciTech Connect

    Garlick, G.F.J.

    1986-04-22

    A solar converter is described which consists of: (a) a zinc selenide fluorescent wavelength shifter including a fluorescent zinc selenide substrate having anti-reflecting coatings on opposite sides thereof and operative to convert predetermined wavelengths of solar radiation to radiation of different wavelengths for transmission to an adjacent solar cell, the fluorescent wavelength shifter having a response spectra extending between about 0.3 and 0.47 micrometers wavelength; (b) a gallium arsenide or aluminum gallium arsenide solar cell having a pn junction therein and an anti-reflective coating on one surface and further having a response spectra extending from approximately 0.47 micrometers to approximately 0.9 micrometers and operative to convert sunlight radiation of these wavelengths to output power; and (c) means for adhesively bonding one of the anti-reflectingly coated sides of the fluorescent wavelength shifter to the anti-reflective coating of the solar cell and for simultaneously providing good optical matching and transparency between these anti-reflecting coatings, whereby the pn junction of the solar cell converts radiation wavelengths within the fluorescence spectrum of the wavelength shifter to useful output power and thereby enhances and optimizes the solar conversion efficiency of the solar converter.

  1. Technical Study of a Standalone Photovoltaic-Wind Energy Based Hybrid Power Supply Systems for Island Electrification in Malaysia.

    PubMed

    Samrat, Nahidul Hoque; Ahmad, Norhafizan; Choudhury, Imtiaz Ahmed; Taha, Zahari

    2015-01-01

    Energy is one of the most important factors in the socioeconomic development of a country. In a developing country like Malaysia, the development of islands is mostly related to the availability of electric power. Power generated by renewable energy sources has recently become one of the most promising solutions for the electrification of islands and remote rural areas. But high dependency on weather conditions and the unpredictable nature of these renewable energy sources are the main drawbacks. To overcome this weakness, different green energy sources and power electronic converters need to be integrated with each other. This study presents a battery storage hybrid standalone photovoltaic-wind energy power supply system. In the proposed standalone hybrid system, a DC-DC buck-boost bidirectional converter controller is used to accumulates the surplus hybrid power in the battery bank and supplies this power to the load during the hybrid power shortage by maintaining the constant dc-link voltage. A three-phase voltage source inverter complex vector control scheme is used to control the load side voltage in terms of the voltage amplitude and frequency. Based on the simulation results obtained from MATLAB/Simulink, it has been found that the overall hybrid framework is capable of working under variable weather and load conditions. PMID:26121032

  2. Energy-efficient C-dump converters for switched reluctance motors

    SciTech Connect

    Mir, S.; Husain, I.; Elbuluk, M.E.

    1997-09-01

    Two energy-efficient converter topologies, derived from the conventional C-dump converter, are proposed for switched reluctance motor (SRM) drives. The proposed topologies overcome the limitations of the conventional C-dump converter, and could reduce the overall cost of the SRM drive. The voltage ratings of the dump capacitor and some of the switching devices in the proposed converters are reduced to the supply voltage (V{sub dc}) level compared to twice the supply voltage (2V{sub dc}) in the conventional C-dump converter. Also, the size of the dump inductor is considerably reduced. The converters have simple control requirements, and allow the motor phase current to freewheel during chopping mode. Simulation and experimental results of the converters are presented and discussed.

  3. Photovoltaic energy program in the State of Minas Gerais, Brazil

    SciTech Connect

    Diniz, A.S.A.C.; Prado, A.E.; Mendonca, M.S.C.C.; Almeida, F.Q.; Alvarenga, C.A.

    1997-12-31

    This paper describes the work done over the last years in the field of photovoltaic technology in the State of Minas Gerais, from its R and D to the Rural Electrification Program. The analysis of the global solar radiation data (over 5 kWh/m{sup 2}/day) has shown that photovoltaic systems can perform well all over the State, mainly in the north and Northeast regions of the state. The potential for the utilization of PV systems in Minas Gerais is large, mainly when considering the high number of consumers in rural remote areas that are not and cannot be supplied from CEMIG`s grid in the immediate future or in the long term. As a consequence of the demonstration projects, which have shown that photovoltaics can perform well and be cost effective in rural areas, a Rural Electrification Program was launched. To support it a training program has been set up.

  4. Characterization of encapsulant materials for photovoltaic solar energy conversion

    NASA Astrophysics Data System (ADS)

    Agroui, K.; Koll, B.; Collins, G.; Salama, M.; Hadj Arab, A.; Belghachi, A.; Doulache, N.; Khemici, M. W.

    2008-08-01

    The polyvinyl butyral (PVB) encapsulant material is being evaluated as a candidate for use in photovoltaic solar cells encapsulation process due to high stability against UV radiation and the high adhesive force to glass. This material is used for a long time in automotive technology, building integrated vitrification and security glazing. The long experience in this sector can direct be carried over to the photovoltaic industry. The purpose of this experimental investigation is to better understand the electrical properties and thermal stability of PVB based encapsulant material and their dependence on temperature will be presented. An overview of some main electrical and thermal properties of PVB is compared to EVA.

  5. Lithium Ion Cell Development for Photovoltaic Energy Storage Applications

    SciTech Connect

    Babinec, Susan

    2012-02-08

    The overall project goal is to reduce the cost of home and neighborhood photovoltaic storage systems by reducing the single largest cost component the energy storage cells. Solar power is accepted as an environmentally advantaged renewable power source. Its deployment in small communities and integrated into the grid, requires a safe, reliable and low cost energy storage system. The incumbent technology of lead acid cells is large, toxic to produce and dispose of, and offer limited life even with significant maintenance. The ideal PV storage battery would have the safety and low cost of lead acid but the performance of lithium ion chemistry. Present lithium ion batteries have the desired performance but cost and safety remain the two key implementation barriers. The purpose of this project is to develop new lithium ion cells that can meet PVES cost and safety requirements using A123Systems phosphate-based cathode chemistries in commercial PHEV cell formats. The cost target is a cell design for a home or neighborhood scale at <$25/kWh. This DOE program is the continuation and expansion of an initial MPSC (Michigan Public Service Commission) program towards this goal. This program further pushes the initial limits of some aspects of the original program even lower cost anode and cathode actives implemented at even higher electrode loadings, and as well explores new avenues of cost reduction via new materials specifically our higher voltage cathode. The challenge in our materials development is to achieve parity in the performance metrics of cycle life and high temperature storage, and to produce quality materials at the production scale. Our new cathode material, M1X, has a higher voltage and so requires electrolyte reformulation to meet the high temperature storage requirements. The challenge of thick electrode systems is to maintain adequate adhesion and cycle life. The composite separator has been proven in systems having standard loading electrodes; the challenge

  6. Full wave dc-to-dc converter using energy storage transformers

    NASA Technical Reports Server (NTRS)

    Moore, E. T.; Wilson, T. G.

    1969-01-01

    Full wave dc-to-dc converter, for an ion thrustor, uses energy storage transformers to provide a method of dc-to-dc conversion and regulation. The converter has a high degree of physical simplicity, is lightweight and has high efficiency.

  7. Model Predictive Control techniques with application to photovoltaic, DC Microgrid, and a multi-sourced hybrid energy system

    NASA Astrophysics Data System (ADS)

    Shadmand, Mohammad Bagher

    Renewable energy sources continue to gain popularity. However, two major limitations exist that prevent widespread adoption: availability and variability of the electricity generated and the cost of the equipment. The focus of this dissertation is Model Predictive Control (MPC) for optimal sized photovoltaic (PV), DC Microgrid, and multi-sourced hybrid energy systems. The main considered applications are: maximum power point tracking (MPPT) by MPC, droop predictive control of DC microgrid, MPC of grid-interaction inverter, MPC of a capacitor-less VAR compensator based on matrix converter (MC). This dissertation firstly investigates a multi-objective optimization technique for a hybrid distribution system. The variability of a high-penetration PV scenario is also studied when incorporated into the microgrid concept. Emerging (PV) technologies have enabled the creation of contoured and conformal PV surfaces; the effect of using non-planar PV modules on variability is also analyzed. The proposed predictive control to achieve maximum power point for isolated and grid-tied PV systems speeds up the control loop since it predicts error before the switching signal is applied to the converter. The low conversion efficiency of PV cells means we want to ensure always operating at maximum possible power point to make the system economical. Thus the proposed MPPT technique can capture more energy compared to the conventional MPPT techniques from same amount of installed solar panel. Because of the MPPT requirement, the output voltage of the converter may vary. Therefore a droop control is needed to feed multiple arrays of photovoltaic systems to a DC bus in microgrid community. Development of a droop control technique by means of predictive control is another application of this dissertation. Reactive power, denoted as Volt Ampere Reactive (VAR), has several undesirable consequences on AC power system network such as reduction in power transfer capability and increase in

  8. 205 kW Photovoltaic (PV) System Installed on the U.S. Department of Energy's Forrestal Building

    SciTech Connect

    2009-01-18

    Fact sheet on the installation of a photovoltaic system providing renewable energy for the U.S. Department of Energy and providing leadership for meeting Federal goals in the use of renewable energy technologies.

  9. 1994 IEEE first world conference on photovoltaic energy conversion: Conference record of the twenty-fourth IEEE photovoltaic specialists conference -- 1994. Volume 2

    SciTech Connect

    1994-12-31

    This volume contains the proceedings of the 1994 IEEE First World Conference on Photovoltaic Energy Conversion and conference record of the Twenty Fourth IEEE Photovoltaic Specialists Conference of 1994. The topics of the papers include research reports on advanced devices; results of pilot commercialization projects; financing, installing and operating photovoltaic power generating systems; and space photovoltaic device development and system applications. The papers are divided into the following sections: Silicon cells and materials; Si material growth and characterization; Si device and process modeling; Single crystal and high efficiency Si devices; Multicrystalline and thin-layer Si devices; Si defect and impurity effects in growth and processing; Si crystal growth and Si device modeling; Crystalline Si devices; Impurities and defects in crystalline Si and thin layer devices; Multijunction cells; Multijunction devices; Space systems; Space solar cells; National program economics and technology; and National programs status and prospects. All papers have been processed separately for inclusion on the data base.

  10. Current challenges in organic photovoltaic solar energy conversion.

    PubMed

    Schlenker, Cody W; Thompson, Mark E

    2012-01-01

    Over the last 10 years, significant interest in utilizing conjugated organic molecules for solid-state solar to electric conversion has produced rapid improvement in device efficiencies. Organic photovoltaic (OPV) devices are attractive for their compatibility with low-cost processing techniques and thin-film applicability to flexible and conformal applications. However, many of the processes that lead to power losses in these systems still remain poorly understood, posing a significant challenge for the future efficiency improvements required to make these devices an attractive solar technology. While semiconductor band models have been employed to describe OPV operation, a more appropriate molecular picture of the pertinent processes is beginning to emerge. This chapter presents mechanisms of OPV device operation, based on the bound molecular nature of the involved transient species. With the intention to underscore the importance of considering both thermodynamic and kinetic factors, recent progress in elucidating molecular characteristics that dictate photovoltage losses in heterojunction organic photovoltaics is also discussed. PMID:21837556

  11. Integrated photovoltaic-thermal solar energy conversion systems

    NASA Technical Reports Server (NTRS)

    Samara, G. A.

    1975-01-01

    A combined photovoltaic/thermal collector has been built and is now being tested. Initial tests have concentrated on evaluating the thermal efficiency of the collector before and after the silicon cells are mounted. With likely improvements in bonding between cells and receiver and in the absorptivity of the cells, thermal efficiencies greater than 50% can be expected for the combined receiver operating at 100 C.

  12. Integration of plug-in hybrid electric vehicles (PHEV) with grid connected residential photovoltaic energy systems

    NASA Astrophysics Data System (ADS)

    Nagarajan, Adarsh; Shireen, Wajiha

    2013-06-01

    This paper proposes an approach for integrating Plug-In Hybrid Electric Vehicles (PHEV) to an existing residential photovoltaic system, to control and optimize the power consumption of residential load. Control involves determining the source from which residential load will be catered, where as optimization of power flow reduces the stress on the grid. The system built to achieve the goal is a combination of the existing residential photovoltaic system, PHEV, Power Conditioning Unit (PCU), and a controller. The PCU involves two DC-DC Boost Converters and an inverter. This paper emphasizes on developing the controller logic and its implementation in order to accommodate the flexibility and benefits of the proposed integrated system. The proposed controller logic has been simulated using MATLAB SIMULINK and further implemented using Digital Signal Processor (DSP) microcontroller, TMS320F28035, from Texas Instruments

  13. Qualitative model of a plasma photoelectric converter

    NASA Astrophysics Data System (ADS)

    Gorbunov, N. A.; Flamant, G.

    2009-01-01

    A converter of focused optical radiation into electric current is considered on the basis of the photovoltaic effect in plasmas. The converter model is based on analysis of asymmetric spatial distributions of charge particle number density and ambipolar potential in the photoplasma produced by external optical radiation focused in a heat pipe filled with a mixture of alkali vapor and a heavy inert gas. Energy balance in the plasma photoelectric converter is analyzed. The conditions in which the external radiation energy is effectively absorbed in the converter are indicated. The plasma parameters for which the energy of absorbed optical radiation is mainly spent on sustaining the ambipolar field in the plasma are determined. It is shown that the plasma photoelectric converter makes it possible to attain a high conversion efficiency for focused solar radiation.

  14. First-order irreversible thermodynamic approach to a nonsteady RLC circuit as an energy converter

    NASA Astrophysics Data System (ADS)

    Valencia, G.; Arias, L. A.

    2015-01-01

    In this work we show a RLC-circuit as energy converter within the context of first-order irreversible thermodynamics (FOIT). For our analysis, we propose an isothermic model with transient elements and passive elements. With the help of the dynamic equations, the Kirchhoff equations, we found the generalized fluxes and forces of the circuit, the equation system shows symmetry of the cross terms, this property is characteristic of the steady state linear systems, but in this case phenomenological coefficients are function of time. Then, we can use these relations, similar to the linear Onsager relations, to construct the characteristic functions of the RLC energy converter: the power output, efficiency, dissipation and ecological function, and study its energetic performance. The study of performance of the converter is based on two parameters, the coupling parameter and the "forces ratio" parameter, in this case as functions of time. We find that the behavior of the non-steady state converter is similar to the behavior of steady state energy converter. We will explain the linear and symmetric behavior of the converter in the frequencies space rather than in the time space. Finally, we establish optimal operation regimes of economic degree of coupling for this energy converter.

  15. U.S. Department of Energy Photovoltaic Energy Program Contract Summary: Fiscal Year 2000

    SciTech Connect

    Surek, T.

    2001-02-21

    This report summarizes the in-house and subcontracted research and development (R and D) activities under the National Center for Photovoltaics (NCPV) and U.S. Department of Energy (DOE) National Photovoltaics Program from October 1, 1999, through September 30, 2000 (FY 2000). The mission of the DOE National Photovoltaics Program is to make PV a significant part of the domestic economy-as an industry and an energy resource. The two primary goals of the national program are to (1) maintain the U.S. industry's world leadership in research and technology development and (2) help the U.S. industry remain a major, profitable force in the world market. The NCPV is part of the National PV Program and provides leadership and support to the national program toward achieving its mission and goals. This Contract Summary for fiscal year (FY) 2000 documents some 179 research projects supported by the PV Program, performed by 107 organizations in 32 states, including 69 projects performed by universities and 60 projects performed by our industry partners. Of the total FY 2000 PV Program budget of $65.9 million, the industry and university research efforts received $36.9 million, or nearly 56%. And, of this amount, more than 93% was for contractors selected on a competitive basis. Much of the funding to industry was matched by industry cost-sharing. Each individual effort described in this summary represents another step toward improving PV manufacturing, performance, cost, and applications, and another step toward accomplishing the DOE PV Program's overall mission.

  16. Photovoltaic Performance and Reliability Database: A Gateway to Experimental Data Monitoring Projects for PV at the Florida Solar Energy Center

    DOE Data Explorer

    This site is the gateway to experimental data monitoring projects for photovoltaic (PV) at the Florida Solar Energy Center. The website and the database were designed to facilitate and standardize the processes for archiving, analyzing and accessing data collected from dozens of operational PV systems and test facilities monitored by FSEC's Photovoltaics and Distributed Generation Division. [copied from http://www.fsec.ucf.edu/en/research/photovoltaics/data_monitoring/index.htm

  17. Thermal to electrical energy converter based on black Si

    NASA Astrophysics Data System (ADS)

    Nishijima, Y.; Balčytis, A.; Komatsu, R.; Yamamura, T.; Seniutinas, G.; Wong, B. T.; Juodkazis, S.

    2015-03-01

    Photo-thermal - to - electrical converter is demonstrated by using a commercial Peltier Bi-Te element with a hot contact made out of nanotextured Si (black-Si). Black-Si with colloidal Au nanoparticles is shown to further increase the efficiency of thermal-to-electrical conversion. Peculiarities of heat harvesting using black-Si with plasmonic Au nanoparticles at different gold densities are analyzed. Solar radiation absorption and electric field enhancement in plain and Au nanoparticle decorated black-Si was simulated using finite difference time domain (FDTD) method. Thermal conduction in nanotextured black-Si was explained using phonon Monte-Carlo simulations at the nanoscale. Strategies for creating larger thermal gradient on Peltier element using nanotextured light absorbers is discussed.

  18. Photovoltaic test and demonstration project. [residential energy program

    NASA Technical Reports Server (NTRS)

    Forestieri, A. F.; Brandhorst, H. W., Jr.; Deyo, J. N.

    1976-01-01

    The considered project consists of three subprojects related to applications, device performance and diagnostics, and endurance testing. The objectives of the applications subproject include the determination of the operating characteristics for a variety of photovoltaic conversion systems. A system test facility is being constructed in this connection and a prototype residence experiment is to be conducted. Market demand for solar cells is to be stimulated by demonstrating suitability of solar cells for specific near-term applications. Activities conducted in connection with device performance studies and diagnostics are also discussed along with developments in the area of endurance testing.

  19. Instrumentation for Monitoring around Marine Renewable Energy Converters: Workshop Final Report

    SciTech Connect

    Polagye, B. L.; Copping, A. E.; Brown-Saracino, J.; Suryan, R.; Kramer, S.; Smith, C.

    2014-01-14

    To better understand the state of instrumentation and capabilities for monitoring around marine energy converters, the U.S. Department of Energy directed Pacific Northwest National Laboratory and the Northwest National Marine Renewable Energy Center at the University of Washington to convene an invitation-only workshop of experts from around the world to address instrumentation needs.

  20. Workshop proceedings: Photovoltaic conversion of solar energy for terrestrial applications. Volume 2: Invited papers

    NASA Technical Reports Server (NTRS)

    1973-01-01

    A photovoltaic device development plan is reported that considers technological as well as economical aspects of single crystal silicon, polycrystal silicon, cadmium sulfide/copper sulfide thin films, as well as other materials and devices for solar cell energy conversion systems.

  1. Assessment of the technology required to develop photovoltaic power system for large scale national energy applications

    NASA Technical Reports Server (NTRS)

    Lutwack, R.

    1974-01-01

    A technical assessment of a program to develop photovoltaic power system technology for large-scale national energy applications was made by analyzing and judging the alternative candidate photovoltaic systems and development tasks. A program plan was constructed based on achieving the 10 year objective of a program to establish the practicability of large-scale terrestrial power installations using photovoltaic conversion arrays costing less than $0.50/peak W. Guidelines for the tasks of a 5 year program were derived from a set of 5 year objectives deduced from the 10 year objective. This report indicates the need for an early emphasis on the development of the single-crystal Si photovoltaic system for commercial utilization; a production goal of 5 x 10 to the 8th power peak W/year of $0.50 cells was projected for the year 1985. The developments of other photovoltaic conversion systems were assigned to longer range development roles. The status of the technology developments and the applicability of solar arrays in particular power installations, ranging from houses to central power plants, was scheduled to be verified in a series of demonstration projects. The budget recommended for the first 5 year phase of the program is $268.5M.

  2. Propulsion system for a motor vehicle using a bidirectional energy converter

    SciTech Connect

    Tamor, M.A.; Gale, A.R.

    1999-12-07

    A motor vehicle propulsion system includes an electrical energy source and a traction motor coupled to receive electrical energy from the electrical energy source. The system also has a first bus provided electrical energy by the electrical energy source and a second bus of relatively lower voltage than the first bus. In addition, the system includes an electrically-driven source of reaction gas for the electrical energy source, the source of reaction gas coupled to receive electrical energy from the first bus. Also, the system has an electrical storage device coupled to the second bus for storing electrical energy at the lower voltage. The system also includes a bidirectional energy converter coupled to convert electrical energy from the first bus to the second bus and from the second bus to the first bus.

  3. Propulsion system for a motor vehicle using a bidirectional energy converter

    DOEpatents

    Tamor, Michael Alan; Gale, Allan Roy

    1999-01-01

    A motor vehicle propulsion system includes an electrical energy source and a traction motor coupled to receive electrical energy from the electrical energy source. The system also has a first bus provided electrical energy by the electrical energy source and a second bus of relatively lower voltage than the first bus. In addition, the system includes an electrically-driven source of reaction gas for the electrical energy source, the source of reaction gas coupled to receive electrical energy from the first bus. Also, the system has an electrical storage device coupled to the second bus for storing electrical energy at the lower voltage. The system also includes a bidirectional energy converter coupled to convert electrical energy from the first bus to the second bus and from the second bus to the first bus.

  4. Potential applications of photovoltaic energy for pumping and desalting Australian groundwater using brushless DC motors

    SciTech Connect

    Longrigg, P.

    1984-08-01

    This paper discusses methods and techniques for transporting and desalting groundwater supplies using the renewable energy derived from solar photovoltaic systems. The reliability of this type of equipment is emphasized, which operates in remote areas far from other power supplies and maintenance facilities. Until relatively recently, the cost of photovoltaic arrays in remote areas, compared with thermal methods of desalination, precluded their use. But recent developments in photovoltaic technology have changed this. The use of brushless dc motors directly coupled to the PV array eliminates the cost of inverter power conditioning required for ac induction motors. The PV/brushless dc motor configuration yields a particularly good technical fit for pumping and desalting groundwater in the Australian Outback.

  5. Life Cycle Assessment Projection of Photovoltaic Cells: A Case Study on Energy Demand of Quantum Wire Based Photovoltaic Technology Research

    NASA Astrophysics Data System (ADS)

    Mukherjee, Shilpi

    With increasing clean-energy demand, photovoltaic (PV) technologies have gained attention as potential long-term alternative to fossil fuel energy. However, PV research and manufacture still utilize fossil fuel-powered grid electricity. With continuous enhancement of solar conversion efficiency, it is imperative to assess whether overall life cycle efficiency is also being enhanced. Many new-material PV technologies are still in their research phase, and life cycle analyses of these technologies have not yet been performed. For best results, grid dependency must be minimized for PV research, and this can be accomplished by an analytical instrument called Life Cycle Assessment (LCA). LCA is the study of environmental impacts of a product throughout its life cycle. While there are some non-recoverable costs of research, energy is precious, and the PV research community should be aware of its energy consumption. LCA can help identify options for energy conservation through process optimization. A case study was conducted on the energy demand of a test-bed emerging PV technology using life cycle assessment methodology. The test-bed system chosen for this study was a new-material PV cell. The objective was to quantify the total energy demand for the research phase of the test-bed solar cell's life cycle. The objective was accomplished by collecting primary data on energy consumption for each process in the development of this solar cell. It was found that 937 kWh of energy was consumed for performing research on a single sample of the solar cell. For comparison, this energy consumption is 83% of Arkansas's average monthly residential electricity consumption. Life cycle inventory analysis showed that heating, ventilation, and air conditioning consumed the bulk of the energy of research. It is to be noted that the processes studied as part of the solar cell test-bed system are representative of a research process only. Life cycle thinking can identify energy hot-spots and

  6. Static Converter for High Energy Utilization, Modular, Small Nuclear Power Plants

    SciTech Connect

    El-Genk, Mohamed S.; Tournier, Jean-Michel P.

    2002-07-01

    This paper presents and analyzes the performance of high efficiency, high total energy utilization, static converters, which could be used in conjunction with small nuclear reactor plants in remote locations and in undersea applications, requiring little or no maintenance. The converters consist of a top cycle of Alkali Metal Thermal-to-Electric Conversion (AMTEC) units and PbTe thermoelectric (TE) bottom cycle. In addition to converting the reactor thermal power to electricity at 1150 K or less, at a thermodynamic efficiency in the low to mid thirties, the heat rejection from the TE bottom cycle could be used for space heating, industrial processing, or sea water desalination. The results indicated that for space heating applications, where the rejected thermal power from the TE bottom cycle is removed by natural convection of ambient air, a total utilization of the reactor thermal power of > 80% is possible. When operated at 1030 K, potassium AMTEC/TE converters are not only more efficient than the sodium AMTEC/TE converters but produce more electrical power. The present analysis showed that a single converter could be sized to produce up to 100 kWe and 70 kWe, for the Na-AMTEC/TE units when operating at 1150 K and the K-AMTEC/TE units when operating at 1030 K, respectively. Such modularity is an added advantage to the high-energy utilization of the present AMTEC/TE converters. (authors)

  7. The Remote Maxwell Demon as Energy Down-Converter

    NASA Astrophysics Data System (ADS)

    Hossenfelder, S.

    2016-04-01

    It is demonstrated that Maxwell's demon can be used to allow a machine to extract energy from a heat bath by use of information that is processed by the demon at a remote location. The model proposed here effectively replaces transmission of energy by transmission of information. For that we use a feedback protocol that enables a net gain by stimulating emission in selected fluctuations around thermal equilibrium. We estimate the down conversion rate and the efficiency of energy extraction from the heat bath.

  8. Neural rotational speed control for wave energy converters

    NASA Astrophysics Data System (ADS)

    Amundarain, M.; Alberdi, M.; Garrido, A. J.; Garrido, I.

    2011-02-01

    Among the benefits arising from an increasing use of renewable energy are: enhanced security of energy supply, stimulation of economic growth, job creation and protection of the environment. In this context, this study analyses the performance of an oscillating water column device for wave energy conversion in function of the stalling behaviour in Wells turbines, one of the most widely used turbines in wave energy plants. For this purpose, a model of neural rotational speed control system is presented, simulated and implemented. This scheme is employed to appropriately adapt the speed of the doubly-fed induction generator coupled to the turbine according to the pressure drop entry, so as to avoid the undesired stalling behaviour. It is demonstrated that the proposed neural rotational speed control design adequately matches the desired relationship between the slip of the doubly-fed induction generator and the pressure drop input, improving the power generated by the turbine generator module.

  9. Organic photovoltaics

    NASA Astrophysics Data System (ADS)

    Demming, Anna; Krebs, Frederik C.; Chen, Hongzheng

    2013-12-01

    Energy inflation, the constant encouragement to economize on energy consumption and the huge investments in developing alternative energy resources might seem to suggest that there is a global shortage of energy. Far from it, the energy the Sun beams on the Earth each hour is equivalent to a year's supply, even at our increasingly ravenous rate of global energy consumption [1]. But it's not what you have got it's what you do with it. Hence the intense focus on photovoltaic research to find more efficient ways to harness energy from the Sun. Recently much of this research has centred on organic solar cells since they offer simple, low-cost, light-weight and large-area flexible photovoltaic structures. This issue with guest editors Frederik C Krebs and Hongzheng Chen focuses on some of the developments at the frontier of organic photovoltaic technology. Improving the power conversion efficiency of organic photovoltaic systems, while maintaining the inherent material, economic and fabrication benefits, has absorbed a great deal of research attention in recent years. Here significant progress has been made with reports now of organic photovoltaic devices with efficiencies of around 10%. Yet operating effectively across the electromagnetic spectrum remains a challenge. 'The trend is towards engineering low bandgap polymers with a wide optical absorption range and efficient hole/electron transport materials, so that light harvesting in the red and infrared region is enhanced and as much light of the solar spectrum as possible can be converted into an electrical current', explains Mukundan Thelakkat and colleagues in Germany, the US and UK. In this special issue they report on how charge carrier mobility and morphology of the active blend layer in thin film organic solar cells correlate with device parameters [2]. The work contributes to a better understanding of the solar-cell characteristics of polymer:fullerene blends, which form the material basis for some of the most

  10. Muon detection studied by pulse-height energy analysis: Novel converter arrangements

    SciTech Connect

    Holmlid, Leif; Olafsson, Sveinn

    2015-08-15

    Muons are conventionally measured by a plastic scintillator–photomultiplier detector. Muons from processes in ultra-dense hydrogen H(0) are detected here by a novel type of converter in front of a photomultiplier. The muon detection yield can be increased relative to that observed with a plastic scintillator by at least a factor of 100, using a converter of metal, semiconductor (Ge), or glass for interaction with the muons penetrating through the metal housing of the detector. This detection process is due to transient formation of excited nuclei by the well-known process of muon capture, giving beta decay. The main experimental results shown here are in the form of beta electron energy spectra detected directly by the photomultiplier. Events which give a high-energy tail in the energy spectra are probably due to gamma photons from the muons. Sharp and intense x-ray peaks from a muonic aluminium converter or housing material are observed. The detection conversion in glass and Ge converters has a time constant of the order of many minutes to reach the final conversion level, while the process in metal converters is stabilized faster. The time constants are not due to lifetimes of the excited nuclei or neutrons but are due to internal charging in the insulating converter material. Interaction of this charging with the high voltage in the photomultiplier is observed.

  11. Muon detection studied by pulse-height energy analysis: Novel converter arrangements.

    PubMed

    Holmlid, Leif; Olafsson, Sveinn

    2015-08-01

    Muons are conventionally measured by a plastic scintillator-photomultiplier detector. Muons from processes in ultra-dense hydrogen H(0) are detected here by a novel type of converter in front of a photomultiplier. The muon detection yield can be increased relative to that observed with a plastic scintillator by at least a factor of 100, using a converter of metal, semiconductor (Ge), or glass for interaction with the muons penetrating through the metal housing of the detector. This detection process is due to transient formation of excited nuclei by the well-known process of muon capture, giving beta decay. The main experimental results shown here are in the form of beta electron energy spectra detected directly by the photomultiplier. Events which give a high-energy tail in the energy spectra are probably due to gamma photons from the muons. Sharp and intense x-ray peaks from a muonic aluminium converter or housing material are observed. The detection conversion in glass and Ge converters has a time constant of the order of many minutes to reach the final conversion level, while the process in metal converters is stabilized faster. The time constants are not due to lifetimes of the excited nuclei or neutrons but are due to internal charging in the insulating converter material. Interaction of this charging with the high voltage in the photomultiplier is observed. PMID:26329180

  12. Muon detection studied by pulse-height energy analysis: Novel converter arrangements

    NASA Astrophysics Data System (ADS)

    Holmlid, Leif; Olafsson, Sveinn

    2015-08-01

    Muons are conventionally measured by a plastic scintillator-photomultiplier detector. Muons from processes in ultra-dense hydrogen H(0) are detected here by a novel type of converter in front of a photomultiplier. The muon detection yield can be increased relative to that observed with a plastic scintillator by at least a factor of 100, using a converter of metal, semiconductor (Ge), or glass for interaction with the muons penetrating through the metal housing of the detector. This detection process is due to transient formation of excited nuclei by the well-known process of muon capture, giving beta decay. The main experimental results shown here are in the form of beta electron energy spectra detected directly by the photomultiplier. Events which give a high-energy tail in the energy spectra are probably due to gamma photons from the muons. Sharp and intense x-ray peaks from a muonic aluminium converter or housing material are observed. The detection conversion in glass and Ge converters has a time constant of the order of many minutes to reach the final conversion level, while the process in metal converters is stabilized faster. The time constants are not due to lifetimes of the excited nuclei or neutrons but are due to internal charging in the insulating converter material. Interaction of this charging with the high voltage in the photomultiplier is observed.

  13. Optimum irradiance distribution of concentrated sunlight for photovoltaic energy conversion

    NASA Astrophysics Data System (ADS)

    Benítez, Pablo; Mohedano, Rubén

    1999-04-01

    The irradiance distribution on a concentration photovoltaic cell that produces maximum conversion efficiency has been found with the tools of Variational Calculus. The analysis is two dimensional and can be applied to a comb-like double busbar solar cell illuminated by a line-focus concentrator. The optimum distribution is, in general, nonuniform, and depends on the internal parameters of the solar cell: the higher the contribution of the grid to the global cell series resistance, the lower the uniformity of the optimum irradiance distribution. In practical cases, the efficiency for uniform illumination is close to that of the optimum, but in the latter the irradiance close to the busbar may be noticeable higher than the average.

  14. CONVERTING ENERGY FROM RECLAIMED HEAT: THERMAL ELECTRIC GENERATOR

    EPA Science Inventory

    The use of solar energy acquiring devices has been slow to gain acceptance due to their overall low power generation versus high cost of a solar system. The goal of this project is to construct a model which increases the overall power generation of a solar building system by...

  15. Electricity from photovoltaic solar cells. Flat-Plate Solar Array Project of the US Department of Energy's National Photovoltaics Program: 10 years of progress

    NASA Technical Reports Server (NTRS)

    Christensen, Elmer

    1985-01-01

    The objectives were to develop the flat-plate photovoltaic (PV) array technologies required for large-scale terrestrial use late in the 1980s and in the 1990s; advance crystalline silicon PV technologies; develop the technologies required to convert thin-film PV research results into viable module and array technology; and to stimulate transfer of knowledge of advanced PV materials, solar cells, modules, and arrays to the PV community. Progress reached on attaining these goals, along with future recommendations are discussed.

  16. Energy analysis of facade-integrated photovoltaic systems applied to UAE commercial buildings

    SciTech Connect

    Radhi, Hassan

    2010-12-15

    Developments in the design and manufacture of photovoltaic cells have recently been a growing concern in the UAE. At present, the embodied energy pay-back time (EPBT) is the criterion used for comparing the viability of such technology against other forms. However, the impact of PV technology on the thermal performance of buildings is not considered at the time of EPBT estimation. If additional energy savings gained over the PV system life are also included, the total EPBT could be shorter. This paper explores the variation of the total energy of building integrated photovoltaic systems (BiPV) as a wall cladding system applied to the UAE commercial sector and shows that the ratio between PV output and saving in energy due to PV panels is within the range of 1:3-1:4. The result indicates that for the southern and western facades in the UAE, the embodied energy pay-back time for photovoltaic system is within the range of 12-13 years. When reductions in operational energy are considered, the pay-back time is reduced to 3.0-3.2 years. This study comes to the conclusion that the reduction in operational energy due to PV panels represents an important factor in the estimation of EPBT. (author)

  17. The research of multilevel transistor inverter for converting energy of solar panels

    NASA Astrophysics Data System (ADS)

    Taissariyeva, K. N.; Issembergenov, N. T.

    2015-09-01

    This article considers multilevel transistor inverter for converting energy of solar panels into electroenergy. The output of multilevel transistor inverter produces the voltage of almost sinusoidal form. The primary objective of this inverter is to transform solar energy into electroenergy of industrial frequency. The analysis of received output curves of voltage for sinusoidality has been conducted.

  18. Model predictive control of bidirectional isolated DC-DC converter for energy conversion system

    NASA Astrophysics Data System (ADS)

    Akter, Parvez; Uddin, Muslem; Mekhilef, Saad; Tan, Nadia Mei Lin; Akagi, Hirofumi

    2015-08-01

    Model predictive control (MPC) is a powerful and emerging control algorithm in the field of power converters and energy conversion systems. This paper proposes a model predictive algorithm to control the power flow between the high-voltage and low-voltage DC buses of a bidirectional isolated full-bridge DC-DC converter. The predictive control algorithm utilises the discrete nature of the power converters and predicts the future nature of the system, which are compared with the references to calculate the cost function. The switching state that minimises the cost function is selected for firing the converter in the next sampling time period. The proposed MPC bidirectional DC-DC converter is simulated with MATLAB/Simulink and further verified with a 2.5 kW experimental configuration. Both the simulation and experimental results confirm that the proposed MPC algorithm of the DC-DC converter reduces reactive power by avoiding the phase shift between primary and secondary sides of the high-frequency transformer and allow power transfer with unity power factor. Finally, an efficiency comparison is performed between the MPC and dual-phase-shift-based pulse-width modulation controlled DC-DC converter which ensures the effectiveness of the MPC controller.

  19. The Wave Carpet: An Omnidirectional and Broadband Wave Energy Converter

    NASA Astrophysics Data System (ADS)

    Alam, M.-Reza

    2015-11-01

    Inspired by the strong attenuation of ocean surface waves by muddy seafloors, we have designed, theoretically investigated the performance, and experimentally tested the ``Wave Carpet:'' a mud-resembling synthetic seabed-mounted mat composed of vertically-acting linear springs and generators that can be used as an efficient wave energy absorption device. The Wave Carpet is completely under the water surface hence imposes minimal danger to boats and the sea life (i.e. no mammal entanglement). It is survivable against the high momentum of storm surges and in fact can perform even better under very energetic (e.g. stormy) sea conditions when most existing wave energy devices are needed to shelter themselves by going into an idle mode. In this talk I will present an overview of analytical results for the linear problem, direct simulation of highly nonlinear wave fields, and results of the experimental wave tank investigation.

  20. High temperature solid oxide regenerative fuel cell for solar photovoltaic energy storage

    NASA Technical Reports Server (NTRS)

    Bents, David J.

    1987-01-01

    A hydrogen-oxygen regenerative fuel cell (RFC) energy storage system based on high temperature solid oxide fuel cell (SOFC) technology is described. The reactants are stored as gases in lightweight insulated pressure vessels. The product water is stored as a liquid in saturated equilibrium with the fuel gas. The system functions as a secondary battery and is applicable to darkside energy storage for solar photovoltaics.

  1. Underwater Noise from a Wave Energy Converter Is Unlikely to Affect Marine Mammals.

    PubMed

    Tougaard, Jakob

    2015-01-01

    Underwater noise was recorded from the Wavestar wave energy converter; a full-scale hydraulic point absorber, placed on a jack-up rig on the Danish North Sea coast. Noise was recorded 25 m from the converter with an autonomous recording unit (10 Hz to 20 kHz bandwidth). Median sound pressure levels (Leq) in third-octave bands during operation of the converter were 106-109 dB re. 1 μPa in the range 125-250 Hz, 1-2 dB above ambient noise levels (statistically significant). Outside the range 125-250 Hz the noise from the converter was undetectable above the ambient noise. During start and stop of the converter a more powerful tone at 150 Hz (sound pressure level (Leq) 121-125 dB re 1 μPa) was easily detectable. This tone likely originated from the hydraulic pump which was used to lower the absorbers into the water and lift them out of the water at shutdown. Noise levels from the operating wave converter were so low that they would barely be audible to marine mammals and the likelihood of negative impact from the noise appears minimal. A likely explanation for the low noise emissions is the construction of the converter where all moving parts, except for the absorbers themselves, are placed above water on a jack-up rig. The results may thus not be directly transferable to other wave converter designs but do demonstrate that it is possible to harness wave energy without noise pollution to the marine environment. PMID:26148299

  2. Underwater Noise from a Wave Energy Converter Is Unlikely to Affect Marine Mammals

    PubMed Central

    Tougaard, Jakob

    2015-01-01

    Underwater noise was recorded from the Wavestar wave energy converter; a full-scale hydraulic point absorber, placed on a jack-up rig on the Danish North Sea coast. Noise was recorded 25 m from the converter with an autonomous recording unit (10 Hz to 20 kHz bandwidth). Median sound pressure levels (Leq) in third-octave bands during operation of the converter were 106–109 dB re. 1 μPa in the range 125–250 Hz, 1–2 dB above ambient noise levels (statistically significant). Outside the range 125–250 Hz the noise from the converter was undetectable above the ambient noise. During start and stop of the converter a more powerful tone at 150 Hz (sound pressure level (Leq) 121–125 dB re 1 μPa) was easily detectable. This tone likely originated from the hydraulic pump which was used to lower the absorbers into the water and lift them out of the water at shutdown. Noise levels from the operating wave converter were so low that they would barely be audible to marine mammals and the likelihood of negative impact from the noise appears minimal. A likely explanation for the low noise emissions is the construction of the converter where all moving parts, except for the absorbers themselves, are placed above water on a jack-up rig. The results may thus not be directly transferable to other wave converter designs but do demonstrate that it is possible to harness wave energy without noise pollution to the marine environment. PMID:26148299

  3. High frequency converters for thermophotovoltaic applications

    SciTech Connect

    Fatemi, N.S.; Hoffman, R.W. Jr.; Lowe, R.A.; Jenkins, P.P.; Garverick, L.M.; Wilt, D.M.; Scheiman, D.

    1996-12-31

    Thermophotovoltaic (TPV) converters were developed and tested at the heat source operating temperature of 1,700 K. Rare-earth-doped yttrium aluminum garnet (YAG) and lutetium yttrium aluminum garnet (Lu, YAG) selective emitters, as well as a blackbody emitter, were coupled to InGaAs/InP photovoltaic (PV) cells and bandpass/infrared (IR) reflector filters. YAG-based selective emitters were adopted with Ho, Tm, and Er. PV cells had bandgaps of 0.51, 0.57, and 0.69 eV. Converter energy conversion efficiencies approaching 30%, as well as electrical output power densities near 2 W/cm{sup 2} were demonstrated. The overall performance of the filtered blackbody-based converter was found to be superior to the selective emitter YAG-based converters. The details of the measurements performed on the above converters and their individual components are presented.

  4. An empirical study on energy efficiency improvement through photovoltaic systems and a LED lighting control system

    NASA Astrophysics Data System (ADS)

    Choi, Young Kwan; Lee, Jae Hyeong

    2015-09-01

    In this research, a facility was constructed and its performance was analyzed to improve the energy efficiency of a vertical-type water treatment building. After the design and construction of a fixed tilt Photovoltaic in Building (PVIB) on the rooftop using a crystalline silicon solar cell module and photovoltaic generator integrated with the building by using a Building Integrated Photovoltaic System (BIPV), a thin-film module on the rooftop and outer wall of water treatment building, and the generation efficiency was analyzed. Also, a DC distribution was established for use of a brushless DC (BLDC) pump motor, and the existing lighting-facility-based manual on-off method was turned into a system for energy conservation by controlling light emitting diode (LED) through a wireless motion sensor and dimming control. In addition, a Building Energy Management System (BEMS) for a real-time analysis of the energy efficiency for a vertical0type water treatment building was prepared and tested. The vertical-type water treatment building developed in this study is currently operating the BEMS. The vertical-type water treatment building reported in this paper is expected to reduce energy consumption by about 30% compared to existing water treatment systems.

  5. Large impact of reorganization energy on photovoltaic conversion due to interfacial charge-transfer transitions.

    PubMed

    Fujisawa, Jun-ichi

    2015-05-14

    Interfacial charge-transfer (ICT) transitions are expected to be a novel charge-separation mechanism for efficient photovoltaic conversion featuring one-step charge separation without energy loss. Photovoltaic conversion due to ICT transitions has been investigated using several TiO2-organic hybrid materials that show organic-to-inorganic ICT transitions in the visible region. In applications of ICT transitions to photovoltaic conversion, there is a significant problem that rapid carrier recombination is caused by organic-inorganic electronic coupling that is necessary for the ICT transitions. In order to solve this problem, in this work, I have theoretically studied light-to-current conversions due to the ICT transitions on the basis of the Marcus theory with density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations. An apparent correlation between the reported incident photon-to-current conversion efficiencies (IPCE) and calculated reorganization energies was clearly found, in which the IPCE increases with decreasing the reorganization energy consistent with the Marcus theory in the inverted region. This activation-energy dependence was systematically explained by the equation formulated by the Marcus theory based on a simple excited-state kinetic scheme. This result indicates that the reduction of the reorganization energy can suppress the carrier recombination and enhance the IPCE. The reorganization energy is predominantly governed by the structural change in the chemical-adsorption moiety between the ground and ICT excited states. This work provides crucial knowledge for efficient photovoltaic conversion due to ICT transitions. PMID:25892453

  6. Tariffs Can Be Structured to Encourage Photovoltaic Energy

    SciTech Connect

    Wiser, Ryan; Mills, Andrew; Barbose, Galen; Golove, William

    2008-08-31

    The solar power market is growing at a quickening pace, fueled by an array of national and local initiatives and policies aimed at improving the value proposition of customer-sited photovoltaic (PV) systems. Though these policies take many forms, they commonly include up-front capital cost rebates or ongoing production incentives, supplemented by net metering requirements to ensure that customer-sited PV systems offset the full retail rate of the customer-hosts. Somewhat less recognized is the role of retail rate design, beyond net metering, on the customer-economics of grid-connected PV. Over the life of a PV system, utility bill savings represent a substantial portion of the overall economic value received by the customer. At the same time, the design of retail electricity rates, particularly for commercial and industrial customers, can vary quite substantially. Understanding how specific differences in rate design affect the value of customer-sited PV is therefore essential to supporting the continued growth of this market.

  7. Photovoltaics Informatics: Harnessing Energy Science via Data-Driven Approaches

    SciTech Connect

    Suh, C.; Munch, K.; Biagioni, D.; Glynn, S.; Scharf, J.; Contreras, M. A.; Perkins, J. D.; Nelson, B. P.; Jones, W. B.

    2011-01-01

    We discuss our current research focus on photovoltaic (PV) informatics, which is dedicated to functionality enhancement of solar materials through data management and data mining-aided, integrated computational materials engineering (ICME) for rapid screening and identification of multi-scale processing/structure/property/performance relationships. Our current PV informatics research ranges from transparent conducting oxides (TCO) to solar absorber materials. As a test bed, we report on examples of our current data management system for PV research and advanced data mining to improve the performance of solar cells such as CuIn{sub x}Ga{sub 1-x}Se{sub 2} (CIGS) aiming at low-cost and high-rate processes. For the PV data management, we show recent developments of a strategy for data modeling, collection and aggregation methods, and construction of data interfaces, which enable proper archiving and data handling for data mining. For scientific data mining, the value of high-dimensional visualizations and non-linear dimensionality reduction is demonstrated to quantitatively assess how process conditions or properties are interconnected in the context of the development of Al-doped ZnO (AZO) thin films as the TCO layers for CIGS devices. Such relationships between processing and property of TCOs lead to optimal process design toward enhanced performance of CIGS cells/devices.

  8. Ovshinsky Sustainable Energy Fellowship: Excitonics for Transparent Photovoltaics

    NASA Astrophysics Data System (ADS)

    Lunt, Richard

    Room-­temperature excitonic materials offer new opportunities for low­-cost photovoltaic (PV) systems and provide prospects for unique solar harvesting science and applications. In the first part of this talk, I will introduce our pioneering work on developing transparent PVs that are creating a new paradigm for seamless solar harvesting around buildings, automobiles, and mobile electronics. These devices are enabled by the manipulation of excitonic semiconductor materials with selective harvesting in the near­infrared and ultraviolet components of the solar spectrum. I will describe key photophysical properties, outline the thermodynamic and practical limits to these new classes of materials and devices, and briefly discuss their commercial impact for a range of applications. In the second part, I will describe the development of a new series organic salts that allow tunable photoresponse from 900nm to 1600nm, an unprecedented range for small­molecule semiconductors. These organic salts also enable precise tuning of frontier orbital levels and heterojunction interface gaps through anion alloying that result in voltages near the thermodynamic limit. This design strategy can further enable rapid development of efficient and low­cost multijunction devices (both opaque and transparent) with complimentary response across the solar spectrum.

  9. 100kW Energy Transfer Multiplexer Power Converter Prototype Development Project

    SciTech Connect

    S. Merrill Skeist; Richard H. Baker; Anthony G.P. Marini; DOE Project Officer - Keith Bennett

    2006-03-21

    Project Final Report for "100kW Energy Transfer Multiplexer Power Converter Prototype Development Project" prepared under DOE grant number DE-FG36-03GO13138. This project relates to the further development and prototype construction/evaluation for the Energy Transfer Multiplexer (ETM) power converter topology concept. The ETM uses a series resonant link to transfer energy from any phase of a multiphase input to any phase of a multiphase output, converting any input voltage and frequency to any output voltage and frequency. The basic form of the ETM converter consists of an eight (8)-switch matrix (six phase power switches and two ground power switches) and a series L-C resonant circuit. Electronic control of the switches allows energy to be transferred in the proper amount from any phase to any other phase. Depending upon the final circuit application, the switches may be either SCRs or IGBTs. The inherent characteristics of the ETM converter include the following: Power processing in either direction (bidirectional); Large voltage gain without the need of low frequency magnetics; High efficiency independent of output load and frequency; Wide bandwidth with fast transient response and; Operation as a current source. The ETM is able to synthesize true sinusoidal waveforms with low harmonic distortions. For a low power PM wind generation system, the ETM has the following characteristics and advantages: It provides voltage gain without the need of low frequency magnetics (DC inductors) and; It has constant high efficiency independent of the load. The ETM converter can be implemented into a PM wind power system with smaller size, reduced weight and lower cost. As a result of our analyses, the ETM offers wind power generation technology for the reduction of the cost and size as well as the increase in performance of low power, low wind speed power generation. This project is the further theoretical/analytical exploration of the ETM converter concept in relationship to

  10. Analog to digital converter for two-dimensional radiant energy array computers

    NASA Technical Reports Server (NTRS)

    Shaefer, D. H.; Strong, J. P., III (Inventor)

    1977-01-01

    The analog to digital converter stage derives a bit array of digital radiant energy signals representative of the amplitudes of an input radiant energy analog signal array and derives an output radiant energy analog signal array to serve as an input to succeeding stages. The converter stage includes a digital radiant energy array device which contains radiant energy array positions so that the analog array is less than a predetermined threshold level. A scaling device amplifies the radiant signal levels of the input array and the digital array so that the radiant energy signal level carried by the digital array corresponds to the threshold level. An adder device adds the signals of the scaled input and digital arrays at corresponding array positions to form the output analog array.

  11. Analysis on Dissemination Conditions of Photovoltaics in Japan by Using Energy System Model MARKAL

    NASA Astrophysics Data System (ADS)

    Endo, Eiichi; Ichinohe, Masayuki

    The national target for PV capacity in Japan is 4. 82, GW in 2010, and several PV Roadmaps until 2030 are also described. To achieve the target, several support programs, such as subsidization to capital cost, Green Credit by the Green Power Certification System, buy-back under the Renewable Portfolio Standard low, have been already introduced. Carbon tax is still under consideration, but there are several analyses about possible carbon tax. The purpose of this paper is to analyze PV system sales price and subsidy through buy-back which make photovoltaics cost-competitive with other energy technologies and make the target for PV capacity achievable by 2030 in Japan under an expected carbon tax. For the analysis energy system of Japan is modeled by using MARKAL. Based on the results of analysis, under 6000, JPY/t-C carbon tax, photovoltaics needs subsidy for a while even if we taking both fuel savings and Green Credit into account. For attaining the national target for PV capacity in 2010, photovoltaics needs more expensive buy-back than that in present, but after 2010 necessary buy-back decreases gradually. If 120, JPY/W PV system sales price is attained by 2030, photovoltaics becomes cost-competitive without any supports. Subsidy through buy-back becomes almost unnecessary in 2030, if we can reduce it less than 170, JPY/W. The total necessary buy-back meets peak in 2025. It is much more than ongoing subsidy to capital cost of PV systems, but annual revenue from the assumed carbon tax can finance the annual total necessary buy-back. This means if photovoltaics can attain the targeted PV system sales price, we should support it for a while by spending carbon tax revenue effectively and efficiently.

  12. Real-time Ocean Wave Prediction for Optimal Performance of a Wave Energy Converter

    NASA Astrophysics Data System (ADS)

    Cavaglieri, Daniele; Bewley, Thomas

    2013-11-01

    In recent years, there has been a growing interest in renewable energy. Among all the available possibilities, wave energy conversion, due to the huge availability of energy that the ocean could provide, represents nowadays one of the most promising solutions. However, the efficiency of a wave energy converter for ocean wave energy harvesting is still far from making it competitive with more mature fields of renewable energy, such as solar and wind energy. One of the main problems is related to the inability to accurately predict the profile of oncoming waves approaching the wave energy converter. For this reason, we developed a new hybrid method for state estimation of nonlinear systems, which is based on a variational formulation of an ensemble smoother, combined with the formulation of the ensemble Kalman smoother. This method has been employed for the optimal forecasting of ocean waves via sensors placed on an array of wave energy converters. The coupled simulation of ocean waves and energy devices has been carried out leveraging a nonlinear High Order Spectral code.

  13. A mechanical energy harvested magnetorheological damper with linear-rotary motion converter

    NASA Astrophysics Data System (ADS)

    Chu, Ki Sum; Zou, Li; Liao, Wei-Hsin

    2016-04-01

    Magnetorheological (MR) dampers are promising to substitute traditional oil dampers because of adaptive properties of MR fluids. During vibration, significant energy is wasted due to the energy dissipation in the damper. Meanwhile, for conventional MR damping systems, extra power supply is needed. In this paper, a new energy harvester is designed in an MR damper that integrates controllable damping and energy harvesting functions into one device. The energy harvesting part of this MR damper has a unique mechanism converting linear motion to rotary motion that would be more stable and cost effective when compared to other mechanical transmissions. A Maxon motor is used as a power generator to convert the mechanical energy into electrical energy to supply power for the MR damping system. Compared to conventional approaches, there are several advantages in such an integrated device, including weight reduction, ease in installation with less maintenance. A mechanical energy harvested MR damper with linear-rotary motion converter and motion rectifier is designed, fabricated, and tested. Experimental studies on controllable damping force and harvested energy are performed with different transmissions. This energy harvesting MR damper would be suitable to vehicle suspensions, civil structures, and smart prostheses.

  14. Design of Energy Storage Reactors for Dc-To-Dc Converters. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Chen, D. Y.

    1975-01-01

    Two methodical approaches to the design of energy-storage reactors for a group of widely used dc-to-dc converters are presented. One of these approaches is based on a steady-state time-domain analysis of piecewise-linearized circuit models of the converters, while the other approach is based on an analysis of the same circuit models, but from an energy point of view. The design procedure developed from the first approach includes a search through a stored data file of magnetic core characteristics and results in a list of usable reactor designs which meet a particular converter's requirements. Because of the complexity of this procedure, a digital computer usually is used to implement the design algorithm. The second approach, based on a study of the storage and transfer of energy in the magnetic reactors, leads to a straightforward design procedure which can be implemented with hand calculations. An equation to determine the lower-bound volume of workable cores for given converter design specifications is derived. Using this computer lower-bound volume, a comparative evaluation of various converter configurations is presented.

  15. Converting chemical energy into electricity through a functionally cooperating device with diving-surfacing cycles.

    PubMed

    Song, Mengmeng; Cheng, Mengjiao; Ju, Guannan; Zhang, Yajun; Shi, Feng

    2014-11-01

    A smart device that can dive or surface in aqueous medium has been developed by combining a pH-responsive surface with acid-responsive magnesium. The diving-surfacing cycles can be used to convert chemical energy into electricity. During the diving-surfacing motion, the smart device cuts magnetic flux lines and produces a current, demonstrating that motional energy can be realized by consuming chemical energy of magnesium, thus producing electricity. PMID:25146589

  16. Investigation of energy management strategies for photovoltaic systems - A predictive control algorithm

    NASA Technical Reports Server (NTRS)

    Cull, R. C.; Eltimsahy, A. H.

    1983-01-01

    The present investigation is concerned with the formulation of energy management strategies for stand-alone photovoltaic (PV) systems, taking into account a basic control algorithm for a possible predictive, (and adaptive) controller. The control system controls the flow of energy in the system according to the amount of energy available, and predicts the appropriate control set-points based on the energy (insolation) available by using an appropriate system model. Aspects of adaptation to the conditions of the system are also considered. Attention is given to a statistical analysis technique, the analysis inputs, the analysis procedure, and details regarding the basic control algorithm.

  17. Design considerations for a thermophotovoltaic energy converter using heat pipe radiators

    SciTech Connect

    Ashcroft, J.; DePoy, D.

    1997-06-01

    The purpose of this paper is to discuss concepts for using high temperature heat pipes to transport energy from a heat source to a thermophotovoltaic (TPV) converter. Within the converter, the condenser portion of each heat pipe acts as a photon radiator, providing a radiant flux to adjacent TPV cells, which in turn create electricity. Using heat pipes in this way could help to increase the power output and the power density of TPV systems. TPV systems with radiator temperatures in the range of 1,500 K are expected to produce as much as 3.6 W/cm{sup 3} of heat exchanger volume at an efficiency of 20% or greater. Four different arrangements of heat pipe-TPV energy converters are considered. Performance and sizing calculations for each of the concepts are presented. Finally, concerns with this concept and issues which remain to be considered are discussed.

  18. Development of low-cost silicon crystal growth techniques for terrestrial photovoltaic solar energy conversion

    NASA Technical Reports Server (NTRS)

    Zoutendyk, J. A.

    1976-01-01

    Because of the growing need for new sources of electrical energy, photovoltaic solar energy conversion is being developed. Photovoltaic devices are now being produced mainly from silicon wafers obtained from the slicing and polishing of cylindrically shaped single crystal ingots. Inherently high-cost processes now being used must either be eliminated or modified to provide low-cost crystalline silicon. Basic to this pursuit is the development of new or modified methods of crystal growth and, if necessary, crystal cutting. If silicon could be grown in a form requiring no cutting, a significant cost saving would potentially be realized. Therefore, several techniques for growth in the form of ribbons or sheets are being explored. In addition, novel techniques for low-cost ingot growth and cutting are under investigation.

  19. Cost of photovoltaic energy systems as determined by balance-of-system costs

    NASA Technical Reports Server (NTRS)

    Rosenblum, L.

    1978-01-01

    The effect of the balance-of-system (BOS), i.e., the total system less the modules, on photo-voltaic energy system costs is discussed for multikilowatt, flat-plate systems. Present BOS costs are in the range of 10 to 16 dollars per peak watt (1978 dollars). BOS costs represent approximately 50% of total system cost. The possibility of future BOS cost reduction is examined. It is concluded that, given the nature of BOS costs and the lack of comprehensive national effort focussed on cost reduction, it is unlikely that BOS costs will decline greatly in the next several years. This prognosis is contrasted with the expectations of the Department of Energy National Photovoltaic Program goals and pending legislation in the Congress which require a BOS cost reduction of an order of magnitude or more by the mid-1980s.

  20. Solar energy and the Third World: Photovoltaic applications and their implications in rural settings for Zaire

    NASA Astrophysics Data System (ADS)

    Badibanga, Maurice Kalombay

    Purpose. The purpose of this study was to explore and analyze the level of development attained by flat-plate photovoltaic systems operating around the world and to consider the possibility of using them as an energy solution for the rural areas of Zaire. Methodology. The study was conceived to answer research questions in the following areas: (1) Zaire's overall energy situation; (2) status of photovoltaic applications and their performance in other countries; (3) how the information from this study can be applied toward a possible solution of the energy problem in rural areas of Zaire. The Dual Case Study Method was the mainstay for data and information analysis, based principally on two plants: Tangaye Village PV in Burkina Faso and Kaw Village in French Guiana. Focused Synthesis was the main strategy used to gather the information and data. The analysis of information conveyed an idea of the level of technology readiness for flat-plate photovoltaics and the direction in which future research is headed. Findings and conclusions. The study found that (1) Zaire's rural areas (70 percent of the total population) are deficient in commercial energy provision, when compared to other countries; and (2) government policies, at the time the study took place, favored big projects which benefited mostly urban settings. The rural areas could benefit from photovoltaics, due to its modular and stand-alone characteristics, if it can be afforded by the government. Zaire's geographical position is conducive to successful implementation of the PV program, and is similar to the Tangaye and Kaw situations. Recommendations. (1) The government of Zaire should seriously assess its rural energy needs and consider photovoltaics as an energy solution. (2) Research and development work in the area of energy should be encouraged in the institutions of higher learning in Zaire, where efforts should be made to keep abreast of energy technology updates in developed countries. (3) Systems that

  1. A low-power photovoltaic system with energy storage for radio communications: Description and design methodology

    NASA Technical Reports Server (NTRS)

    Chapman, C. P.; Chapman, P. D.; Lewison, A. H.

    1982-01-01

    A low power photovoltaic system was constructed with approximately 500 amp hours of battery energy storage to provide power to an emergency amateur radio communications center. The system can power the communications center for about 72 hours of continuous nonsun operation. Complete construction details and a design methodology algorithm are given with abundant engineering data and adequate theory to allow similar systems to be constructed, scaled up or down, with minimum design effort.

  2. Quality improvement of the AC electrical energy produced by a modular inverter dedicated to photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Ternifi, T. Z.; Atik, L.; Bachir, G.; Belarbi, A. W.; Petit, P.; Aillerie, M.

    2016-07-01

    This paper presents a parallel topology of a modular photovoltaic inverter, allowing a marked improvement in the quality of the output energy signal. This is a feature of much interest in practical applications as it will produce an output signal with very low harmonic distortions. In this contribution, we describe the inverter, then the bipolar pulse width modulation (PWM) strategy, which will bevalidateby simulation. Finally, some experimental results are exposed to illustrate our work.

  3. A low-power photovoltaic system with energy storage for radio communications: description and design methodology

    SciTech Connect

    Chapman, C.P.; Chapman, P.D.

    1982-01-01

    A low power photovoltaic system was constructed with approximately 500 amp hours of battery energy storage to provide power to an emergency amateur radio communications center. The system can power the communications center for about 72 hours of continuous nonsun operation. Complete construction details and a design methodology algorithm are given with abundant engineering data and adequate theory to allow similar systems to be constructed, scaled up or down, with minimum design effort.

  4. Low-power photovoltaic system with energy storage for radio communications. Description and design methodology

    SciTech Connect

    Chapman, C.P.; Chapman, P.D.; Lewison, A.H.

    1982-01-15

    A low-power photovoltaic system was constructed with approximately 500 amp-hours of battery energy storage to provide power to an emergency amateur radio communications center. The system can power the communications center for about 72 hours of continuous no-sun operation. Complete construction details and a design methodology algorithm are given with abundant engineering data and adequate theory to allow similar systems to be constructed, scaled up or down, with minimum design effort.

  5. Power Control and Optimization of Photovoltaic and Wind Energy Conversion Systems

    NASA Astrophysics Data System (ADS)

    Ghaffari, Azad

    Power map and Maximum Power Point (MPP) of Photovoltaic (PV) and Wind Energy Conversion Systems (WECS) highly depend on system dynamics and environmental parameters, e.g., solar irradiance, temperature, and wind speed. Power optimization algorithms for PV systems and WECS are collectively known as Maximum Power Point Tracking (MPPT) algorithm. Gradient-based Extremum Seeking (ES), as a non-model-based MPPT algorithm, governs the system to its peak point on the steepest descent curve regardless of changes of the system dynamics and variations of the environmental parameters. Since the power map shape defines the gradient vector, then a close estimate of the power map shape is needed to create user assignable transients in the MPPT algorithm. The Hessian gives a precise estimate of the power map in a neighborhood around the MPP. The estimate of the inverse of the Hessian in combination with the estimate of the gradient vector are the key parts to implement the Newton-based ES algorithm. Hence, we generate an estimate of the Hessian using our proposed perturbation matrix. Also, we introduce a dynamic estimator to calculate the inverse of the Hessian which is an essential part of our algorithm. We present various simulations and experiments on the micro-converter PV systems to verify the validity of our proposed algorithm. The ES scheme can also be used in combination with other control algorithms to achieve desired closed-loop performance. The WECS dynamics is slow which causes even slower response time for the MPPT based on the ES. Hence, we present a control scheme, extended from Field-Oriented Control (FOC), in combination with feedback linearization to reduce the convergence time of the closed-loop system. Furthermore, the nonlinear control prevents magnetic saturation of the stator of the Induction Generator (IG). The proposed control algorithm in combination with the ES guarantees the closed-loop system robustness with respect to high level parameter uncertainty

  6. Single stage AC-DC converter for Galfenol-based micro-power energy harvesters

    NASA Astrophysics Data System (ADS)

    Cavaroc, Peyton; Curtis, Chandra; Naik, Suketu; Cooper, James

    2014-06-01

    Military based sensor systems are often hindered in operational deployment and/or other capabilities due to limitations in their energy storage elements. Typically operating from lithium based batteries, there is a finite amount of stored energy which the sensor can use to collect and transmit data. As a result, the sensors have reduced sensing and transmission rates. However, coupled with the latest advancements in energy harvesting, these sensors could potentially operate at standard sensing and transition rates as well as dramatically extend lifetimes. Working with the magnetostrictive material Galfenol, we demonstrate the production of enough energy to supplement and recharge a solid state battery thereby overcoming the deficiencies faced by unattended sensors. As with any vibration-based energy harvester, this solution produces an alternating current which needs to be rectified and boosted to a level conducive to recharge the storage element. This paper presents a power converter capable of efficiently converting an ultra-low AC voltage to a solid state charging voltage of 4.1VDC. While we are working with Galfenol transducers as our energy source, this converter may also be applied with any AC producing energy harvester, particularly at operating levels less than 2mW and 200mVAC.

  7. High temperature solid oxide regenerative fuel cell for solar photovoltaic energy storage

    NASA Technical Reports Server (NTRS)

    Bents, David J.

    1987-01-01

    A hydrogen-oxygen regenerative fuel cell energy storage system based on high temperature solid oxide fuel cell technology is discussed which has application to darkside energy storage for solar photovoltaics. The forward and reverse operating cycles are described, and heat flow, mass, and energy balance data are presented to characterize the system's performance and the variation of performance with changing reactant storage pressure. The present system weighs less than nickel hydrogen battery systems after 0.7 darkside operation, and it maintains a specific weight advantage over radioisotope generators for discharge periods up to 72 hours.

  8. Solar energy and job creation benefits of photovoltaics in times of high unemployment

    SciTech Connect

    Hohmeyer, O.H.

    1994-12-31

    Solar energy is normally discussed under the aspects of its medium to long term contribution to the global energy supply and its present cost. The situation is characterized by the benefits of an abundant renewable energy supply option o the one side and comparatively high internal energy production costs of solar energy on the other. Besides the environmental and health benefits of renewables not taken into account in cost comparisons, solar energy has a significantly higher job creation potential as conventional energy supply options. The paper gives an introduction into the basic methodological aspects of comparing job creation effects of different energy technologies and reports on the latest results of ongoing research on the specific effects of photovoltaics as compared to conventional electricity generation.

  9. Progress Towards the Development of a Traveling Wave Direct Energy Converter for Aneutronic Fusion Propulsion Applications

    NASA Technical Reports Server (NTRS)

    Tarditi, A. G.; Chap, A.; Wolinsky, J.; Scott, J. H.

    2015-01-01

    A coordinated experimental and theory/simulation effort has been carried out to investigate the physics of the Traveling Wave Direct Energy Converter (TWDEC), a scheme that has been proposed in the past for the direct conversion into electricity of the kinetic energy of an ion beam generated from fusion reactions. This effort has been focused in particular on the TWDEC process in the high density beam regime, thus accounting for the ion beam expansion due to its space charge.

  10. New topology for DC/DC bidirectional converter for hybrid systems in renewable energy

    NASA Astrophysics Data System (ADS)

    Lopez, Juan Carlos; Ortega, Manuel; Jurado, Francisco

    2015-03-01

    This article presents a new isolated DC/DC bidirectional converter with soft switching, using a transformer with two voltage taps and two full bridges with insulated-gate bipolar transistors (IGBTs), one on each side of the transformer to be integrated in hybrid systems of renewable energy. A large voltage conversion ratio can be achieved using this converter, in buck and booster modes. Also medium and high DC power can be converted with a good efficiency. Analysis and switching techniques have been reported. To verify the principle of operation, a laboratory prototype of 10 kW has been performed. Experimental results are presented, operating in boost mode. The switching algorithm used has been modelled in MATLAB-Simulink to generate C code. This code has been implemented in a DSP F2812, which has been used to build the prototype.