Sample records for magnetic energy conversion

  1. Optimizing Energy Conversion: Magnetic Nano-materials

    NASA Astrophysics Data System (ADS)

    McIntyre, Dylan; Dann, Martin; Ilie, Carolina C.

    2015-03-01

    We present herein the work started at SUNY Oswego as a part of a SUNY 4E grant. The SUNY 4E Network of Excellence has awarded SUNY Oswego and collaborators a grant to carry out extensive studies on magnetic nanoparticles. The focus of the study is to develop cost effective rare-earth-free magnetic materials that will enhance energy transmission performance of various electrical devices (solar cells, electric cars, hard drives, etc.). The SUNY Oswego team has started the preliminary work for the project and graduate students from the rest of the SUNY 4E team (UB, Alfred College, Albany) will continue the project. The preliminary work concentrates on analyzing the properties of magnetic nanoparticle candidates, calculating molecular orbitals and band gap, and the fabrication of thin films. SUNY 4E Network of Excellence Grant.

  2. Experimental study of energy conversion in the magnetic reconnection layer

    NASA Astrophysics Data System (ADS)

    Yamada, Masaaki

    2014-10-01

    Magnetic reconnection, in which magnetic field lines break and reconnect to change their topology, occurs throughout the universe: in solar flares, the earth's magnetosphere, star forming galaxies, and laboratory fusion plasmas. The essential feature of reconnection is that it energizes plasma particles by converting magnetic energy to particle energy; this process both accelerates and heats the plasma particles. Despite the recent advances of reconnection research, the exact mechanisms for bulk plasma heating, particle acceleration, and energy flow channels remain unresolved. In this work, the mechanisms responsible for the energization of plasma particles in the magnetic reconnection layer are investigated in the MRX device together with a quantitative evaluation of the conversion of magnetic energy to ions and electrons. A comprehensive analysis of the reconnection layer is made in terms of two-fluid physics based on the measurements of two-dimensional profiles of 1) electric potential, 2) flow vectors of electrons and ions, and 3) the electron temperature, Te and the ion temperature, Ti in the layer. It is experimentally verified that a saddle shaped electrostatic electric potential profile is formed in the reconnection plane. Ions are accelerated across the separatrices by the strong electrostatic field and enter the exhaust region where they become thermalized. Electron heating is observed to extend beyond the electron diffusion region, and non-classical heating mechanisms associated with high frequency fluctuations is found to play a role. Our quantitative analysis of the energy transport processes and energy inventory concludes that more than 50% of magnetic energy is converted to plasma particles, of which 2/3 transferred to ions and 1/3 to electrons. The results which demonstrate that conversion of magnetic energy occurs in a significantly larger region than theoretically considered before, are compared with the two-fluid simulations and the recent space measurements. Broader implication of the present results will be discussed. Supported by DOE, NASA and NSF. Collaborators; J. Yoo, J. Jara Almonte, H. Ji, R. Kulsrud, and C. Myers.

  3. Permanent magnet energy conversion machine with magnet mounting arrangement

    DOEpatents

    Hsu, John S. (Oak Ridge, TN); Adams, Donald J. (Knoxville, TN)

    1999-01-01

    A hybrid permanent magnet dc motor includes three sets of permanent magnets supported by the rotor and three sets of corresponding stators fastened to the surrounding frame. One set of magnets operates across a radial gap with a surrounding radial gap stator, and the other two sets of magnets operate off the respective ends of the rotor across respective axial gaps.

  4. Conversion of magnetic energy in the magnetic reconnection layer of a laboratory plasma

    DOE PAGESBeta

    Yamada, Masaaki; Yoo, Jongsoo; Jara-Almonte, Jonathan; Ji, Hantao; Kulsrud, Russell M.; Myers, Clayton E.

    2014-09-10

    Magnetic reconnection, in which magnetic field lines break and reconnect to change their topology, occurs throughout the universe. The essential feature of reconnection is that it energizes plasma particles by converting magnetic energy. Despite the long history of reconnection research, how this energy conversion occurs remains a major unresolved problem in plasma physics. Here we report that the energy conversion in a laboratory reconnection layer occurs in a much larger region than previously considered. The mechanisms for energizing plasma particles in the reconnection layer are identified, and a quantitative inventory of the converted energy is presented for the first timemore »in a well defined reconnection layer; 50% of the magnetic energy is converted to particle energy, 2/3 of which transferred to ions and 1/3 to electrons. Our results are compared with simulations and space measurements, for a key step toward resolving one of the most important problems in plasma physics.« less

  5. Conversion of magnetic energy in the magnetic reconnection layer of a laboratory plasma

    DOE PAGESBeta

    Yamada, Masaaki [Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States). Center for Magnetic Self-Organization; Yoo, Jongsoo [Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States). Center for Magnetic Self-Organization; Jara-Almonte, Jonathan [Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States). Center for Magnetic Self-Organization; Ji, Hantao [Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States). Center for Magnetic Self-Organization; Kulsrud, Russell M. [Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States). Center for Magnetic Self-Organization; Myers, Clayton E. [Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States). Center for Magnetic Self-Organization

    2014-09-10

    Magnetic reconnection, in which magnetic field lines break and reconnect to change their topology, occurs throughout the universe. The essential feature of reconnection is that it energizes plasma particles by converting magnetic energy. Despite the long history of reconnection research, how this energy conversion occurs remains a major unresolved problem in plasma physics. Here we report that the energy conversion in a laboratory reconnection layer occurs in a much larger region than previously considered. The mechanisms for energizing plasma particles in the reconnection layer are identified, and a quantitative inventory of the converted energy is presented for the first time in a well defined reconnection layer; 50% of the magnetic energy is converted to particle energy, 2/3 of which transferred to ions and 1/3 to electrons. Our results are compared with simulations and space measurements, for a key step toward resolving one of the most important problems in plasma physics.

  6. Conversion of magnetic energy in the magnetic reconnection layer of a laboratory plasma.

    PubMed

    Yamada, Masaaki; Yoo, Jongsoo; Jara-Almonte, Jonathan; Ji, Hantao; Kulsrud, Russell M; Myers, Clayton E

    2014-01-01

    Magnetic reconnection, in which magnetic field lines break and reconnect to change their topology, occurs throughout the universe. The essential feature of reconnection is that it energizes plasma particles by converting magnetic energy. Despite the long history of reconnection research, how this energy conversion occurs remains a major unresolved problem in plasma physics. Here we report that the energy conversion in a laboratory reconnection layer occurs in a much larger region than previously considered. The mechanisms for energizing plasma particles in the reconnection layer are identified, and a quantitative inventory of the converted energy is presented for the first time in a well-defined reconnection layer; 50% of the magnetic energy is converted to particle energy, 2/3 of which transferred to ions and 1/3 to electrons. Our results are compared with simulations and space measurements, for a key step towards resolving one of the most important problems in plasma physics. PMID:25205135

  7. Multiphysics simulation of wave energy to electric energy conversion by permanent magnet linear generator

    Microsoft Academic Search

    Mats Leijon; Hans Bernhoff; Olov Ågren; Jan Isberg; Jan Sundberg; Marcus Berg; Karl Erik Karlsson; Arne Wolfbrandt

    2005-01-01

    The possibility to use three-phase permanent magnet linear generators to convert sea wave energy into electric energy is investigated by multiphysics simulations. The results show a possibility, which needs to be further verified by experimental tests, for a future step toward a sustainable electric power production from ocean waves by using direct conversion. The results suggest that wave energy can

  8. The long term stability of magnetic liquids for energy conversion devices

    Microsoft Academic Search

    J. Popplewell; S. W. Charles; R. Chantrell

    1977-01-01

    The paper shows how ferromagnetic liquids consisting of small ferromagnetic particles dispersed in a metallic carrier fluid can be used for energy conversion. The energy conversion system is as reliable as the ferromagnetic fluid itself under operating conditions of high temperatures and magnetic fields in the region of 10,000 G. Emphasis is placed on factors affecting the stability of ferromagnetic

  9. Scaling the energy conversion rate from magnetic field reconnection to different bodies

    SciTech Connect

    Mozer, F. S.; Hull, A. [Space Sciences Laboratory, University of California, Berkeley, California 94720 (United States)

    2010-10-15

    Magnetic field reconnection is often invoked to explain electromagnetic energy conversion in planetary magnetospheres, stellar coronae, and other astrophysical objects. Because of the huge dynamic range of magnetic fields in these bodies, it is important to understand energy conversion as a function of magnetic field strength and related parameters. It is conjectured theoretically and shown experimentally that the energy conversion rate per unit area in reconnection scales as the cube of an appropriately weighted magnetic field strength divided by the square root of an appropriately weighted density. With this functional dependence, the energy release in flares on the Sun, the large and rapid variation of the magnetic flux in the tail of Mercury, and the apparent absence of reconnection on Jupiter and Saturn, may be understood. Electric fields at the perihelion of the Solar Probe Plus mission may be tens of V/m.

  10. 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.

  11. Three-phase Four-wire Autonomous Wind Energy Conversion System Using Permanent Magnet Synchronous Generator

    Microsoft Academic Search

    Puneet K. Goel; Bhim Singh; S. S. Murthy; Shailendra K. Tiwari

    2010-01-01

    This article deals with an autonomous wind energy conversion system employing a permanent magnet synchronous generator feeding three-phase four-wire local loads in stand-alone mode without using a mechanical position sensor. The proposed autonomous wind energy conversion system utilizes two back-to-back connected pulse width modulated insulated gate bipolar transistors based voltage source converters with a battery energy storage system at their

  12. Parallel Operation of Permanent Magnet Generators in Autonomous Wind Energy Conversion System

    Microsoft Academic Search

    Puneet K. Goel; B. Singh; S. S. Murthy; S. K. Tiwari

    2010-01-01

    This paper deals with a new Autonomous Wind Energy Conversion System (AWECS) employing parallel operated Permanent Magnet Synchronous Generators (PMSGs) driven by variable speed wind turbines and feeding three-phase four-wire local loads. The proposed system utilizes three Pulse Width Modulated (PWM) Insulated Gate Bipolar Transistors (IGBTs) based voltage source converters (VSCs) with a battery energy storage system (BESS) at their

  13. Performance of a power conversion system for superconducting magnetic energy storage (SMES)

    Microsoft Academic Search

    James J. Skiles; Robert L. Kustom; Ka-Pui Ko; V. Wong; Ka-Shu Ko; F. Vong; K. Klontz

    1996-01-01

    This paper presents the results of laboratory tests of a power conversion system (PCS) for superconducting magnetic energy storage (SMES) applications. The PCS uses a two-quadrant chopper and a voltage-source power converter. Operating modes of the chopper are discussed. Operation of SMES to provide independent control of real and reactive power, operation as a static VAr compensator, low frequency modulation

  14. Study of energy conversion and partitioning in the magnetic reconnection layer of a laboratory plasmaa)

    NASA Astrophysics Data System (ADS)

    Yamada, Masaaki; Yoo, Jongsoo; Jara-Almonte, Jonathan; Daughton, William; Ji, Hantao; Kulsrud, Russell M.; Myers, Clayton E.

    2015-05-01

    While the most important feature of magnetic reconnection is that it energizes plasma particles by converting magnetic energy to particle energy, the exact mechanisms by which this happens are yet to be determined despite a long history of reconnection research. Recently, we have reported our results on the energy conversion and partitioning in a laboratory reconnection layer in a short communication [Yamada et al., Nat. Commun. 5, 4474 (2014)]. The present paper is a detailed elaboration of this report together with an additional dataset with different boundary sizes. Our experimental study of the reconnection layer is carried out in the two-fluid physics regime where ions and electrons move quite differently. We have observed that the conversion of magnetic energy occurs across a region significantly larger than the narrow electron diffusion region. A saddle shaped electrostatic potential profile exists in the reconnection plane, and ions are accelerated by the resulting electric field at the separatrices. These accelerated ions are then thermalized by re-magnetization in the downstream region. A quantitative inventory of the converted energy is presented in a reconnection layer with a well-defined, variable boundary. We have also carried out a systematic study of the effects of boundary conditions on the energy inventory. This study concludes that about 50% of the inflowing magnetic energy is converted to particle energy, 2/3 of which is ultimately transferred to ions and 1/3 to electrons. Assisted by another set of magnetic reconnection experiment data and numerical simulations with different sizes of monitoring box, it is also observed that the observed features of energy conversion and partitioning do not depend on the size of monitoring boundary across the range of sizes tested from 1.5 to 4 ion skin depths.

  15. Conversion of magnetic field energy into kinetic energy in the solar wind

    NASA Technical Reports Server (NTRS)

    Whang, Y. C.

    1972-01-01

    The outflow of the solar magnetic field energy (the radial component of the Poynting vector) per steradian is inversely proportional to the solar wind velocity. It is a decreasing function of the heliocentric distance. When the magnetic field effect is included in the one-fluid model of the solar wind, the transformation of magnetic field energy into kinetic energy during the expansion process increases the solar wind velocity at 1 AU by 17 percent.

  16. Magnetic flux conversion and relaxation toward a minimum-energy state in S-1 spheromak plasmas

    SciTech Connect

    Janos, A.

    1985-09-01

    S-1 Spheromak currents and magnetic fluxes have been measured with Rogowski coils and flux loops external to the plasma. Toroidal plasma currents up to 350 kA and spheromak configuration lifetimes over 1.0 msec have been achieved at moderate power levels. The plasma formation in the S-1 Spheromak device is based on an inductive transfer of poloidal and toroidal magnetic flux from a toroidal ''flux core'' to the plasma. Formation is programmed to guide the configuration into a force-free, minimum-energy Taylor state. Properly detailed programming of the formation process is found not to be essential since plasmas adjust themselves during formation to a final equilibrium near the Taylor state. After formation, if the plasma evolves away from the stable state, then distinct relaxation oscillation events occur which restore the configuration to that stable state. The relaxation process involves reconnection of magnetic field lines, and conversion of poloidal to toroidal magnetic flux (and vice versa) has been observed and documented. The scaling of toroidal plasma current and toroidal magnetic flux in the plasma with externally applied currents is consistent with the establishment of a Taylor state after formation. In addition, the magnetic helicity is proportional to that injected from the flux core, independent of how that helicity is generated.

  17. Study of Energy Conversion and Partitioning in the Magnetic Reconnection Layer in Laboratory and Space Plasmas

    NASA Astrophysics Data System (ADS)

    Yamada, M.

    2014-12-01

    The essential feature of magnetic reconnection is that it energizes plasma particles by converting magnetic energy to particle energy [1]. This talk addresses this key unresolved question; how is magnetic energy converted to plasma kinetic energy during reconnection? The mechanisms responsible for the energization of plasma particles in the magnetic reconnection layer have been investigated in the MRX device together with quantitative evaluation of conversion of magnetic energy to ions and electrons. An analysis is made in terms of two-fluid physics based on the measurements of two-dimensional profiles of 1) electric potential, 2) flow vectors of electrons and ions, and 3) the electron temperature, Te and the ion temperature, Ti in the layer [2,3]. It is shown that more than 50 % of magnetic energy is converted to plasma particles, of which 2/3 transferred to ions and 1/3 to electrons, at a remarkably fast speed (~0.2VA) in the reconnection layer [3]. In a reconnection region of effectively similar size in the Earth's magnetotail, the energy partition was recently measured during multiple passages of the Cluster satellites [4]. The half length of the tail reconnection layer (L) was estimated to be 2000-4000 km namely 3-6di; the scale length is very similar to the MRX case, L ~ 3di. Reconnection in the magneto-tail is driven by an external force, i.e., the solar wind, and the boundary conditions are very similar to the MRX setup. The observed energy partition is notably similar, namely, more than 50% of the magnetic energy flux is converted to the particle energy flux, which is dominated by the ion enthalpy flux, with smaller contributions from the electron enthalpy and heat flux. A broad implication will be discussed. Work supported by DOE, NASA, and NSF. Fig.1: Measured ion flow vectors in the reconnection plane with measured 2-D profile of the plasma potential ?_p. The thin lines are measured poloidal flux counters.[1] M. Yamada, R. Kulsrud, & H. Ji, Rev. Mod. Phys. 82, 603-664 (2010). [2] J. Yoo et al, Phys. Plasmas 21, 055706 (2014), [3] M. Yamada et al, Nature Communications (2014) [4] J. P. Eastwood et al., Phys. Rev. Lett. 110, 225001 (2013)

  18. Direct Conversion of Energy.

    ERIC Educational Resources Information Center

    Corliss, William R.

    This publication is one of a series of information booklets for the general public published by the United States Atomic Energy Commission. Direct energy conversion involves energy transformation without moving parts. The concepts of direct and dynamic energy conversion plus the laws governing energy conversion are investigated. Among the topics…

  19. Surface Magnetic Hyperfine Interactions in Fe2O3 Determined by Energy-Resolved Conversion-Electron Mössbauer Spectroscopy

    Microsoft Academic Search

    T. Yang; A. Krishnan; N. Benczer-Koller; G. Bayreuther

    1982-01-01

    The magnetic hyperfine field at 57Fe in uncharacterized Fe2O3 films has been measured as a function of depth by a new technique combining high-energy-resolution conversion-electron spectroscopy with Mössbauer resonance absorption. The hyperfine field H(t) was mapped as a function of depth t into the sample. It reaches the bulk value 51.761 +\\/- 0.008 T at a depth of t0<=18+\\/-3 Å

  20. Energy conversion alternatives study

    NASA Technical Reports Server (NTRS)

    Shure, L. T.

    1979-01-01

    Comparison of coal based energy systems is given. Study identifies and compares various advanced energy conversion systems using coal or coal derived fuels for baselaoad electric power generation. Energy Conversion Alternatives Study (ECAS) reports provede government, industry, and general public with technically consistent basis for comparison of system's options of interest for fossilfired electric-utility application.

  1. Photochemical Energy Conversion.

    ERIC Educational Resources Information Center

    Batschelet, William H.; George, Arnold

    1986-01-01

    Describes procedures for two demonstrations: (1) photochemical energy conversion using ferric oxalate actinometry and (2) liquification of gases using Freon 114. Safety precautions are given for both demonstrations, as are procedures and material specifications. (JM)

  2. Algae Harvest Energy Conversion

    Microsoft Academic Search

    Yung-Tse Hung; O. Sarafadeen Amuda; A. Olanrewaju Alade; I. Adekunle Amoo; Stephen Tiong-Lee Tay; Kathleen Hung Li

    \\u000a Algae harvest energy conversion to biofuel technology is a promising alternative to fossil fuel that has inherent pollution\\u000a attachment. With present resources available for the microalgae mass production and hence, high oil yield, microalgal can\\u000a sufficiently be a new source of renewable energy to replace the fossil fuels. In this chapter, algae description, composition,\\u000a cultivation, its conversion to biofuel, and

  3. High-energy neutrino conversion into an electron-W pair in a magnetic field and its contribution to neutrino absorption

    Microsoft Academic Search

    Andrea Erdas; Marcello Lissia

    2003-01-01

    We calculate the conversion rate of high-energy neutrinos propagating in a constant magnetic field into an electron-W pair (nu-->W+e) from the imaginary part of the neutrino self-energy. Using the exact propagators in a constant magnetic field, the neutrino self-energy has been calculated to all orders in the field within the Weinberg-Salam model. We obtain a compact formula in the limit

  4. Laser energy conversion

    NASA Technical Reports Server (NTRS)

    Jalufka, N. W.

    1989-01-01

    The conversion of laser energy to other, more useful, forms is an important element of any space power transmission system employing lasers. In general the user, at the receiving sight, will require the energy in a form other than laser radiation. In particular, conversion to rocket power and electricity are considered to be two major areas where one must consider various conversion techniques. Three systems (photovoltaic cells, MHD generators, and gas turbines) have been identified as the laser-to-electricity conversion systems that appear to meet most of the criteria for a space-based system. The laser thruster also shows considerable promise as a space propulsion system. At this time one cannot predict which of the three laser-to-electric converters will be best suited to particular mission needs. All three systems have some particular advantages, as well as disadvantages. It would be prudent to continue research on all three systems, as well as the laser rocket thruster. Research on novel energy conversion systems, such as the optical rectenna and the reverse free-electron laser, should continue due to their potential for high payoff.

  5. Electromagnetic energy conversion at reconnection fronts.

    PubMed

    Angelopoulos, V; Runov, A; Zhou, X-Z; Turner, D L; Kiehas, S A; Li, S-S; Shinohara, I

    2013-09-27

    Earth's magnetotail contains magnetic energy derived from the kinetic energy of the solar wind. Conversion of that energy back to particle energy ultimately powers Earth's auroras, heats the magnetospheric plasma, and energizes the Van Allen radiation belts. Where and how such electromagnetic energy conversion occurs has been unclear. Using a conjunction between eight spacecraft, we show that this conversion takes place within fronts of recently reconnected magnetic flux, predominantly at 1- to 10-electron inertial length scale, intense electrical current sheets (tens to hundreds of nanoamperes per square meter). Launched continually during intervals of geomagnetic activity, these reconnection outflow flux fronts convert ~10 to 100 gigawatts per square Earth radius of power, consistent with local magnetic flux transport, and a few times 10(15) joules of magnetic energy, consistent with global magnetotail flux reduction. PMID:24072917

  6. Energy-mass conversion

    NSDL National Science Digital Library

    Lawrence Berkeley National Laboratory. Particle Data Group

    2002-01-01

    How do physicists make new particles? In this page of a particle physics tutorial, students are introduced to the concept of converting kinetic energy to mass. Students read that low-mass particles placed into an accelerator can be smashed together to produce more massive particles through the conversion of energy to mass. They see an example in which two pieces of fruit are accelerated and smashed, and additional types of fruit are produced. Copyright 2005 Eisenhower National Clearinghouse

  7. Magnetohydrodynamics of atmospheric transients. IV - Nonplane two-dimensional analyses of energy conversion and magnetic field evolution. [during corona following solar flare

    NASA Technical Reports Server (NTRS)

    Wu, S. T.; Nakagawa, Y.; Han, S. M.; Dryer, M.

    1982-01-01

    The evolution of the magnetic field and the manner of conversion of thermal energy into different forms in the corona following a solar flare are investigated by means of a nonplane magnetohydrodynamic (MHD) analysis. All three components of magnetic field and velocity are treated in a physically self-consistent manner, with all physical variables as functions of time (t) and two spatial coordinates (r, theta). The difference arising from the initial magnetic field, either twisted (force-free) or non-twisted (potential), is demonstrated. Consideration is given to two initial field topologies (open vs. closed). The results demonstrate that the conversion of magnetic energy is faster for the case of the initially twisted (force-free) field than for the initially untwisted (potential) field. In addition, the twisted field is found to produce a complex structure of the density enhancements.

  8. Energy conversion and storage program

    Microsoft Academic Search

    E. J. Cairns

    1992-01-01

    The Energy Conversion and Storage Program applies chemistry and materials science principles to solve problems in: (1) production of new synthetic fuels; (2) development of high-performance rechargeable batteries and fuel cells; (3) development of advanced thermochemical processes for energy conversion; (4) characterization of complex chemical processes; and (5) application of novel materials for energy conversion and transmission. Projects focus on

  9. Photoelectrochemical solar energy conversion

    NASA Astrophysics Data System (ADS)

    Memming, Rüdiger

    In the present paper the progress in the field of solar energy conversion for the production of electricity and storable chemical fuels during the last decade is reviewed. The current-potential behavior of regenerative photovoltaic cells are derived and related to charge transfer processes at the solid/liquid interface. Various cells are critically analyzed in view of their stability and conversion efficiency. A number of factors limiting the photovoltage are discussed in terms of a stabilization mechanism, trapping of minority carriers at the interface and the forward dark current. Concerning the production of chemical fuels the photocleavage of water and hydrogen sulfide, the reduction of carbon dioxide and the formation of ammonia is evaluated. The main emphasis is laid here on catalytic processes at semiconductor electrodes and particles. The principle function of catalysts being deposited on extended electrodes and particles are discussed in detail.

  10. Thermal Energy Conversion Branch

    NASA Technical Reports Server (NTRS)

    Bielozer, Matthew C.; Schreiber, Jeffrey, G.; Wilson, Scott D.

    2004-01-01

    The Thermal Energy Conversion Branch (5490) leads the way in designing, conducting, and implementing research for the newest thermal systems used in space applications at the NASA Glenn Research Center. Specifically some of the most advanced technologies developed in this branch can be broken down into four main areas: Dynamic Power Systems, Primary Solar Concentrators, Secondary Solar Concentrators, and Thermal Management. Work was performed in the Dynamic Power Systems area, specifically the Stirling Engine subdivision. Today, the main focus of the 5490 branch is free-piston Stirling cycle converters, Brayton cycle nuclear reactors, and heat rejection systems for long duration mission spacecraft. All space exploring devices need electricity to operate. In most space applications, heat energy from radioisotopes is converted to electrical power. The Radioisotope Thermoelectric Generator (RTG) already supplies electricity for missions such as the Cassini Spacecraft. The focus of today's Stirling research at GRC is aimed at creating an engine that can replace the RTG. The primary appeal of the Stirling engine is its high system efficiency. Because it is so efficient, the Stirling engine will significantly reduce the plutonium fuel mission requirements compared to the RTG. Stirling is also being considered for missions such as the lunar/Mars bases and rovers. This project has focused largely on Stirling Engines of all types, particularly the fluidyne liquid piston engine. The fluidyne was developed by Colin D. West. This engine uses the same concepts found in any type of Stirling engine, with the exception of missing mechanical components. All the working components are fluid. One goal was to develop and demonstrate a working Stirling Fluidyne Engine at the 2nd Annual International Energy Conversion Engineering Conference in Providence, Rhode Island.

  11. Energy Conversion and Storage Program

    Microsoft Academic Search

    E. J. Cairns

    1993-01-01

    This report is the 1992 annual progress report for the Energy Conversion and Storage Program, a part of the Energy and Environment Division of the Lawrence Berkeley Laboratory. Work described falls into three broad areas: electrochemistry; chemical applications; and materials applications. The Energy Conversion and Storage Program applies principles of chemistry and materials science to solve problems in several areas:

  12. Review of betavoltaic energy conversion

    Microsoft Academic Search

    Larry C. Olsen

    1993-01-01

    Betavoltaic energy conversion refers to the generation of power by coupling a beta source to a semiconductor junction device. The theory of betavoltaic energy conversion and some past studies of the subject are briefly reviewed. Calculations of limiting efficiencies for semiconductor cells versus bandgap are presented along with specific studies for Pm-147 and Ni-63 fueled devices. The approach used for

  13. Energy conversion system

    SciTech Connect

    Wang, F.E.

    1981-06-30

    A thermal-mechanical energy converting device is disclosed that has at least two rotatably supported wheels and with one or more endless transmission elements of a material having a memory effect capable in the bending mode of converting thermal energy into mechanical energy when heated from a temperature below its transition temperature to a temperature above its transition temperature; the transmission elements serve to drive one wheel from the other wheel upon application of thermal energy to the transmission elements, whereby the thermal energy is transferred from the other wheel to the transmission elements over at least a major portion of the circumferential contact of the transmission elements with the other wheel.

  14. Review of betavoltaic energy conversion

    NASA Astrophysics Data System (ADS)

    Olsen, Larry C.

    1993-05-01

    Betavoltaic energy conversion refers to the generation of power by coupling a beta source to a semiconductor junction device. The theory of betavoltaic energy conversion and some past studies of the subject are briefly reviewed. Calculations of limiting efficiencies for semiconductor cells versus bandgap are presented along with specific studies for Pm-147 and Ni-63 fueled devices. The approach used for fabricating Pm-147 fueled batteries by the author in the early 1970's is reviewed. Finally, the potential performance of advanced betavoltaic power sources is considered.

  15. Solar energy conversion.

    SciTech Connect

    Crabtree, G. W.; Lewis, N. S.; Materials Science Division; Cal Tech

    2007-03-01

    The Sun provides Earth with a staggering amount of energy - enough to power the great oceanic and atmospheric currents, the cycle of evaporation and condensation that brings fresh water inland and drives river flow, and the typhoons, hurricanes, and tornadoes that so easily destroy the natural and built landscape. The San Francisco earthquake of 1906, with magnitude 7.8, released an estimated 10{sup 17} joules of energy, the amount the Sun delivers to Earth in one second. Earth's ultimate recoverable resource of oil, estimated at 3 trillion barrels, contains 1.7 x 10{sup 22} joules of energy, which the Sun supplies to Earth in 1.5 days. The amount of energy humans use annually, about 4.6 x 10{sup 20} joules, is delivered to Earth by the Sun in one hour. The enormous power that the Sun continuously delivers to Earth, 1.2 x 10{sup 5} terawatts, dwarfs every other energy source, renewable or nonrenewable. It dramatically exceeds the rate at which human civilization produces and uses energy, currently about 13 TW.

  16. Solar energy conversion

    Microsoft Academic Search

    George W. Crabtree; Nathan S. Lewis

    2007-01-01

    The Sun provides Earth with a staggering amount of energy - enough to power the great oceanic and atmospheric currents, the cycle of evaporation and condensation that brings fresh water inland and drives river flow, and the typhoons, hurricanes, and tornadoes that so easily destroy the natural and built landscape. The San Francisco earthquake of 1906, with magnitude 7.8, released

  17. Hydrothermal Energy Conversion Technology

    Microsoft Academic Search

    David W. Robertson; Raymond J. LaSala

    1992-01-01

    The goal of the Hydrothermal Program is to develop concepts which allow better utilization of geothermal energy to reduce the life-cycle cost of producing electricity from liquid-dominated, hydrothermal resources. Research in the program is currently ongoing in three areas: (1) Heat Cycle Research, which is looking at methods to increase binary plant efficiencies; (2) Materials Development, which is developing materials

  18. Electrochemistry for Energy Conversion

    NASA Astrophysics Data System (ADS)

    O'Hayre, Ryan

    2010-10-01

    Imagine a laptop computer that runs for 30 hours on a single charge. Imagine a world where you plug your house into your car and power lines are a distant memory. These dreams motivate today's fuel cell research. While some dreams (like powering your home with your fuel cell car) may be distant, others (like a 30-hour fuel cell laptop) may be closer than you think. If you are curious about fuel cells---how they work, when you might start seeing them in your daily life--- this talk is for you. Learn about the state-of-the art in fuel cells, and where the technology is likely to be headed in the next 20 years. You'll also be treated to several ``behind-the scenes'' glimpses of cutting-edge research projects under development in the Renewable Energy Materials Center at the Colorado School of Mines--- projects like an ``ionic transistor'' that works with protons instead of electrons, and a special ceramic membrane material that enables the ``uphill'' diffusion of steam. Associate Professor Ryan O'Hayre's laboratory at the Colorado School of Mines develops new materials and devices to enable alternative energy technologies including fuel cells and solar cells. Prof. O'Hayre and his students collaborate with the Colorado Fuel Cell Center, the Colorado Center for Advanced Ceramics, the Renewable Energy Materials Science and Engineering Center, and the National Renewable Energy Laboratory.[4pt] In collaboration with Ann Deml, Jianhua Tong, Svitlana Pylypenko, Archana Subramaniyan, Micahael Sanders, Jason Fish, Annette Bunge, Colorado School of Mines.

  19. Observation of Thermoacoustic Energy Conversion

    Microsoft Academic Search

    Yusuke Tashiro; Tetsushi Biwa; Taichi Yazaki

    2008-01-01

    In order to understand thermoacoustic phenomena from a point of view of thermodynamics, oscillating pressure, velocity and temperature were measured in the tube having a temperature gradient. By converting the measured Eulerian quantities to the Lagrangian quantities associated with a given gas parcel, we determined the local energy conversion rate per unit volume and time. The obtained data demonstrate the

  20. Electrochemical Processes in Energy Conversion and Storage

    Microsoft Academic Search

    Rainer Bussar; Ulrich Stimming

    At present generation of electrical energy is mainly based on the conversion of fossil fuels such as coal, oil and natural gas within thermal cycle power plants. Although the overall conversion efficiency of thermal power plants was significantly increased, electrochemical energy conversion processes have the potential to further optimize conversion efficiency. Especially high temperature fuel cells, based on solid oxide-

  1. Materials for thermoelectric energy conversion

    NASA Technical Reports Server (NTRS)

    Wood, C.

    1988-01-01

    The field of thermoelectric energy conversion is reviewed from both a theoretical and an experimental standpoint. The basic theory is introduced and the thermodynamic and solid state views are compared. An overview of the development of thermoelectric materials is presented with particular emphasis being placed on the most recent developments in high-temperature semiconductors. A number of possible device applications are discussed and the successful use and suitability of these devices for space power is manifest.

  2. Radiation energy conversion in space

    Microsoft Academic Search

    K. W. Billman

    1979-01-01

    Topics discussed at the third NASA conference on radiant energy conversion are reviewed. The unconcentrated-photovoltaic-generation version of a solar power satellite is described, noting that it will consist of a 21.3 x 5.3-sq-km silicon-solar-cell array expected to provide 17 Gw of electrical power, with 1 km in diam transmitters oriented to beam 2.45 GHz microwave power to two receiving\\/rectifying 'rectennas'

  3. Biomass conversion processes for energy and fuels

    NASA Astrophysics Data System (ADS)

    Sofer, S. S.; Zaborsky, O. R.

    The book treats biomass sources, promising processes for the conversion of biomass into energy and fuels, and the technical and economic considerations in biomass conversion. Sources of biomass examined include crop residues and municipal, animal and industrial wastes, agricultural and forestry residues, aquatic biomass, marine biomass and silvicultural energy farms. Processes for biomass energy and fuel conversion by direct combustion (the Andco-Torrax system), thermochemical conversion (flash pyrolysis, carboxylolysis, pyrolysis, Purox process, gasification and syngas recycling) and biochemical conversion (anaerobic digestion, methanogenesis and ethanol fermentation) are discussed, and mass and energy balances are presented for each system.

  4. Clean Fossil Energy Conversion Processes

    NASA Astrophysics Data System (ADS)

    Fan, L.-S.

    2007-03-01

    Absolute and per-capita energy consumption is bound to increase globally, leading to a projected increase in energy requirements of 50% by 2020. The primary source for providing a majority of the energy will continue to be fossil fuels. However, an array of enabling technologies needs to be proven for the realization of a zero emission power, fuel or chemical plants in the near future. Opportunities to develop new processes, driven by the regulatory requirements for the reduction or elimination of gaseous and particulate pollutant abound. This presentation describes the chemistry, reaction mechanisms, reactor design, system engineering, economics, and regulations that surround the utilization of clean coal energy. The presentation will cover the salient features of the fundamental and process aspects of the clean coal technologies in practice as well as in development. These technologies include those for the cleaning of SO2, H2S, NOx, and heavy metals, and separation of CO2 from the flue gas or the syngas. Further, new combustion and gasification processes based on the chemical looping concepts will be illustrated in the context of the looping particle design, process heat integration, energy conversion efficiency, and economics.

  5. The upper limit to solar energy conversion

    Microsoft Academic Search

    Sean E. Wright; David S. Scott; James B. Haddow; Marc A. Rosen

    2000-01-01

    Petela carried out research to determine the maximum ideal theoretical work output obtainable from BR independent of any conversion device. However, omnicolor conversion is considered by many to be the ideal theoretical process for solar energy conversion. Petela's result for blackbody radiation (BR) exergy is often thought to be of little importance because it appears to neglect fundamental theoretical issues

  6. Light harvesting for quantum solar energy conversion

    Microsoft Academic Search

    Tomas Markvart

    2000-01-01

    Despite wide structural and functional differences, the laws that govern quantum solar energy conversion to chemical energy or electricity share many similarities. In the photosynthetic membrane, in common with semiconductor solar cells, the conversion process proceeds from the creation of electron–hole pairs by a photon of light, followed by charge separation to produce the required high-energy product. In many cases,

  7. A novel sun engine for solar to electrical energy conversion

    SciTech Connect

    Rincon, E.; Velasco, E.; Cordova, G.; Ruiz, R. [UAEM, Toluca (Mexico). Facultad de Ingenieria

    1995-12-31

    A new concept of solar engine (Rincon, 1994) is presented based on the trends of energy conversion and the new development of materials looking for the highest efficiency of conversion and lowest manufacturing cost. Passive elements implemented are one of the new energy conversion concepts: a stationary CPC type collector (18{degree} half acceptance angle), a radial magnetization pattern of magnetic bearings (made of SmCo), and a passive coolant recirculating system removing the internal irreversibilities. The elimination of friction, electrical resistance, spontaneous expansion and compression, magnetic drag, scattering of beam radiation, finite pressure drop and finite temperature differences are key elements of this engine. Its main novelty consists of an adiabatic, frictionless rotor integrating an inertial propulsion engine purely electromechanical and electromagnetic radiation as two modes of propulsion for rotation.

  8. Magnetic Materials in sustainable energy

    NASA Astrophysics Data System (ADS)

    Gutfleisch, Oliver

    2012-02-01

    A new energy paradigm, consisting of greater reliance on renewable energy sources and increased concern for energy efficiency in the total energy lifecycle, has accelerated research in energy-related technologies. Due to their ubiquity, magnetic materials play an important role in improving the efficiency and performance of devices in electric power generation, conversion and transportation. Magnetic materials are essential components of energy applications (i.e. motors, generators, transformers, actuators, etc.) and improvements in magnetic materials will have significant impact in this area, on par with many ``hot'' energy materials efforts. The talk focuses on the state-of-the-art hard and soft magnets and magnetocaloric materials with an emphasis on their optimization for energy applications. Specifically, the impact of hard magnets on electric motor and transportation technologies, of soft magnetic materials on electricity generation and conversion technologies, and of magnetocaloric materials for refrigeration technologies, will be discussed. The synthesis, characterization, and property evaluation of the materials, with an emphasis on structure-property relationships, will be examined in the context of their respective markets as well as their potential impact on energy efficiency. Finally, considering future bottle-necks in raw materials and in the supply chain, options for recycling of rare-earth metals will be analyzed.ootnotetextO. Gutfleisch, J.P. Liu, M. Willard, E. Bruck, C. Chen, S.G. Shankar, Magnetic Materials and Devices for the 21st Century: Stronger, Lighter, and More Energy Efficient (review), Adv. Mat. 23 (2011) 821-842.

  9. Magnetic energy flow in the solar wind.

    NASA Technical Reports Server (NTRS)

    Modisette, J. L.

    1972-01-01

    Discussion of the effect of rotation (tangential flow) of the solar wind on the conclusions of Whang (1971) suggesting an increase in the solar wind velocity due to the conversion of magnetic energy to kinetic energy. It is shown that the effect of the rotation of the sun on the magnetic energy flow results in most of the magnetic energy being transported by magnetic shear stress near the sun.

  10. The Conversion of Waste to Energy 

    E-print Network

    John, T.; Cheek, L.

    1980-01-01

    Almost every industrial operation produces some combustible waste, but conversion of this to useful energy is often more difficult than with other energy recovery projects and requires careful attention to design, operating and maintaining...

  11. Energy Conversion & Storage Program, 1993 annual report

    SciTech Connect

    Cairns, E.J.

    1994-06-01

    The Energy Conversion and Storage Program applies chemistry and materials science principles to solve problems in: production of new synthetic fuels; development of high-performance rechargeable batteries and fuel cells; development of high-efficiency thermochemical processes for energy conversion; characterization of complex chemical processes and chemical species; and the study and application of novel materials for energy conversion and transmission. Projects focus on transport-process principles, chemical kinetics, thermodynamics, chemical kinetics, thermodynamics, separation processes, organic and physical chemistry, novel materials, and advanced methods of analysis.

  12. Energy Conversion in Natural and Artificial Photosynthesis

    PubMed Central

    McConnell, Iain; Li, Gonghu; Brudvig, Gary W.

    2010-01-01

    Summary Modern civilization is dependent upon fossil fuels, a nonrenewable energy source originally provided by the storage of solar energy. Fossil fuel dependence has severe consequences including energy security issues and greenhouse gas emissions. The consequences of fossil fuel dependence could be avoided by fuel-producing artificial systems that mimic natural photosynthesis, directly converting solar energy to fuel. This review describes the three key components of solar energy conversion in photosynthesis: light harvesting, charge separation, and catalysis. These processes are compared in natural and artificial systems. Such a comparison can assist in understanding the general principles of photosynthesis and in developing working devices including photoelectrochemical cells for solar energy conversion. PMID:20534342

  13. Solar-wind energy conversion system

    Microsoft Academic Search

    1982-01-01

    A combined solar-wind energy conversion system in which the combined effects of solar and wind energy are utilized in raising water from a lower to an upper water storage tank to increase its potential energy for generation of electricity. Incoming solar energy heats water to form steam which is temporarily stored. The stored steam is vented to one of first

  14. Solar-wind energy conversion system

    Microsoft Academic Search

    1984-01-01

    A combined solar-wind energy conversion system in which the combined effects of solar and wind energy are utilized in raising water from a lower to an upper water storage tank to increase its potential energy for generation of electricity. Incoming solar energy heats water to form steam which is temporarily stored. The stored steam is vented to one of first

  15. Conversion of radiant light energy in photobioreactors

    Microsoft Academic Search

    J. F. Cornet; C. G. Dussap; J. B. Gros

    1994-01-01

    The conversion of radiant light energy into chemical affinity by microorganisms in photobioreactors is examined. The kinetics of entropy production in the system is theoretically established from entropy and energy balances for the material and photonic phases in the reactor. A negative chemical affinity term compensated for by a radiant energy term at a higher level of energy characterizes photosynthetic

  16. Hybrid staging of geothermal energy conversion process

    SciTech Connect

    Steidel, R.F. Jr.

    1984-05-07

    Progress in the demonstration of the feasibility of hybrid staging in geothermal energy conversion is described, particularly processes involving the Lysholm engine. The performance limitations of the Lysholm engine were studied. (MHR)

  17. Thermionic Energy Conversion (TEC) topping thermoelectrics

    NASA Technical Reports Server (NTRS)

    Morris, J. F.

    1981-01-01

    Performance expectations for thermionic and thermoelectric energy conversion systems are reviewed. It is noted that internal radiation effects diminish thermoelectric figures of merit significantly at 1000 K and substantially at 2000 K; the effective thermal conductivity contribution of intrathermoelectric radiative dissipation increases with the third power of temperature. It is argued that a consideration of thermoelectric power generation with high temperature heat sources should include utilization of thermionic energy conversion (TEC) topping thermoelectrics. However TEC alone or TEC topping more efficient conversion systems like steam or gas turbines, combined cycles, or Stirling engines would be more desirable generally.

  18. Chemistry of energy conversion and storage.

    PubMed

    Su, Dang Sheng

    2012-03-12

    Energy is a big issue in our society, fueled by growing awareness of the finite resources of liquid fossil fuels and the noticeable changes in our climate resulting from its consumption. The general consensus is that there should be a well-considered roadmap towards a future energy scenario, with the replacement of fossil energy by renewable energies as the final goal. This "Chemistry of Energy Conversion and Storage" issue contains papers dealing with the chemistry behind renewable energies. PMID:22407997

  19. Ocean Wave Energy Conversion - A Survey

    Microsoft Academic Search

    A. Muetze; J. G. Vining

    2006-01-01

    Ocean energy conversion has been of interest for many years. Recent developments such as concern over global warming have renewed interest in the topic. This paper gives a systematic and comprehensive overview of wave energy converters (WEC) as opposed to ocean current energy converters. The point absorber and oscillating water column WEC devices are addressed with regards to commercial prospects,

  20. Mode Conversion of Solar p-Modes in Non-Vertical Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Crouch, A. D.; Cally, P. S.

    2005-03-01

    Sunspots absorb and scatter incident f- and p-modes. Until recently, the responsible absorption mechanism was uncertain. The most promising explanation appears to be mode conversion to slow magnetoacoustic-gravity waves, which carry energy down the magnetic field lines into the interior. In vertical magnetic field, mode conversion can adequately explain the observed f-mode absorption, but is too inefficient to account for the absorption of p-modes. In the first paper of the present series we calculated the efficiency of fast-to-slow magnetoacoustic-gravity wave conversion in uniform non-vertical magnetic fields. We assumed two-dimensional propagation, where the Alfvén waves decouple. In comparison to vertical field, it was found that mode conversion is significantly enhanced in moderately inclined fields, especially at higher frequencies. Using those results, Cally, Crouch, and Braun showed that the resultant p-mode absorption produced by simple sunspot models with non-vertical magnetic fields is ample to explain the observations. In this paper, we further examine mode conversion in non-vertical magnetic fields. In particular, we consider three-dimensional propagation, where the fast and slow magnetoacoustic-gravity waves and the Alfvén waves are coupled. Broadly speaking, the p-mode damping rates are not substantially different to the two-dimensional case. However, we do find that the Alfvén waves can remove similar quantities of energy to the slow MAG waves.

  1. Electromagnetic wave energy conversion research

    NASA Technical Reports Server (NTRS)

    Bailey, R. L.; Callahan, P. S.

    1975-01-01

    Known electromagnetic wave absorbing structures found in nature were first studied for clues of how one might later design large area man-made radiant-electric converters. This led to the study of the electro-optics of insect dielectric antennae. Insights were achieved into how these antennae probably operate in the infrared 7-14um range. EWEC theoretical models and relevant cases were concisely formulated and justified for metal and dielectric absorber materials. Finding the electromagnetic field solutions to these models is a problem not yet solved. A rough estimate of losses in metal, solid dielectric, and hollow dielectric waveguides indicates future radiant-electric EWEC research should aim toward dielectric materials for maximum conversion efficiency. It was also found that the absorber bandwidth is a theoretical limitation on radiant-electric conversion efficiency. Ideally, the absorbers' wavelength would be centered on the irradiating spectrum and have the same bandwith as the irradiating wave. The EWEC concept appears to have a valid scientific basis, but considerable more research is needed before it is thoroughly understood, especially for the complex randomly polarized, wide band, phase incoherent spectrum of the sun. Specific recommended research areas are identified.

  2. High-Temperature Thermoelectric Energy Conversion

    NASA Technical Reports Server (NTRS)

    Wood, C.

    1987-01-01

    Theory of thermoelectric energy conversion at high temperatures and status of research on conversion materials reviewed in report. Shows highest values of thermoelectric figure of merit, Z, found in semiconductor materials. Semiconductors keep wide choice of elements and compounds. Electrical properties tailored to particular application by impurity doping and control of stoichiometry. Report develops definition of Z useful for comparing materials and uses it to evaluate potentials of different classes of materialsmetals, semiconductors, and insulators.

  3. SPS Energy Conversion Power Management Workshop

    NASA Astrophysics Data System (ADS)

    1980-06-01

    Energy technology concerning photovoltaic conversion, solar thermal conversion systems, and electrical power distribution processing is discussed. The manufacturing processes involving solar cells and solar array production are summarized. Resource issues concerning gallium arsenides and silicon alternatives are reported. Collector structures for solar construction are described and estimates in their service life, failure rates, and capabilities are presented. Theories of advanced thermal power cycles are summarized. Power distribution system configurations and processing components are presented.

  4. SPS Energy Conversion Power Management Workshop

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Energy technology concerning photovoltaic conversion, solar thermal conversion systems, and electrical power distribution processing is discussed. The manufacturing processes involving solar cells and solar array production are summarized. Resource issues concerning gallium arsenides and silicon alternatives are reported. Collector structures for solar construction are described and estimates in their service life, failure rates, and capabilities are presented. Theories of advanced thermal power cycles are summarized. Power distribution system configurations and processing components are presented.

  5. Direct Energy Conversion, a current awareness bulletin

    NASA Astrophysics Data System (ADS)

    1982-08-01

    This bulletin contains 94 abstracts and bibliographic citations of scientific and technical reports, journal articles, conference proceedings, patents, books, and other published literature on all aspects of direct energy conversion. A subject index and a report number index are provided. This information is selected from the DOE/TIC Energy Data Base.

  6. Photon-Axion conversions in transversely inhomogeneous magnetic fields

    E-print Network

    Javier Redondo

    2010-03-01

    We compute the photon-axion conversion probability in an external magnetic field with a strong transverse gradient in the eikonal approximation for plane waves. We find it typically smaller than a comparable uniform case. Some insights into the phenomenon of photon-axion splitting are given.

  7. Solar energy conversion through photosynthesis

    Microsoft Academic Search

    R. K. Clayton

    1977-01-01

    Energy sources of possible quantitative significance which are directly or indirectly of contemporary solar origin are considered, taking into account wind-powered electric generators, ocean thermal gradients, direct solar heating, variations of agriculture, photosynthetic hydrogen production, and photoelectric devices. The most practical schemes for capturing solar energy appear at this time to be directly heating and harnessing the wind. Silicon photovoltaic

  8. A new wind energy conversion system

    NASA Technical Reports Server (NTRS)

    Smetana, F. O.

    1975-01-01

    It is presupposed that vertical axis wind energy machines will be superior to horizontal axis machines on a power output/cost basis and the design of a new wind energy machine is presented. The design employs conical cones with sharp lips and smooth surfaces to promote maximum drag and minimize skin friction. The cones are mounted on a vertical axis in such a way as to assist torque development. Storing wind energy as compressed air is thought to be optimal and reasons are: (1) the efficiency of compression is fairly high compared to the conversion of mechanical energy to electrical energy in storage batteries; (2) the release of stored energy through an air motor has high efficiency; and (3) design, construction, and maintenance of an all-mechanical system is usually simpler than for a mechanical to electrical conversion system.

  9. Hydraulic wind energy conversion system

    SciTech Connect

    Not Available

    1981-07-01

    The purpose of this research was to design, build and test a hydraulic wind energy system. This design used a three bladed turbine, which drove a hydraulic pump. The energy is transmitted from the pump through a long hose and into a hydraulic motor, where the energy is used. This wind system was built and tested during the winter of 1980-1981. The power train included a five meter, three bladed wind turbine, a 9.8:1 ratio gearbox, a 1.44 cubic inch displacement pump with a small supercharge gear pump attached. The hydraulic fluid was pumped through a 70', 3/4'' I-D-high pressure flexhose, then through a volume control valve and into a 1.44 cubic inch displacement motor. The fluid was returned through a 70', 1'' I-D-flexhose.

  10. Speed, Acceleration, and Velocity: Level II, Unit 9, Lesson 1; Force, Mass, and Distance: Lesson 2; Types of Motion and Rest: Lesson 3; Electricity and Magnetism: Lesson 4; Electrical, Magnetic, and Gravitational Fields: Lesson 5; The Conservation and Conversion of Matter and Energy: Lesson 6; Simple Machines and Work: Lesson 7; Gas Laws: Lesson 8; Principles of Heat Engines: Lesson 9; Sound and Sound Waves: Lesson 10; Light Waves and Particles: Lesson 11; Program. A High.....

    ERIC Educational Resources Information Center

    Manpower Administration (DOL), Washington, DC. Job Corps.

    This self-study program for high-school level contains lessons on: Speed, Acceleration, and Velocity; Force, Mass, and Distance; Types of Motion and Rest; Electricity and Magnetism; Electrical, Magnetic, and Gravitational Fields; The Conservation and Conversion of Matter and Energy; Simple Machines and Work; Gas Laws; Principles of Heat Engines;…

  11. Energy Conversion: Nano Solar Cell

    NASA Astrophysics Data System (ADS)

    Yahaya, Muhammad; Yap, Chi Chin; Mat Salleh, Muhamad

    2009-09-01

    Problems of fossil-fuel-induced climate change have sparked a demand for sustainable energy supply for all sectors of economy. Most laboratories continue to search for new materials and new technique to generate clean energy at affordable cost. Nanotechnology can play a major role in solving the energy problem. The prospect for solar energy using Si-based technology is not encouraging. Si photovoltaics can produce electricity at 20-30 c//kWhr with about 25% efficiency. Nanoparticles have a strong capacity to absorb light and generate more electrons for current as discovered in the recent work of organic and dye-sensitized cell. Using cheap preparation technique such as screen-printing and self-assembly growth, organic cells shows a strong potential for commercialization. Thin Films research group at National University Malaysia has been actively involved in these areas, and in this seminar, we will present a review works on nanomaterials for solar cells and particularly on hybrid organic solar cell based on ZnO nanorod arrays. The organic layer consisting of poly[2-methoxy-5-(2-ethylhexyloxy)-1, 4-phenylenevinylene] (MEHPPV) and [6, 6]-phenyl C61-butyric acid 3-ethylthiophene ester (PCBE) was spin-coated on ZnO nanorod arrays. ZnO nanorod arrays were grown on FTO glass substrates which were pre-coated with ZnO nanoparticles using a low temperature chemical solution method. A gold electrode was used as the top contact. The device gave a short circuit current density of 2.49×10-4 mA/cm2 and an open circuit voltage of 0.45 V under illumination of a projector halogen light at 100 mW/cm2.

  12. A new, versatile Stirling energy conversion unit

    Microsoft Academic Search

    R. J. Meijer; B. Ziph

    1982-01-01

    A new concept in Stirling engine technology is embodied in the ''Base Engine'' now being developed at Stirling Thermal Motors, Inc. This is a versatile energy conversion unit suitable for many different applications and heat sources. The Base Engine, rated at 40 kw at 2800 rpm, is a four cylinder, double acting, variable displacement Stirling engine. It incorporates remote-heating technology

  13. Power conversion mechanisms for wave energy

    Microsoft Academic Search

    S H Salter; J R M Taylor; N J Caldwell

    2002-01-01

    It is easy to make a device that will respond vigorously to the action of sea waves. Indeed, it is quite hard to make one that will not. However, the conversion of the slow, random, reversing energy flows with very high extreme values into phase-locked synchronous electricity with power quality acceptable to a utility network is very much harder. This

  14. Open cycle ocean thermal energy conversion system

    Microsoft Academic Search

    Wittig; J. Michael

    1980-01-01

    An improved open cycle ocean thermal energy conversion system including a flash evaporator for vaporizing relatively warm ocean surface water and an axial flow, elastic fluid turbine having a vertical shaft and axis of rotation. The warm ocean water is transmitted to the evaporator through a first prestressed concrete skirt-conduit structure circumferentially situated about the axis of rotation. The unflashed

  15. Open cycle ocean thermal energy conversion system

    Microsoft Academic Search

    Wittig

    1980-01-01

    An improved open cycle ocean thermal energy conversion system includes a flash evaporator for vaporizing relatively warm ocean surface water and an axial flow, elastic fluid turbine having a vertical shaft and axis of rotation. The warm ocean water is transmitted to the evaporator through a first prestressed concrete skirt-conduit structure circumferentially situated about the axis of rotation. The unflashed

  16. Ocean thermal energy conversion hydro well apparatus

    Microsoft Academic Search

    1987-01-01

    An ocean thermal energy conversion apparatus is described comprising: (a) A vertical chamber extending downward into the ocean with its upper end near the surface of the ocean; (b) Air induction means suitable for introducing a stream of air bubbles into the sea water falling down the vertical chamber; (c) A generator means located at the lower end of the

  17. Radiant energy to electrical power conversion system

    Microsoft Academic Search

    Brunson

    1980-01-01

    A radiant energy to electrical power thermionic conversion system is disclosed that uses a transducer structure with very closely spaced cathode and anode elements in a vacuum to minimize space charge buildup and to optimize cross transfer of electrons from cathode to anode. The materials chosen are for a high work function high melt temperature cathode, tungsten for example with

  18. Germanium nanoparticles for solar energy conversion

    NASA Astrophysics Data System (ADS)

    Vörös, Márton; Wippermann, Stefan; Rocca, Dario; Galli, Giulia; Gali, Adam; Zimanyi, Gergely

    2013-03-01

    We propose a strategy to enhance the efficiency of solar energy conversion by elemental germanium, by using Multiple Exciton Generation (MEG) in Ge nanoparticles with a ST12 core structure. The latter is the structure of a high pressure phase of solid Ge. MEG is more efficient in bulk Ge in the diamond phase than in several other semiconductors, e.g. Si. In principle it may be further improved at the nanoscale, due to an increased effective Coulomb interaction. However the electronic energy gap of semiconducting nanoparticles may be too large compared to the visible solar spectrum and their density of states (DOS) too low for efficient solar energy conversion. Using ab initio calculations we found that ST12 Ge nanoparticles of ~1-2 nm exhibit high impact ionization rates and thus presumably efficient MEG, as well as a gap of ~2 eV and a sizable DOS in the low energy part of the spectrum. Therefore these nanoparticles appear to be promising materials for solar energy conversion exploiting MEG. We propose a strategy to enhance the efficiency of solar energy conversion by elemental germanium, by using Multiple Exciton Generation (MEG) in Ge nanoparticles with a ST12 core structure. The latter is the structure of a high pressure phase of solid Ge. MEG is more efficient in bulk Ge in the diamond phase than in several other semiconductors, e.g. Si. In principle it may be further improved at the nanoscale, due to an increased effective Coulomb interaction. However the electronic energy gap of semiconducting nanoparticles may be too large compared to the visible solar spectrum and their density of states (DOS) too low for efficient solar energy conversion. Using ab initio calculations we found that ST12 Ge nanoparticles of ~1-2 nm exhibit high impact ionization rates and thus presumably efficient MEG, as well as a gap of ~2 eV and a sizable DOS in the low energy part of the spectrum. Therefore these nanoparticles appear to be promising materials for solar energy conversion exploiting MEG. NSF Solar Collaborative DMR-1035468, NSF CHE-0802907

  19. Thermal Energy Conversion in Nanofluids

    NASA Astrophysics Data System (ADS)

    Taylor, Robert

    2011-12-01

    A relatively simple subset of nanotechnology---nanofluids---can be obtained by adding nanoparticles to conventional base fluids. The promise of these fluids stems from the fact that relatively low particle loadings (typically <1% volume fractions) can significantly change the properties of the base fluid. This research explores how low volume fraction nanofluids, composed of common base-fluids, interact with light energy. Comparative experimentation and modeling reveals that absorbing light volumetrically (i.e. in the depth of the fluid) is fundamentally different from surface-based absorption. Depending on the particle material, size, shape, and volume fraction, a fluid can be changed from being mostly transparent to sunlight (in the case of water, alcohols, oils, and glycols) to being a very efficient volumetric absorber of sunlight. This research also visualizes, under high levels of irradiation, how nanofluids undergo interesting, localized phase change phenomena. For this, images were taken of bubble formation and boiling in aqueous nanofluids heated by a hot wire and by a laser. Infrared thermography was also used to quantify this phenomenon. Overall, though, this research reveals the possibility for novel solar collectors in which the working fluid directly absorbs light energy and undergoes phase change in a single step. Modeling results indicate that these improvements can increase a solar thermal receiver's efficiency by up to 10%.

  20. Cluster observations of plasma sheet energy conversion near dipolarization fronts

    NASA Astrophysics Data System (ADS)

    Hamrin, M.; Norqvist, P.; Karlsson, T.; Nilsson, H.; Pitkänen, T.; Fu, H.; Marghitu, O.

    2013-12-01

    Bursty bulk flows (BBFs) play an important role for the mass, energy and magnetic flux transport in the plasma sheet. The flow pattern in and around a BBF is often rather complicated and it has important consequences for the localized energy conversion between the electromagnetic and plasma mechanical energy forms. A dipolarization front (DF) is often observed at the leading edge of a BBF, and a flux pileup region (FPR) behind the DFs. Return flows and plasma vortices are expected to exist at the the flanks of the main flow channel. Here we present Cluster measurements of the flow pattern and energy conversion near DFs observed in the plasma sheet. We discuss the energy conversion properties during various stages of the FPR evolution. By using a statistical data base of Cluster data we show that it is likely that an early stage FPR corresponds to a generator, consistent with the FPR build-up, while an FPR in its later stage corresponds to a load, as expected for the FPR decay.

  1. E2I EPRI Assessment Offshore Wave Energy Conversion Devices

    E-print Network

    E2I EPRI Assessment Offshore Wave Energy Conversion Devices Report: E2I EPRI WP ­ 004 ­ US ­ Rev 1 #12;E2I EPRI Assessment - Offshore Wave Energy Conversion Devices Table of Contents Introduction ............................................................................... 26 Appendix E - Orecon

  2. Thermoelectric energy conversion with solid electrolytes

    Microsoft Academic Search

    T. Cole

    1983-01-01

    The alkali metal thermoelectric converter (AMTEC) is a device for the direct conversion of heat to electrical energy. The sodium ion conductor beta-double prime-alumina is used to form a high-temperature regenerative concentration cell for elemental sodium. An AMTEC of mature design should have an efficiency of 20 to 40 percent, a power density of 0.5 kilowatt per kilogram or more,

  3. Thin film based thermoelectric energy conversion systems

    Microsoft Academic Search

    J. Nurnus; H. Bottner; C. Kunzel; U. Vetter; A. Lambrecht; J. Schumann; F. Volklein

    2002-01-01

    Up to now thermoelectric materials used in commercial energy conversion devices like infrared sensors, Peltier-coolers or thermogenerators do not take advantage of the enormous potentials provided by low-dimensional structures. The scope of this presentation is the experimental verification of the predicted increase of the thermoelectric figure of merit (FOM) ZT in low-dimensional systems above values of bulk materials. Concepts for

  4. Efficiency of Energy Conversion in Thermoelectric Nanojunctions

    Microsoft Academic Search

    Yu-Shen Liu; Yi-Ren Chen; Yu-Chang Chen

    2009-01-01

    Using first-principles approaches, this study investigated the efficiency of energy conversion in nanojunctions, described by the thermoelectric figure of merit $ZT$. We obtained the qualitative and quantitative descriptions for the dependence of $ZT$ on temperatures and lengths. A characteristic temperature: $T_{0}= \\\\sqrt{\\\\beta\\/\\\\gamma(l)}$ was observed. When $T\\\\ll T_{0}$, $ZT\\\\propto T^{2}$. When $T\\\\gg T_{0}$, $ZT$ tends to a saturation value. The dependence

  5. Solar thermochemical energy conversion and transport

    Microsoft Academic Search

    J. H. McCrary; G. E. McCrary

    1982-01-01

    The high temperature catalytic dissociation of SO3 and the CO2-CH4 reforming-methanation cycle are important chemical processes being considered in the development and application of solar-thermal energy conversion, transport, and storage systems. Separate facilities for evaluating chemical converter-heat exchangers at temperatures to 1000 C with high flow rates of SO3 and of mixtures of CO2 and CH4 feedstocks have been assembled

  6. Nanoengineered Materials for Thermoelectric Energy Conversion

    NASA Astrophysics Data System (ADS)

    Shakouri, Ali; Zebarjadi, Mona

    In this chapter we review recent advances in nanoengineered materials for thermoelectric energy conversion. We start by a brief overview of the fundamental interactions between heat and electricity, i.e., thermoelectric effects. A key requirement to improve the energy conversion efficiency is to increase the Seebeck coefficient (S) and the electrical conductivity (? ), while reducing the thermal conductivity (?). Nanostructures make it possible to modify the fundamental trade-offs between the bulk material properties through the changes in the density of states and interface effects on the electron and phonon transport. We will review recent experimental and theoretical results on superlattice and quantum dot thermoelectrics, nanowires, thin-film microrefrigerators, and solid-state thermionic power generation devices. In the latter case, the latest experimental results for semimetal rare-earth nanoparticles in a III-V semiconductor matrix as well as nitride metal/semiconductor multilayers will be discussed. We will briefly describe recent developments in nonlinear thermoelectrics, as well as electrically pumped optical refrigeration and graded thermoelectric materials. It is important to note that, while the material thermoelectric figure of merit (Z = S2? /? ) is a key parameter to optimize, one has to consider the whole system in an energy conversion application, and system optimization sometimes places other constraints on the materials.We will also review challenges in the experimental characterization of thin film thermoelectric materials. Finally, we will assess the potential of some of the more exotic techniques such as thermotunneling and bipolar thermoelectric effects.

  7. Thermal to electricity conversion using thermal magnetic properties

    DOEpatents

    West, Phillip B [Idaho Falls, ID; Svoboda, John [Idaho Falls, ID

    2010-04-27

    A system for the generation of Electricity from Thermal Energy using the thermal magnetic properties of a Ferromagnetic, Electrically Conductive Material (FECM) in one or more Magnetic Fields. A FECM is exposed to one or more Magnetic Fields. Thermal Energy is applied to a portion of the FECM heating the FECM above its Curie Point. The FECM, now partially paramagnetic, moves under the force of the one or more Magnetic Fields. The movement of the FECM induces an electrical current through the FECM, generating Electricity.

  8. Energy Conversion at Micro and Nanoscale

    NASA Astrophysics Data System (ADS)

    Gammaitoni, Luca

    2014-11-01

    Energy management is considered a task of strategic importance in contemporary society. It is a common fact that the most successful economies of the planet are the economies that can transform and use large quantities of energy. In this talk we will discuss the role of energy with specific attention to the processes that happens at micro and nanoscale. The description of energy conversion processes at these scales requires approaches that go way beyond the standard equilibrium termodynamics of macroscopic systems. In this talk we will address from a fundamental point of view the physics of the dissipation of energy and will focus our attention to the energy transformation processes that take place in the modern micro and nano information and communication devices.

  9. Energy Conversion and Storage Program. 1990 annual report

    Microsoft Academic Search

    Cairns

    1992-01-01

    The Energy Conversion and Storage Program applies chemistry and materials science principles to solve problems in (1) production of new synthetic fuels, (2) development of high-performance rechargeable batteries and fuel cells, (3) development of advanced thermochemical processes for energy conversion, (4) characterization of complex chemical processes, and (5) application of novel materials for energy conversion and transmission. Projects focus on

  10. IEEE Transactions on Energy Conversion, Vol. 14, No. 4, December 1999 1043 OptimalCurrent Control Strategies for Surface-MountedPermanent-Magnet

    E-print Network

    Chapman, Patrick

    Strategies for Surface-MountedPermanent-Magnet SynchronousMachine Drives P.L. Chapman,Member S minimizing the rms stator Permanent-magnet synchronous machine (PMSM) drives current was set forth in [6 the mathematical analysis is quite different. These rotor losses and the absence of magnetizing CUrrent

  11. Innovative oxide materials for electrochemical energy conversion

    NASA Astrophysics Data System (ADS)

    Wachsman, Eric D.

    2012-02-01

    Research in functional materials has progressed from those materials exhibiting structural to electronic functionality. The study of ion conducting ceramics ushers in a new era of ``chemically functional materials.'' This chemical functionality arises out of the defect equilibria of these materials, and results in the ability to transport chemical species and actively participate in chemical reactions at their surface. Moreover, this chemical functionality provides a promise for the future whereby the harnessing of our natural hydrocarbon energy resources can shift from inefficient and polluting combustion - mechanical methods to direct electrochemical conversion. The unique properties of these materials and their applications will be described. The focus will be on the application of ion conducting ceramics to energy conversion and storage, chemical sensors, chemical separation and conversion, and life support systems. Results presented will include development of record high power density (3 kW/kg) solid oxide fuel cells, NOx/CO species selective solid-state sensors, high yield membrane reactors, and regenerative life support systems that reduce CO2 to O2 and solid C.

  12. River Inflow Characteristics for Hydrokinetic Energy Conversion

    NASA Astrophysics Data System (ADS)

    Neary, V. S.; Sale, D.; Gunawan, B.

    2011-12-01

    Most of our knowledge on current energy conversion resource characterization is derived from the wind power industry. River current resource characterization for hydrokinetic technologies can certainly borrow from this knowledge base, but must consider unique attributes associated with river hydrodynamics. Published turbulent flow data from large rivers, a canal and laboratory flumes are reviewed to determine the range of velocities and longitudinal turbulence intensities acting on hydrokinetic technologies, and also to evaluate the validity of classical models that describe the depth variation of the time-mean velocity and turbulent Reynolds stresses. A key challenge in river flow characterization is the high variability of depth and flow over the design life of a hydrokinetic device. This variation will have significant effects on the inflow mean velocity and turbulence intensity experienced by the hydrokinetic device, which requires further investigation. These effects may significantly alter estimates of energy production, structural loads, and ultimately the cost of energy at a river resource site.

  13. Plasmon-graviton conversion in a magnetic field in TeV-scale gravity

    E-print Network

    E. Yu. Melkumova

    2011-12-13

    Kaluza-Klein (KK) gravitons emission rates due to plasmon-graviton conversion in magnetic field are computed within the ADD model of TeV-scale gravity. Plasma is described in the kinetic approach as the system of charged particles and Maxwell field both confined on the brane. Interaction with multidimensional gravity living in the bulk with $n$ compact extra dimensions is introduced within the linearized theory. Plasma collective effects enter through the two-point correlation function of the fluctuations of the energy-momentum tensor. The estimate for magnetic stars is presented leading to the lower limit of the D-dimensional Plank mass.

  14. Device for the conversion of solar energy into electrical energy

    Microsoft Academic Search

    Bellugue

    1981-01-01

    A device is described for the conversion of solar energy into electrical energy with the aid of a photovoltaic cell. A central lens forms a round radiation spot on the radiation-sensitive area of the cell, while a toric mirror arranged round the lens forms an annular radiation spot. Thus, it is ensured that the entire area of the cell remains

  15. Conversion of laser energy to gas kinetic energy

    Microsoft Academic Search

    G. E. Caledonia

    1975-01-01

    Techniques for the gas phase absorption of laser radiation for conversion to gas kinetic energy are discussed. Absorption by inverse Bremsstrahlung, in which laser energy is converted at a gas kinetic rate in a spectrally continuous process, is briefly described, and absorption by molecular vibrational rotation bands is discussed at length. High pressure absorption is proposed as a means of

  16. Mode Conversion of Solar p-Modes In Non-Vertical Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Crouch, A. D.; Cally, P. S.

    2004-01-01

    Sunspots absorb and scatter incident - and -modes. One suggested absorption mechanism is mode conversion to slow magnetoacoustic-gravity waves, which carry some of the energy down magnetic field lines into the interior, or, less preferentially, up into the overlying atmosphere. Assuming uniform vertical magnetic field, this mechanism easily explains -mode absorption, but cannot fully account for the observed absorption of -modes, especially beyond the first few radial orders. Recently, we have calculated the efficiency of mode conversion in uniform non-vertical magnetic fields assuming two dimensional propagation, where the Alfvén waves decouple. In moderately inclined field ( ) at higher frequencies ( ), we found significant absorption enhancements - up to an order of magnitude. Using these two dimensional calculations, Cally, Crouch, and Braun constructed a simplified model for the interaction between a sunspot and its surroundings. They found excellent agreement with the observational -mode absorption and phase shift data. In this investigation, we determine the efficiency of mode conversion in non-vertical magnetic field with three dimensional propagation, where fast and slow magnetoacoustic-gravity waves and Alfvén waves are all coupled.

  17. Parametric energy conversion of thermoacoustic vibrations

    NASA Astrophysics Data System (ADS)

    Guthy, C.; Van Neste, C. W.; Mitra, S.; Bhattacharjee, S.; Thundat, T.

    2012-05-01

    We demonstrate a parametric energy conversion method of thermoacoustic (TA) vibrations into electrical oscillations of a LC circuit. The inductance modulation necessary to excite the parametric oscillations is achieved by varying the air gap between two halves of a ferrite E-core coil. As a proof-of-concept, the parametric converter was attached to a Sondhauss tube that converts the heat into acoustic vibrations. The maximum total acoustic power output of this thermoacoustic engine was ˜5.3 mW. A flexible metallic membrane capping the Sondhauss tube connected to the moving half E-core served as a mechanical oscillator. The resonance frequency of the membrane was matched with the operating frequency (130 Hz) of the Sondhauss tube for resonant energy extraction. We have characterized the power output of the complete system as a function of electrical load. The maximum electrical power of 2.3 mW produced by the system corresponds to an acoustic-to-electric conversion efficiency of 44%.

  18. Energy transfer processes in solar energy conversion

    SciTech Connect

    Fayer, M.D.

    1986-11-01

    By combining picosecond optical experiments and detailed statistical mechanics theory we continue to increase our understanding of the complex interplay of structure and dynamics in important energy transfer situations. A number of different types of problems will be focused on experimentally and theoretically. They are excitation transport among chromophores attached to finite size polymer coils; excitation transport among chromophores in monolayers, bilayers, and finite and infinite stacks of layers; excitation transport in large vesicle systems; and photoinduced electron transfer in glasses and liquids, focusing particularly on the back transfer of the electron from the photogenerated radical anion to the radical cation. 33 refs., 13 figs.

  19. Stochastic conversions of TeV photons into axion-like particles in extragalactic magnetic fields

    NASA Astrophysics Data System (ADS)

    Mirizzi, Alessandro; Montanino, Daniele

    2009-12-01

    Very-high energy photons emitted by distant cosmic sources are absorbed on the extragalactic background light (EBL) during their propagation. This effect can be characterized in terms of a photon transfer function at Earth. The presence of extragalactic magnetic fields could also induce conversions between very high-energy photons and hypothetical axion-like particles (ALPs). The turbulent structure of the extragalactic magnetic fields would produce a stochastic behaviour in these conversions, leading to a statistical distribution of the photon transfer functions for the different realizations of the random magnetic fields. To characterize this effect, we derive new equations to calculate the mean and the variance of this distribution. We find that, in presence of ALP conversions, the photon transfer functions on different lines of sight could have relevant deviations with respect to the mean value, producing both an enhancement or a suppression in the observable photon flux with respect to the expectations with only absorption. As a consequence, the most striking signature of the mixing with ALPs would be a reconstructed EBL density from TeV photon observations which appears to vary over different directions of the sky: consistent with standard expectations in some regions, but inconsistent in others.

  20. Silicides: Materials for thermoelectric energy conversion

    NASA Astrophysics Data System (ADS)

    Fedorov, Mikhail I.; Isachenko, Grigory N.

    2015-07-01

    There are few silicides that could be used for thermoelectric energy conversion, following higher silicides of transition metals: CrSi2, MnSi1.75, ?-FeSi2, Ru2Si3, ReSi1.75, and solid solutions based on compounds of Mg2X (X = Si, Ge, and Sn). Some of them have very high figures of merit (ZT). It can be shown that, in some silicides, a high ZT is the result of energy spectrum optimization besides the decrease in thermal conductivity. This is very difficult to achieve in some materials, because the density of states is typically dependent only on the band structure of a material, for which there is no means to produce such a change. However, in solid solutions, if they have a special band structure of components, it is possible to alter the band structure to increase ZT.

  1. Recycling of Wasted Energy: Thermal to Electrical Energy Conversion

    NASA Astrophysics Data System (ADS)

    Lim, Hyuck

    Harvesting useful electric energy from ambient thermal gradients and/or temperature fluctuations is immensely important. For many years, a number of direct and indirect thermal-to-electrical energy conversion technologies have been developed. Typically, direct energy conversion is achieved by using thermoelectric generators or thermogalvanic cells; indirect energy conversion is achieved by using Organic Rankine Cycle or Sterling Engines. On the one hand, there is a fundamental technical difficulty, thermal shorting, that limits the energy conversion efficiency of direct thermoelectric energy conversion methods. While extensive study has been conducted in this area, currently the portion of thermal energy that can be converted to electricity is still small. On the other hand, the indirect energy conversion systems tend to be complicated and expensive. Thus, existing energy harvesting technologies are less economically competitive compared with the grid power. To develop advanced energy harvesting systems, a novel concept using nanoporous materials is investigated. Nanoporous materials have been widely used as advanced absorbents. Because of their ultra-large surface areas (100--2000 m2/g), they can adsorb a large amount of ions when they are immersed in electrolyte solutions. The ion adsorption capacity is thermally dependent. If two nanoporous electrodes are placed at different temperatures, they adsorb different amounts of ions, generating a net output voltage. The thermally driven ion motion causes a transient current, which can be reactivated through temperature fluctuation or internal grounding. The two electrodes are isolated; that is, the direct heat loss between them is minimized. Our experimental data have shown encouraging results: the output voltage and the energy conversion efficiency are higher than that of conventional thermoelectric materials by orders of magnitude. Our study will not only lead to the development of high-performance thermal energy harvesting systems, but also shed light on fundamentals of electrophysics in nanoenvironment. The thermal effect on surface electrification (i.e. the capacitive effect) in nanopores is a new scientific area. Conventional interface theories have failed in explaining a number of experimental observations. We have carried out a systematic study of the effects of ions, solvent, electrode, cell configuration, etc. to understand the fundamental mechanisms and processes that govern the ion motion and charge transfer in nanopores.

  2. Proceedings of the 33. intersociety energy conversion engineering conference

    Microsoft Academic Search

    Anghaie

    1998-01-01

    These papers were presented at the Intersociety Energy Conversion Engineering Conference, August of 1998. The topics of the papers included aerospace power analyses and simulation, space energy conversion, applications and requirements for space power systems, space solar power, terrestrial energy, aerospace batteries, aerospace power management, aerospace power electronics, aircraft power, dual use technologies, electric propulsion, wireless energy transmission, terrestrial thermoelectric,

  3. Semiconductor Nanowires for Energy Conversion Allon I. Hochbaum*,

    E-print Network

    Wu, Zhigang

    of Materials in Energy Conversion Between 2004 and 2030 the annual global consumption of energy is estimated power consumption in- creases, there will be an increasing need for new energy storage schemes. PushingSemiconductor Nanowires for Energy Conversion Allon I. Hochbaum*, and Peidong Yang* Department

  4. Flux and conversion of solar-wind energy in the transition region of the magnetosphere

    Microsoft Academic Search

    M. I. Pudovkin; V. S. Semenov

    1986-01-01

    The flux transferred from the solar wind to the earth magnetosphere is calculated. It is shown that the Poynting-vector flux transferred to the reconnection region is primarily generated in the transition region between the detached-shock front and the magnetopause because of the deceleration of the solar wind and the partial conversion of its kinetic energy into magnetic energy. The dependence

  5. Axial inlet conversion to a centrifugal compressor with magnetic bearings

    SciTech Connect

    Novecosky, T. (NOVA Corp., Edmonton, Alberta (Canada))

    1994-01-01

    NOVA's Alberta Gas Transmission Division transports natural gas via pipeline throughout the province of Alberta, Canada, exporting it to eastern Canada, US, and British Columbia. There is a continuing effort to operate the facilities and pipeline at the highest possible efficiency. One area being addressed to improve efficiency is compression of the gas. By improving compressor efficiency, fuel consumption and hence operating costs can be reduced. One method of improving compressor efficiency is by converting the compressor to an axial inlet configuration, a conversion that has been carried out more frequently in the past years. Concurrently, conventional hydrodynamic bearings have been replaced with magnetic bearings on many centrifugal compressors. This paper discusses the design and installation for converting a radial overhung unit to an axial inlet configuration, having both magnetic bearings and a thrust reducer. The thrust reducer is required to reduce axial compressor shaft loads, to a level that allows the practical installation of magnetic bearings within the space limitations of the compressor (Bear and Gibson, 1992).

  6. A new, versatile Stirling energy conversion unit

    SciTech Connect

    Meijer, R.J.; Ziph, B.

    1982-08-01

    A new concept in Stirling engine technology is embodied in the ''Base Engine'' now being developed at Stirling Thermal Motors, Inc. This is a versatile energy conversion unit suitable for many different applications and heat sources. The Base Engine, rated at 40 kw at 2800 rpm, is a four cylinder, double acting, variable displacement Stirling engine. It incorporates remote-heating technology with a stacked-heat-exchanger configuration and a liquid metal heat pipe connected to a distinctly separate combustor or other heat source. It specifically emphasizes high efficiency over a wide range of operating conditions, long life, low manufacturing cost and low material cost. This paper describes the Base Engine, its design philosophy and approach, its projected performance, and some of its more attractive applications.

  7. Modeling and analysis of energy conversion systems

    SciTech Connect

    Den Braven, K.R. (Idaho Univ., Moscow, ID (USA). Dept. of Mechanical Engineering); Stanger, S. (EG and G Idaho, Inc., Idaho Falls, ID (USA))

    1990-10-01

    An investigation was conducted to assess the need for and the feasibility of developing a computer code that could model thermodynamic systems and predict the performance of energy conversion systems. To assess the market need for this code, representatives of a few industrial organizations were contacted, including manufacturers, system and component designers, and research personnel. Researchers and small manufacturers, designers, and installers were very interested in the possibility of using the proposed code. However, large companies were satisfied with the existing codes that they have developed for their own use. Also, a survey was conduced of available codes that could be used or possibly modified for the desired purpose. The codes were evaluated with respect to a list of desirable features, which was prepared as a result of the survey. A few publicly available codes were found that might be suitable. The development, verification, and maintenance of such a code would require a substantial, ongoing effort. 21 refs.

  8. Thermoelectric energy conversion with solid electrolytes

    NASA Astrophysics Data System (ADS)

    Cole, T.

    1983-09-01

    The alkali metal thermoelectric converter (AMTEC) is a device for the direct conversion of heat to electrical energy. The sodium ion conductor beta-double prime-alumina is used to form a high-temperature regenerative concentration cell for elemental sodium. An AMTEC of mature design should have an efficiency of 20 to 40 percent, a power density of 0.5 kilowatt per kilogram or more, no moving parts, low maintenance requirements, high durability, and efficiency independent of size. It should be usable with high-temperature combustion, nuclear, or solar heat sources. Experiments have demonstrated the feasibility of the AMTEC and confirmed the theoretical analysis of the device. A wide range of applications from aerospace power to utility power plants appears possible.

  9. Thermoelectric energy conversion with solid electrolytes.

    PubMed

    Cole, T

    1983-09-01

    The alkali metal thermoelectric converter (AMTEC) is a device for the direct conversion of heat to electrical energy. The sodium ion conductor beta"- alumina is used to form a high-temperature regenerative concentration cell for elemental sodium. An AMTEC of mature design should have an efficiency of 20 to 40 percent, a power density of 0.5 kilowatt per kilogram or more, no moving parts, low maintenance requirements, high durability, and efficiency independent of size. It should be usable with high-temperature combustion, nuclear, or solar heat sources. Experiments have demonstrated the feasibility of the AMTEC and confirmed the theoretical analysis of the device. A wide range of applications from aerospace power to utility power plants appears possible. PMID:17748444

  10. Thermoelectric energy conversion with solid electrolytes

    SciTech Connect

    Cole, T.

    1983-09-02

    The alkali metal thermoelectric converter (AMTEC) is a device for the direct conversion of heat to electrical energy. The sodium ion conductor beta''-alumina is used to form a high-temperature regenerative concentration cell for elemental sodium. An AMTEC of mature design should have an efficiency of 20 to 40%, a power density of 0.5 kilowatt per kilogram or more, no moving parts, low maintenance requirements, high durability, and efficiency independent of size. It should be usable with high-temperature combustion, nuclear, or solar heat sources. Experiments have demonstrated the feasibility of the AMTEC and confirmed the theoretical analysis of the device. A wide range of applications from aerospace power to utility power plants appears possible.

  11. Thermoelectric energy conversion with solid electrolytes

    NASA Technical Reports Server (NTRS)

    Cole, T.

    1983-01-01

    The alkali metal thermoelectric converter (AMTEC) is a device for the direct conversion of heat to electrical energy. The sodium ion conductor beta-double prime-alumina is used to form a high-temperature regenerative concentration cell for elemental sodium. An AMTEC of mature design should have an efficiency of 20 to 40 percent, a power density of 0.5 kilowatt per kilogram or more, no moving parts, low maintenance requirements, high durability, and efficiency independent of size. It should be usable with high-temperature combustion, nuclear, or solar heat sources. Experiments have demonstrated the feasibility of the AMTEC and confirmed the theoretical analysis of the device. A wide range of applications from aerospace power to utility power plants appears possible.

  12. Stretchable energy storage and conversion devices.

    PubMed

    Yan, Chaoyi; Lee, Pooi See

    2014-09-10

    Stretchable electronics are a type of mechanically robust electronics which can be bended, folded, crumpled and stretched and represent the emerging direction towards next-generation wearable and implantable devices. Unlike existing electronics based on rigid Si technologies, stretchable devices can conform to the complex non-coplanar surfaces and provide unique functionalities which are unreachable with simple extension of conventional technologies. Stretchable energy storage and conversion devices are the key components for the fabrication of complete and independent stretchable systems. In this review, we present the recent progresses in the developments of stretchable power sources including supercapacitors, batteries and solar cells. Representative structural and material designs to impart stretchability to the originally rigid devices are discussed. Advantages and drawbacks associated with the fabrication methods are also analysed. Summaries of the research progresses along with future development directions for this exciting field are also presented. PMID:25340184

  13. Energy conversion for megawatt space power systems

    SciTech Connect

    Ewell, R.

    1983-08-01

    Large nuclear space power systems capable of continuously producing over one megawatt of electrical power for a several year period will be needed in the future. This paper presents the results of a study to compare applicable conversion technologies which were deemed to be ready for a time period of 1995 and beyond. A total of six different conversion technologies were studied in detail and compared on the basis of conversion efficiency, radiator area, overall system mass, and feasibility. Three static, modular conversion technologies were considered; these include: AMTEC, thermionic, and thermoelectric conversion. The other three conversion technologies are heat engines which involve dynamic components. The dynamic systems analyzed were Brayton, Rankine, and the free piston Stirling engine. Each of the conversion techniques was also examined for limiting characteristics and an attempt was made to identify common research needs and enabling technologies.

  14. New highly polar semiconductor ferroelectrics for solar energy conversion devices

    Microsoft Academic Search

    Andrew M. Rappe; Ilya Grinberg; Joseph W. Bennett

    2009-01-01

    Solar energy is a promising long-term solution for future energy requirements; however, current solar energy conversion devices are plagued by low efficiency. The use of ferroelectric ABO3 perovskite oxides is one approach for boosting conversion efficiency. Ferroelectric oxides possess spontaneous polarization and have been shown to produce a bulk photovoltaic effect, in which charged carriers, specifically electrons and holes, separate

  15. Antimatter-initiated microfusion: Direct energy conversion for propulsion applications

    NASA Astrophysics Data System (ADS)

    Kramer, Kevin J.; Smith, Gerald A.

    2002-01-01

    An analysis has been performed on major components of a direct energy conversion system DIPEC (Direct Propellant Ionization Energy Conversion) for AIMStar (Antimatter-Initiated Microfusion Starship) propulsion applications to deep space. Results for distributed energies, efficiencies, thrust and 1sp are presented. .

  16. Energy Conversion and Storage Program: 1992 Annual report

    Microsoft Academic Search

    Cairns

    1993-01-01

    This report is the 1992 annual progress report for the Energy Conversion and Storage Program, a part of the Energy and Environment Division of the Lawrence Berkeley Laboratory. Work described falls into three broad areas: electrochemistry; chemical applications; and materials applications. The Energy Conversion and Storage Program applies principles of chemistry and materials science to solve problems in several areas:

  17. Direct-Write Piezoelectric Polymeric Nanogenerator with High Energy Conversion

    E-print Network

    Lin, Liwei

    Nanogenerator, near-field electrospinning, direct-write nanofibers, piezoelectric, energy harvestingDirect-Write Piezoelectric Polymeric Nanogenerator with High Energy Conversion Efficiency Chieh for many applications, including energy harvesters. In this work, near-field electrospinning is used

  18. Thermoelectrics and aerogels for solar energy conversion systems

    E-print Network

    McEnaney, Kenneth

    2015-01-01

    Concerns about climate change, the world's growing energy needs, and energy independence are driving demand for solar energy conversion technologies. Solar thermal electricity generation has the potential to ll this demand. ...

  19. Direct energy conversion using liquid metals

    NASA Astrophysics Data System (ADS)

    Onea, Alexandru; Diez de los Rios Ramos, Nerea; Hering, Wolfgang; Stieglitz, Robert; Moster, Peter

    2014-12-01

    Liquid metals have excellent properties to be used as heat transport fluids due to their high thermal conductivity and their wide applicable temperature range. The latter issue can be used to go beyond limitations of existing thermal solar energy systems. Furthermore, the direct energy converter Alkali Metal Thermo Electric Converter (AMTEC) can be used to make intangible areas of energy conversion suitable for a wide range of applications. One objective is to investigate AMTEC as a complementary cycle for the next generation of concentrating solar power (CSP) systems. The experimental research taking place in the Karlsruhe Institute of Technology (KIT) is focused on the construction of a flexible AMTEC test facility, development, test and improvement of liquid-anode and vapor-anode AMTEC devices as well as the coupling of the AMTEC cold side to the heat storage tank proposed for the CSP system. Within this project, the investigations foreseen will focus on the analyses of BASE-metal interface, electrode materials and deposition techniques, corrosion and erosion of materials brought in contact with high temperature sodium. This prototype demonstrator is planned to be integrated in the KArlsruhe SOdium LAboratory (KASOLA), a flexible closed mid-size sodium loop, completely in-house designed, presently under construction at the Institute for Neutron Physics and Reactor Technology (INR) within KIT.

  20. Energy Conversion Alternatives Study (ECAS), General Electric Phase 1. Volume 3: Energy conversion subsystems and components. Part 1: Bottoming cycles and materials of construction

    NASA Technical Reports Server (NTRS)

    Shah, R. P.; Solomon, H. D.

    1976-01-01

    Energy conversion subsystems and components were evaluated in terms of advanced energy conversion systems. Results of the bottoming cycles and materials of construction studies are presented and discussed.

  1. Progress on PEP-II Magnet Power Conversion System?

    SciTech Connect

    Bellomo, P.; Genova, L.; Jackson, T.; Shimer, D.

    1996-06-01

    The various power systems for supplying the PEP-II DCmagnets rely exclusively on switch mode conversion, utilizing a varietyof means depending on the requirements. All of the larger power supplies,ranging from 10 to 200 kW, are powered from DC sources utilizingrectified 480 V AC. Choppers can be used for the series connectedstrings, but for smaller groups and individual magnets, inverters drivinghigh-frequency transformers with secondary rectifiers comprise the bestapproach. All of the various systems use a "building block" approach ofmultiple standard-size units connected in series or parallel to mostcost-effectively deal with a great range of voltage and currentrequirements. Utilization of existing infrastructure from PEP-I has beena cost-effective determinant. Equipment is being purchased eitheroff-the-shelf, through performance specification, or by hardware purchasebased on design-through-prototype. The corrector magnet power system,utilizing inexpensive, off-the-shelf four-quadrant switching motorcontrollers, has already proven very reliable: 120 of the total of 900units have been running on the injection system for four months with nofailures.

  2. Nanomaterials for energy conversion and storage.

    PubMed

    Zhang, Qifeng; Uchaker, Evan; Candelaria, Stephanie L; Cao, Guozhong

    2013-04-01

    Nanostructured materials are advantageous in offering huge surface to volume ratios, favorable transport properties, altered physical properties, and confinement effects resulting from the nanoscale dimensions, and have been extensively studied for energy-related applications such as solar cells, catalysts, thermoelectrics, lithium ion batteries, supercapacitors, and hydrogen storage systems. This review focuses on a few select aspects regarding these topics, demonstrating that nanostructured materials benefit these applications by (1) providing a large surface area to boost the electrochemical reaction or molecular adsorption occurring at the solid-liquid or solid-gas interface, (2) generating optical effects to improve optical absorption in solar cells, and (3) giving rise to high crystallinity and/or porous structure to facilitate the electron or ion transport and electrolyte diffusion, so as to ensure the electrochemical process occurs with high efficiency. It is emphasized that, to further enhance the capability of nanostructured materials for energy conversion and storage, new mechanisms and structures are anticipated. In addition to highlighting the obvious advantages of nanostructured materials, the limitations and challenges of nanostructured materials while being used for solar cells, lithium ion batteries, supercapacitors, and hydrogen storage systems have also been addressed in this review. PMID:23455759

  3. PEP-III magnet power conversion systems: Power supplies for large magnet strings

    SciTech Connect

    Jackson, T. [Lawrence Berkeley Lab., CA (United States); Saab, A. [Stanford Linear Accelerator Center, Menlo Park, CA (United States); Shimer, D. [Lawrence Livermore National Lab., CA (United States)

    1995-05-01

    This paper presents the cooperative design efforts of LBL, SLAC, and LLNL on the magnet power conversion systems for PEP-II. The systems include 900 channels of correction magnet bipolar supplies and 400 unipolar supplies in the range of 5 to 500 kW. We show the decision process and technical considerations influencing the choice of power supply technologies employed. We also show the development of specifications that take maximum advantage of both the resources available and existing facilities while at the same time satisfying tight constraints for cost control, scheduling and coordination of different working groups. Switch-mode power conversion techniques will be used extensively in these systems, from the corrector supplies to the largest units if the dynamic performance specifications demand it. General system descriptions for each of the power supply ranges and for a new common control system interface and regulator are included.

  4. Wind Energy Conversion Using A Self-Excited Induction Generator

    Microsoft Academic Search

    G. Raina; O. P. Malik

    1983-01-01

    A wind energy conversion scheme using an induction machine driven by a variable speed wind turbine is described. Excitation control has been obtained by employing a single value capacitor and thyristor controlled inductor. Wind speed cube law is proposed to be followed in loading the induction machine for maximising energy conversion. Performance characteristics of the generation scheme have been evaluated

  5. Thermal noise can facilitate energy conversion by a ratchet system.

    PubMed

    Takagi, F; Hondou, T

    1999-10-01

    Molecular motors in biological systems are expected to use ambient fluctuation. In a recent paper [Phys. Rev. Lett. 80, 5251 (1998)], it was shown that the following question was unanswered: Can thermal noise facilitate energy conversion by ratchet system? We consider it using stochastic energetics, and show that there exist systems where thermal noise helps the energy conversion. PMID:11970363

  6. Science of Nanofluidics and Energy Conversion

    NASA Astrophysics Data System (ADS)

    Xu, Baoxing

    The emerging subject of nanofluidics, where solids and fluids interact closely at the nanoscale, has exhibited radically different from their macroscopic counterparts (and sometimes counterintuitive), and yet relatively less explored. On the other hand, the resulting unique properties may contribute to a number of innovative functions with fascinating applications. Among various exciting potential applications, an important and ever expanding one is to provide alternative solutions to energy conversion with high efficiency, including energy absorption, actuation and harvesting. In this dissertation, we first report a novel protection mechanism of energy capture through which an intensive impact or blast energy can be effectively mitigated based on a nonwetting liquid-nanoporous material system. The captured energy is stored in nanopores in the form of potential energy of intercalated water molecules for a while, and not necessarily converted to other forms of energy (e.g. heat). At unloading stage, the captured energy will be released gradually due to the hydrophobic inner surfaces of nanopores through the diffusion of water molecules out of nanopores, thus making this system reusable. Several key controlling factors including impacting velocity, nanopore size, nanopore structure, and liquid phase have been investigated on the capacity of energy capture. The molecular mechanism is elucidated through the study of water molecular distributions inside nanpores. These molecular dynamic (MD) findings are quantitatively verified by a parallel blast experiment on a zeolite/water system. During the transport of confined liquid molecules, the friction resistance exerted by solid atoms of nanopores to liquid molecules will dissipate part of energy, and is highly dependent of temperature of liquid molecules and wall morphology of nanopores. Using MD simulations, the effects of temperature and wall roughness on the transport resistance of water molecules inside nanopores are investigated in Chapter 3. The effective shear stress and nominal viscosity that dominate the nanofluidic transport resistance are extracted and coupled with the nanopore size, transport rate, and liquid property. The molecular-level mechanisms are revealed through the study of the density profile and hydrogen bonding of confined liquid molecules. A parallel experiment on a nanoporous carbon-liquid system is carried out and qualitatively verifies MD findings. Motived by the well-known thermo- and electro-capillary effect, Chapter 4 and Chapter 5 present a conceptual design of thermal and electric actuation system by adjusting the relative hydrophobicity of a liquid-nanoporous system through a thermal and electric field, respectively. The thermally and electrically dependent infiltration behaviors of liquids into nanopores are analyzed by using MD simulations. The fundamental molecular characteristics, including the density profile, contact angle, and surface tension of the confined liquid molecules, are examined to reveal underlying mechanisms. The energy density, power density, and efficiency of both thermal and electric actuation systems are explored and their variations with pore size, solid phase, and liquid phase are evaluated. Thermally and electrically controlled infiltration experiments on a zeolite-water /electrolyte solution system are performed accordingly to qualitatively validate these findings. These energy actuation systems can also become high density thermal or electric storage devices with proper designs. Energy harvesting by the flow of a hydrochloric acid-water solution through a nanopore is explored using atomistic simulations in the last chapter. Through ion configurations near the pore wall, an averaged ion drifting velocity is determined, and the induced voltage along the axial direction is obtained as a function of key material parameters, including the applied flow rate, environmental temperature, solution concentration and nanopore size. The molecular mechanism of ion hopping and motion is revealed. This study shed light on harvesting

  7. Fundamental formulae for wave-energy conversion

    PubMed Central

    Falnes, Johannes; Kurniawan, Adi

    2015-01-01

    The time-average wave power that is absorbed from an incident wave by means of a wave-energy conversion (WEC) unit, or by an array of WEC units—i.e. oscillating immersed bodies and/or oscillating water columns (OWCs)—may be mathematically expressed in terms of the WEC units' complex oscillation amplitudes, or in terms of the generated outgoing (diffracted plus radiated) waves, or alternatively, in terms of the radiated waves alone. Following recent controversy, the corresponding three optional expressions are derived, compared and discussed in this paper. They all provide the correct time-average absorbed power. However, only the first-mentioned expression is applicable to quantify the instantaneous absorbed wave power and the associated reactive power. In this connection, new formulae are derived that relate the ‘added-mass’ matrix, as well as a couple of additional reactive radiation-parameter matrices, to the difference between kinetic energy and potential energy in the water surrounding the immersed oscillating WEC array. Further, a complex collective oscillation amplitude is introduced, which makes it possible to derive, by a very simple algebraic method, various simple expressions for the maximum time-average wave power that may be absorbed by the WEC array. The real-valued time-average absorbed power is illustrated as an axisymmetric paraboloid defined on the complex collective-amplitude plane. This is a simple illustration of the so-called ‘fundamental theorem for wave power’. Finally, the paper also presents a new derivation that extends a recently published result on the direction-average maximum absorbed wave power to cases where the WEC array's radiation damping matrix may be singular and where the WEC array may contain OWCs in addition to oscillating bodies.

  8. Solar energy conversion using surface plasmons for broadband energy transport

    NASA Technical Reports Server (NTRS)

    Anderson, L. M.

    1982-01-01

    A new strategy for efficient solar energy conversion based on parallel processing with surface plasmons is introduced. The approach is unique in identifying: (1) a broadband carrier with suitable range for energy transport, and (2) a technique to extract more energy from the more energetic photons, without sequential losses or unique materials for each frequency band. The aim is to overcome the fundamental losses associated with the broad solar spectrum and to achieve a higher level of spectrum splitting than has been possible in semiconductor systems.

  9. 26th Intersociety Energy Conversion Engineering Conference

    SciTech Connect

    Dudenhoefer, J.E.; Winter, J.M.

    1991-01-01

    An overview is presented of the NASA-Lewis Free-Piston Stirling Space Power Convertor Technology Program. The goal is to develop the technology base needed to meet the long duration, high capacity power requirements for future NASA space initiatives. Efforts are focused upon increasing system power output and system thermal and electric energy conversion efficiency at least fivefold over current SP-100 technology, and on achieving systems that are compatible with space nuclear reactors. Stirling experience in space and progress toward 1050 and 1300 K Stirling Space Power Converters is discussed. Fabrication is nearly completed for the 1050 K Component Test Power Converters (CTPC); results of motoring tests of cold end (525 K), are presented. The success of these and future designs is dependent upon supporting research and technology efforts including heat pipes, bearings, superalloy joining technologies, high efficiency alternators, life and reliability testing and predictive methodologies. An update is provided of progress in some of these technologies leading off with a discussion of free-piston Stirling experience in space.

  10. Performance of Tornado Wind Energy Conversion Systems

    SciTech Connect

    Volk, T.

    1982-09-01

    The flow characteristics and power production capabilities of the Tornado Wind Energy Conversion System (TWECS) are examined. Experimental results indicate that the confined vortex in the tower of TWECS rotates approximately as a solid body and only supplements total power production, most of which comes from the tower acting as a bluff body. Wrapped tower experiments were performed by fitting a plastic shroud 360 deg around the tower from the top of the bottom inlet to the tower exit level which transformed the TWECS into a hollow, raised cylinder. Coefficient of power is compared for louvered towers vs. wrapped tower. The fact that the wrapped tower performs as well as the louvered tower suggests that it is the pressure difference between the bottom inlet region and the region above the tower (where the pressure of the ambient flow will be somewhat reduced owing to its acceleration over the bluff body of the tower) which determines the vertical force on the fluid within the tower.

  11. Energy of Alfven waves generated during magnetic reconnection

    E-print Network

    Wang, L C; Ma, Z W; Zhang, X; Lee, L C

    2015-01-01

    A new method for the determination of the Alfven wave energy generated during magnetic reconnection is introduced and used to analyze the results from two-dimensional MHD simulations. It is found that the regions with strong Alfven wave perturbations almost coincide with that where both magnetic-field lines and flow-stream lines are bent, suggesting that this method is reliable for identifying Alfven waves. The magnetic energy during magnetic reconnection is mainly transformed into the thermal energy. The conversion rate to Alfven wave energy from the magnetic energy is strongly correlated to the magnetic reconnection rate. The maximum conversion rate at the time with the peak reconnection rate is found to be only about 4% for the cases with the plasma beta=0.01,0.1, and 1.0.

  12. Theoretical investigation of solar energy conversion and water oxidation catalysis

    E-print Network

    Wang, Lee-Ping

    2011-01-01

    Solar energy conversion and water oxidation catalysis are two great scientific and engineering challenges that will play pivotal roles in a future sustainable energy economy. In this work, I apply electronic structure ...

  13. Photon-Axion Conversion in Intergalactic Magnetic Fields and Cosmological Consequences

    NASA Astrophysics Data System (ADS)

    Mirizzi, Alessandro; Raffelt1, Georg G.; Serpico, Pasquale D.

    Photon-axion conversion induced by intergalactic magnetic fields causes an apparent dimming of distant sources, notably of cosmic distance indicators such as supernovae of type Ia (SNe Ia). We review the impact of this mechanism on the luminosity-redshift relation of SNe Ia, on the dispersion of quasar spectra, and on the spectrum of the cosmic microwave background. The original idea of explaining the apparent dimming of distant SNe Ia without cosmic acceleration is strongly constrained by these arguments. However, the cosmic equation of state extracted from the SN Ia luminosity-redshift relation remains sensitive to this mechanism. For example, it can mimic phantom energy.

  14. Performance testing and economic analysis on a photovoltaic flywheel energy storage and conversion system

    Microsoft Academic Search

    R. D. Hay; A. R. Millner; P. O. Jarvinen

    1980-01-01

    A subscale prototype of a flywheel energy storage and conversion system for use with photovoltaic power systems of residential and intermediate load-center size was designed, built and tested. System design, including details of such key components as magnetic bearings, motor generator, and power conditioning electronics, is described. Performance results of prototype testing are given and indicate that this system is

  15. Research on energy conversion system of floating wave energy converter

    NASA Astrophysics Data System (ADS)

    Zhang, Ya-qun; Sheng, Song-wei; You, Ya-ge; Wu, Bi-jun; Liu, Yang

    2014-03-01

    A wave power device includes an energy harvesting system and a power take-off system. The power take-off system of a floating wave energy device is the key that converts wave energy into other forms. A set of hydraulic power take-off system, which suits for the floating wave energy devices, includes hydraulic system and power generation system. The hydraulic control system uses a special "self-hydraulic control system" to control hydraulic system to release or save energy under the maximum and the minimum pressures. The maximum pressure is enhanced to 23 MPa, the minimum to 9 MPa. Quite a few experiments show that the recent hydraulic system is evidently improved in efficiency and reliability than our previous one, that is expected to be great significant in the research and development of our prototype about wave energy conversion.

  16. Plasmon-assisted radiolytic energy conversion in aqueous solutions

    PubMed Central

    Kim, Baek Hyun; Kwon, Jae W.

    2014-01-01

    The field of conventional energy conversion using radioisotopes has almost exclusively focused on solid-state materials. Herein, we demonstrate that liquids can be an excellent media for effective energy conversion from radioisotopes. We also show that free radicals in liquid, which are continuously generated by beta radiation, can be utilized for electrical energy generation. Under beta radiation, surface plasmon obtained by the metallic nanoporous structures on TiO2 enhanced the radiolytic conversion via the efficient energy transfer between plasmons and free radicals. This work introduces a new route for the development of next-generation power sources. PMID:24918356

  17. Contribution of ocean thermal energy conversion to world energy needs

    NASA Astrophysics Data System (ADS)

    Avery, W. H.; Dugger, G. L.

    1980-07-01

    Ocean Thermal Energy Conversion (OTEC) can provide energy to all countries. It can deliver the energy (1) to regions bordered by warm ocean waters via direct electric-power transmission or (2) to other areas not bordered by warm ocean waters, via an energy-intensive material produced on OTEC plantships cruising on the high seas in the tropics. Ammonia is an outstanding choice for an energy-intensive material because it can (a) replace ammonia now made from natural gas to conserve fuel, (b) serve as a synthetic fuel, or (c) provide an easily transported, storable source of hydrogen for fuel cells to generate electric power where needed anywhere in the world. Costs of OTEC ammonia and of electricity delivered directly or via fuel cells are projected to be competitive with costs of electricity from coal or nuclear plants by 1990, if rapid OTEC development is pursued.

  18. Soft Magnetic Materials in High-Frequency, High-Power Conversion Applications

    E-print Network

    McHenry, Michael E.

    Soft Magnetic Materials in High-Frequency, High-Power Conversion Applications ALEX M. LEARY,1 15236, USA. 3.--e-mail: leary@cmu.edu Advanced soft magnetic materials are needed to match high of megawatt level power electronics. In this article, we examine the role of soft magnetic materials in high

  19. Efficiency of energy conversion for a piezoelectric power harvesting system

    Microsoft Academic Search

    Y. C. Shu; I. C. Lien

    2006-01-01

    This paper studies the energy conversion efficiency for a rectified piezoelectric power harvester. An analytical model is proposed, and an expression of efficiency is derived under steady-state operation. In addition, the relationship among the conversion efficiency, electrically induced damping and ac-dc power output is established explicitly. It is shown that the optimization criteria are different depending on the relative strength

  20. Efficiency of energy conversion for a piezoelectric power harvesting system

    Microsoft Academic Search

    Y C Shu; I C Lien

    2006-01-01

    This paper studies the energy conversion efficiency for a rectified piezoelectric power harvester. An analytical model is proposed, and an expression of efficiency is derived under steady-state operation. In addition, the relationship among the conversion efficiency, electrically induced damping and ac–dc power output is established explicitly. It is shown that the optimization criteria are different depending on the relative strength

  1. Proceedings of the 27th intersociety energy conversion engineering conference

    SciTech Connect

    Not Available

    1992-01-01

    This book contains the proceedings of the 27th Intersociety Energy Conversion Engineering conference. Topics covered include; Conversion Technologies: AMTEC, Heat Engines and Advanced Cycles, Terrestrial Batteries, Terrestrial Electric Propulsion, Heat Pumps, Fuel Cells for Terrestrial Applications, Magnetohydrodynamics, Terrestrial Thermionics, Thermoelectrics, Thermionic Converters.

  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. Analysis of a direct energy conversion system using medium energy helium ions 

    E-print Network

    Carter, Jesse James

    2006-08-16

    A scaled direct energy conversion device was built to convert kinetic energy of singly ionized helium ions into an electric potential by the process of direct conversion. The experiments in this paper aimed to achieve ...

  4. Energy production from biomass (part 2): conversion technologies

    Microsoft Academic Search

    Peter McKendry

    2002-01-01

    The use of biomass to provide energy has been fundamental to the development of civilisation. In recent times pressures on the global environment have led to calls for an increased use of renewable energy sources, in lieu of fossil fuels. Biomass is one potential source of renewable energy and the conversion of plant material into a suitable form of energy,

  5. Optimization of Oxygen Purity for Coal Conversion Energy Reduction

    E-print Network

    Baker, C. R.; Pike, R. A.

    1982-01-01

    The conversion of coal into gaseous and liquid fuels and chemical feedstock will require large quantities of oxygen. This oxygen will be produced in large multi-train air separation plants which will consume about 350 kilowatt hours of energy...

  6. Space electric power design study. [laser energy conversion

    NASA Technical Reports Server (NTRS)

    Martini, W. R.

    1976-01-01

    The conversion of laser energy to electrical energy is discussed. Heat engines in which the laser heats the gas inside the engine through a window as well as heat engines in which the gas is heated by a thermal energy storage reservoir which has been heated by laser radiation are both evaluated, as well as the necessary energy storage, transmission and conversion components needed for a full system. Preliminary system concepts are presented and a recommended development program is outlined. It appears possible that a free displacer Stirling engine operating directly a linear electric generator can convert 65% of the incident laser energy into electricity.

  7. Superconducting energy storage magnet

    NASA Technical Reports Server (NTRS)

    Boom, Roger W. (Inventor); Eyssa, Yehia M. (Inventor); Abdelsalam, Mostafa K. (Inventor); Huang, Xianrui (Inventor)

    1993-01-01

    A superconducting magnet is formed having composite conductors arrayed in coils having turns which lie on a surface defining substantially a frustum of a cone. The conical angle with respect to the central axis is preferably selected such that the magnetic pressure on the coil at the widest portion of the cone is substantially zero. The magnet structure is adapted for use as an energy storage magnet mounted in an earthen trench or tunnel where the strength the surrounding soil is lower at the top of the trench or tunnel than at the bottom. The composite conductor may be formed having a ripple shape to minimize stresses during charge up and discharge and has a shape for each ripple selected such that the conductor undergoes a minimum amount of bending during the charge and discharge cycle. By minimizing bending, the working of the normal conductor in the composite conductor is minimized, thereby reducing the increase in resistance of the normal conductor that occurs over time as the conductor undergoes bending during numerous charge and discharge cycles.

  8. Conversion of laser energy to gas kinetic energy

    NASA Technical Reports Server (NTRS)

    Caledonia, G. E.

    1975-01-01

    Techniques for the gas phase absorption of laser radiation for conversion to gas kinetic energy are discussed. Absorption by inverse Bremsstrahlung, in which laser energy is converted at a gas kinetic rate in a spectrally continuous process, is briefly described, and absorption by molecular vibrational rotation bands is discussed at length. High pressure absorption is proposed as a means of minimizing gas bleaching and dissociation, the major disadvantages of the molecular absorption process. A band model is presented for predicting the molecular absorption spectra in the high pressure absorption region and is applied to the CO molecule. Use of a rare gas seeded with Fe(CO)5 for converting vibrational modes to translation modes is described.

  9. Research and developments on ocean thermal energy conversion

    Microsoft Academic Search

    C. M. Wang; A. A. Yee; H. Krock; Z. Y. Tay

    2011-01-01

    Ocean thermal energy conversion (OTEC) is a very promising source of clean and renewable energy for our planet. This review article presents the research and developments on OTEC with regard to energy utilisation, platform design and mooring system, heat exchanger system and environmental impact. It also includes very recent developments in realising the construction of large scale OTEC facilities.

  10. Energy production from biomass (Part 2): Conversion technologies.

    PubMed

    McKendry, Peter

    2002-05-01

    The use of biomass to provide energy has been fundamental to the development of civilisation. In recent times pressures on the global environment have led to calls for an increased use of renewable energy sources, in lieu of fossil fuels. Biomass is one potential source of renewable energy and the conversion of plant material into a suitable form of energy, usually electricity or as a fuel for an internal combustion engine, can be achieved using a number of different routes, each with specific pros and cons. A brief review of the main conversion processes is presented, with specific regard to the production of a fuel suitable for spark ignition gas engines. PMID:12058830

  11. Energy Conversion and Storage Program: 1992 Annual report

    SciTech Connect

    Cairns, E.J.

    1993-06-01

    This report is the 1992 annual progress report for the Energy Conversion and Storage Program, a part of the Energy and Environment Division of the Lawrence Berkeley Laboratory. Work described falls into three broad areas: electrochemistry; chemical applications; and materials applications. The Energy Conversion and Storage Program applies principles of chemistry and materials science to solve problems in several areas: (1) production of new synthetic fuels, (2) development of high-performance rechargeable batteries and fuel cells, (3) development of advanced thermochemical processes for energy conversion, (4) characterization of complex chemical processes and chemical species, and (5) study and application of novel materials for energy conversion and transmission. Projects focus on transport-process principles, chemical kinetics, thermodynamics, separation processes, organic and physical chemistry, novel materials, and advanced methods of analysis. Electrochemistry research aims to develop advanced power systems for electric vehicle and stationary energy storage applications. Chemical applications research includes topics such as separations, catalysis, fuels, and chemical analyses. Included in this program area are projects to develop improved, energy-efficient methods for processing product and waste streams from synfuel plants, coal gasifiers, and biomass conversion processes. Materials applications research includes evaluation of the properties of advanced materials, as well as development of novel preparation techniques. For example, techniques such as sputtering, laser ablation, and poised laser deposition are being used to produce high-temperature superconducting films.

  12. Controlling Energy Costs with Coal Conversion 

    E-print Network

    Sadowski, R. S.; von Hippel, C. S.

    1984-01-01

    Even with a decade of substantial energy reduction in America's manufacturing plants and a temporary 'oil glut', energy often represents the largest plant expense, higher than labor or raw materials. Energy is not only a major plant expense...

  13. The Benefits of Planar Magnetics in OF Power Conversion

    E-print Network

    : thin copper foils which are manufactured as flat conductors on Printed Circuit Boards (PCB) or self) Exploded view of a Planar Magnetics (PM) transformer. #12;s. Ben-Yaakov, The Benefits of Planar Magnetics

  14. Cogeneration Technology Alternatives Study (CTAS). Volume 4: Energy conversion systems

    NASA Technical Reports Server (NTRS)

    Brown, D. H.; Gerlaugh, H. E.; Priestley, R. R.

    1980-01-01

    Industrial processes from the largest energy consuming sectors were used as a basis for matching a similar number of energy conversion systems that are considered as candidate which can be made available by the 1985 to 2000 time period. The sectors considered included food, textiles, lumber, paper, chemicals, petroleum, glass, and primary metals. The energy conversion systems included steam and gas turbines, diesels, thermionics, stirling, closed-cycle and steam injected gas turbines, and fuel cells. Fuels considered were coal, both coal and petroleum-based residual and distillate liquid fuels, and low Btu gas obtained through the on-site gasification of coal. An attempt was made to use consistent assumptions and a consistent set of ground rules specified by NASA for determining performance and cost. The advanced and commercially available cogeneration energy conversion systems studied in CTAS are fined together with their performance, capital costs, and the research and developments required to bring them to this level of performance.

  15. Superconducting magnetic energy storage

    SciTech Connect

    Hassenzahl, W.

    1988-08-01

    Recent programmatic developments in Superconducting Magnetic Energy Storage (SMES) have prompted renewed and widespread interest in this field. In mid 1987 the Defense Nuclear Agency, acting for the Strategic Defense Initiative Office, issued a request for proposals for the design and construction of SMES Engineering Test Model (ETM). Two teams, one led by Bechtel and the other by Ebasco, are now engaged in the first phase of the development of a 10 to 20 MWhr ETM. This report presents the rationale for energy storage on utility systems, describes the general technology of SMES, and explains the chronological development of the technology. The present ETM program is outlined; details of the two projects for ETM development are described in other papers in these proceedings. The impact of high T/sub c/ materials on SMES is discussed. 69 refs., 3 figs., 3 tabs.

  16. Nanostructured materials for advanced energy conversion and storage devices

    Microsoft Academic Search

    Antonino Salvatore Aricò; Peter Bruce; Bruno Scrosati; Jean-Marie Tarascon; Walter van Schalkwijk

    2005-01-01

    New materials hold the key to fundamental advances in energy conversion and storage, both of which are vital in order to meet the challenge of global warming and the finite nature of fossil fuels. Nanomaterials in particular offer unique properties or combinations of properties as electrodes and electrolytes in a range of energy devices. This review describes some recent developments

  17. Ocean thermal energy conversion: report to congress - fiscal year 1982

    SciTech Connect

    Not Available

    1983-03-31

    National Oceanic and Atmospheric Administration (NOAA) activities related to ocean thermal energy conversion (OTEC) during fiscal year 1982 are described. The agency focus has been in the areas of providing ocean engineering and technical assistance to the Department of Energy (DOE), in streamlining the administration of the Federal OTEC licensing system, and in environmental assistance.

  18. Wind energy conversion systems using fuzzy sliding mode control

    Microsoft Academic Search

    Qi Chen; LiangHai Chen; LinGao Wang

    2011-01-01

    The paper describes a manner in which the energy-reliability optimization of wind energy conversion system's operation can be achieved by means of the fuzzy sliding mode control. An appropriate sliding surface has been found in the speed-power plane, which allows the operation more or less close to the optimal regimes characteristic. What is more, by torque controlling the generator, an

  19. Wind Energy Conversion Systems. A Unit of Instruction.

    ERIC Educational Resources Information Center

    Greenwald, Martin

    The number of secondary schools, colleges, and universities offering courses in wind energy machine construction, repair, and installation, continues to increase. It is the purpose of this unit to include the study of wind energy conversion systems (WECS) as an integral part of related vocational and technical curriculum materials. The unit's…

  20. Thermoelectric, thermionic and thermophotovoltaic energy conversion Ali Shakouri

    E-print Network

    more easily. Linear/Nolinear Transport Regime Conventional thermoelectric coolers and power generators is for thermoelectric cooling and power generation applications. Energy Hot electron Cold electron Cathode Barrier AnodeThermoelectric, thermionic and thermophotovoltaic energy conversion Ali Shakouri Jack Baskin School

  1. Improving wind power quality using an integrated Wind Energy Conversion and Storage System (WECSS)

    Microsoft Academic Search

    Nicholas P. W. Strachan; Dragan Jovcic

    2008-01-01

    This paper details the modeling, controller development, simulation and analysis of an integrated 2MW variable-speed Wind Energy Conversion and Storage System (WECSS) in dynamic simulation software PSCAD. The WECSS presented consists of a pitch controlled wind turbine directly driving a 2MW permanent magnet synchronous generator (PMSG). The PMSG is connected to its host power system via a controlled full-scale power

  2. Pin stack array for thermoacoustic energy conversion

    DOEpatents

    Keolian, Robert M. (Monterey, CA); Swift, Gregory W. (Santa Fe, NM)

    1995-01-01

    A thermoacoustic stack for connecting two heat exchangers in a thermoacoustic energy converter provides a convex fluid-solid interface in a plane perpendicular to an axis for acoustic oscillation of fluid between the two heat exchangers. The convex surfaces increase the ratio of the fluid volume in the effective thermoacoustic volume that is displaced from the convex surface to the fluid volume that is adjacent the surface within which viscous energy losses occur. Increasing the volume ratio results in an increase in the ratio of transferred thermal energy to viscous energy losses, with a concomitant increase in operating efficiency of the thermoacoustic converter. The convex surfaces may be easily provided by a pin array having elements arranged parallel to the direction of acoustic oscillations and with effective radial dimensions much smaller than the thicknesses of the viscous energy loss and thermoacoustic energy transfer volumes.

  3. Carbon nanomaterials for advanced energy conversion and storage.

    PubMed

    Dai, Liming; Chang, Dong Wook; Baek, Jong-Beom; Lu, Wen

    2012-04-23

    It is estimated that the world will need to double its energy supply by 2050. Nanotechnology has opened up new frontiers in materials science and engineering to meet this challenge by creating new materials, particularly carbon nanomaterials, for efficient energy conversion and storage. Comparing to conventional energy materials, carbon nanomaterials possess unique size-/surface-dependent (e.g., morphological, electrical, optical, and mechanical) properties useful for enhancing the energy-conversion and storage performances. During the past 25 years or so, therefore, considerable efforts have been made to utilize the unique properties of carbon nanomaterials, including fullerenes, carbon nanotubes, and graphene, as energy materials, and tremendous progress has been achieved in developing high-performance energy conversion (e.g., solar cells and fuel cells) and storage (e.g., supercapacitors and batteries) devices. This article reviews progress in the research and development of carbon nanomaterials during the past twenty years or so for advanced energy conversion and storage, along with some discussions on challenges and perspectives in this exciting field. PMID:22383334

  4. Optical Materials Technology for Energy Efficiency and Solar Energy Conversion XIV

    Microsoft Academic Search

    Carl M. Lampert; Satyen K. Deb; Claes G. Granqvist

    1995-01-01

    This volume gives the reader an update on the progress in the field of optical materials research for energy efficiency and solar energy conversion applications. The field covers a wide range of technology for the control, modification, and conversion of radiant energy. Currently, there is very strong activity in the development of materials for the modification of energy-propagating through glazings.

  5. Energy Conversion, Mixing Energy, and Neutral Surfaces with a Nonlinear Equation of State

    E-print Network

    Nycander, Jonas

    Energy Conversion, Mixing Energy, and Neutral Surfaces with a Nonlinear Equation of State JONAS energy, it is generally assumed that it does not produce a restoring buoyancy force. However, it is here effect) such a neutral displacement is accompanied by a conversion between internal energy E

  6. Thermionic energy conversion (TEC) topping thermoelectrics

    SciTech Connect

    Morris, J.F.

    1981-01-01

    Long-respected international experts on thermoelectrics (Dixon, Ertl and Goldsmid supported by Ure) determine the probable maximum figure of merit (ZT) for fully matured thermoelectric generators as about unity from ordiary temperatures to 2000 K. Thus the maximum efficiency for fully matured thermoelectrics would be approximately 0.414 (l - r/sub T/)/(1.414 + r/sub T/) where r/sub T/ is the ratio of cold and hot junction temperatures. This limitation contrasts with the recent burst of enthusiasm for high-temperature thermoelectrics - based on calculated figures of merit and efficiencies that increase more and more rapidly with rising temperatures. Unfortunately these calculations neglect internal radiation effects which diminish thermoelectric figures of merit significantly at 1000 K and substantially at 2000 K: The effective thermal-conductivity contribution of intrathermoelectric radiative dissipation increases with the third power of temperature. Therefore the quotation from Thermoelectricy: Science and Engineering by Heikes and Ure apparently still prevails: ...thermoelectric devices appear difficult to extend in the direction of high temperature, while thermionic devices become inefficient at low temperature. Accordingly consideration of thermoelectric power generation with high-temperature heat sources should include utilization of TEC topping thermoelectrics. However TEC alone or TEC topping more-efficient conversion systems like steam or gas turbines, combined cycles or Stirling engines would be more desirable generally.

  7. Efficient Electrochemical CO2 Conversion Powered by Renewable Energy.

    PubMed

    Kauffman, Douglas R; Thakkar, Jay; Siva, Rajan; Matranga, Christopher; Ohodnicki, Paul R; Zeng, Chenjie; Jin, Rongchao

    2015-07-22

    The catalytic conversion of CO2 into industrially relevant chemicals is one strategy for mitigating greenhouse gas emissions. Along these lines, electrochemical CO2 conversion technologies are attractive because they can operate with high reaction rates at ambient conditions. However, electrochemical systems require electricity, and CO2 conversion processes must integrate with carbon-free, renewable-energy sources to be viable on larger scales. We utilize Au25 nanoclusters as renewably powered CO2 conversion electrocatalysts with CO2 ? CO reaction rates between 400 and 800 L of CO2 per gram of catalytic metal per hour and product selectivities between 80 and 95%. These performance metrics correspond to conversion rates approaching 0.8-1.6 kg of CO2 per gram of catalytic metal per hour. We also present data showing CO2 conversion rates and product selectivity strongly depend on catalyst loading. Optimized systems demonstrate stable operation and reaction turnover numbers (TONs) approaching 6 × 10(6) molCO2 molcatalyst(-1) during a multiday (36 h total hours) CO2 electrolysis experiment containing multiple start/stop cycles. TONs between 1 × 10(6) and 4 × 10(6) molCO2 molcatalyst(-1) were obtained when our system was powered by consumer-grade renewable-energy sources. Daytime photovoltaic-powered CO2 conversion was demonstrated for 12 h and we mimicked low-light or nighttime operation for 24 h with a solar-rechargeable battery. This proof-of-principle study provides some of the initial performance data necessary for assessing the scalability and technical viability of electrochemical CO2 conversion technologies. Specifically, we show the following: (1) all electrochemical CO2 conversion systems will produce a net increase in CO2 emissions if they do not integrate with renewable-energy sources, (2) catalyst loading vs activity trends can be used to tune process rates and product distributions, and (3) state-of-the-art renewable-energy technologies are sufficient to power larger-scale, tonne per day CO2 conversion systems. PMID:26121278

  8. Effects of semiconduction on electromechanical energy conversion in piezoelectrics

    NASA Astrophysics Data System (ADS)

    Li, Peng; Jin, Feng; Yang, Jiashi

    2015-02-01

    We study the effect of semiconduction on mechanical-to-electrical energy conversion through a theoretical analysis on the thickness-extensional vibration of a piezoelectric semiconductor plate driven mechanically. An analytical solution is obtained. A ZnO plate is used as a numerical example. Results show that both the electrical output power and the energy conversion efficiency are sensitive to semiconduction at a moderate carrier density of 1015 m?3, and that the effect of the dissipation due to semiconduction can be comparable to the effect of material damping when the material quality factor is in the usual range of 102–103.

  9. Guidelines in Wave Energy Conversion System Design

    E-print Network

    Guiberteau, K. L.; Liu, Y.; Lee, J.; Kozman, T.

    2014-01-01

    This paper presents an investigational study on wave energy converters (WECs). The types of WEC available from the market are studied first. The design considerations for implementing a WEC in the Gulf of Mexico (GOM) are then evaluated...

  10. The plasmatron: Advanced mode thermionic energy conversion

    NASA Technical Reports Server (NTRS)

    Hansen, L. K.; Hatch, G. L.; Rasor, N. S.

    1976-01-01

    A theory of the plasmatron was developed. Also, a wide range of measurements were obtained with two versatile, research devices. To gain insight into plasmatron performance, the experimental results are compared with calculations based on the theoretical model of plasmatron operation. Results are presented which show that the plasma arc drop of the conventional arc (ignited) mode converter can be suppressed by use of an auxiliary ion source. The improved performance, however, is presently limited to low current densities because of voltage losses due to plasma resistance. This resistance loss could be suppressed by an increase in the plasma electron temperature or a decrease in spacing. Plasmatron performance characteristics for both argon and cesium are reported. The argon plasmatron has superior performance. Results are also presented for magnetic cutoff effects and for current distributing effects. These are shown to be important factors for the design of practical devices.

  11. 440 IEEE Transactions on Energy Conversion, Vol. 14, No. 3, September 1999 MultipleReferenceFrameAnalysis ofNon-sinusoidalBrushlessDCDrives

    E-print Network

    Chapman, Patrick

    -magnet synchronous machine pm has b~ned magnets and which are idly salient, and those with surface mounted magnets440 IEEE Transactions on Energy Conversion, Vol. 14, No. 3, September 1999 MultipleReferenceFrameAnalysis has the desirable features of being valid for transient and steady-state analysis as well as having

  12. Guidelines in Wave Energy Conversion System Design 

    E-print Network

    Guiberteau, K. L.; Liu, Y.; Lee, J.; Kozman, T.

    2014-01-01

    student for the Industrial Assessment Center at the University of Louisiana at Lafayette, and her research interests include energy management, integrated product and process design, and wave energy. Email: kguiberteau@gmail.com Theodore A. Kozman... uses large arrays to provide for higher demands [13]. According to the Ocean Power Technology website (www.oceanpowertechnologies.com), the company is planning on building a commercial unit off the coast of Spain, which will generate 1.39 MW...

  13. Emerging electrochemical energy conversion and storage technologies

    PubMed Central

    Badwal, Sukhvinder P. S.; Giddey, Sarbjit S.; Munnings, Christopher; Bhatt, Anand I.; Hollenkamp, Anthony F.

    2014-01-01

    Electrochemical cells and systems play a key role in a wide range of industry sectors. These devices are critical enabling technologies for renewable energy; energy management, conservation, and storage; pollution control/monitoring; and greenhouse gas reduction. A large number of electrochemical energy technologies have been developed in the past. These systems continue to be optimized in terms of cost, life time, and performance, leading to their continued expansion into existing and emerging market sectors. The more established technologies such as deep-cycle batteries and sensors are being joined by emerging technologies such as fuel cells, large format lithium-ion batteries, electrochemical reactors; ion transport membranes and supercapacitors. This growing demand (multi billion dollars) for electrochemical energy systems along with the increasing maturity of a number of technologies is having a significant effect on the global research and development effort which is increasing in both in size and depth. A number of new technologies, which will have substantial impact on the environment and the way we produce and utilize energy, are under development. This paper presents an overview of several emerging electrochemical energy technologies along with a discussion some of the key technical challenges. PMID:25309898

  14. Supramolecular Structures for Photochemical Energy Conversion

    SciTech Connect

    Gust, Devens; Moore, Thomas A.; Moore, Ana L.

    2003-08-26

    OAK B188 The goal of this project is to mimic the energy transduction processes by which photosynthetic organisms harvest sunlight and convert it to forms of energy that are more easily used and stored. The results may lead to new technologies for solar energy harvesting based on the natural photosynthetic process. They may also enrich our understanding and control of photosynthesis in living organisms, and lead to methods for increasing natural biomass production, carbon dioxide removal, and oxygen generation. In our work to date, we have learned how to make synthetic antenna and reaction center molecules that absorb light and undergo photoinduced electron transfer to generate long-lived, energetic charge-separated states. We have assembled a prototype system in which artificial reaction centers are inserted into liposomes (artificial cell-like constructs), where they carry out light-driven transmembrane translocation of hydrogen ions to generate proton motive force. By insertion of natural ATP synthase into the liposomal bilayer, this proton motive force has been used to power the synthesis of ATP. ATP is a natural biological energy currency. We are carrying out a systematic investigation of these artificial photosynthetic energy harvesting constructs in order to understand better how they operate. In addition, we are exploring strategies for reversing the direction of the light-powered proton pumping. Most recently, we have extended these studies to develop a light-powered transmembrane calcium ion pump that converts sunlight into energy stored as a calcium ion concentration gradient across a lipid bilayer.

  15. Dynamic switching conversion for piezoelectric energy harvesting systems

    Microsoft Academic Search

    Aldo Romani; Cinzia Tamburini; Alessandro Golfarelli; Rossano Codeluppi; Enrico Sangiorgi; Marco Tartagni; Rudi Paolo Paganelli

    2008-01-01

    The current advances in ultra-low power design let foresee great opportunities in energy harvesting platforms for self-powered systems. This paper presents a switching conversion scheme based on active control for harvesting energy with a higher efficiency than traditional approaches. The approach has been validated for piezoelectric energy harvesters with mixed-signal circuital simulations of non-linear equivalent electromechanical systems and a prototype

  16. The NASA program in Space Energy Conversion Research and Technology

    NASA Astrophysics Data System (ADS)

    Mullin, J. P.; Flood, D. J.; Ambrus, J. H.; Hudson, W. R.

    The considered Space Energy Conversion Program seeks advancement of basic understanding of energy conversion processes and improvement of component technologies, always in the context of the entire power subsystem. Activities in the program are divided among the traditional disciplines of photovoltaics, electrochemistry, thermoelectrics, and power systems management and distribution. In addition, a broad range of cross-disciplinary explorations of potentially revolutionary new concepts are supported under the advanced energetics program area. Solar cell research and technology are discussed, taking into account the enhancement of the efficiency of Si solar cells, GaAs liquid phase epitaxy and vapor phase epitaxy solar cells, the use of GaAs solar cells in concentrator systems, and the efficiency of a three junction cascade solar cell. Attention is also given to blanket and array technology, the alkali metal thermoelectric converter, a fuel cell/electrolysis system, and thermal to electric conversion.

  17. Thermoelectric, thermionic and thermophotovoltaic energy conversion

    Microsoft Academic Search

    A. Shakouri

    2005-01-01

    Key characteristics of thermoelectric, ballistic thermionic and quasi diffusive thermionic energy converters are compared. First, the main assumptions used to derive the linear Boltzmann transport equations for electrons are examined and the possibility that a higher order transport coefficient may become relevant is discussed. In the linear transport regime, there is a fundamental trade off between high Seebeck coefficient and

  18. 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

  19. Photonic design for efficient solid state energy conversion

    Microsoft Academic Search

    Mukul Agrawal

    2009-01-01

    The efficiency of conversion between electrical and photonic energy in optoelectronic devices such as light-emitting diodes, photodetectors and solar cells is strongly affected by the photonic modes supported by the device structure. In this thesis, we show how tuning of the local photon density of states in subwavelength structures can be used to optimize device performance. The first part of

  20. Quantitative evaluation of Ocean Thermal Energy Conversion (OTEC): Executive briefing

    NASA Astrophysics Data System (ADS)

    Gritton, E. C.; Pei, R. Y.; Hess, R. W.

    1980-08-01

    The results of an independent quantitative evaluation of Ocean Thermal Energy Conversion (OTEC) for central station applications are summarized. A central station power plant located in the Gulf of Mexico and delivering power to the mainland United States was emphasized. The evaluation of OTEC is based on three important issues: resource availability, technical feasibility, and cost.

  1. Proceedings of the 27th intersociety energy conversion engineering conference

    SciTech Connect

    Not Available

    1992-01-01

    This book contains the proceedings of the 27th Intersociety Energy Conversion Engineering Conference. Topics included: Stirling Cycle Analysis; Stirling Cycle Models; Stirling Refrigerators/Heat Pumps and Cryocoolers; Domestic Policy; Efficiency/Conservation; Stirling Solar Terrestrial; Stirling Component Technology; Environmental Impacts; Renewable Resource Systems; Stirling Power Generation; Stirling Heat Transport System Technology; and Stirling Cycle Loss Understanding.

  2. Photochemical aspects of solar energy conversion and storage

    Microsoft Academic Search

    J. R. Bolton

    1979-01-01

    The paper defines qualitatively and quantitatively the thermodynamic and kinetic limits on the photochemical conversion and storage of solar energy as it is received on the earth's surface. Attention is given to an evaluation of a number of possible reactions, with special emphasis on the generation of solar fuels such as hydrogen from water and the generation of electricity. The

  3. Linear mode conversion of Langmuir/z-mode waves to radiation in plasmas with various magnetic field strength

    SciTech Connect

    Kim, Eun-Hwa; Johnson, Jay R. [Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)] [Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States); Cairns, Iver H. [School of Physics, University of Sydney, Sydney, New South Wales 2002 (Australia)] [School of Physics, University of Sydney, Sydney, New South Wales 2002 (Australia)

    2013-12-15

    Linear mode conversion of Langmuir/z waves to electromagnetic radiation near the plasma and upper hybrid frequency in the presence of density gradients is potentially relevant to type II and III solar radio bursts, ionospheric radar experiments, pulsars, and continuum radiation for planetary magnetospheres. Here, we study mode conversion in warm, magnetized plasmas using a numerical electron fluid simulation code when the density gradient has a wide range of angle, ?, to the ambient magnetic field, B{sub 0}, for a range of incident Langmuir/z wavevectors. Our results include: (1) Left-handed polarized ordinary (oL) and right-handed polarized extraordinary (xR) mode waves are produced in various ranges of ? for ?{sub 0} = (?L/c){sup 1/3}(?{sub ce}/?) < 1.5, where ?{sub ce} is the (angular) electron cyclotron frequency, ? is the angular wave frequency, L is the length scale of the (linear) density gradient, and c is the speed of light; (2) the xR mode is produced most strongly in the range, 40° < ? < 60°, for intermediately magnetized plasmas with ?{sub 0} = 1.0 and 1.5, while it is produced over a wider range, 0° ? ? ? 90°, for weakly magnetized plasmas with ?{sub 0} = 0.1 and 0.7; (3) the maximum total conversion efficiencies for wave power from the Langmuir/z mode to radiation are of order 50%–99% and the corresponding energy conversion efficiencies are 5%–14% (depending on the adiabatic index ? and ? = T{sub e}/m{sub e}c{sup 2}, where T{sub e} is the electron temperature and m{sub e} is the electron) for various ?{sub 0}; (4) the mode conversion window becomes wider as ?{sub 0} and ? increase. Hence, the results in this paper confirm that linear mode conversion under these conditions can explain the weak total circular polarization of interplanetary type II and III solar radio bursts because a strong xR mode can be generated via linear mode conversion near ? ? 45°.

  4. Piezoelectric ribbons printed onto rubber for flexible energy conversion.

    PubMed

    Qi, Yi; Jafferis, Noah T; Lyons, Kenneth; Lee, Christine M; Ahmad, Habib; McAlpine, Michael C

    2010-02-10

    The development of a method for integrating highly efficient energy conversion materials onto stretchable, biocompatible rubbers could yield breakthroughs in implantable or wearable energy harvesting systems. Being electromechanically coupled, piezoelectric crystals represent a particularly interesting subset of smart materials that function as sensors/actuators, bioMEMS devices, and energy converters. Yet, the crystallization of these materials generally requires high temperatures for maximally efficient performance, rendering them incompatible with temperature-sensitive plastics and rubbers. Here, we overcome these limitations by presenting a scalable and parallel process for transferring crystalline piezoelectric nanothick ribbons of lead zirconate titanate from host substrates onto flexible rubbers over macroscopic areas. Fundamental characterization of the ribbons by piezo-force microscopy indicates that their electromechanical energy conversion metrics are among the highest reported on a flexible medium. The excellent performance of the piezo-ribbon assemblies coupled with stretchable, biocompatible rubber may enable a host of exciting avenues in fundamental research and novel applications. PMID:20102189

  5. Proceedings of the 33. intersociety energy conversion engineering conference

    SciTech Connect

    Anghaie, S. [ed.

    1998-07-01

    These papers were presented at the Intersociety Energy Conversion Engineering Conference, August of 1998. The topics of the papers included aerospace power analyses and simulation, space energy conversion, applications and requirements for space power systems, space solar power, terrestrial energy, aerospace batteries, aerospace power management, aerospace power electronics, aircraft power, dual use technologies, electric propulsion, wireless energy transmission, terrestrial thermoelectric, heat pumps, innovative concepts, stirling engine and heat pump applications, stirling engines and components, stirling analysis, magnetohydrodynamics, thermionics, AMTEC advanced modular power systems, advanced cycles, co-generation and heat engines, alkali batteries, other batteries, terrestrial fuel cells, fuel cells in distributed generation systems, fuel cells in buildings applications, systems modeling and analysis of fuel cells, polymer electrolyte fuel cells, fuel processing for fuel cells, alternative fuel vehicles, clean energy options, electric vehicles, energy and the environment, thermal storage, building energy systems, concepts in cold fusion, power systems control, electric power systems, simulation and modeling, nuclear power systems, fossil fuels, energy policy, deregulation of electric utilities, photovoltaic energy technology, modeling and simulation, advanced solar house and building, wind energy, hydrogen energy systems, energy from waste and biomass, geothermal, cryogenic heat transfer, heat pipes, loop heat pipes, and capillary pumped loops, spacecraft and aircraft thermal control, numerical analysis and code verification, two phase heat and mass transfer.

  6. Energy Conversion Using New Thermoelectric Generator

    E-print Network

    Savelli, Guillaume; Bablet, Jacqueline; Salvi, C; Fournier, J M

    2007-01-01

    During recent years, microelectronics helped to develop complex and varied technologies. It appears that many of these technologies can be applied successfully to realize Seebeck micro generators: photolithography and deposition methods allow to elaborate thin thermoelectric structures at the micro-scale level. Our goal is to scavenge energy by developing a miniature power source for operating electronic components. First Bi and Sb micro-devices on silicon glass substrate have been manufactured with an area of 1cm2 including more than one hundred junctions. Each step of process fabrication has been optimized: photolithography, deposition process, anneals conditions and metallic connections. Different device structures have been realized with different micro-line dimensions. Each devices performance will be reviewed and discussed in function of their design structure.

  7. Control of Melt Conversion Using Traveling Magnetic Fields

    NASA Technical Reports Server (NTRS)

    Mazurruk, Konstantin; Rose, M. Franklin (Technical Monitor)

    2000-01-01

    An axisymmetric traveling magnetic wave induces a meridional base flow in a cylindrical zone of an electrically conducting liquid. This remotely induced flow can be conveniently controlled, in magnitude and direction, and can have benefits for crystal growth applications. In particular, it can be used to significantly offset natural convection. Theoretical basics of this new technological method are presented.

  8. Nano-photocatalysts in microfluidics, energy conversion and environmental applications.

    PubMed

    Parmar, Jemish; Jang, Seungwook; Soler, Lluís; Kim, Dong-Pyo; Sánchez, Samuel

    2015-06-01

    Extensive studies have been carried out on photocatalytic materials in recent years as photocatalytic reactions offer a promising solution for solar energy conversion and environmental remediation. Currently available commercial photocatalysts still lack efficiency and thus are economically not viable for replacing traditional sources of energy. This article focuses on recent developments in novel nano-photocatalyst materials to enhance photocatalytic activity. Recent reports on optofluidic systems, new synthesis of photocatalytic composite materials and motile photocatalysts are discussed in this article. PMID:25902335

  9. SPS energy conversion and power management workshop. Final report

    SciTech Connect

    Not Available

    1980-06-01

    In 1977 a four year study, the concept Development and Evaluation Program, was initiated by the US Department of Energy and the National Aeronautics and Space Administration. As part of this program, a series of peer reviews were carried out within the technical community to allow available information on SPS to be sifted, examined and, if need be, challenged. The SPS Energy Conversion and Power Management Workshop, held in Huntsville, Alabama, February 5 to 7, 1980, was one of these reviews. The results of studies in this particular field were presented to an audience of carefully selected scientists and engineers. This first report summarizes the results of that peer review. It is not intended to be an exhaustive treatment of the subject. Rather, it is designed to look at the SPS energy conversion and power management options in breadth, not depth, to try to foresee any troublesome and/or potentially unresolvable problems and to identify the most promising areas for future research and development. Topics include photovoltaic conversion, solar thermal conversion, and electric power distribution processing and power management. (WHK)

  10. Direct-energy-conversion implications of Space Nuclear Reactors

    SciTech Connect

    Morris, J.F.

    1982-08-01

    The Air Force, NASA and DOE stress space-nuclear reactor (SNR) needs in 1981 IECEC papers. SNR proposals range from 10-to-100kW /SUB e/,s with thermoelectrics through the fractional-to-several MW /SUB e/ 's with thermionic conversion to rotating bed-reactor (RBR) and NERVA ultraversions. SNR direct conversion comprises thermionic and thermoelectric generation (TEG). Thermionic energy conversion (TEC) pervades the pre-1973 in-core and out-of-core-heat-pipe concepts. SPAR and SP-100 focus on thermoelectrics because of ostensible fuel-temperature limits. A Rasor Associates mini-heat-pipe reactor verifies again the high-power capability of this SNR type--as well as TEC advantages over TEG. Finally with about 2000K effluents, directly from RBR's, NERVA's or from MHD used with them, TEC could also produce very high power levels. This paper outlines SNR needs, discusses some proposed concepts and recommends future technology programs.

  11. A wideband magnetic energy harvester

    NASA Astrophysics Data System (ADS)

    Zhang, C. L.; Chen, W. Q.

    2010-03-01

    A wideband magnetic energy harvester is proposed by using a number of multiferroic composite fibers of different lengths which are connected in parallel or series. The structural theory is employed to characterize the magnetoelectroelastic behavior of the fibers. A global circuit analysis is then performed. It is shown that such a structure of energy harvester is capable of collecting the ambient magnetic energy over a wide frequency range.

  12. Giant magnetoelectric effect in magnet-cymbal-solenoid current-to-voltage conversion device

    Microsoft Academic Search

    Min Zeng; Siu Wing; Helen Lai Wa Chan

    2010-01-01

    A giant magnetoelectric (ME) effect is reported in a current-to-voltage (I-to-V) conversion device formed by sandwiching a PZT piezoelectric cymbal transducer between an NdFeB magnet and a Fe-core solenoid. The observed ME effect results from the direct coupling of the electromagnetically induced attractive-repellent force effect in the magnet-solenoid assembly with the amplified piezoelectric effect in the cymbal transducer. The device

  13. Mode Conversion and Energy Partitioning at Active Volcanoes

    NASA Astrophysics Data System (ADS)

    Yamamoto, M.; Nishimura, T.; Tsutsui, T.; Iguchi, M.

    2010-12-01

    It has recently been shown that correlations of seismic noise and coda wave provide rich information on the Green’s function between observation sites. Such technique, known as seismic interferometry, are often based on the assumption of equipartitioning, and thus the energy partitioning of diffuse waves has been widely studies from the view points of wave theory and experimental/field observations. Recently, using an active seismic experiment at Asama volcano, Japan, Yamamoto and Sato (2010) quantified the scattering characteristics of multiple scattering and conversion scattering, and pointed out that P energy from active sources is rapidly converted to S energy and it takes only a few seconds that the local energy ratio approaches the equipartition based on the radiative transfer modeling using the estimated scattering parameters. To obtain a direct evidence of mode conversion and energy partitioning in shallow heterogeneous structure of active volcanoes and have implications for seismic interferometry, we conducted a seismic array observation in Nov. 2008 as a part of an active seismic experiment at Sakurajima volcano, Japan. We deployed a small square-shaped array composed of four three-component short-period seismometers, and decomposed the observed wavefield into P and S energies. Observed seismograms are characterized by spindle-like envelopes having small P-onsets and long codas lasting for more than 10 sec, and the decomposed P and S energies show the following characteristics in high frequency bands (4-8Hz and 8-12Hz): S energy rapidly increase just after the arrival of direct P wave, and S energy exceed P energy about 2 sec after the first arrival; the ratio of P and S energies make the gradual transition to the equipartition over about 5-10 sec. These behaviors can be well explained by the radiative transfer theory including mode conversion in a medium having the mean free path of about 1km. Another interesting finding from the array observation is that the local energy ratios in ambient noise and coda wave are almost the same. The fact indicates that even the ambient noise, which is basically generated by random excitation of ballistic waves, is in equipartition state due to strong scattering in heterogeneous volcanic environment. Observed good correlation between the site amplification factors estimated from ambient noise and coda wave also supports the hypothesis that these wave fields share almost same composition. These results suggest that the mode conversion and multiple scattering have an indispensable effect on the seismic wave propagation in heterogeneous volcanic environments. We expect our results on the energy partitioning and its transition to be of help to justify the applicability of seismic interferometry and pseudo-reflection method at active volcanoes.

  14. Linear generators for direct-drive wave energy conversion

    Microsoft Academic Search

    H. Polinder; B. C. Mecrow; A. G. Jack; P. Dickinson; M. A. Mueller

    2003-01-01

    The Archimedes Wave Swing (AWS) is a system that converts ocean wave energy into electric energy. The goal of the research described in this paper is to identify the most suitable generator type for this application. Of the more conventional generator types, the three-phase permanent-magnet synchronous generator with iron in both stator and translator is most suitable, because it is

  15. A study of water electrolysis with photovoltaic solar energy conversion

    NASA Astrophysics Data System (ADS)

    Carpetis, C.

    The performance of the hydrogen production system consisting of the photovoltaic array and the water electrolysis unit is studied. The results of the calculation are compared with available experimental data and the performance of a hydrogen production plant by means of photovoltaic solar energy conversion is determined for two typical locations. A method for the estimation of the power matching conditions of the system solar array electrolysis unit is formulated to allow conclusions of general validity.

  16. Solar energy conversion: Solid-state physics aspects

    Microsoft Academic Search

    B. O. Seraphin

    1979-01-01

    Solid-state aspects of solar energy conversion systems are discussed, with attention given to spectrally selective surfaces, carrier lifetimes in silicon, solar photoelectrolysis with semiconductor electrodes, heterojunction phenomena and interfacial defects in photovoltaic converters, and the Cu2S\\/CdS cell. The reviews include discussions of chemical vapor deposition of silicon, black-chrome electroplated coatings and semiconductor cermet films for photothermal converters, highly doped, highly

  17. The near-term prospectives for photovoltaic solar energy conversion

    Microsoft Academic Search

    M. Wolf

    1977-01-01

    Changes in the price\\/demand curve for photovoltaic energy conversion devices during the next five years, as well as technological advances affecting the cost of photocells, are discussed. Innovations such as the black or nonreflective silicon solar cell, or cells employing thin (50- to 100-micron) silicon layers and Ceria-doped glass covers are described; GaAs cells are also mentioned. A mathematical model

  18. Energy: A continuing bibliography with indexes, February 1975. [solar energy, energy conversion

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Reports, articles, and other documents introduced into the NASA scientific and technical information system from July 1, 1974 through September 30, 1974 are cited. Regional, national, and international energy systems; research and development on fuels and other sources of energy; energy conversion, transport, transmission, distribution, and storage, with emphasis on the use of hydrogen and solar energy are included along with methods of locating or using new energy resources. Emphasis is placed on energy for heating, lighting, and powering aircraft, surface vehicles, or other machinery.

  19. ECE 331 Electromechanical Energy Conversion Catalog Description: Energy conversion principles for electric motors. Steady-state

    E-print Network

    for electric motors. Steady-state characteristics and analysis of induction, synchronous and direct current-phase synchronous machines: wound rotor and permanent magnet. Direct-current machines. Regenerative braking machines. Credits: 4 Terms Offered: Winter Prerequisites: ENGR 202 or 202H Courses that require

  20. HEDL magnetic fusion energy programs

    Microsoft Academic Search

    D. G. Doran

    1978-01-01

    Progress is described in three HEDL programs supported by the U.S. Department of Energy's Division of Magnetic Fusion Energy. They are: (1) irradiation effects analysis, (2) mechanical performance of MFE materials, and (3) preparation and presentation of design data. Helium production cross sections for isotopes of Fe, Ni, and Cr, calculated with the HAUSER 4 code, are tabulated at 15

  1. Performance testing and economic analysis of a photovoltaic flywheel energy storage and conversion system

    SciTech Connect

    Hay, R.D.; Millner, A.R.; Jarvinen, P.O.

    1980-01-01

    A subscale prototype of a flywheel energy storage and conversion system for use with photovoltaic power systems of residential and intermediate load-center size has been designed, built and tested by MIT Lincoln Laboratory. System design, including details of such key components as magnetic bearings, motor generator, and power conditioning electronics, is described. Performance results of prototype testing are given and indicate that this system is the equal of or superior to battery-inverter systems for the same application. Results of cost and user-worth analysis show that residential systems are economically feasible in stand-alone and in some utility-interactive applications.

  2. Detection of low-energy conversion electrons and location of isomeric states

    SciTech Connect

    Kilcher; Sauvage, J.; Bourgeois, C.; Le Blanc, F.; Oms, J.; Roussiere, B.; Munsch, J.; Obert, J.; Caruette, A.; Ferro, A.; and others

    1987-12-10

    The detection of conversion electrons of short-lived isotopes at ISOCELE has been extended to very low-energy: a special tape-transport system has been built which allows the slowing down of the incoming radioactive ions and the acceleration of the electrons detected on photographic film in a flat magnetic spectrograph. Results have been acquired for the decay of mercury with A = 185, 186, 187, 189, 191, and of platinum with A = 184, and 186. As examples the location of isomeric states deduced from our measurements are given to illustrate the power of high-resolution electron detection.

  3. Compact magnetic energy storage module

    DOEpatents

    Prueitt, M.L.

    1994-12-20

    A superconducting compact magnetic energy storage module in which a plurality of superconducting toroids, each having a toroidally wound superconducting winding inside a poloidally wound superconducting winding, are stacked so that the flow of electricity in each toroidally wound superconducting winding is in a direction opposite from the direction of electrical flow in other contiguous superconducting toroids. This allows for minimal magnetic pollution outside of the module. 4 figures.

  4. Kinetic simulation of the O-X conversion process in dense magnetized plasmas

    SciTech Connect

    Ali Asgarian, M. [Physics Department, Isfahan University of Technology, Isfahan (Iran, Islamic Republic of) [Physics Department, Isfahan University of Technology, Isfahan (Iran, Islamic Republic of); Department of Electrical and Computer Engineering, Michigan State University, Michigan 48824-1226 (United States); Verboncoeur, J. P. [Department of Electrical and Computer Engineering, Michigan State University, Michigan 48824-1226 (United States)] [Department of Electrical and Computer Engineering, Michigan State University, Michigan 48824-1226 (United States); Parvazian, A. [Physics Department, Isfahan University of Technology, Isfahan (Iran, Islamic Republic of)] [Physics Department, Isfahan University of Technology, Isfahan (Iran, Islamic Republic of); Trines, R. [STFC Rutherford Appleton Laboratory, Didcot (United Kingdom)] [STFC Rutherford Appleton Laboratory, Didcot (United Kingdom)

    2013-10-15

    One scheme for heating a dense magnetized plasma core, such as in a tokamak, involves launching an ordinary (O) electromagnetic wave at the low density edge. It is converted to a reflected extraordinary (X) electromagnetic wave under certain conditions, and then transformed into an electron Bernstein wave able to reach high density regions inaccessible to most other waves. The O-X mode conversion is important in heating and diagnostic processes in different devices such as tokamaks, stellarators, and some types of pinches. The goal of this study has been to demonstrate that the kinetic particle-in-cell (PIC) scheme is suitable for modeling the O-X conversion process as the first step toward a more complete simulation of O-X-B heating. The O-X process is considered and simulated with a kinetic particle model for parameters of the TJ-II stellarator using the PIC code, XOOPIC. This code is able to model the non-monotonic density and the magnetic profile of the TJ-II stellarator. It can also statistically represent the self-consistent distribution function of the plasma, which has not been possible in previous fluid models. By considering the electric and magnetic components of launched and reflected waves, the O-mode and X-mode waves can be detected, and the O-X conversion can be demonstrated. In this work, the optimum angle for conversion efficiency, as predicted by the previous theory and experimentally confirmed, is used. Via considering the power of the launched O-mode wave and the converted X-mode wave, the efficiency of 63% for O-X conversion for the optimum theoretical launch angle of 47{sup ?} is obtained, which is in good agreement with efficiencies computed via full-wave simulations.

  5. Synergistic Energy Conversion Processes Using Nuclear Energy and Fossil Fuels

    Microsoft Academic Search

    Masao Hori

    2008-01-01

    This paper reviews the methods of producing energy carriers, such as electricity, hydrocarbons and hydrogen, by utilizing both nuclear energy and fossil fuels synergistically. There are many possibilities of new, innovative, synergistic processes, which combine chemical and nuclear systems for efficient, clean and economical production of energy carriers. Besides the individual processes by each energy to produce the energy carriers,

  6. Efficient computerized model for dynamic analysis of energy conversion systems

    NASA Astrophysics Data System (ADS)

    Hughes, R. D.; Lansing, F. L.; Khan, I. R.

    1983-02-01

    In searching for the optimum parameters that minimize the total life cycle cost of an energy conversion system, various combinations of components are examined and the resulting system performance and associated economics are studied. The systems performance and economics simulation computer program (SPECS) was developed to fill this need. The program simulates the fluid flow, thermal, and electrical characteristics of a system of components on a quasi-steady state basis for a variety of energy conversion systems. A unique approach is used in which the set of characteristic equations is solved by the Newton-Raphson technique. This approach eliminates the tedious iterative loops which are found in comparable programs such as TRNSYS or SOLTES-1. Several efficient features were also incorporated such as the centralized control and energy management scheme, and analogous treatment of energy flow in electrical and mechanical components, and the modeling of components of similar fundamental characteristics using generic subroutines. Initial tests indicate that this model can be used effectively with a relatively small number of time steps and low computer cost.

  7. Efficient computerized model for dynamic analysis of energy conversion systems

    NASA Technical Reports Server (NTRS)

    Hughes, R. D.; Lansing, F. L.; Khan, I. R.

    1983-01-01

    In searching for the optimum parameters that minimize the total life cycle cost of an energy conversion system, various combinations of components are examined and the resulting system performance and associated economics are studied. The systems performance and economics simulation computer program (SPECS) was developed to fill this need. The program simulates the fluid flow, thermal, and electrical characteristics of a system of components on a quasi-steady state basis for a variety of energy conversion systems. A unique approach is used in which the set of characteristic equations is solved by the Newton-Raphson technique. This approach eliminates the tedious iterative loops which are found in comparable programs such as TRNSYS or SOLTES-1. Several efficient features were also incorporated such as the centralized control and energy management scheme, and analogous treatment of energy flow in electrical and mechanical components, and the modeling of components of similar fundamental characteristics using generic subroutines. Initial tests indicate that this model can be used effectively with a relatively small number of time steps and low computer cost.

  8. Magnetic-field-induced alignment-to-orientation conversion in sodium

    Microsoft Academic Search

    X. L. Han; G. W. Schinn

    1991-01-01

    We report a detailed investigation of excited-state alignment-to-orientation conversion in the presence of an external magnetic field. This counterintuitive phenomenon occurs under intermediate-coupling conditions. A weak, linearly polarized, cw laser beam was used to excite and align the Na 3P3\\/2 state in an atomic beam along the z direction. The degree of circular polarization of the resulting fluorescence was detected

  9. Energy Conversion Efficiency of Nanofluidic Batteries: Hydrodynamic Slip and Access Resistance

    E-print Network

    Chang, Hsueh-Chia

    and concentration polarization) on the energy conversion efficiency of pressure-driven electrolyte flow throughEnergy Conversion Efficiency of Nanofluidic Batteries: Hydrodynamic Slip and Access Resistance Yu analytical estimates for the realistic parameters and suggests an upper bound of 50% conversion efficiency

  10. Surface conversion techniques for low energy neutral atom imagers

    NASA Technical Reports Server (NTRS)

    Quinn, J. M.

    1995-01-01

    This investigation has focused on development of key technology elements for low energy neutral atom imaging. More specifically, we have investigated the conversion of low energy neutral atoms to negatively charged ions upon reflection from specially prepared surfaces. This 'surface conversion' technique appears to offer a unique capability of detecting, and thus imaging, neutral atoms at energies of 0.01 - 1 keV with high enough efficiencies to make practical its application to low energy neutral atom imaging in space. Such imaging offers the opportunity to obtain the first instantaneous global maps of macroscopic plasma features and their temporal variation. Through previous in situ plasma measurements, we have a statistical picture of large scale morphology and local measurements of dynamic processes. However, with in situ techniques it is impossible to characterize or understand many of the global plasma transport and energization processes. A series of global plasma images would greatly advance our understanding of these processes and would provide the context for interpreting previous and future in situ measurements. Fast neutral atoms, created from ions that are neutralized in collisions with exospheric neutrals, offer the means for remotely imaging plasma populations. Energy and mass analysis of these neutrals provides critical information about the source plasma distribution. The flux of neutral atoms available for imaging depends upon a convolution of the ambient plasma distribution with the charge exchange cross section for the background neutral population. Some of the highest signals are at relatively low energies (well below 1 keV). This energy range also includes some of the most important plasma populations to be imaged, for example the base of the cleft ion fountain.

  11. Renewable energy from the sea - organic Rankine Cycle using ocean thermal energy conversion

    Microsoft Academic Search

    S. K. Wang; T. C. Hung

    2010-01-01

    Rankine cycles using refrigerant- and benzene-series fluids as working fluids in converting low-grade energy from renewable energy resources such as solar energy and ocean thermal energy were investigated in this study. The main purpose is to verify the feasibility of utilizing ocean energy (i.e., ocean thermal energy conversion, OTEC) which can also be combined with solar energy in an organic

  12. Renewable energy from corn residues by thermochemical conversion

    NASA Astrophysics Data System (ADS)

    Yu, Fei

    Declining fossil oil reserve, skyrocket price, unsecured supplies, and environment pollution are among the many energy problems we are facing today. It is our conviction that renewable energy is a solution to these problems. The long term goal of the proposed research is to develop commercially practical technologies to produce energy from renewable resources. The overall objective of my research is to study and develop thermochemical processes for converting bulky and low-energy-density biomass materials into bio-fuels and value-added bio-products. The rationale for the proposed research is that, once such processes are developed, processing facility can be set up on or near biomass product sites, reducing the costs associated with transport of bulky biomass which is a key technical barrier to biomass conversion. In my preliminary research, several conversion technologies including atmospheric pressure liquefaction, high pressure liquefaction, and microwave pyrolysis have been evaluated. Our data indicated that microwave pyrolysis had the potential to become a simple and economically viable biomass conversion technology. Microwave pyrolysis is an innovative process that provides efficient and uniform heating, and are robust to type, size and uniformity of feedstock and therefore suitable for almost any waste materials without needing to reduce the particle size. The proposed thesis focused on in-depth investigations of microwave pyrolysis of corn residues. My first specific aim was to examine the effects of processing parameters on product yields. The second specific research aim was to characterize the products (gases, bio-oils, and solid residues), which was critical to process optimization and product developments. Other research tasks included conducting kinetic modeling and preliminary mass and energy balance. This study demonstrated that microwave pyrolysis could be optimized to produce high value syngas, liquid fuels and pyrolytic carbons, and had a great potential to become a commercial process according to the mass and energy balance. One-step global model and two-step consecutive-reaction kinetic model offered a clue to the key mechanistic steps in the overall pyrolysis of corn residues. These results should have a positive impact on advancing renewable energy technologies and establishing the University's leadership status in the area of renewable energy development.

  13. Method and apparatus for testing electrochemical energy conversion devices

    NASA Technical Reports Server (NTRS)

    Cisar, Alan J. (Inventor); Murphy, Oliver J. (Inventor)

    1996-01-01

    A system for testing electrochemical energy conversion and storage devices includes means for sensing the current from the storage device and varying the load across the storage device in response to the current sensed. The system is equally adaptable to batteries and fuel cells. Means is also provided to sense system parameters from a plurality of locations within the system. Certain parameters are then stored in digital form for archive purposes and certain other parameters are used to develop control signals in a host processor.

  14. Analysis of dynamic effects in solar thermal energy conversion systems

    NASA Technical Reports Server (NTRS)

    Hamilton, C. L.

    1978-01-01

    The paper examines a study the purpose of which is to assess the performance of solar thermal power systems insofar as it depends on the dynamic character of system components and the solar radiation which drives them. Using a dynamic model, the daily operation of two conceptual solar conversion systems was simulated under varying operating strategies and several different time-dependent radiation intensity functions. These curves ranged from smoothly varying input of several magnitudes to input of constant total energy whose intensity oscillated with periods from 1/4 hour to 6 hours.

  15. Advanced solar energy conversion. [solar pumped gas lasers

    NASA Technical Reports Server (NTRS)

    Lee, J. H.

    1981-01-01

    An atomic iodine laser, a candidate for the direct solar pumped lasers, was successfully excited with a 4 kW beam from a xenon arc solar simulator, thus proving the feasibility of the concept. The experimental set up and the laser output as functions of operating conditions are presented. The preliminary results of the iodine laser amplifier pumped with the HCP array to which a Q switch for giant pulse production was coupled are included. Two invention disclosures - a laser driven magnetohydrodynamic generator for conversion of laser energy to electricity and solar pumped gas lasers - are also included.

  16. A novel thin-film electrochemical device for energy conversion

    NASA Astrophysics Data System (ADS)

    Dyer, C. K.

    1990-02-01

    The observation of gas to electrical energy conversion processes occurring within very thin films is reported. Voltages as large as 1 volt are observed between platinum electrodes separated by thin gas-permeable, ionically conducting membranes when one electrode is exposed to, for example, a mixture of air and hydrogen at room temperature. These observations contrast with the behavior of conventional fuel cells, which cannot operate if the gases are mixed, and could radically simplify fuel-cell design. On the basis of these results, a simple manufacturing process is suggested by which small fuel cells could be made available at low cost.

  17. Low cost composite materials for wind energy conversion systems

    NASA Astrophysics Data System (ADS)

    Weingart, O.

    1980-06-01

    A winding process utilizing a low-cost E-glass fabric called transverse-filament tape for low-cost production of wind turbine generators (WTG) is described. The process can be carried out continuously at high speed to produce large one-piece parts with tapered wall thicknesses on a tapered mandrel. It is being used to manufacture blades for the NASA/DOE 200-ft-diameter MOD-1 WTG and Rockwell/DOE 40-kW small wind energy conversion system (SWECS).

  18. Nanostructured Solar Irradiation Control Materials for Solar Energy Conversion

    NASA Technical Reports Server (NTRS)

    Kang, Jinho; Marshall, I. A.; Torrico, M. N.; Taylor, C. R.; Ely, Jeffry; Henderson, Angel Z.; Kim, J.-W.; Sauti, G.; Gibbons, L. J.; Park, C.; Lowther, S. E.; Lillehei, P. T.; Bryant, R. G.

    2012-01-01

    Tailoring the solar absorptivity (alpha(sub s)) and thermal emissivity (epsilon(sub T)) of materials constitutes an innovative approach to solar energy control and energy conversion. Numerous ceramic and metallic materials are currently available for solar absorbance/thermal emittance control. However, conventional metal oxides and dielectric/metal/dielectric multi-coatings have limited utility due to residual shear stresses resulting from the different coefficient of thermal expansion of the layered materials. This research presents an alternate approach based on nanoparticle-filled polymers to afford mechanically durable solar-absorptive and thermally-emissive polymer nanocomposites. The alpha(sub s) and epsilon(sub T) were measured with various nano inclusions, such as carbon nanophase particles (CNPs), at different concentrations. Research has shown that adding only 5 wt% CNPs increased the alpha(sub s) and epsilon(sub T) by a factor of about 47 and 2, respectively, compared to the pristine polymer. The effect of solar irradiation control of the nanocomposite on solar energy conversion was studied. The solar irradiation control coatings increased the power generation of solar thermoelectric cells by more than 380% compared to that of a control power cell without solar irradiation control coatings.

  19. Nanostructured solar irradiation control materials for solar energy conversion

    NASA Astrophysics Data System (ADS)

    Kang, Jin Ho; Marshall, Iseley A.; Torrico, Mattew N.; Taylor, Chase R.; Ely, Jeffry; Henderson, Angel; Sauti, Godfrey; Gibbons, Luke J.; Kim, Jae-Woo; Park, Cheol; Lowther, Sharon E.; Lillehei, Peter T.; Bryant, Robert G.

    2012-10-01

    Tailoring the solar absorptivity (?s) and thermal emissivity (?T) of materials constitutes an innovative approach to solar energy control and energy conversion. Numerous ceramic and metallic materials are currently available for solar absorbance/thermal emittance control. However, conventional metal oxides and dielectric/metal/dielectric multi-coatings have limited utility due to residual shear stresses resulting from the different coefficient of thermal expansion of the layered materials. This research presents an alternate approach based on nanoparticle-filled polymers to afford mechanically durable solar-absorptive and thermally-emissive polymer nanocomposites. The ?s and ?T were measured with various nano inclusions, such as carbon nanophase particles (CNPs), at different concentrations. Research has shown that adding only 5 wt% CNPs increased the ?s and ?T by a factor of about 47 and 2, respectively, compared to the pristine polymer. The effect of solar irradiation control of the nanocomposite on solar energy conversion was studied. The solar irradiation control coatings increased the power generation of solar thermoelectric cells by more than 380% compared to that of a control power cell without solar irradiation control coatings.

  20. PRELIMINARY ENVIRONMENTAL ASSESSMENT OF ENERGY CONVERSION PROCESSES FOR AGRICULTURAL AND FOREST PRODUCT RESIDUES. VOLUME 1

    EPA Science Inventory

    A preliminary assessment was made of the environmental impacts of several types of conversion processes for producing energy or fuels from agricultural and forestry residues. Fifteen examples were selected to represent various combinations of agricultural residues and conversion ...

  1. Quantum coherence in photosynthesis for efficient solar-energy conversion

    NASA Astrophysics Data System (ADS)

    Romero, Elisabet; Augulis, Ramunas; Novoderezhkin, Vladimir I.; Ferretti, Marco; Thieme, Jos; Zigmantas, Donatas; van Grondelle, Rienk

    2014-09-01

    The crucial step in the conversion of solar to chemical energy in photosynthesis takes place in the reaction centre, where the absorbed excitation energy is converted into a stable charge-separated state by ultrafast electron transfer events. However, the fundamental mechanism responsible for the near-unity quantum efficiency of this process is unknown. Here we elucidate the role of coherence in determining the efficiency of charge separation in the plant photosystem II reaction centre by comprehensively combining experiment (two-dimensional electronic spectroscopy) and theory (Redfield theory). We reveal the presence of electronic coherence between excitons as well as between exciton and charge-transfer states that we argue to be maintained by vibrational modes. Furthermore, we present evidence for the strong correlation between the degree of electronic coherence and efficient and ultrafast charge separation. We propose that this coherent mechanism will inspire the development of new energy technologies.

  2. Energy and data conversion circuits for low power sensory systems

    NASA Astrophysics Data System (ADS)

    Ghosh, Suvradip

    This dissertation focuses on the problem of increasing the lifetime of wireless sensors. This problem is addressed from two different angles: energy harvesting and data compression. Energy harvesting enables a sensor to extract energy from its environment and use it to power itself or recharge its batteries. Data compression, on the other hand, allows a sensor to save energy by reducing the radio transmission bandwidth. This dissertation proposes a fractal-based photodiode fabricated on standard CMOS process as an energy harvesting device with increased efficiency. Experiments show that, the fractal based photodiodes are 6% more efficient compared to the conventional square shaped photodiode. The fractal shape photodiode has more perimeter-to-area ratio which increases the lateral response, improving its efficiency. With increased efficiency, more current is generated but the open-circuit voltage still remains low (0.3V--0.45V depending on illumination condition). These voltages have to be boosted up to higher values if they are going to be used to power up any sensory circuit or recharge a battery. We propose a switched-inductor DC-DC converter to boost the low voltage of the photodiodes to higher voltages. The proposed circuit uses two on-chip switches and two off-chip Components: an inductor and a capacitor. Experiments show a voltage up to 2.81V can be generated from a single photodiode of 1mm2 area. The voltage booster circuit achieved a conversion efficiency of 59%. Data compression was also explored in an effort to reduce energy consumption during radio transmission. An analog-to-digital converter (ADC), which can jointly perform the tasks of digital conversion and entropy encoding, has also been proposed in this dissertation. The joint data conversion/compression help savings in area and power resources, making it suitable for on-sensor compression. The proposed converter combines a cyclic converter architecture and Golomb-Rice entropy encoder. The converter hardware design is based on current-mode circuits and it was fabricated on a 0.5 mum CMOS process and tested. Experiment results show a lossless compression ratio of 1.52 and a near-lossless compression of 5.2 can be achieved for 32 x 32 pixel image.

  3. High Temperature Fusion Reactor Cooling Using Brayton Cycle Based Partial Energy Conversion

    NASA Astrophysics Data System (ADS)

    Juhasz, Albert J.; Sawicki, Jerzy T.

    2004-02-01

    For some future space power systems using high temperature nuclear heat sources most of the output energy will be used in other than electrical form, and only a fraction of the total thermal energy generated will need to be converted to electrical work. The paper describes the conceptual design of such a ``partial energy conversion'' system, consisting of a high temperature fusion reactor operating in series with a high temperature radiator and in parallel with dual closed cycle gas turbine (CCGT) power systems, also referred to as closed Brayton cycle (CBC) systems, which are supplied with a fraction of the reactor thermal energy for conversion to electric power. Most of the fusion reactor's output is in the form of charged plasma which is expanded through a magnetic nozzle of the interplanetary propulsion system. Reactor heat energy is ducted to the high temperature series radiator utilizing the electric power generated to drive a helium gas circulation fan. In addition to discussing the thermodynamic aspects of the system design the authors include a brief overview of the gas turbine and fan rotor-dynamics and proposed bearing support technology along with performance characteristics of the three phase AC electric power generator and fan drive motor.

  4. Investigation on energy conversion technology using biochemical reaction elements, 2

    NASA Astrophysics Data System (ADS)

    1994-03-01

    For measures taken for resource/energy and environmental issues, a study is made on utilization of microbial biochemical reaction. As a reaction system using chemical energy, cited is production of petroleum substitution substances and food/feed by CO2 fixation using hydrogen energy and hydrogen bacteria. As to photo energy utilization, regarded as promising are CO2 fixation using photo energy and microalgae, and production of hydrogen and useful carbon compound using photosynthetic organisms. As living organism/electric energy interconversion, cited is the culture of chemoautotrophic bacteria which fix CO2 using electric energy. For enhancing its conversion efficiency, it is important to develop a technology of gene manipulation of the bacteria and a system to use functional biochemical elements adaptable to the electrode reaction. With regard to utilization of the microorganism metabolic function, the paper presents emission of soluble nitrogen in the hydrosphere into the atmosphere using denitrifying bacteria, removal of phosphorus, reduction in environmental pollution caused by heavy metal dilute solutions, and recovery as resources, etc.

  5. Proceedings of the Chornobyl phytoremediation and biomass energy conversion workshop

    SciTech Connect

    Hartley, J. [Pacific Northwest National Lab., Richland, WA (United States)] [Pacific Northwest National Lab., Richland, WA (United States); Tokarevsky, V. [State Co. for Treatment and Disposal of Mixed Hazardous Waste (Ukraine)] [State Co. for Treatment and Disposal of Mixed Hazardous Waste (Ukraine)

    1998-06-01

    Many concepts, systems, technical approaches, technologies, ideas, agreements, and disagreements were vigorously discussed during the course of the 2-day workshop. The workshop was successful in generating intensive discussions on the merits of the proposed concept that includes removal of radionuclides by plants and trees (phytoremediation) to clean up soil in the Chornobyl Exclusion Zone (CEZ), use of the resultant biomass (plants and trees) to generate electrical power, and incorporation of ash in concrete casks to be used as storage containers in a licensed repository for low-level waste. Twelve years after the Chornobyl Nuclear Power Plant (ChNPP) Unit 4 accident, which occurred on April 26, 1986, the primary 4radioactive contamination of concern is from radioactive cesium ({sup 137}Cs) and strontium ({sup 90}Sr). The {sup 137}Cs and {sup 90}Sr were widely distributed throughout the CEZ. The attendees from Ukraine, Russia, Belarus, Denmark and the US provided information, discussed and debated the following issues considerably: distribution and characteristics of radionuclides in CEZ; efficacy of using trees and plants to extract radioactive cesium (Cs) and strontium (Sr) from contaminated soil; selection of energy conversion systems and technologies; necessary infrastructure for biomass harvesting, handling, transportation, and energy conversion; radioactive ash and emission management; occupational health and safety concerns for the personnel involved in this work; and economics. The attendees concluded that the overall concept has technical and possibly economic merits. However, many issues (technical, economic, risk) remain to be resolved before a viable commercial-scale implementation could take place.

  6. ECUT (Energy Conversion and Utilization Technologies) program: Biocatalysis Project

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Fiscal year 1987 research activities and accomplishments for the Biocatalysis Project of the U.S. Department of Energy, Energy Conversion and Utilization Technologies (ECUT) Division are presented. The project's technical activities were organized into three work elements. The Molecular Modeling and Applied Genetics work element includes modeling and simulation studies to verify a dynamic model of the enzyme carboxypeptidase; plasmid stabilization by chromosomal integration; growth and stability characteristics of plasmid-containing cells; and determination of optional production parameters for hyper-production of polyphenol oxidase. The Bioprocess Engineering work element supports efforts in novel bioreactor concepts that are likely to lead to substantially higher levels of reactor productivity, product yields, and lower separation energetics. The Bioprocess Design and Assessment work element attempts to develop procedures (via user-friendly computer software) for assessing the economics and energetics of a given biocatalyst process.

  7. Controlled cellular energy conversion in brown adipose tissue thermogenesis

    NASA Technical Reports Server (NTRS)

    Horowitz, J. M.; Plant, R. E.

    1978-01-01

    Brown adipose tissue serves as a model system for nonshivering thermogenesis (NST) since a) it has as a primary physiological function the conversion of chemical energy to heat; and b) preliminary data from other tissues involved in NST (e.g., muscle) indicate that parallel mechanisms may be involved. Now that biochemical pathways have been proposed for brown fat thermogenesis, cellular models consistent with a thermodynamic representation can be formulated. Stated concisely, the thermogenic mechanism in a brown fat cell can be considered as an energy converter involving a sequence of cellular events controlled by signals over the autonomic nervous system. A thermodynamic description for NST is developed in terms of a nonisothermal system under steady-state conditions using network thermodynamics. Pathways simulated include mitochondrial ATP synthesis, a Na+/K+ membrane pump, and ionic diffusion through the adipocyte membrane.

  8. Silicon nanowires for biosensing, energy storage, and conversion.

    PubMed

    Wang, Yanli; Wang, Tianyu; Da, Peimei; Xu, Ming; Wu, Hao; Zheng, Gengfeng

    2013-10-01

    Semiconducting silicon nanowires (SiNWs) represent one of the most interesting research directions in nanoscience and nanotechnology, with capabilities of realizing structural and functional complexity through rational design and synthesis. The exquisite control of chemical composition, structure, morphology, doping, and assembly of SiNWs, in both individual and array format, as well as incorporation with other materials, offers a nanoscale building block with unique electronic, optoelectronic, and catalytic properties, thus allowing for a variety of exciting opportunities in the fields of life sciences and renewable energy. This review provides a brief summary of SiNW research in the past decade, from the SiNW synthesis by both the top-down approaches and the bottom-up approaches, to several important biological and energy applications including biomolecule sensing, interfacing with cells and tissues, lithium-ion batteries, solar cells, and photoelectrochemical conversion. PMID:23828226

  9. Segregated tandem filter for enhanced conversion efficiency in a thermophotovoltaic energy conversion system

    DOEpatents

    Brown, Edward J. (Clifton Park, NY); Baldasaro, Paul F. (Clifton Park, NY); Dziendziel, Randolph J. (Middlegrove, NY)

    1997-01-01

    A filter system to transmit short wavelength radiation and reflect long wavelength radiation for a thermophotovoltaic energy conversion cell comprises an optically transparent substrate segregation layer with at least one coherent wavelength in optical thickness; a dielectric interference filter deposited on one side of the substrate segregation layer, the interference filter being disposed toward the source of radiation, the interference filter including a plurality of alternating layers of high and low optical index materials adapted to change from transmitting to reflecting at a nominal wavelength .lambda..sub.IF approximately equal to the bandgap wavelength .lambda..sub.g of the thermophotovoltaic cell, the interference filter being adapted to transmit incident radiation from about 0.5.lambda..sub.IF to .lambda..sub.IF and reflect from .lambda..sub.IF to about 2.lambda..sub.IF ; and a high mobility plasma filter deposited on the opposite side of the substrate segregation layer, the plasma filter being adapted to start to become reflecting at a wavelength of about 1.5.lambda..sub.IF.

  10. Segregated tandem filter for enhanced conversion efficiency in a thermophotovoltaic energy conversion system

    DOEpatents

    Brown, E.J.; Baldasaro, P.F.; Dziendziel, R.J.

    1997-12-23

    A filter system to transmit short wavelength radiation and reflect long wavelength radiation for a thermophotovoltaic energy conversion cell comprises an optically transparent substrate segregation layer with at least one coherent wavelength in optical thickness; a dielectric interference filter deposited on one side of the substrate segregation layer, the interference filter being disposed toward the source of radiation, the interference filter including a plurality of alternating layers of high and low optical index materials adapted to change from transmitting to reflecting at a nominal wavelength {lambda}{sub IF} approximately equal to the bandgap wavelength {lambda}{sub g} of the thermophotovoltaic cell, the interference filter being adapted to transmit incident radiation from about 0.5{lambda}{sub IF} to {lambda}{sub IF} and reflect from {lambda}{sub IF} to about 2{lambda}{sub IF}; and a high mobility plasma filter deposited on the opposite side of the substrate segregation layer, the plasma filter being adapted to start to become reflecting at a wavelength of about 1.5{lambda}{sub IF}. 10 figs.

  11. The Status of Thermophotovoltaic Energy Conversion Technology at Lockheed Martin Corporation

    Microsoft Academic Search

    EJ Brown; PF Baldasaro; SR Burger; LR Danielson; DM DePoy; JM Dolatowski; PM Fourspring; GJ Nichols; WF Topper; TD Rahmlow

    2004-01-01

    In a thermophotovoltaic (TPV) energy conversion system, a heated surface radiates in the mid-infrared range onto photocells which are sensitive at these energies. Part of the absorbed energy is converted into electric output. Conversion efficiency is maximized by reducing the absorption of non-convertible energy with some form of spectral control. In a TPV system, many technology options exist. Our development

  12. The Status of Thermophotovoltaic Energy Conversion Technology at Lockheed Martin Corp

    Microsoft Academic Search

    E. J. Brown; P. F. Baldasaro; S. R. Burger; L. R. Danielson; D. M. DePoy; G. J. Nichols; W. F. Topper; T. D. Rahmlow

    2003-01-01

    In a thermophotovoltaic (TPV) energy conversion system, a heated surface radiates in the mid-infrared range onto photodiodes which are sensitive at these energies. Part of the absorbed energy is converted into electric output. Conversion efficiency is maximized by reducing the absorption of non-convertible energy with some form of spectral control. In a TPV system, many technology options exist. The development

  13. Wave Energy Conversion Overview and it's Renewable Energy Potential for the Oil and Gas Industry

    E-print Network

    Pastor, J.; Liu, Y.; Dou, Y.

    2014-01-01

    . Keywords: hydrokinetic energy; wave energy; ocean energy; Gulf of Mexico; wave energy conversion INTRODUCTION Ocean energy comes in a variety of forms such as marine currents, tidal currents, geothermal vents, and waves. All are concentrated... currents and waves. Some research has been conducted on constructing a heat cycle based on geothermal vents, but this work has led to the conclusion that geothermal vents are not commercially viable [2]. On the other hand, ocean current and wave...

  14. Refractory materials for high-temperature thermoelectric energy conversion

    NASA Technical Reports Server (NTRS)

    Wood, C.; Emin, D.

    1984-01-01

    Theoretical work of two decades ago adequately explained the transport behavior and effectively guided the development of thermoelectric materials of high conversion efficiencies of conventional semiconductors (e.g., SiGe alloys). The more significant contributions involved the estimaiation of optimum doping concentrations, the reduction of thermal conductivity by solid solution doping and the development of a variety of materials with ZT approx. 1 in the temperature range 300 K to 1200 K. ZT approx. 1 is not a theoretical limitation although, experimentally, values in excess of one were not achieved. Work has continued with emphasis on higher temperature energy conversion. A number of promising materials have been discovered in which it appears that ZT 1 is realizable. These materials are divided into two classes: (1) the rare-earth chalcogenides which behave as itinerant highly-degenerate n-type semiconductors at room-temperature, and (2) the boron-rich borides, which exhibit p-type small-polaronic hopping conductivity.

  15. Relation of the second law of thermodynamics to the power conversion of energy fluctuations

    Microsoft Academic Search

    Joseph C. Yater

    1979-01-01

    The relation of the second law of thermodynamics to the power conversion of fluctuation energy is analyzed using the master equation of the model for the conversion circuit. The performance equation for independent particles shows that the power-conversion performance is given by the second law both for classical and quantum-effect diodes. The relation of the second law to power-conversion models

  16. Direct energy conversion bottoming cycles for solid oxide fuel cells

    SciTech Connect

    Paramonov, D.V.; Carelli, M.D.

    1998-07-01

    Besides high conversion efficiency, advantages of Solid Oxide Fuel Cell (SOFC) include ability of low pressure operation, absence of moving parts and resulting inherently low maintenance requirements, modularity, long lifetime and unattended operation. A further increase in the conversion efficiency, without compromising the advantages inherent with static devices, can be achieved by employing a direct energy conversion bottoming cycle. The biggest challenges in the integration of direct energy conversion devices with SOFC are: (a) the need to preheat the SOFC feed air while maximizing the bottoming cycle power, and (b) limited temperature of the SOFC exhaust. These restrictions limit the choice to the Alkali Metal Thermal to Electric Conversion (AMTEC) and Thermoelectric (TE) technologies while eliminating thermionics and thermophotovoltaics. In addition to the aforementioned advantages, the SOFC-AMTEC and SOFC-TE cycles are attractive for certain applications such as cogeneration and power supplies for remote locations where the use of higher efficiency dynamic bottoming cycles might be undesirable due to maintenance and noise restrictions. A preliminary feasibility assessment of AMTEC and TE bottoming of SOFC power systems has been performed. Five SOFC bottoming cycle concepts were considered. They include: TE bottoming with cogeneration capability, TE bottoming with additional heat recovery, TE bottoming with uncoupled TE converter and air preheater, AMTEC bottoming, and Cascaded AMTEC-TE bottoming. The cascaded AMTEC-TE bottoming cycle increases the overall cycle efficiency by 4.7 percentage points. TE bottoming cycle with additional heat recovery adds 3.8 percentage points, and the other concepts are between 3 and 3.5 percentage points. The results are also compared with results of similar studies reported in literature. The AMTEC-TE cascade has the largest potential, however, development of both AMTEC and TE components would be required. The second best option from the efficiency point of view is the TE bottoming with additional heat recovery which would require development of only the TE component. Despite that fact that AMTEC is generally perceived as more efficient than thermoelectrics, efficiencies of the considered AMTEC and TE bottoming cycles are almost equal. The reason is that the somewhat more efficient AMTEC requires relatively high hot side temperature ({gt}850--900 K) and, at the same time, air has to be preheated to 973 K. (This is equally true for a high efficiency TE converter operating at the highest hot side to cold side temperature difference possible). As a result, only a small fraction ({lt}30 %) of the total heat available is directed to the bottoming cycle where it is converted with relatively high efficiency. When a TE converter operating in a wider hot side temperature range, but at a smaller hot side--cold side temperature difference is employed, its lower efficiency is offset by its larger thermal power and the overall bottoming cycle efficiency changes insignificantly.

  17. Energy transfer processes in solar energy conversion. Final report

    SciTech Connect

    Fayer, M.D.

    1984-01-01

    The following were studied experimentally and/or theoretically: dynamics of energy transport and trapping in two-component systems (using rhodamine 6G and malachite green as traps), electronic excited state transport among molecules randomly distributed in a finite volume, electronic excitation transport in polymer systems, and excitation transport in synthetic Zn-chlorophyllide substituted hemoglobin. (DLC)

  18. Monolithic Interconnected Modules (MIMs) for Thermophotovoltaic Energy Conversion

    NASA Technical Reports Server (NTRS)

    Wilt, David; Wehrer, Rebecca; Palmisiano, Marc; Wanlass, Mark; Murray, Christopher

    2003-01-01

    Monolithic Interconnected Modules (MIM) are under development for thermophotovoltaic (TPV) energy conversion applications. MIM devices are typified by series-interconnected photovoltaic cells on a common, semi-insulating substrate and generally include rear-surface infrared (IR) reflectors. The MIM architecture is being implemented in InGaAsSb materials without semi-insulating substrates through the development of alternative isolation methodologies. Motivations for developing the MIM structure include: reduced resistive losses, higher output power density than for systems utilizing front surface spectral control, improved thermal coupling and ultimately higher system efficiency. Numerous design and material changes have been investigated since the introduction of the MIM concept in 1994. These developments as well as the current design strategies are addressed.

  19. Siting handbook for small wind energy conversion systems

    SciTech Connect

    Wegley, H.L.; Ramsdell, J.V.; Orgill, M.M.; Drake, R.L.

    1980-03-01

    This handbook was written to serve as a siting guide for individuals wishing to install small wind energy conversion systems (WECS); that is, machines having a rated capacity of less than 100 kilowatts. It incorporates half a century of siting experience gained by WECS owners and manufacturers, as well as recently developed siting techniques. The user needs no technical background in meteorology or engineering to understand and apply the siting principles discussed; he needs only a knowledge of basic arithmetic and the ability to understand simple graphs and tables. By properly using the siting techniques, an owner can select a site that will yield the most power at the least installation cost, the least maintenance cost, and the least risk of damage or accidental injury.

  20. 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.

  1. Photochemical energy conversion by membrane-bound photoredox systems

    SciTech Connect

    Tollin, G.

    1992-03-01

    Most of our effort during the past grant period has been directed towards investigating electron transfer processes involving redox proteins at lipid bilayer/aqueous interfaces. This theme, as was noted in our previous three year renewal proposal, is consistent with our goal of developing biomimetic solar energy conversion systems which utilize the unique properties of biological electron transfer molecules. Thus, small redox proteins such as cytochrome c, plastocyanin and ferredoxin function is biological photosynthesis as mediators of electron flow between the photochemical systems localized in the membrane, and more complex soluble or membrane-bound redox proteins which are designed to carry out specific biological tasks such as transbilayer proton gradient formation, dinitrogen fixation, ATP synthesis, dihydrogen synthesis, generation of strong reductants, etc. In these studies, we have utilized two principal experimental techniques, laser flash photolysis and cyclic voltammetry, both of which permit direct measurements of electron transfer processes.

  2. Wave Energy Conversion Overview and it's Renewable Energy Potential for the Oil and Gas Industry 

    E-print Network

    Pastor, J.; Liu, Y.; Dou, Y.

    2014-01-01

    Ocean energy conversion has been of interest for many years. Recent developments such as concern over global warming have renewed interest in the topic. Part II provides an overview of the energy density found in ocean waves and how it is calculated...

  3. Optical materials technology for energy efficiency and solar energy conversion. Vol. 653

    SciTech Connect

    Not Available

    1986-01-01

    This book presents papers on optical materials technology for energy efficiency and solar energy conversion V. Topics covered include: electrochromic devices for transmissive and reflective light control; high contrast electrochromic tungsten oxide layers; transparent thermal insulation with infrared-absorbing gases; and a modified luminescent solar concentrator.

  4. Review of pyroelectric thermal energy harvesting and new MEMs based resonant energy conversion techniques

    SciTech Connect

    Hunter, Scott Robert [ORNL; Lavrik, Nickolay V [ORNL; Mostafa, Salwa [ORNL; Rajic, Slobodan [ORNL; Datskos, Panos G [ORNL

    2012-01-01

    Harvesting electrical energy from thermal energy sources using pyroelectric conversion techniques has been under investigation for over 50 years, but it has not received the attention that thermoelectric energy harvesting techniques have during this time period. This lack of interest stems from early studies which found that the energy conversion efficiencies achievable using pyroelectric materials were several times less than those potentially achievable with thermoelectrics. More recent modeling and experimental studies have shown that pyroelectric techniques can be cost competitive with thermoelectrics and, using new temperature cycling techniques, has the potential to be several times as efficient as thermoelectrics under comparable operating conditions. This paper will review the recent history in this field and describe the techniques that are being developed to increase the opportunities for pyroelectric energy harvesting. The development of a new thermal energy harvester concept, based on temperature cycled pyroelectric thermal-to-electrical energy conversion, are also outlined. The approach uses a resonantly driven, pyroelectric capacitive bimorph cantilever structure that can be used to rapidly cycle the temperature in the energy harvester. The device has been modeled using a finite element multi-physics based method, where the effect of the structure material properties and system parameters on the frequency and magnitude of temperature cycling, and the efficiency of energy recycling using the proposed structure, have been modeled. Results show that thermal contact conductance and heat source temperature differences play key roles in dominating the cantilever resonant frequency and efficiency of the energy conversion technique. This paper outlines the modeling, fabrication and testing of cantilever and pyroelectric structures and single element devices that demonstrate the potential of this technology for the development of high efficiency thermal-to-electrical energy conversion devices.

  5. A novel thermomechanical energy conversion cycle Ian M. McKinley, Felix Y. Lee, Laurent Pilon

    E-print Network

    Pilon, Laurent

    . The most widely used method to harvest mechanical energy is piezoelectric energy conversion [3]. It makes power than traditional mechanical cycles using piezoelectric materials. a r t i c l e i n f o Article: Pyroelectric materials Direct energy conversion Waste heat harvesting Ferroelectric materials Olsen cycle

  6. Economics of Ocean Thermal Energy Conversion Luis A. Vega, Ph.D.

    E-print Network

    Economics of Ocean Thermal Energy Conversion (OTEC) by Luis A. Vega, Ph.D. Published 36 #12;Published in Ocean Energy Recovery, pp 152-181, ASCE (1992) Vega1 7: Economics of Ocean Thermal Energy Conversion (OTEC) Luis A. Vega, Ph.D.1, 2 Abstract A straightforward analytical model

  7. Sustainable systems for the storage and conversion of energy are dependent on interconnected

    E-print Network

    Reisslein, Martin

    SEMTE abstract Sustainable systems for the storage and conversion of energy are dependent framework, the development of new sustainable energy technologies for applications including high systems, and sustainable energy portfolios has resulted in over 20 archival journal and conference

  8. Thermal energy conversion by coupled shape memory and piezoelectric effects

    NASA Astrophysics Data System (ADS)

    Zakharov, Dmitry; Lebedev, Gor; Cugat, Orphee; Delamare, Jerome; Viala, Bernard; Lafont, Thomas; Gimeno, Leticia; Shelyakov, Alexander

    2012-09-01

    This work gives experimental evidence of a promising method of thermal-to-electric energy conversion by coupling shape memory effect (SME) and direct piezoelectric effect (DPE) for harvesting quasi-static ambient temperature variations. Two original prototypes of thermal energy harvesters have been fabricated and tested experimentally. The first is a hybrid laminated composite consisting of TiNiCu shape memory alloy (SMA) and macro fiber composite piezoelectric. This composite comprises 0.1 cm3 of active materials and harvests 75 µJ of energy for each temperature variation of 60 °C. The second prototype is a SME/DPE ‘machine’ which uses the thermally induced linear strains of the SMA to bend a bulk PZT ceramic plate through a specially designed mechanical structure. The SME/DPE ‘machine’ with 0.2 cm3 of active material harvests 90 µJ over a temperature increase of 35 °C (60 µJ when cooling). In contrast to pyroelectric materials, such harvesters are also compatible with both small and slow temperature variations.

  9. Alkali layered compounds interfaces for energy conversion and energy storage

    NASA Technical Reports Server (NTRS)

    Papageorgopoulos, Chris A.

    1996-01-01

    During year one a new ultra-high vacuum, an Ar(+) ion sputterer, a low energy electron diffraction (LEED) system, an Auger electron spectrometer (AES), a work function measurement device with a Kelvin probe, and related accessories were used. The study found a focus in the adsorption of chalcogenides on Si and III-V compound semiconductors. In the second year, a scanning tunneling microscope was obtained along with a quadrapole mass spectrometer, power supplies, a computer, a chart recorder, etc. We started the systematic study on the adsorption of chalcogenides on the compound semiconductor surfaces. The third year saw the mounting of the scanning tunneling microscope (STM) on the existing UHV system. The investigation continued with the adsorption of Cs (alkali) on S-covered Si(100)2x1 surfaces. Then the adsorption of S on Cs-covered Si(100) surfaces was studied.

  10. Magnetic and Moessbauer characterization of iron/zeolite catalysts and syngas conversion studies

    SciTech Connect

    Oskooie-Tabrizi, M.M.

    1983-01-01

    Bifunctional catalysts containing the medium pore (0.6 nm) zeolite and Group VIII metals, such as Fe or (Fe + Co), are of considerable interest for the conversion of syngas (synthesis gas; H/sub 2/ + CO) to gasoline range (C/sub 5/ - C/sub 11/) hydrocarbons. Various synthetic zeolites used in this study consisted of acidic zeolites, such as H-ZSM-5 and H-mordenite, and a non-acidic zeolite, namely, Silicalite. This investigation was undertaken to: 1) study the effect of the nitrate and carbonyl impregnated methods on the dispersions of Fe; 2) see if the above combinations have any marked effect on the syngas conversion; and explore if there is any metal-support interaction between the Fe clusters and the varying number of acid sites in zeolites, especially with respect to the mordenites. Iron was chosen in this study for a variety of reasons, such as its technological relevance in the commercial Fischer-Tropsch synthesis and its lower cost, as compared with the cost of other transition metals. The Fe/zeolite catalysts were characterized by in-situ magnetization, and Moessbauer techniques. IR spectroscopy was also used in investigating H-mordenites. These catalysts were also tested for their Fischer-Tropsch activity, that is, for the syngas conversion to gasoline range hydrocarbons.

  11. Magnetic Resonance Studies of Energy Storage Materials

    NASA Astrophysics Data System (ADS)

    Vazquez Reina, Rafael

    In today's society there is high demand to have access to energy for portable devices in different forms. Capacitors with high performance in small package to achieve high charge/discharge rates, and batteries with their ability to store electricity and make energy mobile are part of this demand. The types of internal dielectric material strongly affect the characteristics of a capacitor, and its applications. In a battery, the choice of the electrolyte plays an important role in the Solid Electrolyte Interphase (SEI) formation, and the cathode material for high output voltage. Electron Paramagnetic Resonance (EPR) and Nuclear Magnetic Resonance (NMR) spectroscopy are research techniques that exploit the magnetic properties of the electron and certain atomic nuclei to determine physical and chemical properties of the atoms or molecules in which they are contained. Both EPR and NMR spectroscopy technique can yield meaningful structural and dynamic information. Three different projects are discussed in this dissertation. First, High energy density capacitors where EPR measurements described herein provide an insight into structural and chemical differences in the dielectric material of a capacitor. Next, as the second project, Electrolyte solutions where an oxygen-17 NMR study has been employed to assess the degree of preferential solvation of Li+ ions in binary mixtures of EC (ethylene carbonate) and DMC (dimethyl carbonate) containing LiPF6 (lithium hexafluo-rophosphate) which may be ultimately related to the SEI formation mechanism. The third project was to study Bismuth fluoride as cathode material for rechargeable batteries. The objective was to study 19F and 7Li MAS NMR of some nanocomposite cathode materials as a conversion reaction occurring during lithiation and delithation of the BiF3/C nanocomposite.

  12. Advanced Energy Conversion Technologies and Architectures for Earth and Beyond

    NASA Technical Reports Server (NTRS)

    Howell, Joe T.; Fikes, John C.; Phillips, Dane J.; Laycock, Rustin L.; ONeill, Mark; Henley, Mark W.; Fork, Richard L.

    2006-01-01

    Research, development and studies of novel space-based solar power systems, technologies and architectures for Earth and beyond are needed to reduce the cost of clean electrical power for terrestrial use and to provide a stepping stone for providing an abundance of power in space, i.e., manufacturing facilities, tourist facilities, delivery of power between objects in space, and between space and surface sites. The architectures, technologies and systems needed for space to Earth applications may also be used for in-space applications. Advances in key technologies, i.e., power generation, power management and distribution, power beaming and conversion of beamed power are needed to achieve the objectives of both terrestrial and extraterrestrial applications. There is a need to produce "proof-ofconcept" validation of critical WPT technologies for both the near-term, as well as far-term applications. Investments may be harvested in near-term beam safe demonstrations of commercial WPT applications. Receiving sites (users) include ground-based stations for terrestrial electrical power, orbital sites to provide power for satellites and other platforms, future space elevator systems, space vehicle propulsion, and space surface sites. Space surface receiving sites of particular interest include the areas of permanent shadow near the moon s North and South poles, where WPT technologies could enable access to ice and other useful resources for human exploration. This paper discusses work addressing a promising approach to solar power generation and beamed power conversion. The approach is based on a unique high-power solar concentrator array called Stretched Lens Array (SLA) applied to both solar power generation and beamed power conversion. Since both versions (solar and laser) of SLA use many identical components (only the photovoltaic cells need to be different), economies of manufacturing and scale may be realized by using SLA on both ends of the laser power beaming system in a space solar power application. Near-term uses of this SLA-laser-SLA system may include terrestrial and space exploration in near Earth space. Later uses may include beamed power for bases or vehicles on Mars. Strategies for developing energy infrastructures in space which utilize this technology are presented. This dual use system produces electrical energy efficiently from either coherent light, such as from a highly coherent laser, or from conventional solar illumination. This allows, for example, supplementing solar energy with energy provided by highly coherent laser illumination during periods of low solar illumination or no illumination. This reduces the need for batteries and alternate sources of power. The capability of using laser illumination in a lowest order Gaussian laser mode provides means for transmitting power optically with maximum efficiency and precision over the long distances characteristic of space. A preliminary receiving system similar to that described here, has been produced and tested under solar and laser illumination. A summary of results is given.

  13. Oxidant system improvements for MHD energy conversion and industrial processes

    NASA Astrophysics Data System (ADS)

    Juhasz, A. J.

    1983-12-01

    An in-depth study was conducted to identify possible improvements to the oxidant supply system for combined cycle MHD power plants which would lead to higher thermal efficiency and reduction in the cost of electricity, COE. Results showed that the oxidant system energy consumption could be minimized when the process was designed to deliver a product O2 concentration of 70 mole percent. The study also led to the development of a new air separation process, referred to as 'liquid pumping and internal compression'. MHD system performance calculations show that the new process would permit an increase in plant thermal efficiency of 0.6 percent while allowing more favorable tradeoffs between magnetic energy and oxidant system capacity requirements.

  14. Direct energy conversion in fission reactors: A U.S. NERI project

    SciTech Connect

    SLUTZ,STEPHEN A.; SEIDEL,DAVID B.; POLANSKY,GARY F.; ROCHAU,GARY E.; LIPINSKI,RONALD J.; BESENBRUCH,G.; BROWN,L.C.; PARISH,T.A.; ANGHAIE,S.; BELLER,D.E.

    2000-05-30

    In principle, the energy released by a fission can be converted directly into electricity by using the charged fission fragments. The first theoretical treatment of direct energy conversion (DEC) appeared in the literature in 1957. Experiments were conducted over the next ten years, which identified a number of problem areas. Research declined by the late 1960's due to technical challenges that limited performance. Under the Nuclear Energy Research Initiative the authors are determining if these technical challenges can be overcome with todays technology. The authors present the basic principles of DEC reactors, review previous research, discuss problem areas in detail, and identify technological developments of the last 30 years that can overcome these obstacles. As an example, the fission electric cell must be insulated to avoid electrons crossing the cell. This insulation could be provided by a magnetic field as attempted in the early experiments. However, from work on magnetically insulated ion diodes they know how to significantly improve the field geometry. Finally, a prognosis for future development of DEC reactors will be presented .

  15. Proceedings of the 30. intersociety energy conversion engineering conference. Volume 3

    SciTech Connect

    Goswami, D.Y. [ed.] [Univ. of Florida, Gainesville, FL (United States); Kannberg, L.D.; Somasundaram, S. [eds.] [Pacific Northwest Lab., Richland, WA (United States); Mancini, T.R. [ed.] [Sandia National Labs., Albuquerque, NM (United States)

    1995-12-01

    This conference provides a forum to present and discuss the engineering aspects of energy conversion, advanced and unconventional energy systems and devices, energy conversion and utilization, environmental issues and policy implications on research, development, and implementation of technologies. The solution for a sustainable future will lie in a mix of all of the available energy resources (renewable and non-renewable) and diverse energy conversion technologies that will maintain quality of life in a sustainable manner. The 78 papers in this volume are divided into the following topical sections: (1) Conversion technologies--Heat pumps; Advanced cycles; Thermoelectrics; Thermionics; and AMTEC; (2) Electrochemical conversion--Fuel cells and Batteries for terrestrial applications; (3) New technologies for energy utilization (including Superconductivity); and (4) Stirling cycles and machines--Stirling engine development; Stirling component analysis/testing; Stirling machine simulation and optimization; and Stirling machine analysis. All papers have been processed separately for inclusion on the data base.

  16. Energy Conversion Advanced Heat Transport Loop and Power Cycle

    SciTech Connect

    Oh, C. H.

    2006-08-01

    The Department of Energy and the Idaho National Laboratory are developing a Next Generation Nuclear Plant (NGNP) to serve as a demonstration of state-of-the-art nuclear technology. The purpose of the demonstration is two fold 1) efficient low cost energy generation and 2) hydrogen production. Although a next generation plant could be developed as a single-purpose facility, early designs are expected to be dual-purpose. While hydrogen production and advanced energy cycles are still in its early stages of development, research towards coupling a high temperature reactor, electrical generation and hydrogen production is under way. Many aspects of the NGNP must be researched and developed in order to make recommendations on the final design of the plant. Parameters such as working conditions, cycle components, working fluids, and power conversion unit configurations must be understood. Three configurations of the power conversion unit were demonstrated in this study. A three-shaft design with 3 turbines and 4 compressors, a combined cycle with a Brayton top cycle and a Rankine bottoming cycle, and a reheated cycle with 3 stages of reheat were investigated. An intermediate heat transport loop for transporting process heat to a High Temperature Steam Electrolysis (HTSE) hydrogen production plant was used. Helium, CO2, and an 80% nitrogen, 20% helium mixture (by weight) were studied to determine the best working fluid in terms cycle efficiency and development cost. In each of these configurations the relative component size were estimated for the different working fluids. The relative size of the turbomachinery was measured by comparing the power input/output of the component. For heat exchangers the volume was computed and compared. Parametric studies away from the baseline values of the three-shaft and combined cycles were performed to determine the effect of varying conditions in the cycle. This gives some insight into the sensitivity of these cycles to various operating conditions as well as trade offs between efficiency and capital cost. Prametric studies were carried out on reactor outlet temperature, mass flow, pressure, and turbine cooling. Recommendations on the optimal working fluid for each configuration were made. A steady state model comparison was made with a Closed Brayton Cycle (CBC) power conversion system developed at Sandia National Laboratory (SNL). A preliminary model of the CBC was developed in HYSYS for comparison. Temperature and pressure ratio curves for the Capstone turbine and compressor developed at SNL were implemented into the HYSYS model. A comparison between the HYSYS model and SNL loop demonstrated power output predicted by HYSYS was much larger than that in the experiment. This was due to a lack of a model for the electrical alternator which was used to measure the power from the SNL loop. Further comparisons of the HYSYS model and the CBC data are recommended. Engineering analyses were performed for several configurations of the intermediate heat transport loop that transfers heat from the nuclear reactor to the hydrogen production plant. The analyses evaluated parallel and concentric piping arrangements and two different working fluids, including helium and a liquid salt. The thermal-hydraulic analyses determined the size and insulation requirements for the hot and cold leg pipes in the different configurations. Economic analyses were performed to estimate the cost of the va

  17. Energy magnetization and the thermal Hall effect.

    PubMed

    Qin, Tao; Niu, Qian; Shi, Junren

    2011-12-01

    We obtain a set of general formulas for determining magnetizations, including the usual electromagnetic magnetization as well as the gravitomagnetic energy magnetization. The magnetization corrections to the thermal transport coefficients are explicitly demonstrated. Our theory provides a systematic approach for properly evaluating the thermal transport coefficients of magnetic systems, eliminating the unphysical divergence from the direct application of the Kubo formula. For a noninteracting anomalous Hall system, the corrected thermal Hall conductivity obeys the Wiedemann-Franz law. PMID:22182111

  18. Design and simulation of MEMS based radioisotope converter with electrostatic capacitive energy conversion mechanism

    Microsoft Academic Search

    Haisheng San; Zaijun Cheng; Zhiqiang Deng; Zhiwen Zhao; Yanfei Li; Xuyuan Chen

    2011-01-01

    This paper presents the design and simulation of electrostatic capacitive vibration-to-electricity energy conversion system based on radioisotope Ni 63 that produces low energy beta particles. The electrostatic capacitive energy conversion utilizes a variable capacitor to convert radioisotope energy into electrical energy by mechanical vibration as transformed intermediate. The MEMS capacitor is designed as a radioisotope actuated parallel-plate spring-mass-damping structure fabricated

  19. Historical Overview and Fundamental Aspects of Molecular Catalysts for Energy Conversion

    Microsoft Academic Search

    T. Okada; T. Abe; M. Kaneko

    In this chapter we focus on the historical background of the electrocatalysts especially of molecular catalysts that are considered\\u000a as key technology for energy conversion systems. The energy conversion is a basic process with which humans can utilize natural\\u000a energy by converting into useful forms of energy such as heat, electricity, or other secondary energies. The most important\\u000a process to

  20. Investigation and development of new materials for electrochemical energy conversion

    NASA Astrophysics Data System (ADS)

    Ivanovskaya, Anna

    Performance of next generation electrochemical energy conversion devices relies on optimization of both ion selective membranes that retain conductivity at elevated temperatures, and electrode materials active and stable in corrosive environment. The work presented focuses on (1) improving energy conversion in fuel cells by designing novel ion conductive membrane materials optimized by an original optical high-throughput screening technique and (2) development of new stable mixed transition metal sulfide electrocatalysts for industrial bromine recovery. A functionalized fullerene derivative was used to fabricate mechanically strong, flexible organic-inorganic membranes via cooperative sol-gel synthesis. Amorphous materials with nanometer range wormlike structures were obtained. The dependence of conductivity on the concentration of triflic acid was quantitatively described by percolation theory. Fullerene derivatives with arbitrarily attached chains increased disorder of the structure, but before the wormlike network collapsed conductivity 40 times higher than that of the sample with no fullerenes was recorded. This enhancement was attributed to the additional inter-channel connections for proton transport facilitated by the fullerene derivatives. Optimization of the structure by an optical high-throughput screening made possible proton conductivity of 3.2x10-3 S/cm at 130°C and 5% humidity conditions. A series of doped Ru, Fe, Mo, W sulfide catalysts was synthesized, and their hydrogen evolution and oxygen reduction activity in HBr were studied as a function of dopant. RuS2 compounds showed the highest rates of hydrogen evolution and oxygen reduction reactions in HBr. Among all dopants, Co was the most active for hydrogen evolution reaction with overpotentials 100 mV lower than that of Pt at current density of 80 mA/cm2 in 0.5 M HBr. Oxygen reduction activity of RuS2 catalysts was found to change consistently as a function of periodic position of a dopant. Cr, Mn and Fe dopants inhibited oxygen reduction activity of RuS2, while Co, Ni and Cu promoted the activity. Inexpensive Ni-W sulfide was identified as active catalyst for oxygen reduction reaction in HBr. The activity increased with the addition of Ni up to 50%. Although Co-doped RuS2 is unstable in 6 M HBr, it was found to be stable under applied potential during 5 hour hydrogen evolution reaction test.

  1. January 2011: ME 533-Energy Conversion Dr. William M. Carey, Professor of Mechanical Engineering

    E-print Network

    of Energy Technologies -Nuclear, Solar, Wind, Oceanic and Fossil Fuels. 3.) Provide an analytical frame work and Ideal Gas Mixtures. 3) Energy Conversion systems-Coal-Oil-Nuclear, Oceanic, Solar, Geothermal and Wind notes and selected references for each major conversion system such as Wind, Solar, Nuclear, and Oceanic

  2. Selection of an asynchronized synchronous generator for a wind energy conversion system

    Microsoft Academic Search

    L. Ia. Shapiro; V. I. Astorga

    1986-01-01

    A wind energy conversion system with an asynchronized synchronous generator operating in parallel with a high-power network is described. Based on analysis of the range of efficient operating regimes of the wind energy conversion system, an optimum control algorithm is developed for the asynchronized synchronous generator which provides maximum power generation for a given range of rotation frequencies. Recommendations concerning

  3. ECUT (Energy Conversion and Utilization Technologies) program: Biocatalysis project

    NASA Technical Reports Server (NTRS)

    Baresi, Larry

    1989-01-01

    The Annual Report presents the fiscal year (FY) 1988 research activities and accomplishments, for the Biocatalysis Project of the U.S. Department of Energy, Energy Conversion and Utilization Technologies (ECUT) Division. The ECUT Biocatalysis Project is managed by the Jet Propulsion Laboratory, California Institute of Technology. The Biocatalysis Project is a mission-oriented, applied research and exploratory development activity directed toward resolution of the major generic technical barriers that impede the development of biologically catalyzed commercial chemical production. The approach toward achieving project objectives involves an integrated participation of universities, industrial companies and government research laboratories. The Project's technical activities were organized into three work elements: (1) The Molecular Modeling and Applied Genetics work element includes research on modeling of biological systems, developing rigorous methods for the prediction of three-dimensional (tertiary) protein structure from the amino acid sequence (primary structure) for designing new biocatalysis, defining kinetic models of biocatalyst reactivity, and developing genetically engineered solutions to the generic technical barriers that preclude widespread application of biocatalysis. (2) The Bioprocess Engineering work element supports efforts in novel bioreactor concepts that are likely to lead to substantially higher levels of reactor productivity, product yields and lower separation energetics. Results of work within this work element will be used to establish the technical feasibility of critical bioprocess monitoring and control subsystems. (3) The Bioprocess Design and Assessment work element attempts to develop procedures (via user-friendly computer software) for assessing the energy-economics of biocatalyzed chemical production processes, and initiation of technology transfer for advanced bioprocesses.

  4. An Application of Flywheel Energy Storage System for Wind Energy Conversion

    Microsoft Academic Search

    R. Takahashi; Li Wu; T. Murata; J. Tamura

    2005-01-01

    Recently, the use of wind energy conversion system (WECS) is increasing all over the world. Wind generators with several mega-watt rating have been developed and installed in wind farms, therefore, the influence of WECS on power system is becoming greater. Particularly a frequency variation of power system is a significant problem. This will damage to power quality, and cause a

  5. Photochemical conversion of solar energy in the environment. Book chapter

    SciTech Connect

    Zepp, R.G.

    1991-01-01

    Past research on photochemistry in the environment has focused on gas phase reactions in the atmosphere. Recently, however, environmentally significant photoreactions have been discovered in natural waters (i.e., the sea, lakes, and rivers), on soil surfaces, and in atmospheric condensed phases. These new investigations have been stimulated in part by interest in developing a scientific understanding of the role of photochemical processes in the biogeochemical cycles of various elements. In addition, other studies have explored the role of natural photochemical processes in cleansing the environemnt of various waste materials or, in some cases, in converting the wastes to more toxic substances. In the paper, current research results on the photochemical conversion of solar energy in aquatic environments and on soil and metal oxide surfaces are presented. Rate equations and products for selected homogeneous and heterogeneous photoreactions that occur in these systems are described. Data are presented for direct and sensitized photoreactions and for sunlight-initiated free radical reactions. (Copyright (c) 1991 Kluwer Academic Publishers.)

  6. New constraints and energy conversion efficiencies for plasma emission

    NASA Astrophysics Data System (ADS)

    Mitchell, J. J.; Cairns, I. H.; Robinson, P. A.

    2003-08-01

    Radio emission near the electron plasma frequency fp and 2fp due to electron beams is important in many laboratory and space applications. Langmuir waves produced as a result of these beams undergo various interactions leading to radio emission. Two categories of such interactions are decay processes involving ion acoustic waves and processes involving scattering off thermal ions (STI). In this paper energy conversion efficiencies for STI emission processes are derived. These are then compared with existing expressions for emission via decay. It is found that decay dominates STI processes when decay is able to proceed. Conditions are derived for emission near fp, and 2fp by decay processes. These depend on whether significant nonthermal levels of L' or S waves are produced by the initial nonlinear processes. These conditions are determined by comparing nonlinear growth rates with Landau damping rates. It is found that where the ratio of the beam speed to the electron thermal speed exceeds roughly 3-6, L'-waves persist and emission near 2fp can proceed. It is also found that when beams are sufficiently dense, cold, and fast, S-waves persist and emission near fp involving decay processes can proceed.

  7. 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.

  8. Advanced materials development for fossil energy conversion applications

    SciTech Connect

    Bates, J.L.; Chick, L.A.; Kingsley, J.J.; Pederson, L.R.; Weber, W.J.; Youngblood, G.E. (Pacific Northwest Lab., Richland, WA (United States)); Hurst, J.K.; Bell, A.E.; Grainger, D.W.; Rananavare, S.B.; Roe, D.K.; Thompson, D.H. (Oregon Graduate Inst. of Science and Technology, Beaverton, OR (United States))

    1992-05-01

    Research activities being conducted as part of this project include: (1) fundamental studies of electrochemical processes occurring at surfaces and interfaces in fuel cells, and (2) development of novel materials synthesis and processing methodologies for fossil energy conversion applications. Complex impedance and dc polarization studies of the electrocatalytic activity at the cathode have allowed intrinsic materials properties to be separated from extrinsic properties related to morphology. Mixed conduction in cathode materials was shown to dramatically enhance electrocatalytic activity with this approach. Combustion synthesis methods were used to prepare multicomponent perovskite catalysts in the La{sub 1-x}Sr{sub x}Co{sub 1-y}Fe{sub y}O{sub 3} system. Electronic properties of these catalysts can be altered by adjusting the composition, which affects both catalytic activity and selectivity. Inverse micelles have been utilized to prepare nanosized nickel sulfide particles, which show promise as hydrodesulfurization catalysts for liquefied coal. Self-assembling organic monolayers and derivatized inorganic surfaces have been used to control nucleation and crystal morphology of inorganic phases.

  9. Fluidized-bed energy technology for biomass conversion

    SciTech Connect

    Soltes, E.J.; Lepori, W.A.; Pollock, T.C.

    1982-01-01

    Fluidized-bed technology offers several unique features for use in small-scale biomass energy conversion. Results are reported in the use of a 61-cm fluidized-bed reactor for combustion and on the use of 61-, 30-, and 5-cm reactors for gasification. combustion trials using agricultural biomass feeds have identified several problem areas. Slagging and fouling can occur at bed temperatures as low as 760/sup 0/C. Moreover, metal coupons placed in the hot exhaust gas stream experienced high rates of corrosion and erosion. Gasification experiments have confirmed that a fluidized bed will accept a wide range of biomass feeds (rice hulls, corncobs, sorghum stalks, cottom gin trash) and convert them into a low-Btu combustible gas. Slagging and fouling were not as severe when operating the fluidized bed in the gasification mode. Gas cleanup requirements as well as technical needs in evaluating corrosion of reactor construction materials are identified. Coupling of the 61-cm reactor to a steam boiler is described. Finally, the nature of fluidized-bed technology suggests potentials for biomass pyrolysis, and such use is examined. 2 figures, 5 tables.

  10. Exciton fission and solar energy conversion beyond the limit

    NASA Astrophysics Data System (ADS)

    Zhu, Xiaoyang

    2014-03-01

    The absorption of one photon by a semiconductor material usually creates one electron-hole pair, but this general rule breaks down in a few organic semiconductors, such as pentacene and tetracene, where one photon absorption may result in two electron-hole pairs in a process called singlet exciton. Recent measurements in our group by time-resolved two-photon photoemission (TR-2PPE) spectroscopy in crystalline pentacene and tetracene provided the first spectroscopic signatures in singlet fission of a critical intermediate known as the multiexciton state. More importantly, population of the multiexciton state is found to rise concurrently with that of the singlet state on the ultrafast time scale upon photo excitation. This observation provides an experimental foundation for a quantum coherent mechanism in which the electronic coupling creates a quantum superposition of the singlet and the multiexciton state immediately following optical excitation. We demonstrate the feasibility of harvesting the multiexciton state for multiple charge carriers and the implementation of singlet fission for solar energy conversion beyond the Shockley-Queisser limit.

  11. Amphoteric oxide semiconductors for energy conversion devices: a tutorial review.

    PubMed

    Singh, Kalpana; Nowotny, Janusz; Thangadurai, Venkataraman

    2013-03-01

    In this tutorial review, we discuss the defect chemistry of selected amphoteric oxide semiconductors in conjunction with their significant impact on the development of renewable and sustainable solid state energy conversion devices. The effect of electronic defect disorders in semiconductors appears to control the overall performance of several solid-state ionic devices that include oxide ion conducting solid oxide fuel cells (O-SOFCs), proton conducting solid oxide fuel cells (H-SOFCs), batteries, solar cells, and chemical (gas) sensors. Thus, the present study aims to assess the advances made in typical n- and p-type metal oxide semiconductors with respect to their use in ionic devices. The present paper briefly outlines the key challenges in the development of n- and p-type materials for various applications and also tries to present the state-of-the-art of defect disorders in technologically related semiconductors such as TiO(2), and perovskite-like and fluorite-type structure metal oxides. PMID:23257778

  12. Draft environmental assessment: Ocean Thermal Energy Conversion (OTEC) Pilot Plants

    SciTech Connect

    Sullivan, S.M.; Sands, M.D.; Donat, J.R.; Jepsen, P.; Smookler, M.; Villa, J.F.

    1981-02-01

    This Environmental Assessment (EA) has been prepared, in accordance with the National Environmental Policy Act of 1969, for the deployment and operation of a commercial 40-Megawatt (MW) Ocean Thermal Energy Conversion (OTEC) Pilot Plant (hereafter called the Pilot Plant). A description of the proposed action is presented, and a generic environment typical of the candidate Pilot Plant siting regions is described. An assessment of the potential environmental impacts associated with the proposed action is given, and the risk of credible accidents and mitigating measures to reduce these risks are considered. The Federal and State plans and policies the proposed action will encompass are described. Alternatives to the proposed action are presented. Appendix A presents the navigation and environmental information contained in the US Coast Pilot for each of the candidate sites; Appendix B provides a brief description of the methods and calculations used in the EA. It is concluded that environmental disturbances associated with Pilot Plant activities could potentially cause significant environmental impacts; however, the magnitude of these potential impacts cannot presently be assessed, due to insufficient engineering and environmental information. A site- and design-specific OTEC Pilot Plant Environmental Impact Statement (EIS) is required to resolve the potentially significant environmental effects associated with Pilot Plant deployment and operation. (WHK)

  13. Energy transport velocity in bidispersed magnetic colloids.

    PubMed

    Bhatt, Hem; Patel, Rajesh; Mehta, R V

    2012-07-01

    Study of energy transport velocity of light is an effective background for slow, fast, and diffuse light and exhibits the photonic property of the material. We report a theoretical analysis of magnetic field dependent resonant behavior in forward-backward anisotropy factor, light diffusion constant, and energy transport velocity for bidispersed magnetic colloids. A bidispersed magnetic colloid is composed of micrometer size magnetic spheres dispersed in a magnetic nanofluid consisting of magnetic nanoparticles in a nonmagnetic liquid carrier. Magnetic Mie resonances and reduction in energy transport velocity accounts for the possible delay (longer dwell time) by field dependent resonant light transport. This resonant behavior of light in bidispersed magnetic colloids suggests a novel magnetophotonic material. PMID:23005411

  14. Modeling and analysis of hybrid geothermal-solar thermal energy conversion systems

    E-print Network

    Greenhut, Andrew David

    2010-01-01

    Innovative solar-geothermal hybrid energy conversion systems were developed for low enthalpy geothermal resources augmented with solar energy. The goal is to find cost-effective hybrid power cycles that take advantage of ...

  15. Recovery Act: Integrated DC-DC Conversion for Energy-Efficient Multicore Processors

    SciTech Connect

    Shepard, Kenneth L

    2013-03-31

    In this project, we have developed the use of thin-film magnetic materials to improve in energy efficiency of digital computing applications by enabling integrated dc-dc power conversion and management with on-chip power inductors. Integrated voltage regulators also enables fine-grained power management, by providing dynamic scaling of the supply voltage in concert with the clock frequency of synchronous logic to throttle power consumption at periods of low computational demand. The voltage converter generates lower output voltages during periods of low computational performance requirements and higher output voltages during periods of high computational performance requirements. Implementation of integrated power conversion requires high-capacity energy storage devices, which are generally not available in traditional semiconductor processes. We achieve this with integration of thin-film magnetic materials into a conventional complementary metal-oxide-semiconductor (CMOS) process for high-quality on-chip power inductors. This project includes a body of work conducted to develop integrated switch-mode voltage regulators with thin-film magnetic power inductors. Soft-magnetic materials and inductor topologies are selected and optimized, with intent to maximize efficiency and current density of the integrated regulators. A custom integrated circuit (IC) is designed and fabricated in 45-nm CMOS silicon-on-insulator (SOI) to provide the control system and power-train necessary to drive the power inductors, in addition to providing a digital load for the converter. A silicon interposer is designed and fabricated in collaboration with IBM Research to integrate custom power inductors by chip stacking with the 45-nm CMOS integrated circuit, enabling power conversion with current density greater than 10A/mm2. The concepts and designs developed from this work enable significant improvements in performance-per-watt of future microprocessors in servers, desktops, and mobile devices. These new approaches to scaled voltage regulation for computing devices also promise significant impact on electricity consumption in the United States and abroad by improving the efficiency of all computational platforms. In 2006, servers and datacenters in the United States consumed an estimated 61 billion kWh or about 1.5% of the nation's total energy consumption. Federal Government servers and data centers alone accounted for about 10 billion kWh, for a total annual energy cost of about $450 million. Based upon market growth and efficiency trends, estimates place current server and datacenter power consumption at nearly 85 billion kWh in the US and at almost 280 billion kWh worldwide. Similar estimates place national desktop, mobile and portable computing at 80 billion kWh combined. While national electricity utilization for computation amounts to only 4% of current usage, it is growing at a rate of about 10% a year with volume servers representing one of the largest growth segments due to the increasing utilization of cloud-based services. The percentage of power that is consumed by the processor in a server varies but can be as much as 30% of the total power utilization, with an additional 50% associated with heat removal. The approaches considered here should allow energy efficiency gains as high as 30% in processors for all computing platforms, from high-end servers to smart phones, resulting in a direct annual energy savings of almost 15 billion kWh nationally, and 50 billion kWh globally. The work developed here is being commercialized by the start-up venture, Ferric Semiconductor, which has already secured two Phase I SBIR grants to bring these technologies to the marketplace.

  16. Efficiency evaluation of oxygen enrichment in energy conversion processes

    SciTech Connect

    Bomelburg, H.J.

    1983-12-01

    The extent to which energy conversion efficiencies can be increased by using oxygen or oxygen-enriched air for combustion was studied. Combustion of most fuels with oxygen instead of air was found to have five advantages: increases combustion temperature and efficiency, improves heat transfer at high temperatures, reduces nitrous oxide emissions, permits a high ration of exhaust gas recirculation and allows combustion of certain materials not combustible in air. The same advantages, although to a lesser degree, are apparent with oxygen-enriched air. The cost-effectiveness of the process must necessarily be improved by about 10% when using oxygen instead of air before such use could become justifiable on purely economic terms. Although such a modest increase appears to be attainable in real situations, this study ascertained that it is not possible to generally assess the economic gains. Rather, each case requires its own evaluation. For certain processes industry has already proven that the use of oxygen leads to more efficient plant operation. Several ideas for essentially new applications are described. Specifically, when oxygen is used with exhaust gas recirculation in external or internal combustion engines. It appears also that the advantages of pulse combustion can be amplified further if oxygen is used. When burning wet fuels with oxygen, direct steam generation becomes possible. Oxygen combustion could also improve processes for in situ gasification of coals, oil shales, peats, and other wet fuels. Enhanced oil recovery by fire flooding methods might also become more effective if oxygen is used. The cold energy contained in liquid oxygen can be substantially recovered in the low end of certain thermodynamic cycles. Further efforts to develop certain schemes for using oxygen for combustion appear to be justified from both the technical and economic viewpoints.

  17. Summary of State-of-the-Art Power Conversion Systems for Energy Storage Applications

    SciTech Connect

    Atcitty, S.; Gray-Fenner, A.; Ranade, S.

    1998-09-01

    The power conversion system (PCS) is a vital part of many energy storage systems. It serves as the interface between the storage device, an energy source, and an AC load. This report summarizes the results of an extensive study of state-of-the-art power conversion systems used for energy storage applications. The purpose of the study was to investigate the potential for cost reduction and performance improvement in these power conversion systems and to provide recommendations for fiture research and development. This report provides an overview of PCS technology, a description of several state-of-the-art power conversion systems and how they are used in specific applications, a summary of four basic configurations for l:he power conversion systems used in energy storage applications, a discussion of PCS costs and potential cost reductions, a summary of the stancku-ds and codes relevant to the technology, and recommendations for future research and development.

  18. Semiconductor Physics and Quantum Solar Energy Conversion PV-related research at CvO University Oldenburg

    E-print Network

    Semiconductor Physics and Quantum Solar Energy Conversion PV-related research at CvO University Oldenburg GRECO Cvo UNI OL/ Nds.PV-Symp. 06-2009 semiconductor physics / quantum solar energy conversion;Semiconductor Physics and Quantum Solar Energy Conversion Semiconductor Physics and Quantum Solar Energy

  19. Mode conversion and absorption of fast waves at high ion cyclotron harmonics in inhomogeneous magnetic fields

    NASA Astrophysics Data System (ADS)

    Cho, Suwon; Kwak, Jong-Gu

    2014-04-01

    The propagation and absorption of high harmonic fast waves is of interest for non-inductive current drives in fusion experiments. The fast wave can be coupled with the ion Bernstein wave that propagates in the high magnetic field side of an ion cyclotron harmonic resonance layer. This coupling and the absorption are analyzed using the hot plasma dispersion relation and a wave equation that was converted from an approximate dispersion relation for the case where ?i=k?2?i2/2?1 (where k? is the perpendicular wave number and ?i is the ion Larmor radius). It is found that both reflection and conversion may occur near the harmonic resonance layer but that they decrease rapidly, giving rise to a sharp increase in the absorption as the parallel wave number increases.

  20. High-frequency mode conversion technique for stiff lesion detection with magnetic resonance elastography (MRE).

    PubMed

    Mariappan, Yogesh K; Glaser, Kevin J; Manduca, Armando; Romano, Anthony J; Venkatesh, Sudhakar K; Yin, Meng; Ehman, Richard L

    2009-12-01

    A novel imaging technique is described in which the mode conversion of longitudinal waves is used for the qualitative detection of stiff lesions within soft tissue using magnetic resonance elastography (MRE) methods. Due to the viscoelastic nature of tissue, high-frequency shear waves attenuate rapidly in soft tissues but much less in stiff tissues. By introducing minimally-attenuating longitudinal waves at a significantly high frequency into tissue, shear waves produced at interfaces by mode conversion will be detectable in stiff regions, but will be significantly attenuated and thus not detectable in the surrounding soft tissue. This contrast can be used to detect the presence of stiff tissue. The proposed technique is shown to readily depict hard regions (mimicking tumors) present in tissue-simulating phantoms and ex vivo breast tissue. In vivo feasibility is demonstrated on a patient with liver metastases in whom the tumors are readily distinguished. Preliminary evidence also suggests that quantitative stiffness measurements of stiff regions obtained with this technique are more accurate than those from conventional MRE because of the short shear wavelengths. This rapid, qualitative technique may lend itself to applications in which the localization of stiff, suspicious neoplasms is coupled with more sensitive techniques for thorough characterization. PMID:19859936

  1. Biomass conversion Task 4 1988 program of work: International Energy Agency Bioenergy Agreement

    SciTech Connect

    Stevens, D.J.

    1987-12-01

    For biomass to meet its potential as an energy resource, conversion processes must be available which are both efficient and environmentally acceptable. Conversion can include direct production of heat and electricity as well as production of intermediate gaseous, liquid, and solid fuels. While many biomass conversion processes are commercially available at present, others are still in the conceptual stage. Additional research and development activities on these advanced concepts will be necessary to fully use biomass resources. Ongoing research on biomass conversion processes is being conducted by many nations throughout the world. In an effort to coordinate this research and improve information exchange, several countries have agreed to a cooperative effort through the International Energy Agency's Bioenergy Agreement (IEA/BA). Under this Agreement, Task IV deals specifically with biomass conversion topics. The cooperative activities consists of information exchange and coordination of national research programs on specific topics. The activities address biomass conversion in a systematic manner, dealing with the pretreatment of biomass prior to conversion, the subsequent conversion of the biomass to intermediate fuels or end-product energy, and then the environmental aspects of the conversion process. This document provides an outline of cooperative work to be performed in 1988. 1 fig., 2 tabs.

  2. Flywheel energy storage with superconductor magnetic bearings

    SciTech Connect

    Weinberger, B.R.; Lynds, L. Jr.

    1993-06-01

    A system for storing energy in a flywheel suspended by magnetic levitation in a vacuum vessel is described comprising: a rotatable member having a rotation axis in a central shaft said shaft having first and second magnetic tips formed from permanent magnets on opposite ends thereof, superconductor magnetic bearings, positioned to support said first and second magnetic tips and supported in turn by bearing support means, said superconductor magnetic bearings having a main direction of lift; cooling means in thermal contact with said bearing support means; and energy transfer means, connected to said rotatable member, for transferring energy into and extracting energy from said rotatable member, characterized in that: at least one of said superconducting bearings includes a lifting portion comprising melt-processed, directionally solidified material structure having a crystal structure C-axis oriented parallel to said main direction of lift.

  3. Energy transfer up-conversion in Tm3+ -doped silica fibre

    E-print Network

    Paris-Sud XI, Université de

    infra-red up-conversion in thulium doped silica fibres is presented. Up-conversion luminescence crystals [1-4]. The low phonon energies associated with fluoride crystals allow many of the thulium percent. Although recent work in thulium doped silica fibres showed a four fold increase in the quantum

  4. Pyroelectric energy conversion using PLZT ceramics and the ferroelectricergodic relaxor phase transition

    E-print Network

    Pilon, Laurent

    Pyroelectric energy conversion using PLZT ceramics and the ferroelectric­ergodic relaxor phase conversion using PLZT ceramics and the ferroelectric­ergodic relaxor phase transition Felix Y Lee, Hwan Ryul titanate (PLZT) ceramics undergoing a relaxor­ferroelectric phase transition. The Olsen cycle consists

  5. The behavior of magneto-acoustic-gravity waves near the cusp resonance in a lossless, compressible, isothermal, stratified, electrically conducting, and uniformly magnetized atmosphere. I. Mode conversion approach

    SciTech Connect

    Kamp, L. P. J.

    1989-07-01

    In the present paper the propagation of (internal) magneto-acoustic-gravitywaves is analyzed in a compressible, isothermal, stratified, electricallyconducting atmosphere that is permeated by a uniform, nearly horizontal magneticfield. The conversion, near the so-called cusp resonance of a longacoustic-gravity wave into a short slow magneto-acoustic wave, is demonstratedby means of boundary layer theory based on the smallness of the verticalcomponent of the magnetic field. The magneto-acoustic wave subsequently carriesthe energy off upward, which in the limit of a horizontal magnetic field wouldbe fed into the cusp resonance /ital ad//nfinitum/. This gives rise to singularfields. The scaling of the tendency toward singular behavior of a field quantitywith the obliqueness of the magnetic field is discussed, as well as the partialreflection of the long acoustic-gravity wave.

  6. Biomass Conversion Task IV 1987 program of work: International Energy Agency Bioenergy Agreement

    SciTech Connect

    Stevens, D.J.

    1986-12-01

    Biomass is a major, renewable energy resource through out the world, and extensive research is being conducted by many countries on bioenergy technologies. In an effort to improve communications and cooperation in the area of biomass energy, several nations have agreed to a cooperative program of work under the International Energy Agency's Bioenergy Agreement (IEA/BA). Three areas of major importance have been identified including Short Rotation Forestry, Conventional Forestry, and Biomass Conversion. This document describes the 1987 Program of Work for cooperative activities in the area of Biomass Conversion. The background of the cooperation and descriptions of specific conversion projects are presented. Details of activity funding are also provided. 3 tabs.

  7. Selective absorbers and interference filters for thermophotovoltaic energy conversion

    NASA Astrophysics Data System (ADS)

    Hoefler, H.; Paul, H. J.; Ruppel, W.; Wuerfel, P.

    The thermophotovoltaic (TPV) conversion process is investigated in detail. Selective intermediate emitters and black intermediate emitters combined with a 7-layer interference band-pass filter are considered separately. Selective emitters give good performance only with small-bandgap solar cells. The emitter temperature must be around 2000 K, where evaporation is excessive. Black emitters combined with filters must be operated at high temperatures for cells with a bandgap greater than 1 eV. Small-bandgap cells require lower emitter temperatures and give the best TPV conversion efficiency, which for Ge-cells is 1.7 times better than for direct conversion with Si cells at an emitter temperature of 1800 K, where tungsten shows good long-term stability.

  8. Optimized Helium-Brayton Power Conversion for Fusion Energy Systems

    SciTech Connect

    Zhao Haihua [University of California at Berkeley (United States); Fukuda, Grant [University of California at Berkeley (United States); Abbott, Ryan P. [Lawrence Livermore National Laboratory (United States); Peterson, Per F. [University of California at Berkeley (United States)

    2005-04-15

    This paper presents an overview and a few point designs for multiple-reheat helium Brayton cycle power conversion systems using molten salts (or liquid metals or direct helium cooling). All designs are derived from the General Atomics GT-MHR power conversion unit (PCU). The important role of compact, offset fin heat exchangers for heat transfer to the power cycle helium, and the potential for these to be fabricated from carbon-coated composite materials that would have lower potential for fouling, are discussed. Specific links are made to the ITER TBM and laser IFE blanket design, and to Z-Pinch/HIF thick-liquid IFE.

  9. Magnetic properties and energy-mapping analysis.

    PubMed

    Xiang, Hongjun; Lee, Changhoon; Koo, Hyun-Joo; Gong, Xingao; Whangbo, Myung-Hwan

    2013-01-28

    The magnetic energy levels of a given magnetic solid are closely packed in energy because the interactions between magnetic ions are weak. Thus, in describing its magnetic properties, one needs to generate its magnetic energy spectrum by employing an appropriate spin Hamiltonian. In this review article we discuss how to determine and specify a necessary spin Hamiltonian in terms of first principles electronic structure calculations on the basis of energy-mapping analysis and briefly survey important concepts and phenomena that one encounters in reading the current literature on magnetic solids. Our discussion is given on a qualitative level from the perspective of magnetic energy levels and electronic structures. The spin Hamiltonian appropriate for a magnetic system should be based on its spin lattice, i.e., the repeat pattern of its strong magnetic bonds (strong spin exchange paths), which requires one to evaluate its Heisenberg spin exchanges on the basis of energy-mapping analysis. Other weaker energy terms such as Dzyaloshinskii-Moriya (DM) spin exchange and magnetocrystalline anisotropy energies, which a spin Hamiltonian must include in certain cases, can also be evaluated by performing energy-mapping analysis. We show that the spin orientation of a transition-metal magnetic ion can be easily explained by considering its split d-block levels as unperturbed states with the spin-orbit coupling (SOC) as perturbation, that the DM exchange between adjacent spin sites can become comparable in strength to the Heisenberg spin exchange when the two spin sites are not chemically equivalent, and that the DM interaction between rare-earth and transition-metal cations is governed largely by the magnetic orbitals of the rare-earth cation. PMID:23128376

  10. Contribution of chemistry to energy. [Fuels from coal; solar energy storage\\/conversion

    Microsoft Academic Search

    Cox

    1978-01-01

    Chemistry has contributed in many ways to energy production and conversion in the fossil fuel era. The challenges facing chemists and chemical engineers as we look forward to the 21st Century are addressed. This paper discusses some of the means that can be employed to meet this challenge both in the near-term and long-term, particularly alternate fuels from coal and

  11. Performance of a 10 MW geothermal energy conversion test facility

    Microsoft Academic Search

    W. O. Jacobson

    1978-01-01

    The performance of San Diego Gas & Electric's Geothermal Loop Facility has been generally good. Comparison of initial flash\\/binary conversion cycle selection criteria to performance data has led to renewed interest in a flash cycle. Brine system performance has been generally successful but hampered by scale accumulation. Improved scale removal and control techniques are being evaluated. Geothermal steam and condensate

  12. ENERGY SPECTRUM OF INTERNAL CONVERSION PAIRS PRODUCED IN RADIATIVE THERMAL NEUTRON CAPTURE IN Gd

    Microsoft Academic Search

    G. V. Danilyan; I. Ya. Korolkov

    1962-01-01

    An improved magnetic double-spectrometer with 4 x 10⁻⁹ sec ; resolving power, oriented to 0 and 60 deg geometric angle between recorded pair ; components and equipped with scinttllation counters was used in an investigation ; of the angular distribution between electron-positron internal conversion pairs. ; The geometric scheme of the 45-mm diameter, 5- mu -thick aluminum foil exposed to

  13. Mode conversion of Langmuir to electromagnetic waves at magnetic field-aligned density inhomogeneities: Simulations, theory, and applications to the solar wind and the corona

    SciTech Connect

    Kim, Eun-Hwa; Cairns, Iver H.; Robinson, Peter A. [School of Physics, University of Sydney, New South Wales 2006 (Australia)

    2008-10-15

    Linear mode conversion of Langmuir waves to radiation near the plasma frequency at density gradients is potentially relevant to multiple solar radio emissions, ionospheric radar experiments, laboratory plasma devices, and pulsars. Here we study mode conversion in warm magnetized plasmas using a numerical electron fluid simulation code with the density gradient parallel to the ambient magnetic field B{sub 0} for a range of incident Langmuir wavevectors. Our results include: (1) both o- and x-mode waves are produced for {omega}=({omega}L/c){sup 1/3}({omega}{sub c}/{omega})(less-or-similar sign)1, contrary to previous ideas. Only the o mode is produced for {omega}(greater-or-similar sign)1.5. Here {omega}{sub c} is the (angular) electron cyclotron frequency, {omega} is the angular wave frequency, L is the length scale of the (linear) density gradient, and c is the speed of light. A WKB-style analysis accounts semiquantitatively for the production and relative conversion efficiencies of the o and x modes in the simulations. (2) In the unmagnetized limit, equal amounts of o- and x-mode radiation are produced. (3) The mode conversion window narrows as {omega} increases. (4) As {omega} increases the total electromagnetic field changes from linear to circular polarization, with the o- and x-mode signals remaining circularly polarized. (5) The conversion efficiency to the x mode decreases monotonically as {omega} increases while the o-mode conversion efficiency oscillates due to an interference phenomenon between incoming and reflected Langmuir/z modes. (6) The maximum total conversion efficiencies for wave power from the Langmuir/z mode to radiation are of order 50%-70%. They depend strongly on the wave frequency when close to the background plasma frequency but weakly on the electron temperature T{sub 0} and {beta}=T{sub 0}/mc{sup 2}. The corresponding energy conversion efficiencies are favored since they allow separation into o and x modes, use directly measured experimental quantities, and generalize easily for wave packets. The total energy conversion efficiency differs from the power conversion efficiency by the ratio of the group speeds for each mode, is less than 10% for the value of {beta}=0.01 simulated, and decreases linearly with {beta}. Since {beta}{approx_equal}10{sup -5}-10{sup -4} in the solar wind and corona, this {beta} dependence is important in applications. (7) The interference effect and the disappearance of the x mode at {omega}(greater-or-similar sign)1 can be accounted for semiquantitatively using a WKB-type analysis. (8) Constraints on density turbulence are developed for the x mode to be generated and be able to propagate from the source. (9) Standard parameters for the corona and the solar wind near 1 AU suggest that linear mode conversion should produce both o- and x-mode radiation for solar and interplanetary radio bursts. It is therefore possible that linear mode conversion under these conditions might explain the weak total circular polarizations of type II and III solar radio bursts.

  14. Chemomechanics of ionically conductive ceramics for electrical energy conversion and storage

    E-print Network

    Swallow, Jessica Gabrielle

    Functional materials for energy conversion and storage exhibit strong coupling between electrochemistry and mechanics. For example, ceramics developed as electrodes for both solid oxide fuel cells and batteries exhibit ...

  15. Nanostructural engineering of vapor-processed organic photovoltaics for efficient solar energy conversion from any Surface

    E-print Network

    Macko, Jill Annette (Jill Annette Rowehl)

    2014-01-01

    More than two billion people in the world have little or no access to electricity. To be empowered they need robust and lightweightrenewable energy conversion technologies that can be easily transported with high yield ...

  16. Status and summary of laser energy conversion. [for space power transmission systems

    NASA Technical Reports Server (NTRS)

    Lee, G.

    1978-01-01

    This paper presents a survey of the status of laser energy converters. Since the inception of these devices in the early 1970's, significant advances have been made in understanding the basic conversion processes. Numerous theoretical and experimental studies have indicated that laser energy can be converted at wavelengths from the ultraviolet to the far-infrared. These converters can be classified into five general categories: photovoltaics, heat engines, thermoelectronic, optical diode, and photochemical. The conversion can be directly into electricity (such as the photovoltaic, thermoelectronic, and optical diode) or it can go through an intermediate stage of conversion to mechanical energy, as in the heat engines. The photochemical converters result in storable energy such as hydrogen. Projected conversion efficiencies range from about 30% for the photochemical to nearly 75% for the heat engines.

  17. Exploring electron and phonon transport at the nanoscale for thermoelectric energy conversion

    E-print Network

    Minnich, Austin Jerome

    2011-01-01

    Thermoelectric materials are capable of solid-state direct heat to electricity energy conversion and are ideal for waste heat recovery applications due to their simplicity, reliability, and lack of environmentally harmful ...

  18. Recent developments in high-temperature photonic crystals for energy conversion

    E-print Network

    Rinnerbauer, Veronika

    After decades of intense studies focused on cryogenic and room temperature nanophotonics, scientific interest is also growing in high-temperature nanophotonics aimed at solid-state energy conversion. These latest extensive ...

  19. Global energy conversion rate from geostrophic flows into internal lee waves in the deep ocean

    E-print Network

    Nikurashin, Maxim

    A global estimate of the energy conversion rate from geostrophic flows into internal lee waves in the ocean is presented. The estimate is based on a linear theory applied to bottom topography at O(1–10) km scales obtained ...

  20. Exploring heat transfer at the atomistic level for thermal energy conversion and management

    E-print Network

    Tian, Zhiting

    2014-01-01

    Heat transfer at the scales of atoms plays an important role in many applications such as thermoelectric energy conversion and thermal management of microelectronic devices. While nanoengineering offers unique opportunities ...

  1. Broken Bar Detection in Synchronous Machines Based Wind Energy Conversion System

    E-print Network

    Rahimian, Mina Mashhadi

    2012-10-19

    BROKEN BAR DETECTION IN SYNCHRONOUS MACHINES BASED WIND ENERGY CONVERSION SYSTEM A Dissertation by MINA MASHHADI RAHIMIAN Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... of the requirements for the degree of DOCTOR OF PHILOSOPHY August 2011 Major Subject: Electrical Engineering BROKEN BAR DETECTION IN SYNCHRONOUS MACHINES BASED WIND ENERGY CONVERSION SYSTEM A Dissertation by MINA MASHHADI RAHIMIAN...

  2. Relationship between thermoelectric figure of merit and energy conversion efficiency.

    PubMed

    Kim, Hee Seok; Liu, Weishu; Chen, Gang; Chu, Ching-Wu; Ren, Zhifeng

    2015-07-01

    The formula for maximum efficiency (?max) of heat conversion into electricity by a thermoelectric device in terms of the dimensionless figure of merit (ZT) has been widely used to assess the desirability of thermoelectric materials for devices. Unfortunately, the ?max values vary greatly depending on how the average ZT values are used, raising questions about the applicability of ZT in the case of a large temperature difference between the hot and cold sides due to the neglect of the temperature dependences of the material properties that affect ZT. To avoid the complex numerical simulation that gives accurate efficiency, we have defined an engineering dimensionless figure of merit (ZT)eng and an engineering power factor (PF)eng as functions of the temperature difference between the cold and hot sides to predict reliably and accurately the practical conversion efficiency and output power, respectively, overcoming the reporting of unrealistic efficiency using average ZT values. PMID:26100905

  3. Sensorless maximum power point tracking control in wind energy generation using permanent magnet synchronous generator

    Microsoft Academic Search

    N. Srighakollapu; P. S. Sensarma

    2008-01-01

    This paper proposes a control strategy for variable speed wind energy conversion system (WECS), incorporating maximum power point tracking (MPPT) algorithm, using direct driven permanent magnet synchronous generator (PMSG). The generator is operated in the speed control mode below the base speed by controlling the terminal voltage using three phase front-end active-rectifier feeding power to the DC bus. The voltage

  4. A less sensor control method for standalone small wind energy using Permanent Magnet Synchronous Generator

    Microsoft Academic Search

    Mohamed Hilmy; Mohamed Orabi; Mahrous E. Ahmed; Mohamed El-Nemr; Mohamed Youssef

    2011-01-01

    this paper proposes a new control strategy using less number of sensors for variable speed wind energy conversion system (WECS). Maximum Power Point Tracking (MPPT) algorithm, and near unity power factor correction control (UPF) are achieved at the generator side using direct driven Permanent Magnet Synchronous Generator (PMSG). The PMSG operates at variable wind speed connected to a full controlled

  5. High Energy Utilization, Co-Generation Nuclear power Plants With Static Energy Conversion

    SciTech Connect

    El-Genk, Mohamed S.; Tournier, Jean-Michel P. [Institute for Space and Nuclear Power Studies and Chemical and Nuclear Engineering Department, The University of New Mexico, Albuquerque, NM (United States)

    2002-07-01

    In addition to being cost effective, very small nuclear power plants with static energy conversion could meet the needs and the energy mix in underdeveloped countries and remote communities, which may include electricity, residential and industrial space heating, seawater desalination, and/or high temperature process heat or steam for industrial uses. These plants are also an attractive option in naval, marine, and undersea applications, when the absence of a sound signature is highly desirable. An Analysis is performed of Gas Cooled Reactor (CGR) and Liquid Metal Cooled Reactor (LMR), very small nuclear power plants with static energy conversion, using a combination of options. These include Alkali Metal Thermal-to-Electric Converters (AMTECs) and both single segment and segmented thermoelectric converters. The total energy utilization of these plants exceeds 88%. It includes the fraction of the reactor's thermal power converted into electricity and delivered to the Grid at 6.6 kVA and those used for residential and industrial space heating at {approx}370 K, seawater desalination at 400 K, and/or high temperature process heat or steam at {approx}850 K. In addition to its inherently high reliability, modularity, low maintenance and redundancy, static energy conversion used in the present study could deliver electricity to the Grid at a net efficiency of 29.5%. A LMR plant delivers 2-3 times the fraction of the reactor thermal power converted into electricity in a GCR plant, but could not provide for both seawater desalination and high temperature process heat/steam concurrently, which is possible in GCR plants. The fraction of the reactor's thermal power used for non-electrical power generation in a GCR plant is {approx} 10 - 15% higher than in a LMR plant. (authors)

  6. The Magnetic Free Energy in Active Regions

    NASA Technical Reports Server (NTRS)

    Metcalf, Thomas R.; Mickey, Donald L.; LaBonte, Barry J.

    2001-01-01

    The magnetic field permeating the solar atmosphere governs much of the structure, morphology, brightness, and dynamics observed on the Sun. The magnetic field, especially in active regions, is thought to provide the power for energetic events in the solar corona, such as solar flares and Coronal Mass Ejections (CME) and is believed to energize the hot coronal plasma seen in extreme ultraviolet or X-rays. The question remains what specific aspect of the magnetic flux governs the observed variability. To directly understand the role of the magnetic field in energizing the solar corona, it is necessary to measure the free magnetic energy available in active regions. The grant now expiring has demonstrated a new and valuable technique for observing the magnetic free energy in active regions as a function of time.

  7. Proceedings of the 26th intersociety energy conversion engineering conference

    SciTech Connect

    Not Available

    1991-01-01

    Renewable Resource Systems; Developments in Nuclear Power, Energy from Waste and Biomass, Photovoltaics, Solar Thermal Energy, wind Energy Systems, Stirling Engines and Applications Systems and Cycles, Advanced Co-Generation, AMTEC, Fossil Fuel Systems and Technologies, Marine Energy.

  8. Correlation of energy conversion efficiency and interface polarization in niobate glass-ceramic for energy-storage applications

    NASA Astrophysics Data System (ADS)

    Xue, Shuangxi; Liu, Shaohui; Zhang, Wenqin; Shen, Bo; Zhai, Jiwei

    2015-04-01

    The correlation between energy conversion efficiency and interface polarization was investigated according to the discharge performance and impedance spectroscopy as a function of annealing temperatures in BaO-Na2O-Nb2O5-SiO2 glass ceramic system. The experiment results show that the energy conversion efficiency strongly depends on the interface polarization. The annealing temperature dependence of the energy conversion efficiency is attributed to the variation of interfacial polarization, according to the results of complex impedance analysis.

  9. 29th Intersociety energy conversion engineering conference: Technical papers. Part 4

    SciTech Connect

    Not Available

    1994-01-01

    Part 4 of these proceedings contains 76 papers covering the following topics: Energy from waste and biomass; Geothermal; Hydrogen energy systems; Photovoltaics; Solar thermal energy--Thermal power conversion; Solar thermal energy--Innovative applications; Solar thermal energy--Heating and cooling; Wind systems; Reusable energy--Status and the future; Stirling coolers and heat pumps; Stirling cycle analysis; and Stirling power generation. All of the papers have been processed for inclusion on the data base.

  10. 2012: ME 533-Energy Conversion Dr. William M. Carey, Professor of Mechanical Engineering

    E-print Network

    2012: ME 533-Energy Conversion Dr. William M. Carey, Professor of Mechanical Engineering Office for the comparsion of the energy/environmental /economic factors. 4.) Provide a perspective of the scope of the National and International Energy Research, Development, and Production by: 1.) reviewing the Department

  11. Novel multi-mode single leg converter for renewable energy conversion systems

    Microsoft Academic Search

    Taehyung Kim

    2011-01-01

    The digital revolution and faster switching devices have introduced more sophisticated control systems that require high quality and reliable operation. The rapidly growing demand for alternative\\/renewable energy generation systems and use of energy sources on a large scale, require new technologies. In this paper, a novel renewable energy conversion system, which has the reduced number of switching elements preserving the

  12. Optimum control strategies in energy conversion of PMSG wind turbine system without mechanical sensors

    Microsoft Academic Search

    Kelvin Tan; Syed Islam

    2004-01-01

    The amount of energy obtained from a wind energy conversion system (WECS) depends not only on the characteristics of the wind regime at the site, but it also depends on the control strategy used for the WECS. In order to determine the gain in energy derived from one concept as compared against another, models of several autonomous WECS have been

  13. High Temperature Fusion Reactor Cooling Using Brayton Cycle Based Partial Energy Conversion

    Microsoft Academic Search

    Albert J. Juhasz; Jerzy T. Sawicki

    2004-01-01

    For some future space power systems using high temperature nuclear heat sources most of the output energy will be used in other than electrical form, and only a fraction of the total thermal energy generated will need to be converted to electrical work. The paper describes the conceptual design of such a ``partial energy conversion'' system, consisting of a high

  14. Resonant Conversion of Photon Modes Due to Vacuum Polarization in a Magnetized Plasma: Implications for X-Ray Emission from Magnetars

    E-print Network

    Dong Lai; Wynn C. G. Ho

    2001-10-18

    It is known that vacuum polarization can modify the photon propagation modes in the atmospheric plasma of a strongly magnetized neutron star. A resonance occurs when the effect of vacuum polarization on the photon modes balances that of the plasma. We show that a photon (with energy $E\\go$ a few keV) propagating outward in the atmosphere can convert from one polarization mode into another as it traverses the resonant density, $\\rho_{res}\\simeq Y_e^{-1}\\eta^{-2}(B/10^{14} G)^2(E/1 keV)^2$ g cm$^{-3}$, where $Y_e$ is the electron fraction, and $\\eta\\sim 1$ is a slowly varying function of the magnetic field $B$. The physics of this mode conversion is analogous to the Mikheyev-Smirnov-Wolfenstein mechanism for neutrino oscillation. Because the two photon modes have vastly different opacities in the atmosphere, this vacuum-induced mode conversion can significantly affect radiative transport and surface emission from strongly magnetized neutron stars.

  15. ENERGY CARRIERS AND CONVERSION SYSTEMS WITH EMPHASIS ON HYDROGEN

    Microsoft Academic Search

    Tokio Ohta; T. Nejat Veziroglu

    Summary This theme level article introduces the background and outline of hydrogen energy systems and the relevant elementary technologies. The most significant points are as follows: • Energy, energy resources, and energy carriers are defined. The merits and the demerits of every energy resource are pointed out. It is emphasized that the combination of every traditional system with hydrogen systems

  16. The potential impact of ZT=4 thermoelectric materials on solar thermal energy conversion technologies.

    SciTech Connect

    Xie, M.; Gruen, D. M.; Materials Science Division; Michigan Technological Univ.

    2010-03-02

    State-of-the-art methodologies for the conversion of solar thermal power to electricity are based on conventional electromagnetic induction techniques. If appropriate ZT = 4 thermoelectric materials were available, it is likely that conversion efficiencies of 30-40% could be achieved. The availability of all solid state electricity generation would be a long awaited development in part because of the elimination of moving parts. This paper presents a preliminary examination of the potential performance of ZT = 4 power generators in comparison with Stirling engines taking into account specific mass, volume and cost as well as system reliability. High-performance thermoelectrics appear to have distinct advantages over magnetic induction technologies.

  17. Solar energy conversion via hot electron internal photoemission in metallic nanostructures: Efficiency estimates

    SciTech Connect

    Leenheer, Andrew J.; Narang, Prineha; Atwater, Harry A., E-mail: haa@caltech.edu [Thomas J. Watson Laboratories of Applied Physics, California Institute of Technology, Pasadena, California 91125 (United States); Joint Center for Artificial Photosynthesis, Pasadena, California 91125 (United States); Lewis, Nathan S. [Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125 (United States); Joint Center for Artificial Photosynthesis, Pasadena, California 91125 (United States)

    2014-04-07

    Collection of hot electrons generated by the efficient absorption of light in metallic nanostructures, in contact with semiconductor substrates can provide a basis for the construction of solar energy-conversion devices. Herein, we evaluate theoretically the energy-conversion efficiency of systems that rely on internal photoemission processes at metal-semiconductor Schottky-barrier diodes. In this theory, the current-voltage characteristics are given by the internal photoemission yield as well as by the thermionic dark current over a varied-energy barrier height. The Fowler model, in all cases, predicts solar energy-conversion efficiencies of <1% for such systems. However, relaxation of the assumptions regarding constraints on the escape cone and momentum conservation at the interface yields solar energy-conversion efficiencies as high as 1%–10%, under some assumed (albeit optimistic) operating conditions. Under these conditions, the energy-conversion efficiency is mainly limited by the thermionic dark current, the distribution of hot electron energies, and hot-electron momentum considerations.

  18. Stirling engine versus steam engine for rural energy conversion

    SciTech Connect

    Rice, G.

    1984-08-01

    The Stirling engine shows promise for conversion of heat from combustion of agricultural waste to mechanical power. The air charged engine produced by Sunpower Inc., USA, for Bangladesh, having a rice husk burner, is an example of such a development. The paper deals with the performance analysis of this system in terms of the temperature of combustion and heat transfer to the engine both with and without waste heat recovery. The system performance is compared to that of a system utilising a steam Rankine cycle in place of the Stirling engine. In the case of no waste heat recovery the comparison is based on the Availability ratio for each system.

  19. Solvent conversion in refinery treating system results in energy savings

    SciTech Connect

    Cox, S.; Henry, T.; McDougal, K.; Daughtry, J.

    1987-01-01

    GAS/SPEC SS Selective Solvent was first used in the amine section of GFU 244 at the Chevron (Port Arthur, Texas) Refinery during 1985 as a replacement for DEA (Diethanolamine). Since converting to GAS/SPEC SS Selective Solvent, the process parameters have been monitored closely to evaluate changes in utility requirements, solvent circulation rates and operating costs. Current operating conditions and annual operating costs were compared to the performance of DEA preceding the May, 1985 conversion. The results are summarized in this paper.

  20. Effect of biomass feedstock chemical and physical properties on energy conversion processes: Volume 2, Appendices

    SciTech Connect

    Butner, R.S.; Elliott, D.C.; Sealock, L.J., Jr.; Pyne, J.W.

    1988-12-01

    This report presents an exploration of the relationships between biomass feedstocks and the conversion processes that utilize them. Specifically, it discusses the effect of the physical and chemical structure of biomass on conversion yields, rates, and efficiencies in a wide variety of available or experimental conversion processes. A greater understanding of the complex relationships between these conversion systems and the production of biomass for energy uses is required to help optimize the complex network of biomass production, collection, transportation, and conversion to useful energy products. The review of the literature confirmed the scarcity of research aimed specifically at identifying the effect of feedstock properties on conversion. In most cases, any mention of feedstock-related effects was limited to a few brief remarks (usually in qualitative terms) in the conclusions, or as a topic for further research. Attempts to determine the importance of feedstock parameters from published data were further hampered by the lack of consistent feedstock characterization and the difficulty of comparing results between different experimental systems. Further research will be required to establish quantitative relationships between feedstocks and performance criteria in conversion. 127 refs., 4 figs., 7 tabs.

  1. Engineering light: advances in wavelength conversion materials for energy and environmental technologies.

    PubMed

    Cates, Ezra L; Chinnapongse, Stephanie L; Kim, Jae-Hyuk; Kim, Jae-Hong

    2012-11-20

    Upconversion photoluminescence (UC) occurs in optical materials that are capable of absorbing low energy photons and emitting photons of higher energy and shorter wavelength, while downconversion (DC) materials may absorb one high energy photon and emit two of lower energy for quantum yields exceeding unity. These wavelength conversion processes allow us to transform electromagnetic radiation so it may be more effectively utilized by light-capturing devices and materials. Progress in designing more efficient organic and inorganic photochemical conversion systems has initiated a recent surge in attempts to apply these processes for practical uses, including enhancement of many energy and environmental technologies. In this review, we introduce important concepts in UC and DC materials and discuss the current status and challenges toward the application of wavelength conversion to solar cells, photocatalysis, and antimicrobial surfaces. PMID:23113803

  2. High-temperature inert gas plasma magnetohydrodynamic energy conversion by using linear-shaped Faraday-type channel

    NASA Astrophysics Data System (ADS)

    Murakami, Tomoyuki; Zhuang, Yunqin; Okuno, Yoshihiro

    2013-02-01

    We describe high-density magnetohydrodynamic (MHD) energy conversion in a high-temperature seed-free argon plasma, for which a compact linear-shaped Faraday-type MHD electrical power generator is used. Short-time-duration single-pulse shock-tunnel-based experiments demonstrate the MHD energy conversion with varying total inflow temperature up to 9000 K and applied magnetic-flux density up to 4.0 T. The high-temperature plasma is transformed from the thermal-equilibrium state at the entrance to the weak-nonequilibrium state in the supersonic MHD channel. The discharge structure is reasonably homogeneous without suffering from serious streamer development. The power generation performance is monotonically improved by increasing total inflow temperature and strength of magnetic field. The enthalpy extraction efficiency of 13.1% and overall power density of 0.16 GW/m3 are attained. The local power density at the middle of the channel reaches 0.24 GW/m3.

  3. Permanent Magnet Spiral Motor for Magnetic Gradient Energy Utilization: Axial Magnetic Field

    NASA Astrophysics Data System (ADS)

    Valone, Thomas F.

    2010-01-01

    The Spiral Magnetic Motor, which can accelerate a magnetized rotor through 90% of its cycle with only permanent magnets, was an energy milestone for the 20th century patents by Kure Tekkosho in the 1970's. However, the Japanese company used old ferrite magnets which are relatively weak and an electrically-powered coil to jump start every cycle, which defeated the primary benefit of the permanent magnet motor design. The principle of applying an inhomogeneous, anisotropic magnetic field gradient force Fz = ? cos ? dB/dz, with permanent magnets is well-known in physics, e.g., Stern-Gerlach experiment, which exploits the interaction of a magnetic moment with the aligned electron spins of magnetic domains. In this case, it is applied to dB/d? in polar coordinates, where the force F? depends equally on the magnetic moment, the cosine of the angle between the magnetic moment and the field gradient. The radial magnetic field increases in strength (in the attractive mode) or decreases in strength (in the repulsive mode) as the rotor turns through one complete cycle. An electromagnetic pulsed switching has been historically used to help the rotor traverse the gap (detent) between the end of the magnetic stator arc and the beginning (Kure Tekko, 1980). However, alternative magnetic pulse and switching designs have been developed, as well as strategic eddy current creation. This work focuses on the switching mechanism, novel magnetic pulse methods and advantageous angular momentum improvements. For example, a collaborative effort has begun with Toshiyuki Ueno (University of Tokyo) who has invented an extremely low power, combination magnetostrictive-piezoelectric (MS-PZT) device for generating low frequency magnetic fields and consumes "zero power" for static magnetic field production (Ueno, 2004 and 2007a). Utilizing a pickup coil such as an ultra-miniature millihenry inductor with a piezoelectric actuator or simply Wiegand wire geometry, it is shown that the necessary power for magnetic field switching device can be achieved in order to deflect the rotor magnet in transit. The Wiegand effect itself (bistable FeCoV wire called "Vicalloy") invented by John Wiegand (Switchable Magnetic Device, US Patent ?4,247,601), utilizing Barkhausen jumps of magnetic domains, is also applied for a similar achievement (Dilatush, 1977). Conventional approaches for spiral magnetic gradient force production have not been adequate for magnetostatic motors to perform useful work. It is proposed that integrating a magnetic force control device with a spiral stator inhomogeneous axial magnetic field motor is a viable approach to add a sufficient nonlinear boundary shift to apply the angular momentum and potential energy gained in 315 degrees of the motor cycle.

  4. Importance of barrier layers in thermal diodes for energy conversion

    NASA Astrophysics Data System (ADS)

    Kucherov, Yan; Hagelstein, Peter; Sevastyanenko, Victor; Brown, Harold L.; Guruswamy, Sivaraman; Wingert, Wayne

    2005-05-01

    Very high thermal to electric conversion efficiencies have been reported previously with thermal diode structures in which a thin n-type emitter layer is formed on the hot side of a thick near-intrinsic thermoelectric semiconductor. The figure of merit derived from direct measurements of electrical parameters and heat flow is increased by as much as a factor of eight. The question of what physical mechanisms are involved has been of interest since the initial observations of the effect. We have conjectured that the short-circuit current injection in these experiments is due to a second-order thermionic injection mechanism. More recently, we proposed that the open-circuit voltage comes about due to the presence of a p-type blocking layer between the emitter and the near-intrinsic bulk region. The experiments reported here show that a p-type blocking layer is required for the effect, and the dependence of conversion efficiency on the blocking layer concentration and width is studied. The results are generally consistent with calculations done so far based on a nonlocal generalized Onsager-type transport model.

  5. Modeling Energy Recovery Using Thermoelectric Conversion Integrated with an Organic Rankine Bottoming Cycle

    Microsoft Academic Search

    Erik W. Miller; Terry J. Hendricks; Richard B. Peterson

    2009-01-01

    Engine and industrial waste heat are sources of high-grade thermal energy that can potentially be utilized. This paper describes\\u000a a model system that employs thermoelectric conversion as a topping cycle integrated with an organic Rankine bottoming cycle.\\u000a The model has many parameters that define combined system quantities such as overall output power and conversion efficiency.\\u000a The model can identify the

  6. Investigation of current university research concerning energy conversion and conservation in small single-family dwellings

    NASA Technical Reports Server (NTRS)

    Grossman, G. R.; Roberts, A. S., Jr.

    1975-01-01

    An investigation was made of university research concerning energy conversion and conservation techniques which may be applied in small single-family residences. Information was accumulated through published papers, progress reports, telephone conversations, and personal interviews. A synopsis of each pertinent investigation is given. Finally, a discussion of the synopses is presented and recommendations are made concerning the applicability of concepts for the design and construction of NASA-Langley Research Center's proposed Technology Utilization House in Hampton, Virginia.

  7. Polyoxometalate-conductive polymer composites for energy conversion, energy storage and nanostructured sensors.

    PubMed

    Herrmann, Sven; Ritchie, Chris; Streb, Carsten

    2015-04-28

    The exchange of electric charges between a chemical reaction centre and an external electrical circuit is critical for many real-life technologies. This perspective explores the "wiring" of highly redox-active molecular metal oxide anions, so-called polyoxometalates (POMs) to conductive organic polymers (CPs). The major synthetic approaches to these organic-inorganic hybrid materials are reviewed. Typical applications are highlighted, emphasizing the current bottlenecks in materials development. Utilization of the composites in the fields of energy conversion, electrochemical energy storage, sensors and nanoparticle "wiring" into conductive materials are discussed. The outlook section presents the authors' views on emerging fields of research where the combination of POMs and CPs can be expected to provide novel materials for groundbreaking new technologies. These include light-weight energy storage, high-sensitivity toxin sensors, artificial muscles, photoelectrochemical devices and components for fuel cells. PMID:25787774

  8. Application of Nuclear Energy to Bitumen Upgrading and Biomass Conversion

    SciTech Connect

    Mamoru Numata; Yasushi Fujimura [JGC Corporation (Japan); Takayuki Amaya [Ministry of Education, Culture, Sports, Science and Technology - MEXT, Japan 2-5-1 Marunouchi Chiyoda-ku, Tokyo 100-8959 (Japan); Masao Hori [Nuclear Systems Association, 1-7-6 Toranomon Tokyo, 105-0001 (Japan)

    2006-07-01

    Key drivers for the increasing use of nuclear energy are the need to mitigate global warming and the requirement for energy security. Nuclear energy can be applied not only to generate electricity but also as a heat source. Moreover, nuclear energy can be applied for hydrogen as well as water production. The application of nuclear energy to oil processing and biomass production is studied in this paper. (authors)

  9. Magnetic materials and devices for the 21st century: stronger, lighter, and more energy efficient.

    PubMed

    Gutfleisch, Oliver; Willard, Matthew A; Brück, Ekkes; Chen, Christina H; Sankar, S G; Liu, J Ping

    2011-02-15

    A new energy paradigm, consisting of greater reliance on renewable energy sources and increased concern for energy efficiency in the total energy lifecycle, has accelerated research into energy-related technologies. Due to their ubiquity, magnetic materials play an important role in improving the efficiency and performance of devices in electric power generation, conditioning, conversion, transportation, and other energy-use sectors of the economy. This review focuses on the state-of-the-art hard and soft magnets and magnetocaloric materials, with an emphasis on their optimization for energy applications. Specifically, the impact of hard magnets on electric motor and transportation technologies, of soft magnetic materials on electricity generation and conversion technologies, and of magnetocaloric materials for refrigeration technologies, are discussed. The synthesis, characterization, and property evaluation of the materials, with an emphasis on structure-property relationships, are discussed in the context of their respective markets, as well as their potential impact on energy efficiency. Finally, considering future bottlenecks in raw materials, options for the recycling of rare-earth intermetallics for hard magnets will be discussed. PMID:21294168

  10. Hybrid offshore-wind and tidal turbine (HOTT) energy Conversion I.. (6-pulse GTO rectifier and inverter)

    Microsoft Academic Search

    Mohammad Lutfur Rahman; Yasuyuki Shirai

    2008-01-01

    The innovative renewable energy conversion system called ldquoHybrid Offshore-wind and Tidal Turbinerdquo (HOTT) Conversion was proposed. The research includes tidal turbine and offshore-wind turbine, new turbine designs, turbine control of tidal energy and offshore-wind energy absorption, hydrodynamic characteristics, energy conversion, overall design methods, moorings and foundation and system resonance. HOTT will be entire five turbines, four turbines will be tidal

  11. Research on energy conversion mechanism of a screw centrifugal pump under the water

    NASA Astrophysics Data System (ADS)

    Quan, H.; Li, R. N.; Su, Q. M.; Han, W.; Cheng, X. R.; Shen, Z. J.

    2013-12-01

    In order to research screw centrifugal pump impeller power capability and energy conversion mechanism, we used Navier-Stokes equation and standard k-? equation turbulence model on the basis of the Euler equations to carry out screw centrifugal pump internal flow numerical simulation. This was explored by simulating specific design conditions; the medium is water, variation of speed and pressure of flow filed under the action of the impeller, and the screw centrifugal impeller shroud line and wheel line segment take monitoring sites. The monitoring points are between dynamic head and static head change to analyze the energy conversion capability along the impeller corners of screw centrifugal pump. The results show that the energy of fluid of the screw centrifugal pump is provided by spiral segment, the spiral segment in front of the impeller has played a multi-level role, it has significant reference value to research the energy conversion mechanism of screw centrifugal pump under solid-liquid two phase.

  12. 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.

  13. Wet chemical synthesis of multicomponent hexaferrites by gel-to-crystallite conversion and their magnetic properties

    NASA Astrophysics Data System (ADS)

    Sudakar, C.; Subbanna, G. N.; Kutty, T. R. N.

    2003-07-01

    The hexaferrites of different compositions from the BaO-NiO-Fe 2O 3 ternary phase diagram were prepared by a wet chemical process of gel-to-crystallite conversion. Herein, the coprecipitated reactive gels of hydrated nFe(OH) 3· pNi(OH) 2· xH 2O; 70< x<110 with n=12-36 and p=0-2 were reacted with mBa(OH) 2·8H 2O ( m=0-4) in aqueous ethanol medium at 80°C yielding the precursors of the general formula Ba mFe nNi pO q(OH) r· sH 2O ( q=13-35; r=6-50; s=5-30) which are crystalline by electron diffraction. Dehydroxylation of the precursor is accomplished by continuous weight loss as evidenced from thermogravimetry and is complete at ˜650°C by isothermal conditions. Differential thermal analysis showed exothermic peaks arising from the recrystallization followed by grain growth of the particles at ˜750°C. Direct phase evolution of hexaferrites are evidenced from X-ray diffraction studies. Monophasic nanoparticles of hexaferrites were obtained on heat-treating the precursor at 850°C. HREM of these crystallites show defect-free, regular, coherent growth of structural blocks. The evolution of para- to ferrimagnetic phase on heat-treatment is continuous and is through the superparamagnetic state. This is associated with a continuous increase in magnetization with heat-treatment temperature. Samples heat-treated below 850°C show diffuse magnetic transition near Tc, which results from the intergrowths observed in the lattices. Hysteresis loop for various compositions showed significant differences from hard ferrite characteristics for M-phase ( ? s=52 emu/g; Hc=4520 Oe) to soft ferrite ( ?s=25.5 emu/g; Hc=205 Oe) for Y-phase. Crystallographic domains of complex stacking sequences such as YMYM 4, M 2SM 3S, MMYY, etc. are observed when the hexaferrites are heat-treated above 1350°C.

  14. Static power conversion techniques for unique energy devices 

    E-print Network

    Welch, Richard Andrew

    1998-01-01

    Solar power, fuel cells, and supercapacitors are some hics. of the new energy devices that are being used today in various power applications. The first two of these devices are exciting alternative sources of clean energy. The third device...

  15. The wells air turbine for wave energy conversion

    Microsoft Academic Search

    S. Raghunathan

    1995-01-01

    The wave energy devices currently in operation in the United Kingdom and India and those that are to be built in Europe are based on the principle of the oscillating water-air column. In these devices the pneumatic energy of the oscillating air column is converted to mechanical energy of rotation by a Wells turbine. A monoplane (single plane) Wells turbine

  16. A universal electromagnetic energy conversion adapter based on a metamaterial absorber.

    PubMed

    Xie, Yunsong; Fan, Xin; Wilson, Jeffrey D; Simons, Rainee N; Chen, Yunpeng; Xiao, John Q

    2014-01-01

    On the heels of metamaterial absorbers (MAs) which produce near perfect electromagnetic (EM) absorption and emission, we propose a universal electromagnetic energy conversion adapter (UEECA) based on MA. By choosing the appropriate energy converting sensors, the UEECA is able to achieve near 100% signal transfer ratio between EM energy and various forms of energy such as thermal, DC electric, or higher harmonic EM energy. The inherited subwavelength dimension and the EM field intensity enhancement can further empower UEECA in many critical applications such as energy harvesting, photoconductive antennas, and nonlinear optics. The principle of UEECA is understood with a transmission line model, which further provides a design strategy that can incorporate a variety of energy conversion devices. The concept is experimentally validated at a microwave frequency with a signal transfer ratio of 96% by choosing an RF diode as the energy converting sensor. PMID:25200005

  17. A universal electromagnetic energy conversion adapter based on a metamaterial absorber

    NASA Astrophysics Data System (ADS)

    Xie, Yunsong; Fan, Xin; Wilson, Jeffrey D.; Simons, Rainee N.; Chen, Yunpeng; Xiao, John Q.

    2014-09-01

    On the heels of metamaterial absorbers (MAs) which produce near perfect electromagnetic (EM) absorption and emission, we propose a universal electromagnetic energy conversion adapter (UEECA) based on MA. By choosing the appropriate energy converting sensors, the UEECA is able to achieve near 100% signal transfer ratio between EM energy and various forms of energy such as thermal, DC electric, or higher harmonic EM energy. The inherited subwavelength dimension and the EM field intensity enhancement can further empower UEECA in many critical applications such as energy harvesting, photoconductive antennas, and nonlinear optics. The principle of UEECA is understood with a transmission line model, which further provides a design strategy that can incorporate a variety of energy conversion devices. The concept is experimentally validated at a microwave frequency with a signal transfer ratio of 96% by choosing an RF diode as the energy converting sensor.

  18. A Brief Status on Condition Monitoring and Fault Diagnosis in Wind Energy Conversion Systems

    E-print Network

    Paris-Sud XI, Université de

    --There is a constant need for the reduction of operational and maintenance costs of Wind Energy Conversion Systems a proactive response, minimizing downtime, and maximizing productivity. Wind generators are also inaccessible of plants components. This way, overall maintenance costs and downtime of wind energy converters can

  19. Thermal Sciences The thermal sciences area involves the study of energy conversion and transmission, power

    E-print Network

    New Hampshire, University of

    Thermal Sciences The thermal sciences area involves the study of energy conversion and transmission, power generation, the flow of liquids and gases, and the transfer of thermal energy (heat) by means and an airplane can be propelled forward. The processes involved are a superb example of thermal science processes

  20. New methods for the conversion of solar energy to R. F. and laser power

    Microsoft Academic Search

    J. W. Freeman; W. B. Colson; S. Simons

    1979-01-01

    This paper discusses two new devices which may have application to space deployed solar energy conversion and transmission systems, the photoklystron and the free electron laser. The photoklystron converts solar energy directly to RF radiation. It operates on the principle of the klystron with the cathode replaced by a photoemitting surface. We have tested a model which oscillates at 30

  1. Global green energy conversion revolution in 21st century through solid state devices

    Microsoft Academic Search

    R. Singh; N. Gupta; K. F. Poole

    2008-01-01

    Rising demands of energy in emerging economies coupled with the green house gas emissions related problems around the globe have provided a unique opportunity of exploiting the advantages offered by solid state devices (photovoltaic devices, thermoelectric devices, light emitting devices etc.) for green energy conversion. Similar to cell phones, power generation by photovoltaics (PV) can reach over two billion people

  2. Thermal insulation research plan for the Energy Conversion and Utilization Technologies (ECUT) materials program

    Microsoft Academic Search

    1986-01-01

    This report documents both the process and the output of the process of establishing a peer review panel primarily from the private sector to suggest research and development activities appropriate for government sponsorship through the US Department of Energy (DOE) Energy Conversion and Utilization Technologies (ECUT) Program on the subject of thermal insulation. We expect to use information and guidance

  3. Energy conversion by photoelectrolysis of water: Determination of efficiency by in situ photocalorimetry

    SciTech Connect

    Dohrmann, J.K.; Schaaf, N.S. [Freie Universitaet Berlin (Germany)

    1992-05-28

    The authors study energy efficiency measurements for the photoelectrolysis of water in a cell with a semiconductor photoanode illuminated by monochromatic light. Comparisons of different efficiency measures of such cells has been a problem for the intercomparison of published work on such photoelectrolysis cells. They look at a heat monitoring signal from the photoanode in relationship to the energy conversion efficiency of the cell.

  4. Single-phase self-excited inductor alternators for renewable energy electric conversion systems

    Microsoft Academic Search

    N. Kumaresan; M. Subbiah; R. Karthigaivel

    2011-01-01

    Single-phase inductor alternators have been shown to be suitable for use with renewable energy electric conversion systems for small power applications. Since both the field and the ac output winding are on the stator, these alternators, in respect of construction and maintenance, have all the advantages of self-excited induction generators presently being employed with renewable energy sources. An attempt has

  5. LDRD final report : energy conversion using chromophore-functionalized carbon nanotubes

    Microsoft Academic Search

    Andrew L. Vance; Thomas Zifer; Xinjian Zhou; Francois Leonard Leonard; Bryan Matthew Wong; Alexander Kane; Aaron Michael Katzenmeyer; Karen Lee Krafcik

    2010-01-01

    With the goal of studying the conversion of optical energy to electrical energy at the nanoscale, we developed and tested devices based on single-walled carbon nanotubes functionalized with azobenzene chromophores, where the chromophores serve as photoabsorbers and the nanotube as the electronic read-out. By synthesizing chromophores with specific absorption windows in the visible spectrum and anchoring them to the nanotube

  6. Aero-Acoustic Analysis of Wells Turbine for Ocean Wave Energy Conversion

    E-print Network

    Frandsen, Jannette B.

    Aero-Acoustic Analysis of Wells Turbine for Ocean Wave Energy Conversion Ralf Starzmann Fluid of harnessing the energy from ocean waves is the oscillating water column (OWC) device. The OWC converts degradation of stall margin and sound emission. SEMINAR To receive ORE Seminar announcements by e-mail, please

  7. Understanding Power Electronics and Electrical Machines in Multidisciplinary Wind Energy Conversion System Courses

    ERIC Educational Resources Information Center

    Duran, M. J.; Barrero, F.; Pozo-Ruz, A.; Guzman, F.; Fernandez, J.; Guzman, H.

    2013-01-01

    Wind energy conversion systems (WECS) nowadays offer an extremely wide range of topologies, including various different types of electrical generators and power converters. Wind energy is also an application of great interest to students and with a huge potential for engineering employment. Making WECS the main center of interest when teaching…

  8. Liquid phase thermochemical energy conversion systems - An application of Diels-Alder chemistry

    Microsoft Academic Search

    T. G. Lenz; L. S. Hegedus; J. D. Vaughan

    1982-01-01

    A method of thermochemical energy conversion, transport, and storage research involving moderate and low temperature liquid phase systems employing Diels-Alder cycloaddition chemistry is described. Proposed as a heat storage system for solar and industrial waste heat, the system involves the meeting, in a reactor, of energy-depleted and energy-rich fluids. The poor fluid gains energy and goes through a chemical, endothermic

  9. Mode Conversion and Absorption of Lower Hybrid Waves in Inhomogeneous Magnetic Fields

    Microsoft Academic Search

    Suwon Cho

    1987-01-01

    When a cold lower hybrid wave propagates in an inhomogeneous plasma, it undergoes a total mode conversion to the warm wave which is then coupled with the ion Bernstein wave around ion cyclotron harmonic frequencies. Both types of linear mode conversion problems can be described by fourth order differential equations if the two processes are separated from each other. The

  10. (Coal conversion, renewable energy and energy efficiency in India): Foreign trip report, October 31, 1988December 8, 1988

    Microsoft Academic Search

    1988-01-01

    The US Agency for International Development (USAID) Mission in New Delhi, India, as part of the ongoing Alternative Energy Resources Development (AERD) Project, is initiating follow-on projects related to coal conversion, renewable energy, and energy efficiency. A four-member team was invited to India for three weeks to assist the mission in identifying the activities to be undertaken and the institutional

  11. Vibration-to-electric energy conversion using a mechanically-varied capacitor

    E-print Network

    Yen, Bernard Chih-Hsun, 1981-

    2005-01-01

    Past research in vibration energy harvesting has focused on the use of variable capacitors, magnets, or piezoelectric materials as the basis of energy transduction. How- ever, few of these studies have explored the detailed ...

  12. Energy Conversion Alternatives Study (ECAS), General Electric Phase 1. Volume 3: Energy conversion subsystems and components. Part 3: Gasification, process fuels, and balance of plant

    NASA Technical Reports Server (NTRS)

    Boothe, W. A.; Corman, J. C.; Johnson, G. G.; Cassel, T. A. V.

    1976-01-01

    Results are presented of an investigation of gasification and clean fuels from coal. Factors discussed include: coal and coal transportation costs; clean liquid and gas fuel process efficiencies and costs; and cost, performance, and environmental intrusion elements of the integrated low-Btu coal gasification system. Cost estimates for the balance-of-plant requirements associated with advanced energy conversion systems utilizing coal or coal-derived fuels are included.

  13. Energy Conversion Alternatives Study (ECAS), Westinghouse phase 1. Volume 1: Introduction and summary and general assumptions. [energy conversion systems for electric power plants using coal - feasibility

    NASA Technical Reports Server (NTRS)

    Beecher, D. T.

    1976-01-01

    Nine advanced energy conversion concepts using coal or coal-derived fuels are summarized. They are; (1) open-cycle gas turbines, (2) combined gas-steam turbine cycles, (3) closed-cycle gas turbines, (4) metal vapor Rankine topping, (5) open-cycle MHD; (6) closed-cycle MHD; (7) liquid-metal MHD; (8) advanced steam; and (9) fuel cell systems. The economics, natural resource requirements, and performance criteria for the nine concepts are discussed.

  14. Energy partition in magnetic reconnection outflows

    NASA Astrophysics Data System (ADS)

    Eastwood, J. P.; Phan, T.; Drake, J. F.; Shay, M. A.

    2012-12-01

    The basic plasma process of magnetic reconnection plays an important role in plasma dynamics in a variety of solar, space, and astrophysical environments. In particular, it converts stored magnetic energy into directed jets and particle heating. An important issue is therefore to understand how magnetic reconnection distributes the released energy into different forms. The partition of energy in reconnection outflows has mainly been investigated in the context of the Earth's magnetotail and solar flares using single fluid simulations. However, the recent discovery of significant Poynting flux associated with kinetic Alfven wave structure emanating from the diffusion region along and near the separatrices means that a re-assessment of the energy partition in reconnection outflows is required, particularly from the experimental point of view. Here we present new measurements of plasma energetics in the vicinity of the diffusion region. Using data from Cluster and examining a series of reconnection events observed in the Earth's magnetotail, we present an analysis of the statistical properties of plasma in the ion diffusion region associated with the magnetic reconnection X-line. In particular, we investigate the partition of energy between the enthalpy, kinetic energy and Poynting fluxes, and the spatial structure of these fluxes relative to the geometry of the diffusion region. The Poynting flux, dominated by Hall electric and magnetic fields created by differential ion and electron motion is surprisingly large. This has significant implications for our understanding of reconnection energetics, because this signal propagates away from the reconnection site at speeds significantly greater than the Alfven speed.

  15. Micro\\/nanofluidics-enabled energy conversion and its implemented devices

    Microsoft Academic Search

    Yang Yang; Jing Liu

    Most people were not aware of the role of energy as a basic force that drives the development and economic growth of the world\\u000a until the two great oil crises occurred. According to the conservation law, energy not only exists in various forms but is\\u000a also capable of being converted from one form to another. The common forms of energy

  16. Efficient conversion of solar energy to biomass and electricity.

    PubMed

    Parlevliet, David; Moheimani, Navid Reza

    2014-01-01

    The Earth receives around 1000 W.m(-2) of power from the Sun and only a fraction of this light energy is able to be converted to biomass (chemical energy) via the process of photosynthesis. Out of all photosynthetic organisms, microalgae, due to their fast growth rates and their ability to grow on non-arable land using saline water, have been identified as potential source of raw material for chemical energy production. Electrical energy can also be produced from this same solar resource via the use of photovoltaic modules. In this work we propose a novel method of combining both of these energy production processes to make full utilisation of the solar spectrum and increase the productivity of light-limited microalgae systems. These two methods of energy production would appear to compete for use of the same energy resource (sunlight) to produce either chemical or electrical energy. However, some groups of microalgae (i.e. Chlorophyta) only require the blue and red portions of the spectrum whereas photovoltaic devices can absorb strongly over the full range of visible light. This suggests that a combination of the two energy production systems would allow for a full utilization of the solar spectrum allowing both the production of chemical and electrical energy from the one facility making efficient use of available land and solar energy. In this work we propose to introduce a filter above the algae culture to modify the spectrum of light received by the algae and redirect parts of the spectrum to generate electricity. The electrical energy generated by this approach can then be directed to running ancillary systems or producing extra illumination for the growth of microalgae. We have modelled an approach whereby the productivity of light-limited microalgae systems can be improved by at least 4% through using an LED array to increase the total amount of illumination on the microalgae culture. PMID:24976951

  17. Ultrahigh Energy Neutrals from Extreme Magnetic Flares

    E-print Network

    David Eichler

    2003-03-20

    It is shown that bulk acceleration during reconnection of extremely strong magnetic fields near compact objects can accelerate ions to Lorentz factors of $\\sim 10^2 \\sigma^{3/5}$ under general conditions, where $\\sigma$, the magnetic energy per current-carrying proton rest energy, can approach $10^{15}$. For magnetar-type fields, neutrons and neutrinos can be generated at potentially detectable levels via hadron polarization. Ultrahigh energy photons can also be emitted and escorted from the high field region by Poynting flux.

  18. Magnetic field topology and energy release sites

    E-print Network

    University College London

    low velocities (~0.1 kms-1) line tying and the reverse. and the reverse. Jacobian matrix: Initial QSL in the connectivity of its field lines. By this change free magnetic energy is released and converted into heat and kinetic energy of the plasma. Small spatial scales should be present for reconnection to be efficient

  19. New power-conditioning systems for superconducting magnetic energy storage

    NASA Astrophysics Data System (ADS)

    Han, Byung Moon

    1992-06-01

    This dissertation presents the development of new power-conditioning systems for superconducting magnetic energy storage (SMES), which can regulate fast and independently the active and reactive powers demanded in the ac network. Three new power-conditioning systems were developed through a systematic approach to match the requirements of the superconducting coil and the ac power network. Each of these new systems is composed of ten 100-MW modules connected in parallel to handle the large current through the superconducting coil. The first system, which was published in the IEEE Transactions on Energy Conversion, consists of line-commutated 24-pulse converter, a thyristor-switched tap-changing transformer, and a thyristor-switched capacitor bank. The second system, which was accepted for publication in the IEEE Transactions on Energy Conversion, consists of a 12-pulse GTO (gate turn-off thyristor) converter and a thyristor-switched tap-changing transformer. The third system, which was submitted to the International Journal of Energy System, consists of a dc chopper and a voltage-source PWM (pulse width modulation) converter. The operational concept of each new system is verified through mathematical analyses and computer simulations. The dynamic interaction of each new system with the ac network and the superconducting coil is analyzed using a simulation model with EMTP (electro-magnetic transients program). The analysis results prove that each new system is feasible and realizable. Each system can regulate the active and reactive powers of the utility network rapidly and independently, and each offer a significant reduction of the system rating by reducing the reactive power demand in the converter. Feasible design for each new system was introduced using a modular design approach based on the 1000 MW/5000 MWH plant, incorporating commercially available components and proven technologies.

  20. New power-conditioning systems for superconducting magnetic energy storage

    SciTech Connect

    Han, B.M.

    1992-01-01

    This dissertation presents the development of new power-conditioning systems for superconducting magnetic energy storage (SMES), which can regulate fast and independently the active and reactive powers demanded in the ac network. Three new power-conditioning systems were developed through a systematic approach to match the requirements of the superconducting coil and the ac power network. Each of these new systems is composed of ten 100-MW modules connected in parallel to handle the large current through the superconducting coil. The first system, which was published in the IEEE Transactions on EnergyConversion, consists of line-commutated 24-pulse converter, a thyristor-switched tap-changing transformer, and a thyristor-switched capacitor bank. The second system, which was accepted for publication in the IEEE Transactions on Energy Conversion, consists of a 12-pulse GTO (gate turn-off thyristor) converter and a thyristor-switched tap-changing transformer. The third system, which was submitted to the International Journal of Energy System, consists of a dc chopper and a voltage-source PWM (pulse width modulation) converter. The operational concept of each new system is verified through mathematical analyses and computer simulations. The dynamic interaction of each new system with the ac network and the superconducting coil is analyzed using a simulation model with EMTP (electro-magnetic transients program). The analysis results prove that each new system is feasible and realizable. Each system can regulate the active and reactive powers of the utility network rapidly and independently, and each offer a significant reduction of the system rating by reducing the reactive power demand in the converter. Feasible design for each new system was introduced using a modular design approach based on the 1000 MW/5000 MWH plant, incorporating commercially available components and proven technologies.

  1. Assessment of dynamic energy conversion systems for radioisotope heat sources

    NASA Astrophysics Data System (ADS)

    Thayer, G. R.; Mangeng, C. A.

    1985-06-01

    The use of dynamic conversion systems to convert the heat generated in a 7500 W(t) 90 Sr radioisotopic heat source to electricity is examined. The systems studies were: Stirling; Brayton cycle; three organic Rankines (ORCs) (Barber-Nichols/ORMAT, Sundstrand, and TRW); and an organic Rankine plus thermoelectrics. The systems were ranked for a North Warning System mission using a Los Alamos multiattribute decision theory code. Three different heat source designs were used: case 1 with a beginning of life (BOL) source temperature of 640 C, case 2 with a BOL source temperature of 745 C, and case 3 with a BOL source temperature of 945 C. The Stirling engine system was the top-ranked system of case 1 and 2, closely followed by the ORC systems in case 1 and ORC plus thermoelectrics in case 2. The Brayton cycle system was top-ranked for case 3, with the Stirling engine system a close second. The use of (238) Pu in heat source sizes of 7500 W(t) is examined and it is found to be questionable because of cost and material availability and because of additional requirements for anlaysis of safeguards and critical mass.

  2. Ocean based solar-to-hydrogen energy conversion macro system

    Microsoft Academic Search

    W. J. D. Escher; J. A. Hanson

    1975-01-01

    Mechanized ocean thermal power production of hydrogen fuel is investigated. Hydrogen's natural advantages of transportability and storability are the basis for the choice of this energy carrier over electricity. World production of fossil fuels is expected to peak between 2030 and 2080, at which time reliable and economic nonfossil-based energy supplies will be available. Ocean basing of large-scale 'central' solar

  3. High Efficiency Energy Conversion Systems for Liquid Nitrogen Automobiles

    E-print Network

    Laughlin, Robert B.

    -hr/kg for gasoline combusted in an engine running at 28% thermal efficiency. Lead-acid batteries can take hours, the battery-powered electric vehicle is the only commercially available technology that can meet ZEV standards energy storage, particularly lead-acid and Ni-Cd batteries. These heavy metal energy storage systems

  4. Bulk single crystal ternary substrates for a thermophotovoltaic energy conversion system

    DOEpatents

    Charache, G.W.; Baldasaro, P.F.; Nichols, G.J.

    1998-06-23

    A thermophotovoltaic energy conversion device and a method for making the device are disclosed. The device includes a substrate formed from a bulk single crystal material having a bandgap (E{sub g}) of 0.4 eV < E{sub g} < 0.7 eV and an emitter fabricated on the substrate formed from one of a p-type or an n-type material. Another thermophotovoltaic energy conversion device includes a host substrate formed from a bulk single crystal material and lattice-matched ternary or quaternary III-V semiconductor active layers. 12 figs.

  5. Cogeneration Technology Alternatives Study (CTAS). Volume 3: Energy conversion system characteristics

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Six current and thirty-six advanced energy conversion systems were defined and combined with appropriate balance of plant equipment. Twenty-six industrial processes were selected from among the high energy consuming industries to serve as a frame work for the study. Each conversion system was analyzed as a cogenerator with each industrial plant. Fuel consumption, costs, and environmental intrusion were evaluated and compared to corresponding traditional values. The advanced energy conversion technologies indicated reduced fuel consumption, costs, and emissions. Fuel energy savings of 10 to 25 percent were predicted compared to traditional on site furnaces and utility electricity. With the variety of industrial requirements, each advanced technology had attractive applications. Fuel cells indicated the greatest fuel energy savings and emission reductions. Gas turbines and combined cycles indicated high overall annual savings. Steam turbines and gas turbines produced high estimated returns. In some applications, diesels were most efficient. The advanced technologies used coal derived fuels, or coal with advanced fluid bed combustion or on site gasifications. Data and information for both current and advanced energy conversion technology are presented. Schematic and physical descriptions, performance data, equipment cost estimates, and predicted emissions are included. Technical developments which are needed to achieve commercialization in the 1985-2000 period are identified.

  6. Relativistic fireballs - Energy conversion and time-scales

    NASA Technical Reports Server (NTRS)

    Rees, M. J.; Meszaros, P.

    1992-01-01

    The expansion energy of a relativistic fireball can be reconverted into radiation when it interacts with an external medium. For expansion with Lorentz factors greater than or approximately equal to 1000 into a typical galactic environment, the corresponding time-scale in the frame of the observer is of the order of seconds. This mechanism would operate in any cosmological scenario of gamma-ray bursts involving initial energies of order a percent of a stellar rest mass, and implies photon energies and time-scales compatible with those observed in gamma-ray bursts.

  7. Magnets for high energy colliders

    SciTech Connect

    Spencer, J.; Stucki, H.

    1989-03-01

    The problem of producing, preserving and stably colliding low emittance bunches for long periods of time is a formidable problem involving questions of jitter, dynamic alignment and reproducibility associated with magnetic and mechanically hysteresis. Permanent magnets provide ideal solutions for lower capital and operating costs. Because they are light in weight, compact and require no power or cooling they are easy to use, stable and uniquely reliable. With their low permeability this implies a minimal impact on the surrounding environment and vice versa. For example, they are ideal for final focus systems embedded in particle detectors with strong solenoidal fields while their strength and compactness minimizes the solid angle they subtend around the interaction point (IP) as well as their target thickness along the beam line. We discuss calculations there /rvec B/ is a nonlinear, anisotropic function of /rvec H/. The results explain discrepancies observed measurement and calculation of permanent magnet systems and indicate good multipoles are possible with far higher strengths than previously obtained. We extend previous calculations on the obtainable gradients for different types of quadrupoles down to 1 mm bore radii where 2000 T/m appears possible with conventional designs and available materials. We discuss why much higher gradients are possible by the same means. Additional specifications for PM manufacturers are recommended. 14 refs., 5 figs.

  8. Ionosphere/microwave beam interaction study. [satellite solar energy conversion

    NASA Technical Reports Server (NTRS)

    Duncan, L. M.; Gordon, W. E.

    1977-01-01

    A solar power satellite microwave power density of 20mw sq cm was confirmed as the level where nonlinear interactions may occur in the ionosphere, particularly at 100 km altitude. Radio wave heating at this altitude, produced at the Arecibo Observatory, yielded negative results for radio wave heating of an underdense ionosphere. Overdense heating produced striations in the ionosphere which may cause severe radio frequency interference problems under certain conditions. The effects of thermal self-focusing are shown to be limited severely geographically. The aspect sensitivity of field-aligned striations makes interference-free regions above magnetic latitude about 60 deg. A test program is proposed to simulate the interaction of the SPS beam with the ionosphere, to measure the effects of the interaction on the ionosphere and on communication and navigation systems, and to interpret the results.

  9. Multi-energy conversion of Gd5 (Si2Ge2)-poly (vinylidene fluoride), a hybrid material

    NASA Astrophysics Data System (ADS)

    Ozaydin, M. F.; Liang, H.

    2014-08-01

    A class of multiphase composites is reported here. These composites consist of magnetocaloric Gd5Si2Ge2 (GSG) particles embedded in a polyvinylidene fluoride (PVDF) matrix. Under an external magnetic field, those materials were found to generate an electrical voltage up to 0.11 V, equivalent to the power density of 14.3 mW/cm3 Oe when the concentration of Gd5Si2Ge2 was at 4 wt. %. This was due to the magnet-induced strain in Gd5Si2Ge2 leading to the voltage generation in the piezoelectric polymer. The power density of the hybrid system has proven to be significantly higher than each single phase alone. When tested individually PVDF has a power density of 3.25 mW/cm3 Oe and Gd5Si2Ge2 has 0 power output. The coupling of magnetic and piezoelectric effects enables multi-energy conversion that is unique for device design and clean energy harvesting.

  10. A review of impulse turbines for wave energy conversion

    Microsoft Academic Search

    T Setoguchi; S Santhakumar; H Maeda; M Takao; K Kaneko

    2001-01-01

    Oscillating Water Column based wave energy plants convert wave energy into low pressure pnuematic power in the form of bi-directional air flows. Air turbines which are capable of rotating uni-directionally in bi-directional air flow, otherwise also known as self-rectifying turbines, are used to extract mechanical shaft power which is further converted into electrical power by a generator. This paper reviews

  11. Optimization of Reaction Plates for Wave Energy Conversion

    NASA Astrophysics Data System (ADS)

    Brown, A. C.

    2014-12-01

    Reaction forces are generated as energy is extracted from the motion of ocean waves relative to a wave energy converter (WEC). The reaction forces effect the momentum of the WEC, and in most cases it is beneficial to transfer the loads to a relatively stationary external body. It has become common for WECs to include reaction plates that use hydrodynamic damping to transfer the loads developed during energy extraction to the relatively stationary water below the surface of the ocean. Reaction plates allow WECs to use compliant moorings, which reduce mooring loads and are more easily deployed than taut moorings. Heave plates are commonly used on offshore platforms, but the design of reaction plates for wave energy converters has received little attention. This work presents an initial optimization of reaction plate form to improve the heave and surge performance of the WEC reference models developed for the US Department of Energy. The benefits and drawbacks of various reaction plate geometries are compared, and the impacts on WEC stability, peak loading, and energy production are considered.

  12. High efficiency beta radioisotope energy conversion using reciprocating electromechanical converters with integrated betavoltaics

    Microsoft Academic Search

    Rajesh Duggirala; Hui Li; Amit Lal

    2008-01-01

    We demonstrate a 5.1% energy conversion efficiency 63Ni radioisotope power generator by integrating silicon betavoltaic converters with radioisotope actuated reciprocating piezoelectric unimorph cantilever converters. The electromechanical energy converter efficiently utilizes both the kinetic energy and the electrical charge of the 0.94 muW beta radiation from a 9 mCi 63Ni thin film source to generate maximum (1) continuous betavoltaic electrical power

  13. Isothermal separation processes update. Energy Conversion and Utilization Technologies Program

    SciTech Connect

    England, C.

    1984-08-01

    The isothermal processes of membrane separation, supercritical extraction and condensed-phase chromatography were examined using availability analysis, a method which addresses the thermodynamic value of energy as well as its amount. The general approach was to derive equations that identified where energy, expressed in terms of thermodynamic work, is consumed in these processes and how they compare with conventional separation methods. These separation methods are characterized by pure work inputs, chiefly in the form of a pressure drop which supplies the required energy. Equations were derived for the energy requirement in terms of the theories of ideal and regular solutions. This approach is believed to accurately predict the work of separation in terms of the heat of solution and the entropy of mixing. It can form the basis of a convenient calculation method for optimizing membrane and solvent properties for particular applications. Close examination of supercritical extraction found a relatively simple thermodynamic relationship among the thermodynamic properties of the solvent, the entropy of mixing, and the heat of solution. This allows a direct estimate of the work requirements. The actual work, however, is largely due to the requirement to cycle pressure at high levels in this method. Still, the energy requirements are very low, making up for usually high capital costs for equipment. 12 references, 9 figures, 2 tables.

  14. IECEC '91; Proceedings of the 26th Intersociety Energy Conversion Engineering Conference, Boston, MA, Aug. 4-9, 1991. Vol. 3 - Conversion technologies, electrochemical conversion

    NASA Astrophysics Data System (ADS)

    The present volume on energy conversion engineering discusses MHD, thermionics, thermoelectrics, aerospace batteries, batteries for secondary and terrestrial applications, and field cells for space and terrestrial applications. Attention is given to the economics of MHD retrofits and new plants, a prototypic MHD generator design of the integrated topping cycle power train, MHD plant turn-down considerations, a simulation of normal and oblique shock waves in an MHD channel, and the stability of MHD plasmas ionized by nuclear fragments. Topics addressed include the prediction of the start-up characteristics of a heat pipe-cooled thermionic fuel element (TFE), a TFE sheath insulator in-reactor test design, a TFE verification program overview, and coupled thermionic and thermalhydraulic analyses of thermionic fuel elements. Also discussed are the possibilities of using alternative fuels in a thermionic fuel element, a comparison of nickel-hydrogen and nickel-cadmium reliability, a battery performance simulation for the Magellan mission, and a study of rechargeable lithium cells for space applications.

  15. Conversion of visible light to electrical energy - Stable cadmium selenide photoelectrodes in aqueous electrolytes

    NASA Technical Reports Server (NTRS)

    Wrighton, M. S.; Ellis, A. B.; Kaiser, S. W.

    1977-01-01

    Stabilization of n-type CdSe to photoanodic dissolution is reported. The stabilization is accomplished by the competitive oxidation of S(--) or S(n)(--) at the CdSe photoanode in an electrochemical cell. Such stabilized cells are shown to sustain the conversion of low energy (not less than 1.7 eV) visible light to electricity with good efficiency and no deterioration of the CdSe photoelectrode or of the electrolyte. The electrolyte undergoes no net chemical change because the oxidation occurring at the photoelectrode is reversed at the cathode. Conversion of monochromatic light at 633 nm to electricity is shown to be up to approximately 9% efficient with output potentials of approximately 0.4 V. Conversion of solar energy to electricity is estimated to be approximately 2% efficient.

  16. Conducting polymer soft actuators based on polypyrrole films—energy conversion efficiency

    NASA Astrophysics Data System (ADS)

    Kaneto, Keiichi; Fujisue, Hisashi; Kunifusa, Masakatsu; Takashima, Wataru

    2007-04-01

    The electrochemomechanical deformation (ECMD) of conducting polymers can be used to create soft actuators or transducers for the conversion of electric power to mechanical work. Polypyrrole (PPy) films, which were electrodeposited from a methyl benzoate solution of tetrabutylammonium (TBA) trifluoromethansulfonate, TBACF3SO3, were used to investigate the energy conversion efficiency. The films are known to have high tensile strength and to produce large strain at high stress in ECMD. The current as a function of load stress under constant applied potentials versus a reference electrode was studied in various electrolytes. Reduction currents increased with increasing load stress for contraction of the film (lifting weights) as well as for the oxidation current (expansion), indicating that the electrical input was sensing the load hung on the actuators. During the contraction, the conversion efficiency was estimated from the mechanical work energy. The maximum work energy-per-cycle was 140 kJ m-3. It has been found that the energy conversion efficiencies are very small (<0.25%). Most of the input electrical energy is stored electrochemically, but a significant fraction is also dissipated.

  17. One-dimension-based spatially ordered architectures for solar energy conversion.

    PubMed

    Liu, Siqi; Tang, Zi-Rong; Sun, Yugang; Colmenares, Juan Carlos; Xu, Yi-Jun

    2015-08-01

    The severe consequences of fossil fuel consumption have resulted in a need for alternative sustainable sources of energy. Conversion and storage of solar energy via a renewable method, such as photocatalysis, holds great promise as such an alternative. One-dimensional (1D) nanostructures have gained attention in solar energy conversion because they have a long axis to absorb incident sunlight yet a short radial distance for separation of photogenerated charge carriers. In particular, well-ordered spatially high dimensional architectures based on 1D nanostructures with well-defined facets or anisotropic shapes offer an exciting opportunity for bridging the gap between 1D nanostructures and the micro and macro world, providing a platform for integration of nanostructures on a larger and more manageable scale into high-performance solar energy conversion applications. In this review, we focus on the progress of photocatalytic solar energy conversion over controlled one-dimension-based spatially ordered architecture hybrids. Assembly and classification of these novel architectures are summarized, and we discuss the opportunity and future direction of integration of 1D materials into high-dimensional, spatially organized architectures, with a perspective toward improved collective performance in various artificial photoredox applications. PMID:25856797

  18. Solar-to-Chemical Energy Conversion with Photoelectrochemical Tandem Cells.

    PubMed

    Sivula, Kevin

    2013-01-01

    Efficiently and inexpensively converting solar energy into chemical fuels is an important goal towards a sustainable energy economy. An integrated tandem cell approach could reasonably convert over 20% of the sun's energy directly into chemical fuels like H2 via water splitting. Many different systems have been investigated using various combinations of photovoltaic cells and photoelectrodes, but in order to be economically competitive with the production of H2 from fossil fuels, a practical water splitting tandem cell must optimize cost, longevity and performance. In this short review, the practical aspects of solar fuel production are considered from the perspective of a semiconductor-based tandem cell and the latest advances with a very promising technology - metal oxide photoelectrochemical tandem cells - are presented. PMID:23574955

  19. Mode Conversion and Energy Partitioning at Active Volcanoes

    Microsoft Academic Search

    M. Yamamoto; T. Nishimura; T. Tsutsui; M. Iguchi

    2010-01-01

    It has recently been shown that correlations of seismic noise and coda wave provide rich information on the Green's function between observation sites. Such technique, known as seismic interferometry, are often based on the assumption of equipartitioning, and thus the energy partitioning of diffuse waves has been widely studies from the view points of wave theory and experimental\\/field observations. Recently,

  20. Ocean Thermal Energy Conversion: Potential Environmental Impacts and Fisheries

    E-print Network

    Hawai'i at Manoa, University of

    , M.Sc. Candidate University of Hawaii at Manoa Department of Oceanography Hawaii Natural Energy distributions ­ Densities ­ Seasonal variability · Example: ­ Mesopelagic boundary community Benoit-Bird et al offshore of Oahu #12;Yellowfin Reproductive Biology · Spawning frequency ­ Hawaii: 1.02-1.24 days · Batch

  1. Wind Energy Conversion Systems Fault Diagnosis Using Wavelet Analysis

    E-print Network

    Paris-Sud XI, Université de

    , induction generator, Discrete Wavelet Transform (DWT), failure diagnosis. I. Introduction Wind energy voltage, current and power and are used to detect turn faults, broken rotor bars, bearing failures, air transient technique suitable for electrical and mechanical failure diagnosis in an induction generator based

  2. The role of latent heat in kinetic energy conversions of South Pacific cyclones

    NASA Technical Reports Server (NTRS)

    Kann, Deirdre M.; Vincent, Dayton G.

    1986-01-01

    The four-dimensional behavior of cyclone systems in the South Pacific Convergence Zone (SPCZ) is analyzed. Three cyclone systems, which occurred during the period from January 10-16, 1979, are examined using the data collected during the first special observing period of the FGGE. The effects of latent heating on the life cycles of the cyclones are investigated. Particular attention is given to the conversions of eddy available potential energy to eddy kinetic energy and of mean kinetic energy to eddy kinetic energy. The net radiation profile, sensible heat flux, total field of vertical motion, and latent heat component were computed. The life cycles of the cyclones are described. It is observed that the latent heating component accounts for nearly all the conversion in the three cyclones, and latent heating within the SPCZ is the major source of eddy kinetic energy for the cyclones.

  3. Magnetic Energy Storage in Coronal Active Regions

    NASA Astrophysics Data System (ADS)

    Wolfson, Richard; Drake, C.; Kennedy, M.

    2011-05-01

    We consider magnetic energy storage in a force-free coronal model that simulates an active region by superposing a strong, localized magnetic bipole on a global background dipole. As we found earlier for dipolar and quadrupolar boundary conditions, our solutions develop detached flux ropes, whose energy can exceed that of the corresponding open field; this excess energy is available to power eruptive events such as coronal mass ejections. Our earlier work, and that of others on related magnetic configurations, has generally yielded excess energies of at most approximately 25 percent of the corresponding potential-field energy. Our new active-region models greatly exceed that value, with stressed force-free fields whose energy excess above the open-field state can be well over 100 percent of the energy stored in the associated potential field. Moving the model active region poleward increases the maximum value of this excess stored energy. This work is funded by NSF grant AGS0940503 to Middlebury College.

  4. Thermoelectric Energy Conversion Technology for High-Altitude Airships

    NASA Technical Reports Server (NTRS)

    Choi, Sang H.; Elliott, James R.; King, Glen C.; Park, Yeonjoon; Kim, Jae-Woo; Chu, Sang-Hyon

    2011-01-01

    The High Altitude Airship (HAA) has various application potential and mission scenarios that require onboard energy harvesting and power distribution systems. The power technology for HAA maneuverability and mission-oriented applications must come from its surroundings, e.g. solar power. The energy harvesting system considered for HAA is based on the advanced thermoelectric (ATE) materials being developed at NASA Langley Research Center. The materials selected for ATE are silicon germanium (SiGe) and bismuth telluride (Bi2Te3), in multiple layers. The layered structure of the advanced TE materials is specifically engineered to provide maximum efficiency for the corresponding range of operational temperatures. For three layers of the advanced TE materials that operate at high, medium, and low temperatures, correspondingly in a tandem mode, the cascaded efficiency is estimated to be greater than 60 percent.

  5. Artificial light-harvesting arrays for solar energy conversion.

    PubMed

    Harriman, Anthony

    2015-07-01

    Solar fuel production, the process whereby an energy-rich substance is produced using electrons provided by water under exposure to sunlight, requires the cooperative accumulation of multiple numbers of photons. Identifying the optimum reagents is a difficult challenge, even without imposing the restriction that these same materials must function as both sensitiser and catalyst. The blockade caused by an inadequate supply of photons at the catalytic sites might be resolved by making use of an artificial light-harvesting array whose sole purpose is to funnel photons of appropriate frequency to the active catalyst, which can now be a dark reagent. Here we consider several types of artificial photon collectors built from fluorescent modules interconnected via electronic energy transfer. Emphasis is placed on the materials aspects and on establishing the basic operating principles. PMID:26086688

  6. Chemical Expansion: Implications for Electrochemical Energy Storage and Conversion Devices

    NASA Astrophysics Data System (ADS)

    Bishop, S. R.; Marrocchelli, D.; Chatzichristodoulou, C.; Perry, N. H.; Mogensen, M. B.; Tuller, H. L.; Wachsman, E. D.

    2014-07-01

    Many energy-related materials rely on the uptake and release of large quantities of ions, for example, Li+ in batteries, H+ in hydrogen storage materials, and O2- in solid-oxide fuel cell and related materials. These compositional changes often result in large volumetric dilation of the material, commonly referred to as chemical expansion. This article reviews the current knowledge of chemical expansion and aspires to facilitate and promote future research in this field by providing a taxonomy for its sources, along with recent atomistic insights of its origin, aided by recent computational modeling and an overview of factors impacting chemical expansion. We discuss the implications of chemical expansion for mechanical stability and functionality in the energy applications above, as well as in other oxide-based systems. The use of chemical expansion as a new means to probe other materials properties, as well as its contribution to recently investigated electromechanical coupling, is also highlighted.

  7. Free energy conversion in the LUCA: Quo vadis?

    PubMed

    Ducluzeau, Anne-Lise; Schoepp-Cothenet, Barbara; Baymann, Frauke; Russell, Michael J; Nitschke, Wolfgang

    2014-07-01

    Living entities are unimaginable without means to harvest free energy from the environment, that is, without bioenergetics. The quest to understand the bioenergetic ways of early life therefore is one of the crucial elements to understand the emergence of life on our planet. Over the last few years, several mutually exclusive scenarios for primordial bioenergetics have been put forward, all of which are based on some sort of empirical observation, a remarkable step forward from the previous, essentially untestable, ab initio models. We here try to present and compare these scenarios while at the same time discuss their respective empirical weaknesses. The goal of this article is to harness crucial new expertise from the entire field by stimulating a larger part of the bioenergetics community to become involved in "origin-of-energy-metabolism" research. This article is part of a Special Issue entitled: 18th European Bioenergetic Conference. PMID:24361840

  8. New approaches to photovoltaic and photoelectrochemical energy conversion

    NASA Astrophysics Data System (ADS)

    Shah, S. Ismat; Lin, Hong-Ying; Miao, Yinghong; Schulz, Meghan E.

    2008-04-01

    In response to skyrocketing fuel costs and evidence of climate change, real technological progress is needed towards harnessing the clean power from the sun to drive human progress. Here we present two approaches to harnessing solar energy currently under investigation in our group. One involves novel photovoltaic cells using different sized quantum dots. Another uses proven photocatalysts to directly electrolyze water, producing hydrogen. The technological background will be discussed, as well as current state of the art and future research direction.

  9. Application of a Ferroelectric Material in an Energy Conversion Device

    Microsoft Academic Search

    J. D. Childress

    1962-01-01

    The thermodielectric converter, a device employing a ferroelectric material as the active element in converting thermal to electrical energy, is analyzed. The efficiency and power-handling capacity are calculated for operation of a ferroelectric material in the induced-ferroelectric region on the basis of an idealization of the polarization (P-E) characteristics. The idealization includes the induced-ferroelectric transition but excludes hysteresis and other

  10. Micro Electret Energy Harvesting Device with Analogue Impedance Conversion Circuit

    Microsoft Academic Search

    Yuji Suzuki; Masato Edamoto; Nobuhide Kasagi; Kimiaki Kashiwagi; Yoshitomi Morizawa; Toru Yokoyama; Tomonori Seki; Masatoshi Oba

    2008-01-01

    A vibration-driven electret generator has been developed for energy harvesting applications. By using parylene as the spring material, a low-resonant-frequency MEMS generator is realized. Large in- plane amplitude of 0.8 mm at the resonant frequency as low as 37 Hz has been achieved. With our early prototype, output power of 0.28 ?W has been obtained. We also demonstrate electret-powered operation

  11. Advanced, High Power, Next Scale, Wave Energy Conversion Device

    SciTech Connect

    Mekhiche, Mike [Principal Investigator] [Principal Investigator; Dufera, Hiz [Project Manager] [Project Manager; Montagna, Deb [Business Point of Contact] [Business Point of Contact

    2012-10-29

    The project conducted under DOE contract DE?EE0002649 is defined as the Advanced, High Power, Next Scale, Wave Energy Converter. The overall project is split into a seven?stage, gated development program. The work conducted under the DOE contract is OPT Stage Gate III work and a portion of Stage Gate IV work of the seven stage product development process. The project effort includes Full Concept Design & Prototype Assembly Testing building on our existing PowerBuoy? technology to deliver a device with much increased power delivery. Scaling?up from 150kW to 500kW power generating capacity required changes in the PowerBuoy design that addressed cost reduction and mass manufacturing by implementing a Design for Manufacturing (DFM) approach. The design changes also focused on reducing PowerBuoy Installation, Operation and Maintenance (IO&M) costs which are essential to reducing the overall cost of energy. In this design, changes to the core PowerBuoy technology were implemented to increase capability and reduce both CAPEX and OPEX costs. OPT conceptually envisaged moving from a floating structure to a seabed structure. The design change from a floating structure to seabed structure would provide the implementation of stroke? unlimited Power Take?Off (PTO) which has a potential to provide significant power delivery improvement and transform the wave energy industry if proven feasible.

  12. Magnetic domain wall energy in Ni/Co superlattices

    NASA Astrophysics Data System (ADS)

    Toyoki, Kentaro; Nishimura, Takashi; Harimoto, Shotaro; Shiratsuchi, Yu; Nakatani, Ryoichi

    2014-12-01

    The magnetic domain wall energy density ?W of a Ni/Co superlattice possessing perpendicular magnetic anisotropy was determined using the magnetic domain theory derived by Kooy and Enz (1960). To determine ?W, we obtained the saturation magnetization, magnetic domain period, and perpendicular magnetic anisotropy energy by individual measurements. Using the magnetic domain period and the ferromagnetic layer thickness, we first determined the dipolar length. The estimated dipolar length was about 15-25 nm, which is in good agreement with the change in the magnetization curve with the ferromagnetic layer thickness. By using the dipolar length and saturation magnetization, the ?W was calculated to be 4-7 erg/cm2.

  13. Condition Monitoring and Fault Diagnosis in Wind Energy Conversion Systems: A Review

    E-print Network

    Paris-Sud XI, Université de

    for the reduction of operational and maintenance costs of Wind Energy Conversion Systems (WECS). The most efficient. This allows for early detection of the degeneration of the generator health, facilitating a proactive response actions to prevent damage of plants components. This way, overall maintenance costs and down times of wind

  14. TPV energy conversion: A review of material and cell related issues

    SciTech Connect

    Bhat, I.B.; Borrego, J.M.; Gutmann, R.J.; Ostrogorsky, A.G. [Rensselaer Polytechnic Inst., Troy, NY (United States). Center for Integrated Electronics and Electronic Manufacturing

    1996-08-01

    This paper presents an overview of thermophotovoltaic (TPV) energy conversion using low band gap semiconductor photovoltaic cells. Physics of PN junctions related to TPV cells is described and the factors that affect overall cell efficiencies are outlined. Current status of bulk and epitaxial growth of TPV materials and cell fabrication issues are also described.

  15. Kinematic Stirling engine as an energy conversion subsystem for paraboloidal dish solar thermal power plants

    Microsoft Academic Search

    1984-01-01

    The potential of a suitably designed and economically manufactured Stirling engine as the energy conversion subsystem of a paraboloidal dish-Stirling solar thermal power module has been estimated. Results obtained by elementary cycle analyses have been shown to match quite well the performance characteristics of an advanced kinematic Stirling engine, the United Stirling P-40, as established by current prototypes of the

  16. The kinematic Stirling engine as an energy conversion subsystem for paraboloidal dish solar thermal plants

    Microsoft Academic Search

    J. M. Bowyer

    1984-01-01

    The potential of a suitably designed and economically manufactured Stirling engine as the energy conversion subsystem of a paraboloidal dish-Stirling solar thermal power module was estimated. Results obtained by elementary cycle analyses were shown to match quite well the performance characteristics of an advanced kinematic Stirling engine, the United Stirling P-40, as established by current prototypes of the engine and

  17. Rep-rated Z-Pinch Power Plant Concept - Direct Energy Conversion and Shrapnel Generation

    Microsoft Academic Search

    John S. de Groot; Niels Gronbech-Jensen; Greg Miller; Craig L. Olsen; Gary E. Rochau; Mark S. Derzon; Steven A. Slutz; Rick B. Spielman; Per F. Peterson; Gregory A. Rochau; Robert R. Pederson

    2000-01-01

    We are developing direct energy conversion schemes and shrapnel generation models to be used to optimize a high yield z-pinch IFE power plant concept. The concept uses high yield ( 10 GJ) at low rep-rate ( 0.1 Hz), with a Recyclable Transmission Line (RTL) to provide the necessary standoff between the fusion target and the power plant chamber. The RTL

  18. Current status of self rectifying air turbines for wave energy conversion

    Microsoft Academic Search

    Toshiaki Setoguchi; Manabu Takao

    2006-01-01

    This paper reviews the present state of the art on self rectifying air turbines, which could be used for wave energy conversion. The overall performances of the turbines under irregular wave conditions, which typically occur in the sea, have been evaluated numerically and compared from the viewpoints of their starting and running characteristics. The types of turbine included in the

  19. A simulation analysis of double-fed induction generator for wind energy conversion using PSpice

    Microsoft Academic Search

    Shuhui Li; Sitanshu Sinha

    2006-01-01

    A wind energy conversion system (WECS) differs from a conventional power system. In a conventional power plant, the power generation can be controlled. But, the power output of a WECS fluctuates with the wind. This variable power generation nature makes it difficult for analysis, design, and management of a WECS so that various approaches have been developed to study WECS

  20. Flexible retractable cold water pipe for an ocean thermal energy conversion system

    Microsoft Academic Search

    J. G. Wenzel; L. C. Trimble

    1985-01-01

    A cold water pipe for an ocean thermal energy conversion (OTEC) system comprises a tubular membrane made of a fabric such as a canvas, which is substantially impervious to flowing water. A proximal end of the pipe is secured to a surface structure such as a ship, and a distal end of the pipe is extendible from the surface structure

  1. Conversion of thermal energy into electricity via a water pump operating in Stirling engine cycle

    Microsoft Academic Search

    V. S. Slavin; G. C. Bakos; K. A. Finnikov

    2009-01-01

    In this paper, the principle of heat energy conversion via Stirling pump into electricity is considered. New scheme of Stirling pump is proposed, that differs from known ones in application of offset heater and cooler and valves controlling the motion of liquid. The mathematical model is implemented to examine the liquid flow and gas heat exchange in cylinders and regenerator.

  2. Short-term memory-based control of wind energy conversion systems

    Microsoft Academic Search

    Xiao-Yan Mei; Zhao Sun; Bin Li; Zhi Yang; Yong D. Song

    2006-01-01

    Variable speed wind turbine control is essential in extracting maximum electric power out of available wind power. The paper presents a memory-based method for variable speed control of wind energy conversion systems. The fundamental idea behind the method is to use certain memorized information (i.e., current rotor speed tracking error, most recent speed tracking error, and previous control experience) to

  3. Dynamical mechanism for the conversion of energy at a molecular scale Naoko Nakagawa

    E-print Network

    Kaneko, Kunihiko

    and Applied Sciences, College of Arts and Sciences, University of Tokyo, Tokyo 153-8902, Japan Received 15- lecular motors 3 . This loose coupling mechanism is ex- pected to work under fluctuations of a comparable hand, the energy conversion seems to proceed even by a single event of exci- tation of a motor protein

  4. Control of a Wind Energy Conversion System with active filtering function

    Microsoft Academic Search

    T. Mesbahi; T. Ghennam; E. M. Berkouk

    2011-01-01

    This paper presents a proposed control of a Wind Energy Conversion System (WECS) with active filtering function for non linear conditions. The Rotor Side Converter (RSC) controls the active and reactive power injected to the grid by the stator of the Doubly Fed Induction Generator (DFIG).The specified control of the Grid Side Converter (GSC) ensures simultaneously the DC link voltage

  5. Methods of Measuring Energy Conversion Efficiency in Dye-sensitized Solar Cells

    Microsoft Academic Search

    Naoki Koide; Yasuo Chiba; Liyuan Han

    2005-01-01

    The current-voltage characteristics of dye-sensitized solar cells (DSCs) were measured and compared with those of crystalline silicon solar cells. It was found that the energy conversion efficiency of DSCs is dependent on voltage sweep direction and sampling delay time (Td). Measurement of the transient photocurrent revealed that this dependence is due to the longer time constant of DSCs. This dependence

  6. A relaxation-based heuristic for the design of cost-effective energy conversion systems

    Microsoft Academic Search

    T. Ahadi-Oskui; H. Alperin; I. Nowak; F. Cziesla; G. Tsatsaronis

    2006-01-01

    Mathematicians and engineers have developed in a joint research project a solution approach for performing simultaneous structural and design variable optimization in the design of cost-effective complex energy conversion systems. The paper presents a methodology and an application to the design of a combined-cycle power plant that provides fixed amounts of electricity and steam for a paper factory. A superstructure

  7. Influences of external factors on the energy conversion and productivity of Scenedesmus sp. in mass culture

    Microsoft Academic Search

    J. C. Wesselius

    1973-01-01

    Experiments about the influence of external factors on the energy conversion in mass cultures of Scenedesmus are described in this thesis. Several types of culture vessels were used in the laboratory as well as in the open. Demonstration models of Miele washing machines with a volume of 50 l were used for experiments in the open. In the laboratory the

  8. Stresa, Italy, 26-28 April 2006 ENERGY CONVERSION USING NEW THERMOELECTRIC GENERATOR

    E-print Network

    Paris-Sud XI, Université de

    Stresa, Italy, 26-28 April 2006 ENERGY CONVERSION USING NEW THERMOELECTRIC GENERATOR G. Savelli1. It appears that many of these technologies can be applied successfully to realize Seebeck micro generators: photolithography and deposition methods allow to elaborate thin thermoelectric structures at the micro-scale level

  9. Conversion of unused heat energy to electricity by means of thermoelectric generation in condenser

    Microsoft Academic Search

    Takashi Kyono; Ryosuke O. Suzuki; Katsutoshi Ono

    2003-01-01

    Thermoelectric power generation has the potential to recover a large amount of energy loss at the vapor condensers in the steam-based power plants. A suitable arrangement of thermoelectric modules was designed from the heat transfer theory in the cylindrical heat exchanger. Even under the practical operation limits, 150 kW can be generated by the thermoelectric conversion.

  10. ENVIRONMENTAL AND ECONOMIC COMPARISON OF ADVANCED PROCESSES FOR CONVERSION OF COAL AND BIOMASS INTO CLEAN ENERGY

    EPA Science Inventory

    Biomass and coal conversion into clean energy is compared on an economic and environmental basis in three regional scenarios: (1) electric power from direct combustion of wood versus conventional coal combustion in the South Central U.S., (2) synthetic pipeline gas from anaerobic...

  11. Technical evaluation of Aerojet Energy Conversion Company's topical report on a mobile volume reduction system

    SciTech Connect

    Henscheid, J.W.

    1984-10-25

    This report summarizes EG and G Idaho's review of Aerojet Energy Conversion Company's (AECC's) topical report on a Mobile Volume Reduction System. The review evaluated compliance with pertinent codes, standards and regulations. The initial review was discussed with AECC by EG and G Idaho and the NRC, and all outstanding issues resolved before this final evaluation was made.

  12. Technical evaluation of Aerojet Energy Conversion Company's topical report on a mobile volume reduction system

    Microsoft Academic Search

    Henscheid

    1984-01-01

    This report summarizes EG and G Idaho's review of Aerojet Energy Conversion Company's (AECC's) topical report on a Mobile Volume Reduction System. The review evaluated compliance with pertinent codes, standards and regulations. The initial review was discussed with AECC by EG and G Idaho and the NRC, and all outstanding issues resolved before this final evaluation was made.

  13. Monte Carlo simulation of solid-state thermionic energy conversion devices based on non-planar

    E-print Network

    Monte Carlo simulation of solid-state thermionic energy conversion devices based on non structures is analyzed using a Monte Carlo electron transport model. Compared to the planar structures, about a chance to pass over the barrier in a triangle region. 2 Monte Carlo Algorithms We used a simplified

  14. 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.

  15. Optimize out-of-core thermionic energy conversion for nuclear electric propulsion

    NASA Technical Reports Server (NTRS)

    Morris, J. F.

    1977-01-01

    Current designs for out of core thermionic energy conversion (TEC) to power nuclear electric propulsion (NEP) were evaluated. Approaches to improve out of core TEC are emphasized and probabilities for success are indicated. TEC gains are available with higher emitter temperatures and greater power densities. Good potentialities for accommodating external high temperature, high power density TEC with heat pipe cooled reactors exist.

  16. Magnetic structure and domain conversion of the quasi-2D frustrated antiferromagnet CuCrO2 probed by NMR

    NASA Astrophysics Data System (ADS)

    Sakhratov, Yu. A.; Svistov, L. E.; Kuhns, P. L.; Zhou, H. D.; Reyes, A. P.

    2014-11-01

    We have carried out 63,65Cu NMR spectra measurements in a magnetic field up to about 15.5 T on a single crystal of the multiferroic triangular-lattice antiferromagnet CuCrO2. The measurements were performed for perpendicular and parallel orientations of the magnetic field with respect to the c axis of the crystal, and the detailed angle dependence of the spectra on the magnetic field direction in the ab plane was studied. The shape of the spectra can be well described in the model of spiral spin structure proposed by recent neutron diffraction experiments. When the field is rotated perpendicular to the crystal c axis, we observed, directly for the first time, a remarkable reorientation of the spin plane simultaneous with rotation of the incommensurate wavevector, by quantitatively deducing the conversion of the energetically less favorable domain to a more favorable one. At high enough fields parallel to the c axis, the data are consistent with either a field-induced commensurate spiral magnetic structure or an incommensurate spiral magnetic structure with a disorder in the c direction, suggesting that high fields may have influence on interplanar ordering.

  17. Application of Magnetic Energy Recovery Switch (MERS) to Improve Output Power of Wind Turbine Generators

    NASA Astrophysics Data System (ADS)

    Takaku, Taku; Homma, Gen; Isobe, Takanori; Kato, Shuhei; Igarashi, Seiki; Uchida, Yoshiyuki; Shimada, Ryuichi

    The experimental results of an innovative power conversion technology using magnetic energy recovery switch (MERS) in a wind turbine system with a synchronous generator to improve the output power and the efficiency are presented. The MERS can compensate for the reactance voltage of the generator. The output voltage of the system increases and the excitation power of the generator can be significantly reduced. The data indicate a great potential of the new power conversion technology to make the actual wind turbine system compact and to improve the efficiency.

  18. New energy conversion techniques in space, applicable to propulsion

    NASA Technical Reports Server (NTRS)

    Hertzberg, A.; Sun, K. C.

    1989-01-01

    The powering of aircraft with laser energy from a solar power satellite may be a promising new approach to the critical problem of the rising cost of fuel for aircraft transportation systems. The result is a nearly fuelless, pollution-free flight transportation system which is cost-competitive with the fuel-conservative airplane of the future. The major components of this flight system include a laser power satellite, relay satellites, laser-powered turbofans and a conventional airframe. The relay satellites are orbiting optical systems which intercept the beam from a power satellite and refocus and redirect the beam to its next target.

  19. Toroidal constant-tension superconducting magnetic energy storage units

    DOEpatents

    Herring, J. Stephen (Idaho Falls, ID)

    1992-01-01

    A superconducting magnetic energy storage unit is provided in which the magnet is wound in a toroidal fashion such that the magnetic field produced is contained only within the bore of the magnet, and thus producing a very low external field. The superconducting magnet includes a coolant channel disposed through the wire. The bore of the magnet comprises a storage volume in which cryogenic coolant is stored, and this volume supplies the coolant to be delivered to the coolant channel in the magnet.

  20. Flywheel energy storage. II - Magnetically suspended superflywheel

    NASA Technical Reports Server (NTRS)

    Kirk, J. A.; Studer, P. A.

    1977-01-01

    This article, the second of a two part paper, describes the general design requirements for a flywheel energy storage system. A new superflywheel energy storage system, using a spokeless, magnetically suspended, composite material pierced disk rotor is proposed. The new system is configured around a permanent magnet ('flux biased') magnetic suspension system with active control in the radial direction and passive control in the axial direction. The storage ring is used as a moving rotor and electronic commutation of stationary armature coils is proposed. There is no mechanical contact with the rotating ring and long life and low run down losses are projected. A discussion of major components for a 10 kwh system is presented.

  1. Twisted Savonius turbine based marine current energy conversion system

    NASA Astrophysics Data System (ADS)

    Hassan, Md. Imtiaj

    The Ocean Network Seafloor Instrumentation (ONSFI) Project is a multidisciplinary research and development project that aims to design, fabricate and validate a proof-of-concept seafloor array of wireless marine sensors for use in monitoring seabed processes. The sensor pods, known as Seaformatics, will be powered by ocean bottom currents and will be able to communicate with each other and to the Internet through surface master units to facilitate observation of the ocean floor from the shore. This thesis explores the use of the twisted Savonius turbine as a means of converting the kinetic energy of the free flowing water into electrical energy for the pods. This will eliminate the need for battery replacement. A physical model of the turbine was constructed and tested in the Water Flume at the Marine Institute of Memorial University and in the Wind Tunnel in the Engineering Building at Memorial University. A mathematical model of the turbine was constructed in SolidWorks. This was tested in the Computational Fluid Dynamics or CFD software FLOW-3D. Experimental results were compared with CFD results and the agreement was reasonable. A twisted Savonius turbine emulator was developed to test a dc-dc boost converter. A low cost microcontroller based MPPT algorithm was developed to obtain maximum power from the turbine. Overall the thesis shows that the twisted Savonius turbine can provide the power needed by the sensor pods. It also shows that CFD is a viable way to study the performance of the Savonius type of turbine.

  2. Combined chemical looping for energy storage and conversion

    NASA Astrophysics Data System (ADS)

    Galvita, Vladimir V.; Poelman, Hilde; Marin, Guy B.

    2015-07-01

    Combined chemical looping was demonstrated as novel concept of energy storage in a laboratory scale test. The proposed technology is able to store and release energy from redox chemical looping reactions combined with calcium looping. This process uses Fe3O4 and CaO, two low cost and environmentally friendly materials, while CH4 + CO2 serve as feed. During the reduction of Fe3O4 by CH4, both formation of carbon and metallic iron occur. CO2 acts as mediation gas to facilitate the metal/metal oxide redox reaction and carbon gasification into CO. CaO, on the other hand, is used for storage of CO2. Upon temperature rise, CaCO3 releases CO2, which re-oxidizes the carbon deposits and reduced Fe, thus producing carbon monoxide. The amount of produced CO is higher than the theoretical amount for Fe3O4, because carbon deposits from CH4 equally contribute to the CO yield. After each redox cycle, the material is regenerated, so that it can be used repeatedly, providing a stable process.

  3. An Experimental Study on Energy Conversion Process of an in-Space CW Laser Thruster

    SciTech Connect

    Uehara, Susumu; Inoue, Takayoshi; Komurasaki, Kimiya; Arakawa, Yoshihiro [Department of Aeronautics and Astronautics, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)

    2005-04-27

    CW laser propulsion has been investigated to develop a prospective propulsion system that may be used in space. OTV (Orbit Transfer Vehicle) is placed as one of the most effective applications of the propulsion system. In this study, the energy partitioning of incident laser energy was investigated over the wide range of velocity of the flow field in low pressure. Flow velocity is thought to have significant effects on energy conversion process because the distribution of temperature and the position of a laser sustained plasma in the focusing laser beam should be determined so that flow velocity and propagation velocity of optical discharge balance out. It was found that the higher energy conversion efficiency can be achieved by lowering the pressure and increasing the velocity of the flow field.

  4. Potential impact of ZT = 4 thermoelectric materials on solar thermal energy conversion technologies.

    PubMed

    Xie, Ming; Gruen, Dieter M

    2010-11-18

    State-of-the-art methodologies for the conversion of solar thermal power to electricity are based on conventional electromagnetic induction techniques. If appropriate ZT = 4 thermoelectric materials were available, it is likely that conversion efficiencies of 30-40% could be achieved. The availability of all solid state electricity generation would be a long awaited development in part because of the elimination of moving parts. This paper presents a preliminary examination of the potential performance of ZT = 4 power generators in comparison with Stirling engines taking into account specific mass, volume and cost as well as system reliability. High-performance thermoelectrics appear to have distinct advantages over magnetic induction technologies. PMID:20196558

  5. Thermal Properties of Refractory Metals for Advanced Energy Conversion Systems

    NASA Astrophysics Data System (ADS)

    Ozaki, Yo.

    1994-01-01

    The selection of materials for advanced nuclear energy converters is a crucial issue since many of their components must be able to sustain high temperature operation for long periods of time. Prime candidate materials for the converters including W-HfC and refractory metal carbides (TaC, NbC, HfC, ZrC and WC) were investigated in this research. The objectives were to predict the lifetime of the W-HfC alloy, via a thorough investigation of the microstructure evolution, and to obtain an understanding of the high temperature thermal radiative characteristics of the alloy and the carbides, via emissivity measurements. The W-HfC alloy was found to have an extremely high recrystallization temperature. This strong resistance to recrystallization was concluded to be one of the reasons that W-HfC has superior high temperature strength. The coarsening of HfC particles was found to be the precursor for recrystallization and grain growth. The coarsening of finely dispersed HfC particles in W-HfC was investigated and diffusion of Hf in W were measured to determine the diffusion contribution to the coarsening process. The coarsening process appears to be controlled by two energy barriers. One dictated by the diffusion of hafnium and the other by the solubility limit as a function of temperature. From the environmental aspects, the high temperature compatibility of the alloy with either a CVD-W coating or rm UO_2 nuclear fuel were investigated. Neither of these was found to affect the performance of the converters. Using single- and dual -wavelength radiation thermometries the high temperature emissivities of W-HfC, CVD-W and refractory metal carbides were found to be higher than previously reported. The effects of exposure to high temperatures (with and without the presence of hydrogen) on the emissivities of the carbides were also investigated and ZrC and HfC were concluded to be the most suitable materials for the nuclear energy converter application among the carbides tested. Utilizing these experimental data the lifetime of the alloy for converter applications were predicted by two methods. The first was based on the creep behavior of the W-HfC alloy and the other was based on the recrystallization resistance caused by the HfC particles. Both results indicate that the strengthening effect of the HfC particles is significantly reduced at temperatures above 1800 K due to particle coarsening.

  6. A Comparison of the Performance Capabilities of Radioisotope Energy Conversion Systems, Betavoltaic Cells, and other Nuclear Batteries

    Microsoft Academic Search

    Eric V. Steinfelds; Mark A. Prelas; Loyalka K. Sudarshan; Robert V. Tompson

    2006-01-01

    In this paper we compare the potential performance capabilities of several types of nuclear batteries to the Radioisotope Thermocouple Generators (RTG's) currently in use. There have been theoretical evaluations of, and some experimental testing of, several types of nuclear batteries including Radioisotope Energy Conversion Systems (RECS), Direct Energy Conversion (DEC) systems, and Betavoltaic Power Cells (BPC's). It has been theoretically

  7. Spectral analysis of transition metal-doped MgO “matched emitters” for thermophotovoltaic energy conversion

    Microsoft Academic Search

    L. G. Ferguson; F. Dogan

    2002-01-01

    A new, thermally excited Co\\/Ni-doped MgO ceramic emitter for TPV energy conversion is described in this work, and termed the “matched emitter” because its emissive power spectrum is very efficiently matched with the portion of the electromagnetic spectrum that can be converted directly into electrical energy by infrared responding GaSb photovoltaic cells. Ligand Field Theory calculations are used to estimate

  8. Heat to light energy conversion by emitters doped with rare-earth metal ions

    SciTech Connect

    Golovlev, V.V.; Winston Chen, C.H.; Garrett, W.R. [Health Science Research Division, Chemical and Biological Physics Section, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6378 (United States)] [Health Science Research Division, Chemical and Biological Physics Section, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6378 (United States)

    1996-07-01

    A thermodynamical consideration of a selective wavelength emitter for thermophotovoltaic energy generation is presented to express emitter emission properties through spectroscopic parameters of dopant atoms. It is found the heat-light conversion can produce nonequilibrium conditions in the emitter material due to radiative cooling of the atomic excited states. A possible influence of inter- and intra-atomic energy transitions to emitter parameters is discussed. {copyright} {ital 1996 American Institute of Physics.}

  9. A Novel Voltage Stabilization Control Scheme for Stand-alone Wind Energy Conversion Systems

    Microsoft Academic Search

    A. M. Sharaf; A. Aljankawey; I. H. Altas

    2007-01-01

    This paper proposes a novel low cost FACTS based voltage stabilization scheme for a stand-alone wind energy conversion systems using self excited squirrel-cage induction generator (SEIG) driven by a wind turbine and interfaced to electric load. The new control scheme is designed not only to ensure bus voltage stabilization, but also to improve energy utilization using a low-cost PWM-switched modulated

  10. Improved Magnetic Fusion Energy Economics Via Massive Resistive Electromagnets

    E-print Network

    for magnetic fusion reactors and instead using resistive magnet designs based on cheap copper or aluminum expensive. Today's conceptual designs of future commercial MFE (magnetic fusion energy) power plants provideImproved Magnetic Fusion Energy Economics Via Massive Resistive Electromagnets Robert D. Woolley

  11. Optimisation and comparison of integrated models of direct-drive linear machines for wave energy conversion 

    E-print Network

    Crozier, Richard Carson

    2014-06-30

    Combined electrical and structural models of five types of permanent magnet linear electrical machines suitable for direct-drive power take-off on wave energy applications are presented. Electromagnetic models were ...

  12. The Photoelectrochemistry of Semiconductors: Solar Energy Conversion and Selective Photoetching.

    NASA Astrophysics Data System (ADS)

    Harris, Derek Brent

    Two different aspects of semiconductor photoelectrochemistry were investigated. The use of a photoelectrochemical, PEC, cell to convert solar energy into electrical energy was studied using the CdSe/Polysulfide liquid junction solar cell. The PEC selective etching of III-V semiconductors was also demonstrated. When the cation was changed in the CdSe/Polysulfide cell there was an improvement in both the current response and the open-circuit photovoltage. Increases in efficiency as high as 30% were found when the cation was changed from K to Cs. The cation, however, is not directly involved in the charge transfer reactions at the photoanode. The mechanism for the improvement with cation was investigated by performance and impedance measurements. It was found that the changes in the performance of the solar cell are related to both a change in the distribution ofthe polysulfide species and change in the semiconductor surface with the addition of Cs. PEC etching of p-InP, n-InAs, and p-InAs was also investigated. Photogenerated electrons in p-InP do not lead to the direct dissolution of the surface in photoetching. A two step etching process was used. At cathodic overpotentials the photogenerated electrons reduced the surface to In; the cell was then switched to cathodic overpotentials and the hole concentration at the surface increased and the In was preferentially oxidized and dissolved into solution. The etch process was optimized for electrolyte, andodic and cathodic overpotentials, temperature, and cycle time. Etch rates as high as 1 micron per minute were measured with high selectivity between illuminated and unilluminated areas. p-InAs with a much smaller band gap would not etch selectively. The oxidation of the n-InAs at cathodic overpotentials led to the direct dissolution of the crystal and the two step process was not needed. The process was optimized with respect to temperature, electrolyte, and potential. The best selectivity between light and dark etch rates was 4 to 1 and the etch rate was 0.03 microns per minute.

  13. Linear PM Generator system for wave energy conversion in the AWS

    Microsoft Academic Search

    Henk Polinder; Michiel E. C. Damen; Fred Gardner

    2004-01-01

    The Archimedes Wave Swing is a system that converts ocean wave energy into electric energy. A pilot plant of this system has been built. The generator system consists of a permanent-magnet linear synchronous generator with a current source inverter (CSI). The correlation between the measured and the calculated parameters of the designed generator is reasonable. The annual energy yield of

  14. Review of electrochemical energy conversion and storage for ocean thermal and wind energy systems

    NASA Astrophysics Data System (ADS)

    Landgrebe, A. R.; Donley, S. W.

    A literature review on electrochemical storage techniques related to ocean thermal (OTEC) and wind energy conversion systems (WECS) is presented. Battery use for WECS is foreseen because of siting size, variable capacity, quiet operation, and high efficiency; high cost and the necessity for further input voltage regulation is noted, as are prospects for technology transfer from existing programs for photovoltaic panel battery development. Fuel cells, which can run on hydrogen, ammonia, methanol, naphtha, etc., are encouraging because capacity increases are possible by simple addition of more fuel, and high thermal efficiency. Electrolytic use is seen as a cheap replacement source of electricity for metals refining and brine electrolysis. Systems of energy 'bridges' for OTEC plants, to transmit power to users, are reviewed as redox-flow, lithium-water-air, and aluminum batteries, fuel cells, electrolytic hydrogen, methane, and ammonia production, and the use of OTECs as power sources for floating factories. Directions of future research are indicated, noting that WECS will be in commercial production by 1985, while OTEC is far term, around 2025.

  15. SOLID STATE ENERGY CONVERSION ALLIANCE DELPHI SOLID OXIDE FUEL CELL

    SciTech Connect

    Steven Shaffer; Sean Kelly; Subhasish Mukerjee; David Schumann; Gail Geiger; Kevin Keegan; John Noetzel; Larry Chick

    2003-12-08

    The objective of Phase I under this project is to develop a 5 kW Solid Oxide Fuel Cell power system for a range of fuels and applications. During Phase I, the following will be accomplished: Develop and demonstrate technology transfer efforts on a 5 kW stationary distributed power generation system that incorporates steam reforming of natural gas with the option of piped-in water (Demonstration System A). Initiate development of a 5 kW system for later mass-market automotive auxiliary power unit application, which will incorporate Catalytic Partial Oxidation (CPO) reforming of gasoline, with anode exhaust gas injected into an ultra-lean burn internal combustion engine. This technical progress report covers work performed by Delphi from January 1, 2003 to June 30, 2003, under Department of Energy Cooperative Agreement DE-FC-02NT41246. This report highlights technical results of the work performed under the following tasks: Task 1 System Design and Integration; Task 2 Solid Oxide Fuel Cell Stack Developments; Task 3 Reformer Developments; Task 4 Development of Balance of Plant (BOP) Components; Task 5 Manufacturing Development (Privately Funded); Task 6 System Fabrication; Task 7 System Testing; Task 8 Program Management; and Task 9 Stack Testing with Coal-Based Reformate.

  16. Energy Conversion and Utilization Technologies Program (ECUT) electrocatalysis research

    NASA Technical Reports Server (NTRS)

    Warren, L. F.

    1984-01-01

    The general field of electrocatalysis, from both the technical and business standpoints is accessed and research areas and approaches most likely to lead to substantial energy/cost savings are identified. The overall approach was to compile and evaluate available information, relying heavily on inputs/recommendations of research managers and technical personnel in responsible positions in industry and at universities. Some promising approaches identified to date include the use of transition metal compounds as electrocatalysts and the use of the new electrochemical photocapacitance spectroscopy (EPS) technique for electrocatalyst characterization/development. For the first time, an oxygen electrocatalyst based on the K2NiF4 structure was synthesized, investigated and compared with a perovskite analog. Results show that this class of materials, based on Ni(3+), forms very efficient and stable O2 anodes in basic solution and suggest that other structure-types be examined in this regard. The very difficult problem of dinitrogen and carbon dioxide electroreductions is addressed through the use of biological model systems which can mimic the enzyme processes in nature.

  17. A Rapid Method for Direct Detection of Metabolic Conversion and Magnetization Exchange with Application to Hyperpolarized Substrates

    PubMed Central

    Larson, Peder E. Z.; Kerr, Adam B.; Leon Swisher, Christine; Pauly, John M.; Vigneron, Daniel B.

    2012-01-01

    In this work, we present a new MR spectroscopy approach for directly observing nuclear spins that undergo exchange, metabolic conversion, or, generally, any frequency shift during a mixing time. Unlike conventional approaches to observe these processes, such as exchange spectroscopy (EXSY), this rapid approach requires only a single encoding step and thus is readily applicable to hyperpolarized MR in which the magnetization is not replenished after T1 decay and RF excitations. This method is based on stimulated-echoes and uses phase-sensitive detection in conjunction with precisely chosen echo times in order to separate spins generated during the mixing time from those present prior to mixing. We are calling the method Metabolic Activity Decomposition Stimulated-echo Acquisition Mode or MAD-STEAM. We have validated this approach as well as applied it in vivo to normal mice and a transgenic prostate cancer mouse model for observing pyruvate-lactate conversion, which has been shown to be elevated in numerous tumor types. In this application, it provides an improved measure of cellular metabolism by separating [1-13C]-lactate produced in tissue by metabolic conversion from [1-13C]-lactate that has flowed into the tissue or is in the blood. Generally, MAD-STEAM can be applied to any system in which spins undergo a frequency shift. PMID:23143011

  18. Conversion of surface energy and manipulation of a single droplet across micropatterned surfaces.

    PubMed

    Yang, Jing-Tang; Yang, Zong-Han; Chen, Chien-Yang; Yao, Da-Jeng

    2008-09-01

    To clarify a driving mechanism for the self-movement of a droplet across hydrophobic textured surfaces in series and to develop applications for a microfluidic device, we report a theoretical model, a microfabrication technique, and experimental measurements. The contact angle of a droplet on a composite surface, the stable surface energy level, and the energy barrier caused by hysteresis were investigated. With increasing patterned density of the microstructure, the contact angle and stable surface energy decreased gradually, but the energy barrier increased. Both the analytical results and the experimental measurements show that the surface energy for a suspended status is greater than that for a collapsed status, which produces increased energy to generate the movement of a droplet. An analysis of interactions between actuation force, resistive force, and viscous force during the motion of a droplet is based on the equilibrium between forces. From the perspective of energy conversion, the difference in surface energy between a higher state and a lower state would drive a single droplet and make it move spontaneously if it could overcome the static friction force resulting from hysteresis and the kinetic friction force under droplet movement. The mean velocity in the present device, measured to be 62.5 mm s (-1), agrees satisfactorily with the theoretical prediction. The model developed for the energy levels enables us to assess the contact mode of a droplet placed on the patterned surface. For a prediction of the transport capability of the designed devices, a theoretical interpretation of the conversion between the surface energy and the kinetic energy of the droplet establishes a criterion that the pattern density of a textured surface should be less than 0.76. The effective rate of energy conversion is estimated to be 20.6%. PMID:18683962

  19. SOLID STATE ENERGY CONVERSION ALLIANCE DELPHI SOLID OXIDE FUEL CELL

    SciTech Connect

    Steven Shaffer; Sean Kelly; Subhasish Mukerjee; David Schumann; Gail Geiger; Kevin Keegan; Larry Chick

    2004-05-07

    The objective of this project is to develop a 5 kW Solid Oxide Fuel Cell power system for a range of fuels and applications. During Phase I, the following will be accomplished: Develop and demonstrate technology transfer efforts on a 5 kW stationary distributed power generation system that incorporates steam reforming of natural gas with the option of piped-in water (Demonstration System A). Initiate development of a 5 kW system for later mass-market automotive auxiliary power unit application, which will incorporate Catalytic Partial Oxidation (CPO) reforming of gasoline, with anode exhaust gas injected into an ultra-lean burn internal combustion engine. This technical progress report covers work performed by Delphi from July 1, 2003 to December 31, 2003, under Department of Energy Cooperative Agreement DE-FC-02NT41246. This report highlights technical results of the work performed under the following tasks: Task 1 System Design and Integration; Task 2 Solid Oxide Fuel Cell Stack Developments; Task 3 Reformer Developments; Task 4 Development of Balance of Plant (BOP) Components; Task 5 Manufacturing Development (Privately Funded); Task 6 System Fabrication; Task 7 System Testing; Task 8 Program Management; Task 9 Stack Testing with Coal-Based Reformate; and Task 10 Technology Transfer from SECA CORE Technology Program. In this reporting period, unless otherwise noted Task 6--System Fabrication and Task 7--System Testing will be reported within Task 1 System Design and Integration. Task 8--Program Management, Task 9--Stack Testing with Coal Based Reformate, and Task 10--Technology Transfer from SECA CORE Technology Program will be reported on in the Executive Summary section of this report.

  20. Review of solar thermoelectric energy conversion and analysis of a two cover flat-plate solar collector

    E-print Network

    Hasan, Atiya

    2007-01-01

    The process of solar thermoelectric energy conversion was explored through a review of thermoelectric energy generation and solar collectors. Existing forms of flat plate collectors and solar concentrators were surveyed. ...

  1. A new strategy for efficient solar energy conversion: Parallel-processing with surface plasmons

    NASA Technical Reports Server (NTRS)

    Anderson, L. M.

    1982-01-01

    This paper introduces an advanced concept for direct conversion of sunlight to electricity, which aims at high efficiency by tailoring the conversion process to separate energy bands within the broad solar spectrum. The objective is to obtain a high level of spectrum-splitting without sequential losses or unique materials for each frequency band. In this concept, sunlight excites a spectrum of surface plasma waves which are processed in parallel on the same metal film. The surface plasmons transport energy to an array of metal-barrier-semiconductor diodes, where energy is extracted by inelastic tunneling. Diodes are tuned to different frequency bands by selecting the operating voltage and geometry, but all diodes share the same materials.

  2. New device architecture of a thermoelectric energy conversion for recovering low-quality heat

    NASA Astrophysics Data System (ADS)

    Kim, Hoon; Park, Sung-Geun; Jung, Buyoung; Hwang, Junphil; Kim, Woochul

    2014-03-01

    Low-quality heat is generally discarded for economic reasons; a low-cost energy conversion device considering price per watt, /W, is required to recover this waste heat. Thin-film based thermoelectric devices could be a superior alternative for this purpose, based on their low material consumption; however, power generated in conventional thermoelectric device architecture is negligible due to the small temperature drop across the thin film. To overcome this challenge, we propose new device architecture, and demonstrate approximately 60 Kelvin temperature differences using a thick polymer nanocomposite. The temperature differences were achieved by separating the thermal path from the electrical path; whereas in conventional device architecture, both electrical charges and thermal energy share same path. We also applied this device to harvest body heat and confirmed its usability as an energy conversion device for recovering low-quality heat.

  3. Electrokinetic Energy Conversion in Nanofluidic Channels: Addressing the Loose Ends in Nanodevice Efficiency

    E-print Network

    Bakli, Chirodeep

    2014-01-01

    We bring out a non-trivial coupling of the intrinsic wettability, surface charge and electrokinetic energy conversion characteristics of nanofluidic devices. Our analyses demonstrate that nanofluidic energy conversion efficiencies may get amplified with increase in surface charge density, not perpetually, but only over a narrow regime of low surface charges, and may get significantly arrested to reach a plateau beyond a threshold surface charging condition, as attributed to a complex interplay between fluid structuration and ionic transport within a charged interfacial layer. We explain the corresponding findings from our molecular dynamics simulations with the aid of a simple modified continuum based theory. We attribute our findings to hitherto-unexplored four-way integration of surface charge, interfacial slip, ionic transport, and the water molecule structuration. The consequent complex non-linear nature of the energy transfer characteristics may bear far-ranging scientific and technological implications ...

  4. Carbon nitride in energy conversion and storage: recent advances and future prospects.

    PubMed

    Gong, Yutong; Li, Mingming; Wang, Yong

    2015-03-01

    With the explosive growth of energy consumption, the exploration of highly efficient energy conversion and storage devices becomes increasingly important. Fuel cells, supercapacitors, and lithium-ion batteries are among the most promising options. The innovation of these devices mainly resides in the development of high-performance electrode materials and catalysts. Graphitic carbon nitride (g-C3 N4 ), due to structural and chemical properties such as semiconductor optical properties, rich nitrogen content, and tunable porous structure, has drawn considerable attention and shown great potential as an electrode material or catalyst in energy conversion and storage devices. This review covers recent progress in g-C3 N4 -containing systems for fuel cells, electrocatalytic water splitting devices, supercapacitors, and lithium-ion batteries. The corresponding catalytic mechanisms and future research directions in these areas are also discussed. PMID:25688746

  5. Magnetic resonance spectroscopy in the prediction of early conversion from amnestic mild cognitive impairment to dementia: a prospective cohort study

    PubMed Central

    Fayed, Nicolas; Sarasa, Manuel

    2011-01-01

    Background Mild cognitive impairment (MCI) of an amnestic type is a common condition in older people and highly predictive of Alzheimer's disease (AD). To date, there is no clear consensus regarding the best antecedent biomarker to predict early conversion to AD. Objective The aim of the study is to demonstrate that 1H magnetic resonance spectroscopy (MRS) of the brain in MCI patients may predict early conversion to dementia within the 2-year period after baseline assessment. Methods A cohort of patients fulfilling the criteria of amnestic MCI were enrolled consecutively. At baseline the patients underwent neuropsychological examination, standard blood tests and APOE genotype. 1H-MRS (1.5 T) of the brain was carried out by exploring two areas: the posteromedial bilateral parietal lobe and left medial occipital lobe. The patients were followed up to detect conversion to probable AD according to the National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association group criteria. Results After a 2-year follow-up, 27 (38%) patients converted to AD. The mean N-acetyl-aspartate/creatine (NAA/Cr) ratio in the posteromedial bilateral parietal cortex was 1.38 in converters versus 1.49 in non-converters (p<0.0001). An NAA/Cr ratio equal to or lower than 1.43 in this area predicted conversion to probable AD at 74.1% sensitivity and 83.7% specificity (area under the curve: 0.84; 95% CI 0.73 to 0.92). The cross-validated accuracy of classification was 82%, which reaches 85% when the APOE4 genotype and memory test are included in the analysis. In the left medial occipital lobe, the predictive value was somewhat lower with 85.2% sensitivity and 61.4% specificity (area under the curve: 0.8; 95% CI 0.69 to 0.89). Neither the APOE4 genotype nor leuco-araiosis was predictive of conversion to dementia. Conclusion MRS is a valuable biomarker to predict early conversion to dementia in patients with amnestic MCI. PMID:22021723

  6. Current Research on Thermochemical Conversion of Biomass at the National Renewable Energy Laboratory

    SciTech Connect

    Baldwin, R. M.; Magrini-Bair, K. A.; Nimlos, M. R.; Pepiot, P.; Donohoe, B. S.; Hensley, J. E.; Phillips, S. D.

    2012-04-05

    The thermochemical research platform at the National Bioenergy Center, National Renewable Energy Laboratory (NREL) is primarily focused on conversion of biomass to transportation fuels using non-biological techniques. Research is conducted in three general areas relating to fuels synthesis via thermochemical conversion by gasification: (1) Biomass gasification fundamentals, chemistry and mechanisms of tar formation; (2) Catalytic tar reforming and syngas cleaning; and (3) Syngas conversion to mixed alcohols. In addition, the platform supports activities in both technoeconomic analysis (TEA) and life cycle assessment (LCA) of thermochemical conversion processes. Results from the TEA and LCA are used to inform and guide laboratory research for alternative biomass-to-fuels strategies. Detailed process models are developed using the best available material and energy balance information and unit operations models created at NREL and elsewhere. These models are used to identify cost drivers which then form the basis for research programs aimed at reducing costs and improving process efficiency while maintaining sustainability and an overall net reduction in greenhouse gases.

  7. Magnetic Energy Storage System: Superconducting Magnet Energy Storage System with Direct Power Electronics Interface

    SciTech Connect

    None

    2010-10-01

    GRIDS Project: ABB is developing an advanced energy storage system using superconducting magnets that could store significantly more energy than today’s best magnetic storage technologies at a fraction of the cost. This system could provide enough storage capacity to encourage more widespread use of renewable power like wind and solar. Superconducting magnetic energy storage systems have been in development for almost 3 decades; however, past devices were designed to supply power only for short durations—generally less than a few minutes. ABB’s system would deliver the stored energy at very low cost, making it ideal for eventual use in the electricity grid as a costeffective competitor to batteries and other energy storage technologies. The device could potentially cost even less, on a per kilowatt basis, than traditional lead-acid batteries.

  8. Energy Conversion Efficiency in Exciton Process for Single and Bulk Heterojunction Organic Solar Cells

    NASA Astrophysics Data System (ADS)

    Isoda, Satoru

    2008-12-01

    The energy conversion efficiency in an exciton process, defined as the total energy density of excitons used for charge separation at the donor/acceptor heterojunction per incident optical power density, for organic solar cells, has been modeled on the basis of the rate processes for the charge separation of excitons into free charges at the heterojunction, the quenching of excitons at the organic layer/metal electrode interface, and the exciton diffusion in the bulk layer. As an application of this modeling, the energy conversion efficiency in the exciton process was analyzed for the CuPc/C60 heterojunction under various conditions. In this way, the upper limit of the energy conversion efficiency in the exciton process, under 1 sun (0.1 W/cm2) AM1.5 solar illumination, was estimated to be 7.4% for the optimized single heterojunction structure and approximately 40% for the optimized bulk heterojunction structure in which the donor and acceptor components are vertically aligned in the form of alternating donor/acceptor lamellae.

  9. The Status of Thermophotovoltaic Energy Conversion Technology at Lockheed Martin Corp.

    SciTech Connect

    E.J. Brown; P.F. Baldasaro; S.R. Burger; L.R. Danielson; D.M. DePoy; G.J. Nichols; W.F. Topper; T.D. Rahmlow

    2003-01-31

    In a thermophotovoltaic (TPV) energy conversion system, a heated surface radiates in the mid-infrared range onto photodiodes which are sensitive at these energies. Part of the absorbed energy is converted into electric output. Conversion efficiency is maximized by reducing the absorption of non-convertible energy with some form of spectral control. In a TPV system, many technology options exist. The development efforts have concentrated on flat-plate geometries with greybody radiators, low bandgap quaternary diodes, front surface tandem filters and a multi-chip module (MCM) approach that allows selective fabrication processes to match diode performance. Recently, the authors achieved conversion efficiencies of about 20% (radiator 950 C, diodes 22 C) for a module in a prototypic cavity test environment. These tests employed InGaAsSb diodes with 0.52 eV bandgap and front surface filters for spectral control. This paper provides details of the individual system components and describes the measurement technique used to record these efficiencies.

  10. System for thermal energy storage, space heating and cooling and power conversion

    DOEpatents

    Gruen, Dieter M. (Downers Grove, IL); Fields, Paul R. (Chicago, IL)

    1981-04-21

    An integrated system for storing thermal energy, for space heating and cong and for power conversion is described which utilizes the reversible thermal decomposition characteristics of two hydrides having different decomposition pressures at the same temperature for energy storage and space conditioning and the expansion of high-pressure hydrogen for power conversion. The system consists of a plurality of reaction vessels, at least one containing each of the different hydrides, three loops of circulating heat transfer fluid which can be selectively coupled to the vessels for supplying the heat of decomposition from any appropriate source of thermal energy from the outside ambient environment or from the spaces to be cooled and for removing the heat of reaction to the outside ambient environment or to the spaces to be heated, and a hydrogen loop for directing the flow of hydrogen gas between the vessels. When used for power conversion, at least two vessels contain the same hydride and the hydrogen loop contains an expansion engine. The system is particularly suitable for the utilization of thermal energy supplied by solar collectors and concentrators, but may be used with any source of heat, including a source of low-grade heat.

  11. High efficiency ? radioisotope energy conversion using reciprocating electromechanical converters with integrated betavoltaics

    NASA Astrophysics Data System (ADS)

    Duggirala, Rajesh; Li, Hui; Lal, Amit

    2008-04-01

    We demonstrate a 5.1% energy conversion efficiency Ni63 radioisotope power generator by integrating silicon betavoltaic converters with radioisotope actuated reciprocating piezoelectric unimorph cantilever converters. The electromechanical energy converter efficiently utilizes both the kinetic energy and the electrical charge of the 0.94?W ? radiation from a 9mCi Ni63 thin film source to generate maximum (1) continuous betavoltaic electrical power output of 22nW and (2) pulsed piezoelectric electrical power output of 750?W at 0.07% duty cycle. The electromechanical converters can be potentially used to realize 100year lifetime power sources for powering periodic sampling remote wireless sensor microsystems.

  12. Solid state ionics and optical materials technology for energy efficiency, solar energy conversion, and environment control

    NASA Astrophysics Data System (ADS)

    Lusis, Andrejs R.

    1991-12-01

    The fundamental electronic properties (including optical) of a solid are determined by the character of the interaction between its ionic and electronic subsystems. The state of the ionic subsystem can be changed persistently and reversibly by an external stimulus (current, light). The pertinent ion-controlled phenomena in the solids (solid electrolytes or mixed conductors) causes the ions to be inserted, extracted, transferred, or absorbed or transforms the states of the ions by redox reactions in the bulk or on the surface of the solid or on the interface of a (laminar or planar) solid ionic heterosystem. Several functions can be accomplished: (1) the optical response function of the solid or heterosystem can be controlled (variable optics) by ionic processes (redox reactions); (2) the external stimulus (current, light) or absorbed surface molecules, atoms or ions from a gas or liquid-like environment can be detected by a corresponding optical response (physical or chemical sensing); (3) the ion insertion, extraction, transfer, and storage in a solid ionic heterosystem implies energy conversion and accumulation. Redox reactions create color centers and are related to chromogenics (chemi-, thermo-, photo-, cathodo-, and electro- chromic phenomena). Solid ionic systems are sensitive to the chemical composition of the environment. Solid ionic heterosystems (electrode- electrolyte) form a three-phase interface together with the environment. A laminar heterosystem can be used for `smart windows,' large scale memory displays with small energy consumption, reversible electrochromic photography, and rechargeable solar batteries. A combination of laminar and planar heterosystems can be used for integrated optics and for special opto-electrochemical `smart sensors.' Solid state ionics constitutes the scientific and technological base for the creation and design of devices for the above mentioned applications.

  13. Performance and economics of advanced energy conversion systems for coal and coal-derived fuels

    NASA Technical Reports Server (NTRS)

    Corman, J. C.; Fox, G. R.

    1978-01-01

    The desire to establish an efficient Energy Conversion System to utilize the fossil fuel of the future - coal - has produced many candidate systems. A comparative technical/economic evaluation was performed on the seven most attractive advanced energy conversion systems. The evaluation maintains a cycle-to-cycle consistency in both performance and economic projections. The technical information base can be employed to make program decisions regarding the most attractive concept. A reference steam power plant was analyzed to the same detail and, under the same ground rules, was used as a comparison base. The power plants were all designed to utilize coal or coal-derived fuels and were targeted to meet an environmental standard. The systems evaluated were two advanced steam systems, a potassium topping cycle, a closed cycle helium system, two open cycle gas turbine combined cycles, and an open cycle MHD system.

  14. Optimize out-of-core thermionic energy conversion for nuclear electric propulsion

    NASA Technical Reports Server (NTRS)

    Morris, J. F.

    1978-01-01

    Thermionic energy conversion (TEC) potentialities for nuclear electric propulsion (NEP) are examined. Considering current designs, their limitations, and risks raises critical questions about the use of TEC for NEP. Apparently a reactor cooled by hotter-than-1675 K heat pipes has good potentialities. TEC with higher temperatures and greater power densities than the currently proposed 1650 K, 5-to-6 W/sq cm version offers substantial gains. Other approaches to high-temperature electric isolation appear also promising. A high-power-density, high-temperature TEC for NEP appears, therefore, attainable. It is recommended to optimize out-of-core thermionic energy conversion for nuclear electric propulsion. Although current TEC designs for NEP seem unnecessary compared with Brayton versions, large gains are apparently possible with increased temperatures and greater power densities.

  15. Conventional and TFPM linear generators for direct-drive wave energy conversion

    Microsoft Academic Search

    Henk Polinder; Barrie C. Mecrow; Alan G. Jack; Phillip G. Dickinson; Markus A. Mueller

    2005-01-01

    The archimedes wave swing (AWS) is a system that converts ocean wave energy into electric energy. The goal of the research described in this paper is to identify the most suitable generator type for this application. Of the conventional generator types, the three-phase permanent-magnet synchronous generator with iron in both stator and translator is most suitable, because it is cheaper

  16. Nanotube liquid crystal elastomers: photomechanical response and flexible energy conversion of layered polymer composites.

    PubMed

    Fan, Xiaoming; King, Benjamin C; Loomis, James; Campo, Eva M; Hegseth, John; Cohn, Robert W; Terentjev, Eugene; Panchapakesan, Balaji

    2014-09-01

    Elastomeric composites based on nanotube liquid crystals (LCs) that preserve the internal orientation of nanotubes could lead to anisotropic physical properties and flexible energy conversion. Using a simple vacuum filtration technique of fabricating nanotube LC films and utilizing a transfer process to poly (dimethyl) siloxane wherein the LC arrangement is preserved, here we demonstrate unique and reversible photomechanical response of this layered composite to excitation by near infra-red (NIR) light at ultra-low nanotube mass fractions. On excitation by NIR photons, with application of small or large pre-strains, significant expansion or contraction of the sample occurs, respectively, that is continuously reversible and three orders of magnitude larger than in pristine polymer. Schlieren textures were noted in these LC composites confirming long range macroscopic nematic order of nanotubes within the composites. Order parameters of LC films ranged from S(optical) = 0.51-0.58 from dichroic measurements. Film concentrations, elastic modulus and photomechanical stress were all seen to be related to the nematic order parameter. For the same nanotube concentration, the photomechanical stress was almost three times larger for the self-assembled LC nanotube actuator compared to actuator based on randomly oriented carbon nanotubes. Investigation into the kinetics of photomechanical actuation showed variation in stretching exponent ? with pre-strains, concentration and orientation of nanotubes. Maximum photomechanical stress of ? 0.5 MPa W(-1) and energy conversion of ? 0.0045% was achieved for these layered composites. The combination of properties, namely, optical anisotropy, reversible mechanical response to NIR excitation and flexible energy conversion all in one system accompanied with low cost makes nanotube LC elastomers important for soft photochromic actuation, energy conversion and photo-origami applications. PMID:25116197

  17. Velocity and energy conversion efficiency characteristics of ionic wind generator in a multistage configuration

    Microsoft Academic Search

    C. Kim; K. C. Noh; J. Hwang

    2010-01-01

    This paper reports the experimental and theoretical analysis of the ionic wind velocity and electrical-to-kinetic energy conversion efficiency in an ionic wind generator with six stages in series. Each stage contained a pair of cylindrical multipin-to-ring electrodes. The experiments were carried out in a negative dc corona discharge and the experimental results showed that both the velocity and efficiency are

  18. Characterization of energy conversion based on metabolic flux analysis in mixotrophic liverwort cells, Marchantia polymorpha

    Microsoft Academic Search

    Jun-ichi Hata; Qiang Hua; Chen Yang; Kazuyuki Shimizu; Masahito Taya

    2000-01-01

    In order to characterize the contributions of respiratory and photosynthetic actions to energy conversions, the mixotrophic cells of Marchantia polymorpha were cultivated in the medium containing 10kg\\/m3 glucose as an organic carbon source. The cultures were conducted with the supply of ordinary air (0.03% CO2) at constant incident light intensities of 50 and 180W\\/m2. From the results of metabolic analysis,

  19. Progress in the technology of energy conversion from woody biomass in Indonesia

    Microsoft Academic Search

    Tjutju Nurhayati; Yani Waridi; Han Roliadi

    2006-01-01

    Sustainable and renewable natural resources as biomass that contains carbon and hydrogen elements can be a potential raw materials\\u000a for energy conversion. In Indonesia, they comprise variable-sized wood from forests (i.e. natural forests, plantations and\\u000a community forests that commonly produce small-diameter logs used as firewood by local people), woody residues from logging\\u000a and wood industries, oil-palm shell waste from crude

  20. The Status of Thermophotovoltaic Energy Conversion Technology at Lockheed Martin Corporation

    SciTech Connect

    EJ Brown; PF Baldasaro; SR Burger; LR Danielson; DM DePoy; JM Dolatowski; PM Fourspring; GJ Nichols; WF Topper; TD Rahmlow

    2004-07-29

    In a thermophotovoltaic (TPV) energy conversion system, a heated surface radiates in the mid-infrared range onto photocells which are sensitive at these energies. Part of the absorbed energy is converted into electric output. Conversion efficiency is maximized by reducing the absorption of non-convertible energy with some form of spectral control. In a TPV system, many technology options exist. Our development efforts have concentrated on flat-plate geometries with greybody radiators, front surface tandem filters and a multi-chip module (MCM) approach that allows selective fabrication processes to match cell performance. Recently, we discontinued development of GaInAsSb quaternary cell semiconductor material in favor of ternary GaInAs material. In our last publication (Ref. 1), the authors reported conversion efficiencies of about 20% (radiator 950 C, cells 22 C) for small modules (1-4 cm{sup 2}) tested in a prototypic cavity test environment. Recently, we have achieved measured conversion efficiencies of about 12.5% in larger ({approx}100 cm{sup 2}) test arrays. The efficiency reduction in the larger arrays was probably due to quality and variation of the cells as well as non-uniform illumination from the hot radiator to the cold plate. Modules in these tests used GaInAsSb cells with 0.52 eV bandgap and front surface filters for spectral control. This paper provides details of the individual system components and the rationale for our technical decisions. It also describes the measurement techniques used to record these efficiencies.

  1. Recommended methods for evaluating the benefits of ECUT Program outputs. [Energy Conversion and Utilization

    SciTech Connect

    Levine, L.O.; Winter, C.

    1986-03-01

    This study was conducted to define and develop techniques that could be used to assess the complete spectrum of positive effects resulting from the Energy Conversion and Utilization Technologies (ECUT) Program activities. These techniques could then be applied to measure the benefits from past ECUT outputs. In addition, the impact of future ECUT outputs could be assessed as part of an ongoing monitoring process, after sufficient time has elapsed to allow their impacts to develop.

  2. ENERGY CONVERSION IN A HYDROGEN FUELED DIESEL ENGINE: OPTIMIZATION OF THE MIXTURE FORMATION AND COMBUSTION

    Microsoft Academic Search

    PETER PRECHTL; FRANK DORER; FRANZ MAYINGER

    A large-bore, four-stroke engine, with high pressure injection and compression ignition, running with hydrogen, is a modern concept for clean energy conversion without CO2 emission. The key processes for reliable engine operation are a good mixture formation, a reliable ignition and efficient combustion. The investigations of these processes are carried out in a rapid compression machine, with modern optical measurement

  3. Conversion of heating system for integral quench carburizing furnace saves energy

    Microsoft Academic Search

    Swintek

    1989-01-01

    An integral quench carburizing furnace converted to a natural-gas-fired, single-ended radiant-tube recuperative-type burner is economical to operate and maintain. Use of single-ended radiant tube (SER) burner technology is one of the keys to the energy savings; conversion to natural gas operation is the other. A small, inside tube housing a nozzle-mix burner provides the heat transfer surface area for preheating

  4. Nanotube liquid crystal elastomers: photomechanical response and flexible energy conversion of layered polymer composites

    NASA Astrophysics Data System (ADS)

    Fan, Xiaoming; King, Benjamin C.; Loomis, James; Campo, Eva M.; Hegseth, John; Cohn, Robert W.; Terentjev, Eugene; Panchapakesan, Balaji

    2014-09-01

    Elastomeric composites based on nanotube liquid crystals (LCs) that preserve the internal orientation of nanotubes could lead to anisotropic physical properties and flexible energy conversion. Using a simple vacuum filtration technique of fabricating nanotube LC films and utilizing a transfer process to poly (dimethyl) siloxane wherein the LC arrangement is preserved, here we demonstrate unique and reversible photomechanical response of this layered composite to excitation by near infra-red (NIR) light at ultra-low nanotube mass fractions. On excitation by NIR photons, with application of small or large pre-strains, significant expansion or contraction of the sample occurs, respectively, that is continuously reversible and three orders of magnitude larger than in pristine polymer. Schlieren textures were noted in these LC composites confirming long range macroscopic nematic order of nanotubes within the composites. Order parameters of LC films ranged from Soptical = 0.51-0.58 from dichroic measurements. Film concentrations, elastic modulus and photomechanical stress were all seen to be related to the nematic order parameter. For the same nanotube concentration, the photomechanical stress was almost three times larger for the self-assembled LC nanotube actuator compared to actuator based on randomly oriented carbon nanotubes. Investigation into the kinetics of photomechanical actuation showed variation in stretching exponent ? with pre-strains, concentration and orientation of nanotubes. Maximum photomechanical stress of ˜0.5 MPa W-1 and energy conversion of ˜0.0045% was achieved for these layered composites. The combination of properties, namely, optical anisotropy, reversible mechanical response to NIR excitation and flexible energy conversion all in one system accompanied with low cost makes nanotube LC elastomers important for soft photochromic actuation, energy conversion and photo-origami applications.

  5. FPGA-Based Real-Time Power Converter Failure Diagnosis for Wind Energy Conversion Systems

    Microsoft Academic Search

    Shahram Karimi; Arnaud Gaillard; Philippe Poure; Shahrokh Saadate

    2008-01-01

    This paper discusses the design, implementation, experimental validation, and performances of a field-programmable gate array (FPGA)-based real-time power converter failure diagnosis for three-leg fault tolerant converter topologies used in wind energy conversion systems (WECSs). The developed approach minimizes the time interval between the fault occurrence and its diagnosis. We demonstrated the possibility to detect a faulty switch in less than

  6. Commercial applications of thermionic conversion using a fusion reactor energy source - A preliminary assessment

    Microsoft Academic Search

    T. G. Frank; L. A. Booth

    1978-01-01

    A preliminary assessment of using thermionic conversion as a topping cycle for fusion reactors is presented. Because of mitigation of restrictive temperature limitations for fusion-reactor blankets, fusion reactors may offer significant advantages, compared to fission reactors and fossil-fuel energy sources, for utilizing thermionic topping cycles. A system with a thermionic topping cycle and a conventional steam-turbine generator that utilizes the

  7. Commercial application of thermionic conversion using a fusion reactor energy source. A preliminary assessment

    Microsoft Academic Search

    T. G. Frank; E. A. Kern; L. A. Booth

    1977-01-01

    A preliminary assessment of using thermionic conversion as a topping cycle for fusion reactors is presented. Because of the absence of restrictive temperature limitations for fusion-reactor blankets, fusion reactors may offer significant advantages, compared to fission reactors and fossil-fuel energy sources, for utilizing thermionic topping cycles. A system with a thermionic topping cycle and a conventional steam-turbine generator that utilizes

  8. Solar thermochemical energy conversion and transport. Final report 15 Mar 77-30 Sep 82

    Microsoft Academic Search

    J. H. McCrary; G. E. McCrary

    1982-01-01

    The high temperature catalytic dissociation of SOâ and the COâ-CHâ reforming-methanation cycle are important chemical processes being considered in the development and application of solar-thermal energy conversion, transport, and storage systems. Separate facilities for evaluating chemical converter-heat exchangers at temperatures to 1000 C with high flow rates of SOâ and of mixtures of COâ and CHâ feedstocks have been assembled

  9. Physicochemical upgrading of agroresidues as feedstocks for energy production via thermochemical conversion methods

    Microsoft Academic Search

    S. Arvelakis; E. G. Koukios

    2002-01-01

    Ash-related problems including deposition, slagging, fouling, sintering, and agglomeration, caused during the operation of biomass gasifiers and combustors using various agroresidues, e.g., wheat straw, olive residue, corn cobs, as feedstocks constitute the limiting factor for a broad use of this kind of biomass materials for energy production via thermochemical conversion methods.Ash content minimization and simultaneous removal of a number of

  10. Solar energy conversion systems engineering and economic analysis radiative energy input/thermal electric output computation. Volume III

    SciTech Connect

    Russo, G.

    1982-09-01

    The direct energy flux analytical model, an analysis of the results, and a brief description of a non-steady state model of a thermal solar energy conversion system implemented on a code, SIRR2, as well as the coupling of CIRR2 which computes global solar flux on a collector and SIRR2 are presented. It is shown how the CIRR2 and, mainly, the SIRR2 codes may be used for a proper design of a solar collector system. (LEW)

  11. Phase evolution in 57Fe/Al multilayers studied through dc magnetization, conversion electron Mössbauer spectroscopy, and transmission electron microscopy

    NASA Astrophysics Data System (ADS)

    Jani, Snehal; Sebastian, Varkey; Lakshmi, N.; Reddy, V. R.; Venugopalan, K.; Gupta, Ajay; Lalla, N. P.

    2008-12-01

    Fe/Al multilayer thin films with an overall atomic concentration ratio of Fe:Al=1:2 have been prepared by ion-beam sputtering. Phase formation and microstructural evolution with thermal annealing have been studied by x-ray reflectivity, cross-sectional transmission electron microscopy, dc magnetization, and conversion electron Mössbauer spectroscopy. These studies show that although the starting composition is Al rich, the intermixing of Fe and Al at the interfaces leads to the formation of a magnetic Fe3Al-like region at the interface. Thus, the magnetic contribution in the as-deposited multilayer structure (MLS) is not only from pure Fe but also from an Fe3Al-like region formed at the interface. On annealing the MLS, a stable nonmagnetic MLS consisting of intermetallic B2 Fe50Al50 separated by thin Al layers is formed. Further annealing only induces better ordering of Fe50Al50 and does not destroy the MLS.

  12. Solar-chemical energy conversion via reversible liquid phase Diels-Alder reactions. Final technical report

    SciTech Connect

    Lenz, T.G.; Hegedus, L.S.; Vaughan, J.D.

    1983-05-01

    Thermochemical energy conversion at moderate or low temperature (< about 400/sup 0/C) employing liquid phase components throughout a cycle is suggested as a promising concept for high-efficiency conversion of solar energy to a convenient chemical form. In particular, we propose liquid phase Diels-Alder cycloaddition chemistry as an important class of reversible reactions for such low or moderate temperature thermochemical energy conversion systems. One of the important attributes of thermally driven Diels-Alder reactions is their concerted mechanism, with consequent high yields and efficiencies relative to liquid photochemical systems. Since the systems we propose involve organic species, with thermal stability concerns about 400/sup 0/C, it is important to demonstrate equilibrium shift capability for the highly energetic reactions sought. We have therefore carried out experimental studies with model liquid Diels-Alder systems that clearly demonstrate the degree of control over equilibrium available through substituent entropy effects. These results are of importance as regards subsequent systematic identification of Diels-Alder reactions having ideal thermochemical and physical properties.

  13. Influence of ambient air pressure on the energy conversion of laser-breakdown induced blast waves

    NASA Astrophysics Data System (ADS)

    Wang, Bin; Komurasaki, Kimiya; Arakawa, Yoshihiro

    2013-09-01

    Influence of ambient pressure on energy conversion efficiency from a Nd?:?glass laser pulse (? = 1.053 µm) to a laser-induced blast wave was investigated at reduced pressure. Temporal incident and transmission power histories were measured using sets of energy meters and photodetectors. A half-shadowgraph half-self-emission method was applied to visualize laser absorption waves. Results show that the blast energy conversion efficiency ?bw decreased monotonically with the decrease in ambient pressure. The decrease was small, from 40% to 38%, for the pressure change from 101 kPa to 50 kPa, but the decrease was considerable, to 24%, when the pressure was reduced to 30 kPa. Compared with a TEA-CO2-laser-induced blast wave (? = 10.6 µm), higher fraction absorption in the laser supported detonation regime ?LSD of 90% was observed, which is influenced slightly by the reduction of ambient pressure. The conversion fraction ?bw/?LSD?90% was achieved at pressure >50 kPa, which is significantly higher than that in a CO2 laser case.

  14. Magnetized anisotropic ghost dark energy cosmological model

    NASA Astrophysics Data System (ADS)

    Das, Kanika; Sultana, Tazmin

    2015-06-01

    We present in this paper a LRS Bianchi type I cosmological model with dark matter and anisotropic ghost dark energy in presence of magnetic field. We have solved the Einstein's field equations with a particular form of Hubble parameter. The physical and geometrical behaviors of the model are discussed. It is observed that the anisotropy of the universe and that of the ghost dark energy tends to zero at late times and the universe becomes spatially homogeneous, isotropic and flat. The coincidence parameter increases with time. We have also studied the statefinder parameters. The results obtained are in agreement with the recent days observations.

  15. Pulsed Magnetic Fields for an XAS Energy Dispersive Beamline

    SciTech Connect

    Linden, Peter van der; Mathon, Olivier [European Synchrotron Radiation Facility, B.P.220, F-38043 Grenoble CEDEX (France); Neisius, Thomas [CRMCN-CNRS, Campus de Luminy CASE 913, F-13288 Marseille CEDEX 09 (France)

    2007-01-19

    Pulsed magnetic fields constitute an attractive alternative to superconducting magnets for many x-ray techniques. The ESRF ID24 energy dispersive beamline was used for pulsed magnetic field room temperature XMCD measurements on GdCo3. The signal has been measured up to a magnetic field of 5.5 Tesla without signs of deterioration.

  16. Renewable Energy Supply for Power Dominated, Energy Intense Production Processes - A Systematic Conversion Approach for the Anodizing Process

    NASA Astrophysics Data System (ADS)

    >D Stollenwerk, T Kuvarakul, I Kuperjans,

    2013-06-01

    European countries are highly dependent on energy imports. To lower this import dependency effectively, renewable energies will take a major role in future energy supply systems. To assist the national and inter-European efforts, extensive changes towards a renewable energy supply, especially on the company level, will be unavoidable. To conduct this conversion in the most effective way, the methodology developed in this paper can support the planning procedure. It is applied to the energy intense anodizing production process, where the electrical demand is the governing factor for the energy system layout. The differences between the classical system layout based on the current energy procurement and an approach with a detailed load-time-curve analysis, using process decomposition besides thermodynamic optimization, are discussed. The technical effects on the resulting energy systems are shown besides the resulting energy supply costs which will be determined by hourly discrete simulation.

  17. Design parameters for toroidal and bobbin magnetics. [conversion from English to metric units

    NASA Technical Reports Server (NTRS)

    Mclyman, W. T.

    1974-01-01

    The adoption by NASA of the metric system for dimensioning to replace long-used English units imposes a requirement on the U.S. transformer designer to convert from the familiar units to the less familiar metric equivalents. Material is presented to assist in that transition in the field of transformer design and fabrication. The conversion data makes it possible for the designer to obtain a fast and close approximation of significant parameters such as size, weight, and temperature rise. Nomographs are included to provide a close approximation for breadboarding purposes. For greater convenience, derivations of some of the parameters are also presented.

  18. A setup combining magneto-optical Kerr effect and conversion electron Mössbauer spectrometry for analysis of the near-surface magnetic properties of thin films.

    PubMed

    Juraszek, J; Zivotsky, O; Chiron, H; Vaudolon, C; Teillet, J

    2009-04-01

    We propose a system allowing the characterization of thin magnetic multilayer structures that combine conversion electron Mossbauer spectrometry (CEMS) under applied magnetic field with the magneto-optical Kerr effect (MOKE) technique. Measured hysteresis loops obtained from the MOKE part are used for investigation of sample surface magnetic properties. The CEMS part of such a system is suitable for studying the spatial spin distribution during magnetization reversal under applied magnetic field, whose values are established from the measured MOKE loop. The combined technique is demonstrated on the results obtained at 300 K on an exchange-coupled ferrimagnetic amorphous GdFe/TbFe bilayer, where the center of the GdFe layer is enriched in (57)Fe. Both techniques confirm in-plane uniaxial anisotropy. The spin structure at the position of the probe layer is analyzed for several values of the external magnetic field applied in the hard magnetization axis direction. PMID:19405673

  19. A setup combining magneto-optical Kerr effect and conversion electron Moessbauer spectrometry for analysis of the near-surface magnetic properties of thin films

    SciTech Connect

    Juraszek, J.; Zivotsky, O.; Chiron, H.; Vaudolon, C.; Teillet, J. [CNRS-UMR 6634, Groupe de Physique des Materiaux, Universite de Rouen, BP 12, F-76801 Saint Etienne du Rouvray (France)

    2009-04-15

    We propose a system allowing the characterization of thin magnetic multilayer structures that combine conversion electron Moessbauer spectrometry (CEMS) under applied magnetic field with the magneto-optical Kerr effect (MOKE) technique. Measured hysteresis loops obtained from the MOKE part are used for investigation of sample surface magnetic properties. The CEMS part of such a system is suitable for studying the spatial spin distribution during magnetization reversal under applied magnetic field, whose values are established from the measured MOKE loop. The combined technique is demonstrated on the results obtained at 300 K on an exchange-coupled ferrimagnetic amorphous GdFe/TbFe bilayer, where the center of the GdFe layer is enriched in {sup 57}Fe. Both techniques confirm in-plane uniaxial anisotropy. The spin structure at the position of the probe layer is analyzed for several values of the external magnetic field applied in the hard magnetization axis direction.

  20. Exchange interaction energy in magnetic recording simulation

    NASA Astrophysics Data System (ADS)

    Igarashi, Masukazu; Tonooka, Shun; Katada, Hiroyuki; Maeda, Maki; Hara, Miki; Wood, Roger

    2015-05-01

    Based on a phenomenological theory, micromagnetic simulations and experiments are used to evaluate an improved function for the exchange interaction between magnetic particles in perpendicular recording media. Assuming diluted spin layers in the particle boundary and a gradual rather than abrupt rotation of magnetization between grain cores, the exchange energy is better described by an even power series of ?, rather than a cosine function. The conventional cosine function does not have a restoring torque near ? = ? and adjacent grains tend to align strictly antiparallel. In contrast, using a power series of ?, adjacent grains tend to align at a small angle away from ? = ?. This gives rise to a small in-plane magnetization component and therefore a distinct peak in in-plane susceptibility is observed around H = 0. From magnetization measurements of a real medium, a peak is observed around H = 0, which matches with an assumption of 2 or 3 spin layers. In some situations, the exchange interaction between discretized cells for numerical calculation is better described by a power series rather than a cosine function.

  1. Study on the Feasibility of Direct Fusion Energy Conversion for Deep-Space Propulsion

    NASA Astrophysics Data System (ADS)

    Tarditi, Alfonso G.; Miley, George H.; Scott, John H.

    2012-10-01

    A significant change in the current space mission capabilities can be achieved with a highly efficient integration of a fusion energy source with an advanced space propulsion thruster, both with low specific mass. With aneutronic nuclear fusion as the high-density primary energy source, this study considers first electric energy extraction from the fusion reaction products via direct energy conversion to recirculate power as required for the operation of the fusion core. Then the beam of remaining reaction products is conditioned to achieve the optimal thrust and specific impulse for the mission. The research is specifically focused on two key issues: (i) Efficiency improvement of a Traveling Wave Direct Energy Converter (TWDEC, [1]) by achieving a higher ion beam density and optimization of the electrode coupling and of the neutralizing electron flow. (ii) A fast-particle kinetic energy-to-thrust conversion process based on collective interaction between ion bunches well separated in space [2]. Computer simulation results and a design for a basic physics experiment currently under development are reported. [4pt] [1] H. Momota et al., Fus. Tech., 35, 60(1999)[0pt] [2] A. G. Tarditi et al. Proc. NETS 2012 Conf., Woodlands, TX (2012)

  2. Resonance behavior of internal conversion coefficients at low {gamma}-ray energy

    SciTech Connect

    Trzhaskovskaya, M. B. [Petersburg Nuclear Physics Institute, RU-188300 Gatchina (Russian Federation); Kibedi, T. [Department of Nuclear Physics, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia); Nikulin, V. K. [Ioffe Physical Technical Institute, 26 Polytekhnicheskaya, RU-194021 St. Petersburg (Russian Federation)

    2010-02-15

    A resonance-like structure of internal conversion coefficients (ICCs) at low {gamma}-ray energy (< or approx.100 keV) is studied. Our calculations revealed new, previously unknown resonance minima in the energy dependence of ICCs for the ns shells at E2-E5 transitions. The resonances are the most defined for ICCs in light and medium elements with Z < or approx. 50. It is shown that ICCs may have up to four resonances for outer shells while it has been assumed so far that only one resonance exists. Well-pronounced resonances in ICCs at E1 transition were discovered for the ns shells with n>=2 as well as for the np shells with n>=3 and the nd shells with n>=4 of all elements up to superheavy ones. Simple expressions for approximate values of the E1 resonance energy were obtained which are of importance for determination of the resonance energy range where the interpolation of ICCs taken from tables or databases may give significant errors. The occurrence of resonances in ICCs is explained by vanishing conversion matrix elements under changes of sign. The peculiarities of the behavior of the matrix elements and electron wave functions at the resonance energy are considered. Available experimental ICCs for electric transitions with energies near the expected position of resonances satisfactory agree with our calculations.

  3. ENERGY CONVERSION FOR THE TRANSITION FROM Al TO ?-Al2O3 NANOPARTICLES

    NASA Astrophysics Data System (ADS)

    Wang, Shulin; Li, Shengjuan; Xu, Bo; Jian, Dunliang; Zhu, Yufang

    2013-07-01

    We have successfully converted large volume Al particles into ?-Al2O3 nanostructures by vibration milling at room temperature and successive treatment. We show that there exist special relationships among stacking fault energy (SFE), strain energy (SRE), and surface energy (SE) of the materials, including interdependence, intercompetition, and interconversion during the phase transition. SFE and SRE perform the same changing tendency, while SE just does the opposite. However, it is not the particle size but the energy state that determines the reactivity of the materials. And it is the SE that can directly determine the physical chemical reaction and the conversion into the end product rather than SFE and SRE. When SE goes up, the material reactivity and the product yield will be enhanced; and when SE goes down, the reaction and the product yield will decay. However, the state of SE depends closely on the change tendency of the SFE and SRE. That is, when SFE and SRE goes up, SE will goes down; if SFE and SRE goes down, SE will goes up. It seems that energy conservation law may be followed in a sense in the particle system if the external input keeps constant. The work may be significant for energy conversion in nano-scale and mechanosynthesis of oxide nanoparticles.

  4. Aqueous Lithium-Iodine Solar Flow Battery for the Simultaneous Conversion and Storage of Solar Energy.

    PubMed

    Yu, Mingzhe; McCulloch, William D; Beauchamp, Damian R; Huang, Zhongjie; Ren, Xiaodi; Wu, Yiying

    2015-07-01

    Integrating both photoelectric-conversion and energy-storage functions into one device allows for the more efficient solar energy usage. Here we demonstrate the concept of an aqueous lithium-iodine (Li-I) solar flow battery (SFB) by incorporation of a built-in dye-sensitized TiO2 photoelectrode in a Li-I redox flow battery via linkage of an I3(-)/I(-) based catholyte, for the simultaneous conversion and storage of solar energy. During the photoassisted charging process, I(-) ions are photoelectrochemically oxidized to I3(-), harvesting solar energy and storing it as chemical energy. The Li-I SFB can be charged at a voltage of 2.90 V under 1 sun AM 1.5 illumination, which is lower than its discharging voltage of 3.30 V. The charging voltage reduction translates to energy savings of close to 20% compared to conventional Li-I batteries. This concept also serves as a guiding design that can be extended to other metal-redox flow battery systems. PMID:26102317

  5. High conversion efficiency, high energy terahertz pulses by optical rectification in cryogenically cooled lithium niobate.

    PubMed

    Huang, Shu-Wei; Granados, Eduardo; Huang, Wenqian Ronny; Hong, Kyung-Han; Zapata, Luis E; Kärtner, Franz X

    2013-03-01

    We demonstrate highly efficient terahertz (THz) generation by optical rectification (OR) of near-optimum pump pulses centered at 1.03 ?m in cryogenically cooled lithium niobate. Using a close to optimal pulse duration of 680 fs and a pump energy of 1.2 mJ, we report conversion efficiencies above 3.8±0.4%, which is more than an order of magnitude higher than previously reported. The results confirm the advantage of using cryogenic cooling of the lithium niobate crystal that significantly reduces the THz absorption, enabling the scaling of THz pulse energies to the millijoule level via OR. PMID:23455302

  6. A variable speed wind energy conversion scheme for connection to weak AC systems

    SciTech Connect

    Neris, A.S.; Vovos, N.A.; Giannakopoulos, G.B. [Univ. of Patras, Rion (Greece). Dept. of Electrical and Computer Engineering] [Univ. of Patras, Rion (Greece). Dept. of Electrical and Computer Engineering

    1999-03-01

    A three level control system for a variable speed wind energy conversion scheme (VSWECS) supplying a weak AC system is presented. The objective of the control strategy is to maximize energy capture and simultaneously to support the voltage of the bus where the VSWECS is connected. Using an insulated gate bipolar transistors (IGBT) inverter both control of active and reactive power supplied to the grid and reduction of harmonic distortion can be achieved. The response of the proposed scheme has been tested and evaluated in a test system using a developed computer program simulating in detail the system operation.

  7. Chapter 1.12: Solar Radiation Resource Assessment for Renewable Energy Conversion

    SciTech Connect

    Myers, D. R.

    2012-01-01

    This chapter addresses measurements, modeling, and databases of solar energy potential that may serve as fuel for solar energy conversion systems. Developing innovative designs for capturing and converting solar radiation is only one part of the equation for solar system deployment. Identifying, locating, and prospecting for the appropriate quantity and quality of solar resources to fuel these systems is critical to system designers, investors, financial backers, utilities, governments, and owner/operators. This chapter addresses the fundamentals and state of the art for measuring, modeling, and applying solar radiation resource data to meet decision-making needs.

  8. Magnetic fusion energy studies in Japan

    NASA Astrophysics Data System (ADS)

    Ogawa, M.; Tsuji-Iio, S.; Komori, A.; Kawahata, K.; Kaneko, O.; Inoue, T.; Kamada, Y.

    2007-07-01

    The primary facility for magnetic fusion energy (MFE) research in Japan is JT-60, in which DD plasma is heated up to an electron temperature of Te>10 keV with neutral beam injection (NBI) and radio frequency (RF) powers. It is noted that a normalized ?N of 2.3 was maintained for 22 s. The JT-60 team has discovered internal transport barrier (ITB) in high-beta-poloidal discharges as an additional improved confinement mechanism like a previously known edge transport barrier (ETB). The operation forming the ITB has remarkably improved the plasma confinement. The second major MFE facility is a large helical device (LHD) at National Institute for Fusion Science (NIFS). The world's largest superconducting coil system of LHD generates helical magnetic field of 3 T where the stored magnetic energy reaches 1 GJ. A quasi-stationary plasma with an electron density of 4×10 18 m -3 at a temperature of about 1 keV was sustained for 54 min with the help of ion cyclotron range of frequency (ICRF) and electron cyclotron range of frequency (ECRF). The maximum electron density so far achieved is 5×10 20 m -3 with Te˜1 keV. We report MFE programs related to International Thermonuclear Experimental Reactor (ITER).

  9. A high-efficiency magnetic component with superior caloric performance for low-profile high-density power conversion

    Microsoft Academic Search

    Willem Gerhardus Odendaal; Jose Azevedo; Gert W. Brüning; Ronald M. Wolf

    2004-01-01

    This paper describes a magnetic component structure that features both low profile and the ability to achieve very high power and energy densities. A key characteristic which enables reaching both of these objectives is the incorporation of a foil winding with a high packing density and a unique shape factor, which enhances thermal and electromagnetic performances simultaneously. Although implementation of

  10. Enhanced figure of merit in thermal to electrical energy conversion using diode structures

    NASA Astrophysics Data System (ADS)

    Hagelstein, P. L.; Kucherov, Y.

    2002-07-01

    A characterization of the electrical and thermal properties of thermoelectric diode structures indicates that the figure of merit for thermal to electrical energy conversion is significantly enhanced in our devices over thermoelectric values. Enhancements are due to current injection and blockage of the ohmic return current within the devices. The resulting device takes advantage of both thermoelectric and thermionic effects, and can be considered to be a hybrid. Experiments indicate an enhancement as high as a factor of 8 in the effective figure of merit. The best results are consistent with a conversion efficiency on the order of 35% of the Carnot limit. Enhancements have been observed in InSb and in HgCdTe, and we believe that the approach applies generally to all thermoelectric semiconductors.

  11. A solar simulator-pumped gas laser for the direct conversion of solar energy

    NASA Technical Reports Server (NTRS)

    Weaver, W. R.; Lee, J. H.

    1981-01-01

    Most proposed space power systems are comprised of three general stages, including the collection of the solar radiation, the conversion to a useful form, and the transmission to a receiver. The solar-pumped laser, however, effectively eliminates the middle stage and offers direct photon-to-photon conversion. The laser is especially suited for space-to-space power transmission and communication because of minimal beam spread, low power loss over large distances, and extreme energy densities. A description is presented of the first gas laser pumped by a solar simulator that is scalable to high power levels. The lasant is an iodide C3F7I that as a laser-fusion driver has produced terawatt peak power levels.

  12. A space-based combined thermophotovoltaic electric generator and gas laser solar energy conversion system

    NASA Astrophysics Data System (ADS)

    Yesil, Oktay

    This paper describes a spaceborne energy conversion system consisting of a thermophotovoltaic electric generator and a gas laser. As a power source for the converson, the system utilizes an intermediate blackbody cavity heated to a temperature of 2000-2400 K by concentrated solar radiation. A double-layer solar cell of GaAs and Si forms a cylindrical surface concentric to this blackbody cavity, receiving the blackbody radiation and converting it into electricity with cell conversion efficiency of 50 percent or more. If the blackbody cavity encloses a laser medium, the blackbody radiation can also be used to simultaneously pump a lasing gas. The feasibility of blackbody optical pumping at 4.3 microns in a CO2-He gas mixture was experimentally demonstrated.

  13. The alkali metal thermoelectric converter /AMTEC/ - A new direct energy conversion technology for aerospace power

    NASA Technical Reports Server (NTRS)

    Bankston, C. P.; Cole, T.; Jones, R.; Ewell, R.

    1982-01-01

    A thermally regenerative electrochemical device for the direct conversion of heat to electrical energy, the alkali metal thermoelectric converter (AMTEC), is characterized by potential efficiencies on the order of 15-40% and possesses no moving parts, making it a candidate for space power system applications. Device conversion efficiency is projected on the basis of experimental voltage vs current curves exhibiting power densities of 0.7 W/sq cm and measured electrode efficiencies of up to 40%. Preliminary radiative heat transfer measurements presented may be used in an investigation of methods for the reduction of AMTEC parasitic radiation losses. AMTEC assumes heat input and rejection temperatures of 900-1300 K and 400-800 K, respectively. The working fluid is liquid sodium, and the porous electrode employed is of molybdenum.

  14. The effect of converter efficiency on DEAP-based energy conversion: an overview and optimization method

    NASA Astrophysics Data System (ADS)

    van Kessel, Rick; Wattez, Ambroise; Bauer, Pavol

    2014-03-01

    This work presents an integral approach to the power electronic challenges that are faced in DEAP-based energy conversion, such as wide converter operating ranges and high peak-to-average ratios. It is shown that for small strain cycles, the losses in the Power Electronic Converter (PEC) due to the cyclic charging and discharging are dominant. The efficiency profile of a realistic, high-voltage modular PEC was measured and fed into an optimization algorithm. The current amplitude, phase and shape are optimized, and different cycle types are compared. With optimization results for a wide strain range, it is demonstrated that with properly adapted harvesting cycles, the overall conversion efficiency is significantly improved, especially for small strain cycles.

  15. Superconducting magnetic energy storage for electric utilities and fusion systems

    Microsoft Academic Search

    J. D. Rogers; H. J. Boenig; W. V. Hassenzahl

    1978-01-01

    Energy storage inductors, under development for load leveling and transmission line stabilization in electric utility systems and for driving magnetic confinement and plasma heating coils in fusion energy system are described. Superconducting magnetic energy storage (SMES) systems, which will store and deliver electrical energy for load leveling, peak shaving, and the stabilization of electric utility network are discussed. In the

  16. Assembly and Testing of an On-Farm Manure to Energy Conversion BMP for Animal Waste Pollution Control

    E-print Network

    Engler, Cady; Capereda, Sergio; Mukhtar, Saqib

    Report TR-366 Assembly and Testing of an On-Farm Manure to Energy Conversion BMP for Animal Water Pollution Control 1 Funding was provided by the U.S. Department of Agriculture?s Natural Resources Conservation Service through a Texas... Conservation Innovation Grant. Assembly and Testing of an On-Farm Manure to Energy Conversion BMP for Animal Water Pollution Control 2 Table of Contents List of Figures...

  17. Positronium spin conversion during collisions with Xe and its application for measuring the kinetic energy

    NASA Astrophysics Data System (ADS)

    Shibuya, Kengo; Kawamura, Yoshihiro; Saito, Haruo

    2015-06-01

    Positronium(Ps) can undergo ortho-para spin conversion reaction during Ps-Xecollisions due to spin-orbit interaction. We have investigated energy dependence of this reaction rate and found it is nearly proportional to T2.1, where T is the temperature (300-623 K), while the pick-off annihilation rate is proportional to T. The strong temperature dependence of the former annihilation rate is attributed to a nature of p-wave scattering because this reaction is forbidden in s-wave scattering. In addition, a new method for measuring Ps kinetic energy has been developed with a high resolution and a high sensitivity by utilizing the strong temperature dependence as a "thermometer." Analyzingthe obtained time evolution of Ps kinetic energy, we have determined the momentum transfer cross section during Ps-Xecollisions at a very low energy (40-60 meV) to be 12(2)×10?16 cm2.

  18. Report of feasibility study on international-cooperation in high efficient energy conversion technology

    NASA Astrophysics Data System (ADS)

    1993-03-01

    With regard to accelerated introduction of high efficient energy conversion technology to developing countries, the paper investigates the countries' thoughts of the introduction of the technology and the status of the introduction bases. The countries for survey are the Philippines, Indonesia, Malaysia and Thailand. The Philippine government expects to develop cogeneration as well as large power sources and to widen effective use of natural energy. In Indonesia, they largely expect effective use of biomass energy using Stirling engines by international cooperation and the promoted local electrification using standalone distributed fuel cells. In Malaysia, they have great expectations of the introduction of air conditioning facilities using Stirling engines and the use of standalone distributed fuel cells for promotion of local electrification. Thailand hopes for the use of Stirling engines to air conditioning systems, and the development of solar Stirling generators with solar energy as a heat source and electric vehicles.

  19. Piezoelectric coupling in energy-harvesting fluttering flexible plates : linear stability analysis and conversion efficiency

    E-print Network

    Doare, Olivier

    2011-01-01

    This paper investigates the energy harvested from the flutter of a plate in an axial flow by making use of piezoelectric materials. The equations for fully-coupled linear dynamics of the fluid-solid and electrical systems are derived. The continuous limit is then considered, when the characteristic length of the plate's deformations is large compared to the piezoelectric patches' length. The linear stability analysis of the coupled system is addressed from both a local and global point of view. Piezoelectric energy harvesting adds rigidity and damping on the motion of the flexible plate, and destabilization by dissipation is observed for negative energy waves propagating in the medium. This result is confirmed in the global analysis of fluttering modes of a finite-length plate. It is finally observed that waves or modes destabilized by piezoelectric coupling maximize the energy conversion efficiency.

  20. Toroidal constant-tension superconducting magnetic energy storage units

    DOEpatents

    Herring, J.S.

    1992-11-03

    A superconducting magnetic energy storage unit is provided in which the magnet is wound in a toroidal fashion such that the magnetic field produced is contained only within the bore of the magnet, and thus producing a very low external field. The superconducting magnet includes a coolant channel disposed through the wire. The bore of the magnet comprises a storage volume in which cryogenic coolant is stored, and this volume supplies the coolant to be delivered to the coolant channel in the magnet. 6 figs.