These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

Permanent magnet energy conversion machine with magnet mounting arrangement  

SciTech Connect

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.

Hsu, J.S.; Adams, D.J.

1999-09-14

2

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

PubMed

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

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

2014-01-01

3

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

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

4

Rare earth permanent magnets and energy conversion processes  

Microsoft Academic Search

Traditionally in magnetoelectric devices the stator has been the massive and static part of the device and the dynamic element has been a moving coil. With improvements in the volumetric efficiency of permanent magnets it is possible to rearrange magnetic circuit elements and invert devices. Rare earth permanent magnets exhibit a high magnetic moment per unit volume and have extreme

R. J. Parker

1977-01-01

5

Reduced order observer for permanent magnet synchronous generator in wind energy conversion system  

Microsoft Academic Search

This paper presents an approach to develop a simple reduced speed observer for permanent magnet synchronous generator (PMSG) in wind energy conversion system (WECS). The speed and rotor position estimation of the PMSG are obtained by only measuring phase voltage and current. Maximum wind energy extraction is achieved by running the wind turbine generator in variable-speed mode. The rotor speed

Lotfi KRICHEN; Hsan HADJ ABDALLAH; Abderrazak OUALI

2007-01-01

6

Microscopic Analysis of Energy Conversion in a 5Phase Permanent Magnet Synchronous Machine  

Microsoft Academic Search

This paper aims to characterize the behavior of both radial and tangential components of force in a 5-phase PMSM. Energy conversion has been investigated at a microscopic level and the effects of q- and d-components of current on generated torque have been investigated along with their influence on the radial vibrations. Further, magnetic field reconstruction is employed in an attempt

Mahesh Krishnamurthy; Babak Fahimi; Steven D. Pekarek

2006-01-01

7

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

SciTech Connect

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.

Janos, A.

1985-09-01

8

Optimal design of permanent magnet synchronous generator for wind energy conversion considering annual energy input and magnet volume  

Microsoft Academic Search

In this paper a multi-objective criterion function is introduced to maximize annual energy input (AEI) and minimize permanent magnet (PM) volumes in a permanent magnet synchronous generator (PMSG). First, a PMSG is designed and modeled analytically to achieve above mentioned targets. After that, effects of various generator parameters on the two above-mentioned objective functions are analyzed using this model. The

Jawad Faiz; Bashir Mahdi Ebrahimi; M. Rajabi-Sebdani; A. Khan

2009-01-01

9

Vocational-Technical Physics Project. The Alternator: I. Current Electricity, II. Magnets from Electricity, III. Electricity from Magnets, IV. Energy Conversion. Field Test Edition.  

ERIC Educational Resources Information Center

This vocational physics individualized instructional student module on the alternator consists of the four units: Current electricity, magnets from electricity, electricity from magnets, and energy conversion. Designed with a laboratory orientation, the units present explanations of the concepts and experiments. Laboratory data sheets,…

Forsyth Technical Inst., Winston-Salem, NC.

10

Direct Conversion of Energy.  

ERIC Educational Resources Information Center

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…

Corliss, William R.

11

Magnetohydrodynamics of atmospheric transients. IV. Nonplane two-dimensional analyses of energy conversion and magnetic field evolution  

SciTech Connect

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 examined by a nonplane magnetohydrodynamic (MHD) analysis. In the 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 due to the initial magnetic field, either twisted (force-free) or nontwisted (potential), is demonstrated. In both cases, of course, the field becomes non-force-free after the energy release, i.e., a flare. As in Papers I and II of this series, two initial field topologies (open vs. closed) are considered. The results show that the conversion of magnetic energy is faster for the case of the initially twisted (force-free) field in comparison with the initially untwisted (potential) field. Also, the twisted field produces a complex structure of the density enhancements. Comparison of the asymmetric topological evolution of the initially twisted magnetic fields with several white-light coronal transients (observed recently during the Solar Maximum year suggests that some preflare, magnetic topologies above the site of the energy release are nonpotential. This suggestion is based on the asymmetrial, somewhat concentric (''tennis racket'' shape), electron density enhancement obtained together with the twisted magnetic field lines in this study.

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

1982-11-01

12

On Energy Conversion Calculations  

Microsoft Academic Search

It is shown that calculations of the energy conversion from available potential energy to kinetic energy based on vertical velocities obtained by the so-called adiabatic method may lead to erroneoils results. An analysis of the method shows that it ineasures the difference between the energy conversion from available potential energy to kinctic energy, and the generation of available potential by

A. Wiin-Nielsen

1964-01-01

13

Perspectives on Permanent Magnetic Materials for Energy Conversion and Power Generation  

NASA Astrophysics Data System (ADS)

Permanent magnet development has historically been driven by the need to supply larger magnetic energy in ever smaller volumes for incorporation in an enormous variety of applications that include consumer products, transportation components, military hardware, and clean energy technologies such as wind turbine generators and hybrid vehicle regenerative motors. Since the 1960s, the so-called rare-earth "supermagnets," composed of iron, cobalt, and rare-earth elements such as Nd, Pr, and Sm, have accounted for the majority of global sales of high-energy-product permanent magnets for advanced applications. In rare-earth magnets, the transition-metal components provide high magnetization, and the rare-earth components contribute a very large magnetocrystalline anisotropy that donates high resistance to demagnetization. However, at the end of 2009, geopolitical influences created a worldwide strategic shortage of rare-earth elements that may be addressed, among other actions, through the development of rare-earth-free magnetic materials harnessing sources of magnetic anisotropy other than that provided by the rare-earth components. Materials engineering at the micron scale, nanoscale, and Angstrom scales, accompanied by improvements in the understanding and characterization of nanoscale magnetic phenomena, is anticipated to result in new types of permanent magnetic materials with superior performance.

Lewis, Laura H.; Jiménez-Villacorta, Félix

2013-01-01

14

Solar energy conversion panel  

Microsoft Academic Search

A solar energy conversion panel is provided by means of which solar energy is recovered as converted electrical energy and also thermal energy. An array of solar energy collectors direct solar energy received from the sun upon photovoltaic cells within the collectors. The photovoltaic cells convert a portion of this energy into electrical energy. The balance of the solar energy

1981-01-01

15

Evaluating Energy Conversion Efficiency  

NASA Technical Reports Server (NTRS)

Devices that convert solar radiation directly into storable chemical or electrical energy, have characteristic energy absorption spectrum; specifically, each of these devices has energy threshold. The conversion efficiency of generalized system that emcompasses all threshold devices is analyzed, resulting in family of curves for devices of various threshold energies operating at different temperatures.

Byvik, C. E.; Smith, B. T.; Buoncristiani, A. M.

1983-01-01

16

Photochemical Energy Conversion.  

ERIC Educational Resources Information Center

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)

Batschelet, William H.; George, Arnold

1986-01-01

17

Algae Harvest Energy Conversion  

Microsoft Academic Search

\\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

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

18

Wind energy conversion  

Microsoft Academic Search

Effective utilization of wind energy requires systematic studies of the sites available for the location of wind energy conversion systems and careful evaluation of the type and size of machines to be used. The present paper describes an approach currently in use for the siting of wind generators. It describes also the aerodynamic features of various types of wind machines

A. A. Fejer

1978-01-01

19

BECON, Biomass Energy CONversion  

NSDL National Science Digital Library

How is biomass transformed into a usable fuel? This article, part of a series about the future of energy, discusses the BECON (Biomass Energy CONversion) facility, located in the state of Iowa. Here students read about methods used to produce alternative fuels from biomass. Copyright 2005 Eisenhower National Clearinghouse

Project, Iowa P.

2004-01-01

20

Laser energy conversion  

NASA Technical Reports Server (NTRS)

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.

Jalufka, N. W.

1989-01-01

21

Laser energy conversion  

NASA Astrophysics Data System (ADS)

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.

Jalufka, N. W.

1989-07-01

22

Solar energy conversion.  

SciTech Connect

If solar energy is to become a practical alternative to fossil fuels, we must have efficient ways to convert photons into electricity, fuel, and heat. The need for better conversion technologies is a driving force behind many recent developments in biology, materials, and especially nanoscience. The Sun has the enormous untapped potential to supply our growing energy needs. The barrier to greater use of the solar resource is its high cost relative to the cost of fossil fuels, although the disparity will decrease with the rising prices of fossil fuels and the rising costs of mitigating their impact on the environment and climate. The cost of solar energy is directly related to the low conversion efficiency, the modest energy density of solar radiation, and the costly materials currently required. The development of materials and methods to improve solar energy conversion is primarily a scientific challenge: Breakthroughs in fundamental understanding ought to enable marked progress. There is plenty of room for improvement, since photovoltaic conversion efficiencies for inexpensive organic and dye-sensitized solar cells are currently about 10% or less, the conversion efficiency of photosynthesis is less than 1%, and the best solar thermal efficiency is 30%. The theoretical limits suggest that we can do much better. Solar conversion is a young science. Its major growth began in the 1970s, spurred by the oil crisis that highlighted the pervasive importance of energy to our personal, social, economic, and political lives. In contrast, fossil-fuel science has developed over more than 250 years, stimulated by the Industrial Revolution and the promise of abundant fossil fuels. The science of thermodynamics, for example, is intimately intertwined with the development of the steam engine. The Carnot cycle, the mechanical equivalent of heat, and entropy all played starring roles in the development of thermodynamics and the technology of heat engines. Solar-energy science faces an equally rich future, with nanoscience enabling the discovery of the guiding principles of photonic energy conversion and their use in the development of cost-competitive new technologies.

Crabtree, G. W.; Lewis, N. S. (Materials Science Division); (California Inst. of Tech.)

2008-03-01

23

Mechanochemical Energy Conversion  

ERIC Educational Resources Information Center

Summarizes the thermodynamics of macromolecular systems, including theories and experiments of cyclic energy conversion with rubber and collagen as working substances. Indicates that an early introduction into the concept of chemical potential and solution thermodynamics is made possible through the study of the cyclic processes. (CC)

Pines, E.; And Others

1973-01-01

24

Photovoltaic Energy Conversion  

E-print Network

suited to solar spectrum Poly-Si CdTe CIGS (Copper-Indium-Gallium-Selenide) Organic and Dye Make solar cells more efficient Theoretical energy conversion efficiency limit of single junction solar cell is 31% Actual efficiencies are even lower: ~20% Make solar cells cheaper "Grid Parity

Glashausser, Charles

25

Energy-mass conversion  

NSDL National Science Digital Library

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

Group, Lawrence B.

2002-01-01

26

TF and PF magnet power conversion  

SciTech Connect

This paper contains a collection of data on the Tiber II Tokamak reactors magnet power conversion. The collection of data consists of: TF coil power conversion and protection system requirements and design data, TF power conversion cost estimates, PF coil power supply data and other Tiber systems data and circuit diagram presentations.

Gorker, G.E.

1987-01-01

27

Advanced solar energy conversion  

SciTech Connect

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.

Lee, J.H.

1981-08-01

28

Flare onsets in hard and soft X-rays. [magnetic energy conversion in sun  

NASA Technical Reports Server (NTRS)

It is shown that the onset of solar flares, within about 2 min or less before the impulsive peaks, is characterized by an increase in high-energy emission at E less than 100 keV, and strong broadening of soft X-ray lines characteristic of the 10-million-K plasma already present at this stage. The observations are interpreted in terms of the early signature of energy release, during a phase preceding the instability that leads to strong particle acceleration.

Machado, Marcos E.; Orwig, Larry E.; Antonucci, Ester

1986-01-01

29

Conversion of solar energy into electricity  

Microsoft Academic Search

The four main methods used for the direct conversion of solar energy into electricity are related to photovoltaic power conversion, photoemissive power conversion, photogalvanic power conversion, and photomagnetic power conversion. Indirect conversion methods involving a heat stage are also considered, taking into account the conversion of solar energy into heat, the conversion of solar heat directly into electricity, and the

M. A. Kettani

1977-01-01

30

Instantaneous torque ripple control and maximum power extraction in a permanent magnet reluctance generator driven wind energy conversion system  

Microsoft Academic Search

A usual wind energy conversion system (WECS) suffers from significant amount of torque ripples even if the wind velocity remains constant. These torque ripples propagate mechanical stress in the turbine-generator drive train and may eventually lead to the failure of its various components. This research paper presents a unified control strategy which yields maximum power from WECS while minimizing the

Erkan Sunan; Kazmi Syed Muhammad Raza; Hiroki Goto; Hai-Jiao Guo; O. Ichinokur

2010-01-01

31

Oscillating wind energy conversion systems  

Microsoft Academic Search

The oscillating cable type wind energy conversion system and the oscillating vane and the oscillating wind are addressed. The advantages and disadvantages of each type of system are evaluated, and each is compared with a conventional rotating element wind energy conversion device. It appears unlikely that any of the oscillating element concepts can compete with the present generation of conventional

P. South; R. Mitchell

1983-01-01

32

Review of betavoltaic energy conversion  

Microsoft Academic Search

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

Larry C. Olsen

1993-01-01

33

Energy conversion and storage program  

NASA Astrophysics Data System (ADS)

The Energy Conversion and Storage Program applies chemical and chemical engineering 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 storage; (4) characterization of complex chemical processes; and (5) the application of novel materials for energy conversion and transmission. Projects focus on transport-process principles, chemical kinetics, thermodynamics, separation processes, organic and physical chemistry, and advanced methods of analysis. The following five areas are discussed: electrochemical energy storage and conversion; microstructured materials; biotechnology; fossil fuels; and high temperature superconducting processing. Papers have been processed separately for inclusion on the data base.

1990-12-01

34

Energy Conversion and Storage Program  

NASA Astrophysics Data System (ADS)

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, separation processes, organic and physical chemistry, novel materials, and advanced methods of analysis.

Cairns, E. J.

1994-06-01

35

Photovoltaic conversion of solar energy  

Microsoft Academic Search

The volume outlines the principles, techniques, and possibilities of solar energy use through photovoltaic conversion, and also develops a strategy for the future, which may help to improve Spain's energy situation. The document covers the main components of a photovoltaic system, cells and panels, energy storage, batteries, remote uses, cost problems, marketing possibilities, solar energy activities in other countries, and

P. Pezuela; F. Ruedo

1981-01-01

36

Plasmonic nanorectennas for energy conversion  

Microsoft Academic Search

There is renewed interest in using rectennas (consisting of an antenna coupled to a rectifying diode) for energy conversion applications. Progress in nanofabrication has enabled nanoscale devices to be fabricated, such that \\

Richard Osgood III; Joel B. Carlson; Brian R. Kimball; David P. Ziegler; James R. Welch; Lauren E. Belton; Gustavo E. Fernandes; Zhijun Liu; Jimmy Xu

2009-01-01

37

Solar energy conversion apparatus  

Microsoft Academic Search

Apparatus is disclosed for converting solar energy to useful energy principally for home use. The apparatus provides a complete system for receiving solar energy over a large area, e.g. 1,000 square feet; concentrating the energy; and directing the energy toward a target of a few square feet at an extremely high temperature. The receiving, concentrating and transmitting apparatus consists of

Thompson

1983-01-01

38

Energy Conversion and Storage Program  

NASA Astrophysics Data System (ADS)

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.

Cairns, E. J.

1993-06-01

39

Energy conversion system  

SciTech Connect

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.

Wang, F.E.

1981-06-30

40

Pyroelectric energy conversion: Optimization principles  

Microsoft Academic Search

In the framework of microgenerators, we present in this paper the key points for energy harvesting from temperature using ferroelectric materials. Thermoelectric devices profit from temperature spatial gradients, whereas ferroelectric materials require temporal fluctuation of temperature, thus leading to different applications targets. Ferroelectric materials may harvest perfectly the available thermal energy whatever the materials properties (limited by Carnot conversion efficiency)

Gael Sebald; Elie Lefeuvre; Daniel Guyomar

2008-01-01

41

Energy conversion and storage program  

NASA Astrophysics Data System (ADS)

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 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. Topics include identification of new electrochemical couples for advanced rechargeable batteries, improvements in battery and fuel-cell materials, and the establishment of engineering principles applicable to electrochemical energy storage and conversion. 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 waste streams from synfuel plants and coal gasifiers. Other research projects seek to identify and characterize the constituents of liquid fuel-system streams and to devise energy-efficient means for their separation. Materials Applications research includes the evaluation of the properties of advanced materials, as well as the development of novel preparation techniques. For example, the use of advanced techniques, such as sputtering and laser ablation, are being used to produce high-temperature superconducting films.

Cairns, E. J.

1992-03-01

42

Energy Conversion and Storage Program  

SciTech Connect

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 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. Topics include identification of new electrochemical couples for advanced rechargeable batteries, improvements in battery and fuel-cell materials, and the establishment of engineering principles applicable to electrochemical energy storage and conversion. 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 waste streams from synfuel plants and coal gasifiers. Other research projects seek to identify and characterize the constituents of liquid fuel-system streams and to devise energy-efficient means for their separation. Materials Applications research includes the evaluation of the properties of advanced materials, as well as the development of novel preparation techniques. For example, the use of advanced techniques, such as sputtering and laser ablation, are being used to produce high-temperature superconducting films.

Cairns, E.J.

1992-03-01

43

Energy conversion in the coronal plasma  

NASA Technical Reports Server (NTRS)

Solar and stellar X-ray emission are the observed waste products of the interplay between magnetic fields and the motion of stellar plasma. Theoretical understanding of the process of coronal heating is of utmost importance, since the high temperature is what defines the corona in the first place. Most of the research described deals with the aspects of the several rivalling theories for coronal heating. The rest of the papers deal with processes of energy conversion related to flares.

Martens, P. C. H.

1986-01-01

44

Solar energy conversion.  

SciTech Connect

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.

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

2007-03-01

45

Review of betavoltaic energy conversion  

NASA Technical Reports Server (NTRS)

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.

Olsen, Larry C.

1993-01-01

46

Review of betavoltaic energy conversion  

NASA Astrophysics Data System (ADS)

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.

Olsen, Larry C.

1993-05-01

47

Demonstrating Energy Conversion with Piezoelectric Crystals and a Paddle Fan  

NASA Astrophysics Data System (ADS)

A simple energy conversion system—particularly, the conversion of mechanical energy into electrical energy by using shaker flashlights—has recently been presented. This system uses hand generators, consisting of a magnet in a tube with a coil wrapped around it, and acts as an ac source when the magnet passes back and forth through the coil. Additionally, this system includes an LED, a capacitor, a switch, and a full-wave bridge rectifier. We were inspired by this work to design a simpler demonstrator made for teaching energy conversion concepts to science students using piezoelectric material.

Rakbamrung, Prissana; Putson, Chatchai; Muensit, Nantakan

2014-02-01

48

Electrochemistry for Energy Conversion  

NASA Astrophysics Data System (ADS)

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.

O'Hayre, Ryan

2010-10-01

49

Energy conversion using thermoacoustic devices  

Microsoft Academic Search

Thermoacoustic engines offer the possibility for simple and efficient energy conversion devices. They can be prime movers where heat produces sound or heat pumps and refrigerators where sound pumps heat. An important element in such engines is the secondary thermodynamic medium, the stack which provide the phasing between heat transfer and pressure changes at acoustical frequencies. Other elements are a

O. G. Symko

1999-01-01

50

Plasmonic nanorectennas for energy conversion  

NASA Astrophysics Data System (ADS)

There is renewed interest in using rectennas (consisting of an antenna coupled to a rectifying diode) for energy conversion applications. Progress in nanofabrication has enabled nanoscale devices to be fabricated, such that "nanoantennas" exist that resonate at visible/near-infrared (vis/nir) wavelengths, and ultrafast "nanodiodes" exist that can rectify vis/nir frequencies (above 1014 Hz). Photon energies are so high at these frequencies that existing theories of diode responsivity may not apply, justifying new simulations and experiments. We present modeling and experiments of nanoantenna-coupled nanodiodes, such as metal-insulator-metal structures, and discuss how our findings influence models of energy conversion in these structures. We simulate and measure the properties of potential nanorectennas such as gold nanowires on ultrathin insulators.

Osgood, Richard, III; Carlson, Joel B.; Kimball, Brian R.; Ziegler, David P.; Welch, James R.; Belton, Lauren E.; Fernandes, Gustavo E.; Liu, Zhijun; Xu, Jimmy

2009-08-01

51

Conversion of Electromagnetic into Acoustic Energy via Indium Films  

Microsoft Academic Search

Transverse acoustic waves were generated electromagnetically at 9 GHz using thin indium films on silicon substrates. We report measurements of the conversion efficiency alpha of electromagnetic into acoustic energy as a function of temperature, magnetic field, and microwave power. The highest conversion efficiency found above the superconducting transition temperature Tc of indium was 5×10-5 comparable to that of quartz transducers.

A. Zemel; Y. Goldstein

1973-01-01

52

Materials for thermoelectric energy conversion  

NASA Technical Reports Server (NTRS)

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.

Wood, C.

1988-01-01

53

Pyroelectric energy conversion: optimization principles.  

PubMed

In the framework of microgenerators, we present in this paper the key points for energy harvesting from temperature using ferroelectric materials. Thermoelectric devices profit from temperature spatial gradients, whereas ferroelectric materials require temporal fluctuation of temperature, thus leading to different applications targets. Ferroelectric materials may harvest perfectly the available thermal energy whatever the materials properties (limited by Carnot conversion efficiency) whereas thermoelectric material's efficiency is limited by materials properties (ZT figure of merit). However, it is shown that the necessary electric fields for Carnot cycles are far beyond the breakdown limit of bulk ferroelectric materials. Thin films may be an excellent solution for rising up to ultra-high electric fields and outstanding efficiency. Different thermodynamic cycles are presented in the paper: principles, advantages, and drawbacks. Using the Carnot cycle, the harvested energy would be independent of materials properties. However, using more realistic cycles, the energy conversion effectiveness remains dependent on the materials properties as discussed in the paper. A particular coupling factor is defined to quantify and check the effectiveness of pyroelectric energy harvesting. It is defined similarly to an electromechanical coupling factor as k2=p2theta0/(epsilontheta33cE), where p, theta0, epsilontheta33, cE are pyroelectric coefficient, maximum working temperature, dielectric permittivity, and specific heat, respectively. The importance of the electrothermal coupling factor is shown and discussed as an energy harvesting figure of merit. It gives the effectiveness of all techniques of energy harvesting (except the Carnot cycle). It is finally shown that we could reach very high efficiency using 1110.75Pb(Mg1/3Nb2/3)-0.25PbTiO3 single crystals and synchronized switch harvesting on inductor (almost 50% of Carnot efficiency). Finally, practical implementation key points of pyroelectric energy harvesting are presented showing that the different thermodynamic cycles are feasible and potentially effective, even compared to thermoelectric devices. PMID:18407845

Sebald, Gael; Lefeuvre, Elie; Guyomar, Daniel

2008-03-01

54

Radiation energy conversion in space  

NASA Technical Reports Server (NTRS)

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' on earth. The Solares space-energy-system concept, designed for providing a large fraction of the world's energy needs at costs comparable to those of future coal/nuclear alternative, is considered, as are subsystems for improving the economics of the solar power satellite. A concept proposing the use of relativistic-electron-storage rings for electron-beam energy transmission and storage, and a report on the production of a high temperature plasma with concentrated solar radiation are taken into account. Laser-conversion systems, including the direct-solar-pumped space laser, and the telec-powered spacecraft, are discussed.

Billman, K. W.

1979-01-01

55

Energy conversion at the Earth's magnetopause using single and multispacecraft methods  

E-print Network

a small statistical data set, where we investigate energy conversion at the magnetopause using Cluster controlled by the solar wind and the interplanetary magnetic field (IMF). The energy transfer and conversion. In the tail lobe generator, the energy conversion occurs at the expense of solar wind kinetic energy sweeping

Bergen, Universitetet i

56

Ocean thermal-energy conversion  

NASA Astrophysics Data System (ADS)

The principles underlying ocean thermal-energy conversion (OTEC) are reviewed, and a schematic layout of a system is included. The two systems currently under study, the open system and the closed system, are described. The prospect now, it is noted, is that OTEC plants will not be commercially viable on a widespread basis, even in the tropics. This is especially true of the large-scale plants that have been envisioned. A strong possibility is seen, however, that smaller plants, generating about 40 megawatts of electrical power, can survive commercially. The following conditions would favor their success: placement on land rather than at sea; placement in areas (such as islands) where alternative energy supplies are at a premium; and designing the plant to operate in conjunction with either an aquaculture or a desalination plant.

Ford, G.; Niblett, C.; Walker, L.

1983-03-01

57

Electrodynamic tethers for energy conversion  

NASA Technical Reports Server (NTRS)

Conductive tethers have been proposed as a new method for converting orbital mechanical energy into electrical power for use on-board a satellite (generator mode) or conversely (motor mode) as a method of providing electric propulsion using electrical energy from the satellite. The operating characteristics of such systems are functionally dependent on orbit altitude and inclination. Effects of these relationships are examined to determine acceptable regions of application. To identify system design considerations, a specific set of system performance goals and requirements are selected. The case selected is for a 25 kW auxiliary power system for use on Space Station. Appropriate system design considerations are developed, and the resulting system is described.

Nobles, W.

1986-01-01

58

Clean Fossil Energy Conversion Processes  

NASA Astrophysics Data System (ADS)

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.

Fan, L.-S.

2007-03-01

59

Magnetic Materials in sustainable energy  

NASA Astrophysics Data System (ADS)

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.

Gutfleisch, Oliver

2012-02-01

60

Energy conversion efficiency during optical breakdown  

Microsoft Academic Search

The efficiency of optical to acoustical energy conversion during laser-induced optical breakdown has been examined. A point-explosion model has been studied to determine the value of laser-induced shock wave energy. The influence of incoming laser-pulse energy on conversion efficiency has been studied for several absorber materials.

Ladislav Grad; Janez Diaci; Janez Mozina

1991-01-01

61

Biological Solar Energy Conversion and U.S. Energy Policy  

ERIC Educational Resources Information Center

Surveys energy consumption in the United States and explores the possibility of increasing the amount of energy obtained from biomass conversion (biologically produced energy). Economic and environmental concerns of biomass conversion processes are discussed. (CP)

Pimentel, David; And Others

1978-01-01

62

HIGH ENERGY PERMANENT MAGNETS BASED ON NdFeB ALLOYS, WITH APPLICATIONS IN SYNCHRONAL MICRO GENERATORS FOR HYDRO ELECTRICAL CONVERSION  

Microsoft Academic Search

The paper presents some aspects regarding design, realization and technical characteristics of high energy permanent magnets based on NdFeB alloys. Also, the main processes for calculating field structures for magnetic circuits are presented. The paper is focused on some specific devices, developed in INCDIE ICPE- CA, consisting in electric synchronal micro generators with excitation through permanent magnets based on NdFeB

Stancu Nicolae; Gheorghe Mihai; Mitrea Sorina

63

Photon Splitting and Pair Conversion in Strong Magnetic Fields  

SciTech Connect

The magnetospheres of neutron stars provide a valuable testing ground for as-yet unverified theoretical predictions of quantum electrodynamics (QED) in strong electromagnetic fields. Exhibiting magnetic field strengths well in excess of a TeraGauss, such compact astrophysical environments permit the action of exotic mechanisms that are forbidden by symmetries in field-free regions. Foremost among these processes are single-photon pair creation, where a photon converts to an electron-positron pair, and magnetic photon splitting, where a single photon divides into two of lesser energy via the coupling to the external field. The pair conversion process is exponentially small in weak fields, and provides the leading order contribution to vacuum polarization. In contrast, photon splitting possesses no energy threshold and can operate in kinematic regimes where the lower order pair conversion is energetically forbidden. This paper outlines some of the key physical aspects of these processes, and highlights their manifestation in neutron star magnetospheres. Anticipated observational signatures include profound absorption turnovers in pulsar spectra at gamma-ray wavelengths. The shapes of these turnovers provide diagnostics on the possible action of pair creation and the geometrical locale of the photon emission region. There is real potential for the first confirmation of strong field QED with the new GLAST gamma-ray mission, recently launched by NASA in June 2008. The suppression of pair creation by photon splitting and its implications for pulsars are also discussed.

Baring, Matthew G. [Rice University, Department of Physics and Astronomy-MS 108, P. O. Box 1892, Houston, Texas 77251 (United States)

2008-10-17

64

Photon Splitting and Pair Conversion in Strong Magnetic Fields  

NASA Astrophysics Data System (ADS)

The magnetospheres of neutron stars provide a valuable testing ground for as-yet unverified theoretical predictions of quantum electrodynamics (QED) in strong electromagnetic fields. Exhibiting magnetic field strengths well in excess of a TeraGauss, such compact astrophysical environments permit the action of exotic mechanisms that are forbidden by symmetries in field-free regions. Foremost among these processes are single-photon pair creation, where a photon converts to an electron-positron pair, and magnetic photon splitting, where a single photon divides into two of lesser energy via the coupling to the external field. The pair conversion process is exponentially small in weak fields, and provides the leading order contribution to vacuum polarization. In contrast, photon splitting possesses no energy threshold and can operate in kinematic regimes where the lower order pair conversion is energetically forbidden. This paper outlines some of the key physical aspects of these processes, and highlights their manifestation in neutron star magnetospheres. Anticipated observational signatures include profound absorption turnovers in pulsar spectra at gamma-ray wavelengths. The shapes of these turnovers provide diagnostics on the possible action of pair creation and the geometrical locale of the photon emission region. There is real potential for the first confirmation of strong field QED with the new GLAST gamma-ray mission, recently launched by NASA in June 2008. The suppression of pair creation by photon splitting and its implications for pulsars are also discussed.

Baring, Matthew G.

2008-10-01

65

Photon Splitting and Pair Conversion in Strong Magnetic Fields  

E-print Network

The magnetospheres of neutron stars provide a valuable testing ground for as-yet unverified theoretical predictions of quantum electrodynamics (QED) in strong electromagnetic fields. Exhibiting magnetic field strengths well in excess of a TeraGauss, such compact astrophysical environments permit the action of exotic mechanisms that are forbidden by symmetries in field-free regions. Foremost among these processes are single-photon pair creation, where a photon converts to an electron-positron pair, and magnetic photon splitting, where a single photon divides into two of lesser energy via the coupling to the external field. The pair conversion process is exponentially small in weak fields, and provides the leading order contribution to vacuum polarization. In contrast, photon splitting possesses no energy threshold and can operate in kinematic regimes where the lower order pair conversion is energetically forbidden. This paper outlines some of the key physical aspects of these processes, and highlights their manifestation in neutron star magnetospheres. Anticipated observational signatures include profound absorption turnovers in pulsar spectra at gamma-ray wavelengths. The shapes of these turnovers provide diagnostics on the possible action of pair creation and the geometrical locale of the photon emission region. There is real potential for the first confirmation of strong field QED with the new GLAST mission, to be launched by NASA in 2008. Suppression of pair creation by photon splitting and its implications for pulsars is also discussed.

Matthew G. Baring

2008-04-05

66

Assessment of ocean thermal energy conversion  

E-print Network

Ocean thermal energy conversion (OTEC) is a promising renewable energy technology to generate electricity and has other applications such as production of freshwater, seawater air-conditioning, marine culture and chilled-soil ...

Muralidharan, Shylesh

2012-01-01

67

Compact harsh environment energy conversion systems  

NASA Astrophysics Data System (ADS)

The quest for energy is leading the industry into drilling deeper wells. Typically, a temperature gradient of 1°C/150 ft can be expected, with bottom hole temperatures reaching beyond 200°C in many areas of the world. Moreover, the increased recovery benefits and cost reductions possible with the use of horizontal and multilateral wells has triggered a need for higher power energy conversion systems in bottom hole assemblies, such as rotary steerable tools and downhole tractors. The concepts developed throughout this work address some of these new needs. This research investigated improvements, novel solutions and considerations that will lead to significant advantages in terms of reliability, extended temperature operation, increased power capability and reduced size and cost of compact harsh environment energy conversion systems. Improvements to both the electromechanical subsystem and the power electronic subsystem are introduced. Air gap viscous losses were shown to a have a significant effect on the optimal design of submersible PM (permanent magnet) machines, and a design procedure to account for this loss component in the design was developed. The application of a dual winding exterior rotor PM machine in a downhole environment enabled a significant increase in the application's torque capability, provided protection against generator winding over voltage, and reduced parts count. Comprehensive switching device qualification, testing, and simulation lead to a simple failure mitigation technique for the operation of the most suitable devices at elevated temperature. A flying capacitor multilevel inverter was then successfully constructed and temperature tested. A novel motor drive concept suited for elevated temperature oil filled environment applications concluded the research.

Ahmed, Shehab

68

Energy Conversion & Storage Program, 1993 annual report  

SciTech Connect

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.

Cairns, E.J.

1994-06-01

69

Energy Conversion in Natural and Artificial Photosynthesis  

PubMed Central

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

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

2010-01-01

70

Hybrid staging of geothermal energy conversion process  

SciTech Connect

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)

Steidel, R.F. Jr.

1984-05-07

71

Second NASA Conference on Laser Energy Conversion  

NASA Technical Reports Server (NTRS)

The possible transmission of high power laser beams over long distances and their conversion to thrust, electricity, or other useful forms of energy is considered. Specific topics discussed include: laser induced chemistry; developments in photovoltaics, including modification of the Schottky barrier devices and generation of high voltage emf'sby laser radiation of piezoelectric ceramics; the thermo electronic laser energy converter and the laser plasmadynamics converters; harmonic conversion of infrared laser radiation in molecular gases; and photon engines.

Billman, K. W. (editor)

1976-01-01

72

Thermionic energy conversion technology - Present and future  

NASA Technical Reports Server (NTRS)

Aerospace and terrestrial applications of thermionic direct energy conversion and advances in direct energy conversion (DEC) technology are surveyed. Electrode materials, the cesium plasma drop (the difference between the barrier index and the collector work function), DEC voltage/current characteristics, conversion efficiency, and operating temperatures are discussed. Attention is centered on nuclear reactor system thermionic DEC devices, for in-core or out-of-core operation. Thermionic fuel elements, the radiation shield, power conditions, and a waste heat rejection system are considered among the thermionic DEC system components. Terrestrial applications include topping power systems in fossil fuel and solar power generation.

Shimada, K.; Morris, J. F.

1977-01-01

73

Thermionic Energy Conversion (TEC) topping thermoelectrics  

NASA Technical Reports Server (NTRS)

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.

Morris, J. F.

1981-01-01

74

Photoelectrochemical cells - Conversion of intense optical energy  

NASA Technical Reports Server (NTRS)

Conversion of optical energy to chemical energy and/or electrical energy using wet photoelectrochemical cells is described. Emphasis is on (1) the photoelectrolysis of H2O to H2 and O2 using cells having n-type semiconductor photoelectrodes fabricated from TiO2, SnO2, SrTiO3, KTaO3, and KTa(0.77)Nb(0.23)O3, and (2) the conversion of light to electrical energy using CdSe- and CdS-based cells with polysulfide electrolytes.

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

1976-01-01

75

Photoelectrochemical cells - Conversion of intense optical energy  

Microsoft Academic Search

Conversion of optical energy to chemical energy and\\/or electrical energy using wet photoelectrochemical cells is described. Emphasis is on (1) the photoelectrolysis of H2O to H2 and O2 using cells having n-type semiconductor photoelectrodes fabricated from TiO2, SnO2, SrTiO3, KTaO3, and KTa(0.77)Nb(0.23)O3, and (2) the conversion of light to electrical energy using CdSe- and CdS-based cells with polysulfide electrolytes.

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

1976-01-01

76

Magnetic Materials Suitable for Fission Power Conversion in Space Missions  

NASA Technical Reports Server (NTRS)

Terrestrial fission reactors use combinations of shielding and distance to protect power conversion components from elevated temperature and radiation. Space mission systems are necessarily compact and must minimize shielding and distance to enhance system level efficiencies. Technology development efforts to support fission power generation scenarios for future space missions include studying the radiation tolerance of component materials. The fundamental principles of material magnetism are reviewed and used to interpret existing material radiation effects data for expected fission power conversion components for target space missions. Suitable materials for the Fission Power System (FPS) Project are available and guidelines are presented for bounding the elevated temperature/radiation tolerance envelope for candidate magnetic materials.

Bowman, Cheryl L.

2012-01-01

77

Electromagnetic wave energy conversion research  

NASA Technical Reports Server (NTRS)

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.

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

1975-01-01

78

SPS Energy Conversion Power Management Workshop  

NASA Astrophysics Data System (ADS)

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.

1980-06-01

79

SPS Energy Conversion Power Management Workshop  

NASA Technical Reports Server (NTRS)

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.

1980-01-01

80

Energy Forms, States and Conversions  

NSDL National Science Digital Library

Students participate in many demonstrations during the first day of this lesson to learn basic concepts related to the forms and states of energy. This knowledge is then applied the second day as students assess various everyday objects to determine what forms of energy are transformed to accomplish the object's intended task. Students use block diagrams to illustrate the form and state of energy flowing into and out of the process.

Office Of Educational Partnerships

81

Iron disulfide for solar energy conversion  

Microsoft Academic Search

Pyrite (Eg = 0.95 eV) is being developed as a solar energy material due to its environmental compatibility and its very high light absorption coefficient. A compilation of material, electronic and interfacial chemical properties is presented, which is considered relevant for quantum energy conversion. In spite of intricate problems existing within material chemistry, high quantum efficiencies for photocurrent generation (Eta

A ENNAOUI; S FIECHTER; C PETTENKOFER; N ALONSOVANTE; K BUKER; M BRONOLD; C HOPFNER; H TRIBUTSCH

1993-01-01

82

Acoustoelectric energy conversion in n-InSb  

Microsoft Academic Search

Acoustoelectric energy conversion in n-type InSb has been investigated. Electromagnetic radiation is observed at 77°K when the externally injected acoustic wave arrives at the end of a sample. The frequency of the radiation is the same as that of the acoustic wave. Application of an electric field enhances its intensity, and a transverse magnetic field also affects it. Dependence of

T. Aoki; F. Ogawa; I. Naito; T. Arizumi

1973-01-01

83

Energy conversion & storage program. 1995 annual report  

SciTech Connect

The 1995 annual report discusses laboratory activities in the Energy Conversion and Storage (EC&S) Program. The report is divided into three categories: electrochemistry, chemical applications, and material applications. Research performed in each category during 1995 is described. Specific research topics relate to the development of high-performance rechargeable batteries and fuel cells, the development of high-efficiency thermochemical processes for energy conversion, the characterization of new chemical processes and complex chemical species, and the study and application of novel materials related to energy conversion and transmission. Research projects focus on transport-process principles, chemical kinetics, thermodynamics, separation processes, organic and physical chemistry, novel materials and deposition technologies, and advanced methods of analysis.

Cairns, E.J.

1996-06-01

84

Energy from Biomass for Conversion of Biomass  

NASA Astrophysics Data System (ADS)

Along with estimates of minimum energy required by steam explosion pre-treatment of biomass some general problems concerning biomass conversion into chemicals, materials, and fuels are discussed. The energy necessary for processing biomass by steam explosion auto-hydrolysis is compared with the heat content of wood and calculated in terms of the amount of saturated steam consumed per unit mass of the dry content of wood biomass. The fraction of processed biomass available for conversion after steam explosion pre-treatment is presented as function of the amount of steam consumed per unit mass of the dry content of wood. The estimates based on a simple model of energy flows show the energy required by steam explosion pre-treatment of biomass being within 10% of the heat content of biomass - a realistic amount demonstrating that energy for the process can be supplied from a reasonable proportion of biomass used as the source of energy for steam explosion pre-treatment.

Abolins, J.; Gravitis, J.

2009-01-01

85

US energy conversion and use characteristics  

SciTech Connect

The long-range goal of the Energy Conversion and Utilization Technology (ECUT) Program is to enhance energy productivity in all energy-use sectors by supporting research on improved efficiency and fuel switching capability in the conversion and utilization of energy. Regardless of the deficiencies of current information, a summary of the best available energy-use information is needed now to support current ECUT program planning. This document is the initial draft of this type of summary and serves as a data book that will present current and periodically updated descriptions of the following aspects of energy use: gross US energy consumption in each major energy-use sector; energy consumption by fuel type in each sector; energy efficiency of major equipment/processes; and inventories, replacement rates, and use patterns for major energy-using capital stocks. These data will help the ECUT program staff perform two vital planning functions: determine areas in which research to improve energy productivity might provide significant energy savings or fuel switching and estimate the actual effect that specific research projects may have on energy productivity and conservation. Descriptions of the data sources and examples of the uses of the different types of data are provided in Section 2. The energy-use information is presented in the last four sections; Section 3 contains general, national consumption data; and Sections 4 through 6 contain residential/commercial, industrial, and transportation consumption data, respectively. (MCW)

Imhoff, C.H.; Liberman, A.; Ashton, W.B.

1982-02-01

86

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

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;…

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

87

Energy Conversion: Nano Solar Cell  

NASA Astrophysics Data System (ADS)

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.

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

2009-09-01

88

Homopolar Transformer for Conversion of Electrical Energy.  

National Technical Information Service (NTIS)

The DC voltage of electrical energy applied to a homopolar machine, is converted by transformer windings in response to rotor rotation within the magnetic field of the homopolar machine, to a different voltage level for supply to a load.

R. C. Smith

1997-01-01

89

Carbon aerogel electrodes for direct energy conversion  

Microsoft Academic Search

A direct energy conversion device, such as a fuel cell, using carbon aerogel electrodes, wherein the carbon aerogel is loaded with a noble catalyst, such as platinum or rhodium and soaked with phosphoric acid, for example. A separator is located between the electrodes, which are placed in a cylinder having plate current collectors positioned adjacent the electrodes and connected to

Steven T. Mayer; James L. Kaschmitter; Richard W. Pekala

1997-01-01

90

Carbon aerogel electrodes for direct energy conversion  

Microsoft Academic Search

A direct energy conversion device, such as a fuel cell, using carbon aerogel electrodes is described, wherein the carbon aerogel is loaded with a noble catalyst, such as platinum or rhodium and soaked with phosphoric acid, for example. A separator is located between the electrodes, which are placed in a cylinder having plate current collectors positioned adjacent the electrodes and

S. T. Mayer; J. L. Kaschmitter; R. W. Pekala

1997-01-01

91

Efficiency of energy conversion in Nitinol  

Microsoft Academic Search

The efficiency of the energy conversion in Nitinol was investigated experimentally. An electronically controlled Cycle Simulator subjected a single Nitinol wire element to the stress strain temperature cycles corresponding to a specific thermodynamic cycle. The test parameters, which were varied singly or in combination, included various stress levels, stress rates, percent of elongation of the wire, temperature levels, heating and

R. D. Kopa

1979-01-01

92

Novel Nuclear Powered Photocatalytic Energy Conversion  

Microsoft Academic Search

The University of Massachusetts Lowell Radiation Laboratory (UMLRL) is involved in a comprehensive project to investigate a unique radiation sensing and energy conversion technology with applications for in-situ monitoring of spent nuclear fuel (SNF) during cask transport and storage. The technology makes use of the gamma photons emitted from the SNF as an inherent power source for driving a GPS-class

John R. White; Douglas Kinsmen; Thomas M. Regan; Leo M. Bobek

2005-01-01

93

Comments on TEC trends. [Thermionic Energy Conversion  

NASA Technical Reports Server (NTRS)

The paper comments on published and projected thermionic-energy-conversion (TEC) performance trends. This commentary includes graphs and an appendix relating TEC performance parameters, plots of predicted and actual TEC trends, a figure relating projected cost of electricity to overall efficiency for TEC topping, and a discussion of the implications of these relationships.

Morris, J. F.

1979-01-01

94

Power conversion mechanisms for wave energy  

Microsoft Academic Search

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

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

2002-01-01

95

The power of thermionic energy conversion  

SciTech Connect

This article is a technology assessment of thermionic energy conversion. The topics of the article include current thermionic programs, application to planned military and civilian space missions, USA and former Soviet Union cooperation in thermionic developmental activities, the Topaz program, types of converters, emitter developments, demonstrating readiness, and ionization media developments.

Ramalingam, M.L. (UES Inc., Dayton, OH (United States)); Young, T.J. (Air Force Wright Lab., Wright-Patterson AFB, OH (United States). Aerospace Power Div.)

1993-09-01

96

Approaches for biological and biomimetic energy conversion  

PubMed Central

This article highlights areas of research at the interface of nanotechnology, the physical sciences, and biology that are related to energy conversion: specifically, those related to photovoltaic applications. Although much ongoing work is seeking to understand basic processes of photosynthesis and chemical conversion, such as light harvesting, electron transfer, and ion transport, application of this knowledge to the development of fully synthetic and/or hybrid devices is still in its infancy. To develop systems that produce energy in an efficient manner, it is important both to understand the biological mechanisms of energy flow for optimization of primary structure and to appreciate the roles of architecture and assembly. Whether devices are completely synthetic and mimic biological processes or devices use natural biomolecules, much of the research for future power systems will happen at the intersection of disciplines. PMID:16567648

LaVan, David A.; Cha, Jennifer N.

2006-01-01

97

Evidence of the theoretically predicted seismo-magnetic conversion  

Microsoft Academic Search

Seismo-electromagnetic phenomena in porous media arise from seismic wave-induced fluid motion in the pore space, which perturbs the equilibrium of the electric double layer. This paper describes with details the original experimental apparatus built within the ultra-shielded chamber of the Low Noise Underground Laboratory of Rustrel (France). We measured seismo-magnetic conversions in moist sand using two induction magnetometers, and a

Clarisse Bordes; Laurence Jouniaux; Stéphane Garambois; Michel Dietrich; Jean-Pierre Pozzi; Stéphane Gaffet

2008-01-01

98

Conversion of radiant light energy in photobioreactors  

SciTech Connect

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 organisms. The local volumetric rate of radiant light energy absorbed, which appears in the dissipation function as an irreversible term, is calculated for monodimensional approximations providing analytical solutions and for general tridimensional equations requiring the solution of a new numerical algorithm. Solutions for the blue-green alga Spirulina platensis cultivated in photoreactors with different geometries and light energy inputs are compared. Thermodynamic efficiency of the photosynthesis is calculated. The highest value of 15% found for low radiant energy absorption rates corresponds to a maximum quantum yield in the reactor.

Cornet, J.F.; Dussap, C.G.; Gros, J.B. (Univ. Blase Pascal, Aubiere (France). Lab. de Genie Chimique Biologique)

1994-06-01

99

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

E-print Network

- sinusoidal hack emf motors are excited with sinusoidal current mounted permanent-magnet to address these Keywords: permanent-magnet motors, optimization, torque ripple, issues, For example, in [4 Strategies for Surface-MountedPermanent-Magnet SynchronousMachine Drives P.L. Chapman,Member S

Chapman, Patrick

100

An efficient experimental method for high power direct drive wind energy conversion systems  

Microsoft Academic Search

Because of energy shortage and environment pollution, the renewable energy, especially wind energy has become more and more considerable all over the world. Direct drive wind energy conversion systems based on multipole permanent magnet synchronous generator (PMSG) have some advantages such as no gearbox, high power density, high precision and easy to control. In our research project, a 2MW direct

Weihao Hu; Yue Wang; Weizheng Yao; Jinlong Wu; Hailong Zhang; Zhaoan Wang

2008-01-01

101

The power of thermionic energy conversion  

NASA Astrophysics Data System (ADS)

Thermionic energy conversion to generate electric power at high operating temperatures to enable space missions requiring specific power sources to meet their power and propulsion needs is discussed. Thermionic energy conversion is one of several technologies vying to satisfy the requirements of future lunar and Martian exploration missions. The specific power for thermionic nuclear space power systems ranges from 10 W/kg at 10 kWe to about 100 W/kg at 2 MWe. Based on independent studies, it was determined that the U.S. would significantly benefit by making the thermionic reactor technology of the former Soviet Union available for future military, civil, and commercial space mission. The fiber-reinforced creep-resistant thermionic emitter electrode concept, as well as calculated lifetimes for emitter electrodes reinforced with fiber, and calculated temperature distributions near the thermionic fuel element fuel-lead region interface, are illustrated.

Ramalingam, Mysore L.; Young, Timothy J.

1993-09-01

102

Solar energy conversion with fluorescent collectors  

Microsoft Academic Search

A new principle for solar energy conversion is proposed and evaluated theoretically. Collection and concentration of direct\\u000a and diffuse radiation is possible by the use of a stack of transparent sheets of material doped with fluorescent dyes. High\\u000a efficiency of light collection can be achieved by light guiding and special design of collectors. The optical path length\\u000a in a triangular

A. Goetzberger; W. Greubel

1977-01-01

103

Solar thermochemical energy conversion and transport  

Microsoft Academic Search

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

J. H. McCrary; G. E. McCrary

1982-01-01

104

Thermoelectric energy conversion with solid electrolytes  

Microsoft Academic Search

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,

T. Cole

1983-01-01

105

System Performance Projections for TPV Energy Conversion  

SciTech Connect

TPV technology has advanced rapidly in the last five years, with diode conversion efficiency approaching >30%, and filter efficiency of {approx}80%. These achievements have enabled repeatable testing of 20% efficient small systems, demonstrating the potential of TPV energy conversion. Near term technology gains support a 25% efficient technology demonstration in the two year timeframe. However, testing of full size systems, which includes efficiency degradation mechanisms, such as: nonuniform diode illumination, diode and filter variability, temperature non-uniformities, conduction/convection losses, and lifetime reliability processes needs to be performed. A preliminary analysis of these differential effects has been completed, and indicates a near term integrated system efficiency of {approx}15% is possible using current technology, with long term growth to 18-20%. This report addresses the system performance issues.

PF Baldasaro; MW Dashiell; JE Oppenlander; JL Vell; P Fourspring; K Rahner; LR Danielson; S Burger; E Brown

2004-06-09

106

On mode conversion and wave reflection in magnetic Ap stars  

E-print Network

We investigate the effect of a strong large scale magnetic field on the reflection of high frequency acoustic modes in rapidly oscillating Ap stars. To that end we consider a toy model composed of an isothermal atmosphere matched onto a polytropic interior and determine the numerical solution to the set of ideal magneto-hydrodynamic equations in a local plane-parallel approximation with constant gravity. Using the numerical solution in combination with approximate analytical solutions that are valid in the limits where the magnetic and acoustic components are decoupled, we calculate the relative fraction of energy flux that is carried away in each oscillation cycle by running acoustic waves in the atmosphere and running magnetic waves in the interior. For oscillation frequencies above the acoustic cutoff we show that most energy losses associated with the presence of running waves occur in regions where the magnetic field is close to vertical. Moreover, by considering the depth dependence of the energy associ...

Sousa, S G

2008-01-01

107

On mode conversion and wave reflection in magnetic Ap stars  

E-print Network

We investigate the effect of a strong large scale magnetic field on the reflection of high frequency acoustic modes in rapidly oscillating Ap stars. To that end we consider a toy model composed of an isothermal atmosphere matched onto a polytropic interior and determine the numerical solution to the set of ideal magneto-hydrodynamic equations in a local plane-parallel approximation with constant gravity. Using the numerical solution in combination with approximate analytical solutions that are valid in the limits where the magnetic and acoustic components are decoupled, we calculate the relative fraction of energy flux that is carried away in each oscillation cycle by running acoustic waves in the atmosphere and running magnetic waves in the interior. For oscillation frequencies above the acoustic cutoff we show that most energy losses associated with the presence of running waves occur in regions where the magnetic field is close to vertical. Moreover, by considering the depth dependence of the energy associated with the magnetic component of the wave in the atmosphere we show that a fraction of the wave energy is kept in the oscillation every cycle. For frequencies above the acoustic cutoff frequency such energy is concentrated in regions where the magnetic field is significantly inclined in relation to the local vertical. Even though our calculations were aimed at studying oscillations with frequencies above the acoustic cutoff frequency, based on our results we discuss what results may be expected for oscillations of lower frequency.

S. G. Sousa; M. S. Cunha

2008-02-06

108

Ocean thermal energy conversion - materials issues  

SciTech Connect

The Ocean Thermal Energy Conversion (OTEC) Program, in the Ocean Energy Technology Division of the U.S. Department of Energy, is concerned with the development of options that can be utilized to extract and distribute significant amounts of energy from the ocean. The biofouling control and materials portion of the program is concerned with the development of effective and environmentally acceptable methods to minimize biofouling and corrosion in high thermal conductivity materials suitable for use in heat exchangers and condensers. The mechanical and chemical techniques employed for biofouling control are reviewed and the recent success with chlorination is presented. The corrosion of aluminum alloys, copper alloys, stainless steel, stainless alloys, and titanium in near-surface warm and deep cold water is reviewed with emphasis on aluminum alloys. The major materials issues are reviewed with emphasis on lifetime and cost.

Darby, J.B. Jr.

1984-01-01

109

Ocean Thermal Energy Conversion-materials issues  

SciTech Connect

The Ocean Thermal Energy Conversion (OTEC) Program, in the Ocean Energy Technology Division of the U.S. Department of Energy, is concerned with the development of options that can be utilized to extract and distribute significant amounts of energy from the ocean. The biofouling control and materials portion of the program is concerned with the development of effective and environmentally acceptable methods to minimize biofouling and corrosion in high thermal conductivity materials suitable for use in heat exchangers and condensers. The mechanical and chemical techniques employed for biofouling control is reviewed and the recent success with chlorination is presented. The corrosion of aluminum alloys, copper alloys, stainless steel, stainless alloys, and titanium in near-surface warm and deep cold water is examined with emphasis on aluminum alloys. The major materials issues are reviewed with emphasis on lifetime and cost.

Darby, J.B.

1984-09-01

110

Solar thermochemical energy conversion and transport  

NASA Astrophysics Data System (ADS)

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 and operated on the NMSU campus. A number of receiver elements (chemical reactors) have been tested in these laboratory facilities in an effort to optimize catalyst parameters and catalyst reactor configurations. These tests led to the design and fabrication of both low power and high power solar energy receivers which were operated successfully at the White Sands solar Furnace. Energy delivery methanation reactor design and parametric studies led to the fabrication and operation of laboratory closed-loop, energy conversion, transport, and delivery system. These latter experiments met with limited but promising success. Carbon deposition, though a problem, is believed to be controllable with the optimization of catalyst parameters and feedstock composition.

McCrary, J. H.; McCrary, G. E.

1982-11-01

111

Ocean energy conversion systems annual research report  

SciTech Connect

Alternative power cycle concepts to the closed-cycle Rankine are evaluated and those that show potential for delivering power in a cost-effective and environmentally acceptable fashion are explored. Concepts are classified according to the ocean energy resource: thermal, waves, currents, and salinity gradient. Research projects have been funded and reported in each of these areas. The lift of seawater entrained in a vertical steam flow can provide potential energy for a conventional hydraulic turbine conversion system. Quantification of the process and assessment of potential costs must be completed to support concept evaluation. Exploratory development is being completed in thermoelectricity and 2-phase nozzles for other thermal concepts. Wave energy concepts are being evaluated by analysis and model testing with present emphasis on pneumatic turbines and wave focussing. Likewise, several conversion approaches to ocean current energy are being evaluated. The use of salinity resources requires further research in membranes or the development of membraneless processes. Using the thermal resource in a Claude cycle process as a power converter is promising, and a program of R and D and subsystem development has been initiated to provide confirmation of the preliminary conclusion.

Not Available

1981-03-01

112

Energy transfer processes in solar energy conversion  

Microsoft Academic Search

We have made substantial progress in experimental and theoretical studies in two areas: Photoinduced donor to acceptor electron transfer followed by back transfer in random solutions; and electronic excitation transport in systems with complex inhomogeneous spatial geometries and inhomogeneous energy distributions. Through the development of accurate statistical mechanical theories, we have been able to relate dynamics in complex systems to

Fayer

1989-01-01

113

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

E-print Network

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.

E. Yu. Melkumova

2011-12-13

114

DIRECT CONVERSION OF NUCLEAR ENERGY INTO ELECTRICAL OR THRUST ENERGY  

Microsoft Academic Search

Direct conversion of nuclear energy into electrical energy or thrust ; involves the confinement of a plasma at temperatures of the order of 10⁸ ; deg K and higher, which excludes physical walls. Two concepts through which this ; may be done are introduced. In both cases spherical waves propagate radially ; inward. In the first, the amplitude is the

Fuechsel

1962-01-01

115

Photon-graviton conversion in a primordial magnetic field and the cosmic microwave background  

E-print Network

We reconsider the effects of photon-graviton conversion in a primordial magnetic field upon the cosmic microwave background radiation. We argue that plasma effects make the photon-graviton conversion process negligible.

Analia N. Cillis; Diego D. Harari

1996-09-30

116

Energy conversion systems design for fusion reactors  

SciTech Connect

Various energy conversion systems have been reviewed in order to select an efficient power cycle to be compatible with the fusion reactor requirements. The power cycles were selected for a toroidal confinement system with D-T and D-D fuel cycles and a tandem mirror reactor (TMR) with a D-/sup 3/He fuel cycle. Reversed Field Pinch Reactor (RFPR) was selected as an example of a toroidal confinement system with D-T fuel cycle since there has recently been a comprehensive design study for it. Tokamak was selected as an example of a toroidal confinement system with D-D fuel cycle. Tandem mirror reactor was chosen as an example of confinement for D-/sup 3/He fuel cycle. The steam cycle was found to be most suitable for the RFP and Tokamak reactors while a combination of direct energy conversion system and steam cycle was found to be most suitable for D-/sup 3/He tandem mirror reactor.

Dabiri, A.E.

1989-03-01

117

OCEAN THERMAL ENERGY CONVERSION PROGRAMMATIC ENVIRONMENTAL ASSESSMENT  

SciTech Connect

Significant achievements in Ocean Thermal Energy Conversion (OTEC) technology have increased the probability of producing OTEC-derived power in this decade with subsequent large-scale commercialization to follow by the turn of the century. Under U.S. Department of Energy funding, Interstate Electronics has prepared an OTEC Programmatic Environmental Assessment (EA) that considers tne development, demonstration, and commercialization of OTEC power systems. The EA considers several tecnnological designs (open cycle and closed cycle), plant configurations (land-based, moored, and plantship), and power usages (baseload electricity and production of ammonia and aluminum). Potencial environmental impacts, health and safety issues, and a status update of international, federal, and state plans and policies, as they may influence OTEC deployments, are included.

Sands, M.Dale

1980-08-01

118

Recycling of Wasted Energy: Thermal to Electrical Energy Conversion  

NASA Astrophysics Data System (ADS)

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.

Lim, Hyuck

119

Technology assessment of wind energy conversion systems  

SciTech Connect

Environmental data for wind energy conversion systems (WECSs) have been generated in support of the Technology Assessment of Solar Energy (TASE) program. Two candidates have been chosen to characterize the WECS that might be deployed if this technology makes a significant contribution to the national energy requirements. One WECS is a large machine of 1.5-MW-rated capacity that can be used by utilities. The other WECS is a small machine that is characteristic of units that might be used to meet residential or small business energy requirements. Energy storage systems are discussed for each machine to address the intermittent nature of wind power. Many types of WECSs are being studied and a brief review of the technology is included to give background for choosing horizontal axis designs for this study. Cost estimates have been made for both large and small systems as required for input to the Strategic Environmental Assessment Simulation (SEAS) computer program. Material requirements, based on current generation WECSs, are discussed and a general discussion of environmental impacts associated with WECS deployment is presented.

Meier, B. W.; Merson, T. J.

1980-09-01

120

Proceedings of the 33. intersociety energy conversion engineering conference  

Microsoft Academic Search

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,

Anghaie

1998-01-01

121

Elemental processes of transport and energy conversion in Earth's magnetosphere  

NASA Astrophysics Data System (ADS)

In the last 5 years observations from several missions and ground based observatories have honed in on the most elemental aspects of flux transport and energy conversion. Dipolarization fronts and their counterpart in the distant magnetotail "anti-dipolarization" fronts, which together are refered to herein as "reconnection fronts", usher the recently reconnected flux tubes from the near-Earth X-points and in the process convert magnetic energy to particle energy and wave radiation. On the tailward side they are responsible for plasmoid formation and acceleration. On the earthward side they result in elemental substorm current wedges or wedglets, which were initially postulated from ground observations alone. Recent observations have revealed how the interaction of wedgelets and the inner magnetosphere takes place. Questions remain with regards to the physics of the energy transfer process from global magnetic energy to local heating and waves, and with regards to the initiation of the X-point activations in space. Observations indicate that the latter may be induced by polar cap or dayside activity, suggesting a direct link between dayside reconnection and nightside phenomena. The likely causal sequence of events and open questions in light of these recent observations, and the field's outlook in anticipation of upcoming coordinated observations from the international Heliophysics System Observatory will be discussed.

Angelopoulos, Vassilis

122

Neural network theory based voltage and frequency controller for standalone wind energy conversion system  

Microsoft Academic Search

In this paper, a solid state voltage and frequency (VF) controller is proposed for a standalone wind energy conversion system (WECS) employing a permanent magnet synchronous generator (PMSG). The proposed VF controller consists of IGBTs (insulated gate bipolar transistors) based three-leg voltage source converter (VSC) with a battery energy storage system (BESS) at its dc link. The Adaline (adaptive linear

V. Sheeja; P. Jayaprakash; Bhim Singh; R. Uma

2010-01-01

123

Stretchable energy storage and conversion devices.  

PubMed

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

Yan, Chaoyi; Lee, Pooi See

2014-09-10

124

Quantum efficiency of photosynthetic energy conversion.  

PubMed Central

The quantum efficiency of photosynthetic energy conversion was investigated in isolated spinach chloroplasts by measurements of the quantum requirements of ATP formation by cyclic and noncyclic photophosphorylation catalyzed by ferredoxin. ATP formation had a requirement of about 2 quanta per 1 ATP at 715 nm (corresponding to a requirement of 1 quantum per electron) and a requirement of 4 quanta per ATP (corresponding to a requirement of 2 quanta per electron) at 554 nm. When cyclic and noncyclic photophosphorylation were operating concurrently at 554 nm, a total of about 12 quanta was required to generate the two NADPH and three ATP needed for the assimilation of one CO2 to the level of glucose. PMID:20627

Chain, R K; Arnon, D I

1977-01-01

125

Evidence of the theoretically predicted seismo-magnetic conversion  

NASA Astrophysics Data System (ADS)

Seismo-electromagnetic phenomena in porous media arise from seismic wave-induced fluid motion in the pore space, which perturbs the equilibrium of the electric double layer. This paper describes with details the original experimental apparatus built within the ultra-shielded chamber of the Low Noise Underground Laboratory of Rustrel (France). We measured seismo-magnetic conversions in moist sand using two induction magnetometers, and a pneumatic seismic source to generate the seismic wave propagation. We ensured to avoid the magnetometer vibrations, which could induce strong disturbances from induction origin. Interpretation of the data is improved by an analytical description of phase velocities for fast (Pf) and slow (Ps) longitudinal modes, transverse mode (S) as well as the extensional mode due to the cylindrical geometry of the sample. The purpose of this paper is to provide elements to measure correctly coseismic seismomagnetic fields and to specify their amplitude. The seismic arrivals recorded in the sample showing a 1200-1300ms-1 velocity have been associated to P and extensional waves. The measured seismo-magnetic arrivals show a velocity of about 800ms-1 close to the calculated phase velocity of S waves. Therefore, we show that the seismo-magnetic field is associated to the transverse part of the propagation, as theoretically predicted by Pride (1994), but never measured up to now. Moreover, the combined experimental and analytical approaches lead us to the conclusion that the measured seismo-magnetic field is probably about 0.035nT for a 1ms-2 seismic source acceleration (0.1g).

Bordes, Clarisse; Jouniaux, Laurence; Garambois, Stéphane; Dietrich, Michel; Pozzi, Jean-Pierre; Gaffet, Stéphane

2008-08-01

126

Power conversion from environmentally scavenged energy sources.  

SciTech Connect

As the power requirements for modern electronics continue to decrease, many devices which were once dependent on wired power are now being implemented as portable devices operating from self-contained power sources. The most prominent source of portable power is the electrochemical battery, which converts chemical energy into electricity. However, long lasting batteries require large amounts of space for chemical storage, and inevitably require replacement when the chemical reaction no longer takes place. There are many transducers and scavenging energy sources (SES) that are able to exploit their environment to generate low levels of electrical power over a long-term time period, including photovoltaic cells, thermoelectric generators, thermionic generators, and kinetic/piezoelectric power generators. This generated power is sustainable as long as specific environmental conditions exist and also does not require the large volume of a long lifetime battery. In addition to the required voltage generation, stable power conversion requires excess energy to be efficiently stored in an ultracapacitor or similar device and monitoring control algorithms to be implemented, while computer modeling and simulation can be used to complement experimental testing. However, building an efficient and stable power source scavenged from a varying input source is challenging.

Druxman, Lee Daniel

2007-09-01

127

Ocean Thermal Energy Conversion: Potential Environmental Impacts and Fisheries  

E-print Network

Ocean Thermal Energy Conversion: Potential Environmental Impacts and Fisheries Christina M Comfort Institute #12;Ocean Thermal Energy Conversion (OTEC) · Renewable energy ­ ocean thermal gradient · Large shock · Plume ­ Changes in local conditions ­ Aquaculture? ­ FAD effects + enhanced productivity? #12

Hawai'i at Manoa, University of

128

Energy conversion for megawatt space power systems  

NASA Technical Reports Server (NTRS)

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.

Ewell, R.

1983-01-01

129

Status of thermoelectronic laser energy conversion, TELEC  

NASA Technical Reports Server (NTRS)

A concept known as a thermo-electronic laser energy converter (TELEC), was studied as a method of converting a 10.6 micron CO2 laser beam into electric power. The calculated characteristics of a TELEC seem to be well matched to the requirements of a spacecraft laser energy conversion system. The TELEC is a high power density plasma device which absorbs an intense laser beam by inverse bremsstrahlung with the plasma electrons. In the TELEC process, electromagnetic radiation is absorbed directly in the plasma electrons producing a high electron temperature. The energetic electrons diffuse out of the plasma striking two electrodes which are in contact with the plasma at the boundaries. These two electrodes have different areas: the larger one is designated as the collector, the smaller one is designated as the emitter. The smaller electrode functions as an electron emitter provide continuity of the current. Waste heat is rejected from the collector electrode. An experiment was carried out with a high power laser using a cesium vapor TELEC cell with 30 cm active length. Laser supported plasma were produced in the TELEC device during a number of laser runs over a period of several days. Electric power from the TELEC was observed with currents in the range of several amperes and output potentials of less than 1 volt.

Britt, E. J.

1982-01-01

130

Nanomaterials for energy conversion and storage.  

PubMed

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

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

2013-04-01

131

Net energy analysis of small wind energy conversion systems  

NASA Astrophysics Data System (ADS)

The net energy of a small wind electric conversion system is calculated and compared with the net energy of other electricity sources. Net energy is the amount of energy remaining for consumer use after deducting the energy required to find and upgrade the energy source and construct and maintain the electricity generating system. A 3 kW rated wind electric system for residential use is examined. The amount of energy obtained from this system is estimated by using a computer-operated simulation model which incorporates wind speeds, residential electricity demands and parameters from the generator, inverter and storage components. The net energy gain for this wind system is better than that of other systems with which it is compared.

Haack, B. N.

1981-11-01

132

Science of Nanofluidics and Energy Conversion  

NASA Astrophysics Data System (ADS)

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

Xu, Baoxing

133

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)

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.

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

1976-01-01

134

Chalmers University of Technology Henrik Thunman Department of Energy Conversion  

E-print Network

in a volume depends on the flow in and out of the volume #12;Chalmers University of Technology Henrik ThunmanChalmers University of Technology Henrik Thunman Department of Energy Conversion ModellingSpecies #12;Chalmers University of Technology Henrik Thunman Department of Energy Conversion Continuity

135

Some preliminary considerations on photovoltaic conversion of solar energy  

Microsoft Academic Search

Tentative calculations on the feasibility, cost effectiveness, and overall reliability of solar energy via photovoltaic conversion are carried out. It is estimated that the cost of solar energy conversion will have to be cut by factors of 100 to 200 for it to become competitive with other sources of large-scale power in the foreseeable future. The importance of exploitation of

A. Egidi; G. V. Pallottino

1976-01-01

136

E2I EPRI Assessment Offshore Wave Energy Conversion Devices  

E-print Network

, government/industry, public/private collaborative program to assess and demonstrate the feasibilityE2I 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

137

Improving efficiency of thermoelectric energy conversion devices is a major  

E-print Network

q Ec1 Ec1 Ec2 e- e-e- e- e- e- e- Phonons Phonons Si SiGe Nanoscale Effects · Decrease in deviceAbstract · Improving efficiency of thermoelectric energy conversion devices is a major challenge to the bulk. · Size quantization effects found to dominate performance of nanoscale energy conversion devices

Walker, D. Greg

138

Wind Energy Conversion Using a Self-Excited Induction Generator  

Microsoft Academic Search

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

G. Raina; O. P. Malik

1983-01-01

139

Experimental demonstration of thermoacoustic energy conversion in a resonator  

Microsoft Academic Search

Using thermoacoustic energy conversions, both amplification and damping of acoustic intensity are demonstrated. A differentially heated regenerator is installed near the velocity node of the resonator and thereby a high specific acoustic impedance and a traveling wave phase are obtained. It is shown that the gain of acoustic intensity resulting from the traveling wave energy conversion reaches 1.7 in a

Tetsushi Biwa; Yusuke Tashiro; Uichiro Mizutani; Motoki Kozuka; Taichi Yazaki

2004-01-01

140

Acoustic to Electric Energy Conversion Using Piezoelectric Transducers  

Microsoft Academic Search

Presented is an analysis of a piezoelectric transduction system and a comparison to experimental data. A mathematical model is used to compare the external electric effects of an electric energy conversion system using piezoelectric ceramic transducers. The energy conversion is from electric to mechanical and back to electric. The transduction system is modeled by an electromechanical circuit in which electrical

Joel Marcus Hall

1993-01-01

141

Photoacoustic energy conversion efficiency for a simplified absorber model  

Microsoft Academic Search

Electromagnetic energy that is carried by light is converted to thermodynamic and mechanical forms of energy, i.e., heat and kinetic energy, when light interacts with tissue. The conversion efficiency from the absorbed radiative energy by an object into the kinetic energy is an important issue in the study of laser-tissue interactions, because the kinetic energy is the source of acoustic

Pingyu Liu

1994-01-01

142

Performance of Tornado Wind Energy Conversion Systems  

SciTech Connect

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.

Volk, T.

1982-09-01

143

Theoretical investigation of solar energy conversion and water oxidation catalysis  

E-print Network

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 ...

Wang, Lee-Ping

2011-01-01

144

Thermoelectric, thermionic and thermophotovoltaic energy conversion Ali Shakouri  

E-print Network

Thermoelectric, thermionic and thermophotovoltaic energy conversion Ali Shakouri Jack Baskin School of thermoelectric, ballistic thermionic and quasi diffusive thermionic energy converters are compared. First thermoelectric power factor. For this to occur, the electron transverse momentum perpendicular to heterostructure

145

Energy Conversion in Photosynthesis: A Paradigm for Solar Fuel Production  

NASA Astrophysics Data System (ADS)

Solar energy has the capacity to fulfill global human energy demands in an environmentally and socially responsible manner, provided efficient, low-cost systems can be developed for its capture, conversion, and storage. Toward these ends, a molecular-based understanding of the fundamental principles and mechanistic details of energy conversion in photosynthesis is indispensable. This review addresses aspects of photosynthesis that may prove auspicious to emerging technologies. Conversely, areas in which human ingenuity may offer innovative solutions, resulting in enhanced energy storage efficiencies in artificial photosynthetic constructs, are considered. Emphasis is placed on photoelectrochemical systems that utilize water as a source of electrons for the production of solar fuels.

Moore, Gary F.; Brudvig, Gary W.

2011-03-01

146

Solar energy conversion and storage systems for the future  

Microsoft Academic Search

The possible utilization of solar energy in its various manifestations such as heat, winds, tides, and ocean thermal gradients is reviewed. Methods of solar energy collection, conversion, and utilization are examined, along with the solar energy potential. Special attention is given to various systems for meeting the needs of solar energy storage. The systems considered include: (1) thermal energy storage

R. Ramakumar; H. J. Allison; W. L. Hughes

1974-01-01

147

Open cycle ocean thermal energy conversion system  

DOEpatents

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 warm ocean water exits the evaporator through a second prestressed concrete skirt-conduit structure located circumferentially about and radially within the first skirt-conduit structure. The radially inner surface of the second skirt conduit structure constitutes a cylinder which functions as the turbine's outer casing and obviates the need for a conventional outer housing. The turbine includes a radially enlarged disc element attached to the shaft for supporting at least one axial row of radially directed blades through which the steam is expanded. A prestressed concrete inner casing structure of the turbine has upstream and downstream portions respectively situated upstream and downstream from the disc element. The radially outer surfaces of the inner casing portions and radially outer periphery of the axially interposed disc cooperatively form a downwardly radially inwardly tapered surface. An annular steam flowpath of increasing flow area in the downward axial direction is radially bounded by the inner and outer prestressed concrete casing structures. The inner casing portions each include a transversely situated prestressed concrete circular wall for rotatably supporting the turbine shaft and associated structure. The turbine blades are substantially radially coextensive with the steam flowpath and receive steam from the evaporator through an annular array of prestressed concrete stationary vanes which extend between the inner and outer casings to provide structural support therefor and impart a desired flow direction to the steam.

Wittig, J. Michael (West Goshen, PA)

1980-01-01

148

Energy conversion at the Earth's magnetopause using single and multispacecraft methods  

NASA Astrophysics Data System (ADS)

We present a small statistical data set, where we investigate energy conversion at the magnetopause using Cluster measurements of magnetopause crossings. The Cluster observations of magnetic field, plasma velocity, current density and magnetopause orientation are needed to infer the energy conversion at the magnetopause. These parameters can be inferred either from accurate multispacecraft methods, or by using single-spacecraft methods. Our final aim is a large statistical study, for which only single-spacecraft methods can be applied. The Cluster mission provides an opportunity to examine and validate single-spacecraft methods against the multispacecraft methods. For single-spacecraft methods, we use the Generic Residue Analysis (GRA) and a standard one-dimensional current density method using magnetic field measurements. For multispacecraft methods, we use triangulation (Constant Velocity Approach - CVA) and the curlometer technique. We find that in some cases the single-spacecraft methods yield a different sign for the energy conversion than compared to the multispacecraft methods. These sign ambiguities arise from the orientation of the magnetopause, choosing the interval to be analyzed, large normal current and time offset of the current density inferred from the two methods. By using the Finnish Meteorological Institute global MHD simulation GUMICS-4, we are able to determine which sign is likely to be correct, introducing an opportunity to correct the ambiguous energy conversion values. After correcting the few ambiguous cases, we find that the energy conversion estimated from single-spacecraft methods is generally lower by 70% compared to the multispacecraft methods.

Anekallu, C. R.; Palmroth, M.; Pulkkinen, T. I.; Haaland, S. E.; Lucek, E.; Dandouras, I.

2011-11-01

149

Tandem filters using frequency selective surfaces for enhanced conversion efficiency in a thermophotovoltaic energy conversion system  

DOEpatents

This invention relates to the field of thermophotovoltaic (TPV) direct energy conversion. In particular, TPV systems use filters to minimize parasitic absorption of below bandgap energy. This invention constitutes a novel combination of front surface filters to increase TPV conversion efficiency by reflecting useless below bandgap energy while transmitting a very high percentage of the useful above bandgap energy. In particular, a frequency selective surface is used in combination with an interference filter. The frequency selective surface provides high transmission of above bandgap energy and high reflection of long wavelength below bandgap energy. The interference filter maintains high transmission of above bandgap energy and provides high reflection of short wavelength below bandgap energy and a sharp transition from high transmission to high reflection.

Dziendziel, Randolph J. (Middle Grove, NY); DePoy, David Moore (Clifton Park, NY); Baldasaro, Paul Francis (Clifton Park, NY)

2007-01-23

150

Tandem filters using frequency selective surfaces for enhanced conversion efficiency in a thermophotovoltaic energy conversion system  

DOEpatents

This invention relates to the field of thermophotovoltaic (TPV) direct energy conversion. In particular, TPV systems use filters to minimize parasitic absorption of below bandgap energy. This invention constitutes a novel combination of front surface filters to increase TPV conversion efficiency by reflecting useless below bandgap energy while transmitting a very high percentage of the useful above bandgap energy. In particular, a frequency selective surface is used in combination with an interference filter. The frequency selective surface provides high transmission of above bandgap energy and high reflection of long wavelength below bandgap energy. The interference filter maintains high transmission of above bandgap energy and provides high reflection of short wavelength below bandgap energy and a sharp transition from high transmission to high reflection.

Dziendziel, Randolph J. (Middle Grove, NY); Baldasaro, Paul F. (Clifton Park, NY); DePoy, David M. (Clifton Park, NY)

2010-09-07

151

Potassium plasma cell facilitates thermionic energy conversion process  

NASA Technical Reports Server (NTRS)

Thermionic energy converter converts nuclear generated heat directly into high frequency and direct current output. It consists of a potassium plasma cell, a tantalum emitter, and a silver plated copper collector. This conversion process eliminates the steam interface usually required between the atomic heat source and the electrical conversion system.

Richards, H. K.

1967-01-01

152

Semiconductor nanowires for photovoltaic and photoelectrochemical energy conversion  

NASA Astrophysics Data System (ADS)

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.

Dasgupta, Neil P.; Yang, Peidong

2014-06-01

153

Semiconductor nanowires for photovoltaic and photoelectrochemical energy conversion  

SciTech Connect

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.

Dasgupta, Neil; Yang, Peidong

2013-01-23

154

Maximum Power Point Tracking for Ocean Wave Energy Conversion  

Microsoft Academic Search

Many forms of renewable energy exist in the world's oceans, with ocean wave energy showing great potential. However, the ocean environment presents many challenges for cost-effective renewable energy conversion, including optimal control of a wave energy converter (WEC). This paper presents a maximum power point tracking (MPPT) algorithm for control of a point absorber WEC. The algorithm and testing hardware

Ean A. Amon; Ted K. A. Brekken; Alphonse A. Schacher

2012-01-01

155

Energy production from biomass (part 2): conversion technologies  

Microsoft Academic Search

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,

Peter McKendry

2002-01-01

156

Planar high energy permanent magnets  

Microsoft Academic Search

Samarium-cobalt permanent magnets were fabricated by arc plasma spraying in order to evaluate this technique as an economical method for fabricating cobalt-rare earth magnets for advanced traveling wave tubes and crossfield amplifiers. Bar magnets were produced having a coercive force of 6100 oersteds and an energy product of 10.8 million gauss-oersted. The magnetic properties in bar magnets were significantly better

M. C. Willson; R. J. Janowiecki

1975-01-01

157

Soft materials for linear electromechanical energy conversion  

E-print Network

We briefly review the literature of linear electromechanical effects of soft materials, especially in synthetic and biological polymers and liquid crystals (LCs). First we describe results on direct and converse piezoelectricity, and then we discuss a linear coupling between bending and electric polarization, which maybe called bending piezoelectricity, or flexoelectricity.

Antal Jakli; Nandor Eber

2014-07-29

158

Semiconductor Nanowires and Nanotubes for Energy Conversion  

NASA Astrophysics Data System (ADS)

In recent years semiconductor nanowires and nanotubes have garnered increased attention for their unique properties. With their nanoscale dimensions comes high surface area and quantum confinement, promising enhancements in a wide range of applications. 1-dimensional nanostructures are especially attractive for energy conversion applications where photons, phonons, and electrons come into play. Since the bohr exciton radius and phonon and electron mean free paths are on the same length scales as nanowire diameters, optical, thermal, and electrical properties can be tuned by simple nanowire size adjustments. In addition, the high surface area inherent to nanowires and nanotubes lends them towards efficient charge separation and superior catalytic performance. In thermoelectric power generation, the nanoscale wire diameter can effectively scatter phonons, promoting reductions in thermal conductivity and enhancements in the thermoelectric figure of merit. To that end, single-crystalline arrays of PbS, PbSe, and PbTe nanowires have been synthesized by a chemical vapor transport approach. The electrical and thermal transport properties of the nanowires were characterized to investigate their potential as thermoelectric materials. Compared to bulk, the lead chalcogenide nanowires exhibit reduced thermal conductivity below 100 K by up to 3 orders of magnitude, suggesting that they may be promising thermoelectric materials. Smaller diameters and increased surface roughness are expected to give additional enhancements. The solution-phase synthesis of PbSe nanowires via oriented attachment of nanoparticles enables facile surface engineering and diameter control. Branched PbSe nanowires synthesized by this approach showed near degenerately doped charge carrier concentrations. Compared to the bulk, the PbSe nanowires exhibited a similar Seebeck coefficient and a significant reduction in thermal conductivity in the temperature range 20 K to 300 K. Thermal annealing of the PbSe nanowires allowed their thermoelectric properties to be controllably tuned by increasing their carrier concentration or hole mobility. After optimal annealing, single PbSe nanowires exhibited a thermoelectric figure of merit (ZT) of 0.12 at 300 K. In addition, using a field-effect gated device, the Seebeck coefficient of single PbSe nanowires could be tuned from 64 to 193 muV?K-1. This direct electrical field control of the electrical conductivity and Seebeck coefficient suggests a powerful strategy for optimizing ZT in thermoelectric devices and these results represent the first demonstration of field-effect modulation of the thermoelectric figure of merit in a single semiconductor nanowire. This novel strategy for thermoelectric property modulation could prove especially important in optimizing the thermoelectric properties of semiconductors where reproducible doping is difficult to achieve. Recent theoretical work has shown large enhancements in ZT for single-crystal nanowires containing nanoscale interfaces along their lengths. M2O3(ZnO) n ( M = In, Ga, Fe) superlattice nanowires were synthesized via a novel solid-state diffusion approach to investigate this possible enhancement. Using atomic resolution Z-contrast STEM imaging a detailed structural analysis was performed on In2-xGaxO3(ZnO) n nanowires, leading to the discovery that octahedral inclusions within the superlattice structure are likely generated through a defect-assisted process. Single-nanowire thermal and electrical measurements on In2-x GaxO3(ZnO)n reveal a simultaneous improvement in all contributing factors to the thermoelectric figure of merit, giving an order of magnitude enhancement over similar bulk materials at room temperature. This is the first report of enhancement of all three thermoelectric parameters (Seebeck coefficient, electrical conductivity, and thermal resistivity) for a nanowire system. Photoelectrochemical water splitting is another exciting renewable energy application that can benefit from the high surface area of nanomaterials. Recently, (Ga1-xZnx)(N1-xOx) has gained

Fardy, Melissa Anne

159

NONLINEAR CIRCUITS AND ANTENNAS FOR MICROWAVE ENERGY CONVERSION  

E-print Network

and Computer Engineering by Zoya Popovic Regan Zane Date The nal copy of this thesis has been examined) Nonlinear Circuits and Antennas for Microwave Energy Conversion Thesis directed by Professor Zoya Popovic

Popovic, Zoya

160

Experimental demonstration of thermoacoustic energy conversion in a resonator.  

PubMed

Using thermoacoustic energy conversions, both amplification and damping of acoustic intensity are demonstrated. A differentially heated regenerator is installed near the velocity node of the resonator and thereby a high specific acoustic impedance and a traveling wave phase are obtained. It is shown that the gain of acoustic intensity resulting from the traveling wave energy conversion reaches 1.7 in a positive temperature gradient and 0.3 in a negative gradient. When the regenerator is replaced with a stack, it is found that the gain reaches 2.3, exceeding the temperature ratio (=1.9) of both ends of the stack. This is brought about by the addition of standing wave energy conversion. The present results would contribute to the development of new acoustic devices using thermoacoustic energy conversion. PMID:15244723

Biwa, Tetsushi; Tashiro, Yusuke; Mizutani, Uichiro; Kozuka, Motoki; Yazaki, Taichi

2004-06-01

161

Space electric power design study. [laser energy conversion  

NASA Technical Reports Server (NTRS)

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.

Martini, W. R.

1976-01-01

162

Compact harsh environment energy conversion systems  

E-print Network

effect on the optimal design of submersible PM (permanent magnet) machines, and a design procedure to account for this loss component in the design was developed. The application of a dual winding exterior rotor PM machine in a downhole environment...

Ahmed, Shehab

2009-05-15

163

Solar energy conversion arrangement utilizing photovoltaic members  

Microsoft Academic Search

An arrangement for converting solar energy directly to electrical energy is disclosed herein and utilizes a group of photovoltaic-like panel members, each of which is designed to convert solar energy into electrical energy by developing a voltage across opposite terminals thereof in response to and dependent upon its collection of solar energy. These panel members are electrically interconnected together in

1983-01-01

164

Conversion of laser energy to gas kinetic energy  

NASA Technical Reports Server (NTRS)

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.

Caledonia, G. E.

1975-01-01

165

Alternative energy conversion demonstration laboratory at U. S. Naval Academy  

SciTech Connect

This paper describes an alternative energy conversion demonstration laboratory which supplements classroom theory in a senior engineering elective course in energy conversion in the Department of Mechanical Engineering at the U.S. Naval Academy. Oil, nuclear energy, and other conventional sources of power have been the dominant sources for industrial society and the U.S. Navy, and will continue to be so for the foreseeable future. There are other possibilities, however, including wind power, solar power, ocean thermal power and tidal power. A need for alternative sources of energy for the Navy was recognized at the time of the Arab oil embargo in 1973, and an academic program in alternative energy has been developed to help satisfy that need. Specific demonstrations included in this paper are as follows: Mechanical modeling of the depletion of energy reserve, Computer graphic simulation of energy consumption and energy resource exhaust, Wind model, Thermax helius rotor wind machine, Solar breeze - an electric sailboat project, Vertical axis wind turbine, Helicopter, airplane propeller and windmill models test in wind tunnel, Ocean Thermal Energy Conversion Device Demonstration, Pneumatic Wave Energy Conversion Device Demonstration, Chemical Energy Storage Device Demonstration, Solar Energy Demonstration.

Wu, C.

1983-12-01

166

Waterborne noise due to ocean thermal energy conversion plants  

Microsoft Academic Search

Public law reflects a United States national commitment to the rapid development of Ocean Thermal Energy Conversion (OTEC) as an alternate energy source. OTEC plants extract the stored solar energy from the world's tropical seas and in so doing pose a potential for altering the character of the ambient noise there. The sources of noise from an OTEC plant are

Claus P. Janota; D. E. Thompson

1983-01-01

167

Counter-rotating wave energy conversion turbine  

SciTech Connect

A counter-rotating turbine for converting energy from waves. A turbine is positioned in a pneumatic-type wave energy converter and converts the energy of alternating air flow above the internal water surface into mechanical energy. The turbine has counter-rotating runners and guide vanes located both upstream and downstream, and the alternating air flow in the energy converter excites the turbine runners after being turned by the guide vanes.

McCormick, M.E.

1981-06-09

168

Proceedings of the 25th intersociety energy conversion engineering conference  

Microsoft Academic Search

This book contains the proceedings of the 25th intersociety energy conversion engineering conference, Volume 4. Topics covered include: Thermal management, Transportation, Advanced sulfur control strategies for coal, Needs and (some) solutions for integrated environmental controls, Systems solutions for energy\\/environmental conflicts, Control systems, motor\\/generators and flywheels in energy storage, Advanced phase change media for thermal energy storage, Thermal energy storage systems

P. A. Nelson; W. W. Schertz; R. H. Till

1990-01-01

169

Direct Energy Conversion for Fast Reactors  

NASA Astrophysics Data System (ADS)

Thermoelectric generators (TEG) are a well-established technology for compact low power output long-life applications. Solid state TEGs are the technology of choice for many space missions and remote earth-based applications. Use of solid state TEGs in these applications requires engineering designs that minimize the weight and volume of the device. Thermal to electric conversion efficiency, while an important design consideration, is not the principal design factor. However, design of a TEG for a fast reactor nuclear power plant requires higher thermal efficiencies in order to achieve competitive power generation costs.

Brown, N. W.; Vogt, D.; Cooper, J.; Chapline, G.; Turchi, P.

2000-07-01

170

Energy Conversion and Storage Program: 1992 Annual report  

SciTech Connect

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.

Cairns, E.J.

1993-06-01

171

2007 Survey of Energy Resources World Energy Council 2007 Ocean Thermal Energy Conversion COUNTRY NOTES  

E-print Network

a greater interest in other alternative energy sources. Barbados With the high petroleum product prices2007 Survey of Energy Resources World Energy Council 2007 Ocean Thermal Energy Conversion 573 COUNTRY NOTES The Country Notes on OTEC compiled for previous editions of the Survey of Energy Resources

172

Redox flow cells for energy conversion  

Microsoft Academic Search

Energy storage technologies provide an alternative solution to the problem of balancing power generation and power consumption. Redox flow cells are designed to convert and store electrical energy into chemical energy and release it in a controlled fashion when required. Many redox couples and cell designs have being evaluated. In this paper, redox flow systems are compared in the light

C. Ponce de León; A. Frías-Ferrer; J. González-García; D. A. Szánto; F. C. Walsh

2006-01-01

173

Western Energy Company advanced coal conversion process  

Microsoft Academic Search

Since 1968, Western Energy has been investigated methods of upgrading low ranked coals to reduce shipping costs and mitigate safety hazards associated with storage of such coals. In the early 1980's and MSE process engineer, consulting for Western Energy developed the basic ACCP concept. Western Energy developed and patented the process and is currently engaged in its commercialization with Northern

R. W. Sheldon; D. L. Rosholt; S. T. Kujawa

1991-01-01

174

Conversion of acoustic energy by lossless liners  

Microsoft Academic Search

The Blokhintzev acoustic energy equation is applied to a two-dimensional duct containing a uniform flow with a finite length lining. It is shown that the difference of the incident and outgoing acoustic energy differs in general from the energy dissipated in the liner, the difference being related to the displacements at the liner's edges. It is shown that in the

W. Moehring; W. Eversman

1982-01-01

175

Pin stack array for thermoacoustic energy conversion  

DOEpatents

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.

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

1995-01-01

176

Revisit ocean thermal energy conversion system  

Microsoft Academic Search

The earth, covered more than70.8% by the ocean, receives most of itsenergy from the sun. Solar energy istransmitted through the atmosphere andefficiently collected and stored in thesurface layer of the ocean, largely in thetropical zone. Some of the energy isre-emitted to the atmosphere to drive thehydrologic cycle and wind. The wind fieldreturns some of the energy to the ocean inthe

JOSEPH C. HUANG; HANS J. KROCK; STEPHEN K. ONEY

2003-01-01

177

Wind energy conversion systems using fuzzy sliding mode control  

Microsoft Academic Search

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

Qi Chen; LiangHai Chen; LinGao Wang

2011-01-01

178

Nanostructured materials for advanced energy conversion and storage devices  

Microsoft Academic Search

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

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

2005-01-01

179

Vibrational energy redistribution in glyoxal following internal conversion  

E-print Network

pumped excitation/ detection vacuum chamber is attached. Inside the cross is the beam source, whichVibrational energy redistribution in glyoxal following internal conversion R. Naaman,a) D. M 4 June 1979; accepted 10 August 1979) The vibrational redistribution of energy following internal

Zare, Richard N.

180

Thermo chemical conversion of biomass – Eco friendly energy routes  

Microsoft Academic Search

Biomass is indirect source of solar energy and it is renewable in nature. It is one of the most important energy source in near future because of its extensive spread availability and promising potential to reduce global warming. Thermo chemical conversion of biomass yield variety of solid, liquid and gaseous fuels and have equal importance both at industrial and ecological

N. L. Panwar; Richa Kothari; V. V. Tyagi

2012-01-01

181

Wind Energy Conversion Systems. A Unit of Instruction.  

ERIC Educational Resources Information Center

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…

Greenwald, Martin

182

Sun-tracking solar energy conversion system  

Microsoft Academic Search

A number of solar energy converter assemblies are carried by a support frame which is mounted for independent rotation about a horizontal and a vertical axis. Sensors detect the position of the sun; and control circuitry positions the support frame in elevation and azimuth so that the converter assemblies track and face the sun whenever the sun incident energy is

1980-01-01

183

Ris Energy Report 2 Bioenergy conversion  

E-print Network

- modynamic process or the combustion heat is trans- ferred to a secondary working fluid. In the direct cycle to generate heat, electricity and pro- cess steam. During the last twenty years combustion technologies like energy from biomass but, ultimately, the energy originates from combustion. Be it either the direct

184

Energy Conversion and Storage Program. 1990 annual report  

SciTech Connect

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 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. Topics include identification of new electrochemical couples for advanced rechargeable batteries, improvements in battery and fuel-cell materials, and the establishment of engineering principles applicable to electrochemical energy storage and conversion. 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 waste streams from synfuel plants and coal gasifiers. Other research projects seek to identify and characterize the constituents of liquid fuel-system streams and to devise energy-efficient means for their separation. Materials Applications research includes the evaluation of the properties of advanced materials, as well as the development of novel preparation techniques. For example, the use of advanced techniques, such as sputtering and laser ablation, are being used to produce high-temperature superconducting films.

Cairns, E.J.

1992-03-01

185

Primary Photosynthetic Energy Conversion in Bacterial Reaction Centers  

NASA Astrophysics Data System (ADS)

The development of human societies is strongly influenced by the available energetic resources. In a period where the limitations of conventional fossil energy carriers become as evident as the often uncontrollable dangers of nuclear energy, one has to reconsider regenerative energy resources. Here photovoltaic or photochemical use of solar energy is an important approach. Since the early days of evolution some two billion years ago, the dominant energetic input into the life system on earth occurs via the conversion of solar energy performed in photosynthetic organisms. The fossil energy carriers that we use and waste today have been produced by photosynthesis over millions of years. In the race for an extended and versatile use of solar energy, semiconductorbased photovoltaic devices have been developed. However, even after decades of intense engineering they cannot serve as a competitive alternative to fossil energy. Under these circumstances new alternatives are required. One line of scientific development may use the operational principles of photosynthesis since photosynthesis is still our main energy source. In this respect, we will present results on the basic concepts of energy conversion in photosynthetic bacteria, which could be used as a guideline to alternative light energy conversion systems.

Zinth, Wolfgang; Wachtveitl, J.

186

Layout design optimization for magneto-electro-elastic laminate composites for maximized energy conversion under mechanical loading  

NASA Astrophysics Data System (ADS)

Magneto-electro-elastic (MEE) laminate composites with piezoelectric and piezomagnetic phases can be utilized as materials providing energy conversion among magnetic, electric and mechanical energies. This work is concerned with the development of a systematic design method of MEE composites with maximized conversion of mechanical energy to electric and/or magnetic energy. To predict the energy conversion phenomena, a fully coupled MEE theory is employed. A composite plate is assumed to be simply supported and is discretized into a number of laminates for analysis using a semi-analytic finite element method. Since the optimal stacking sequences for piezoelectric/piezomagnetic phases and the optimal thickness for each phase must be simultaneously determined, we propose formulating the design problem as a topology optimization problem. To implement the topology optimization, two interpolation models, the standard SIMP (solid isotropic material with penalization) model and the micromechanics model, are investigated. After solving benchmark test problems, design examples dealing with multifunctional composites are considered.

Sun, Kyung Ho; Kim, Yoon Young

2010-05-01

187

Polymer Based Nanocomposites for Solar Energy Conversion  

SciTech Connect

Organic semiconductor-based photovoltaic devices offer the promise of low cost photovoltaic technology that can be manufactured via large-scale, roll-to-roll printing techniques. Existing organic photovoltaic devices are currently limited to solar power conversion efficiencies of 3?5%. This is because of poor overlap between the absorption spectrum of the organic chromophores and the solar spectrum, non-ideal band alignment between the donor and acceptor species, and low charge carrier mobilities. To address these issues, we are investigating the development of dendrimeric organic semiconductors that are readily synthesized with high purity. They also benefit from optoelectronic properties, such as band gap and band positions, which can be easily tuned by substituting different chemical groups into the molecule. Additionally, we are developing nanostructured oxide/conjugated polymer composite photovoltaics. These composites take advantage of the high electron mobilities attainable in oxide semiconductors and can be fabricated using low-temperature solution-based growth techniques. Here, we discuss the synthesis and preliminary device results of these novel materials and composites.

Shaheen, S.; Olson, D.; White, M.; Mitchell, W.; Miedaner, A.; Curtis, C.; Rumbles, G.; Gregg, B.; Ginley, D.

2005-01-01

188

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

E-print Network

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

Nycander, Jonas

189

Thermal energy conversion systems overview for fusion reactors  

SciTech Connect

The author describes various thermal energy conversion systems reviewed in order to select an efficient power cycle that is compatible with fusion reactor requirements. The most suitable power cycles were selected for a toroidal confinement system with deuterium-tritium and deuterium-deuterium fuel cycles and for a tandem mirror reactor (TMR) with a D-/sup 3/He fuel cycle. The steam cycle was found to be most suitable for the reversed-field pinch and tokamak reactors, whereas a combination of a direct energy conversion system and a steam cycle was found to be most suitable for a D-/sup 3/He TMR. It is anticipated that the energy conversion systems of all fusion reactors fall under these two categories.

Dabiri, A.E. (Science Applications International Corp., San Diego, CA (US))

1989-09-01

190

French work on ocean thermal energy conversion  

NASA Astrophysics Data System (ADS)

The ocean is discussed as a world-wide potential source of renewable energy, with special attention given to the 'deposit' of ocean thermal energy, which is determined by the temperature difference existing between surface water and that at a depth of 1000 m. A brief history of work done in France is presented, and mention is made of the work of d'Arsonval (1881), Claude and Boucherot (1926), and of projects, such as those at Abidjan and Guadeloupe. Attention is given to the French ocean thermal energy sites, to the Empain-Schneider closed-cycle studies, and the open-cycle floating ocean thermal energy station, with a discussion of thermodynamic considerations and cold water pipes. Problems and prospects are reviewed.

Marchand, P.

191

Guidelines in Wave Energy Conversion System Design  

E-print Network

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...

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

2014-01-01

192

Wind energy conversion over Ligurian Apennines  

NASA Astrophysics Data System (ADS)

A detailed analysis of wind energy availability at Mount Capellino (Genoa, Italy), based on wind data for a twenty year period, shows that wind energy is a promising renewable natural energy source in this part of the Ligurian Apennines. The instantaneous power output of a real aerogenerator has been integrated over the time to determine the energy output per unit area swept by the rotor over a year and a month respectively. Using a realistic capacity of 0.4 kW/m2 for the ideal machine, the annual power density output is 645 kWh/m2 at 30 m above ground level. It is estimated that five medium size wind-powered generators of 20 m in rotor diameter can produce approximately 1 GWh per year.

Flocchini, G.; Pasquale, V.; Sciarrone, V.

1983-06-01

193

Vibration-to-electric energy conversion  

Microsoft Academic Search

A system is proposed to convert ambient mechanical vibration into electrical energy for use in powering autonomous low-power electronic systems. The energy is transduced through the use of a variable capacitor, which has been designed with MEMS (microelectromechanical systems) tech- nology. A low-power controller IC has been fabricated in a 0 6µm CMOS pro- cess and has been tested and

Scott Meninger; Jose Oscar Mur-Miranda; Rajeevan Amirtharajah; Anantha Chandrakasan; Jeffrey Lang

1999-01-01

194

Supramolecular Structures for Photochemical Energy Conversion  

SciTech Connect

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.

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

2003-08-26

195

Emerging electrochemical energy conversion and storage technologies  

PubMed Central

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

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

2014-01-01

196

Emerging electrochemical energy conversion and storage technologies.  

PubMed

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

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

2014-01-01

197

The plasmatron: Advanced mode thermionic energy conversion  

NASA Technical Reports Server (NTRS)

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.

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

1976-01-01

198

Porous media for catalytic renewable energy conversion  

NASA Astrophysics Data System (ADS)

A novel flow-based method is presented to place catalytic nanoparticles into a reactor by sol-gelation of a porous ceramic consisting of copper-based nanoparticles, silica sand, ceramic binder, and a gelation agent. This method allows for the placement of a liquid precursor containing the catalyst into the final reactor geometry without the need of impregnating or coating of a substrate with the catalytic material. The so generated foam-like porous ceramic shows properties highly appropriate for use as catalytic reactor material, e.g., reasonable pressure drop due to its porosity, high thermal and catalytic stability, and excellent catalytic behavior. The catalytic activity of micro-reactors containing this foam-like ceramic is tested in terms of their ability to convert alcoholic biofuel (e.g. methanol) to a hydrogen-rich gas mixture with low concentrations of carbon monoxide (up to 75% hydrogen content and less than 0.2% CO, for the case of methanol). This gas mixture is subsequently used in a low-temperature fuel cell, converting the hydrogen directly to electricity. A low concentration of CO is crucial to avoid poisoning of the fuel cell catalyst. Since conventional Polymer Electrolyte Membrane (PEM) fuel cells require CO concentrations far below 100 ppm and since most methods to reduce the mole fraction of CO (such as Preferential Oxidation or PROX) have CO conversions of up to 99%, the alcohol fuel reformer has to achieve initial CO mole fractions significantly below 1%. The catalyst and the porous ceramic reactor of the present study can successfully fulfill this requirement.

Hotz, Nico

2012-05-01

199

Nanogold plasmonic photocatalysis for organic synthesis and clean energy conversion.  

PubMed

This review provides the basic concepts, an overall survey and the state-of-the art of plasmon-based nanogold photocatalysis using visible light including fundamental understanding and major applications to organic reactions and clean energy-conversion systems. First, the basic concepts of localized surface plasmon resonance (LSPR) are recalled, then the major preparation methods of AuNP-based plasmonic photocatalysts are reviewed. The major part of the review is dedicated to the latest progress in the application of nanogold plasmonic photocatalysis to organic transformations and energy conversions, and the proposed mechanisms are discussed. In conclusion, new challenges and perspectives are proposed and analyzed. PMID:25017125

Wang, Changlong; Astruc, Didier

2014-10-21

200

An equation for thermionic currents in vacuum energy conversion diodes  

SciTech Connect

Apparent thermionic emission constants A{sup {asterisk}} are commonly reported with values deviating from the theoretical value of 120thinspA/cm{sup 2}thinspK{sup 2}. For thermionic energy conversion diodes, using A{sup {asterisk}} in the conventional equation for predicting net currents is found to violate basic physics laws and may result in poor predictive accuracy. A general equation for vacuum energy conversion diodes is proposed to prevent misuse of A{sup {asterisk}}. {copyright} {ital 1998 American Institute of Physics.}

Marshall, A.C. [U.S. Defense Special Weapons Agency--Special Projects Office, 1680 Texas Street, Kirtland Air Force Base, Albuquerque, New Mexico 87117-5669 (United States)] [U.S. Defense Special Weapons Agency--Special Projects Office, 1680 Texas Street, Kirtland Air Force Base, Albuquerque, New Mexico 87117-5669 (United States)

1998-11-01

201

Low to high temperature energy conversion system  

NASA Technical Reports Server (NTRS)

A method for converting heat energy from low temperature heat sources to higher temperature was developed. It consists of a decomposition chamber in which ammonia is decomposed into hydrogen and nitrogen by absorbing heat of decomposition from a low temperature energy source. A recombination reaction then takes place which increases the temperature of a fluid significantly. The system is of use for the efficient operation of compact or low capital investment turbine driven electrical generators, or in other applications, to enable chemical reactions that have a critical lower temperature to be used. The system also recovers heat energy from low temperature heat sources, such as solar collectors or geothermal sources, and converts it to high temperatures.

Miller, C. G. (inventor)

1977-01-01

202

Apparatus and method of geothermal energy conversion  

Microsoft Academic Search

A system for converting the heat energy of geothermal brine to useful work uses steam from flashed brine to vaporize distilled water in heat exchangers to produce steam to drive a turbine which operates a generator to produce electric power. Before the distillate reaches the heat exchanger, it is preheated as it flows through a series of flash chambers countercurrent

L. Awerbuch; A. N. Rogers

1979-01-01

203

Apparatus and method of geothemal energy conversion  

Microsoft Academic Search

A system using a number of flash chambers for converting the heat energy of geothermal brine to useful work is disclosed. The system uses steam from flashed brine to vaporize a portion of distilled water or distillate in one or more heat exchangers to produce steam to drive a turbine which, in turn, operates a generator or the like to

A. N. Rogers; L. Awerbuch

1979-01-01

204

Ocean Thermal Energy Conversion LUIS A. VEGA  

E-print Network

-entrainment The mixing of the water already used in the OTEC plant into the incoming warm (surface) water stream. WOA05 State of the Art 10- MW CC-OTEC Pilot Plant Site Selection Criteria for OTEC Plants OTEC Economics make available to its customers. Baseload plant An energy plant devoted to the production of baseload

205

Pin stack array for thermoacoustic energy conversion  

Microsoft Academic Search

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

Robert M. Keolian; Gregory W. Swift

1995-01-01

206

Energy Conversion At The Earth's Magnetopause Using Single And Multi-Spacecraft Methods  

NASA Astrophysics Data System (ADS)

We present a small statistical data set, where we investigate energy conversion at the magnetopause using Cluster measurements of magnetopause crossings. The Cluster observations of magnetic field, plasma velocity, current density and magnetopause orientation are needed to infer the energy conversion at the magnetopause. These parameters can be inferred either from accurate multi spacecraft methods, or by using single-spacecraft methods. Our final aim is a large statistical study, for which only single-spacecraft methods can be applied. The Cluster mission provides an opportunity to examine and validate single-spacecraft methods against the multi-spacecraft methods. For single-spacecraft methods, we use the Generic Residue Analysis (GRA) and a standard one-dimensional current density method using magnetic field measurements. For multi-spacecraft methods, we use triangulation (Constant Velocity Approach - CVA) and the curlometer technique. We find that in some cases the single-spacecraft methods yield a different sign for the energy conversion than compared to the multi-spacecraft methods. These sign ambiguities arise from the orientation of the magnetopause, choosing the interval to be analyzed, large normal current and time offset of the current density inferred from the two methods. By using the Finnish Meteorological Institute global MHD simulation GUMICS-4, we are able to determine which sign is likely to be correct, introducing an opportunity to correct the ambiguous energy conversion values. After correcting the few ambiguous cases, we find that the energy conversion estimated from single-spacecraft methods is generally lower by 70% compared to the multi-spacecraft methods.

Anekallu, C. R.; Palmroth, M. M.; Pulkkinen, T. I.; Haaland, S.; Lucek, E. A.; Dandouras, I. S.

2011-12-01

207

Energy conversion in Purple Bacteria Photosynthesis  

E-print Network

The study of how photosynthetic organisms convert light offers insight not only into nature's evolutionary process, but may also give clues as to how best to design and manipulate artificial photosynthetic systems -- and also how far we can drive natural photosynthetic systems beyond normal operating conditions, so that they can harvest energy for us under otherwise extreme conditions. In addition to its interest from a basic scientific perspective, therefore, the goal to develop a deep quantitative understanding of photosynthesis offers the potential payoff of enhancing our current arsenal of alternative energy sources for the future. In the following Chapter, we consider the trade-off between dynamics, structure and function of light harvesting membranes in Rps. Photometricum purple bacteria, as a model to highlight the priorities that arise when photosynthetic organisms adapt to deal with the ever-changing natural environment conditions.

Felipe Caycedo-Soler; Ferney J. Rodriguez; Luis Quiroga; Guannan Zhao; Neil F. Johnson

2011-07-01

208

Energy conversion in Purple Bacteria Photosynthesis  

E-print Network

The study of how photosynthetic organisms convert light offers insight not only into nature's evolutionary process, but may also give clues as to how best to design and manipulate artificial photosynthetic systems -- and also how far we can drive natural photosynthetic systems beyond normal operating conditions, so that they can harvest energy for us under otherwise extreme conditions. In addition to its interest from a basic scientific perspective, therefore, the goal to develop a deep quantitative understanding of photosynthesis offers the potential payoff of enhancing our current arsenal of alternative energy sources for the future. In the following Chapter, we consider the trade-off between dynamics, structure and function of light harvesting membranes in Rps. Photometricum purple bacteria, as a model to highlight the priorities that arise when photosynthetic organisms adapt to deal with the ever-changing natural environment conditions.

Caycedo-Soler, Felipe; Quiroga, Luis; Zhao, Guannan; Johnson, Neil F

2011-01-01

209

Alcan's ocean thermal energy conversion (OTEC) program  

SciTech Connect

Since 1985 Alcan has been operating equipment at a test site at the National Energy Laboratory of Hawaii at Keahole Point near Kona in Hawaii. Segments of aluminum heat exchangers are exposed to surface sea water at 27{degrees} C and to water from 2000 ft down coming in at 7{degrees} C. Progress was such that in 1988 Alcan contracted GEC to design a 250 kW pilot facility. The cold deep water, suitable for air conditioning, is rich in nutrients and the hierarchy of mariculture products one might select is outlined. This paper reports that closed-cycle OTEC may be economical, practical and capable of having a significant impact upon world energy needs. It can be implemented on a small scale using revenues derived from fresh water production and mariculture.

Hron, V.; Fitzpatrick, N.P. (Alcan International Ltd., Kingston, Research and Development Centre, P.O. Box 8400, Kingston, Ontario K7L 5L9 (CA)); Hay, E. (Nisymco, 22 Stephenson, Dollard des Ormeaux, Quebec H9A 2V9 (CA)); Johnson, F.A. (GEC-Marconi Research Centre, Great Baddow, Chelmsford, Essex CM2 9HN (GB))

1991-01-01

210

3. Energy conversion, balances, efficiency, equilibrium  

E-print Network

concept: a small mass flow dm has a volume dV = dm/ (with density ) = A�dx, entering a system through area with friction to Vmax (with T1A > T1) 1A1 Heat transfer to surroundings, heat Q is area in p,V diagram The work" (A83) "Energy is the capacity to do work or produce heat" (ZZ03) �bo Akademi University | Thermal

Zevenhoven, Ron

211

The NASA program in Space Energy Conversion Research and Technology  

NASA Technical Reports Server (NTRS)

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.

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

1982-01-01

212

Advanced energy conversion concept for beamed-energy propulsion  

NASA Astrophysics Data System (ADS)

Basic research was performed on an innovative power conversion concept for trans atmospheric, beamed energy propulsion: a new class of External Surface Impulse (ESI) thrusters. This advanced thruster principle could be used for atmospheric VTOL, high acceleration, and lateral flight (e.g., short-term cruise) propulsion of Single-Stage-To-Orbit (SSTO) beam-powered shuttlecraft of the next century. Three classes of ESI thrusters were initially examined: (1) simple thermal, (2) electrostatic, and (3) electromagnetic. Beam power wavelengths from 10 cm (microwave) to 0.3 micron (laser) were considered. The subsequent effort concentrated on the simple thermal repetitively-pulsed ESI thrusters, energized with laser power and using air as the working fluid. Laser frequencies were selected because of the relative wealth of experimental data and theoretical research on laser impulse coupling existing in the literature. The first year analytical effort has proven conclusively that such an engine can deliver high levels of thrust-to-beam-power at liftoff (e.g., at least an order of magnitude greater than beam-powered hydrogen-fueled rockets), with infinite specific impulse (decreased only, perhaps, by ablation of the thruster surface). Later along an orbital trajectory, the primary propulsion function would transition to other modes; upon leaving the atmosphere, the SSTO vehicle would continue in a pure rocket mode.

Myrabo, Leik N.

1987-08-01

213

Efficient Energy Conversion of the 14 MeV Neutrons in DT Inertial Confinement Fusion  

NASA Astrophysics Data System (ADS)

In DT fusion 80 % of the energy released goes into 14 MeV neutrons, and only the remaining 20 % into charged particles. Unlike the charged particles, the uncharged neutrons cannot be confined by a magnetic field, and for this reason cannot be used for a direct conversion into electric energy. Instead, the neutrons have to be slowed down in some medium, heating this medium to a temperature of less than 103 K, with the heat removed from this medium to drive a turbo-generator. This conversion of nuclear into electric energy has a Carnot efficiency of about 30 %. For the 80 % of the energy released into neutrons, the efficiency is therefore no more than 24 %. While this low conversion efficiency cannot be overcome in magnetic confinement concepts, it can be overcome in inertial confinement concepts, by surrounding the inertial confinement fusion target with a sufficiently thick layer of liquid hydrogen and a thin outer layer of boron, to create a hot plasma fire ball. The hydrogen layer must be chosen just thick and dense enough to be heated by the neutrons to 100,000 K. The thusly generated, fully ionized, and rapidly expanding fire ball can drive a pulsed magnetohydrodynamic generator at an almost 100 % Carnot efficiency, or possibly be used to generate hydrocarbons.

Winterberg, F.

2013-02-01

214

Chalmers University of Technology Henrik Thunman Department of Energy Conversion  

E-print Network

Chalmers University of Technology Henrik Thunman Department of Energy Conversion ModellingSpecies http://www.entek.chalmers.se/~heth/presentation.pdf #12;Chalmers University of Technology Henrik= + x u t 0= + x u t 0= + x u t Mass change in a volume depends on the flow in and out

215

Proceedings of the 27th intersociety energy conversion engineering conference  

SciTech Connect

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.

Not Available

1992-01-01

216

Limiting efficiencies for photovoltaic energy conversion in multigap systems  

Microsoft Academic Search

Multigap systems are better matched to the sun's spectrum than single gap systems and are, therefore, more efficient as photovoltaic converters. This paper reviews the different thermodynamic approaches used in the past for computing the limiting efficiency for the conversion of solar energy into work. Within this thermodynamic context, the limit ranges from 85.4% to 95.0% depending on the assumptions

Antonio Martí; Gerardo L. Araújo

1996-01-01

217

A Morphing Blade for Wave and Wind Energy Conversion  

Microsoft Academic Search

The paper introduces a morphing blade for the application of wave and wind energy conversion. The most common and typical wave turbine, the Wells turbine, is symmetrical but rigid, whereas wind turbine blades are asymmetrical with some intended (adaptive) or unintended flexibility. Unlike the Wells turbine which is rigid, the morphing blade is flexible, allowing chord-wise bend from the leading

A. Beyene; J. Peffley

2007-01-01

218

Estimation of wind characteristics at potential wind energy conversion sites  

Microsoft Academic Search

A physically based three-dimensional computer model which can provide estimates of wind characteristics needed to assess sites for wind energy conversion systems is presented. The model incorporates the effect of underlying terrain and uses conventional wind information from selected weather stations in the area of the site. The required statistical wind characteristics are estimated from the hourly winds synthesized by

C. M. Bhumralkar; F. L. Ludwig; R. L. Mancuso

1978-01-01

219

Wind energy conversion system simulator using variable speed induction motor  

Microsoft Academic Search

The conventional synchronous generator in wind energy conversion system are now getting replaced by variable speed induction generator to extract maximum power with wide range of wind speed limit. The design and performance of such system are required a simplified digital simulator, especially for development of optimal control solutions. The proposed work is to make a prototype of an variable

S. W. Mohod; M. V. Aware

2010-01-01

220

Solar Program Assessment: Environmental Factors - Ocean Thermal Energy Conversion.  

ERIC Educational Resources Information Center

This report presents the environmental problems which may arise with the further development of Ocean Thermal Energy Conversion, one of the eight Federally-funded solar technologies. To provide a background for this environmental analysis, the history and basic concepts of the technology are reviewed, as are its economic and resource requirements.…

Energy Research and Development Administration, Washington, DC. Div. of Solar Energy.

221

Efficiency Evaluation in Grid Connected Photovoltaic Energy Conversion Systems  

Microsoft Academic Search

This paper introduces a comparative study of efficiency for topologies in photovoltaic energy conversion systems. In special, a study of losses is presented and the methodology is used to compare different topologies for grid connected photovoltaic systems in such a way that can be chosen the option of best efficiency. The systems are also tested with photovoltaic generation as well

M. C. Cavalcanti; G. M. S. Azevedo; B. A. Amaral; K. C. de Oliveira; F. A. S. Neves; Z. D. Lins

2005-01-01

222

Calibration of sonic flowmeters for Ocean Thermal Energy Conversion (OTEC)  

Microsoft Academic Search

Scientists at the Naval Coastal Systems Center (NCSC) at Panama City, Florida, have used a commercially available acoustic flowmeter to monitor critical flow conditions during an OTEC (Ocean Thermal Energy Conversion) funded study of the effects of biofouling on the efficiency of a prototype heat transfer system. Flowmeters of this type are particularly useful in applications requiring unimpeded flow; i.e.,

D. F. Lott; G. G. Salsman; C. E. Hodges

1980-01-01

223

Photonic design for efficient solid state energy conversion  

Microsoft Academic Search

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

Mukul Agrawal

2009-01-01

224

Acoustic energy conversion for mobile nanosensor network communication  

Microsoft Academic Search

Communication is fundamental capability of nanosesnor in medical and nanomedicine application. Communication by acoustic wave is most useful in nanosesnor mobile network. Acoustic communication between nanosensors in the mobile network has been favorable potential utilization in nanonmedicine, especially in health care, drug delivery and information processing. In this paper, we present the acoustic energy conversion between nanosensor communications that can

Mohammadjavad Abbasi Abandankeshi; Muhammad Shafie Abd Latiff

2011-01-01

225

Toroidal accelerator rotor platforms for wind energy conversion  

Microsoft Academic Search

A toroidal accelerator rotor platform (TARP) design for wind energy conversion systems (WECS) application is described and analyzed for performance and economic viability using both experimental results and analytical approaches. As an obstruction type flow concentrator and accelerator, a TARP generates low-pressure high-kinetic-wind-energy regions at its rotor disk sites. Since rotor performance is enhanced by flow augmentation, the calculated power

A. L. Weisbrich

1977-01-01

226

Engineering Molecular Transformations for Sustainable Energy Conversion  

SciTech Connect

Future strategies for sustainable energy production will undoubtedly require processes and materials that can efficiently convert renewable resources into fuels. Nature’s enzymes can exquisitely integrate highly active catalytic centers within flexible environments that can adaptively guide reactants to products with very high activities and selectivities. They are limited, however, by their stability and ability to integrate into large scale production processes. The design of more robust heterogeneous catalytic materials that mimic the performance of enzymes, however, has been hindered by our limited understanding of how such transformations proceed. The tremendous advances in ab initio quantum mechanical methods, atomistic simulations, and high performance computing that have occurred over the past two decades, however, provide unprecedented ability to track molecular transformations and how they proceed at specific sites and within particular environments. This information together with the advances in in situ spectroscopic methods that follow such transformations can begin to enable the design of atomic surface ensembles and nanoscale reaction environments. This paper provides the author’s perspective on how theory and simulation can be used to move from current onedimensional design efforts based on catalytic descriptors to the design of two-dimensional surfaces, threedimensional reaction environments, and proton-coupled electron transfer systems that mimic enzymes in the transformation of molecules.

Neurock, Matthew

2010-12-03

227

SPS energy conversion and power management workshop. Final report  

SciTech Connect

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)

Not Available

1980-06-01

228

HEDL magnetic fusion energy programs  

Microsoft Academic Search

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

D. G. Doran

1978-01-01

229

Review of electrochemical energy conversion and storage for ocean thermal and wind energy systems  

Microsoft Academic Search

Literature on the application of electrochemical storage and manufacturing processes related to ocean thermal energy conversion (OTEC) and wind energy conversion (WEC) is reviewed. Storage system requirements and capabilities are estimated through the year 1995. Fuel and capacity savings for the utility power sector are estimated for various battery storage\\/WEC scenarios. Examples of electrochemical technology applications in OTEC are reviewed.

A. R. Landgrebe; S. W. Donley

1981-01-01

230

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

E-print Network

for the degree of MASTER OF SCIENCE May 2006 Major Subject: Nuclear Engineering ANALYSIS OF A DIRECT ENERGY CONVERSION SYSTEM USING MEDIUM ENERGY HELIUM IONS A Thesis by JESSE JAMES CARTER Submitted..., William Burchill May 2006 Major Subject: Nuclear Engineering iii ABSTRACT Analysis of a Direct Energy Conversion System Using Medium Energy Helium Ions. (May 2006) Jesse James Carter, B.S., Texas A&M University Chair...

Carter, Jesse James

2006-08-16

231

Wind Energy Conversion System Analysis Model (WECSAM) computer program documentation  

NASA Astrophysics Data System (ADS)

Described is a computer-based wind energy conversion system analysis model (WECSAM) developed to predict the technical and economic performance of wind energy conversion systems (WECS). The model is written in CDC FORTRAN V. The version described accesses a data base containing wind resource data, application loads, WECS performance characteristics, utility rates, state taxes, and state subsidies for a six state region (Minnesota, Michigan, Wisconsin, Illinois, Ohio, and Indiana). The model is designed for analysis at the county level. The computer model includes a technical performance module and an economic evaluation module. The modules can be run separately or together. The model can be run for any single user-selected county within the region or looped automatically through all counties within the region. In addition, the model has a restart capability that allows the user to modify any data-base value written to a scratch file prior to the technical or economic evaluation.

Downey, W. T.; Hendrick, P. L.

1982-07-01

232

Thermoelectric Energy Conversion: Future Directions and Technology Development Needs  

NASA Technical Reports Server (NTRS)

This viewgraph presentation reviews the process of thermoelectric energy conversion along with key technology needs and challenges. The topics include: 1) The Case for Thermoelectrics; 2) Advances in Thermoelectrics: Investment Needed; 3) Current U.S. Investment (FY07); 4) Increasing Thermoelectric Materials Conversion Efficiency Key Science Needs and Challenges; 5) Developing Advanced TE Components & Systems Key Technology Needs and Challenges; 6) Thermoelectrics; 7) 200W Class Lightweight Portable Thermoelectric Generator; 8) Hybrid Absorption Cooling/TE Power Cogeneration System; 9) Major Opportunities in Energy Industry; 10) Automobile Waste Heat Recovery; 11) Thermoelectrics at JPL; 12) Recent Advances at JPL in Thermoelectric Converter Component Technologies; 13) Thermoelectrics Background on Power Generation and Cooling Operational Modes; 14) Thermoelectric Power Generation; and 15) Thermoelectric Cooling.

Fleurial, Jean-Pierre

2007-01-01

233

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

NASA Technical Reports Server (NTRS)

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.

1975-01-01

234

Quantum dot sensitized semiconductors for solar energy conversion  

Microsoft Academic Search

Metal sulfide (CdS or PbS) quantum dots were synthesized in nanoporous TiO2 films for applications in solar energy conversion devices. Sandwich type regenerative solar cells, based on the quantum dots sensitized TiO2 film, exhibit a high IPCE over visible wavelengths by optimizing the polysulfide electrolyte composition. The CdS QD shows a higher IPCE, compared to PbS, related to an increased

Hitomi Y. Akiyama; Tsukasa Torimoto; Yasuhiro Tachibana; Susumu Kuwabata

2006-01-01

235

Challenges of Iran's energy conversion agreements in future competitive market  

Microsoft Academic Search

Extensive need for electricity and lack of enough governmental resources for the development of related infrastructures forced the Iranian Government to invite private investors and to sign Energy Conversion Agreement (ECA) in the form of build–operate–transfer (BOT) and build–operate–own (BOO) contracts with them. Accordingly, electricity purchase would be based on a guaranteed price. Changes in some laws in 2007 caused

M. H. Sobhiyah; Y. Kh. Kashtiban

2008-01-01

236

Transmission and conversion of magnetoacoustic waves on the magnetic canopy in a quiet Sun region  

NASA Astrophysics Data System (ADS)

Context. We present evidence for the conversion and transmission of wave modes on the magnetic flux tubes that constitute mottles and form the magnetic canopy in a quiet Sun region. Aims: Our aim is to highlight the details and the key parameters of the mechanism that produces power halos and magnetic shadows around the magnetic network observed in H?. Methods: We use our previous calculations of the magnetic field vector and the height of the magnetic canopy, and based on simple assumptions, we determine the turning height, i.e., the height at which the fast magnetoacoustic waves reflect at the chromosphere. We compare the variation of 3, 5, and 7 min power in the magnetic shadow and the power halo with the results of a two-dimensional model on mode conversion and transmission. The key parameter of the model is the attack angle, which is related to the inclination of the magnetic field vector at the canopy height. Our analysis takes also into account that 1) there are projection effects on the propagation of waves; 2) the magnetic canopy and the turning height are curved layers; 3) waves with periods longer than 3 min only reach the chromosphere in the presence of inclined magnetic fields (ramp effect); 4) mottles in H? are canopy structures; and 5) the wings of H? contain mixed signal from low- and high-? plasma. Results: The dependence of the measured power on the attack angle follows the anticipated by the two-dimensional model very well. Long-period slow waves are channeled to the upper chromospheric layers following the magnetic field lines of mottles, while short-period fast waves penetrate the magnetic canopy and are reflected back higher, at the turning height. Conclusions: Although both magnetoacoustic modes contribute to velocity signals, making the interpretation of observations a challenging task, we conclude that conversion and transmission of the acoustic waves into fast and slow magnetoacoustic waves are responsible for forming power halos and magnetic shadows in the quiet Sun region.

Kontogiannis, I.; Tsiropoula, G.; Tziotziou, K.

2014-07-01

237

Plasmonic Nanoparticles and Their Suspensions for Solar Energy Conversion  

NASA Astrophysics Data System (ADS)

Plasmon resonance in nanoscale metallic structures has shown its ability to concentrate electromagnetic energy into sub-wavelength volumes. Metal nanostructures exhibit a high extinction coefficient in the visible and near infrared spectrum due to their large absorption and scattering cross sections corresponding to their surface plasmon resonance. Hence, they can serve as an attractive candidate for solar energy conversion. Recent papers have showed that dielectric core/metallic shell nanoparticles yielded a plasmon resonance wavelength tunable from visible to infrared by changing the ratio of core radius to the total radius. Therefore it is interesting to develop a dispersion of core-shell multifunctional nanoparticles capable of dynamically changing their volume ratio and thus their spectral radiative properties. Nanoparticle suspensions (nanofluids) are known to offer a variety of benefits for thermal transport and energy conversion. Nanofluids have been proven to increase the efficiency of the photo-thermal energy conversion process in direct solar absorption collectors (DAC). Combining these two cutting-edge technologies enables the use of core-shell nanoparticles to control the spectral and radiative properties of plasmonic nanofluids in order to efficiently harvest and convert solar energy. Plasmonic nanofluids that have strong energy concentrating capacity and spectral selectivity can be used in many high-temperature energy systems where radiative heat transport is essential. In this thesis, the surface plasmon resonance effect and the wavelength tuning ranges for different metallic shell nanoparticles are investigated, the solar-weighted efficiencies of corresponding core-shell nanoparticle suspensions are explored, and a quantitative study of core-shell nanoparticle suspensions in a DAC system is provided. Using core-shell nanoparticle dispersions, it is possible to create efficient spectral solar absorption fluids and design materials for applications which require variable spectral absorption or scattering.

Lv, Wei

238

Ocean Thermal Energy Conversion (OTEC) A New Secure Renewable Energy Source  

E-print Network

Ocean Thermal Energy Conversion (OTEC) A New Secure Renewable Energy Source For Defense load renewable energy system to achieve energy security for DoD facilities and bases Schofield Barracks and Commercial Applications 1 Dr. Ted Johnson Director of Alternative Energy Programs Development Lockheed Martin

239

Optimisation of a Small Non Controlled Wind Energy Conversion System for Stand-Alone Applications  

E-print Network

Optimisation of a Small Non Controlled Wind Energy Conversion System for Stand-Alone Applications. This article proposes a method to optimize the design of a small fixed-voltage wind energy conversion system are shown and discussed. Key words Wind energy conversion system, stand-alone application, nonlinear

Paris-Sud XI, Université de

240

A Framework for Reliability and Performance Assessment of Wind Energy Conversion Systems  

E-print Network

1 A Framework for Reliability and Performance Assessment of Wind Energy Conversion Systems proposes a framework for reliability and dynamic performance assessment of wind energy conversion systems--Reliability, Dynamic Performance, Wind Power, Wind Energy Conversion System (WECS), Doubly-Fed Induction Generator

Liberzon, Daniel

241

The State of the Art of Generators for Wind Energy Conversion Systems  

E-print Network

243 1 The State of the Art of Generators for Wind Energy Conversion Systems Y. Amirat, M. E. H. Benbouzid, B. Bensaker, R. Wamkeue and H. Mangel Abstract--Wind Energy Conversion Systems (WECS) have become of the studied generators is provided in Fig. 2. II. WIND ENERGY BACKGROUND A. Wind Power Conversion

Paris-Sud XI, Université de

242

The State of the Art of Generators for Wind Energy Conversion Systems  

E-print Network

The State of the Art of Generators for Wind Energy Conversion Systems Yassine Amirat, Mohamed Benbouzid, Bachir Bensaker and René Wamkeue Abstract--Wind Energy Conversion Systems (WECS) have become. I. INTRODUCTION Wind energy conversion is the fastest-growing source of new electric generation

Boyer, Edmond

243

Magnetic fusion energy and computers  

SciTech Connect

The application of computers to magnetic fusion energy research is essential. In the last several years the use of computers in the numerical modeling of fusion systems has increased substantially. There are several categories of computer models used to study the physics of magnetically confined plasmas. A comparable number of types of models for engineering studies are also in use. To meet the needs of the fusion program, the National Magnetic Fusion Energy Computer Center has been established at the Lawrence Livermore National Laboratory. A large central computing facility is linked to smaller computer centers at each of the major MFE laboratories by a communication network. In addition to providing cost effective computing services, the NMFECC environment stimulates collaboration and the sharing of computer codes among the various fusion research groups.

Killeen, J.

1982-01-01

244

Refractory semiconductors for high temperature thermoelectric energy conversion  

NASA Astrophysics Data System (ADS)

Thermoelectric energy conversion utilizing nuclear heat sources has been employed for several decades to generate power for deep space probes. In the past, lead telluride and, more recently, silicon-germanium alloys have been the prime choices as thermoelectric materials for this application. Currently, a number of refractory semiconductors are under investigation at the Jet Propulsion Laboratory in order to produce power sources of higher conversion efficiency and, thus, lower mass per unit of power output. Included among these materials are improved Si-Ge alloys, rare earth compounds and boron-rich borides. The criteria used to select thermoelectric materials, in general, and the above materials, in particular, will be discussed. The current state of the art and the accomplishments to date in thermoelectric materials research will be reviewed.

Wood, Charles

245

Investigation of direct solar-to-microwave energy conversion techniques  

NASA Technical Reports Server (NTRS)

Identification of alternative methods of producing microwave energy from solar radiation for purposes of directing power to the Earth from space is investigated. Specifically, methods of conversion of optical radiation into microwave radiation by the most direct means are investigated. Approaches based on demonstrated device functioning and basic phenomenologies are developed. There is no system concept developed, that is competitive with current baseline concepts. The most direct methods of conversion appear to require an initial step of production of coherent laser radiation. Other methods generally require production of electron streams for use in solid-state or cavity-oscillator systems. Further development is suggested to be worthwhile for suggested devices and on concepts utilizing a free-electron stream for the intraspace station power transport mechanism.

Chatterton, N. E.; Mookherji, T. K.; Wunsch, P. K.

1978-01-01

246

Energy conversion processes supporting advanced thermal energy storage technologies. [Particle catalyzed solar photodissociation; solid state radiative heat pump  

Microsoft Academic Search

Research that focuses on fundamental aspects of energy conversion could lead to innovative and improved energy storage technologies. Research progress in two energy conversion processes is summarized and the associated storage technologies described. These two processes are particle catalyzed solar photodissociation for thermochemical energy conversion and storage, and the controlled emission of thermal radiation using narrow-bandgap semiconductor materials.

R. J. Otto; P. Berdahl; A. J. Hunt

1986-01-01

247

Second USAID/GOI workshop on alternative energy resources and development: coal conversion and biomass conversion  

SciTech Connect

The intent of the Workshop was to review the progress of the program during the past year; to encourage US specialists to discuss with their Indian counterparts the direction and future of the program; to assess the status of the individual projects through site visits to the facilities and address any concerns or anticipated problems in meeting the objectives of each of the collaborative projects; and to provide a forum for technical exchange between US and Indian industry to understand the need for an availability of technology, products and services in the US and India in specific areas of interest in coal and biomass conversion. Separate abstracts were prepared for 17 papers for inclusion in the Energy Data Base.

Not Available

1985-01-01

248

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

SciTech Connect

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.

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

1980-01-01

249

Flywheel energy storage with superconductor magnetic bearings  

Microsoft Academic Search

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

B. R. Weinberger; L. Jr. Lynds

1993-01-01

250

Nuclear spin conversion of water inside fullerene cages detected by low-temperature nuclear magnetic resonance.  

PubMed

The water-endofullerene H2O@C60 provides a unique chemical system in which freely rotating water molecules are confined inside homogeneous and symmetrical carbon cages. The spin conversion between the ortho and para species of the endohedral H2O was studied in the solid phase by low-temperature nuclear magnetic resonance. The experimental data are consistent with a second-order kinetics, indicating a bimolecular spin conversion process. Numerical simulations suggest the simultaneous presence of a spin diffusion process allowing neighbouring ortho and para molecules to exchange their angular momenta. Cross-polarization experiments found no evidence that the spin conversion of the endohedral H2O molecules is catalysed by (13)C nuclei present in the cages. PMID:24852537

Mamone, Salvatore; Concistrè, Maria; Carignani, Elisa; Meier, Benno; Krachmalnicoff, Andrea; Johannessen, Ole G; Lei, Xuegong; Li, Yongjun; Denning, Mark; Carravetta, Marina; Goh, Kelvin; Horsewill, Anthony J; Whitby, Richard J; Levitt, Malcolm H

2014-05-21

251

Flywheel energy-storage-and-conversion system for photovoltaic applications  

Microsoft Academic Search

Efforts to develop a magnetically suspended solar photovoltaic flywheel energy storage unit for residential applications are discussed. A 1\\/10-scale prototype flywheel unit, which stores 1 kWh of energy in a 400-pound, 15-inch-diameter steel rotor at a maximum of 15,000 RPM, was designed, constructed and tested. The 1\\/10-scale prototype unit was based on a full-scale, 40-kWh residential flywheel design and was

P. O. Jarvinen

1982-01-01

252

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

NASA Astrophysics Data System (ADS)

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? is obtained, which is in good agreement with efficiencies computed via full-wave simulations.

Ali Asgarian, M.; Verboncoeur, J. P.; Parvazian, A.; Trines, R.

2013-10-01

253

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

SciTech Connect

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.

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

254

Conversion of relic gravitational waves into photons in cosmological magnetic fields  

SciTech Connect

Conversion of gravitational waves into electromagnetic radiation is discussed. The probability of transformations of gravitons into photons in presence of cosmological background magnetic field is calculated at the recombination epoch and during subsequent cosmological stages. The produced electromagnetic radiation is concentrated in the X-ray part of the spectrum. It is shown that if the early Universe was dominated by primordial black holes (PBHs) prior to Big Bang Nucleosynthesis (BBN), the relic gravitons emitted by PBHs would transform to an almost isotropic background of electromagnetic radiation due to conversion of gravitons into photons in cosmological magnetic fields. Such extragalactic radiation could be noticeable or even dominant component of Cosmic X-ray Background.

Dolgov, Alexander D.; Ejlli, Damian, E-mail: dolgov@fe.infn.it, E-mail: ejlli@fe.infn.it [Dipartimento di Fisica e Scienze della Terra, Polo Scientifico e Tecnologico-Edificio C, Università degli Studi di Ferrara, Via Saragat 1, 44122 Ferrara (Italy)

2012-12-01

255

Cogeneration from Waste Energy Streams Four Energy Conversion Systems Described  

Microsoft Academic Search

In times of rapid growth in the costs of energy of all types, renewed interest comes for cogeneration. Specifically, the recovery of waste energy has become economical and the potential for growth of cogeneration systems to utilize waste heat is high. Cogeneration systems for bottoming cycles and waste energy recovery from process streams are described. The nature of the energy

James Palmer

1981-01-01

256

Nanostructured transition metal oxides for energy storage and conversion  

NASA Astrophysics Data System (ADS)

Lithium-ion batteries, supercapacitors and photovoltaic devices have been widely considered as the three major promising alternatives of fossil fuels facing upcoming depletion to power the 21th century. The conventional film configuration of electrochemical electrodes hardly fulfills the high energy and efficiency requirements because heavy electroactive material deposition restricts ion diffusion path, and lowers power density and fault tolerance. In this thesis, I demonstrate that novel nanoarchitectured transition metal oxides (TMOs), e.g. MnO2, V2O 5, and ZnO, and their relevant nanocomposites were designed, fabricated and assembled into devices to deliver superior electrochemical performances such as high energy and power densities, and rate capacity. These improvements could be attributed to the significant enhancement of surface area, shortened ion diffusion distances and facile penetration of electrolyte solution into open structures of networks as well as to the pseudocapacitance domination. The utilization of ForcespinningRTM, a newly developed nanofiber processing technology, for large-scale energy storage and conversion applications is emphasized. This process simplifies the tedious multi-step hybridization synthesis and facilitates the contradiction between the micro-batch production and the ease of large-scale manufacturing. Key Words: Transition metal oxides, energy storage and conversion, ForcespinningRTM, pseudocapacitance domination, high rate capacity

Li, Qiang

257

Conversion of MCI to dementia: Role of proton magnetic resonance spectroscopy  

Microsoft Academic Search

Mild cognitive impairment (MCI) represents a heterogeneous group of cognitive disturbances at high risk of dementia. The amnestic subtype (aMCI) might be a prodromal state of Alzheimer's disease (AD). The aim of this study is the identification, by proton magnetic resonance spectroscopy (1H MRS), of modifications in brain metabolites able to detect subjects with aMCI at risk of conversion towards

Antonio Metastasio; Patrizia Rinaldi; Roberto Tarducci; Elena Mariani; Filippo T. Feliziani; Antonio Cherubini; Gian Piero Pelliccioli; Gianni Gobbi; Umberto Senin; Patrizia Mecocci

2006-01-01

258

Explorations of Novel Energy Conversion and Storage Systems  

NASA Astrophysics Data System (ADS)

At present, the majority of the world's energy demand is met by the consumption of exhaustible fuel supplies. Consequently, it is urgent to research and develop viable alternatives. In this dissertation, I present research that addresses fundamental questions concerning how water interacts with surfaces and solutes, with the goal of identifying novel systems for energy production and storage. Electrokinetic currents are created when moving fluid entrains charge from the diffuse portion of an electric double layer and carries that charge downstream. The potential difference that develops on either end of the channel is known as the streaming potential. Chapter 2 of this dissertation focuses on electrokinetic energy production and conversion efficiency of liquid microjets. Section 1 of Chapter 2 presents proof-of-principle research demonstrating that molecular hydrogen is generated from electrokinetic currents in liquid water microjets. Hydrogen is generated when hydrated protons are preferentially carried downstream and recombine with electrons at a grounded target electrode. Both the current and hydrogen production scale nearly quadratically with flow rate, as predicted by equations derived from simple double layer theory and fluid mechanics. The efficiency is currently very low (ca 10-6) and is limited by the low electrokinetic current (˜nA). Designs to improve this efficiency are considered. Rather than chemical conversion efficiency, Section 2 of Chapter 2 investigates the electrical conversion efficiency of liquid water microjets. Typical electrokinetic energy conversion schemes measure current or voltage via electrodes in the fluid reservoirs on either side of a channel. With this design, the streaming potential drives a current against the flow of the fluid and, consequently, limits the conversion efficiency. In contrast, liquid microjets break up into droplets before reaching the downstream electrode and this eliminates the possibility for back conduction. As a result, liquid microjets yield conversion efficiencies exceeding 10%, much larger than channel-dependent measurements (˜3%). It is the large potentials obtainable with electrokinetic currents (tens of kilovolts) that drive up the electrical conversion efficiency. Unfortunately, low currents with high voltages are inconvenient for application. Section 3 of Chapter 2 describes efforts to utilize the high voltage of electrokinetic currents by coupling light into the process. More specifically, the streaming potential is used to modify the space charge layer in a semiconductor and, consequently, the light harvesting characteristics of that semiconductor. To this end, microchannel jets fabricated out of glass and silicon were built to allow light to impinge on the current generating surface. Although plagued with inconsistent results, streaming currents were found to increase upon illumination and some channels even gave measurable responses to ambient room lights. Chapter 3 of this dissertation addresses the details of hydration of boron-oxides and sodium borohydride as studied by near edge x-ray absorption fine structure spectroscopy (NEXAFS) and associated theory. Boron-oxides and molecular hydrogen are products of borohydride hydrolysis which has been intensely studied for hydrogen storage purposes. In spite of their hydroxide moieties, boron-oxides turn out to not be strongly hydrated by water. The experimental spectra, as well as attending calculations, show no evidence for electronic coupling that would indicate strong hydrogen bonding between the boron-oxides and water. On the other hand, the NEXAFS spectrum of sodium borohydride is significantly altered by water. The experiment and calculations show strong evidence for short dihydrogen bonds between water hydrogens and borohydride hydrogens. Molecular dynamics simulations indicate that borohydride is hydrated at the tetrahedral corners and edge.

Duffin, Andrew Mark

259

Quantum coherence in photosynthesis for efficient solar-energy conversion  

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

260

Science in Focus: Transfer and Conversion of Energy  

NSDL National Science Digital Library

What happens when energy is converted from one form to another? This free one-hour professional development video for K-8 teachers explores the topic through examples of conversion between potential and kinetic energy. The video is designed so that teachers come away with an understanding that will help them engage students in their own explorations. Editor's Note: This resources offer excellent support for teachers to update content knowledge in energy conservation, important to meet revised science curriculum standards being adopted by many states. This collection is part of a larger set of video workshops published and maintained by the Annenberg Foundation. Other workshop topics in physical science include Forces and Motion, Chemistry, and Light.

2011-03-14

261

Visible light to electrical energy conversion using photoelectrochemical cells  

NASA Technical Reports Server (NTRS)

Sustained conversion of low energy visible or near i.r. light (>1.25 eV) to electrical energy has been obtained using wet photoelectrochemical cells where there are no net chemical changes in the system. Stabilization of n-type semi-conductor anodes of CdS, CdSe, CdTe, GaP, GaAs and InP to photoanodic dissolution is achieved by employing selected alkaline solutions of Na.sub.2 S, Na.sub.2 S/S, Na.sub.2 Se, Na.sub.2 Se/Se, Na.sub.2 Te and Na.sub.2 Te/Te as the electrolyte. The oxidation of (poly) sulfide, (poly)selenide or (poly)telluride species occurs at the irradiated anode, and reduction of polysulfide, polyselenide or polytelluride species occurs at the dark Pt cathode of the photoelectrochemical cell. Optical to electrical energy conversion efficiencies approaching 15% at selected frequencies have been observed in some cells. The wavelength for the onset of photocurrent corresponds to the band gap of the particular anode material used in the cell.

Wrighton, Mark S. (Inventor); Ellis, Arthur B. (Inventor); Kaiser, Steven W. (Inventor)

1983-01-01

262

Visible light to electrical energy conversion using photoelectrochemical cells  

SciTech Connect

Sustained conversion of low energy visible or near i.r. light (>1.25eV) to electrical energy has been obtained using wet photoelectrochemical cells where there are no net chemical changes in the system. Stabilization of n-type semi-conductor anodes of CdS, CdSe, CdTe, GaP, GaAs and InP to photoanodic dissolution is achieved by employing selected alkaline solutions of Na/sub 2/S, Na/sub 2/S/S, Na/sub 2/Se, Na/sub 2/Se/Se, Na/sub 2/Te and Na/sub 2/Te/Te as the electrolyte. The oxidation of (poly) sulfide, (poly)selenide or (poly)telluride species occurs at the irradiated anode, and reduction of polysulfide, polyselenide or polytelluride species occurs at the dark Pt cathode of the photoelectrochemical cell. Optical to electrical energy conversion efficiencies approaching 15% at selected frequencies have been observed in some cells. The wavelength for the onset of photocurrent corresponds to the band gap of the particular anode material used in the cell.

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

1983-11-08

263

Nanostructured Solar Irradiation Control Materials for Solar Energy Conversion  

NASA Technical Reports Server (NTRS)

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.

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

264

Photovoltaic and thermal energy conversion for solar powered satellites  

NASA Technical Reports Server (NTRS)

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

Von Tiesenhausen, G. F.

1976-01-01

265

Energy Conversion Efficiency of an Exponentially Graded Thermoelectric Material  

NASA Astrophysics Data System (ADS)

This work describes an analytical model that predicts the effects of property gradients on the energy conversion efficiency of a functionally graded thermoelectric material (FGTEM) with an exponentially varying Seebeck coefficient S, electrical resistivity ?, and thermal conductivity k. The figure-of-merit parameter, Z = S 2/( ?k), thus also varies exponentially. A closed-form solution for the temperature distribution in the FGTEM and the efficiency as a function of current density are obtained. The peak efficiency and the optimal current density are determined from the efficiency solution. It is found that the efficiency may be increased by about 30% using appropriate property gradients.

Jin, Zhi-He; Wallace, Travis T.; Lad, Robert J.; Su, Ji

2014-02-01

266

II-VI photovoltaic heterojunctions for solar energy conversion  

Microsoft Academic Search

Several different II-VI heterojunctions show possible promise for photovoltaic conversion of solar energy. Two of these are p-CdTe\\/n-CdS and p-CdTe\\/n-Zn sub 0.35Cd sub 0.65S, which have a maximum solar efficiency of 17 and 23%, respectively. Specific attention is given to the properties of p-CdTe\\/n-CdS cells prepared (1) by close-spaced vapor transport of CdTe onto single-crystal CdS, and (2) by two-source

A. L. Fahrenbruch; F. Buch; K. Mitchell; R. H. Bube; V. Vasilchenko

1974-01-01

267

Method and apparatus for testing electrochemical energy conversion devices  

NASA Technical Reports Server (NTRS)

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.

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

1996-01-01

268

Energy Conversion DevicesEnergy Conversion Devices Fuel Cell Electrocatalyst Development Program  

E-print Network

Ovonic Fuel Cell Company, LLC non-precious metal catalysts regenerative braking energy absorption catalysts for air electrodes for the ORFC * Ovonic Regenerative Fuel Cell #12;Texaco Ovonic Fuel Cell Company, LLC ECD: Fuel Cell Manufacturer Commercializing the Ovonic Regenerative Fuel CellTM Texaco

269

Investigation on energy conversion technology using biochemical reaction elements, 2  

NASA Astrophysics Data System (ADS)

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.

1994-03-01

270

Energy and data conversion circuits for low power sensory systems  

NASA Astrophysics Data System (ADS)

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.

Ghosh, Suvradip

271

An investigation of the effect of a magnetic field on the phosphate conversion coating formed on magnesium alloy  

NASA Astrophysics Data System (ADS)

In this paper, the influence of the magnetic field on the phosphate conversion coating formed on magnesium alloy has been studied by scanning ion selective electrode technique (SIET), X-rays phase-contrast radiography, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The results show that the superposition of a magnetic field during the phosphate conversion coating process can promote the generation of small hydrogen gas bubbles and accelerate their desorption. In addition, irrespective of the microstructure of the AZ91D magnesium alloy, it was found that the Mg2+ cations were distributed comparatively uniformly. A uniform smooth phosphate conversion coating could be obtained by immersion in the treatment solution when a magnetic field was applied perpendicular to the magnesium alloy. It may be expected to use magnetic field to control the formation of phosphate conversion coating on magnesium alloy.

Zhao, Ming; Li, Jianguo; He, Guangping; Xie, Honglan; Fu, Yanan

2013-10-01

272

Organic electronics on fibers for energy conversion applications  

NASA Astrophysics Data System (ADS)

Currently, there is great demand for pollution-free and renewable sources of electricity. Solar cells are particularly attractive from the standpoint of sunlight abundance. However, truly widespread adoption of solar cells is impeded by the high cost and poor scalability of existing technologies. For example, while 53,000 mi2 of 10% efficient solar cell modules would be required to supply the current U.S. energy demand, only about 50 mi2 have been installed worldwide. Organic semiconductors potentially offer a route to realizing low-cost solar cell modules, but currently suffer from low conversion efficiency. For organic-based solar cells to become commercially viable, further research is required to improve device performance, develop scalable manufacturing methods, and reduce installation costs via, for example, novel device form factors. This thesis makes several contributions to the field of organic solar cells, including the replacement of costly and brittle indium tin oxide (ITO) electrodes by inexpensive and malleable, thin metal films, and the application of external dielectric coatings to improve power conversion efficiency. Furthermore, we show that devices with non-planar geometries (e.g. organic solar cells deposited onto long fibers) can have higher efficiencies than conventional planar devices. Building on these results, we demonstrate novel fiber-based organic light emitting devices (OLEDs) that offer substantially improved color quality and manufacturability as a next-generation solid-state lighting technology. An intriguing possibility afforded by the fiber-based device architectures is the ability to integrate energy conversion and lighting functionalities with textiles, a mature, commodity-scale technology.

O'Connor, Brendan T.

273

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

NASA Astrophysics Data System (ADS)

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.

Juhasz, Albert J.; Sawicki, Jerzy T.

2004-02-01

274

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

NASA Technical Reports Server (NTRS)

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.

Juhasz, Albert J.; Sawicki, Jerzy T.

2003-01-01

275

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 ...

276

ER100/PPC184/ER200/PPC284, Fall 2014 Energy Units & Conversions, Global Energy Use  

E-print Network

1 ER100/PPC184/ER200/PPC284, Fall 2014 Energy Units & Conversions, Global Energy Use Problem Set #1 Total Points: 100 for ER110/PPC184; 120 for ER200/PPC284 Energy Units The purpose of these problems plant has a capacity factor of 0.80. (5 points) 3. [For ER200/PP284 students only] Why might

Kammen, Daniel M.

277

Beryllium pressure vessels for creep tests in magnetic fusion energy  

Microsoft Academic Search

Beryllium has interesting applications in magnetic fusion experimental machines and future power-producing fusion reactors. Chief among the properties of beryllium that make these applications possible is its ability to act as a neutron multiplier, thereby increasing the tritium breeding ability of energy conversion blankets. Another property, the behavior of beryllium in a 14-MeV neutron environment, has not been fully investigated,

Neef

1990-01-01

278

Wind energy conversion system analysis model (WECSAM) computer program documentation  

SciTech Connect

Described is a computer-based wind energy conversion system analysis model (WECSAM) developed to predict the technical and economic performance of wind energy conversion systems (WECS). The model is written in CDC FORTRAN V. The version described accesses a data base containing wind resource data, application loads, WECS performance characteristics, utility rates, state taxes, and state subsidies for a six state region (Minnesota, Michigan, Wisconsin, Illinois, Ohio, and Indiana). The model is designed for analysis at the county level. The computer model includes a technical performance module and an economic evaluation module. The modules can be run separately or together. The model can be run for any single user-selected county within the region or looped automatically through all counties within the region. In addition, the model has a restart capability that allows the user to modify any data-base value written to a scratch file prior to the technical or economic evaluation. Thus, any user-supplied data for WECS performance, application load, utility rates, or wind resource may be entered into the scratch file to override the default data-base value. After the model and the inputs required from the user and derived from the data base are described, the model output and the various output options that can be exercised by the user are detailed. The general operation is set forth and suggestions are made for efficient modes of operation. Sample listings of various input, output, and data-base files are appended. (LEW)

Downey, W T; Hendrick, P L

1982-07-01

279

Plasmadynamics and ionization kinetics of thermionic energy conversion  

SciTech Connect

To reduce the plasma arc-drop, thermionic energy conversion is studied with both analytical and numerical tools. Simplifications are made in both the plasmadynamic and ionization-recombination theories. These are applied to a scheme proposed presently using laser irradiation to enhance the ionization kinetics of the thermionic plasma and thereby reduce the arc-drop. It is also predicted that it is possible to generate the required laser light from a thermionic-type cesium plasma. The analysis takes advantage of theoretical simplifications derived for the ionization-recombination kinetics. It is shown that large laser ionization enhancements can occur and that collisional cesium recombination lasing is expected. To complement the kinetic theory, a numerical method is developed to solve the thermionic plasma dynamics. To combine the analysis of ionization-recombination kinetics with the plasma dynamics of thermionic conversion, a finite difference computer program is constructed. It is capable of solving for both unsteady and steady thermionic converter behavior including possible laser ionization enhancement or atomic recombination lasing. A proposal to improve thermionic converter performance using laser radiation is considered. In this proposed scheme, laser radiation impinging on a thermionic plasma enhances the ionization process thereby raising the plasma density and reducing the plasma arc-drop. A source for such radiation may possibly be a cesium recombination laser operating in a different thermionic converter. The possibility of this being an energy efficient process is discussed. (WHK)

Lawless, J.L. Jr.; Lam, S.H.

1982-02-01

280

Design requirements for interfaces in solar energy conversion technologies  

NASA Astrophysics Data System (ADS)

Candidate materials for improving the durability and economics of solar energy conversion systems (SECS) are reviewed. A 30-yr lifetime is regarded as necessary for solar collector and concentrator materials in order to offset the high initial costs of SECS in parabolic dish, heliostat, parabolic trough, flat plate collector, OTEC, solar cell, and wind turbine configurations. The materials are required to transfer a maximum amount of intercepted energy without degrading from exposure to UV radiation, wind, water, dust, and temperature cycling. Glass and mirrored surfaces for reflecting or refracting optical subsystems are currently made from soda-lime, boro- and aluminosilicate, and must resist chemicals, abrasion, and permeability, and have good strength, flexibility, coefficient of expansion, and Young's modulus. Additional concerns are present in photochemical, solar cell, and in substrata components and systems.

Butler, B. L.

1982-04-01

281

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

NASA Technical Reports Server (NTRS)

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.

1988-01-01

282

Controlled cellular energy conversion in brown adipose tissue thermogenesis  

NASA Technical Reports Server (NTRS)

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.

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

1978-01-01

283

Solid State Energy Conversion Alliance 2nd Annual Workshop Proceedings  

SciTech Connect

The National Energy Technology Laboratory (NETL) and the Pacific Northwest National Laboratory (PNNL) are pleased to provide the proceedings of the second annual Solid State Energy Conversion Alliance (SECA) Workshop held on March 29-30, 2001 in Arlington. The package includes the presentations made during the workshop, a list of participants, and the results of the breakout sessions. Those sessions covered stack materials and processes, power electronics, balance of plant and thermal integration, fuel processing technologies, and stack and system performance modeling. The breakout sessions have been reported as accurately as possible; however, due to the recording and transcription process errors may have occurred. If you note any significant omissions or wish to provide additional information, we welcome your comments and hope that all stakeholder groups will use the enclosed information in their planning endeavors.

National Energy Technology Laboratory

2001-03-30

284

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

NASA Astrophysics Data System (ADS)

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.

1988-03-01

285

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

SciTech Connect

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}.

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

1996-12-31

286

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

DOEpatents

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.

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

1997-12-23

287

Experimental and Analytical Studies on Pyroelectric Waste Heat Energy Conversion  

NASA Astrophysics Data System (ADS)

This study is concerned with direct conversion of thermal energy into electrical energy by subjecting pyroelectric materials to the Olsen cycle. The Olsen cycle consists of two isoelectric field and two isothermal process on the electric displacement versus electric field diagram. The energy and power generation capabilities of copolymer poly(vinylidene fluoridetrifluorethylene) [P(VDF-TrFE)] films and lead lanthanum zirconate titanate (PLZT) ceramics were evaluated by executing the Olsen cycle via so-called "stamping experiments" and "dipping experiments". The stamping experiments consisted of alternatively pressing a pyroelectric material in thermal contact with hot and cold aluminum blocks under specified electric fields. It was performed to assess the pyroelectric energy conversion performance using heat conduction. The largest energy density generated in the stamping experiments was 155 J/L/cycle with 60/40 P(VDF-TrFE) thin film at 0.066 Hz between 25 and 110°C and electric fields cycled between 20 and 35 MV/m. This energy density exceeded the 130 J/L/cycle achieved by our previous prototypical device using oscillatory laminar convective heat transfer. However, the performance was limited by poor thermal contact between the aluminum blocks and pyroelectric material and also by excessive leakage current inherent to P(VDF-TrFE) at high temperatures and/or large electric fields. On the other hand, dipping experiments consisted of successively immersing a pyroelectric material into isothermal hot and cold thermal reservoirs at different temperatures while simultaneously cycling the electric fields. It was performed on relaxor ferroelectric x/65/35 PLZT ceramics with x between 5 and 10 mol.%. The operating temperature, applied electric field, sample thickness, cycle frequency, and electrode material were systematically varied to explore their respective effects on the energy and power densities produced. A maximum energy density of 1014 J/L/cycle was obtained with a 190?m thick 7/65/35 PLZT sample at 0.0256 Hz at temperatures between 30 and 200°C and electric field from 0.2 to 7.0 MV/m. To the best of our knowledge, this energy density is the largest achieved among pyroelectric single crystals, ceramics, and polymers using the Olsen cycle. Meanwhile, a maximum power density of 55.3 ± 8.0 W/L obtained with a 190?m thick 9.5/65/35 PLZT sample at 0.125 Hz. Additionally, the temperature-dependent dielectric behavior of PLZT ceramics were characterized. The polarization transition temperature of lanthanum-doped x /65/35 PLZT ceramics decreased from 240 to 10°C for increasing lanthanum dopant concentration x from 5 to 10 mol.%. This establishes that the different compositions should be operated at different temperatures for maximum pyroelectric energy conversion. Finally, a physical thermo-electrical model for estimating the energy harvested by ferroelectric relaxors was further validated against experimental data for a wide range of electric fields and temperatures.

Lee, Felix

288

Understanding and tuning nanostructured materials for chemical energy conversion  

NASA Astrophysics Data System (ADS)

The conversion of energy that employs chemical reaction is termed chemical energy conversion. In my dissertation, I have focused on chemical energy conversion systems involving energetic materials and lithium ion batteries, where performance is strongly dependent on the properties of materials and their architecture. The objective of this study is to enhance our understanding and tuning of nanostructured materials that might find application toward energetic materials and electrode materials in lithium ion batteries. Rapid heating diagnostics tools, i.e. temperature-jump techniques, have been used to study the ignition of aluminum nanoparticles, nanothermite reaction mechanism and metal oxides nanoparticles decomposition under rapid heating conditions (˜105-106 K/s). Time-resolved mass spectra results support the hypothesis that Al containing species diffuse outwards through the oxide shell. Low effective activation energies were found for metal oxides nanoparticles decomposition at high heating rates, implying the mass transfer control at high heating rates. The role of oxygen release from oxidizer in nanothermite reactions have been examined for several different systems, including some using microsized oxidizer (i.e., nano-Al/micro-I 2O5). In particular, for periodate based nanothermites, direct evidence from high heating rate SEM and mass spectrometry results support that direct gas phase oxygen release from oxidizer decomposition is critical in its ignition and combustion. Efforts have also been made to synthesize nanostructured materials for nanoenergetic materials and lithium ion batteries applications. Hollow CuO spheres were synthesized by aerosol spray pyrolysis, employing a gas blowing mechanism for the formation of hollow structure during aerosol synthesis. The materials synthesized as oxidizers in nanothermite demonstrated superior performance, and of particular note, periodate salts based nanothermite demonstrated the best gas generating performance for nanothermite materials. Energetic composite nanofibrous mats (NC/Al-CuO, NC/Al-Fe2O3, and NC/Al-Bi2O3) were also prepared by an electrospinning method and evaluated for their combustion performance. Aerosol spray pyrolysis was employed to produce carbon coated CuO hollow spheres, Mn3O4 hollow spheres, and Fe2O 3 mesoporous spheres. These hollow/mesoporous spheres demonstrated superior electrochemical performance when used as anode materials in lithium ion batteries. The effects of the amorphous and crystal structures on the electrochemical performance and the structure evolution during electrochemical tests were also investigated.

Jian, Guoqiang

289

The Status of Thermophotovoltaic Energy Conversion Technology at Lockheed Martin Corporation  

Microsoft Academic Search

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

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

2004-01-01

290

Proceedings of the 30. intersociety energy conversion engineering conference. Volume 1  

Microsoft Academic Search

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

D. Y. Goswami; L. D. Kannberg; S. Somasundaram; T. R. Mancini

1995-01-01

291

Discovery Research in Magnetic Fusion Energy  

E-print Network

Discovery Research in Magnetic Fusion Energy or "How we learn about magnetic containment ! The slides for this talk are online at: http://www.apam.columbia.edu/mauel/mauel_pubs/NUF2014-Discovery" axisymmetric magnetic confinement � Fusion energy needs discoveries to overcome challenges to economic

Mauel, Michael E.

292

Flywheel energy storage. II - Magnetically suspended superflywheel  

Microsoft Academic Search

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

J. A. Kirk; P. A. Studer

1977-01-01

293

Energy transfer processes in solar energy conversion. Progress report  

Microsoft Academic Search

We have made substantial progress in experimental and theoretical studies in two areas: Photoinduced donor to acceptor electron transfer followed by back transfer in random solutions; and electronic excitation transport in systems with complex inhomogeneous spatial geometries and inhomogeneous energy distributions. Through the development of accurate statistical mechanical theories, we have been able to relate dynamics in complex systems to

Fayer

1989-01-01

294

Numerical analysis of magnetic field in superconducting magnetic energy storage  

SciTech Connect

This paper reports that the superconducting magnetic energy storage (SMES) is more useful than the other systems of electric energy storage because of larger stored energy and higher efficiency. The other systems are the battery, the flywheel, the pumped-storage power station. Some models of solenoid type SMES are designed in U.S.A. and Japan. But a high magnetic field happens by the large scale SMES in the living environment, and makes the erroneous operations of the computer display, the pacemaker of the heart and the electronic equipments. We study some fit designs of magnetic shielding of the solenoidal type SMES for reduction of the magnetic field in living environment. When some superconducting shielding coils are over the main storage coil, magnetic field reduces remarkably than the case of non shielding coil. The calculated results of the magnetic field are obtained y the finite element method.

Kanamaru, Y. (Kanazawa Inst. of Technology, 7-1 Ohgigaoka, Nonoichi, Ishikawa 921 (JP)); Amemiya, Y. (Chiba Inst. of Tech., Narashino (Japan))

1991-09-01

295

ECUT (Energy Conversion and Utilization Technologies Program). Biocatalysis Project  

NASA Technical Reports Server (NTRS)

Presented are the FY 1985 accomplishments, activities, and planned research efforts of the Biocatalysis Project of the U.S. Department of Energy, Energy Conversion and Utilization Technologies (ECUT) Program. The Project's technical activities were organized as follows: In the Molecular Modeling and Applied Genetics work element, research focused on (1) modeling and simulation studies to establish the physiological basis of high temperature tolerance in a selected enzyme and the catalytic mechanisms of three species of another enzyme, and (2) determining the degree of plasmid amplification and stability of several DNA bacterial strains. In the Bioprocess Engineering work element, research focused on (1) studies of plasmid propagation and the generation of models, (2) developing methods for preparing immobilized biocatalyst beads, and (3) developing an enzyme encapsulation method. In the Process Design and Analysis work element, research focused on (1) further refinement of a test case simulation of the economics and energy efficiency of alternative biocatalyzed production processes, (2) developing a candidate bioprocess to determine the potential for reduced energy consumption and facility/operating costs, and (3) a techno-economic assessment of potential advancements in microbial ammonia production.

1986-01-01

296

Control policies for wind-energy conversion systems  

NASA Astrophysics Data System (ADS)

Wind energy is usually converted into electrical energy through a wind rotor driving a generator. It is well known that maximum conversion efficiency occurs when the wind rotor is loaded in such a way that its rotational speed is allowed to fluctuate in sympathy with wind-speed variations. In the paper, the wind-rotor/generator dynamics are investigated for a number of control policies, and it is shown that the system response is a function of wind speed. Owing to this relationship, control strategies based on static optimum matching premises are unlikely to be optimal under continuously changing conditions. To prove this hypothesis, the aerogenerator dynamics were simulated on an analogue computer, and, for a given recorded windspeed sample, the energy delivered was measured for a number of control strategies. The results indicate that, for the wind sample used and aerogenerator simulated, sophisticated control policies do not necessarily result in maximum energy yield. An attempt is made to interpret this paradox in terms of the system dynamics.

Buehring, I. K.; Freris, L. L.

1981-09-01

297

ECUT (Energy Conversion and Utilization Technologies Program). Biocatalysis Project  

NASA Astrophysics Data System (ADS)

Presented are the FY 1985 accomplishments, activities, and planned research efforts of the Biocatalysis Project of the U.S. Department of Energy, Energy Conversion and Utilization Technologies (ECUT) Program. The Project's technical activities were organized as follows: In the Molecular Modeling and Applied Genetics work element, research focused on (1) modeling and simulation studies to establish the physiological basis of high temperature tolerance in a selected enzyme and the catalytic mechanisms of three species of another enzyme, and (2) determining the degree of plasmid amplification and stability of several DNA bacterial strains. In the Bioprocess Engineering work element, research focused on (1) studies of plasmid propagation and the generation of models, (2) developing methods for preparing immobilized biocatalyst beads, and (3) developing an enzyme encapsulation method. In the Process Design and Analysis work element, research focused on (1) further refinement of a test case simulation of the economics and energy efficiency of alternative biocatalyzed production processes, (2) developing a candidate bioprocess to determine the potential for reduced energy consumption and facility/operating costs, and (3) a techno-economic assessment of potential advancements in microbial ammonia production.

1986-07-01

298

Magnetic Resonance Studies of Energy Storage Materials  

NASA Astrophysics Data System (ADS)

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.

Vazquez Reina, Rafael

299

Second USAID/GOI workshop on alternative energy resources and development: coal conversion and biomass conversion  

SciTech Connect

Papers describing progress in coordinated research programs between India and the USA were presented in sessions with the following headings: combustion; coal preparation and gas cleanup; and biomass conversion. 9 of the papers have been abstracted separately.

Not Available

1985-01-01

300

Calibration of sonic flowmeters for Ocean Thermal Energy Conversion (OTEC)  

SciTech Connect

A commercially available acoustic flowmeter has been used to monitor critical flow conditions relative to the effects of biofouling on the efficiency of a prototype heat transfer system during the OTEC (Ocean Thermal Energy Conversion) funded study. The special procedures devised to calibrate the flowmeters are documented. The calibration consisted of pumping seawater through the flowmeter into a tank suspended beneath a special load cell which provided an output voltage proportional to the weight of water in the tank. A programmable desktop calculator system was used to monitor changes in voltage as a function of time, and convert these changes into flow rates for direct comparison with values read from the sonic flowmeter's digital display. Calibration checks were made at metered flows of 8, 10, 12, 14, 16, and 18 gallons per minute (gpm). It was found that computed flows were essentially linear but differed from metered values by as much as 9.0%.

Lott, D.F.; Salsman, G.G.; Hodges, C.E.

1980-12-01

301

Standards for photovoltaic energy conversion systems. Final report  

SciTech Connect

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.

Schafft, H. A.

1980-04-01

302

Photochemical energy conversion by membrane-bound photoredox systems  

SciTech Connect

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.

Tollin, G.

1992-03-01

303

Power conversion system utilizing reversible energy of liquefied natural gas  

SciTech Connect

A power conversion system comprising a combination of a liquefied natural gas vaporizing plant and a fuel burning power generating facility is disclosed. The liquefied natural gas vaporizing plant utilizes the cryogenic capacity of the liquefied natural gas to produce liquid air which is pumped to a high pressure by a liquid air pump. The liquid air is then brought into a heat exchanging relationship with air drawn into the vaporizing plant so that the high pressure liquid air is converted to high pressure gaseous air. The high pressure gaseous air which represents recovered reversible energy of the liquefied natural gas is fed into a combustion chamber of the fuel burning power generating plant. Since the power generating facility requires no significant output of power to drive a compressor to compress ambient air prior to its entry into the combustion chamber, the power generating facility is operated at a high efficiency.

Hoskinson, R.L.

1982-05-18

304

Tandem photovoltaic solar cells and increased solar energy conversion efficiency  

NASA Technical Reports Server (NTRS)

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

Loferski, J. J.

1976-01-01

305

Monolithic Interconnected Modules (MIMs) for Thermophotovoltaic Energy Conversion  

NASA Technical Reports Server (NTRS)

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.

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

2003-01-01

306

Feasibility study of reed, Phragmites australis, biomass energy conversion  

SciTech Connect

Phragmites is a widely distributed, highly productive grass occupying a variety of habitats in the Region III Atlantic Coastal Plain. Information, largely from the foreign literature, suggests that seasonal nutrient cycles within the plant, as well as changes in the plant's composition between terrestrial and aquatic habitats may be important influences on the nutritional value and palatibility of Phragmites to consuming organisms. Although direct grazing of Phragmites is apparently quite limited, the plant seems to be an important contributor to detrital food webs in aquatic habitats. It is precisely these characteristics of the Phragmites habitat (internal nutrient recycling and limited wildlife value on terrestrial sites) that, along with its record productivity, makes this plant an almost ideal candidate species for biomass harvesting and energy conversion.

Drifmeyer, J.E.

1980-01-01

307

Performance assessment and cost effectiveness of wind energy conversion systems  

NASA Astrophysics Data System (ADS)

Performance and cost characteristics of wind energy conversion systems (WECS) are assessed. Both technological and cost-effectiveness considerations are discussed for these systems with emphasis on developing appropriate economic measures for the application of electric power generation. A cost-effectiveness analysis is developed for target costs per unit frontal area for such systems showing the influence of annual mean windspeed, tower height, atmospheric boundary layer stability, capital-cost financing rates, and the cost escalation rate of the fossil fuel displaced. The latter two parameters are particularly sensitive ones in assessing both lifetime cost-effectiveness and payback time. Although allowable costs vary be several orders of magnitude, initial target costs for cost-effectiveness seem to be of the order of $50 to $400/sq m of frontal area.

Miller, G.; Hoffert, M.; Corren, D.

1982-04-01

308

Energy Magnetization and the Thermal Hall Effect  

NASA Astrophysics Data System (ADS)

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.

Qin, Tao; Niu, Qian; Shi, Junren

2011-12-01

309

Energy magnetization and the thermal Hall effect.  

PubMed

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

Qin, Tao; Niu, Qian; Shi, Junren

2011-12-01

310

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

E-print Network

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...

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

2014-01-01

311

High Energy Utilization, CoGeneration Nuclear power Plants With Static Energy Conversion  

Microsoft Academic Search

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,

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

2002-01-01

312

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

NASA Astrophysics Data System (ADS)

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-toelectrical energy conversion devices.

Hunter, Scott R.; Lavrik, Nickolay V.; Mostafa, Salwa; Rajic, Slo; Datskos, Panos G.

2012-06-01

313

Performance analysis of energy conversion via caloric effects in first-order ferroic phase transformations.  

PubMed

A finite-time thermodynamic model of ferroic refrigerators and generators, based on first order phase transformation, is given. We use this model to evaluate a novel method of converting heat directly into electricity based on the martensitic phase transformation accompanied by an abrupt change in magnetic ordering recently discovered [Srivastava et al., Adv. Energy Mater., 2011, 1, 97]. In this paper, we study the efficiency and power output of this method. The formulas of efficiency and power output in terms of material constants, design parameters, and working conditions are derived. The Clausius-Clapeyron coefficient is shown to be important to the efficiency. The figure of merit, as a dimensionless parameter, of energy conversion using the new method is introduced. It is shown that, as the figure of merit goes to infinity, the efficiency approaches the Carnot efficiency. Thermodynamic cycles of the new energy conversion method are optimized for a maximum power output. The matching criteria between materials and working temperatures of such optimized cycles are derived. Using these criteria, one can choose the most suitable materials under given working conditions, or decide the best working conditions for available materials. PMID:24836947

Song, Yintao

2014-07-01

314

Solar-chemical energy conversion via reversible liquid phase Diels-Alder reactions. Final technical report  

Microsoft Academic Search

Thermochemical energy conversion at moderate or low temperature (< about 400°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

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

1983-01-01

315

Transmission and Conversion of Energy by Coupled Soft Gears  

E-print Network

Dynamical aspects of coupled deformable gears are investigated to clarify the differences of mechanical properties between the machines consist of hard materials and those of soft materials. In particular, the performances of two functions, the transmission and the conversion of the energy, are compared between the hard and soft gears systems. First, the responses of the coupled gears against a constant torque working on one of gears are focused for two types of couplings; P) a pair gears are coupled, and T) three gears are coupled with forming a regular triangle. In systems with the coupling P), we obtain trivial results that the rotational energy can be transmitted to other gear only if these gears are hard enough. On the other hand, in systems with the coupling T), the transmission of the rotational energy to one of the other gears appears only if these gears are soft enough. Second, we show the responses of this system in which one of gears have contact with a high temperature heat bath and the other gears have contact with a 0 temperature heat bath. With the coupling T), the directional rotations appear in two gears having contact with 0 temperature heat bath. Here, the direction of these rotations change depending on the noise strength.

Akinori Awazu

2005-03-14

316

M13 bacteriophage-enabled assembly of nanocomposites : synthesis and application in energy conversion devices  

E-print Network

Lack of energy supply and non-uniform distribution of traditional energy sources, such as coal, oil, and natural gas, have brought up tremendous social issues. To solve these issues, highly efficient energy conversion ...

Dang, Xiangnan

2013-01-01

317

Energy conversion by autonomous regulation of chaos: Dynamical mechanism of loose coupling  

E-print Network

Energy conversion by autonomous regulation of chaos: Dynamical mechanism of loose coupling Naoko, the proposed mechanism is expected to be rather general and is applicable to other energy conversion problems which converts injected energy to output directional motion. The output amount is distributed broadly

Kaneko, Kunihiko

318

Sliding Mode Power Control of Variable Speed Wind Energy Conversion Systems  

E-print Network

Sliding Mode Power Control of Variable Speed Wind Energy Conversion Systems B. Beltran, T. Ahmed power generation in variable speed wind energy conversion systems (VS-WECS). These systems have two (National Renewable Energy Laboratory) wind turbine simulator FAST (Fatigue, Aerodynamics, Structures

Boyer, Edmond

319

EXTERIORS AND INTERIORS OF THE SPACE POWER RESEARCH LABORATORY SPRL - ENERGY CONVERSION LABORATORY E  

NASA Technical Reports Server (NTRS)

EXTERIORS AND INTERIORS OF THE SPACE POWER RESEARCH LABORATORY SPRL - ENERGY CONVERSION LABORATORY ECL - REDOX - RESEARCH ANALYSIS CENTER RAC - BASIC MATERIALS LABORATORY BML - VERTICAL LIFT FACILITY VLF

1980-01-01

320

Symposium on the Physical Chemistry of Solar Energy Conversion, Indianapolis American Chemical Society Meetings, Fall 2013  

SciTech Connect

The Symposium on the Physical Chemistry of Solar Energy Conversion at the Fall ACS Meeting in Indianapolis, IN (Sept. 8-12) featured the following sessions (approx. 6 speakers per session): (1) Quantum Dots and Nanorods for Solar Energy Conversion (2 half-day sessions); (2) Artificial Photosynthesis: Water Oxidation; (3) Artificial Photosynthesis: Solar Fuels (2 half-day sessions); (4) Organic Solar Cells; (5) Novel Concepts for Solar Energy Conversion (2 half-day sessions); (6) Emerging Techniques for Solar Energy Conversion; (7) Interfacial Electron Transfer

Lian, Tianquan [PI, Emory Univ.

2013-09-01

321

Flywheel energy-storage-and-conversion system for photovoltaic applications  

NASA Astrophysics Data System (ADS)

Efforts to develop a magnetically suspended solar photovoltaic flywheel energy storage unit for residential applications are discussed. A 1/10-scale prototype flywheel unit, which stores 1 kWh of energy in a 400-pound, 15-inch-diameter steel rotor at a maximum of 15,000 RPM, was designed, constructed and tested. The 1/10-scale prototype unit was based on a full-scale, 40-kWh residential flywheel design and was a total system in that it included all the electrical features needed for a complete interface between a photovoltaic array and a residential or utility load. Design features of the unit, such as its magnetic bearing, motor-generator, rotor and output power-conditioning equipment, are described and test results are presented. Manufacturing cost studies of the full-scale, 40-kWh residential flywheel system are reported along with user worth studies of flywheel systems in the Northeast and Southwest. The 1/10-scale prototype test setup was modified into an advanced prototype flywheel test unit.

Jarvinen, P. O.

1982-03-01

322

Advanced Energy Conversion Technologies and Architectures for Earth and Beyond  

NASA Technical Reports Server (NTRS)

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.

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

2006-01-01

323

Intelligent control of a class of wind energy conversion systems  

SciTech Connect

This paper discusses the control problem for a class of wind energy conversion systems (WECS). It first develops a detailed model and then compares among four control algorithms based on conventional and intelligent control theories. A simple PI conventional controller for the exciter loop is carried out by using a first order model. When the system operating points change, the PI controller fails to provide sufficient damping or acceptable performance. Therefore both a fuzzy voltage and a fuzzy power regulators are introduced. Also a conventional adaptive pitch controller is proposed to adjust the pitch angle of the rotor blades in order to maximize the energy capture and reduce the mechanical loads. As an alternative to this controller, a neural network controller is also designed. Using the existing nonlinear wind model and the different control algorithms, the dynamic behavior of the controlled (WECS) is simulated. By selecting convenient wind data, the system characteristics such as its tracking performance, its robustness, and its ability to recover from large disturbances are studied and discussed.

Chedid, R.; Mrad, F.; Basma, M.

1999-12-01

324

Modeling the Q-cycle mechanism of transmembrane energy conversion  

E-print Network

The Q-cycle mechanism plays an important role in the conversion of the redox energy into the energy of the proton electrochemical gradient across the biomembrane. The bifurcated electron transfer reaction, which is built into this mechanism, recycles one electron, thus, allowing to translocate two protons per one electron moving to the high-potential redox chain. We study a kinetic model of the Q-cycle mechanism in an artificial system which mimics the bf complex of plants and cyanobacteria in the regime of ferredoxin-dependent cyclic electron flow. Using methods of condensed matter physics, we derive a set of master equations and describe a time sequence of electron and proton transfer reactions in the complex. We find energetic conditions when the bifurcation of the electron pathways at the positive side of the membrane occurs naturally, without any additional gates. For reasonable parameter values, we show that this system is able to translocate more than 1.8 protons, on average, per one electron, with a thermodynamic efficiency of the order of 32% or higher.

Anatoly Yu. Smirnov; Franco Nori

2011-06-29

325

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

SciTech Connect

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 .

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

326

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

Microsoft Academic Search

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

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

2011-01-01

327

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

NASA Technical Reports Server (NTRS)

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.

Baresi, Larry

1989-01-01

328

Direct Energy Conversion for Nuclear Propulsion at Low Specific Mass  

NASA Technical Reports Server (NTRS)

The project will continue the FY13 JSC IR&D (October-2012 to September-2013) effort in Travelling Wave Direct Energy Conversion (TWDEC) in order to demonstrate its potential as the core of a high potential, game-changing, in-space propulsion technology. The TWDEC concept converts particle beam energy into radio frequency (RF) alternating current electrical power, such as can be used to heat the propellant in a plasma thruster. In a more advanced concept (explored in the Phase 1 NIAC project), the TWDEC could also be utilized to condition the particle beam such that it may transfer directed kinetic energy to a target propellant plasma for the purpose of increasing thrust and optimizing the specific impulse. The overall scope of the FY13 first-year effort was to build on both the 2012 Phase 1 NIAC research and the analysis and test results produced by Japanese researchers over the past twenty years to assess the potential for spacecraft propulsion applications. The primary objective of the FY13 effort was to create particle-in-cell computer simulations of a TWDEC. Other objectives included construction of a breadboard TWDEC test article, preliminary test calibration of the simulations, and construction of first order power system models to feed into mission architecture analyses with COPERNICUS tools. Due to funding cuts resulting from the FY13 sequestration, only the computer simulations and assembly of the breadboard test article were completed. The simulations, however, are of unprecedented flexibility and precision and were presented at the 2013 AIAA Joint Propulsion Conference. Also, the assembled test article will provide an ion current density two orders of magnitude above that available in previous Japanese experiments, thus enabling the first direct measurements of power generation from a TWDEC for FY14. The proposed FY14 effort will use the test article for experimental validation of the computer simulations and thus complete to a greater fidelity the mission analysis products originally conceived for FY13.

Scott, John H.

2014-01-01

329

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

NASA Astrophysics Data System (ADS)

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.

Baresi, Larry

1989-03-01

330

Conversion Contraption  

NSDL National Science Digital Library

It's show time for eighth grade physical science students after a week of designing, building, and refining Conversion Contraptions. The contraptions are fun combinations of moving parts that use many forms of energy and many conversions of energy. It's t

Chahrour, Janet

2000-09-01

331

MPPT of VSCF wind energy conversion system using extremum control strategy  

Microsoft Academic Search

This paper presents the energy conversion optimization control strategy for a horizontal axis variable speed fixed pitch wind energy conversion system, which works in the partial load region. The system uses a variable speed wind turbine (VSWT), driving a squirrel-cage induction generator (SCIG) connected to a grid. Reference to the wind turbine model and its parameters are poorly known, so

Dafeng Fu; Yan Xing; Yundong Ma

2010-01-01

332

Photovoltaic effect in InSe Application to Solar Energy Conversion  

E-print Network

253 Photovoltaic effect in InSe Application to Solar Energy Conversion A. Segura, J. P. Guesdon, J are reported. Photovoltaic spectra are fitted with measured values oftransport and optical parameters. InSe is shown to be a new material with attractive characteristics for solar energy conversion. Performance

Boyer, Edmond

333

A microcontroller based automatic sun tracker combined with a new solar energy conversion unit  

Microsoft Academic Search

A microcontroller based automatic sun tracker combined with a new solar energy conversion unit is designed and implemented. The automatic sun tracker is implemented with a DC motor and a DC motor controller. The solar energy conversion unit consists of an array of solar panels, a step-up chopper, a single-phase inverter, an AC mains power source and a microcontroller based

F. Huang; D. Tien

1998-01-01

334

AC conductivity of nanoporous metal-oxide photoanodes for solar energy conversion  

E-print Network

AC conductivity of nanoporous metal-oxide photoanodes for solar energy conversion Steven J. Konezny% solar-to-electric energy conversion efficiency) exploited the large surface area of nanoporous thin for solar photoconversion is analyzed using a model based on fluctuation-induced tunneling conduction (FITC

Konezny, Steven J.

335

THE CONVERSION OF BIOMASS TO ETHANOL USING GEOTHERMAL ENERGY DERIVED FROM HOT DRY ROCK  

E-print Network

97505 THE CONVERSION OF BIOMASS TO ETHANOL USING GEOTHERMAL ENERGY DERIVED FROM HOT DRY ROCK of biomass to fuel ethanol is considerable. In addition, combining these two renewable energy resources of wedding an HDR geothermal power source to a biomass conversion process is flexibility, both in plant

336

Flywheel energy storage with superconductor magnetic bearings  

SciTech Connect

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.

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

1993-06-01

337

Ocean Thermal Energy Conversion (OTEC) Programmatic Environmental Analysis--Appendices  

SciTech Connect

The programmatic environmental analysis is an initial assessment of Ocean Thermal Energy Conversion (OTEC) technology considering development, demonstration and commercialization. It is concluded that the OTEC development program should continue because the development, demonstration, and commercialization on a single-plant deployment basis should not present significant environmental impacts. However, several areas within the OTEC program require further investigation in order to assess the potential for environmental impacts from OTEC operation, particularly in large-scale deployments and in defining alternatives to closed-cycle biofouling control: (1) Larger-scale deployments of OTEC clusters or parks require further investigations in order to assess optimal platform siting distances necessary to minimize adverse environmental impacts. (2) The deployment and operation of the preoperational platform (OTEC-1) and future demonstration platforms must be carefully monitored to refine environmental assessment predictions, and to provide design modifications which may mitigate or reduce environmental impacts for larger-scale operations. These platforms will provide a valuable opportunity to fully evaluate the intake and discharge configurations, biofouling control methods, and both short-term and long-term environmental effects associated with platform operations. (3) Successful development of OTEC technology to use the maximal resource capabilities and to minimize environmental effects will require a concerted environmental management program, encompassing many different disciplines and environmental specialties. This volume contains these appendices: Appendix A -- Deployment Scenario; Appendix B -- OTEC Regional Characterization; and Appendix C -- Impact and Related Calculations.

Authors, Various

1980-01-01

338

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

PubMed

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

Singh, Kalpana; Nowotny, Janusz; Thangadurai, Venkataraman

2013-03-01

339

Advanced materials development for fossil energy conversion applications  

SciTech Connect

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.

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

340

Calibration of sonic flowmeters for Ocean Thermal Energy Conversion (OTEC)  

NASA Astrophysics Data System (ADS)

Scientists at the Naval Coastal Systems Center (NCSC) at Panama City, Florida, have used a commercially available acoustic flowmeter to monitor critical flow conditions during an OTEC (Ocean Thermal Energy Conversion) funded study of the effects of biofouling on the efficiency of a prototype heat transfer system. Flowmeters of this type are particularly useful in applications requiring unimpeded flow; i.e., no sensor projecting into the moving fluid. Unfortunately, sonic flowmeters are somewhat difficult to calibrate and may be subject to drift. A method of calibration devised by NCSC may thus be of some interest to other users. It is the purpose of this report to document the special procedures used by test personnel to calibrate the flowmeters. Briefly, the calibration consisted of pumping sea water through the flowmeter into a tank suspended beneath a special load cell which provided an output voltage proportional to the weight of water in the tank. A programmable desktop calculator system was used to monitor changes in voltage as a function of time and convert these changes into flow rates for direct comparison with values read from the sonic flowmeter's digital display. Calibration checks were made at metered flows of 8, 10, 12, 14, 16, and 18 gallons per minute (gpm). It was found that computed flows were essentially linear but differed from metered values by as much as 9.0 percent.

Lott, D. F.; Salsman, G. G.; Hodges, C. E.

1980-12-01

341

Photochemical conversion of solar energy in the environment. Book chapter  

SciTech Connect

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.)

Zepp, R.G.

1991-01-01

342

MMMMaaaaggggnnnneeeettttiiiicccc FFFFuuuussssiiiioooonnnn EEEEnnnneeeerrrrggggyyyy MAGNETIC FUSION ENERGY  

E-print Network

FusionPlasma ScienceandTechnology Attractive Fusion Energy Previous Strategy Basic Plasma Science Innovative Concepts Science of Magnetic Fusion · The Magnetic Fusion Energy Portfolio · Science and Technology Spin Advanced Tokamaks Tokamaks NEW FUSION PROGRAM STRATEGY Portfolio of innovative concepts, including inertial

343

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

E-print Network

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 ...

Greenhut, Andrew David

2010-01-01

344

LDRD Final Report: Energy Conversion Using Chromophore-Functionalized Carbon Nanotubes.  

National Technical Information Service (NTIS)

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 photoabs...

A. Kane, A. Katzenmeyer, A. L. Vance, B. M. Wong, F. Leonard, K. L. Krafcik, T. Zifer, X. Zhou

2010-01-01

345

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

E-print Network

Energy Conversion Efficiency of Nanofluidic Batteries: Hydrodynamic Slip and Access Resistance Yu channels. INTRODUCTION Nanofluidic batteries are interesting energy generation systems for converting with this nanofluidic battery system has gained considerable attention. One of the challenges for the nanofluidic

Chang, Hsueh-Chia

346

Efficiency evaluation of oxygen enrichment in energy conversion processes  

SciTech Connect

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.

Bomelburg, H.J.

1983-12-01

347

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

SciTech Connect

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.

Shepard, Kenneth L

2013-03-31

348

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

349

IMECE2006-14594 Microchannel and Minichannel Heat Exchangers in Advanced Energy Recovery and Conversion Systems  

Microsoft Academic Search

Energy recovery is gaining importance in various industrial process applications because of rising energy costs and geopolitical uncertainties impacting basic energy supplies. Various advanced energy recovery \\/ conversion technologies will require high-performance heat transfer characteristics typical of micro- and mini-channel heat exchangers to achieve energy recovery performance targets and requirements. Initial engineering scoping studies have focused on advanced thermoelectric generator

Hendricks; Terry J

2006-01-01

350

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 acceptable or if you already have an engineering text I will point out the equivalent sections. Annual Energy.S. D.O.E: E.I.A. Annual Energy Review- Comprehensive summary of US/World Energy Projections. Class

351

Current research on thermochemical conversion of biomass at the National Renewable Energy Laboratory  

Microsoft Academic Search

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(3)Syngas conversion to mixed alcoholsIn

Robert M. Baldwin; Kimberly A. Magrini-Bair; Mark R. Nimlos; Perrine Pepiot; Bryon S. Donohoe; Jesse E. Hensley; Steven D. Phillips

2012-01-01

352

Energy Distribution in Melvin's Magnetic Universe  

E-print Network

We use the energy-momentum complexes of Landau and Lifshitz and Papapetrou to obtain the energy distribution in Melvin's magnetic universe. For this space-time we find that these definitions of energy give the same and convincing results. The energy distribution obtained here is the same as we obtained earlier for the same space-time using the energy-momentum complex of Einstein. These results uphold the usefulness of the energy-momentum complexes.

S. S. Xulu

1999-12-22

353

A twisted wire-shaped dual-function energy device for photoelectric conversion and electrochemical storage.  

PubMed

A wire-shaped energy device that can perform photoelectric conversion and electrochemical storage was developed through a simple but effective twisting process. The energy wire exhibited a high energy conversion efficiency of 6.58?% and specific capacitance of 85.03??F?cm(-1) or 2.13?mF?cm(-2), and the two functions were alternately realized without sacrificing either performance. PMID:24740877

Sun, Hao; You, Xiao; Deng, Jue; Chen, Xuli; Yang, Zhibin; Chen, Peining; Fang, Xin; Peng, Huisheng

2014-06-23

354

Magnetic bearings for inertial energy storage  

NASA Technical Reports Server (NTRS)

Advanced flywheels utilizing high strength fibers must operate at high rotational speeds and as such must operate in vacuum to reduce windage losses. The utilization of magnetic bearings in the flywheels overcome lubrication and seal problems, resulting in an energy storage system offering potential improvements over conventional electrochemical energy storage. Magnetic bearings evolved in the 1950s from the simple application of permanent magnets positioned to exert repulsive forces to the present where permanent magnets and electromagnets have been combined to provide axial and radial suspension. Further development of magnetic suspension has led to the design of a shaftless flywheel system for aerospace application. Despite the lack of proof of concept, integrated magnetic suspension in inertial storage systems can provide significant performance improvements to warrant development and tests.

Rodriguez, G. Ernest; Eakin, Vickie

1987-01-01

355

The Magnetic Free Energy in Active Regions  

NASA Technical Reports Server (NTRS)

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.

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

2001-01-01

356

Magnetic bearings for inertial energy storage  

SciTech Connect

The selection of a noncontacting bearing technique with no wear out phenomena and which is vacuum compatible which is the decisive factor in selecting magnetic bearings for kinetic energy storage was investigated. Unlimited cycle life without degradation is a primary goal. Storage efficiency is a key parameter which is defined as the ratio of the energy remaining to energy stored after a fixed time interval at no load conditions. Magnetic bearings, although noncontacting, are not perfectly frictionless in that magnetic losses due to eddy currents and hysteresis can occur. Practical magnetic bearings, however, deviate from perfect symmetry and have discontinuities and asymmetric flux paths either by design or when controlled in the presence of disturbances, which cause losses. These losses can be kept smaller in the bearings than in a high power motor/generator, however, are a significant factor in selecting the magnetic bearing type.

Studer, P.A.

1983-12-01

357

Some Problems Pertaining to the Transfer and Conversion of Energy.  

NASA Astrophysics Data System (ADS)

In part I, I study models for the prediction of the properties of mixed-valence systems. In the last few years I have studied bridged dimers of the form M-L-M, where M is the metal ion and L is the bridging ligand. Under certain conditions, two remote metal ions (separated by several Angstroms and with essentially zero d-orbital overlap) can be strongly coupled to each other via certain bridging ligands. For example the well-studied Creutz-Taube ion, a pyrazine-bridged mixed-valence dimer of ruthenium, has one unpaired electron which is completely delocalized and the Ru ions are each in an averaged valence state. In this ion, the coupling between the bridge and the metal ions is on the order of 1 eV. In discrete bridged dimers of this type, the frequency maximum and the shape of the intervalence transfer band are strongly dependent on the bridging species. This type of interaction could lead to interesting conductive properties in the extended-chain linear polymeric systems and two dimensional polymeric nets. More importantly, the system properties are controllable by chemical substitution on the bridging ligand L. In both the discrete systems and the extended systems, properties are dependent upon the electron occupation. Model Hamiltonians for these systems, which contain essential one- and two -electron terms, will be presented. The two-electron model Hamiltonian, called a Hybrid Hubbard model incorporates electron-electron repulsion and occupation dependent resonance integrals. The important interactions in the discrete systems, and their implications for extended systems, will be discussed. A simplified, easily solved version of the model is also presented and applied to a two-dimensional, antiferromagnetically coupled bridged network. It is shown that, within the framework of this simple model, an effective attractive interaction between electrons may occur. In part II, the production of work in finite time from a reservoir with finite, temperature-dependent heat capacity is studied. A model system, for which the only irreversibilities result from finite rates of heat conduction, is adopted. An approximate expression for the maximum work obtainable in finite time from such a system is derived. The path for the cycle producing the maximum work is derived for an arbitrary one-component working fluid. This path is independent of the equation of state for the working substance. The results obtained using the approximate method are compared to those obtained by an exact numerical procedure. It is shown that for H_2O(g), a common heat carrier in energy conversion systems, the optimum cycle and maximum work may be calculated easily and accurately, using a linear expression for C(T).

Gozashti, Saeed

358

Magnetic induction systems to harvest energy from mechanical vibrations  

E-print Network

This thesis documents the design process for magnetic induction systems to harvest energy from mechanical vibrations. Two styles of magnetic induction systems - magnet-through-coil and magnet-across-coils - were analyzed. ...

Jonnalagadda, Aparna S

2007-01-01

359

Hemp as a Feedstock for Biomass-to-Energy Conversion  

Microsoft Academic Search

An increase in the demand for biomass for conversion to heat by combustion is likely. The potential role for hemp in supplying this demand is discussed in this article. For hemp, key characteristics such as net calorific value, ash content, and melting behavior, and the risk of corrosion or polluting emissions, are all favorable. Low bulk density and size reduction

Bernard Rice

2008-01-01

360

High frequency wind energy conversion from the ocean  

Microsoft Academic Search

This paper presents a concept of high frequency link for offshore wind applications based on a reduced matrix converter oriented to reduce the size and volume of the elements in the nacelle. A modular approach aimed at increasing reliability of the conversion system, which can be used in series or parallel connection of the off shore grid is also presented.

A. Garce?s; M. Molinas

2010-01-01

361

Development of an efficient and innovative sun engine for solar to electrical energy conversion  

SciTech Connect

How much of the energy of a renewable source like solar is it possible to convert into work, and what is the maximum efficiency that could be obtained from that system. A growing number of investigators around the world are working on the solution to introduce efficient renewable energy conversion systems beyond contemporary conventional energy conversion systems which then may bring a technological break through for solving the energy and environmental problems. Therefore, further work is being conducted to promote the development of efficient and innovative conversion systems in Mexico, based on the large amount of renewable energy available there. Based on the trends of renewable energy conversion for reduction of irreversibilities at the design phase of an efficient renewable energy conversion system and focusing the attention on frictionless and vacuum environments, an innovative and efficient system is introduced for conversion of solar energy to electric power at the maximum allowed by the second law of thermodynamics. The main idea of the present sun engine; MAG-solar-1, is to be capable to: absorb solar energy, with the use of an efficient solar concentrator; store that energy, in a frictionless rotor-flywheel located in a nearly vacuum environment; and deliver power generation, at high competitive levels of efficiency. The target of the above mentioned solar device, from the thermodynamic point of view, is be the most efficient system when it is compared with photovoltaic solar modules for electrical generation under the same energy radiation conditions. Based on a solar module proposed efficiency of 15% (under solar concentration), and an expected high efficiency motor/generator (no hysteresis effects) up to 95%, the MAG-solar-1 system shall be at least 15.8% efficient during the process of solar to electrical energy conversion; the challenge is to produce a physical prototype.

Orosco, E.V.

1998-07-01

362

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

E-print Network

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 ...

Minnich, Austin Jerome

2011-01-01

363

Energy conversion regions as observed by Cluster in the plasma sheet  

Microsoft Academic Search

First in situ observations of the average load behavior of the plasma sheetCluster PS energy conversion observations are consistent with MHD simulationsECRs and BBFs are likely to be related, although details need to be explored

M. Hamrin; O. Marghitu; P. Norqvist; S. Buchert; M. André; B. Klecker; L. M. Kistler; I. Dandouras

2011-01-01

364

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

E-print Network

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 ...

Nikurashin, Maxim

365

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

NASA Technical Reports Server (NTRS)

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.

Lee, G.

1978-01-01

366

Chemomechanics of ionically conductive ceramics for electrical energy conversion and storage  

E-print Network

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 ...

Swallow, Jessica Gabrielle

367

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

E-print Network

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 ...

Macko, Jill Annette (Jill Annette Rowehl)

2014-01-01

368

IRON-INDUCED CHANGES IN LIGHT HARVESTING AND PHOTOCHEMICAL ENERGY CONVERSION IN EUKARYOTIC MARINE ALGAE  

EPA Science Inventory

The role of iron in regulating light harvesting and photochemical energy conversion process was examined in the marine unicellular chlorophyte Dunaliella tertiolecta and the marine diatom Phaeodactylum tricornutum. In both species, iron limitation led to a reduction in cellular c...

369

Proceedings of first USAID/GOI workshop on alternative energy resources and development: coal conversion and biomass conversion  

SciTech Connect

The purpose of the workshop was to provide a forum for the technical exchange of information between the US and India in the areas of coal/biomass conversion. The major coal areas are: fluidized-bed combustion, gas cleanup, coal-water mixtures, and coal cleaning. The major biomass areas are development of a village-level gasifier, utilization of producer gas in small engines, and development and field testing of a small wood-based gasifier engine. Twelve papers are presented in outline form only. Eleven of the papers are included with texts. The latter have been indexed separately for inclusion in the Energy Data Base. (DMC)

Not Available

1983-01-01

370

A new solar energy conversion scheme implemented using grid-tied single phase inverter  

Microsoft Academic Search

A new utility-connected photovoltaic inverter is presented in this paper. Simulation and implementation of the new solar energy conversion scheme has been demonstrated. The solar energy conversion unit consists of an array of solar panels, DC-DC converter, single-phase inverter, and AC mains power source. The inverter converts DC power generated by the photovoltaic cells into AC power and provides it

Saad Mekhilef; N. A. Rahim; A. M. Omar

2000-01-01

371

The special features of heat conversion into work in solar cell energy reemission  

Microsoft Academic Search

The absorption of radiant energy in solar cells is divided into parallel reversible and irreversible circular processes. Their\\u000a fractions correlate with the known thermodynamic limits of the efficiency of heat conversion into work provided the conversion\\u000a of solar energy is divided into antenna and work processes. (An analogue of antenna processes is the selective absorption\\u000a of solar radiation by pigment

V. I. Laptev

2006-01-01

372

Semiconductor based photoelectrochemical cells for solar energy conversion—An overview  

Microsoft Academic Search

An overview of the semiconductor based photoelectrochemical (pec) cells for solar energy conversion is presented.pec cells are of two types: photoelectrolysis cells and photovoltaic cells. The principles involved, electrode and electrode\\/electrolyte\\u000a interface characteristics, experimental methods of investigation and energy conversion efficiency are discussed in detail.\\u000a Up-to-date data on variouspec cells are also presented and discussed.

A Aruchamy; G Aravamudan; G V Subba Rao

1982-01-01

373

Thermophotovoltaic energy conversion system having a heavily doped n-type region  

DOEpatents

A thermophotovoltaic (TPV) energy conversion semiconductor device is provided which incorporates a heavily doped n-type region and which, as a consequence, has improved TPV conversion efficiency. The thermophotovoltaic energy conversion device includes an emitter layer having first and second opposed sides and a base layer in contact with the first side of the emitter layer. A highly doped n-type cap layer is formed on the second side of the emitter layer or, in another embodiment, a heavily doped n-type emitter layer takes the place of the cap layer.

DePoy, David M. (Clifton Park, NY); Charache, Greg W. (Clifton Park, NY); Baldasaro, Paul F. (Clifton Park, NY)

2000-01-01

374

Control Strategies for Smoothing of Output Power of Wind Energy Conversion Systems  

NASA Astrophysics Data System (ADS)

This article presents a control method for output power smoothing of a wind energy conversion system (WECS) with a permanent magnet synchronous generator (PMSG) using the inertia of wind turbine and the pitch control. The WECS used in this article adopts an AC-DC-AC converter system. The generator-side converter controls the torque of the PMSG, while the grid-side inverter controls the DC-link and grid voltages. For the generator-side converter, the torque command is determined by using the fuzzy logic. The inputs of the fuzzy logic are the operating point of the rotational speed of the PMSG and the difference between the wind turbine torque and the generator torque. By means of the proposed method, the generator torque is smoothed, and the kinetic energy stored by the inertia of the wind turbine can be utilized to smooth the output power fluctuations of the PMSG. In addition, the wind turbines shaft stress is mitigated compared to a conventional maximum power point tracking control. Effectiveness of the proposed method is verified by the numerical simulations.

Pratap, Alok; Urasaki, Naomitsu; Senju, Tomonobu

2013-10-01

375

Optical-to-acoustic energy conversion efficiency upon interaction of pulsed laser radiation with a liquid: II. Conversion efficiency measurement by holographic interferometry upon acoustooptic interaction  

Microsoft Academic Search

The efficiency of conversion of pulsed CO2 laser energy to acoustic energy is measured with holographic interferometry. The method suggested is simple and does not\\u000a require that fringe shifts in the interferogram be converted to local pressure values in the acoustic wave. The efficiency\\u000a measured for the thermal mechanism of energy conversion is in good agreement with analytical calculations [1

G. V. Ostrovskaya

2002-01-01

376

Diminiode thermionic energy conversion with lanthanum-hexaboride electrodes  

NASA Technical Reports Server (NTRS)

This paper presents thermionic-conversion data obtained from a variable-gap cesium diminiode with a hot-pressed, sintered lanthanum-hexaboride emitter and an arc-melted lanthanum-hexaboride collector. Performance curves cover a range of temperatures: emitter 1500 to 1700 K, collector 750 to 1000 K, and cesium reservoir 370 to 510 K. Calculated values of emitter and collector work functions and barrier index are also given.

Kroeger, E. W.; Bair, V. L.; Morris, J. F.

1978-01-01

377

Semiconductor-electrolyte photovoltaic cell energy conversion efficiency  

Microsoft Academic Search

Photocurrent and differential capacitance were measured as a function of terminal potential with CdS- and GaAs-electrolyte photovoltaic cells to determine the open-circuit voltage V-oc and the power conversion efficiency eta-p. V-oc was found to be 1.2 V for both cells. With monochromatic excitation, eta-p = 32% for the CdS cell, and eta-p = 21% for the GaAs cell. For both

Y. G. Chai; W. W. Anderson

1975-01-01

378

Diminiode thermionic energy conversion with lanthanum-hexaboride electrodes  

NASA Technical Reports Server (NTRS)

Thermionic conversion data obtained from a variable gap cesium diminiode with a hot pressed, sintered lanthanum hexaboride emitter and an arc melted lanthanum hexaboride collector are presented. Performance curves cover a range of temperatures: emitter 1500 to 1700 K, collector 750 to 1000 K, and cesium reservoir 370 to 510 K. Calculated values of emitter and collector work functions and barrier index are also given.

Kroeger, E. W.; Bair, V. L.; Morris, J. F.

1978-01-01

379

Photovoltaic energy conversion The objective of this laboratory is for you to explore the science and engineering of the conversion of  

E-print Network

from high efficiency materials. Session 1: Measure the IV characteristics of photovoltaic devicesPhotovoltaic energy conversion Objective The objective of this laboratory is for you to explore the science and engineering of the conversion of light to electricity by photovoltaic devices. Preparation

Braun, Paul

380

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

Microsoft Academic Search

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

Kelvin Tan; Syed Islam

2004-01-01

381

Potential Impacts of Hydrokinetic and Wave Energy Conversion Technologies on Aquatic Environments  

Microsoft Academic Search

A new generation of hydropower technologies, the kinetic hydro and wave energy conversion devices, offers the possibility of generating electricity from the movements of water, without the need for dams and diversions. The Energy Policy Act of 2005 encouraged the development of these sources of renewable energy in the United States, and there is growing interest in deploying them globally.

Glenn Cada; James Ahlgrimm; Michael Bahleda; Tom Bigford; Stefanie Damiani Stavrakas; Douglas Hall; Russell Moursund; Michael Sale

2007-01-01

382

Abstract--This paper addresses the problem of controlling wind energy conversion systems (WECS) which involve  

E-print Network

Abstract-- This paper addresses the problem of controlling wind energy conversion systems (WECS-inverter. The goal of control is to maximize wind energy extraction and this needs letting the wind turbine rotor wind energy extraction) only for one wind speed value depending on the considered value of turbine

Paris-Sud XI, Université de

383

Energy Conversion Application of Chemicurrents Induced in Metal-Semiconductor Nanostructured Devices  

NASA Astrophysics Data System (ADS)

Hydrogen is one the most attractive and suitable energy systems for generation of power in the future with high efficiencies and renewable properties. Nanoscale materials, because of their surface and physical properties are the promising candidates for the development of high performance energy conversion devices, essential components to ensure the efficient operation of the infrastructure and to facilitate the wide spread implementation of hydrogen technologies. This work realizes the use of solid state energy conversion concept to develop metal-semiconductor, metal-oxide architecture devices for electrolyte free conversion of chemical energy to electrical energy by hydrogen oxidation process. This investigation addresses the synthesis of these nanostructure devices by selection of suitable system material combinations, electrical and surface morphological characterization leading to the successful implementation in generation of chemicurrents. Also, the hydrogen oxidation process on each nanostructure device is elucidated with the help of corresponding mechanisms and the performance of each system developed was evaluated based on the resulting output efficiency. The two systems (metal-semiconductor and metal-oxide) realized, showed excellent chemical to electrical energy conversion abilities. Compared to metal-semiconductor nanostructure devices, metal-oxide systems exhibited better energy conversion abilities for indefinitely long duration of time at room temperature. The electron yield observed in considered metal-oxide systems can be sufficient for their use in practical applications. A continued realization of these metal-oxide systems with different material combinations would lead to more ecologically friendly and sustainable energy economics.

Dasari, Suhas Kiran

384

Design and performance evaluation of a unity power factor converter for wind energy conversion systems.  

E-print Network

??Wind turbine driven Permanent Magnet Synchronous Generators (PMSG) find increasing applications due to their numerous advantages. Small scale stand-alone wind energy systems are receiving considerable… (more)

Nirnaya Sarangan.

2012-01-01

385

MAGNETIC ENERGY PRODUCTION BY TURBULENCE IN BINARY NEUTRON STAR MERGERS  

SciTech Connect

The simultaneous detection of electromagnetic and gravitational wave emission from merging neutron star binaries would greatly aid in their discovery and interpretation. By studying turbulent amplification of magnetic fields in local high-resolution simulations of neutron star merger conditions, we demonstrate that magnetar-level ({approx}> 10{sup 16} G) fields are present throughout the merger duration. We find that the small-scale turbulent dynamo converts 60% of the randomized kinetic energy into magnetic fields on a merger timescale. Since turbulent magnetic energy dissipates through reconnection events that accelerate relativistic electrons, turbulence may facilitate the conversion of orbital kinetic energy into radiation. If 10{sup -4} of the {approx}10{sup 53} erg of orbital kinetic available gets processed through reconnection and creates radiation in the 15-150 keV band, then the fluence at 200 Mpc would be 10{sup -7} erg cm{sup -2}, potentially rendering most merging neutron stars in the advanced LIGO and Virgo detection volumes detectable by Swift BAT.

Zrake, Jonathan; MacFadyen, Andrew I. [Center for Cosmology and Particle Physics, Physics Department, New York University, New York, NY 10003 (United States)

2013-06-01

386

Updated perspective on the potential for thermionic conversion to meet 21. century energy needs  

SciTech Connect

Thermionic conversion is unique among power conversion approaches in its ability to generate power efficiently with high temperature heat rejection. This feature has made thermionics an attractive choice for space power systems; and it has substantial potential for terrestrial advanced energy conversion, if certain recently identified technological developments are realized in a low cost manner. Thermionic energy converters are well suited to a modular approach. Thermionics is a passive system without moving parts. Thermionic energy conversion is able to use heat at the highest temperatures available, and to reject waste heat at temperatures high enough to be efficiently used by other energy conversion systems. For example, a thermionic converter can utilize heat at a high temperature from a flame or other heat source, convert some of it to electricity, and deliver its waste heat at a temperature high enough to run a steam generator. The combination of the thermionic converter and steam generator could produce as much as 40% more electricity from the fuel than the steam generator alone. Other terrestrial applications include cogeneration and a possible power source for a hybrid, low-emission electric vehicle. These terrestrial applications require advances in efficiency and power density in order to operate with lower emitter temperatures than space power thermionic systems. Recently it has been shown that close spaced thermionic converters can achieve the performance goals necessary to meet these attractive new applications. The paper addresses the progress in this regard and describes approaches for engineering practical closed spaced converters for large scale applications. Clearly the potential for thermionic energy conversion is great. Every effort must now be made to use this technology to help solve the world`s energy problems. Investments in the manufacturing infrastructure necessary to make thermionic energy conversion cost effective are needed to reach this goal.

Fitzpatrick, G.O.; Britt, E.J.; Moyzhes, B. [Space Power, Inc., San Jose, CA (United States)

1997-12-31

387

Magnetic fusion energy and space development  

Microsoft Academic Search

Large-scale space development will require efficient propulsion and power systems. Magnetic fusion energy conceptual designs are surveyed and indicate that fusion could provide attractive solutions to this need. Using deuterium and helium-3 as fuel gives fusion products that are primarily charged particles and could be guided by magnetic fields to allow high efficiency. The main 21st-century source of 3 He

John F. Santarius

1989-01-01

388

Measurement of magnetic fluctuation induced energy transport  

SciTech Connect

The local electron energy flux produced by magnetic fluctuations has been measured directly in the MST reversed field pinch (over the radial range r/a > 0.75). The flux, produced by electrons traveling parallel to a fluctuating magnetic field, is obtained from correlation between the fluctuations in the parallel heat flux and the radial magnetic field. The fluctuation induced flux is large (100 kW/cm{sup 2}) in the ``core`` (r/a < 0.85) and small (< 10--30 kW/cm{sup 2}) in the edge.

Fiksel, G.; Prager, S.C.; Shen, W.; Stoneking, M.

1993-11-01

389

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

SciTech Connect

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.

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

1988-12-01

390

Optimizing the electrical energy conversion cycle of dielectric elastomer generators.  

PubMed

A strategy to control the electrical charge is developed to achieve high energy density of soft dielectric elastomer generators for energy harvesting. The strategy is analytically shown and experimentally demonstrated to produce the highest energy density ever reported for a soft generator. PMID:25113278

Shian, Samuel; Huang, Jiangshui; Zhu, Shijie; Clarke, David R

2014-10-01

391

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

E-print Network

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 ...

Yen, Bernard Chih-Hsun, 1981-

2005-01-01

392

Photoelectrochemical energy conversion at the conjugated polymer\\/redox polymer electrolyte interface  

Microsoft Academic Search

Electrically conducting polymers are interesting for use in potentially low-cost solar energy conversion, and in the early 1980s, they were studied for this application. However, progress was limited by their low conversion efficiencies, and not much work has been done recently. All-solid-state photoelectrochemical cells have been constructed using films of a conducting polymer, poly(3-octylthiophene), and a polymer electrolyte, amorphous polyethylene

Teketel Yohannes; O. Inganaes

1996-01-01

393

Novel maximum-power-point-tracking controller for photovoltaic energy conversion system  

Microsoft Academic Search

A novel maximum-power-point-tracking (MPPT) controller for a photovoltaic (PV) energy conversion system is presented. Using the slope of power versus voltage of a PV array, the proposed MPPT controller allows the conversion system to track the maximum power point very rapidly. As opposed to conventional two-stage designs, a single-stage configuration is implemented, resulting in size and weight reduction and increased

Yeong-Chau Kuo; Tsorng-Juu Liang; Jiann-Fuh Chen

2001-01-01

394

Plasmon-enhanced solar energy conversion in organic bulk heterojunction photovoltaics  

Microsoft Academic Search

Plasmon-active silver nanoparticle layers were included in solution-processed bulk-heterojunction solar cells. Nanoparticle layers were fabricated using vapor-phase deposition on indium tin oxide electrodes. Owing to the increase in optical electrical field inside the photoactive layer, the inclusion of such particle films lead to increased optical absorption and consequently increased photoconversion at solar-conversion relevant wavelengths. The resulting solar energy conversion efficiency

Anthony J. Morfa; Kathy L. Rowlen; Thomas H. Reilly; Manuel J. Romero; Jao van de Lagemaat

2008-01-01

395

Conversion of electromagnetic into acoustic energy using Sn, Au, and Cu films at low temperatures  

Microsoft Academic Search

Transverse acoustic waves were generated electromagnetically at 9 GHz using thin films of tin, gold, and copper on silicon substrates. We report measurements of the conversion efficiency alpha of electromagnetic into acoustic energy as a function of temperature and film thickness at and below 4.2 K and preliminary results at liquid-N2 temperature. The highest conversion efficiencies found at 4.2 K

A. Zemel; Y. Goldstein

1974-01-01

396

A universal electromagnetic energy conversion adapter based on a metamaterial absorber  

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

397

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

PubMed

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

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

2014-01-01

398

A universal electromagnetic energy conversion adapter based on a metamaterial absorber  

PubMed Central

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

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

2014-01-01

399

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

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

400

Potential environmental consequences of ocean thermal energy conversion (OTEC) plants. A workshop  

SciTech Connect

The concept of generating electrical power from the temperature difference between surface and deep ocean waters was advanced over a century ago. A pilot plant was constructed in the Caribbean during the 1920's but commercialization did not follow. The US Department of Energy (DOE) earlier planned to construct a single operational 10MWe Ocean Thermal Energy Conversion (OTEC) plant by 1986. However, Public Law P.L.-96-310, the Ocean Thermal Energy Conversion Research, Development and Demonstration Act, and P.L.-96-320, the Ocean Thermal Energy Conversion Act of 1980, now call for acceleration of the development of OTEC plants, with capacities of 100 MWe in 1986, 500 MWe in 1989, and 10,000 MWe by 1999 and provide for licensing and permitting and loan guarantees after the technology has been demonstrated.

Walsh, J.J. (ed.)

1981-05-01

401

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

Microsoft Academic Search

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

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

1982-01-01

402

20th intersociety energy conversion engineering conference. Volume 2  

SciTech Connect

This volume contains information on the mission and status of the DOE's battery energy storage program, the development of an advanced battery electric energy storage system for electric utility load leveling, and the aluminum-air power cell. Plastic-bonded, nonsintered nickel-cadmium batteries for submarines and the cycle life chemistry of ambient-temperature secondary lithium cells are also discussed. The development of zinc-bromine batteries for stationary energy storage, the development of a zinc-chloride battery for 10-kw electric energy storage, and sodium sulfur cells with high conductivity glass electrolytes are discussed. The recovery of lead/acid batteries from abusive deep discharge, and high rate lithium batteries safety testing for U.L. component recognition are reviewed. Enhanced energy recovery, geothermal power, and heat engine cycles are discussed. Hydrogen energy, magnetohydrodynamics and nuclear fission are examined.

Not Available

1985-01-01

403

Efficient conversion of solar energy to biomass and electricity.  

PubMed

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

Parlevliet, David; Moheimani, Navid Reza

2014-01-01

404

Generators for Wind Energy Conversion Systems: State of the Art and Coming Attractions  

Microsoft Academic Search

Wind Energy Conversion Systems (WECS) have become a focal point in the research of renewable energy sources. This paper provides then a comparative study of past and present generator technologies used in WECS. This study is based on an exhaustive review of the state of the art and on an effective comparison of the performances of the four main topologies

Y. Amirat; M. E. H. Benbouzid; B. Bensaker; R. Wamkeue

405

Control of a grid connected doubly-fed induction generators for wind energy conversion  

Microsoft Academic Search

With improved generator and turbine designs, better control techniques and low environmental impact, wind energy has emerged as a potential source of bulk power across the globe. In this paper, the authors report on the development of a variable speed controller for a doubly-fed induction generator (DFIG) based wind energy conversion system (WECS). DFIG is preferred as the generator because

Milton Kumar Das; S. Chowdhury; C. T. Gaunt

2009-01-01

406

Energy conversion between electrons and phonons in heterostructures for thermionic cooling  

SciTech Connect

The energy conversion between electrons and phonons in a heterostructure is studied for thermionic cooling by using the hot electron approximation. Calculations show that the energy exchange rate between electrons and phonons should be small for a net cooling power, and the film thickness should be in the range of micron for effective cooling.

Zeng, T.; Chen, G.

1999-07-01

407

Analysis of Energy Conversion Efficiency in Parallel and Series Hybrid Powertrains  

Microsoft Academic Search

The aim of this paper is to present a simulation and analytical analysis of the energy conversion efficiency in parallel and series hybrid powertrains. The analytical approach is based on the energy balance equations, whereas the simulation approach is based on an accurate and fast forward-facing simulation model for simulating parallel and series hybrid powertrains. A very good agreement between

Ferdinand Trenc; Samuel Rodman Opresnik

2007-01-01

408

Graphene-based photovoltaic cells for near-field thermal energy conversion  

E-print Network

Graphene-based photovoltaic cells for near-field thermal energy conversion Riccardo Messina to a photovoltaic cell can be largely enhanced because of the contribution of evanescent photons, in particular important source of energy. By approaching a photovoltaic (PV) cell3 in proximity of a thermal emitter

Paris-Sud XI, Université de

409

Conversion of chemical into mechanical energy by synthetic polymers (chemomechanical systems)  

Microsoft Academic Search

The isothermal conversion of chemical energy into mechanical work underlies the motility of living organisms. Chemomechanical systems based on synthetic polymers are the only artificial systems able to convert chemical energy directly into mechanical work. They may have potential uses where power supply is limited (e.g. under water, in space). They are considered as transducers or receptors, whereby semimicroscopic deformation

Yoshihito Osada

410

Sep 05:"Toward Computational Design of Iron-Based Chromophores for Solar Energy Conversion"  

E-print Network

Sep 05:"Toward Computational Design of Iron-Based Chromophores for Solar Energy Conversion, Department of Biochemistry, East Carolina University (Dept) Nov 21: "Taking snapshots along the solar energy and Organic-Metal Halide Perovskites for Next Generation Solar Cells" Professor Prashant Kamat, Department

Reid, Scott A.

411

Nanoscale Triboelectric-Effect-Enabled Energy Conversion for Sustainably Powering Portable Electronics  

E-print Network

-free, and green power source for wireless, portable, or implanted electronics. Mechanical energy scavenging basedNanoscale Triboelectric-Effect-Enabled Energy Conversion for Sustainably Powering Portable Electronics Sihong Wang,,§ Long Lin,,§ and Zhong Lin Wang,, * School of Materials Science and Engineering

Wang, Zhong L.

412

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

Microsoft Academic Search

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

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

2008-01-01

413

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

E-print Network

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 of the acoustic emission associated with its operation. A systematic analysis of the effects of rotor hub to tip

Frandsen, Jannette B.

414

84Unit Conversions Energy, Power, Flux Energy is measured in a number of ways depending on what property is being  

E-print Network

kilowatt- hour (1 kWh)? Problem 4 ­ How many ergs of energy are collected from a solar panel on a roof, if the sunlight provides a flux of 300 Joules/sec/meter 2 , the solar panels have an area of 27 square feet84Unit Conversions ­ Energy, Power, Flux Energy is measured in a number of ways depending on what

415

Static power conversion techniques for unique energy devices  

E-print Network

is an important new energy storage device that has some properties of a battery and a capacitor allowing it to be used in applications where attributes of both are needed. To realize the full potential of these energy sources, novel engineering strategies have...

Welch, Richard Andrew

2012-06-07

416

UTILIZATION OF PLASMA-CELL ENERGY CONVERSION IN NUCLEAR REACTORS  

Microsoft Academic Search

The plasma cell is discussed in connection with its ability to directly ; convert heat to electricity. This fact shows considerable promise as a basis ; for the design of space nuclear-electric power supplies. The cell is capable of ; transforming thermal or fission energy into electrical energy without moving ; parts, giving highly reliable power supplies. Temperatures in excess

W. A. Ranken; T. G. Frank

1960-01-01

417

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)

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.

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

1976-01-01

418

Broadband energy harvesting via magnetic coupling between two movable magnets  

NASA Astrophysics Data System (ADS)

Harvesting energy from ambient mechanical vibrations by the piezoelectric effect has been proposed for powering microelectromechanical systems and replacing batteries that have a finite life span. A conventional piezoelectric energy harvester (PEH) is usually designed as a linear resonator, and suffers from a narrow operating bandwidth. To achieve broadband energy harvesting, in this paper we introduce a concept and describe the realization of a novel nonlinear PEH. The proposed PEH consists of a primary piezoelectric cantilever beam coupled to an auxiliary piezoelectric cantilever beam through two movable magnets. For predicting the nonlinear response from the proposed PEH, lumped parameter models are established for the two beams. Both simulation and experiment reveal that for the primary beam, the introduction of magnetic coupling can expand the operating bandwidth as well as improve the output voltage. For the auxiliary beam, the magnitude of the output voltage is slightly reduced, but additional output is observed at off-resonance frequencies. Therefore, broadband energy harvesting can be obtained from both the primary beam and the auxiliary beam.

Fan, Kang-Qi; Xu, Chun-Hui; Wang, Wei-Dong; Fang, Yang

2014-08-01

419

Magnetic domain wall energy in Ni/Co superlattices  

NASA Astrophysics Data System (ADS)

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.

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

2014-12-01

420

Assessment of dynamic energy conversion systems for radioisotope heat sources  

NASA Astrophysics Data System (ADS)

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.

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

1985-06-01

421

Assessment of dynamic energy conversion systems for radioisotope heat sources  

SciTech Connect

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 I with a beginning of life (BOL) source temperature of 640 C, case II with a BOL source temperature of 745/sup 0/C, and case III with a BOL source temperature of 945/sup 0/C. The Stirling engine system was the top-ranked system of cases I and II, closely followed by the ORC systems in case I and ORC plus thermoelectrics in case II. The Brayton cycle system was top-ranked for case III, with the Stirling engine system a close second. The use of /sup 238/Pu in heat source sizes of 7500 W(t) was examined and found to be questionable because of cost and material availability and because of additional requirements for analysis of safeguards and critical mass.

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

1985-06-01

422

Harvesting UV photons for solar energy conversion applications.  

PubMed

We report the synthesis and characterization of five new donor–?–spacer–acceptor dye molecules with a diphenylamine donor, fluorene–1,2,5-oxadiazole spacers and a range of acceptor/anchor groups (carboxylic acid 1, cyanoacrylic acid 2 and 3, alcohol 4 and cyano 5) to facilitate electron injection from the excited dye into the TiO2 photoanode in dye-sensitized solar cells (DSSCs). Detailed photophysical studies have probed the dyes' excited state properties and revealed structure–property relationships within the series. Density functional theory (DFT) and time dependent DFT (TDDFT) calculations provide further insights into how the molecular geometry and electronic properties impact on the photovoltaic performance. A special feature of these dyes is that their absorption features are located predominantly in the UV region, which means the dye-sensitized TiO2 is essentially colorless. Nevertheless, DSSCs assembled from 1 and 2 exhibit photovoltaic power conversion efficiencies of ? = 1.3 and 2.2%, respectively, which makes the dyes viable candidates for low-power solar cells that need to be transparent and colorless and for applications that require enhanced harvesting of UV photons. PMID:24343589

Wielopolski, Mateusz; Linton, Katharine E; Marsza?ek, Magdalena; Gulcur, Murat; Bryce, Martin R; Moser, Jacques E

2014-02-01

423

Room temperature molten salts for advanced energy conversion and storage  

NASA Astrophysics Data System (ADS)

Very high energy density electrical power sources will be required by the Air Force for operations in space. New high performance electrolytes are being developed to enable a new generation of electrochemical power sources.

Wilkes, John S.

424

Room temperature molten salts for advanced energy conversion and storage  

Microsoft Academic Search

Very high energy density electrical power sources will be required by the Air Force for operations in space. New high performance electrolytes are being developed to enable a new generation of electrochemical power sources.

John S. Wilkes

1994-01-01

425

Solar energy conversion with hot electrons from impact ionisation  

Microsoft Academic Search

Impact ionisation in combination with carrier-carrier scattering in the absence of phonon scattering in an illuminated semiconductor leads to an energy distribution of electrons in the conduction band and of holes in the valence band which is best described by a single Fermi-distribution with no splitting of quasi-Fermi-energies, but with a temperature different from the lattice temperature. To make proper

Peter Würfel

1997-01-01

426

Flywheel energy storage. II - Magnetically suspended superflywheel  

NASA Technical Reports Server (NTRS)

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.

Kirk, J. A.; Studer, P. A.

1977-01-01

427

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

NASA Technical Reports Server (NTRS)

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.

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

1977-01-01

428

Toroidal constant-tension superconducting magnetic energy storage units  

DOEpatents

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.

Herring, J. Stephen (Idaho Falls, ID)

1992-01-01

429

Photoneutrino energy loss rates under magnetic field  

Microsoft Academic Search

The neutrino energy loss rate is calculated due to the photoneutrino process in a hot plasma, under magnetic field.\\u000a \\u000a The calculations done for low densities and relatively low temperatures may be used for astrophysical estimations in neutron\\u000a stars.

M. El-Khishen; A. El-Gowhari; M. Toubia

1975-01-01

430

Vacuum energy of a color magnetic vortex  

Microsoft Academic Search

We calculate the one loop gluon vacuum energy in the background of a color magnetic vortex for SU(2) and SU(3). We use zeta functional regularization to obtain analytic expressions suitable for numerical treatment. The momentum integration is turned to the imaginary axis and fast converging sums or integrals are obtained. We investigate numerically a number of profiles of the background.

M. Bordag

2003-01-01

431

The Effect of Magnetic Turbulence Energy Spectral  

E-print Network

ions (interstellar neutral particles entering the heliosphere and get ionized) #12;Solar windThe Effect of Magnetic Turbulence Energy Spectral Scaling on the Heating of the Solar Wind C. S. Ng), Kraichnan (1965) #12;Solar wind turbulence model The steady state solar wind turbulence model developed

Ng, Chung-Sang

432

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

NASA Technical Reports Server (NTRS)

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.

1980-01-01

433

Study of a wind energy conversion system in New Hampshire  

NASA Astrophysics Data System (ADS)

Concern over conventional energy costs and supplies is currently strong, particularly in New England region where eighty percent of the total energy is oil based; furthermore, forty percent of this region's total energy is OPEC oil. These figures contrast with national averages of forty-seven and thirteen percent, respectively (1). The quest to develop alternative and renewable energy sources indigenous to New England is understandable in light of these figures. The wind is one such source. The study of wind energy can be divided into three basic areas; these are technical, legal-institutional, and financial. The technical area encompasses collection and analysis of wind data, selection and installation of wind turbines and peripheral equipment, and operation and maintenance. The legal-institutional area encompasses the resolution of such issues as land use policies, power contracts, and state and federal regulations. The financial area encompasses the examination of investment opportunities made available by various site-machine combinations and the selling of such opportunities to the investment community.

Lockwood, J.; Kraft, G.; Pregent, G.; Smukler, L.

1981-08-01

434

Bulk single crystal ternary substrates for a thermophotovoltaic energy conversion system  

DOEpatents

A thermophotovoltaic energy conversion device and a method for making the device. The device includes a substrate formed from a bulk single crystal material having a bandgap (E.sub.g) of 0.4 eVenergy conversion device includes a host substrate formed from a bulk single crystal material and lattice-matched ternary or quaternary III-V semiconductor active layers.

Charache, Greg W. (Clifton Park, NY); Baldasaro, Paul F. (Clifton Park, NY); Nichols, Greg J. (Burnt Hills, NY)

1998-01-01

435

Bulk single crystal ternary substrates for a thermophotovoltaic energy conversion system  

DOEpatents

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.

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

1998-06-23

436

Ionic-passivated FeS2 photocapacitors for energy conversion and storage  

E-print Network

KU ScholarWorks | http://kuscholarworks.ku.edu Ionic-passivated FeS2 photocapicitors for energy conversion and storage by Maogang Gong et al. KU ScholarWorks is a service provided by the KU Libraries’ Office of Scholarly Communication & Copyright.... This is the published version of the article, made available with the permission of the publisher. The original published version can be found at the link below. Maogang Gong et al. (2013). Ionic-Passivated FeS2 Photocapacitors for Energy Conversion and Storage...

Gong, Maogang; Kirkeminde, Alec; Kumar, Nardeep; Zhao, Hui; Ren, Shenqiang

2013-08-08

437

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

PubMed

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

Sivula, Kevin

2013-01-01

438

Thermal-to-electric energy conversion using ferroelectric film capacitors  

NASA Astrophysics Data System (ADS)

The capacitive ferroelectric thermoelectric converter harvesting electrical energy through non-linear capacitance variation caused by changes in temperature is analyzed. The ferroelectric material used was the thin (0.5 ?m) Ba0.3Sr0.7TiO3 film. On the basis of experimental dependencies of the ferroelectric film permittivity on temperature ranging from 100 K to 350 K under different electric fields up to 80 V/?m, the optimum values of operating temperatures and electric field for the energy harvesting optimization were determined. For the temperature oscillations of ±15 K around room temperature and electric field about 40 V/?m, the harvested energy was estimated as 30 mJ/cm3. It is shown that the use of thin ferroelectric films for rapid capacitance variation versus temperature and microelectromechanical systems for fast temperature modulations may be a relevant solution for creation of small power scale generators for portable electronics.

Kozyrev, A. B.; Platonov, R. A.; Soldatenkov, O. I.

2014-10-01

439

Low-grade thermal energy-conversion Joule effect heat engines  

Microsoft Academic Search

Low-grade thermal energy conversion is discussed with attention to energy sources, heat engines, and potential Joule engine applications. Nitinol heat engine concepts are discussed, and the Nitinol equation-of-state surfaces and transition characteristics are indicated. Bottoming cycles are considered, the untapped low-temperature water energy sources are estimated, the heat-transfer limitation of gas phase heat engines is examined, and solid-state heat engines

W. S. Ginell; J. L. McNichols; J. S. Cory

1978-01-01

440

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

Microsoft Academic Search

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

Rajesh Duggirala; Hui Li; Amit Lal

2008-01-01

441

Abstract--In doubly fed induction generator (DFIG) based wind energy conversion systems (WECS), the DFIG is interfaced to the  

E-print Network

a popular candidate in the wind energy conversion systems (WECS) due to its advantages [2-5]. When comparedAbstract--In doubly fed induction generator (DFIG) based wind energy conversion systems (WECS of wind energy is growing rapidly and it is expected to provide ten percent of the global electricity

Pota, Himanshu Roy

442

Abstract--The use of doubly fed induction generators (DFIGs) in large wind energy conversion systems (WECS) has  

E-print Network

candidate in the wind energy conversion systems (WECS) due to its advantages [2- 5]. When compared to fixed1 Abstract--The use of doubly fed induction generators (DFIGs) in large wind energy conversion-Through, STATCOM, LVRT, VSC, RSC, GSC, Grid codes. I. INTRODUCTION HE use of wind energy is growing rapidly

Pota, Himanshu Roy

443

Parametric design studies of toroidal magnetic energy storage units  

NASA Astrophysics Data System (ADS)

Superconducting magnetic energy storage (SMES) units have a number of advantages as storage devices. Electrical current is the input, output and stored medium, allowing for completely solid-state energy conversion. The magnets themselves have no moving parts. The round trip efficiency is higher than those for batteries, compressed air or pumped hydro. Output power can be very high, allowing complete discharge of the unit within a few seconds. Finally, the unit can be designed for a very large number of cycles, limited basically by fatigue in the structural components. A small systems code was written to produce and evaluate self-consistent designs for toroidal superconducting energy storage units. The units can use either low temperature or high temperature superconductors. The coils have D shape where the conductor and its stabilizer/structure is loaded only in tension and the centering forces are borne by a bucking cylinder. The coils are convectively cooled from a cryogenic reservoir in the bore of the coils. The coils are suspended in a cylindrical metal shell which protects the magnet during rail, automotive or shipboard use. It is important to note that the storage unit does not rely on its surroundings for structural support, other than normal gravity and inertial loads. Designs are presented for toroidal energy storage units produced by the systems code. A wide range of several parameters have been considered, resulting in units storing from 1 MJ to 72 GJ. Maximum fields range from 5 T to 20 T. The masses and volumes of the coils, bucking cylinder, coolant, insulation and outer shell are calculated. For unattended use, the allowable operating time using only the boiloff of the cryogenic fluid for refrigeration is calculated. For larger units, the coils were divided into modules suitable for normal truck or rail transport.

Herring, J. Stephen

444

Aluminum as anode for energy storage and conversion: a review  

Microsoft Academic Search

Aluminum has long attracted attention as a potential battery anode because of its high theoretical voltage and specific energy. The protective oxide layer on the aluminum surface is however detrimental to the battery performance, contributing to failure to achieve the reversible potential and causing the delayed activation of the anode. By developing aluminum alloys as anodes and solution additives to

Qingfeng Li; Niels J Bjerrum

2002-01-01

445

Light-harvesting materials: Soft support for energy conversion  

NASA Astrophysics Data System (ADS)

To convert solar energy into viable fuels, coupling light-harvesting materials to catalysts is a crucial challenge. Now, the combination of an organic supramolecular hydrogel and a non-precious metal catalyst has been demonstrated to be effective for photocatalytic H2 production.

Stolley, Ryan M.; Helm, Monte L.

2014-11-01

446

The dissipation of excitation energy in methoxyflavones by internal conversion  

Microsoft Academic Search

Flavonoids are found in all higher plants, and many display strong absorption in the UVB spectral region. It has been suggested that they play a role in the protection of plants by screening cital cellular components from damaging UV radiation. Some flavonoids can effectively dissipate the absorbed energy by intramolecular proton transfer. For example, the 3-hydroxyflavones undergo excited state intramolecular

Gerald J. Smith; Kenneth R. Markham

1996-01-01

447

Beilstein-Institut Reflections on Energy Conversion in  

E-print Network

harnessing on an industrial scale normally involves heat production by combustion of fuels, followed the same way as industrial motors, i.e. that they release chemical energy as heat, which is then converted �29 ­ are not heat engines. ATP hydro- lysis is, of course, a net effect but the heat

448

Energy and momentum management of the Space Station using magnetically suspended composite rotors  

NASA Technical Reports Server (NTRS)

The research addresses the feasibility of using magnetically suspended composite rotors to jointly perform the energy and momentum management functions of an advanced manned Space Station. Recent advancements in composite materials, magnetic suspensions, and power conversion electronics have given flywheel concepts the potential to simultaneously perform these functions for large, long duration spacecraft, while offering significant weight, volume, and cost savings over conventional approaches. The Space Station flywheel concept arising out of this study consists of a composite-material rotor, a large-angle magnetic suspension (LAMS) system, an ironless armature motor/generator, and high-efficiency power conversion electronics. The LAMS design permits the application of appropriate spacecraft control torques without the use of conventional mechanical gimbals. In addition, flywheel systems have the growth potential and modularity needed to play a key role in many future system developments.

Eisenhaure, D. B.; Oglevie, R. E.; Keckler, C. R.

1985-01-01

449

Chemical Expansion: Implications for Electrochemical Energy Storage and Conversion Devices  

NASA Astrophysics Data System (ADS)

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.

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

2014-07-01

450

The phototron: A light to RF energy conversion device  

NASA Technical Reports Server (NTRS)

The phototron, a photoelectric device that converts light to radio frequency energy, is described. It is a vacuum tube, free electron, device that is mechanically similar to a reflex klystron with the hot filament cathode replaced by a large area photocathode. The device can operate either with an external voltage source used to accelerate the photoelectrons or with zero bias voltage; in which case the photokinetic energy of the electrons sustains the R.F. oscillations in the tuned R.F. circuit. One basic design of the phototron was tested. Frequencies as high as about 1 GHz and an overall efficiency of about 1% in the biased mode were obtained. In the unbiased mode, the frequencies of operation and efficiences are considerably lower. Success with test model suggests that considerable improvements are possible through design refinements. One such design refinement is the reduction of the length of the electron flight path.

Freeman, J. W.; Simons, S.

1982-01-01

451

Thermoelectric Energy Conversion Technology for High-Altitude Airships  

NASA Technical Reports Server (NTRS)

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.

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

2011-01-01

452

Conversion of municipal solid waste to energy, Jacksonville, Florida  

NASA Astrophysics Data System (ADS)

A 227 megagram per day prototype auger combustor system is described and performance tests are discussed. The system is a two chamber, starved-air incinerator so named because of the auger located within the primary chamber which tumbles and moves the waste through the system. The feasibility evaluation of resource recovery in the city of Jacksonville, Florida, involved the determination of the following: (1) the amount and characteristics of the solid waste; (2) the location and requirement of candidate energy customers and materials markets; (3) the applicable incineration/heat recovery and resource recovery technologies; and (4) the institutional, legal, and environmental requirements for constructing a facility. The marketing plan developd to define the specific steps required to employ a waste-to-energy technology in the Jacksonville area is also discussed.

Frounfelker, R.; Belencan, H.

1982-02-01

453

Conversion of ocean thermal energy with the salt cycle  

SciTech Connect

A temperature gradient exists between the top and the depths of oceans, the Salt Cycle is targeted at converting this thermal energy. The phases of certain solutions (liquid-liquid or solid-liquid) separate out at lower temperatures enabling the separation of the solute. By placing the solute behind a semipermeable membrane, at a higher temperature, an osmotic pressure can be developed. The pressure released into a turbine can generate power or may be put to other uses like desalination.

Saikia, S.

1997-07-01

454

MHD energy conversion with advanced-fuel ion beam fusion  

Microsoft Academic Search

Heavy- or light-ion accelerator drivers are especially attractive for use with advanced-fuel fusion targets due to the relatively high driver efficiency and the ability of these driver to meet larger ignition energy requirements. Previous work examined the use of a deuterium-fueled target with deuterium-tritium (D-T) spark ignition (AFLINT target) in a heavy-ion beam fusion reactor (LOTRIT) designed to minimize tritium

Miley

1986-01-01

455

New energy conversion techniques in space, applicable to propulsion  

Microsoft Academic Search

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. Hertzberg; K. C. Sun

1979-01-01

456

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

NASA Technical Reports Server (NTRS)

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.

Kann, Deirdre M.; Vincent, Dayton G.

1986-01-01

457

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

SciTech Connect

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.

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

458

Low Cost Solar Energy Conversion (Carbon Cycle 2.0)  

SciTech Connect

Ramamoorthy Ramesh from LBNL's Materials Science Division speaks at the Carbon Cycle 2.0 kick-off symposium Feb. 2, 2010. We emit more carbon into the atmosphere than natural processes are able to remove - an imbalance with negative consequences. Carbon Cycle 2.0 is a Berkeley Lab initiative to provide the science needed to restore this balance by integrating the Labs diverse research activities and delivering creative solutions toward a carbon-neutral energy future. http://carboncycle2.lbl.gov/

Ramesh, Ramamoorthy

2010-02-04

459

New energy conversion techniques in space, applicable to propulsion  

NASA Technical Reports Server (NTRS)

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.

Hertzberg, A.; Sun, K. C.

1989-01-01

460

Oscillation mode conversion and energy confinement of acoustically agitated bubbles.  

PubMed

The acoustically agitated bubble oscillation in liquids that is considered to be related to the half-subharmonic acoustic bubble oscillations is discussed in terms of parametric decay instability. At the frequency of about 40 kHz, the half-subharmonic bubble oscillation mode should be a surface bubble oscillation that does not easily emit acoustic waves into water and confines acoustic energy from longitudinal waves. The half-subharmonic bubble oscillation is the dominant mode that leads to parametric decay instability of bubble oscillations. PMID:12006008

Sato, Masanori; Shibuya, Nobunaga; Okada, Nagaya; Tou, Tonshaku; Fujii, Toshitaka

2002-04-01