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1

Solar energy thermally powered electrical generating system  

NASA Technical Reports Server (NTRS)

A thermally powered electrical generating system for use in a space vehicle is disclosed. The rate of storage in a thermal energy storage medium is controlled by varying the rate of generation and dissipation of electrical energy in a thermally powered electrical generating system which is powered from heat stored in the thermal energy storage medium without exceeding a maximum quantity of heat. A control system (10) varies the rate at which electrical energy is generated by the electrical generating system and the rate at which electrical energy is consumed by a variable parasitic electrical load to cause storage of an amount of thermal energy in the thermal energy storage system at the end of a period of insolation which is sufficient to satisfy the scheduled demand for electrical power to be generated during the next period of eclipse. The control system is based upon Kalman filter theory.

Owens, William R. (Inventor)

1989-01-01

2

MultiUse solar thermal power generators  

NASA Astrophysics Data System (ADS)

This paper describes Ontario Engineering International, Inc. (OEI) approach to a solar thermal power generation system using a number of thermal power generation technologies for possible applications to Mars exploration, material processing and for power generation on Earth. The latest power stage and generator design presented here were the culmination of studies covering a wide variety of generator configurations and operating parameters. The many steps and rationale leading to OEI's design evolution and materials selection will not be repeated here except for a description of OEI's latest design, including a heat source support scheme and power stage configuration. OEI's performance predictions were based on its techniques for the thermal analyses of thermal power generators. The analytical results indicate that the OEI power system design, operating within the stipulated solar input and temperature limits and well within its mass goals, can yield power outputs and system efficiencies that substantially exceed existing solar power generation technologies. The calculated efficiency for a cascaded power generation system is estimated to be 42% for a DC output or 37% for an AC power output. With the addition of a thermal storage medium power can be provided on a continuous basis during any shadow period. Recent advances in thermal power generation technologies have now progressed to the point where a solar thermal power generation system can be fabricated. This system can provide terrestrial power generation capacity in remote areas and provide a means for load leveling in the commercial power grid. This system is also adaptable for material processing and/or life-support on Mars. .

Abbott, Russell

2001-02-01

3

Solar Thermal Power Generation, 1978; Solar Thermal Heating and Cooling, 1978; Solar Thermal Components, 1978.  

National Technical Information Service (NTIS)

This bibliographic series cites and abstracts the literature and technical papers on electrical power generation primarily through solar thermal processes, the heating and cooling of buildings with solar thermal energy, and components applied to solar the...

1978-01-01

4

Automatic generation control in hydro-thermal electric power system  

Microsoft Academic Search

This paper deals with some aspects of automatic generation control of a two-area mixed hydro-thermal electric power system. The linear discrete time state space model with a thermal unit and a hydro unit per area, is used. The speed governor deadband and the generator rate constraints are being taken into consideration. Automatic Generation Control (AGC) of hydro units equipped with

Dido Derviševic

5

Thermal energy storage for power generation  

SciTech Connect

Studies strongly indicate that the United States will face widespread electrical power constraints in the 1990s, with most regions of the country experiencing capacity shortages by the year 2000. In many cases, the demand for increased power will occur during intermediate and peak demand periods. Much of this demand is expected to be met by oil- and natural gas-fired Brayton cycle turbines and combined-cycle plants. While natural gas is currently plentiful and reasonably priced, the availability of an economical long-term coal-fired option for peak and intermediate load power generation will give electric power utilities an option in case either the availability or cost of natural gas should deteriorate. 54 refs., 5 figs., 17 tabs.

Drost, M.K.; Antoniak, Z.I.; Brown, D.R.; Sathyanarayana, K.

1989-10-01

6

Device for thermal transfer and power generation  

DOEpatents

A system is provided. The system includes a device that includes top and bottom thermally conductive substrates positioned opposite to one another, wherein a top surface of the bottom thermally conductive substrate is substantially atomically flat and a thermal blocking layer disposed between the top and bottom thermally conductive substrates. The device also includes top and bottom electrodes separated from one another between the top and bottom thermally conductive substrates to define a tunneling path, wherein the top electrode is disposed on the thermal blocking layer and the bottom electrode is disposed on the bottom thermally conductive substrate.

Weaver, Stanton Earl (Northville, NY); Arik, Mehmet (Niskayuna, NY)

2011-04-19

7

Thermal analysis of thermoelectric power generator; Including thermal stresses  

NASA Astrophysics Data System (ADS)

In recent years, the energy demand is increasing leads to use and utilization of clean energy becomes target of countries all over the world. Thermoelectric generator is one type of clean energy generators which is a solid-state device that converts heat energy into electrical energy through the Seebeck effect. With availability of, heat from different sources such as solar energy and waste energy from systems, thermoelectric research becomes important research topic and researchers investigates efficient means of generating electricity from thermoelectric generators. One of the important problems with a thermoelectric is development of high thermal stresses due to formation of temperature gradient across the thermoelectric generator. High thermal stress causes device failure through cracks or fractures and these short comings may reduce the efficiency or totally fail the device. In this thesis work, thermodynamic efficiency and thermal stresses developed in thermoelectric generator are analyzed numerically. The bismuth telluride (Bi2Te3) properties are used in simulation. Stress levels in thermoelectric device pins are computed for various pin geometric configurations. MASTER.

Al-Merbati, Abdulrahman Salman

8

Solar thermal power generation: the solar tower, progress toward commercialization  

Microsoft Academic Search

In August of 1984 a utility assumed independent operation of Solar One. This ten Megawatt electric (MW\\/sub e\\/) solar powered thermal generating plant is now operated by Southern California Edison as an integrated part of its plant mix. During a three-year period, detailed records will be kept to determine operating cost, availability, capacity factor, reliability, performance, failure modes, degradation rates,

Vant-Hull

1985-01-01

9

Recent advances in direct solar thermal power generation  

Microsoft Academic Search

The recent energy crisis and environmental burden are becoming increasingly urgent and drawing enormous attention to solar-energy utilization. Direct solar thermal power generation technologies, such as thermoelectric, thermionic, magnetohydrodynamic, and alkali-metal thermoelectric methods, are among the most attractive ways to provide electric energy from solar heat. On the one hand, these methods have the potential to be more efficient than

Yue-Guang Deng; Jing Liu

2009-01-01

10

Advanced Stirling Radioisotope Generator (ASRG) Thermal Power Model in MATLAB  

NASA Technical Reports Server (NTRS)

This paper presents a one-dimensional steady-state mathematical thermal power model of the ASRG. It aims to provide a guideline of understanding how the ASRG works and what can change its performance. The thermal dynamics and energy balance of the generator is explained using the thermal circuit of the ASRG. The Stirling convertor performance map is used to represent the convertor. How the convertor performance map is coupled in the thermal circuit is explained. The ASRG performance characteristics under i) different sink temperatures and ii) over the years of mission (YOM) are predicted using the one-dimensional model. Two Stirling converter control strategies, i) fixing the hot-end of temperature of the convertor by adjusting piston amplitude and ii) fixing the piston amplitude, were tested in the model. Numerical results show that the first control strategy can result in a higher system efficiency than the second control strategy when the ambient gets warmer or the general-purpose heat source (GPHS) fuel load decays over the YOM. The ASRG performance data presented in this paper doesn't pertain to the ASRG flight unit. Some data of the ASRG engineering unit (EU) and flight unit that are available in public domain are used in this paper for the purpose of numerical studies.

Wang, Xiao-Yen, J.

2012-01-01

11

Advanced Stirling Radioisotope Generator Thermal Power Model in Thermal Desktop SINDA/FLUINT Analyzer  

NASA Technical Reports Server (NTRS)

This paper presents a three-dimensional Advanced Stirling Radioisotope Generator (ASRG) thermal power model that was built using the Thermal Desktop SINDA/FLUINT thermal analyzer. The model was correlated with ASRG engineering unit (EU) test data and ASRG flight unit predictions from Lockheed Martin's Ideas TMG thermal model. ASRG performance under (1) ASC hot-end temperatures, (2) ambient temperatures, and (3) years of mission for the general purpose heat source fuel decay was predicted using this model for the flight unit. The results were compared with those reported by Lockheed Martin and showed good agreement. In addition, the model was used to study the performance of the ASRG flight unit for operations on the ground and on the surface of Titan, and the concept of using gold film to reduce thermal loss through insulation was investigated.

Wang, Xiao-Yen; Fabanich, William A.; Schmitz, Paul C.

2012-01-01

12

Latent heat thermal storage for solar dynamic power generation  

SciTech Connect

Latent heat thermal storage is very attractive for space-based solar dynamic power systems. In this article, we describe a solar receiver unit (SRU) integrated with a phase change thermal storage facility. A two-dimensional model has been set up to simulate the transient behavior of the system. The resulting equations have been solved numerically by the finite difference method, and a parametric study on the performances of the SRU has been conducted; the results are presented and discussed.

Bellecci, C. (Universita della Calabria, Rende (Italy)); Conti, M. (Universita di Camerino (Italy))

1993-09-01

13

On-site solar-thermal electric power generation  

SciTech Connect

Some aspects of using on-site solar power generation for buildings are studied, particularly in relation to Rankine/vapor compression cooling. On the basis of the results of the various studies, computer models, and project reports examined, one is led to the conclusion that for on-site power generation systems interfaced with electric utilities, dedicated storage is not required, and in most instances would not be cost-effective. For solar Rankine cooling systems, in particular, the inclusion of a power generation capability interfaced with an electric utility could improve the cost effectiveness of such systems, by reducing the first cost through elimination of storage, and by increasing the solar collector utilization factor. Computer studies of various system configurations and penetration levels in various utility service areas are recommended, followed by experimental testing of the most promising systems identified by such studies.

Curran, H.M.

1981-05-01

14

Comparative performance of solar thermal power generation concepts  

NASA Technical Reports Server (NTRS)

A performance comparison is made between the central receiver system (power tower) and a distributed system using either dishes or troughs and lines to transport fluids to the power station. These systems were analyzed at a rated capacity of 30 MW of thermal energy delivered in the form of superheated steam at 538 C (1000 F) and 68 atm (1000 psia), using consistent weather data, collector surface waviness, pointing error, and electric conversion efficiency. The comparisons include technical considerations for component requirements, land utilization, and annual thermal energy collection rates. The relative merits of different representative systems are dependent upon the overall conversion as expressed in the form of performance factors in this paper. These factors are essentially indices of the relative performance effectiveness for different concepts based upon unit collector area. These performance factors enable further economic tradeoff studies of systems to be made by comparing them with projected production costs for these systems.

Wen, L.; Wu, Y. C.

1976-01-01

15

Modeling of dish-Stirling solar thermal power generation  

Microsoft Academic Search

Dish-Stirling solar power generation has emerged as an efficient and reliable source of renewable energy. As the technology moves into commercialization, models become necessary to predict system behavior under various operating conditions. Current literature on dish-Stirling modeling is scattered, focusing on individual components within the system. This paper establishes a background of the individual component models, and provides a method

Dustin Howard; Ronald G. Harley

2010-01-01

16

Low-cost distributed solar-thermal-electric power generation  

NASA Astrophysics Data System (ADS)

Due to their high relative cost, solar electric energy systems have yet to be exploited on a widespread basis. It is believed in the energy community that a technology similar to photovoltaic (PV), but offered at about $1/W would lead to widespread deployment at residential and commercial sites. This paper addresses the investigation and feasibility study of a low-cost solar thermal electricity generation technology, suitable for distributed deployment. Specifically, we discuss a system based on nonimaging solar concentrators, integrated with free-piston Stirling engine devices incorporating integrated electric generation. We target concentrator-collector operation at moderate temperatures, in the range of 125°C to 150°C. This temperature is consistent with use of optical concentrators with concentration ratios on the order of 1-2. These low ratio concentrators admit wide angles of radiation acceptance and are thus compatible with no diurnal tracking, and no or only a few seasonal adjustments. Thus, costs and reliability hazards associated with tracking hardware systems are avoided. Further, we note that in the intended application, there is no shortage of incident solar energy, but rather it is the capital cost of the solar-electric system that is most precious. Thus, we outline a strategy for exploiting solar resources in a cost constrained manner. The paper outlines design issues, and a specific design for an appropriately dimensioned free-piston Stirling engine. Only standard low-cost materials and manufacturing methods are required to realize such a machine.

Der Minassians, Artin; Aschenbach, Konrad H.; Sanders, Seth R.

2004-01-01

17

Thermal optimization of second harmonic generation at high pump powers.  

PubMed

We measure the temperature distribution of a 3 cm long periodically poled LiNbO? crystal in a single-pass second harmonic generation (SHG) setup at 488 nm. By means of three resistance heaters and directly mounted Pt100 sensors the crystal is subdivided in three sections. 9.4 W infrared pump light and 1.3 W of SHG light cause a de-homogenized temperature distribution of 0.2 K between the middle and back section. A sectional offset heating is used to homogenize the temperature in those two sections and thus increasing the conversion efficiency. A 15% higher SHG output power matching the prediction of our theoretical model is achieved. PMID:22109182

Sahm, Alexander; Uebernickel, Mirko; Paschke, Katrin; Erbert, Götz; Tränkle, Günther

2011-11-01

18

A Layered Matrix Cascade Genetic Algorithm and Particle Swarm Optimization Approach to Thermal Power Generation Scheduling  

Microsoft Academic Search

A layered matrix encoding cascade genetic algorithm and particle swarm optimization approach (GA-PSO) for unit commitment\\u000a and economic load dispatch problem in a thermal power system is presented in this paper. The tasks of determining and allocating\\u000a power generation to different thermal units in a way that the total power production cost is at the minimum subject to equality\\u000a and

Siew Chin Neoh; Norhashimah Morad; Chee Peng Lim; Zalina Abdul Aziz

19

Analytical investigation of thermal barrier coatings on advanced power generation gas turbines  

NASA Technical Reports Server (NTRS)

An analytical investigation of present and advanced gas turbine power generation cycles incorporating thermal barrier turbine component coatings was performed. Approximately 50 parametric points considering simple, recuperated, and combined cycles (including gasification) with gas turbine inlet temperatures from current levels through 1644K (2500 F) were evaluated. The results indicated that thermal barriers would be an attractive means to improve performance and reduce cost of electricity for these cycles. A recommended thermal barrier development program has been defined.

Amos, D. J.

1977-01-01

20

Technical and economical evaluation of solar thermal power generation  

Microsoft Academic Search

This article presents a feasibilty on a solar power system based on the Stirling dish (SD) technology, reviews and compares the available Stirling engines in the perspective of a solar Stirling system.The system is evaluated, as a parameter to alleviate the energy system of the Cretan island while taking care of the CO2 emissions. In the results a sensitivity analysis

Theocharis Tsoutsos; Vasilis Gekas; Katerina Marketaki

2003-01-01

21

A NOVEL SOLAR THERMAL COMBINED CYCLE FOR DISTRIBUTED POWER GENERATION  

EPA Science Inventory

Impacts of this work will be seen in the areas of energy, poverty alleviation, improvement of quality of health care provision and quality of life, business development, and education. We will be directly preventing installation of polluting diesel generators while improving ...

22

Research and development on a distributed type solar thermal power generation plant  

SciTech Connect

The 1973 energy crisis was the impetus for the Sunshine Project of the Japanese Ministry of International Trade and Industry (MITI) which is exploring new energy resources such as solar, coal, geothermal and hydrogen energies. The development of a solar thermal power generation system (STPS), an on-going project begun in 1974, has reached the point of completing two pilot plants at Nio, Kagawa, Japan. This paper describes the research and developmental work on a distributed type system, the plane-parabolic type solar thermal power generation system, and pilot plant operating experience.

Sumida, I.; Sakamoto, T.; Sato, S.; Taki, T.; Tsukamoto, M.

1983-10-01

23

NEAR-FIELD RADIATIVE TRANSFER: THERMAL RADIATION, THERMOPHOTOVOLTAIC POWER GENERATION AND OPTICAL CHARACTERIZATION  

Microsoft Academic Search

This dissertation focuses on near-field radiative transfer, which can be defined as the discipline concerned with energy transfer via electromagnetic waves at sub-wavelength distances. Three specific subjects related to this discipline are investigated, namely nearfield thermal radiation, nanoscale-gap thermophotovoltaic (nano-TPV) power generation and optical characterization. An algorithm for the solution of near-field thermal radiation problems in one-dimensional layered media is

Mathieu Francoeur

2010-01-01

24

Thermal and chemical tests of the steam generator of unit 3 at the Kalinin nuclear power station  

NASA Astrophysics Data System (ADS)

The results obtained from combined thermal and chemical tests of the steam generator of Unit 3 at the Kalinin nuclear power station are summarized. The obtained data are compared with the results of thermal and chemical tests carried out on steam generators at other nuclear power stations equipped with VVER-1000 reactors, and recommendations on selecting the steam-generator blowdown schedule are given.

Davidenko, N. N.; Trunov, N. B.; Saakov, E. S.; Berezanin, A. A.; Bogomolov, I. N.; Derii, V. P.; Nemytov, D. S.; Usanov, D. A.; Shestakov, N. B.; Shchelik, S. V.

2007-12-01

25

Thermal cycle efficiency of the indirect combined HTGR-GT power generation system.  

National Technical Information Service (NTIS)

High thermal efficiency of 50% could be expected in a power generation system coupling a high temperature gas-cooled reactor(HTGR) with a closed cycle gas turbine(GT). There are three candidate systems such as a direct cycle(DC), an indirect cycle(ICD) an...

Y. Muto

1996-01-01

26

Lessons Learned From the Generator Loss of Field at a Cogeneration Thermal Power Plant in Taiwan  

Microsoft Academic Search

Thecontribution of thispaperisthat we presentexpe- riences from dealing with practical issues related to synchronous machine stability events. We describe and analyze the scenarios of generator loss-of-field occurring two times at a cogeneration thermal power plant in Taiwan in the years 2003 and 2005. Since the total production loss from both events was quite large, some improvements have been implemented to

Chien-Hsing Lee; Ling-Shen Ma; Ching-Hsiang Weng; Bin-Kwie Chen

2011-01-01

27

A Feasibility Study of Solar Thermal Power Generation as the Pumping Power Source for Pumped Storage in Indonesia  

NASA Astrophysics Data System (ADS)

A pumped storage hydroelectric generation (PSHG) has been studied as alternative peak power source of the oil-fired power generation in Indonesia. However, because there is no surplus base load electricity even in the night, the economic advantage can not be found. The possibility of solar thermal power generation (STPG) is investigated to restrain the increase of fuel consumption by the existing peak power source. The optimum system simulation and the analysis of economy and environmental impact by a multiobjective optimization method provide the following results. The optimum aperture area and thermal storage capacity of STPG are found by the simulation based on the climate and the solar condition in West Java. PSHG with STPG as the power source of storage pump shows lower generation cost and CO2 emission than PSHG with existing oil fired peak power sources. Even if the fuel switch from oil to gas is supposed in future, PSHG with STPG will achieve the lower generation cost and CO2 emission than PSHG with the oil/gas fired combined cycle by sharing the peak electricity supply with the oil/gas fired combined cycle in an appropriate ratio. Furthermore, if the crude oil price hike in future is considered, PSHG with STPG may be the optimal solution for the peak electricity supply of Java-Bari grid.

Funatsu, Tetsuya; Natsume, Hiroaki

28

Apparatus for nuclear transmutation and power production using an intense accelerator-generated thermal neutron flux  

DOEpatents

Apparatus for nuclear transmutation and power production using an intense accelerator-generated thermal neutron flux. High thermal neutron fluxes generated from the action of a high power proton accelerator on a spallation target allows the efficient burn-up of higher actinide nuclear waste by a two-step process. Additionally, rapid burn-up of fission product waste for nuclides having small thermal neutron cross sections, and the practicality of small material inventories while achieving significant throughput derive from employment of such high fluxes. Several nuclear technology problems are addressed including 1. nuclear energy production without a waste stream requiring storage on a geological timescale, 2. the burn-up of defense and commercial nuclear waste, and 3. the production of defense nuclear material. The apparatus includes an accelerator, a target for neutron production surrounded by a blanket region for transmutation, a turbine for electric power production, and a chemical processing facility. In all applications, the accelerator power may be generated internally from fission and the waste produced thereby is transmuted internally so that waste management might not be required beyond the human lifespan.

Bowman, C.D.

1992-11-03

29

Apparatus for nuclear transmutation and power production using an intense accelerator-generated thermal neutron flux  

DOEpatents

Apparatus for nuclear transmutation and power production using an intense accelerator-generated thermal neutron flux. High thermal neutron fluxes generated from the action of a high power proton accelerator on a spallation target allows the efficient burn-up of higher actinide nuclear waste by a two-step process. Additionally, rapid burn-up of fission product waste for nuclides having small thermal neutron cross sections, and the practicality of small material inventories while achieving significant throughput derive from employment of such high fluxes. Several nuclear technology problems are addressed including 1. nuclear energy production without a waste stream requiring storage on a geological timescale, 2. the burn-up of defense and commercial nuclear waste, and 3. the production of defense nuclear material. The apparatus includes an accelerator, a target for neutron production surrounded by a blanket region for transmutation, a turbine for electric power production, and a chemical processing facility. In all applications, the accelerator power may be generated internally from fission and the waste produced thereby is transmuted internally so that waste management might not be required beyond the human lifespan.

Bowman, Charles D. (Los Alamos, NM)

1992-01-01

30

Thermal behavior of a high power generator exciter bridge measured by optical fiber sensors  

NASA Astrophysics Data System (ADS)

This paper presents temperature measurements taken at a 3-phase thyristor rectifier bridge in a synchronous generator using fiber Bragg grating (FBG) sensors applied directly on the thyristors upper surface. The results show the thermal behavior of the thyristors during the generator's start-up-phase and the period of time after the synchronization, with regulating operations as reaction to different load conditions. The temperature analysis is supported by current, voltage and power values of the hydroelectric power plant monitoring system. The trend of curves describes the typical behavior of thyristors which is proven with a four term transient thermal model. The different heat effect a thyristor experiences inside the switching-cabinet are also discussed.

Probst, Werner K.; Bortolotti, Fernando; de Morais Sousa, Kleiton; Kalinowski, Hypolito José; Martelli, Cicero; Cardozo da Silva, Jean Carlos

2013-05-01

31

A three-dimensional photonic-crystal emitter for thermal photovoltaic power generation.  

SciTech Connect

A three-dimensional tungsten photonic crystal is experimentally realized with a complete photonic band gap at wavelengths {lambda} {ge} 3 {micro}m. At an effective temperature of {approx} 1535 K, the photonic crystal exhibits a sharp emission at {approx}1.5 {micro}m and is promising for thermal photovoltaic (TPV) power generation. Based on the spectral radiance, a proper length scaling and a planar TPV model calculation, an optical-to-electric conversion efficiency of {approx}34% and electrical power of {approx}14 W/cm{sup 2} is theoretically possible.

Fleming, James Grant; Lin, Shawn-Yu; Moreno, James B.

2003-03-01

32

Power generation costs and ultimate thermal hydraulic power limits in hypothetical advanced designs with natural circulation  

SciTech Connect

Maximum power limits for hypothetical designs of natural circulation plants can be described analytically. The thermal hydraulic design parameters are those which limit the flow, being the elevations, flow areas, and loss coefficients. WE have found some simple ``design`` equations for natural circulation flow to power ratio, and for the stability limit. The analysis of historical and available data for maximum capacity factor estimation shows 80% to be reasonable and achievable. The least cost is obtained by optimizing both hypothetical plant performance for a given output,a nd the plant layout and design. There is also scope to increase output and reduce cost by considering design variations of primary and secondary pressure, and by optimizing component elevations and loss coefficients. The design limits for each are set by stability and maximum flow considerations, which deserve close and careful evaluation.

Duffey, R.B.; Rohatgi, U.S.

1996-12-31

33

Consideration of Thermoelectric Power Generation by Using Hot Spring Thermal Energy or Industrial Waste Heat  

NASA Astrophysics Data System (ADS)

Today, we face some significant environmental and energy problems such as global warming, urban heat island, and the precarious balance of world oil supply and demand. However, we have not yet found a satisfactory solution to these problems. Waste heat recovery is considered to be one of the best solutions because it can improve energy efficiency by converting heat exhausted from plants and machinery to electric power. This technology would also prevent atmospheric temperature increases caused by waste heat, and decrease fossil fuel consumption by recovering heat energy, thus also reducing CO2 emissions. The system proposed in this research generates electric power by providing waste heat or unharnessed thermal energy to built-in thermoelectric modules that can convert heat into electric power. Waste heat can be recovered from many places, including machinery in industrial plants, piping in electric power plants, waste incineration plants, and so on. Some natural heat sources such as hot springs and solar heat can also be used for this thermoelectric generation system. The generated power is expected to be supplied to auxiliary machinery around the heat source, stored as an emergency power supply, and so on. The attributes of this system are (1) direct power generation using hot springs or waste heat; (2) 24-h stable power generation; (3) stand-alone power system with no noise and no vibration; and (4) easy maintenance attributed to its simple structure with no moving parts. In order to maximize energy use efficiency, the temperature difference between both sides of the thermoelectric (TE) modules built into the system need to be kept as large as possible. This means it is important to reduce thermal resistance between TE modules and heat source. Moreover, the system's efficiency greatly depends on the base temperature of the heat sources and the material of the system's TE modules. Therefore, in order to make this system practical and efficient, it is necessary to choose the heat source first and then design the most appropriate structure for the source by applying analytical methods. This report describes how to design a prototype of a thermoelectric power generator using the analytical approach and the results of performance evaluation tests carried out in the field.

Sasaki, Keiichi; Horikawa, Daisuke; Goto, Koichi

2014-05-01

34

Near-field radiative transfer: Thermal radiation, thermophotovoltaic power generation and optical characterization  

NASA Astrophysics Data System (ADS)

This dissertation focuses on near-field radiative transfer, which can be defined as the discipline concerned with energy transfer via electromagnetic waves at sub-wavelength distances. Three specific subjects related to this discipline are investigated, namely near-field thermal radiation, nanoscale-gap thermophotovoltaic (nano-TPV) power generation and optical characterization. An algorithm for the solution of near-field thermal radiation problems in one-dimensional layered media is developed, and several tests are performed showing the accuracy, consistency and versatility of the procedure. The possibility of tuning near-field radiative heat transfer via thin films supporting surface phonon-polaritons (SPhPs) in the infrared is afterwards investigated via the computation of the local density of electromagnetic states and the radiative heat flux between two films. Results reveal that due to SPhP coupling, fine tuning of near-field radiative heat transfer is possible by solely varying the structure of the system, the structure being the film thicknesses and their distance of separation. The coexistence of two regimes of near-field thermal radiation between two thin films of silicon carbide is demonstrated via numerical simulations and an asymptotic analysis of the radiative heat transfer coefficient. The impacts of thermal effects on the performances of nano-TPV power generators are investigated via the solution of the coupled near-field thermal radiation, charge and heat transport problem. The viability of nano-TPV devices proposed so far in the literature, based on a tungsten radiator at 2000 K and indium gallium antimonide cell, is questioned due to excessive heating of the junction converting thermal radiation into electricity. Using a convective thermal management system, a heat transfer coefficient as high as 105 Wm-2K-1 is required to maintain the junction at room temperature. The possibility of characterizing non-intrusively, and potentially in real-time, nanoparticles from 5 nm to 100 nm in size via scattered surface wave is explored. The feasibility of the characterization framework is theoretically demonstrated via a sensitivity analysis of the scattering matrix elements. Measurements of the scattering matrix elements for 200 nm and 50 nm gold spherical particles show the great sensitivity of the characterization tool, although an ultimate calibration is difficult with the current version of the experimental set-up. KEYWORDS: Near-field thermal radiation, Surface phonon-polariton, Nanoscale-gap thermophotoltaic power generation, Optical characterization of nanoparticles, Scattering (Mueller) matrix

Francoeur, Mathieu

35

Performance of a direct steam generation solar thermal power plant for electricity production as a function of the solar multiple  

Microsoft Academic Search

This paper describes the influence of the solar multiple on the annual performance of parabolic trough solar thermal power plants with direct steam generation (DSG). The reference system selected is a 50MWe DSG power plant, with thermal storage and auxiliary natural gas-fired boiler. It is considered that both systems are necessary for an optimum coupling to the electricity grid. Although

M. J. Montes; A. Abánades; J. M. Martínez-Val

2009-01-01

36

Integrating planning and design optimization for thermal power generation in developing economies: Designs for Vietnam  

NASA Astrophysics Data System (ADS)

In the twenty first century, global warming and climate change have become environmental issues worldwide. There is a need to reduce greenhouse gas emissions from thermal power plants through improved efficiency. This need is shared by both developed and developing countries. It is particularly important in rapidly developing economies (for example, Vietnam, South Korea, and China) where there is very significant need to increase generation capacity. This thesis addresses improving thermal power plant efficiency through an improved planning process that emphasizes integrated design. With the integration of planning and design considerations of key components in thermal electrical generation, along with the selection of appropriate up-to-date technologies, greater efficiency and reduction of emissions could be achieved. The major barriers to the integration of overall power plant optimization are the practice of individual island tendering packages, and the lack of coordinating efforts between major original equipment manufacturers (OEM). This thesis assesses both operational and design aspects of thermal power plants to identify opportunities for energy saving and the associated reduction of CO2 emissions. To demonstrate the potential of the integrated planning design approach, three advanced thermal power plants, using anthracite coal, oil and gas as their respective fuel, were developed as a case study. The three plant formulations and simulations were performed with the cooperation of several leading companies in the power industry including Babcock & Wilcox, Siemens KWU, Siemens-Westinghouse Power Corporation, Hitachi, Alstom Air Preheater, TLT-Covent, and ABB Flakt. The first plant is a conventional W-Flame anthracite coal-fired unit for base load operation. The second is a supercritical oil-fired plant with advanced steam condition, for two shifting and cycling operations. The third plant is a gas-fired combined cycle unit employing a modern steam-cooled gas turbine and a three-pressure heat recovery steam generator with reheat, for base load and load following operations. The oil-fired and gas-fired plants showed excellent gross thermal efficiency, 49.6 and 59.4 percent, respectively. Regarding the anthracite plant, based on a traditional subcritical pressure steam cycle, the unit gross efficiency was calculated at 42.3 percent. These efficiency values represent an increase of over 2 percent compared to the comparable plant class, operating today. This 2 percent efficiency gained translates into approximately 35,000 tonnes of greenhouse gas reduction, and a saving of 16,000 tonnes of coal, per year (based on 300MWe coal-fired plant). The positive results from the three simulations have demonstrated that by integrating planning and design optimization, significant gain of efficiency in thermal power plants is possible. This establishes the need for improved planning processes. It starts with a pre-planning process, before project tendering, to identify applicable operational issues and design features to enhance efficiency and reduce emissions. It should also include a pre-contract period to provide an opportunity for all OEM finalists to consolidate and fine-tune their designs for compatibility with those of others to achieve optimal performance. The inclusion of a period for final consolidation and integrated design enables the original goals of greater overall plant efficiency and greenhouse gas emissions reduction to be achieved beyond those available from current planning and contracting procedures.

Pham, John Dinh Chuong

37

History and Current Status of Generation 3 Thermal Sleeves in Westinghouse Nuclear Power Plants.  

National Technical Information Service (NTIS)

From mid-1982 until 1987, loose thermal sleeves or sleeves with cracked attachment welds were found in several operating Westinghouse nuclear power plants. Westinghouse investigations concluded that these occurences had been confined to those thermal slee...

G. Martin

1992-01-01

38

Thermally cascaded thermoelectric generator  

NASA Technical Reports Server (NTRS)

High efficiency thermoelectric generator utilizes a high-temperature thermoelectric material in thermal series with a low-temperature material. A thermally cascaded generator increases system efficiency.

Flaherty, R.

1970-01-01

39

Metal Hydride Thermal Storage: Reversible Metal Hydride Thermal Storage for High-Temperature Power Generation Systems  

SciTech Connect

HEATS Project: PNNL is developing a thermal energy storage system based on a Reversible Metal Hydride Thermochemical (RMHT) system, which uses metal hydride as a heat storage material. Heat storage materials are critical to the energy storage process. In solar thermal storage systems, heat can be stored in these materials during the day and released at night—when the sun is not out—to drive a turbine and produce electricity. In nuclear storage systems, heat can be stored in these materials at night and released to produce electricity during daytime peak-demand hours. PNNL’s metal hydride material can reversibly store heat as hydrogen cycles in and out of the material. In a RHMT system, metal hydrides remain stable in high temperatures (600- 800°C). A high-temperature tank in PNNL’s storage system releases heat as hydrogen is absorbed, and a low-temperature tank stores the heat until it is needed. The low-cost material and simplicity of PNNL’s thermal energy storage system is expected to keep costs down. The system has the potential to significantly increase energy density.

None

2011-12-05

40

Thermal energy storage: Basics, design, applications to power generation and heat supply  

SciTech Connect

This book discusses the history of thermal energy storage, storage of sensible heat in saturated fluids and in solids, and storage in gas turbine power plants. The author provides chapter bibliographies.

Beckmann, G.; Gilli, P.V.

1984-01-01

41

Summary assessment of solar thermal parabolic dish technology for electrical power generation  

NASA Technical Reports Server (NTRS)

An assessment is provided of solar thermal parabolic dish technology for electrical power generation. The assessment is based on the development program undertaken by the Jet Propulsion Laboratory for the U.S. Department of Energy and covers the period from the initiation of the program in 1976 through mid-1984. The program was founded on developing components and subsystems that are integrated into parabolic dish power modules for test and evaluation. The status of the project is summarized in terms of results obtained through testing of modules, and the implications of these findings are assessed in terms of techno-economic projections and market potential. The techno-economic projections are based on continuation of an evolutionary technological development program and are related to the accomplishments of the program as of mid-1984. The accomplishments of the development effort are summarized for each major subsystem including concentrators, receivers, and engines. The ramifications of these accomplishments are assessed in the context of developmental objectives and strategies.

Penda, P. L.; Fujita, T.; Lucas, J. W.

1985-01-01

42

Technical concepts and economic prospects for thermal hydrogen power plants for peak load generation  

Microsoft Academic Search

Attention is given to hydrogen-oxygen steam generators and closed gas turbine processes with internal hydrogen-oxygen combustion, two techniques applicable to peak-load electrical generation. Costs of the electrolysis, the hydrogen and oxygen storage facilities, and the steam generators or gas turbine adaptations needed for the nitrogen-oxygen power plants are analyzed. In addition, advantages of the hydrogen-oxygen power plants, including the absence

W. Tanner

1977-01-01

43

Design and thermal analysis of a two stage solar concentrator for combined heat and thermoelectric power generation  

Microsoft Academic Search

A design procedure and thermal performance analysis of a two stage solar energy concentrator suited to combined heat and thermoelectric power generation are presented. The concentrator is comprised of a primary one axis parabolic trough concentrator and a second stage compound parabolic concentrator mounted at the focus of the primary. The thermoelectric device is attached to the absorber plate at

Siddig A. Omer; David G. Infield

2000-01-01

44

Efficient storage capacity in power systems with thermal and renewable generation  

Microsoft Academic Search

Power systems with high shares of wind and solar power have to balance their intermittent nature. Pumpedâ€hydro storage plants can provide the required flexibility, while thermal backup plants offer an alternative. This paper proposes a model based on peakâ€loadâ€pricing theory to describe the efficient technology portfolio. Drawing on a load duration curve, we derive the efficient storage capacity and discuss

Bjarne Steffen; Christoph Weber

2011-01-01

45

Integrating planning and design optimization for thermal power generation in developing economies: Designs for Vietnam  

Microsoft Academic Search

In the twenty first century, global warming and climate change have become environmental issues worldwide. There is a need to reduce greenhouse gas emissions from thermal power plants through improved efficiency. This need is shared by both developed and developing countries. It is particularly important in rapidly developing economies (for example, Vietnam, South Korea, and China) where there is very

John Dinh Chuong Pham

2005-01-01

46

Design of Nonlinear Frequency Controller for Isolated Thermal Power System with Generation Rate Constraint  

Microsoft Academic Search

A nonlinear control scheme for thermal power system frequency control is described. Nonlinear controller is developed through\\u000a describing function stability analysis of the system Controller ensures stability of the system for any input. Simulation\\u000a results are given showing the smooth operation of described control scheme. Paper describes in detail the stability analysis\\u000a and controller design.

Ognjen Kuljaca; Jyotirmay Gadewadikar; Kwabena Agyepong

2008-01-01

47

Solar thermal electricity generation  

NASA Astrophysics Data System (ADS)

This report presents the results of modeling the thermal performance and economic feasibility of large (utility scale) and small solar thermal power plants for electricity generation. A number of solar concepts for power systems applications have been investigated. Each concept has been analyzed over a range of plant power ratings from 1 MW(sub e) to 300 MW(sub e) and over a range of capacity factors from a no-storage case (capacity factor of about 0.25 to 0.30) up to intermediate load capacity factors in the range of 0.46 to 0.60. The solar plant's economic viability is investigated by examining the effect of various parameters on the plant costs (both capital and O & M) and the levelized energy costs (LEC). The cost components are reported in six categories: collectors, energy transport, energy storage, energy conversion, balance of plant, and indirect/contingency costs. Concentrator and receiver costs are included in the collector category. Thermal and electric energy transport costs are included in the energy transport category. Costs for the thermal or electric storage are included in the energy storage category; energy conversion costs are included in the energy conversion category. The balance of plant cost category comprises the structures, land, service facilities, power conditioning, instrumentation and controls, and spare part costs. The indirect/contingency category consists of the indirect construction and the contingency costs. The concepts included in the study are (1) molten salt cavity central receiver with salt storage (PFCR/R-C-Salt); (2) molten salt external central receiver with salt storage (PFCR/R-E-Salt); (3) sodium external central receiver with sodium storage (PFCR/RE-Na); (4) sodium external central receiver with salt storage (PFCR/R-E-Na/Salt); (5) water/steam external central receiver with oil/rock storage (PFCR/R-E-W/S); (6) parabolic dish with stirling engine conversion and lead acid battery storage (PFDR/SLAB); (7) parabolic dish with stirling engine conversion and redox advanced battery storage (PFDR/S-RAB); and (8) parabolic trough with oil/rock storage (LFDR/R-HT-45). Key annual efficiency and economic results of the study are highlighted in tabular format for plant sizes and capacity factor that resulted in the lowest LEC over the analysis range.

Gasemagha, Khairy Ramadan

1993-01-01

48

Next generation cooled long range thermal sights with minimum size, weight, and power  

NASA Astrophysics Data System (ADS)

Situational awareness and precise targeting at day, night and severe weather conditions are key elements for mission success in asymmetric warfare. To support these capabilities for the dismounted soldier, AIM has developed a family of stand-alone thermal weapon sights based on high performance cooled IR-modules which are used e.g. in the infantryman of the future program of the German army (IdZ). The design driver for these sights is a long ID range <1500m for the NATO standard target to cover the operational range of a platoon with the engagement range of .50 cal rifles, 40mm AGLs or for reconnaissance tasks. The most recent sight WBZG has just entered into serial production for the IdZ enhanced system of the German army with additional capabilities like a wireless data link to the soldier backbone computer. Minimum size, weight and power (SWaP) are most critical requirements for the dismounted soldiers' equipment and sometimes push a decision towards uncooled equipment with marginal performance referring to the outstanding challenges in current asymmetric warfare, e.g. the capability to distinguish between combatants and non-combatants in adequate ranges. To provide the uncompromised e/o performance with SWaP parameters close to uncooled, AIM has developed a new thermal weapon sight based on high operating temperature (HOT) MCT MWIR FPAs together with a new low power single piston stirling cooler. In basic operation the sight is used as a clip-on in front of the rifle scope. An additional eyepiece for stand-alone targeting with e.g. AGLs or a biocular version for relaxed surveillance will be available. The paper will present details of the technologies applied for such long range cooled sights with size, weight and power close to uncooled.

Breiter, R.; Ihle, T.; Wendler, J.; Rühlich, I.; Ziegler, J.

2013-06-01

49

Development of a phase-change thermal storage system using modified anhydrous sodium hydroxide for solar electric power generation  

NASA Technical Reports Server (NTRS)

A thermal storage system for use in solar power electricity generation was investigated analytically and experimentally. The thermal storage medium is principally anhydrous NaOH with 8% NaNO3 and 0.2% MnO2. Heat is charged into storage at 584 K and discharged from storage at 582 K by Therminol-66. Physical and thermophysical properties of the storage medium were measured. A mathematical simulation and computer program describing the operation of the system were developed. A 1/10 scale model of a system capable of storing and delivering 3.1 x 10 to the 6th power kJ of heat was designed, built, and tested. Tests included steady state charging, discharging, idling, and charge-discharge conditions simulating a solar daily cycle. Experimental data and computer-predicted results are correlated. A reference design including cost estimates of the full-size system was developed.

Cohen, B. M.; Rice, R. E.; Rowny, P. E.

1978-01-01

50

Development of a Thermal Buffering Device to Cope with Temperature Fluctuations for a Thermoelectric Power Generator  

NASA Astrophysics Data System (ADS)

To stabilize the heat input to a thermoelectric generator (TEG) and protect it from large temperature fluctuations, a thermal buffering device (TBD) was fabricated and examined using a typical Bi-Te TEG module and a brand-new Mg2Si TEG module. The TBD comprises two adjoining heat storage containers, each containing different alloys, which can be optimized for the temperature range of the TEG. The combination of two alloys in series diminishes the thermal fluctuations, stabilizing the heat input to the TEG module. This is achieved by having two metallic materials with large enthalpies of fusion that can be placed between the heat source and the TEG. The combination of the two alloys can be optimized for the temperature ranges of Bi-Te, Pb-Te, or Co-Sb. For the Bi-Te TEG, 15Al-85Zn and 30Sn-70Zn alloys were used for the heat source side and the TEG side, respectively. The corresponding alloys for the Mg2Si TEG were 20Ni-80Al and 7Si-93Al. With the use of a TBD, the Bi-Te TEG exhibited no notable damage even in the rather high temperature range beyond ˜573 K. For the Mg2Si TEG, no operational damage of the Mg2Si TEG module was observed even with a temperature of 1020 K.

Mizuno, Kuniaki; Sawada, Kazunori; Nemoto, Takashi; Iida, Tsutomu

2012-06-01

51

Thermal-powered reciprocating pump  

NASA Technical Reports Server (NTRS)

Waste heat from radioisotope thermal generators in spacecraft is transported to keep instruments warm by two-cylinder reciprocating pump powered by energy from warm heat exchange fluid. Each cylinder has thermally nonconductive piston, heat exchange coil, and heat sink surface.

Sabelman, E. E.

1972-01-01

52

Piezoelectric, solar and thermal energy harvesting for hybrid low-power generator systems with thin-film batteries  

NASA Astrophysics Data System (ADS)

The harvesting of ambient energy to power small electronic components has received tremendous attention over the last decade. The research goal in this field is to enable self-powered electronic components for use particularly in wireless sensing and measurement applications. Thermal energy due to temperature gradients, solar energy and ambient vibrations constitute some of the major sources of energy that can be harvested. Researchers have presented several papers focusing on each of these topics separately. This paper aims to develop a hybrid power generator and storage system using these three sources of energy in order to improve both structural multifunctionality and system-level robustness in energy harvesting. A multilayer structure with flexible solar, piezoceramic, thin-film battery and metallic substructure layers is developed (with the overhang dimensions of 93 mm × 25 mm × 1.5 mm in cantilevered configuration). Thermal energy is also used for charging the thin-film battery layers using a 30.5 mm × 33 mm × 4.1 mm generator. Performance results are presented for charging and discharging of the thin-film battery layers using each one of the harvesting methods. It is shown based on the extrapolation of a set of measurements that 1 mA h of a thin-film battery can be charged in 20 min using solar energy (for a solar irradiance level of 223 W m-2), in 40 min using thermal energy (for a temperature difference of 31 °C) and in 8 h using vibrational energy (for a harmonic base acceleration input of 0.5g at 56.4 Hz).

Gambier, P.; Anton, S. R.; Kong, N.; Erturk, A.; Inman, D. J.

2012-01-01

53

Examination of a Thermally Viable Structure for an Unconventional Uni-Leg Mg2Si Thermoelectric Power Generator  

NASA Astrophysics Data System (ADS)

We have fabricated an unconventional uni-leg structure thermoelectric generator (TEG) element using quad thermoelectric (TE) chips of Sb-doped n-Mg2Si, which were prepared by a plasma-activated sintering process. The power curve characteristics, the effect of aging up to 500 h, and the thermal gradients at several points on the module were investigated. The observed maximum output power with the heat source at 975 K and the heat sink at 345 K was 341 mW, from which the ? T for the TE chip was calculated to be about 333 K. In aging testing in air ambient, a remarkable feature of the results was that there was no notable change from the initial resistance of the TEG module for as long as 500 h. The thermal distribution for the fabricated uni-leg TEG element was analyzed by finite-element modeling using ANSYS software. To tune the calculation parameters of ANSYS, such as the thermal conductance properties of the corresponding coupled materials in the module, precise measurements of the temperature at various probe points on the module were made. Then, meticulous verification between the measured temperature values and the results calculated by ANSYS was carried out to optimize the parameters.

Sakamoto, Tatsuya; Iida, Tsutomu; Taguchi, Yutaka; Kurosaki, Shota; Hayatsu, Yusuke; Nishio, Keishi; Kogo, Yasuo; Takanashi, Yoshifumi

2012-06-01

54

Geothermal Power Generation  

SciTech Connect

The report provides an overview of the renewed market interest in using geothermal for power generation including a concise look at what's driving interest in geothermal power generation, the current status of geothermal power generation, and plans for the future. Topics covered in the report include: an overview of geothermal power generation including its history, the current market environment, and its future prospects; an analysis of the key business factors that are driving renewed interest in geothermal power generation; an analysis of the challenges that are hindering the implementation of geothermal power generation projects; a description of geothermal power generation technologies; a review of the economic drivers of geothermal power generation project success; profiles of the major geothermal power producing countries; and, profiles of the major geothermal power project developers.

NONE

2007-11-15

55

Daily Integrated Generation Scheduling for Thermal, Pumped-Storage Hydro and Cascaded Hydro Units and Purchasing Power Considering Network Constraints  

NASA Astrophysics Data System (ADS)

We have developed an innovative power generation scheduling method using quadratic programming (QP). The advantage of using our method is that it simultaneously solves unit commitment and economic load dispatch. We relax the binary variables of the unit state into continuous variables to apply QP to this problem. We also add the penalty term to converge the value of those variables to 0 or 1 to the objective function; the sum of fuel costs and start-up costs. This penalty term depends on per-unit fuel cost. The possibility of its variable converging to zero increases as the cost increases. This method was applied to a test system of daily generation scheduling that consisted of 29 thermal units, two pumped-storage units, four cascaded-hydro units, and one transmission. The schedule satisfied all constraints, i.e., load-power balance, operation reserve, power flow, minimum up/down-times, and fuel consumption. This result shows that the developed method is effective.

Sawa, Toshiyuki; Sato, Yasuo; Tsurugai, Mitsuo; Onishi, Tsukasa

56

Optimal Wind–Thermal Generating Unit Commitment  

Microsoft Academic Search

As wind power penetrations increase in isolated power systems, more innovative and sophisticated approaches to system operation will need to be adopted due to the intermittency and unpredictability of wind power generation. In this paper, a hybrid approach of combining branch and bound algorithm with a dynamic programming algorithm is developed to coordinate the wind and thermal generation scheduling problem

2008-01-01

57

Solar thermal electricity generation - EURELIOS, the 1 MW\\/el\\/ helioelectric power plant of the European communities  

Microsoft Academic Search

The different technologies of solar thermal power electricity conversion are discussed and the main power plants under construction or already in operation are listed.EURELIOS, the world's first experimental solar power plant in the megawatt range, the construction of which was completed by the end of 1980 and which feeds electricity into the grid of ENEL, the Italian National Electricity Board,

JOACHIM GRETZ

1982-01-01

58

MHD Power Generation  

ERIC Educational Resources Information Center

Explains the operation of the Magnetohydrodynamic (MHD) generator and advantages of the system over coal, oil or nuclear powered generators. Details the development of MHD generators in the United States and Soviet Union. (CP)

Kantrowitz, Arthur; Rosa, Richard J.

1975-01-01

59

Electromagnetic Vibration Power Generator  

Microsoft Academic Search

This paper shows an alternative for supplying wireless sensors with energy: electrical power is generated from an ambient mechanical vibration by use of a vibration power generator. As the generator is excited by ambient mechanical vibration, its construction produces a relative movement of a magnetic circuit. This movement induces a current into an electrical coil due to Faraday's law. For

Z. Hadas; M. Kluge; V. Singule; C. Ondrusek

2007-01-01

60

Environmental benefits of DGs and comparing their generation costs with thermal power plants considering production pollution on human health  

Microsoft Academic Search

The increase of DG presence in distribution network is the immediate result of technology development and power crisis in the world. Nowadays, using renewable energy sources and high efficiency electrical systems (Combined Heat and Power Generation) is increasing rapidly all over the world. However, exploitation systems and old managing in industry have lead to a misunderstanding of DG benefits. This,

M. Massaeli; S. A. M. Javadian; N. Khalesi

2011-01-01

61

JV Task 46 - Development and Testing of a Thermally Integrated SOFC-Gasification System for Biomass Power Generation.  

National Technical Information Service (NTIS)

The Energy & Environmental Research Center has designed a biomass power system using a solid oxide fuel cell (SOFC) thermally integrated with a downdraft gasifier. In this system, the high-temperature effluent from the SOFC enables the operation of a subs...

D. Singh K. E. Martin N. Patel P. N. Hutton

2008-01-01

62

Spectrophotovoltaic Orbital Power Generation.  

National Technical Information Service (NTIS)

The feasibilty of a spectrophotovoltaic orbital power generation system that optically concentrates solar energy is demonstrated. A dichroic beam-splitting mirror is used to divide the solar spectrum into two wavebands. Absorption of these wavebands by Ga...

J. R. Onffroy

1980-01-01

63

Electrical power generating system. [for windpowered generation  

NASA Technical Reports Server (NTRS)

An alternating current power generation system adopted to inject power in an already powered power line is discussed. The power generating system solves to adjustably coup an induction motor, as a generator, to an ac power line wherein the motor and power line are connected through a triac. The triac is regulated to normally turn on at a relatively late point in each half cycle of its operation, whereby at less than operating speed, and thus when the induction motor functions as a motor rather than as a generator, power consumption from the line is substantially reduced. The principal application will be for windmill powered generation.

Nola, F. J. (inventor)

1981-01-01

64

Thermal energy storage for direct steam generation  

Microsoft Academic Search

Parabolic trough power plants with direct steam generation are a promising option for future cost reduction in comparison to the SEGS type technology. These new solar thermal power plants require innovative storage concepts, where the two-phase heat transfer fluid poses a major challenge. A three-part storage system is proposed where a phase change material (PCM) storage will be deployed for

Doerte Laing; Carsten Bahl; Thomas Bauer; Dorothea Lehmann; Wolf-Dieter Steinmann

2011-01-01

65

A Power And Thermal System with Thermoelectric Generators At 930 C For Solar Probe Inside 0.1 AU  

NASA Technical Reports Server (NTRS)

The Power System for Solar Probe is required to provide an electrical power of 100 W to 200 W over a wide range of radial distances from the Sun. The distance varies from 5.2 AU (i.e., Jupiter gravity assist orbit) and 4 solar radii. The solar intensity varies by nearly 5 orders of magnitude. Radioactive Thermoelectric Generator (RTG) is one way to meet the power requirement. However, the use of an RTG presents a politically expensive risk for the mission. An alternative is a totally non-nuclear and intrinsically conservative method, which uses mostly developed technologies. This paper presents an innovative concept, which uses thermoelectric generators with a high temperature cooling system to meet the power requirement inside 0. 1 AU. In this concept, Silicon Germanium (SiGe)/Gallium Phosphorus (GaP) thermoelectric generators use the infrared radiation from the spacecraft primary heat shield as an energy source, and a liquid sodium high temperature cooling system to maintain the SiGe/GaP thermoelectric generators at 1200 K. It allows a routine access by interplanetary probes to the innermost regions of the heliosphere, which is prudent to the scientific community.

Choi, Michael K.; Powers, Edward I. (Technical Monitor)

2001-01-01

66

Use of biogas for cogeneration of heat and electricity for local application: performance evaluation of an engine power generator and a sludge thermal dryer.  

PubMed

A small unit of cogeneration of energy and heat was tested at the Centre for Research and Training on Sanitation UFMG/COPASA - CePTS, located at the Arrudas Sewage Treatment Plant, in Belo Horizonte, Minas Gerais, Brazil. The unit consisted of an engine power generator adapted to run on biogas, a thermal dryer prototype and other peripherals (compressor, biogas storage tank, air blower, etc.). The heat from engine power generator exhaust gases was directed towards the thermal dryer prototype to dry the sludge and disinfect it. The results showed that the experimental apparatus is self-sufficient in electricity, even producing a surplus, available for other uses. The tests of drying and disinfection of sludge lasted 7 h, leading to an increase in solids content from 4 to 8% (50% reduction in sludge volume). Although the drying of sludge was not possible (only thickening was achieved), the disinfection process proved very effective, enabling the complete inactivation of helminth eggs. PMID:23128634

Lobato, L C S; Chernicharo, C A L; Pujatti, F J P; Martins, O M; Melo, G C B; Recio, A A R

2013-01-01

67

Ocean thermal gradient hydraulic power plant.  

PubMed

Solar energy stored in the oceans may be used to generate power by exploiting ploiting thermal gradients. A proposed open-cycle system uses low-pressure steam to elevate vate water, which is then run through a hydraulic turbine to generate power. The device is analogous to an air lift pump. PMID:17813707

Beck, E J

1975-07-25

68

Assessment of generic solar thermal systems for large power applications: analysis of electric power generating costs for systems larger than 10 MWe  

SciTech Connect

Seven generic types of collectors, together with associated subsystems for electric power generation, were considered. The collectors can be classified into three categories: (1) two-axis tracking (with compound-curvature reflecting surfaces); (2) one-axis tracking (with single-curvature reflecting surfaces); and (3) nontracking (with low-concentration reflecting surfaces). All seven collectors were analyzed in conceptual system configurations with Rankine-cycle engines. In addition, two of the collectors were analyzed with Brayton-cycle engines, and one was analyzed with a Stirling-cycle engine. With these engine options, and the consideration of both thermal and electrical storage for the Brayton-cycle central receiver, 11 systems were formulated for analysis. Conceptual designs developed for the 11 systems were based on common assumptions of available technology in the 1990 to 2000 time frame. No attempt was made to perform a detailed optimization of each conceptual design. Rather, designs best suited for a comparative evaluation of the concepts were formulated. Costs were estimated on the basis of identical assumptions, ground rules, methodologies, and unit costs of materials and labor applied uniformly to all of the concepts. The computer code SOLSTEP was used to analyze the thermodynamic performance characteristics and energy costs of the 11 concepts. Year-long simulations were performed using meteorological and insolation data for Barstow, California. Results for each concept include levelized energy costs and capacity factors for various combinations of storage capacity and collector field size.

Apley, W.J.; Bird, S.P.; Brown, D.R.; Drost, M.K.; Fort, J.A.; Garrett-Price, B.A.; Patton, W.P.; Williams, T.A.

1980-11-01

69

Peak power ratio generator  

DOEpatents

A peak power ratio generator is described for measuring, in combination with a conventional power meter, the peak power level of extremely narrow pulses in the gigahertz radio frequency bands. The present invention in a preferred embodiment utilizes a tunnel diode and a back diode combination in a detector circuit as the only high speed elements. The high speed tunnel diode provides a bistable signal and serves as a memory device of the input pulses for the remaining, slower components. A hybrid digital and analog loop maintains the peak power level of a reference channel at a known amount. Thus, by measuring the average power levels of the reference signal and the source signal, the peak power level of the source signal can be determined.

Moyer, Robert D. (Albuquerque, NM)

1985-01-01

70

SOLAR THERMAL POWER PLANTS FOR HYDROGEN PRODUCTION  

Microsoft Academic Search

Renewable power plants are needed, if a high amount of hydrogen shall be produced for the use in a climate-compatible energy market. Since the potentials of hydro and wind power are limited, solar electricity generation will take over an important part in the near future. Solar thermal power plants in the Mediterranean area are one promising option. After a short

Volker Quaschning; Franz Trieb

2001-01-01

71

JV Task 46 - Development and Testing of a Thermally Integrated SOFC-Gasification System for Biomass Power Generation  

SciTech Connect

The Energy & Environmental Research Center has designed a biomass power system using a solid oxide fuel cell (SOFC) thermally integrated with a downdraft gasifier. In this system, the high-temperature effluent from the SOFC enables the operation of a substoichiometric air downdraft gasifier at an elevated temperature (1000 C). At this temperature, moisture in the biomass acts as an essential carbon-gasifying medium, reducing the equivalence ratio at which the gasifier can operate with complete carbon conversion. Calculations show gross conversion efficiencies up to 45% (higher heating value) for biomass moisture levels up to 40% (wt basis). Experimental work on a bench-scale gasifier demonstrated increased tar cracking within the gasifier and increased energy density of the resultant syngas. A series of experiments on wood chips demonstrated tar output in the range of 9.9 and 234 mg/m{sup 3}. Both button cells and a 100-watt stack was tested on syngas from the gasifier. Both achieved steady-state operation with a 22% and 15% drop in performance, respectively, relative to pure hydrogen. In addition, tar tolerance testing on button cells demonstrated an upper limit of tar tolerance of approximately 1%, well above the tar output of the gasifier. The predicted system efficiency was revised down to 33% gross and 27% net system efficiency because of the results of the gasifier and fuel cell experiments. These results demonstrate the feasibility and benefits of thermally integrating a gasifier and a high-temperature fuel cell in small distributed power systems.

Phillip Hutton; Nikhil Patel; Kyle Martin; Devinder Singh

2008-02-01

72

Thermal batteries for aircraft emergency power  

NASA Astrophysics Data System (ADS)

Thermal batteries are being proposed for the Emergency Power System for aircraft. Thermal batteries are a reserve type battery which is essentially inert until activated. Thermal batteries can generate full power in several seconds and nominally produce 20 WHr/Ib and operate over a temperature range of -65 deg to 165 deg. Thermal batteries have a proven field storage life exceeding 25 years. They contain no liquids, can be maintained at any attitude, operate at any altitude, and do not leak any toxic or noxious materials. Expended thermal batteries contain no lead or cadmium and do not represent a significant disposal or environmental problem. Thermal batteries have a thirty year history of excellent performance providing on-board power for missiles and other weapons and have a proven safety record with no field injuries ever. Thermal batteries have a relatively low cost of initial ownership and require no maintenance.

Ryan, David M.

1993-02-01

73

Magnetohydrodynamic power generation  

NASA Astrophysics Data System (ADS)

Experimental and theoretical research has been conducted to investigate phenomena expected to be important in the development of MHD power generation. The areas investigated were: Boundary layers and generator loss mechanisms, plasma nonuniformities and instabilities, investigation of rod electrodes, seed-slag interaction and the reactivity of coal, disk generators, and temperature diagnostic techniques for combustion MHD plasmas. Brief summaries of the principal results and their expected impact for large scale MHD generators are given: (1) Secondary flows driven by transverse Lorentz forces are predicted to be a major phenomenon in large-scale generators. We have studied this phenomenon by conducting experiments in a laboratory-scale facility in which a high magnetic interaction parameter for driving such secondary flows has been achieved by applying axial current and by maintaining low flow rates. The results of measurements of transverse velocities show that the resulting secondary flows consist of intense, large-scale vortices which convectively distort the cross-plane distribution of important plasma properties. (2) An experimental approach based on measurements of the phase difference of acoustic waves excited in an MHD generator has been successfully employed to detect changes caused by the magnetoacoustic interaction. Predictions for large-scale MHD generators, based upon this same theory, suggest that the possible detrimental effects of the magnetoacoustic interaction cannot be ignored, and must be given serious attention in the design of large-scale facilities.

Kruger, C. H.; Eustis, R. H.; Mitchner, M.; Self, S. A.; Nakamura, T.

1985-06-01

74

Wind power. [electricity generation  

NASA Technical Reports Server (NTRS)

A historical background on windmill use, the nature of wind, wind conversion system technology and requirements, the economics of wind power and comparisons with alternative systems, data needs, technology development needs, and an implementation plan for wind energy are presented. Considerable progress took place during the 1950's. Most of the modern windmills feature a wind turbine electricity generator located directly at the top of their rotor towers.

Savino, J. M.

1975-01-01

75

Spectrophotovoltaic orbital power generation  

NASA Technical Reports Server (NTRS)

The feasibilty of a spectrophotovoltaic orbital power generation system that optically concentrates solar energy is demonstrated. A dichroic beam-splitting mirror is used to divide the solar spectrum into two wavebands. Absorption of these wavebands by GaAs and Si solar cell arrays with matched energy bandgaps increases the cell efficiency while decreasing the amount of heat that must be rejected. The projected cost per peak watt if this system is $2.50/W sub p.

Onffroy, J. R.

1980-01-01

76

High power microwave generator  

DOEpatents

A microwave generator efficiently converts the energy of an intense relativistic electron beam (REB) into a high-power microwave emission using the Smith-Purcell effect which is related to Cerenkov radiation. Feedback for efficient beam bunching and high gain is obtained by placing a cylindrical Smith-Purcell transmission grating on the axis of a toroidal resonator. High efficiency results from the use of a thin cold annular highly-magnetized REB that is closely coupled to the resonant structure.

Ekdahl, Carl A. (Albuquerque, NM) [Albuquerque, NM

1986-01-01

77

Investing in Power Generation  

Microsoft Academic Search

\\u000a In light of considerable political and market risk emanating from energy market liberalization, global warming, and rapid\\u000a technological change, adequate investment in power generation capacity is of paramount importance for ensuring the security\\u000a of electricity supply and a smooth transition to a more decentralized, energy-efficient and renewable energy system. Consequently,\\u000a investors have to use more sophisticated approaches to determine optimal

Reinhard Madlener; Rik W. De Doncker

78

Micro electret power generators  

NASA Astrophysics Data System (ADS)

The taming of electricity and its widespread use allows people to see in the dark, to speak to one another instantaneously across the earth, and it allows retrieval of data from instruments sent out of the solar system. It is right to expect that the uses and demand for electricity will continue to grow, and to extend the ability to generate electricity; here two new micromachined devices for converting mechanical energy into electrical energy are presented. Aided by the wealth of micromachining process technology, generators that use an oscillatory motion to modify the physical structure of a capacitor with a built-in electric field provided by a permanent electret have been designed, built, and tested. The electret creates an electric field inside the capacitor structure, which induces mirror charge at some potential. The modification of the capacitor then generates an alternating displacement current through an external circuit, which provides useful electrical power. The electret microphone is a similar well known device for converting pressure waves into electrical signals by varying the distance between two charged capacitive plates. This work explores and proves feasible the ability to use mechanical forces to change the overlapping area of a charged capacitor structure and using mechanical forces to move a liquid into the gap of a charged capacitor structure, changing its permittivity to produce electricity. This work demonstrates 2.5mW of power from a 2cm diameter rotary generator at 12kRPM and 10[micro]w for a 0.1cm3 linear shaking generator at 60Hz.

Boland, Justin

79

Microfabricated thermoelectric power-generation devices  

NASA Technical Reports Server (NTRS)

A device for generating power to run an electronic component. The device includes a heat-conducting substrate (composed, e.g., of diamond or another high thermal conductivity material) disposed in thermal contact with a high temperature region. During operation, heat flows from the high temperature region into the heat-conducting substrate, from which the heat flows into the electrical power generator. A thermoelectric material (e.g., a BiTe alloy-based film or other thermoelectric material) is placed in thermal contact with the heat-conducting substrate. A low temperature region is located on the side of the thermoelectric material opposite that of the high temperature region. The thermal gradient generates electrical power and drives an electrical component.

Fleurial, Jean-Pierre (Inventor); Ryan, Margaret A. (Inventor); Borshchevsky, Alex (Inventor); Phillips, Wayne (Inventor); Kolawa, Elizabeth A. (Inventor); Snyder, G. Jeffrey (Inventor); Caillat, Thierry (Inventor); Kascich, Thorsten (Inventor); Mueller, Peter (Inventor)

2002-01-01

80

Microfabricated thermoelectric power-generation devices  

NASA Technical Reports Server (NTRS)

A device for generating power to run an electronic component. The device includes a heat-conducting substrate (composed, e.g., of diamond or another high thermal conductivity material) disposed in thermal contact with a high temperature region. During operation, heat flows from the high temperature region into the heat-conducting substrate, from which the heat flows into the electrical power generator. A thermoelectric material (e.g., a BiTe alloy-based film or other thermoelectric material) is placed in thermal contact with the heat-conducting substrate. A low temperature region is located on the side of the thermoelectric material opposite that of the high temperature region. The thermal gradient generates electrical power and drives an electrical component.

Fleurial, Jean-Pierre (Inventor); Ryan, Margaret A. (Inventor); Borshchevsky, Alex (Inventor); Phillips, Wayne (Inventor); Kolawa, Elizabeth A. (Inventor); Snyder, G. Jeffrey (Inventor); Caillat, Thierry (Inventor); Kascich, Thorsten (Inventor); Mueller, Peter (Inventor)

2004-01-01

81

Thermophillic and thermotolerant fungi isolated from the thermal effluent of nuclear power generating reactors: dispersal of human opportunistic and veterinary pathogenic fungi.  

PubMed

Over a period of a year, samples of water, foam, microbial mat, soil and air were obtained from areas associated with the cooling canal of a nuclear power station. The seventeen sample sites included water in the cooling canal that was thermally enriched and soil and water adjacent to, upstream, downstream and at a distance from the generator. Air samples were taken at the plant and at various distances from the plant. Fifty-two species of thermotolerant and thermophilic fungi were isolated. Of these, eleven species are grouped as opportunistic Mucorales or opportunistic Aspergillus sp. One veterinary pathogen was also isolated (Dactylaria gallopava). The opportunistic/pathogenic fungi were found primarily in the intake bay, the discharge bay and the cooling canal. Smaller numbers were obtained at both upstream and downstream locations. Soil samples near the cooling canal reflected an enrichment of thermophilous organisms, the previously mentioned opportunistic Mucorales and Aspergillus spp. Their numbers were found to be greater than that usually encountered in a mesophilic environment. However, air and soil samples taken at various distances from the power station indicated no greater abundance of these thermophilous fungi than would be expected from a thermal enriched environment. Our results indicate that there was no significant dissemination of thermophilous fungi from the thermal enriched effluents to the adjacent environment. These findings are consistent with the results of other investigators. PMID:7374746

Rippon, J W; Gerhold, R; Heath, M

1980-03-31

82

Power generation, operation, and control  

Microsoft Academic Search

This book discusses the economic and engineering aspects used in the planning, operating, and controlling of power generation and transmission systems for electric utilities. It presents advanced mathematical and operations research methods used for electric power engineering problems. It covers methods currently applied in the control and operation of electric power systems. The contents are characteristics of power generation units.

A. J. Wood; B. F. Wollenberg

1984-01-01

83

Thermal energy from a biogas engine/generator system  

SciTech Connect

A biogas fueled engine/generator equipped with heat recovery apparatus and thermal storage is described. The thermal energy is used to fuel a liquid fuel plant. Heat recovery is quantified and the static and dynamic performance of the thermal storage is described. At 1260 rpm the engine/generator produces 21 kW of electric power and 2500 kJ/min of thermal energy.

Stahl, T.; Fischer, J.R.; Harris, F.D.

1982-12-01

84

Innovative technologies for full utilization of ash generated at coal-fired thermal power stations for producing alumina and construction materials  

NASA Astrophysics Data System (ADS)

The possibility of full 100% usage of ash from coal-fired thermal power stations for producing raw materials for the cement and alumina industries is considered, and it is shown that comprehensive processing of ash from coal-fired thermal power stations is required for this purpose.

Delitsyn, L. M.; Vlasov, A. S.; Borodina, T. I.; Ezhova, N. N.; Sudareva, S. V.

2013-04-01

85

Piezoelectric, Solar and Thermal Energy Harvesting for Hybrid Low-Power Generator Systems With Thin-Film Batteries.  

National Technical Information Service (NTIS)

The harvesting of ambient energy to power small electronic components has received tremendous attention over the last decade. The research goal in this field is to enable self-powered electronic components for use particularly in wireless sensing and meas...

A. Erturk D. J. Inman N. Kong P. Gambier S. R. Anton

2012-01-01

86

Windmill power generator  

SciTech Connect

A windmill powered generator having one or a plurality of wind operated motor units, each being operably connected to a single power drive shaft to effect rotation of said drive shaft regardless of the rotational direction of the wind operated rotary units is described. Each rotary unit is provided with a crank shaft having one or more crank arms carried thereby, the drive shaft having one frictional hub associated with each crank arm. A drive belt extends from each crank arm around its associated hub and is yieldably secured to either the frame or to the end of another drive belt attached to an oppositely oriented crank arm whereby movement of the crank arm in a direction away from the drive shaft increases the friction between the drive belt and the frictional hub causing rotation of the drive shaft and whereby movement of the crank arm in a direction toward the drive shaft decreases the friction between the drive belt and the frictional hub thereby allowing the belt to slip about the frictional hub.

Oakes, R.M.

1980-12-30

87

Solar Thermal Electric Power Systems.  

National Technical Information Service (NTIS)

Results of research to identify cost effective solar thermal electric power systems are given. Parametric performance and cost models were developed for concentrating collector, heat transport, and heat storage subsystems. Dynamic programming methods to s...

1974-01-01

88

Windmill structure and power generator  

SciTech Connect

A windpower generator includes a cupped blade design to be assembled from flat module sheets together with a resiliently biased mount to provide automatic feathering with a consequent speed control. A generator or alternating generator to feed electric output to an existing power system, as, for example, a residence or small business establishment, is associated with the windmill to serve as a counterbalance in the mounting and to cooperate with the self-governing blade assembly. A switching circuit is connected to feed generator power to the local utility power lines when net power is available at the winddriven alternator and in phase with utility power.

Schott, L.A.; Schott, R.A.

1982-02-23

89

Wind power electrical generator system  

Microsoft Academic Search

A wind power electrical generator system having improved efficiency including a wind mill which activates an air compressor to generate a supply of pressurized air. An air motor activated by the supply of pressurized air drives a generator to produce electrical power. A waste air recovery mechanism, activated by the waste air from the air motor produces rotary energy assisting

Allison

1984-01-01

90

Homopolar generator power supply system  

Microsoft Academic Search

A high-energy, high-current homopolar generator pulsed power supply system that is compact and field portable. The power supply system includes a homopolar generator (HPG), an auxiliary supply and drive system, both mounted on a skid frame, and a control system coupled to the HPG and drive system. The homopolar generator has a split rotor with insulation between the halves and

W. F. Weldon; J. H. Gully

1985-01-01

91

Dynamic power systems for power generation  

NASA Technical Reports Server (NTRS)

The characteristics of dynamic power systems have considerable potential value, especially for the space station. The base of technology that makes these dynamic power systems practical is reviewed. The following types of power-generating systems are examined herein: organic Rankine cycle, potassium Rankine cycle, Brayton cycle, and Stirling cycle.

English, R. E.

1984-01-01

92

Independent power generator  

NASA Technical Reports Server (NTRS)

A gas turbine powered aircraft auxiliary power system is described which is capable of efficiently supplying all aircraft auxiliary services both in flight and on the ground and is further capable of operating independently of the aircraft main engines. The system employs multiple gas turbine compressor stages, thereby accomplishing cabin pressurization, ventilation and heating.

Young, R. N. (inventor)

1978-01-01

93

Solar power generating system  

Microsoft Academic Search

A volatile liquid is circulated through a normally closed circuit, including expansion tubes within an expansion chamber where the sun's rays are focused on the tubes to heat the liquid, transforming it to an expanding gas to drive a fluid-operated motor, also in the circuit. The motor may drive a mechanical load or an electric generator. The generator drives a

1981-01-01

94

Achieving Maximum Power in Thermoelectric Generation with Simple Power Electronics  

NASA Astrophysics Data System (ADS)

A thermoelectric generator typically delivers a relatively low power output, and hence it is of great practical importance to determine a design and operating condition close to those which can provide the maximum attainable power. To maintain a favorable condition for the maximum power output, power electronics circuits are usually applied. One of the simplest methods is to control the operating voltage at half the open-circuit voltage, assuming that the typical impedance-matching condition, in which the load and internal resistances are matched, yields the maximum power output. However, recent investigations have shown that, when external thermal resistances exist between the thermoelectric modules and thermal reservoirs, the impedance-matching condition is not identical to the condition for the maximum power output. In this article, it is argued that, although the impedance-matching condition is not the condition for maximum power output, the maximum power is still achievable when the operating voltage is kept at half the open-circuit voltage. More precisely, it is shown that the typical V- I curve for thermoelectric generators must show approximately linear behavior, which justifies the use of a simple strategy in thermoelectric power generation applications. The conditions for the validity of the approximation are mathematically discussed, supported by a few examples. Experimental evidence at room temperature is also provided.

Youn, Nari; Lee, Hohyun; Wee, Daehyun; Gomez, Miguel; Reid, Rachel; Ohara, Brandon

2014-06-01

95

Power generation systems and methods  

NASA Technical Reports Server (NTRS)

A power generation system includes a plurality of submerged mechanical devices. Each device includes a pump that can be powered, in operation, by mechanical energy to output a pressurized output liquid flow in a conduit. Main output conduits are connected with the device conduits to combine pressurized output flows output from the submerged mechanical devices into a lower number of pressurized flows. These flows are delivered to a location remote of the submerged mechanical devices for power generation.

Jones, Jack A. (Inventor); Chao, Yi (Inventor)

2011-01-01

96

Compact, lightweight, superconducting power generators  

Microsoft Academic Search

Many future military systems will depend heavily on high electrical power input ranging from 100's kilowatts up to the multimegawatt level. These weapon systems include electromagnetic launch applications as well as electrically driven directed energy weapons (DEW), such as high power microwaves and solid state lasers. These power generation subsystems must often be packaged using limited space and strict weight

Paul N. Barnes; Gregory L. Rhoads; Justin C. Tolliver; Michael D. Sumption; Kevin W. Schmaeman

2004-01-01

97

Compact, lightweight, superconducting power generators  

Microsoft Academic Search

Many future military systems will depend heavily on high electrical power input ranging from hundreds of kilowatts up to the multimegawatt level. These weapon systems include electromagnetic launch applications as well as electrically driven directed energy weapons (DEW), such as high-power microwaves and solid-state lasers. These power generation subsystems must often be packaged using limited space and strict weight limits

Paul N. Barnes; Gregory L. Rhoads; Justin C. Tolliver; Michael D. Sumption; Kevin W. Schmaeman

2005-01-01

98

Pulsed Power Generation Techniques  

Microsoft Academic Search

This paper describes the evolution of high voltage pulsed-power (HVPP) technology from its inception to the present state, particularly focusing on its applicability and effectiveness for a variety of industrial applications. HVPP techniques that have been reported are discussed, highlighting advantages and disadvantages. A detailed analysis of four modern techniques that are based on capacitive energy compression elements, is presented

D. J. Thrimawithana; U. K. Madawala; R. C. B. Woodhead

2006-01-01

99

High power microwave generator  

DOEpatents

A device (10) for producing high-powered and coherent microwaves is described. The device comprises an evacuated, cylindrical, and hollow real cathode (20) that is driven to inwardly field emit relativistic electrons. The electrons pass through an internally disposed cylindrical and substantially electron-transparent cylindrical anode (24), proceed toward a cylindrical electron collector electrode (26), and form a cylindrical virtual cathode (32). Microwaves are produced by spatial and temporal oscillations of the cylindrical virtual cathode (32), and by electrons that reflex back and forth between the cylindrical virtual cathode (32) and the cylindrical real cathode (20).

Minich, Roger W. (Patterson, CA)

1988-01-01

100

Spectrophotovoltaic orbital power generation  

NASA Technical Reports Server (NTRS)

A subscale model of a photovoltaic power system employing spectral splitting and 1000:1 concentration was fabricated and tested. The 10-in. aperture model demonstrated 15.5% efficiency with 86% of the energy produced by a GaAs solar cell and 14% of the energy produced by an Si cell. The calculated efficiency of the system using the same solar cells, but having perfect optics, would be approximately 20%. The model design, component measurements, test results, and mathematical model are presented.

Knowles, G.; Carroll, J.

1983-01-01

101

Wind Power Charged Aerosol Generator  

SciTech Connect

This describes experimental results on a Charged Aerosol Wind/Electric Power Generator, using Induction Electric Charging with a water jet issuing under water pressure from a small diameter (25-100 ..mu..m) orifice.

Marks, A.M.

1980-07-01

102

Tide operated power generating apparatus  

SciTech Connect

An improved tide operated power generating apparatus is disclosed in which a hollow float, rising and falling with the ocean tide, transmits energy to a power generator. The improvement comprises means for filling the float with water during the incoming tide to provide a substantial increase in the float dead weight during the outgoing tide. Means are further provided to then empty the float before the outgoing tide whereby the float becomes free to rise again on the next incoming tide.

Kertzman, H. Z.

1981-02-03

103

Coal and Nuclear Power Generation  

Microsoft Academic Search

\\u000a Historically the first electric power plants delivering large quantities of electric energy were hydro-electric. In 1895,\\u000a Westinghouse built the first AC electric power generator in Niagara Falls by passing water flow from the Falls through a turbine\\u000a that induced electric currents in copper windings. General Electric built high-power grid lines that took the 1.1 MWe of electricity\\u000a to Buffalo, New

Jeff W. Eerkens

104

Synopsis of Magnetohydrodynamic Power Generation  

NASA Technical Reports Server (NTRS)

Concise summary of magnetohydrodynamic (MHD) theory, history, and future trends presented in report. Worldwide research on MHD covered, and selected data from key research projects included. Magnetohydrodynamic generator produces electric current by passing fluid at high speed through strong magnetic field. Fluid ionized gas, plasma, or liquid metal. Magnetohydrodynamic generators offer potential for high efficiency, low power cost, and cleaner emissions.

Smith, J. L.

1986-01-01

105

Fresnel Concentrators for Space Solar Power and Solar Thermal Propulsion.  

National Technical Information Service (NTIS)

Large deployable Fresnel concentrators are applicable to solar thermal propulsion and multiple space solar power generation concepts. These concentrators can be used with thermophotovoltaic, solar thermionic, and solar dynamic conversion systems. Thin pol...

R. Bradford R. W. Parks

2001-01-01

106

An overview of modelling and simulation of thermal power plant  

Microsoft Academic Search

power plants constitute the largest proportion of installed capability in global power generation system, which consumes large quantities of coal. Therefore achieving optimal operation of thermal power units, improving its efficiency and reducing the coal consumption is of great significance for the reduction of greenhouse gas and pollutants emissions. Modelling and simulation is the base of optimal operation and control

Changliang Liu; Hong Wang; Jinliang Ding; Chenggang Zhen

2011-01-01

107

Assessment of Japan's Optimal Power Generation Mix Considering Massive Deployment of Variable Renewable Power Generation  

NASA Astrophysics Data System (ADS)

This paper analyzes Japan's optimal power generation mix considering massive deployment of solar photovoltaic (PV) system and wind power generation. The extensive introduction of PV system and wind power system are expected to play an important role in addressing energy security and climate change concern in Japan. Considering this expected large-scale deployment of PV system in electric power system, it is necessary to investigate the optimal power generation mix which is technologically capable of controlling and accommodating the intermittent output-power fluctuation inherently derived from PV and wind energy system. On these backgrounds, we develop optimal power generation mix model, explicitly analyzing the impact of output fluctuation in variable renewable in detailed resolution of time interval like 10 minutes at consecutive 365 days, with the role of stationary battery technology incorporated. Simulation results reveal that considerable deployment of those variable renewables do not necessarily require the scale of battery capacity similar as that of variable renewable capacity, due to quick load following treatment by thermal power plants, pumped-storage hydro power and battery technology over renewable output fluctuation.

Komiyama, Ryoichi; Fujii, Yasumasa

108

Kinetics of thermal donor generation in silicon  

NASA Technical Reports Server (NTRS)

The generation kinetics of thermal donors at 450 C in Czochralski-grown silicon was found to be altered by high-temperature preannealing (e.g., 1100 C for 30 min). Thus, when compared with as-grown Si, high-temperature preannealed material exhibits a smaller concentration of generated thermal donors and a faster thermal donor saturation. A unified mechanism of nucleation and oxygen diffusion-controlled growth (based on solid-state plate transformation theory) is proposed to account for generation kinetics of thermal donors at 450 C, in as-grown and high-temperature preannealed Czochralski silicon crystals. This mechanism is consistent with the main features of the models which have been proposed to explain the formation of oxygen thermal donors in silicon.

Mao, B.-Y.; Lagowski, J.; Gatos, H. C.

1984-01-01

109

Entropy generation method to quantify thermal comfort.  

PubMed

The present paper presents a thermodynamic approach to assess the quality of human-thermal environment interaction and quantify thermal comfort. The approach involves development of entropy generation term by applying second law of thermodynamics to the combined human-environment system. The entropy generation term combines both human thermal physiological responses and thermal environmental variables to provide an objective measure of thermal comfort. The original concepts and definitions form the basis for establishing the mathematical relationship between thermal comfort and entropy generation term. As a result of logic and deterministic approach, an Objective Thermal Comfort Index (OTCI) is defined and established as a function of entropy generation. In order to verify the entropy-based thermal comfort model, human thermal physiological responses due to changes in ambient conditions are simulated using a well established and validated human thermal model developed at the Institute of Environmental Research of Kansas State University (KSU). The finite element based KSU human thermal computer model is being utilized as a "Computational Environmental Chamber" to conduct series of simulations to examine the human thermal responses to different environmental conditions. The output from the simulation, which include human thermal responses and input data consisting of environmental conditions are fed into the thermal comfort model. Continuous monitoring of thermal comfort in comfortable and extreme environmental conditions is demonstrated. The Objective Thermal Comfort values obtained from the entropy-based model are validated against regression based Predicted Mean Vote (PMV) values. Using the corresponding air temperatures and vapor pressures that were used in the computer simulation in the regression equation generates the PMV values. The preliminary results indicate that the OTCI and PMV values correlate well under ideal conditions. However, an experimental study is needed in the future to fully establish the validity of the OTCI formula and the model. One of the practical applications of this index is that could it be integrated in thermal control systems to develop human-centered environmental control systems for potential use in aircraft, mass transit vehicles, intelligent building systems, and space vehicles. PMID:12182196

Boregowda, S C; Tiwari, S N; Chaturvedi, S K

2001-12-01

110

Entropy generation method to quantify thermal comfort  

NASA Technical Reports Server (NTRS)

The present paper presents a thermodynamic approach to assess the quality of human-thermal environment interaction and quantify thermal comfort. The approach involves development of entropy generation term by applying second law of thermodynamics to the combined human-environment system. The entropy generation term combines both human thermal physiological responses and thermal environmental variables to provide an objective measure of thermal comfort. The original concepts and definitions form the basis for establishing the mathematical relationship between thermal comfort and entropy generation term. As a result of logic and deterministic approach, an Objective Thermal Comfort Index (OTCI) is defined and established as a function of entropy generation. In order to verify the entropy-based thermal comfort model, human thermal physiological responses due to changes in ambient conditions are simulated using a well established and validated human thermal model developed at the Institute of Environmental Research of Kansas State University (KSU). The finite element based KSU human thermal computer model is being utilized as a "Computational Environmental Chamber" to conduct series of simulations to examine the human thermal responses to different environmental conditions. The output from the simulation, which include human thermal responses and input data consisting of environmental conditions are fed into the thermal comfort model. Continuous monitoring of thermal comfort in comfortable and extreme environmental conditions is demonstrated. The Objective Thermal Comfort values obtained from the entropy-based model are validated against regression based Predicted Mean Vote (PMV) values. Using the corresponding air temperatures and vapor pressures that were used in the computer simulation in the regression equation generates the PMV values. The preliminary results indicate that the OTCI and PMV values correlate well under ideal conditions. However, an experimental study is needed in the future to fully establish the validity of the OTCI formula and the model. One of the practical applications of this index is that could it be integrated in thermal control systems to develop human-centered environmental control systems for potential use in aircraft, mass transit vehicles, intelligent building systems, and space vehicles.

Boregowda, S. C.; Tiwari, S. N.; Chaturvedi, S. K.

2001-01-01

111

Heat generating compositions for thermal batteries  

NASA Astrophysics Data System (ADS)

Thermal batteries are widely used as independent current sources with long storage life and the ability to operate over a wide ambient temperature range. A number of pyrotechnic materials may as rule be used as sources of thermal energy to provide ionic conduction in a molten electrolyte and to maintain the working temperature of the battery during the discharge of the electrochemical elements. The requirements for heat sources in thermal batteries are described and different heat generating compositions are reviewed.

Sheptunov, V. N.

1991-03-01

112

Investigations for biogas operated MHD power generators  

SciTech Connect

Biogas is produced from the anaerobic fermentation of the organic matter containing cellulose, such as agricultural wastes, human wastes, animal wastes, etc. It contains methane (50-70%), carbon dioxide (30-50%), and very small amounts of hydrogen and hydrogen sulphide. Adequate quantities of raw material to generate biogas are normally available in rural areas, and therefore, there is a possibility that almost all the energy requirements of the rural sector may be fulfilled by biogas. Presently in the rural sector, biogas is used mainly to provide thermal energy (for cooking, etc.), and up to a limited extent, to meet the electrical energy requirements by running electrical generators with engines powered by a mixture of oil and biogas. In this paper, the authors propose a scheme in which biogas can be used to generate electricity more efficiently by using magnetohydrodynamic (MHD) power generators. Investigations have been carried out to make feasibility studies for biogas-operated open cycle MHD power generators. Composition, temperature and electrical conductivity of the seeded (with potassium) combustion products of biogas-air/oxygen systems have been analytically investigated for different percentages of CO/sub 2/ in biogas and at various combustor pressures for a seeding ratio of 1 percent by weight. The effect of preheating and enrichment of air on temperature and electrical conductivity of the seeded combustion plasmas has also been studied.

Dahiya, R.P.; Chand, A.; Sharma, S.C.

1983-12-01

113

Power Losses and Thermal Modeling of A Voltage Source Inverter.  

National Technical Information Service (NTIS)

This thesis presents thermal and power loss models of a three phase IGBT voltage source inverter used in the design of the 625KW fuel cell and reformer demonstration which is a top priority for the Office of Naval Research. The ability to generate thermal...

M. C. Oberdorf

2006-01-01

114

Chemical energy storage system for SEGS solar thermal power plant  

Microsoft Academic Search

In October 1988, a symposium was held in Helendale, California, to discuss thermal energy storage (TES) concepts applicable to medium temperature (200 to 400 C) solar thermal electric power plants, in general, and the solar electric generating system (SEGS) plants developed by Luz International, in particular. Chemical reaction energy storage based on the reversible reaction between metal oxides and metal

D. R. Brown; J. L. Lamarche; G. E. Spanner

1991-01-01

115

Next Generation Geothermal Power Plants  

SciTech Connect

A number of current and prospective power plant concepts were investigated to evaluate their potential to serve as the basis of the next generation geothermal power plant (NGGPP). The NGGPP has been envisaged as a power plant that would be more cost competitive (than current geothermal power plants) with fossil fuel power plants, would efficiently use resources and mitigate the risk of reservoir under-performance, and minimize or eliminate emission of pollutants and consumption of surface and ground water. Power plant concepts were analyzed using resource characteristics at ten different geothermal sites located in the western United States. Concepts were developed into viable power plant processes, capital costs were estimated and levelized busbar costs determined. Thus, the study results should be considered as useful indicators of the commercial viability of the various power plants concepts that were investigated. Broadly, the different power plant concepts that were analyzed in this study fall into the following categories: commercial binary and flash plants, advanced binary plants, advanced flash plants, flash/binary hybrid plants, and fossil/geothed hybrid plants. Commercial binary plants were evaluated using commercial isobutane as a working fluid; both air-cooling and water-cooling were considered. Advanced binary concepts included cycles using synchronous turbine-generators, cycles with metastable expansion, and cycles utilizing mixtures as working fluids. Dual flash steam plants were used as the model for the commercial flash cycle. The following advanced flash concepts were examined: dual flash with rotary separator turbine, dual flash with steam reheater, dual flash with hot water turbine, and subatmospheric flash. Both dual flash and binary cycles were combined with other cycles to develop a number of hybrid cycles: dual flash binary bottoming cycle, dual flash backpressure turbine binary cycle, dual flash gas turbine cycle, and binary gas turbine cycle. Results of this study indicate that dual flash type plants are preferred at resources with temperatures above 400 F. Closed loop (binary type) plants are preferred at resources with temperatures below 400 F. A rotary separator turbine upstream of a dual flash plant can be beneficial at Salton Sea, the hottest resource, or at high temperature resources where there is a significant variance in wellhead pressures from well to well. Full scale demonstration is required to verify cost and performance. Hot water turbines that recover energy from the spent brine in a dual flash cycle improve that cycle's brine efficiency. Prototype field tests of this technology have established its technical feasibility. If natural gas prices remain low, a combustion turbine/binary hybrid is an economic option for the lowest temperature sites. The use of mixed fluids appear to be an attractive low risk option. The synchronous turbine option as prepared by Barber-Nichols is attractive but requires a pilot test to prove cost and performance. Dual flash binary bottoming cycles appear promising provided that scaling of the brine/working fluid exchangers is controllable. Metastable expansion, reheater, Subatmospheric flash, dual flash backpressure turbine, and hot dry rock concepts do not seem to offer any cost advantage over the baseline technologies. If implemented, the next generation geothermal power plant concept may improve brine utilization but is unlikely to reduce the cost of power generation by much more than 10%. Colder resources will benefit more from the development of a next generation geothermal power plant than will hotter resources. All values presented in this study for plant cost and for busbar cost of power are relative numbers intended to allow an objective and meaningful comparison of technologies. The goal of this study is to assess various technologies on an common basis and, secondarily, to give an approximate idea of the current costs of the technologies at actual resource sites. Absolute costs at a given site will be determined by the specifics of a given pr

Brugman, John; Hattar, Mai; Nichols, Kenneth; Esaki, Yuri

1995-09-01

116

Homopolar generator power supply system  

SciTech Connect

A high-energy, high-current homopolar generator pulsed power supply system that is compact and field portable. The power supply system includes a homopolar generator (HPG), an auxiliary supply and drive system, both mounted on a skid frame, and a control system coupled to the HPG and drive system. The homopolar generator has a split rotor with insulation between the halves and a recess in the periphery. A stator ring and field coil, for producing a magnetic field through which the rotor halves make two simultaneous voltage-generating passes, are disposed within the recess in the rotor. Air-actuated brush mechanisms inside and outside the recess contact surfaces of the rotor and collect discharge current. The auxiliary supply and drive system includes a motoring system comprising hydraulic motors for driving the HPG to speed, a bearing lubrication system, a generator for energizing the field coil, and a brush actuator air supply system, all of which are driven by a prime mover. The control system comprises a logic controller for executing a prescribed sequence of steps including turning on the prime mover, initiating motoring of the HPG, energizing the field coil, and initiating the discharge of electrical current.

Weldon, W. F.; Gully, J. H.

1985-10-01

117

Experiments on thermal stratification in inlet nozzle of steam generator  

Microsoft Academic Search

Nuclear power plant components suffer pipe shedding, cracking, thermal fatigue, bending and supporting bracket breakage during\\u000a their life span. Notably, the horizontal inlet nozzle of steam generator is prone to thermal stratification frequently due\\u000a to its operational characteristics. As a result, PWRs in many countries including the U.S.A. suffered a lot of pipe cracks\\u000a and leakages around the late 1970s,

Sang-Nyung Kim; Cheol-Hong Kim; Bum-Su Youn; Hag-Ki Yum

2007-01-01

118

A prototype microthermophotovoltaic power generator  

NASA Astrophysics Data System (ADS)

A prototype microthermophotovoltaic (micro-TPV) power generator is described in this letter. The system is made of a SiC (silicon carbide) emitter, a simple nine-layer dielectric filter, and a GaSb (gallium antimony) photovoltaic cell array. In a microcombustor of 0.113 cm3 in volume, when the flow rate of hydrogen is 4.20 g/h, the micro-TPV system is able to deliver an electrical power output of 1.02 W, corresponding to an open-circuit electrical voltage of 2.28 V and a short-circuit current of 0.59 A. The prototype of the micro-TPV system will make it possible for us to substitute batteries with micropower generators in micromechanical devices in the near future.

Yang, W. M.; Chou, S. K.; Shu, C.; Li, Z. W.; Xue, H.

2004-05-01

119

Reactive power capability of unified DFIG for wind power generation  

Microsoft Academic Search

This paper, first, develops the reactive power capabilities of wind power generator and then discusses reactive power ancillary services issues related to the wind farms in the electricity market. Presently, the doubly fed induction generator (DFIG) system, with partial rated power electronic converters in the rotor circuit, is the most popular and widely used for the wind power generation due

S. N. Singh; Jacob Østergaard; Bharat Singh

2010-01-01

120

Thermal control system for Space Station Freedom photovoltaic power module  

NASA Technical Reports Server (NTRS)

The electric power for Space Station Freedom (SSF) is generated by the solar arrays of the photovoltaic power modules (PVM's) and conditioned, controlled, and distributed by a power management and distribution system. The PVM's are located outboard of the alpha gimbals of SSF. A single-phase thermal control system is being developed to provide thermal control of PVM electrical equipment and energy storage batteries. This system uses ammonia as the coolant and a direct-flow deployable radiator. The description and development status of the PVM thermal control system is presented.

Hacha, Thomas H.; Howard, Laura

1994-01-01

121

Research Applied to Solar-Thermal Power Systems.  

National Technical Information Service (NTIS)

The function of a solar-thermal power system is to supply solar-generated heat to the turbines of an electric power plant. The basic system presently being considered under this program is composed of an array of collectors (consisting of a parabolic refl...

W. B. Bienert E. R. G. Eckert J. M. Hammer R. C. Jordan J. W. Ramsey

1973-01-01

122

Chemical energy storage system for SEGS solar thermal power plant  

Microsoft Academic Search

The Pacific Northwest Laboratory evaluated the potential feasibility of using chemical energy storage at the Solar Electric Generating System (SEGS) power plants developed by Luz International. Like sensible or latent heat energy storage systems, chemical energy storage can be beneficially applied to solar thermal power plants to dampen the impact of cloud transients, extend the daily operating period, and\\/or allow

D. R. Brown; J. L. Lamarche; G. E. Spanner

1992-01-01

123

The present status for thermal discharge of nuclear power plant  

Microsoft Academic Search

All the nuclear power plants in Japan are located on the seaside, and use an great amount of sea water for cooling condenser like fossil power generation plants. The resultant thermal discharge which may have an impact on the environment of the surrounding areas is one of the most important issues to be given a serious consideration, next to the

I Kokaji

1995-01-01

124

Technical and Economic Feasibility of a Thermal Gradient Utilization Cycle (TGUC) Power Plant. Final Report.  

National Technical Information Service (NTIS)

The technical and economic feasibility of a Thermal Gradient Utilization Cycle (TGUC), a new concept in power generation, was investigated. Power is generated by exploiting the natural atmosheric temperature gradient. A low grade energy source is used to ...

A. M. Raiji D. A. Renfroe T. R. Lalk

1980-01-01

125

Local control of reactive power by distributed photovoltaic generators  

SciTech Connect

High penetration levels of distributed photovoltaic (PV) generation on an electrical distribution circuit may severely degrade power quality due to voltage sags and swells caused by rapidly varying PV generation during cloud transients coupled with the slow response of existing utility compensation and regulation equipment. Although not permitted under current standards for interconnection of distributed generation, fast-reacting, VAR-capable PV inverters may provide the necessary reactive power injection or consumption to maintain voltage regulation under difficult transient conditions. As side benefit, the control of reactive power injection at each PV inverter provides an opportunity and a new tool for distribution utilities to optimize the performance of distribution circuits, e.g. by minimizing thermal losses. We suggest a local control scheme that dispatches reactive power from each PV inverter based on local instantaneous measurements of the real and reactive components of the consumed power and the real power generated by the PVs. Using one adjustable parameter per circuit, we balance the requirements on power quality and desire to minimize thermal losses. Numerical analysis of two exemplary systems, with comparable total PV generation albeit a different spatial distribution, show how to adjust the optimization parameter depending on the goal. Overall, this local scheme shows excellent performance; it's capable of guaranteeing acceptable power quality and achieving significant saving in thermal losses in various situations even when the renewable generation in excess of the circuit own load, i.e. feeding power back to the higher-level system.

Chertkov, Michael [Los Alamos National Laboratory; Turitsyn, Konstantin [Los Alamos National Laboratory; Sulc, Petr [Los Alamos National Laboratory; Backhaus, Scott [Los Alamos National Laboratory

2010-01-01

126

Materials testing for central receiver solar-thermal power systems  

Microsoft Academic Search

The determination of specific elevated temperature mechanical properties of materials used for critical components in solar control receiver power systems is described. The biaxial creep fatigue testing of type 316H stainless steel superheater tubing is discussed. A survey of sodium effects on candidate materials for solar-thermal electric piping and steam generators is presented. The mechanical properties data generation is evaluated.

S. Majumdar

1979-01-01

127

Development of a portable thermophotovoltaic power generator  

NASA Astrophysics Data System (ADS)

A 150 Watt thermophotovoltaic (TPV) power generator is being developed. The technical approach taken in the design focused on optimizing the integrated performance of the primary subsystems in order to yield high energy conversion efficiency and cost effectiveness. An important aspect of the approach is the use of a selective emitter radiating to a bandgap matched photovoltaic array to minimize thermal and optical recuperation requirements, as well as the non-recoverable heat losses. For the initial prototype system, fibrous ytterbia emitters radiating in a band centered at 980 nm are matched with high efficiency silicon photoconverters. The integrated system includes a dielectric stack filter for optical energy recovery and a ceramic recuperator for thermal energy recovery. The system has been operated with air preheat temperatures up to 1350K. The design of the system and development status are presented.

Becker, Frederick E.; Doyle, Edward F.; Shukla, Kailash

1997-03-01

128

Storage systems for solar thermal power  

NASA Technical Reports Server (NTRS)

A major constraint to the evolution of solar thermal power systems is the need to provide continuous operation during periods of solar outage. A number of high temperature thermal energy storage technologies which have the potential to meet this need are currently under development. The development status is reviewed of some thermal energy storage technologies specifically oriented towards providing diurnal heat storage for solar central power systems and solar total energy systems. These technologies include sensible heat storage in caverns and latent heat storage using both active and passive heat exchange processes. In addition, selected thermal storage concepts which appear promising to a variety of advanced solar thermal system applications are discussed.

Calogeras, J. E.; Gordon, L. H.

1978-01-01

129

Thermoelectric cooling and power generation  

PubMed

In a typical thermoelectric device, a junction is formed from two different conducting materials, one containing positive charge carriers (holes) and the other negative charge carriers (electrons). When an electric current is passed in the appropriate direction through the junction, both types of charge carriers move away from the junction and convey heat away, thus cooling the junction. Similarly, a heat source at the junction causes carriers to flow away from the junction, making an electrical generator. Such devices have the advantage of containing no moving parts, but low efficiencies have limited their use to specialty applications, such as cooling laser diodes. The principles of thermoelectric devices are reviewed and strategies for increasing the efficiency of novel materials are explored. Improved materials would not only help to cool advanced electronics but could also provide energy benefits in refrigeration and when using waste heat to generate electrical power. PMID:10426986

DiSalvo

1999-07-30

130

Wind wheel electric power generator  

NASA Technical Reports Server (NTRS)

Wind wheel electric power generator apparatus includes a housing rotatably mounted upon a vertical support column. Primary and auxiliary funnel-type, venturi ducts are fixed onto the housing for capturing wind currents and conducting to a bladed wheel adapted to be operatively connected with the generator apparatus. Additional air flows are also conducted onto the bladed wheel; all of the air flows positively effecting rotation of the wheel in a cumulative manner. The auxiliary ducts are disposed at an acute angle with respect to the longitudinal axis of the housing, and this feature, together with the rotatability of the housing and the ducts, permits capture of wind currents within a variable directional range.

Kaufman, J. W. (inventor)

1980-01-01

131

Windmill having thermal and electric power output  

SciTech Connect

A windmill is described which has thermal and electric power output and includes windmill blades rotatably mounted and connected to a speed increaser mechanism of gears and shafts and a centrifugal compressor connected to the windmill thru the speed increaser to be driven by virtue of the wind applied to the blades of the windmill itself. A directional control is connected to the windmill head to have the windmill blades face into the wind, as desired. The compressor is connected to an insulated heat storage tank which contains storage material, such as brick, and the compressor discharge velocity and pressure difference are converted to heat, and the compressor fluid is returned to the compressor thru a screen which protects the compressor, and there is a flow control which automatically compensates for changes in density of the circulated air or compressor fluid. Also, a gas turbine generator can be connected with the compressor to be driven thereby, and electric elements could be connected with the generator for producing electricity. Two other embodiments show an impeller type of air brake and a valve and a heat-sensitive control, for generating heat or power.

Kenney, C.E.

1980-11-25

132

Future Photovoltaic Power Generation for Space-Based Power Utilities  

Microsoft Academic Search

A recent NASA program, Space Solar Power Exploratory Research and Technology (SERT), investigated the technologies needed to provide cost-competitive ground baseload electrical power from space based solar energy conversion. This goal mandated low cost, light weight gigawatt (GW) power generation. Investment in solar power generation technologies would also benefit high power military, commercial and science missions. These missions are generally

S. Bailey; G. Landis; R. Raffaelle; A. Hepp

2002-01-01

133

Control of Pollution from the Generation of Nuclear Power  

Microsoft Academic Search

Since the early days of the Manhattan District, there has been concern over potential pollution from the manufacture of atomic weapons and the generation of nuclear power. With time it has become obvious that the nuclear power plants themselves are not important sources of radioactive wastes, although they can be responsible for thermal pollution, as are conventional fossil fuel burning

WALLACE DE LAGUNA

1969-01-01

134

Distributed generation: remote power systems with advanced storage technologies  

Microsoft Academic Search

The paper discusses derived from an earlier hypothetical study of remote villiages. It considers the policy implications for communities who have their own local power resources rather than those distributed through transmission from distant sources such as dams, coal power plants or even renewables generation from wind farms, solar thermal or other resources. The issues today, post 911 and the

Woodrow Clark; William Isherwood

2004-01-01

135

Thermal management of large pulsed power systems  

NASA Astrophysics Data System (ADS)

Current thermal control technology is reviewed and limitations assessed compared to a typical high pulse power application. Thermal management is a significant weight factor (approximately 50%) of even medium power systems which points to a large potential payback from innovative techniques. Thermal research is recommended in the areas of concentrating and thermovoltaic solar arrays, two phase heat transport loops, direct contact heat exchangers and advanced radiator systems. Air Force space power trends indicate requirements for systems with 10 to 200 KW average power with pulse/average power ratios of 10/1 to 1000/1. Thermal system definition is complicated by the variety of possible power systems although solar and nuclear (Brayton and Thermionic) appear to be the leading candidates.

Haslett, B.

136

Power Generation: The Next 30 Years  

ERIC Educational Resources Information Center

Discusses pollution problems associated with power production. Estimates power consumption in the 1980's and the availability of fossil and nuclear fuel resources. Emphasizes needed research on air pollution, nuclear pollution, and thermal pollution. (EB)

Holcomb, Robert W.

1970-01-01

137

Concerns generated by islanding [electric power generation  

Microsoft Academic Search

The purpose of this article is to discuss islanding operation and to provide end-users with items to consider when determining distributed generation plant and equipment design requirements. Islanding is operating an electric generating plant without an external voltage and frequency reference. Operating in parallel is the opposite of islanding. This article attempts to describe the valid concerns that grid operators

P. L. Villenueve

2004-01-01

138

Active thermal control of power electronics modules  

Microsoft Academic Search

Active thermal control techniques make it feasible to regulate the steady state and transient thermal-mechanical stress in power electronic modules for applications such as motor drives. On-line junction temperature estimation and manipulation of the switching frequency and current limit to regulate the losses, are used to prevent over-temperature and power cycling failures in IGBT power modules. The techniques developed in

D. A. Murdock; J. E. Ramos; J. J. Connors; R. D. Lorenz

2003-01-01

139

A contactless power supply for photovoltaic power generation system  

Microsoft Academic Search

Among the alternative energy sources, the solar energy is recognized as an important energy source and its application is increasing. Especially in future, the hybrid solar energy generation system with battery and fuel cell will be widely used as an independent distributed power generation system. In this paper, a solar power hybrid home generation system using a contactless power supply

Eun-Soo Kim; Sung-In Kang; Kwang-Ho Yoon; Yoon-Ho Kim

2008-01-01

140

Low cost space power generation  

NASA Technical Reports Server (NTRS)

The success of this study has given a method of fabricating durable copolymer films without size limitations. Previously, only compression molded samples were durable enough to generate electrical energy. The strengthened specimens are very long lived materials. The lifetime was enhanced at least a factor of 1,300 in full pyroelectric conversion cycle experiments compared with extruded, non-strengthened film. The new techniques proved so successful that the lifetime of the resultant copolymer samples was not fully characterized. The lifetime of these new materials is so long that accelerated tests were devised to probe their durability. After a total of more than 67 million high voltage electrical cycles at 100 C, the electrical properties of a copolymer sample remained stable. The test was terminated without any detectable degradation to allow for other experiments. One must be cautious in extrapolating to power cycle performance, but 67 million electrical cycles correspond to 2 years of pyroelectric cycling at 1 Hz. In another series of experiments at reduced temperature and electrical stress, a specimen survived over one-third of a billion electrical cycles during nearly three months of continuous testing. The radiation-limited lifetimes of the copolymer were shown to range from several years to millions of years for most earth orbits. Thus, the pyroelectric copolymer has become a strong candidate for serious consideration for future spacecraft power supplies.

Olsen, Randall B.

1991-01-01

141

A single-spin-current thermal generator  

NASA Astrophysics Data System (ADS)

We theoretically propose a single-spin-current thermal generator consisting of a Rashba quantum dot (QD), one hot electrode and two cold electrodes. The Rashba QD is directly coupled to the three electrodes, and there exists a bridge channel between the two cold electrodes. Our results show the QD device can be used to generate pure spin-up or spin-down currents in cold electrodes in the absence of bias voltages and magnetic materials. The underlying reason is a cooperative effect of the spin-dependent quantum interference effects originating from Rashba spin-orbit interaction in the QD and temperature gradients among the three electrodes. The working conditions for the single-spin-current thermal generator are also clearly presented. Moreover, we also find that the device can be converted from n-type to p-type or vice versa by a gate voltage.

Liu, Y. S.; Yang, X. F.; Hong, X. K.; Chi, F.

2012-07-01

142

Dispersed solar thermal generation employing parabolic dish-electric transport with field modulated generator systems  

NASA Technical Reports Server (NTRS)

This paper discusses the application of field modulated generator systems (FMGS) to dispersed solar-thermal-electric generation from a parabolic dish field with electric transport. Each solar generation unit is rated at 15 kWe and the power generated by an array of such units is electrically collected for insertion into an existing utility grid. Such an approach appears to be most suitable when the heat engine rotational speeds are high (greater than 6000 r/min) and, in particular, if they are operated in the variable speed mode and if utility-grade a.c. is required for direct insertion into the grid without an intermediate electric energy storage and reconversion system. Predictions of overall efficiencies based on conservative efficiency figures for the FMGS are in the range of 25 per cent and should be encouraging to those involved in the development of cost-effective dispersed solar thermal power systems.

Ramakumar, R.; Bahrami, K.

1981-01-01

143

Dispersed solar thermal generation employing parabolic dish-electric transport with field modulated generator systems  

NASA Astrophysics Data System (ADS)

This paper discusses the application of field modulated generator systems (FMGS) to dispersed solar-thermal-electric generation from a parabolic dish field with electric transport. Each solar generation unit is rated at 15 kWe and the power generated by an array of such units is electrically collected for insertion into an existing utility grid. Such an approach appears to be most suitable when the heat engine rotational speeds are high (greater than 6000 r/min) and, in particular, if they are operated in the variable speed mode and if utility-grade a.c. is required for direct insertion into the grid without an intermediate electric energy storage and reconversion system. Predictions of overall efficiencies based on conservative efficiency figures for the FMGS are in the range of 25 per cent and should be encouraging to those involved in the development of cost-effective dispersed solar thermal power systems.

Ramakumar, R.; Bahrami, K.

144

Parabolic Trough Solar Thermal Electric Power Plants  

SciTech Connect

Although many solar technologies have been demonstrated, parabolic trough solar thermal electric power plant technology represents one of the major renewable energy success stories of the last two decades.

Not Available

2003-06-01

145

Power Smoothing and MPPT for Grid-connected Wind Power Generation with Doubly Fed Induction Generator  

Microsoft Academic Search

Recently, doubly fed induction generator (DFIG) and synchronous generator are mostly applied for wind power generation, and variable speed control and power factor control are executed for high efficiently for wind energy capture and high quality for power system voltage. In variable speed control, a wind speed or a generator speed is used for maximum power point tracking. However, performances

Takaaki Kai; Yuji Tanaka; Hirotoshi Kaneda; Daichi Kobayashi; Akio Tanaka

2008-01-01

146

Power generation of a thermoelectric generator with phase change materials  

NASA Astrophysics Data System (ADS)

In this paper, a thermoelectric generator that embeds phase change materials for wasted heat energy harvesting is proposed. The proposed thermoelectric generator embeds phase change materials in its device structure. The phase change materials store large amounts of heat energy using the latent heat of fusion. When the heat source contacts the thermoelectric generator, dissipated heat from the heat source is stored in the phase change materials. When the heat source is removed from the thermoelectric generator, the output power of the thermoelectric generator slowly decreases, while the output power of conventional thermoelectric generators decreases rapidly without the heat source. The additional air layer in the proposed thermoelectric generator disturbs the heat dissipation from the phase change materials, so the thermoelectric generator can maintain the power generation for longer without a heat source. The experimental results for the thermoelectric generator fabricated clearly show the latent heat effect of the phase change materials and the embedded air layer.

Jo, Sung-Eun; Kim, Myoung-Soo; Kim, Min-Ki; Kim, Yong-Jun

2013-11-01

147

Storage systems for solar thermal power  

NASA Technical Reports Server (NTRS)

The development status is reviewed of some thermal energy storage technologies specifically oriented towards providing diurnal heat storage for solar central power systems and solar total energy systems. These technologies include sensible heat storage in caverns and latent heat storage using both active and passive heat exchange processes. In addition, selected thermal storage concepts which appear promising to a variety of advanced solar thermal system applications are discussed.

Calogeras, J. E.; Gordon, L. H.

1978-01-01

148

Thermoelectric Analogy Thermal Models of Power Transformers  

Microsoft Academic Search

\\u000a This chapter first presents the conventional thermal models adopted in the IEC and the IEEE regulations for oil-immersed power\\u000a transformers, including steady-state models, transient-state models and hot-spot temperature rise models. In order to improve\\u000a the calculation accuracy of transformer thermal models, two thermoelectric analogy thermal models have been developed, which\\u000a are rooted on the principles of heat exchange and electric

W. H. Tang; Q. H. Wu

149

Storage Systems for Solar Thermal Power.  

National Technical Information Service (NTIS)

A major constraint to the evolution of solar thermal power systems is the need to provide continuous operation during periods of solar outage. A number of high temperature thermal energy storage technologies which have the potential to meet this need are ...

J. E. Calogeras L. H. Gordon

1978-01-01

150

Stability of open-cycle MHD generation system connected to power transmission line  

Microsoft Academic Search

The stability of the binary combined system of an MHD generator and a synchronous generator, including inverter and power transmission system, is studied numerically. The binary combined power generation system is a pilot plant scale with thermal input of about 110MW and consists of a MHD generator as a topping cycle and a steam turbine generator as a bottoming cycle.

Nobuhiko Hayanose; Yoshitaka Inui; Motoo Ishikawa; Juro Umoto

1998-01-01

151

Thermal Power Dissipation of Solid State Electric Power Controllers.  

National Technical Information Service (NTIS)

A brief study was performed in thermal parameters associated with solid-state load controllers. It was found impractical, with the present state of the art, to realize miniaturization in enclosures for power transistors. Exposed areas, component interface...

C. Sears H. Brown

1970-01-01

152

MHD pulsed power generation and applications  

Microsoft Academic Search

We have been proposing to use non-equilibrium MHD generator as a pulsed power supply for various applications. This system has inherent advantages of high power density, high reliability and high durability compared with combustion driven type equilibrium MHD generator. For this system, Non-equilibrium Plasma Generator (NPG), where light metal combustion with pure oxygen heat up working medium of inert gas,

N. Harada

2001-01-01

153

Electronic power generators for ultrasonic frequencies  

NASA Technical Reports Server (NTRS)

The design and construction of an ultrasonic frequency electronic power generator are discussed. The principle design elements of the generator are illustrated. The generator provides an inductive load with an output power of two kilowatts and a variable output frequency in the fifteen to thirty KiloHertz range. The method of conducting the tests and the results obtained with selected materials are analyzed.

Ciovica, D.

1974-01-01

154

Power Generation Capabilities of Tie Tube Assemblies  

NASA Astrophysics Data System (ADS)

Second generation nuclear thermal rocket engine designs, employing solid core reactors and expander engine cycles, generally rely on some form of nuclear-driven heater to supply the major portion of thermal energy required to preheat the turbine-drive gases. If adequate heat transfer occurs, not only will efficiency-enhancing turbine-inlet temperatures be realized, but sufficient energy will be available to enable engine operation at chamber pressures ranging to at least 2,000 psia. For the case of reactor cores employing prismatic fuel elements, the utilization of tie tube assemblies, as first employed in the core-support subsystem of the Phoebus II reactor, can provide the basis of an array of propellant (hydrogen) preheaters that offer an ample supply of energy and temperature to enable candidate expander engine cycles over a wide range of operating parameters, without reducing the total enthalpy of the core-exit gas and its attendant effect on specific impulse. By modifying the tie tube design concept set forth in LASL's Nuclear Rocket Engine definition study, a powerful, weight and packaging-effective, preheater assembly can be realized. The design features of these tie tube assemblies reflect their functional objectives, core criticality considerations, and space constraints. Since the core pressure and inertial mass loads are carried by these assemblies, the structural tubular element(s) also provide coolant passage(s) for the hydrogen. The transfer of heat to the coolant surfaces is controlled by the effective thermal conductivity of the filler structure and ``insulating sleeves,'' which surround the tubular elements and are in controlled thermal contact with the surrounding core fuel elements. An option exists to further increase the transported heat to the coolant walls by the selective loading of the filler structure, ``insulating sleeves,'' and the moderator annular element with fissionable material.

Gunn, Stanley V.; Hedstrom, James; Hundal, Rolv

1994-07-01

155

High Power Rechargeable Thermal Battery.  

National Technical Information Service (NTIS)

Report developed under STTR contract; a proof of concept for a portable, rechargeable thermal battery (RTB). Including a superinsulated case, a lightweight (10 lb) RTB can provide 250W for 2-6h at 140 Wh/kg with days of activation between recharging. It c...

T. D. Kaun

1997-01-01

156

Electrical power generation by mechanically modulating electrical double layers.  

PubMed

Since Michael Faraday and Joseph Henry made their great discovery of electromagnetic induction, there have been continuous developments in electrical power generation. Most people today get electricity from thermal, hydroelectric, or nuclear power generation systems, which use this electromagnetic induction phenomenon. Here we propose a new method for electrical power generation, without using electromagnetic induction, by mechanically modulating the electrical double layers at the interfacial areas of a water bridge between two conducting plates. We find that when the height of the water bridge is mechanically modulated, the electrical double layer capacitors formed on the two interfacial areas are continuously charged and discharged at different phases from each other, thus generating an AC electric current across the plates. We use a resistor-capacitor circuit model to explain the results of this experiment. This observation could be useful for constructing a micro-fluidic power generation system in the near future. PMID:23403587

Moon, Jong Kyun; Jeong, Jaeki; Lee, Dongyun; Pak, Hyuk Kyu

2013-01-01

157

MHD generator scaling analysis for baseload commercial power plants  

SciTech Connect

MHD generator channel scaling analyses have been performed to definitize the effect of generator size and oxygen enrichment on channel performance. These studies have shown that MHD generator channels can be designed to operate efficiently over the range of 250 to 2135 thermal megawatts. The optimum design conditions for each of the thermal inputs were established by investigating various combinations of electrical load parameters, pressure ratios, magnetic field profiles, and channel lengths. These results provide design flexibility for the baseload combined cycle MHD/steam power plant.

Swallom, D.W.; Pian, C.C.P.

1982-01-01

158

Equilibrium and kinetic studies of in situ generation of ammonia from urea in a batch reactor for flue gas conditioning of thermal power plants  

SciTech Connect

Ammonia has long been known to be useful in the treatment of flue/tail/stack gases from industrial furnaces, incinerators, and electric power generation industries. In this study, urea hydrolysis for production of ammonia, in different application areas that require safe use of ammonia at in situ condition, was investigated in a batch reactor. The equilibrium and kinetic study of urea hydrolysis was done in a batch reactor at reaction pressure to investigate the effect of reaction temperature, initial feed concentration, and time on ammonia production. This study reveals that conversion increases exponentially with an increase in temperature but with increases in initial feed concentration of urea the conversion decreases marginally. Further, the effect of time on conversion has also been studied; it was found that conversion increases with increase in time. Using collision theory, the temperature dependency of forward rate constant developed from which activation energy of the reaction and the frequency factor has been calculated. The activation energy and frequency factor of urea hydrolysis reaction at atmospheric pressure was found to be 73.6 kJ/mol and 2.89 x 10{sup 7} min{sup -1}, respectively.

Sahu, J.N.; Patwardhan, A.V.; Meikap, B.C. [Indian Institute of Technology, Kharagpur (India). Dept. of Chemical Engineering

2009-03-15

159

Environment Friendly Coal Based Power Generation in Pakistan  

NASA Astrophysics Data System (ADS)

The main emphasis of this paper is on the engineering economics and design developments in the field of thermal power generation in Pakistan. Pakistan is rich with coal fields but is making no use of this available natural resource to fulfil its energy demands. The shortage of power is getting worst day by day and to align with the power requirements, Pakistan needs to add 2000 MW each year to national grid. With the increasing prices of natural gas and oil, Pakistan should consider coal, the abundantly available natural resource, as an alternate fuel for its new power plants to overcome the power crises.

Qureshi, S. A.; Javed, M. Adnan

2010-06-01

160

The small community solar thermal power experiment  

NASA Technical Reports Server (NTRS)

the objectives and current status of the Small Community Solar Thermal Power Experiment are discussed. The adjustments in programs goals made in response to the changing emphasis in the area of solar energy in national policy are addressed. Planned fabrication and testing activities for the test bed concentrator, power conversion assembly, and control system are outlined.

Kiceniuk, T.

1982-01-01

161

Solar Thermal Power Systems parabolic dish project  

NASA Technical Reports Server (NTRS)

The status of the Solar Thermal Power Systems Project for FY 1980 is summarized. Included is: a discussion of the project's goals, program structure, and progress in parabolic dish technology. Analyses and test results of concentrators, receivers, and power converters are discussed. Progress toward the objectives of technology feasibility, technology readiness, system feasibility, and system readiness are covered.

Truscello, V. C.

1981-01-01

162

Pv-Thermal Solar Power Assembly  

DOEpatents

A flexible solar power assembly includes a flexible photovoltaic device attached to a flexible thermal solar collector. The solar power assembly can be rolled up for transport and then unrolled for installation on a surface, such as the roof or side wall of a building or other structure, by use of adhesive and/or other types of fasteners.

Ansley, Jeffrey H. (El Cerrito, CA); Botkin, Jonathan D. (El Cerrito, CA); Dinwoodie, Thomas L. (Piedmont, CA)

2001-10-02

163

Power-thermal analysis of multimedia applications  

Microsoft Academic Search

Multimedia applications become one of the most popular applications on mobile devices. An important current problem of multimedia applications running on battery powered devices is their power intensive profile, which entails an increase of device heat dissipation. Due to the intensive computational nature of multimedia applications and due to the resource limitations of mobile devices, current thermal management techniques are

Marius Marcu; Camil Milos; Dacian Tudor

2010-01-01

164

Power semiconductor device with negative thermal feedback  

NASA Technical Reports Server (NTRS)

Composite power semiconductor avoids second breakdown and provides stable operation. It consists of an array of parallel-connected integrated circuits fabricated in a single chip. The output power device and associated low-level amplifier are closely coupled thermally, so that they have a predetermined temperature relationship.

Borky, J. M.; Thornton, R. D.

1970-01-01

165

Space Station Freedom solar dynamic power generation  

NASA Technical Reports Server (NTRS)

Viewgraphs on Space Station Freedom solar dynamic power generation are presented. Topics covered include: prime contract activity; key solar dynamic power module requirements; solar dynamic heat receiver technology; and solar concentrator advanced development.

Springer, T.; Friefeld, Jerry M.

1990-01-01

166

Power-maximizing electrical energy generation system  

US Patent & Trademark Office Database

An electrical energy generation system comprising: a plurality of photovoltaic generators connected in parallel and connected to a common load via respective DC voltage converters; and a regulator configured to vary the transconductances of said respective voltage converters to maximize the power generated by said current generators; wherein: said generators are also connected to a common input of an additional voltage converter the output of which is connected to said common load; and said regulator is also configured to vary the transconductance of said additional voltage converter to maximize the power generated by said current generators.

2010-08-03

167

Pulse power applications of flux compression generators  

SciTech Connect

Characteristics are presented for two different types of explosive driven flux compression generators and a megavolt pulse transformer. Status reports are given for rail gun and plasma focus programs for which the generators serve as power sources.

Fowler, C.M.; Caird, R.S.; Erickson, D.J.; Freeman, B.L.

1981-01-01

168

Thermoelectric power generator with intermediate loop  

DOEpatents

A thermoelectric power generator is disclosed for use to generate electrical power from heat, typically waste heat. An intermediate heat transfer loop forms a part of the system to permit added control and adjustability in the system. This allows the thermoelectric power generator to more effectively and efficiently generate power in the face of dynamically varying temperatures and heat flux conditions, such as where the heat source is the exhaust of an automobile, or any other heat source with dynamic temperature and heat flux conditions.

Bel,; Lon E. (Altadena, CA); Crane, Douglas Todd (Pasadena, CA)

2009-10-27

169

Solar driven liquid metal MHD power generator  

SciTech Connect

A method for solar electric power generation in space is described. A solar energy collector focuses solar energy onto a solar oven which is attached to a mixer which in turn is attached to the channel of a MHD generator. Gas enters the oven and a liquid metal enters the mixer. The gas/liquid metal mixture is heated by the collected solar energy and moves through the MHD generator thereby generating electrical power. The mixture is then separated and recycled. NASA

Lee, J.H.; Hohl, F.

1981-05-01

170

Uninterrupted power supply using slip-power recovery induction generator  

Microsoft Academic Search

This paper describes an uninterrupted power supply (UPS) using a slip-power recovery induction generator with a battery-inverter system. This UPS has the following merits. The induction generator is started and accelerated quickly without load, since the UPS function is realized by a battery-inverter system. Once the generator is accelerated to a substantial speed, connection to the power system is performed

N. Kimura; K. Taniguchi

1995-01-01

171

Integrated engine generator for aircraft secondary power  

NASA Technical Reports Server (NTRS)

An integrated engine-generator for aircraft secondary power generation is described. The concept consists of an electric generator located inside a turbojet or turbofan engine and both concentric with and driven by one of the main engine shafts. The electric power conversion equipment and generator controls are located in the aircraft. When properly rated, the generator serves as an engine starter as well as a source of electric power. This configuration reduces or eliminates the need for an external gear box on the engine and permits reduction in the nacelle diameter.

Secunde, R. R.

1972-01-01

172

Solar thermal power systems point-focusing thermal and electric applications projects. Volume 1: Executive summary  

NASA Technical Reports Server (NTRS)

The activities of the Point-Focusing Thermal and Electric Applications (PETEA) project for the fiscal year 1979 are summarized. The main thrust of the PFTEA Project, the small community solar thermal power experiment, was completed. Concept definition studies included a small central receiver approach, a point-focusing distributed receiver system with central power generation, and a point-focusing distributed receiver concept with distributed power generation. The first experiment in the Isolated Application Series was initiated. Planning for the third engineering experiment series, which addresses the industrial market sector, was also initiated. In addition to the experiment-related activities, several contracts to industry were let and studies were conducted to explore the market potential for point-focusing distributed receiver (PFDR) systems. System analysis studies were completed that looked at PFDR technology relative to other small power system technology candidates for the utility market sector.

Marriott, A.

1980-01-01

173

A dish-Stirling solar-thermal power system  

NASA Technical Reports Server (NTRS)

This paper presents results of a preliminary design/economic study of a first-generation point focusing distributed receiver solar-thermal electric system optimized for application to industrial and small community power plants at power levels up to 10 MWe. Power conversion is provided by small Stirling cycle engines mounted at the focus of paraboloidal solar concentrators. The output of multiple power modules (concentrator, receiver, engine, and electric generator) is collected by means of a conventional electrical system and interfaced with a utility grid. Based on the United Stirling P-75 engine, a 1 MWe system employing mass-produced components (100,000 modules/year) could produce electricity at costs competitive with those projected for electricity generated by more conventional means, e.g. with fossil fuels.

Pons, R. L.; Clark, T. B.

1980-01-01

174

Explosive pulsed electric power generation  

Microsoft Academic Search

A 5-year Multidisciplinary Research Initiative (MURI) program on generating high energy electric pulses from explosive generators is funded by the office of the Director of Defense Research and Engineering and monitored by the Air Force Office of Scientific Research. The program involves Texas Tech University (lead university), the University of Missouri at Rolla, Texas A&M University and The University of

M. Kristiansen; J. Gregor

2001-01-01

175

Electrical power generation and distribution system  

Microsoft Academic Search

Problems associated with moving fuel from remote sources to large centralized power generation plants are avoided with an economical system for collecting power from small stations located near the scattered, remote fuel sites. To avoid a need for many massive, costly transformers, a plurality of relatively low voltage generating stations are connected in series to cumulatively produce the high voltage

Jeppson

1977-01-01

176

Coal gasification for advanced power generation  

Microsoft Academic Search

This paper provides a review of the development and deployment of coal based gasification technologies for power generation. The global status of gasification is described covering the various process and technology options. The use of gasification for power generation is then highlighted including the advantages and disadvantages of this means for coal utilisation. The R, D & D needs and

Andrew J. Minchener

2005-01-01

177

Performance analysis of solar thermal power systems  

NASA Astrophysics Data System (ADS)

Methods of analyzing and predicting the performance of solar thermal power plants for electric applications are discussed, and insight provided into the major energy loss mechanisms for solar thermal systems. The efficiency of each component in a solar thermal plant is discussed as are the plant parasitic losses and plant availability. This is followed by a discussion of the computer simulation which is needed to derive reasonable projections of component annual efficiencies and parasitic losses. Finally, plant design considerations and annual system performance estimates are made.

Williams, T. A.; Dirks, J. A.

1987-04-01

178

Small spacecraft power and thermal subsystems  

NASA Astrophysics Data System (ADS)

This white paper provides a general guide to the conceptual design of satellite power and thermal control subsystems with special emphasis on the unique design aspects associated with small satellites. The operating principles of these technologies are explained and performance characteristics of current and projected components are provided. A tutorial is presented on the design process for both power and thermal subsystems, with emphasis on unique issues relevant to small satellites. The ability of existing technology to meet future performance requirements is discussed. Conclusions and observations are presented that stress cost-effective, high-performance design solutions.

Eakman, D.; Lambeck, R.; Mackowski, M.; Slifer, L., Jr.

1994-12-01

179

Small spacecraft power and thermal subsystems  

NASA Technical Reports Server (NTRS)

This white paper provides a general guide to the conceptual design of satellite power and thermal control subsystems with special emphasis on the unique design aspects associated with small satellites. The operating principles of these technologies are explained and performance characteristics of current and projected components are provided. A tutorial is presented on the design process for both power and thermal subsystems, with emphasis on unique issues relevant to small satellites. The ability of existing technology to meet future performance requirements is discussed. Conclusions and observations are presented that stress cost-effective, high-performance design solutions.

Eakman, D.; Lambeck, R.; Mackowski, M.; Slifer, L., Jr.

1994-01-01

180

Ground Power Thermoelectric Generator Module.  

National Technical Information Service (NTIS)

The report describes the recent work on high power density thermoelectric elements and encompasses thermoelectric design and analysis, element development and fabrication and element operations. Sixty-two elements were fabricated and tested and 59 were an...

G. Zindler R. Magladry

1967-01-01

181

Ground Power Thermoelectric Generator Investigation.  

National Technical Information Service (NTIS)

This report describes the development work on high power density thermoelectric elements and encompasses thermoelectric element design and analysis, element development and fabrication, and element operation. The element design and analysis portion of the...

R. Magladry T. H. Cox L. J. Gagola H. M. Kreitz M. N. Ross

1966-01-01

182

High-power microwave pulse generator  

NASA Astrophysics Data System (ADS)

An inexpensive alternative to commercial high-power microwave-pulse generators is described. The present high-power microwave-pulse generator utilizes a surplus MIT model-3 Mark-II hard-tube modulator and 2J51 magnetron. The basic design and technical details of the pulse generator are presented. The pulse generator is designed to produce 8.5-9.6 GHz pulses with pulse lengths ranging from 2 to 4 microns with a nominal power output of 20 kW and a maximum duty cycle of 0.001.

White, G. O.; Chen, L.; Patton, C. E.; Tinkoff, R. L.

1992-05-01

183

Power Control of New Wind Power Generation System with Induction Generator Excited by Voltage Source Converter  

NASA Astrophysics Data System (ADS)

This paper investigates advantages of new combination of the induction generator for wind power and the power electronic equipment. Induction generator is popularly used for the wind power generation. The disadvantage of it is impossible to generate power at the lower rotor speed than the synchronous speed. To compensate this disadvantage, expensive synchronous generator with the permanent magnets is sometimes used. In proposed scheme, the diode rectifier is used to convert the real power from the induction generator to the intermediate dc voltage, while only the reactive power necessary to excite the induction generator is supplied from the voltage source converter (VSC). This means that the rating of the expensive VSC is minimized and total cost of the wind power generation system is decreased compared to the system with synchronous generator. Simulation study to investigate the control strategy of proposed system is performed. The results show the reduction of the VSC rating is prospective.

Morizane, Toshimitsu; Kimura, Noriyuki; Taniguchi, Katsunori

184

LPGC. Levelized Power Generation Cost Codes  

Microsoft Academic Search

LPGC is a set of nine microcomputer programs for estimating power generation costs for large steam-electric power plants. These programs permit rapid evaluation using various sets of economic and technical ground rules. The levelized power generation costs calculated may be used to compare the relative economics of nuclear and coal-fired plants based on life-cycle costs. Cost calculations include capital investment

J. J. Coen; J. G. Delene

1989-01-01

185

Review of Microscale Magnetic Power Generation  

Microsoft Academic Search

This paper discusses the history, current state of the art, and ongoing challenges for compact (less than a few cubic centimeters) magnetic power generation systems in the microwatts to tens of watts power range. These systems are of great interest for powering sensor networks, robotics, wireless communication systems, and other portable electronics. The paper considers the following topics. 1) The

David P. Arnold

2007-01-01

186

Thermoelectric power generation for battery charging  

Microsoft Academic Search

Thermoelectric generators use the Seebeck effect to produce electrical power from a temperature difference caused by heat energy flow. In this paper the principle of using thermoelectrically converted heat energy for powering portable electronic equipment or charging its battery has been investigated for a lap-top computer. The thermoelectric battery charger developed, consists of a thermoelectric converter system, powered from butane

Mahmudur Rahman; Roger Shuttleworth

1995-01-01

187

Improving the power quality performance for distributed power generation  

Microsoft Academic Search

The main aim of this paper is to analysis and improve the power quality (voltage sag, swell and harmonics) performance of smart grid connected inverter used in distributed generation. The structure of the designed controller consists of outer power with harmonic control loop, middle voltage control loop and inner current control loop for real and reactive power control in dq

R. Muralekrishnen; P. Sivakumar

2012-01-01

188

MHD generators in power production  

SciTech Connect

This paper reports on coalfired MHD steam combined-cycle power plants which offer significant improvements in overall plant efficiency as well as reduced environmental emissions. Development is currently in the proof-of-concept stage, with commercial plant retrofits under serious study.

Chapman, J.N.; Johanson, N.R. (Univ. of Tennessee, Space Inst., Tullahoma, TN (US))

1991-09-01

189

MHD generators in power production  

Microsoft Academic Search

This paper reports on coalfired MHD steam combined-cycle power plants which offer significant improvements in overall plant efficiency as well as reduced environmental emissions. Development is currently in the proof-of-concept stage, with commercial plant retrofits under serious study.

J. N. Chapman; N. R. Johanson

1991-01-01

190

Gigawatt power electron beam generator  

SciTech Connect

In this paper, the design and constructional details of a short-pulse electron beam generator are presented highlighting some of the novel features of its operation. The diagnostic results of the electron beam, both in the diode and in the drift region, are described. A 60-ns duration 200 keV, 30 kA electron beam has been obtained.

Jain, K.K.; John, P.I.

1981-04-01

191

Solar Thermal Power Plants with Parabolic-Trough Collectors  

NASA Astrophysics Data System (ADS)

Parabolic-trough collectors (PTC) are solar concentrating devices suitable to work in the 150°C- 400°C temperature range. Power plants based on this type of solar collectors are a very efficient way to produce electricity with solar energy. At present, there are eight commercial solar plants (called SEGS-II, III,.. IX) producing electricity with parabolic-trough collectors and their total output power is 340 MW. Though all SEGS plants currently in operation use thermal oil as a heat transfer fluid between the solar field and the power block, direct steam generation (DSG) in the receiver tubes is a promising option to reduce the cost of electricity produced with parabolic- trough power plants. Most of technical uncertainties associated to the DSG technology were studied and solved in the DISS project and it is expected that this new technology will be commercially available in a short term. In Spain, the Royal Decree No. 436/204 (March 12th , 2004) has defined a premium of 0,18€/kWh for the electricity produced by solar thermal power plants, thus promoting the installation of solar thermal power plants up to a limit of 200 MW. Due to the current legal and financial framework defined in Spain, several projects to install commercial solar power plants with parabolic-trough collectors are currently underway.

Zarza, E.; Valenzuela, L.; León, J.

2004-12-01

192

The SAS-3 power and thermal systems  

NASA Technical Reports Server (NTRS)

Solar array configurations of the SAS-3 are described: a configuration with two sets of coplanar panels in the horizontal and two others in the vertical position, and two other configurations with either four horizontal or four vertical sets of panels. The nickel-cadmium battery of the power subsystem is described in detail, with emphasis on voltage limits and charge-discharge characteristics. The characteristic of 'solar-only' operation in the case of damage to the battery is discussed. The thermal subsystem of SAS-3 is considered, with discussions of thermal design criteria and the thermal environment. Temperature is controlled by using internal thermal louvers that regulate the rate at which the heat load from electronic equipment is transmitted to the outer surface for dumping to space.

Sullivan, R. M.; Hogrefe, A. F.; Brenza, P. T.

1975-01-01

193

solar thermal power systems advanced solar thermal technology project, advanced subsystems development  

NASA Technical Reports Server (NTRS)

The preliminary design for a prototype small (20 kWe) solar thermal electric generating unit was completed, consisting of several subsystems. The concentrator and the receiver collect solar energy and a thermal buffer storage with a transport system is used to provide a partially smoothed heat input to the Stirling engine. A fossil-fuel combustor is included in the receiver designs to permit operation with partial or no solar insolation (hybrid). The engine converts the heat input into mechanical action that powers a generator. To obtain electric power on a large scale, multiple solar modules will be required to operate in parallel. The small solar electric power plant used as a baseline design will provide electricity at remote sites and small communities.

1979-01-01

194

New low cost IGCC designs for competitive power generation  

SciTech Connect

Design studies of coal based 450 MW new IGCC power plants reveal their ability to compete in today's power generation market. Single train unit designs coupled with significant improvements in IGCC net output and efficiency have brought down the installed costs to the range of 850--1,000 $/kW and net thermal efficiency up to 43--47%. These improvements are shown to result from IGCC design configurations integrating new generation gas turbine combined cycles with High Pressure Texaco Gasification Technology and Elevated Pressure Air Separation Units.

Brdar, D.R.; Depuy, R.A.; Gulko, G.; Jandrisevits, M.; Paolino, J.

1999-07-01

195

A reagentless technology to prevent biofouling on the surfaces of equipment at nuclear and thermal power stations using generators of OH radicals and ozone  

NASA Astrophysics Data System (ADS)

We present the results obtained from the development and tests of a reagentless method to prevent biofouling in water cooling systems of equipment using generators of OH radicals and ozone constructed on the basis of impulse ultraviolet xenon lamps producing light with a wavelength of 172 nm.

Izyumov, S. V.; Shchekotov, E. Yu.; Shchekotov, D. E.; Krutskikh, D. A.

2011-07-01

196

Power Smoothing and MPPT for Grid-connected Wind Power Generation with Doubly Fed Induction Generator  

NASA Astrophysics Data System (ADS)

Recently, doubly fed induction generator (DFIG) and synchronous generator are mostly applied for wind power generation, and variable speed control and power factor control are executed for high efficiently for wind energy capture and high quality for power system voltage. In variable speed control, a wind speed or a generator speed is used for maximum power point tracking. However, performances of a wind generation power fluctuation due to wind speed variation have not yet investigated for those controls. The authors discuss power smoothing by those controls for the DFIG inter-connected to 6.6kV distribution line. The performances are verified using power system simulation software PSCAD/EMTDC for actual wind speed data and are examined from an approximate equation of wind generation power fluctuation for wind speed variation.

Kai, Takaaki; Tanaka, Yuji; Kaneda, Hirotoshi; Kobayashi, Daichi; Tanaka, Akio

197

Power Generation Capabilities of Tie Tube Assemblies  

Microsoft Academic Search

Second generation nuclear thermal rocket engine designs, employing solid core reactors and expander engine cycles, generally rely on some form of nuclear-driven heater to supply the major portion of thermal energy required to preheat the turbine-drive gases. If adequate heat transfer occurs, not only will efficiency-enhancing turbine-inlet temperatures be realized, but sufficient energy will be available to enable engine operation

Stanley V. Gunn; James Hedstrom; Rolv Hundal

1994-01-01

198

Electrical machines technology for aerospace power generators  

NASA Astrophysics Data System (ADS)

Electric power generators for aerospace and aircraft applications are now required to be more reliable. It is noted that the wound field synchronous generator has been the workhorse for producing 400-Hz AC electric power for many years. Substantial evolution has occurred over the years by replacing low-speed generators with the 24,000-rpm design. The quality of the AC waveform produced by the wound field generators is excellent, the excitation power requirement is low, and control of output power is easily accomplished under abnormal operating conditions. Other changing requirements include variety of power types, increased reliability, and higher speeds and temperatures. It is pointed out that wound field synchronous generators have limitations due to rotating windings and rotating rectifiers. Other options such as self-regulating permanent magnet generators, switched reluctance generators, reluctance generators, flux switches overcome these limitations. It is suggested that the selection from these options must be based on the specific requirements for a given application, evaluating overall system constraints such as weight, performance, and cost.

Vaidya, Jayant G.

199

Proceedings of the Fifth Parabolic Dish Solar Thermal Power Program  

NASA Technical Reports Server (NTRS)

The proceedings of the Fifth Parabolic Dish Solar Thermal Power Program Annual Review are presented. The results of activities within the Parabolic Dish Technology and Module/Systems Development element of the Department of Energy's Solar Thermal Energy Systems Program were emphasized. Among the topics discussed were: overall Project and Program aspects, Stirling and Brayton module development, concentrator and engine/receiver development along with associated hardware and test results; distributed systems operating experience; international parabolic dish development activities; and non-DOE-sponsored domestic dish activities. Solar electric generation was also addressed.

Lucas, J. W. (editor)

1984-01-01

200

Economic analysis of nuclear power generation.  

National Technical Information Service (NTIS)

The purpose of this study is to clarify the role of nuclear power generation under the circumstances of growing concerns about environmental impact and to help decision making in electricity sector. In this study, efforts are made to estimate electricity ...

Y. G. Lee H. M. Lee K. D. Song M. K. Lee S. S. Kim

1992-01-01

201

Power generation method including membrane separation  

DOEpatents

A method for generating electric power, such as at, or close to, natural gas fields. The method includes conditioning natural gas containing C.sub.3+ hydrocarbons and/or acid gas by means of a membrane separation step. This step creates a leaner, sweeter, drier gas, which is then used as combustion fuel to run a turbine, which is in turn used for power generation.

Lokhandwala, Kaaeid A. (Union City, CA)

2000-01-01

202

Heat Transfer Enhancement in Thermoelectric Power Generation  

Microsoft Academic Search

Heat transfer plays an important role in thermoelectric (TE) power generation because the higher the heat-transfer rate from the hot to the cold side of the TE material, the higher is the generation of electric power. However, high heat-transfer rate is difficult to achieve compactly when the hot and\\/or the cold sources are maintained by a flow of gas such

Shih-yung Hu

2009-01-01

203

Probabilistic production costing simulation of a thermal system with a pumped-storage power plant  

Microsoft Academic Search

The paper presents a model and two algorithms for the calculation of the additional pumping generation of thermal power plants and the discharging energy of a pumped-storage power plant in a thermal system. Both algorithms lead to the solution of a univariate global optimization problem. One of these problems provides an optimal result. The other is suboptimal, as it is

J. Hoffer

1995-01-01

204

Power electronics and alternative energy generation  

Microsoft Academic Search

Growth in alterative energy generation technologies and markets will have a major impact on the development of power electronics in the future. The paper discusses some of these implications, and outlines the technological and performance challenges for power electronic systems in alternative energy applications.

James P Lyons; Vlatko Vlatkovic

2004-01-01

205

Nuclear power generating station equipment qualification apparatus  

Microsoft Academic Search

This patent describes a nuclear power plant having an object piece of qualified equipment, an apparatus for monitoring the object piece of qualified equipment. It comprises: passive means for detecting a gamma ray does of radiation received by the object piece; means for determining a thermal history of the object piece; means for detecting neutron-induced fission; monitor blocks, the gamma

Fero

1991-01-01

206

Concepts for central solar electric power generation  

NASA Technical Reports Server (NTRS)

The investigation reported was conducted to select the best conceptual design of a power plant for the dynamic conversion of solar heat to electricity. Conversion of thermal energy to electricity was to be an accomplished with conventional turbomachinery. Questions of site selection are discussed along with solar energy collection systems, aspects of candidate system definition, and reference systems.

Kintigh, J. K.

1974-01-01

207

Solar driven liquid metal MHD power generator  

Microsoft Academic Search

A method for solar electric power generation in space is described. A solar energy collector focuses solar energy onto a solar oven which is attached to a mixer which in turn is attached to the channel of a MHD generator. Gas enters the oven and a liquid metal enters the mixer. The gas\\/liquid metal mixture is heated by the collected

J. H. Lee; F. Hohl

1981-01-01

208

Control of thermal therapies with moving power deposition field  

NASA Astrophysics Data System (ADS)

A thermal therapy feedback control approach to control thermal dose using a moving power deposition field is developed and evaluated using simulations. A normal tissue safety objective is incorporated in the controller design by imposing constraints on temperature elevations at selected normal tissue locations. The proposed control technique consists of two stages. The first stage uses a model-based sliding mode controller that dynamically generates an 'ideal' power deposition profile which is generally unrealizable with available heating modalities. Subsequently, in order to approximately realize this spatially distributed idealized power deposition, a constrained quadratic optimizer is implemented to compute intensities and dwell times for a set of pre-selected power deposition fields created by a scanned focused transducer. The dwell times for various power deposition profiles are dynamically generated online as opposed to the commonly employed a priori-decided heating strategies. Dynamic intensity and trajectory generation safeguards the treatment outcome against modelling uncertainties and unknown disturbances. The controller is designed to enforce simultaneous activation of multiple normal tissue temperature constraints by rapidly switching between various power deposition profiles. The hypothesis behind the controller design is that the simultaneous activation of multiple constraints substantially reduces treatment time without compromising normal tissue safety. The controller performance and robustness with respect to parameter uncertainties is evaluated using simulations. The results demonstrate that the proposed controller can successfully deliver the desired thermal dose to the target while maintaining the temperatures at the user-specified normal tissue locations at or below the maximum allowable values. Although demonstrated for the case of a scanned focused ultrasound transducer, the developed approach can be extended to other heating modalities with moving deposition fields, such as external and interstitial ultrasound phased arrays, multiple radiofrequency needle applicators and microwave antennae.

Arora, Dhiraj; Minor, Mark A.; Skliar, Mikhail; Roemer, Robert B.

2006-03-01

209

Solar driven liquid metal MHD power generator  

NASA Technical Reports Server (NTRS)

A solar energy collector focuses solar energy onto a solar oven which is attached to a mixer which in turn is attached to the channel of a MHD generator. Gas enters the oven and a liquid metal enters the mixer. The gas/liquid metal mixture is heated by the collected solar energy and moves through the MHD generator thereby generating electrical power. The mixture is then separated and recycled.

Lee, J. H.; Hohl, F. (inventors)

1983-01-01

210

Performances of AMBIORIX [pulsed power generator  

Microsoft Academic Search

AMBIORIX is a high pulsed power generator designed and built by the HPP team of Valduc CEA center in 1985. This generator is now located in CESTA, a center of CEA near Bordeaux (France). AMBIORIX is formed with a Marx generator (maximum energy storage=300 kJ), water coaxial and triaxial lines. Output parameters are: 0,5 ? impedance; 1.2 MV diode voltage;

Ph. Romary; P. Eyl; J. M. Angles

1995-01-01

211

45 GW Pulsed-Power Generator  

Microsoft Academic Search

The construction, and initial tests, of a 45 GW pulsed-power generator with an impedance of 2 Omega are presented. The generator can deliver a rectangular pulse of 300 kV with duration of 200 ns across a matched load. The generator is designed to be able to deliver a voltage of 500 kV into a 10 Omega unmatched load. Since the

A. Lindblom; A. Larsson; H. Bernhoff; M. Leijon

2007-01-01

212

Solar driven liquid metal mhd power generator  

SciTech Connect

A solar energy collector focuses solar energy onto a solar oven which is attached to a mixer which in turn is attached to the channel of a mhd generator. Gas enters the oven and a liquid metal enters the mixer. The gas/liquid metal mixture is heated by the collected solar energy and moves through the mhd generator thereby generating electrical power. The mixture is then separated and recycled.

Hohl, F.; Lee, J.H.

1983-06-14

213

Solar driven liquid metal MHD power generator  

NASA Astrophysics Data System (ADS)

A solar energy collector focuses solar energy onto a solar oven which is attached to a mixer which in turn is attached to the channel of a MHD generator. Gas enters the oven and a liquid metal enters the mixer. The gas/liquid metal mixture is heated by the collected solar energy and moves through the MHD generator thereby generating electrical power. The mixture is then separated and recycled.

Lee, J. H.; Hohl, F.

1983-06-01

214

Satellite power systems for large-scale power generation  

Microsoft Academic Search

The economic feasibility of satellite power systems (SPS) for large scale industrial applications is investigated. Systems for converting sunlight into electricity can be based on quantum devices or thermal cycles. Approaches utilizing laser radiation or microwaves have been proposed for transmitting the energy from the satellite to a ground receiving station. The employment of microwaves appears currently to be best

C. R. Woodcock

1976-01-01

215

Power processing issues for micro-power electrostatic generators  

Microsoft Academic Search

For various monitoring and sensing applications it is desirable to power the electronics by scavenging energy from any locally available source. A prototype generator for low frequency (human body) motion has been developed using a micro-machined (MEMS) implementation of an inertial generator based on a moving-plate capacitor. The prototype generates pulses of 300 V on a 10 pF capacitor. This

B. H. Stark; P. D. Mitcheson; P. Miao; T. C. Green; E. M. Yeatman; A. S. Holmes

2004-01-01

216

New Generation Power System for Space Applications  

NASA Technical Reports Server (NTRS)

The Deep Space Avionics (DSA) Project is developing a new generation of power system building blocks. Using application specific integrated circuits (ASICs) and power switching modules a scalable power system can be constructed for use on multiple deep space missions including future missions to Mars, comets, Jupiter and its moons. The key developments of the DSA power system effort are five power ASICs and a mod ule for power switching. These components enable a modular and scalab le design approach, which can result in a wide variety of power syste m architectures to meet diverse mission requirements and environments . Each component is radiation hardened to one megarad) total dose. The power switching module can be used for power distribution to regular spacecraft loads, to propulsion valves and actuation of pyrotechnic devices. The number of switching elements per load, pyrotechnic firin gs and valve drivers can be scaled depending on mission needs. Teleme try data is available from the switch module via an I2C data bus. The DSA power system components enable power management and distribution for a variety of power buses and power system architectures employing different types of energy storage and power sources. This paper will describe each power ASIC#s key performance characteristics as well a s recent prototype test results. The power switching module test results will be discussed and will demonstrate its versatility as a multip urpose switch. Finally, the combination of these components will illu strate some of the possible power system architectures achievable fro m small single string systems to large fully redundant systems.

Jones, Loren; Carr, Greg; Deligiannis, Frank; Lam, Barbara; Nelson, Ron; Pantaleon, Jose; Ruiz, Ian; Treicler, John; Wester, Gene; Sauers, Jim; Giampoli, Paul; Haskell, Russ; Mulvey, Jim; Repp, John

2004-01-01

217

Selection and Evaluation of Thermal Interface Materials for Reduction of the Thermal Contact Resistance of Thermoelectric Generators  

NASA Astrophysics Data System (ADS)

A variety of thermal interface materials (TIMs) were investigated to find a suitable TIM for improving the performance of thermoelectric power generators (TEGs) operating in the medium-temperature range (600-900 K). The thermal resistance at the thermal interface between which the TIM was inserted was evaluated. The TIMs were chosen on the basis of their thermal stability when used with TEGs operating at medium temperatures, their electrical insulating properties, their thermal conductivity, and their thickness. The results suggest that the boron nitride (BN)-based ceramic coating, Whity Paint, and the polyurethane-based sheet, TSU700-H, are suitable TIMs for the heat source and heat sink sides, respectively, of the TEG. Use of these effectively enhances TEG performance because they reduce the thermal contact resistance at the thermal interface.

Sakamoto, Tatsuya; Iida, Tsutomu; Sekiguchi, Takeshi; Taguchi, Yutaka; Hirayama, Naomi; Nishio, Keishi; Takanashi, Yoshifumi

2014-05-01

218

Thermal buffering of receivers for parabolic dish solar thermal power plants  

NASA Technical Reports Server (NTRS)

A parabolic dish solar thermal power plant comprises a field of parabolic dish power modules where each module is composed of a two-axis tracking parabolic dish concentrator which reflects sunlight (insolation) into the aperture of a cavity receiver at the focal point of the dish. The heat generated by the solar flux entering the receiver is removed by a heat transfer fluid. In the dish power module, this heat is used to drive a small heat engine/generator assembly which is directly connected to the cavity receiver at the focal point. A computer analysis is performed to assess the thermal buffering characteristics of receivers containing sensible and latent heat thermal energy storage. Parametric variations of the thermal inertia of the integrated receiver-buffer storage systems coupled with different fluid flow rate control strategies are carried out to delineate the effect of buffer storage, the transient response of the receiver-storage systems and corresponding fluid outlet temperature. It is concluded that addition of phase change buffer storage will substantially improve system operational characteristics during periods of rapidly fluctuating insolation due to cloud passage.

Manvi, R.; Fujita, T.; Gajanana, B. C.; Marcus, C. J.

1980-01-01

219

Factors Utilized in Thermal Power Plant Siting: A Review Through the Mid-1970's.  

National Technical Information Service (NTIS)

The report describes the evolution of siting factors and criteria for locating thermal electric power generating stations. Until the early 1960s, such factors were generally limited to land costs, site preparation costs, delivered fuel costs, transmission...

B. C. Dysart A. Kellizy

1978-01-01

220

Chemical energy storage system for SEGS solar thermal power plant  

NASA Astrophysics Data System (ADS)

In October 1988, a symposium was held in Helendale, California, to discuss thermal energy storage (TES) concepts applicable to medium temperature (200 to 400 C) solar thermal electric power plants, in general, and the solar electric generating system (SEGS) plants developed by Luz International, in particular. Chemical reaction energy storage based on the reversible reaction between metal oxides and metal hydroxides was identified as a leading candidate for meeting Luz International's cost and performance requirements. The principal objectives of this study were to identify the design conditions, requirements, and potential feasibility for a chemical energy storage system applied to a SEGS solar thermal power plant. The remaining sections of this report begin by providing an overview of the chemical reaction energy storage concept and a SEGS solar thermal power plant. Subsequent sections describe the initial screening of alternative evaporation energy sources and the more detailed evaluation of design alternatives considered for the preferred evaporation energy source. The final sections summarize the results, conclusions, and recommendations.

Brown, D. R.; Lamarche, J. L.; Spanner, G. E.

1991-09-01

221

Thermal reliability of power insulated gate bipolar transistor (IGBT) modules  

Microsoft Academic Search

Thermal behavior of power insulated gate bipolar transistor (IGBT) modules was studied in this paper experimentally. Due primarily to the thermal mismatch in IGBT sandwich structure, thermal stress induced solder fatigue failures, such as the forming and growing of voids and cracks in IGBT solder layers, were quasi-dynamically observed in thermal cycling test. Thermal stress simulation provided stress distribution and

Wuchen Wu; Guo Gao; Limin Dong; Zhengyuan Wang; Marcel Held; Peter Jacob; Paolo Scacco

1996-01-01

222

Flywheel-powered X-ray generator  

NASA Technical Reports Server (NTRS)

The use of a small flywheel appears to be a practical alternative to other power sources for mobile X-ray system applications. A 5 kg flywheel has been constructed which runs at 10 krpm and stores 30 KJ while requiring less than 500 W to bring the system up to speed. The wheel is coupled to an aircraft alternator and can yield pulsed power levels over 50 KWp. The aircraft alternator has the advantage of high frequency output which has also permitted the design of smaller high voltage transformers. A series of optical sensors detecting shaft position function as an electronic commutator so that the alternator may operate as a motor to bring the wheel up to operating speed. The system permits the generation of extremely powerful X-rays from a variety of low power sources such as household power outlets, automobile batteries or sources of poorly regulated electrical power such as those found in third world countries.

Siedband, M. P.

1984-01-01

223

43 CFR 431.6 - Power generation estimates.  

Code of Federal Regulations, 2010 CFR

...2009-10-01 2009-10-01 false Power generation estimates. 431.6 Section...INTERIOR GENERAL REGULATIONS FOR POWER GENERATION, OPERATION, MAINTENANCE...ARIZONA/NEVADA § 431.6 Power generation estimates....

2009-10-01

224

43 CFR 431.6 - Power generation estimates.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Power generation estimates. 431.6 Section...INTERIOR GENERAL REGULATIONS FOR POWER GENERATION, OPERATION, MAINTENANCE...ARIZONA/NEVADA § 431.6 Power generation estimates....

2010-10-01

225

43 CFR 431.4 - Power generation responsibilities.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Power generation responsibilities. 431.4...INTERIOR GENERAL REGULATIONS FOR POWER GENERATION, OPERATION, MAINTENANCE...ARIZONA/NEVADA § 431.4 Power generation responsibilities. (a)...

2010-10-01

226

43 CFR 431.4 - Power generation responsibilities.  

Code of Federal Regulations, 2010 CFR

...2009-10-01 2009-10-01 false Power generation responsibilities. 431.4...INTERIOR GENERAL REGULATIONS FOR POWER GENERATION, OPERATION, MAINTENANCE...ARIZONA/NEVADA § 431.4 Power generation responsibilities. (a)...

2009-10-01

227

Use of a Best Estimate Power Monitoring Tool to Maximize Power Plant Generation  

SciTech Connect

The Best Estimate Power Monitor (BEPM) is a tool that was developed to maximize nuclear power plant generation, while ensuring regulatory compliance in the face of venturi fouling, industry ultra-sonic flowmeter issues and other technical challenges. The BEPM uses ASME approved 'best estimate' methodology described in PTC 19.1-1985, 'Measurement Uncertainty', Section 3.8, 'Weighting Method'. The BEPM method utilizes many different and independent indicators of core thermal power and independently computes the core thermal power (CTP) from each parameter. The uncertainty of each measurement is used to weight the results of the best estimate computation of CTP such that those with lower uncertainties are weighted more heavily in the computed result. The independence of these measurements is used to minimize the uncertainty of the aggregate result, and the overall uncertainty can be much lower than the uncertainties of any of the individual measured parameters. Examples of the Balance of Plant parameters used in the BEPM are turbine first stage pressure, venturi feedwater flow, condensate flow, main steam flow, high pressure turbine exhaust pressure, low pressure turbine inlet pressure, the two highest pressure feedwater heater extraction pressures, and final feedwater temperature. The BEPM typically makes use of installed plant instrumentation that provide data to the plant computer. Therefore, little or no plant modification is required. In order to compute core thermal power from the independent indicators, a set of baseline data is used for comparison. These baseline conditions are taken from a day when confidence in the value of core thermal power is high (i.e., immediately post outage when venturi fouling is not an issue or from a formal tracer test). This provides the reference point on which to base the core thermal power calculations for each of the independent parameters. The BEPM is effective only at the upper end of the power range, where the independent parameters generally vary in a highly predictable way with changes in core thermal power. This paper will present a detailed description of the BEPM methodology, examples of the BEPM output, and examples of field application. Industry applications of the BEPM include monitoring venturi fouling, verification of an ultrasonic flow meter when used as in input to the secondary calorimetric, and monitoring the performance of other plant equipment that can affect core thermal power. When used routinely as part of a thermal performance monitoring program, the BEPM can be extremely effective in generation maximization, identification of equipment degradation or failure, and identification of potential overpower conditions. (author)

Dziuba, Lindsey L. [ILD, Inc., 8867 Highland Road n.378, Baton Rouge, Louisiana, 70808 (United States)

2006-07-01

228

Loss calculation and thermal analysis of a high-speed generator  

Microsoft Academic Search

The machine under study is a permanent magnet synchronous generator intended for operation at high speeds together with a micro-turbine in a combined heat and power (CHP) unit. Target power is 110 kW at 70000 rpm. The study is both theoretical and experimental since it includes calculation of loss distribution and thermal analysis together with calorimetric measurements of losses and

O. Aglen

2003-01-01

229

ZERO EMISSION POWER GENERATION TECHNOLOGY DEVELOPMENT  

Microsoft Academic Search

Clean Energy Systems (CES) was previously funded by DOE's ''Vision 21'' program. This program provided a proof-of-concept demonstration that CES' novel gas generator (combustor) enabled production of electrical power from fossil fuels without pollution. CES has used current DOE funding for additional design study exercises which established the utility of the CES-cycle for retrofitting existing power plants for zero-emission operations

Ronald Bischoff; Stephen Doyle

2005-01-01

230

Next generation micro-power systems  

Microsoft Academic Search

Emerging microsystems such as portable and implantable medical electronics, wireless microsensors and next-generation portable multimedia devices demand a dramatic reduction in energy consumption. The ultimate goal is to power these devices using energy harvesting techniques such as vibration-to-electric conversion or through wireless power transmission. A major opportunity to reduce the energy consumption of digital circuits is to scale supply voltages

Anantha P. Chandrakasan; Denis C. Daly; Joyce Kwong; Yogesh K. Ramadass

2008-01-01

231

Solar thermal electric power information user study  

SciTech Connect

The results of a series of telephone interviews with groups of users of information on solar thermal electric power are described. These results, part of a larger study on many different solar technologies, identify types of information each group needed and the best ways to get information to each group. The report is 1 of 10 discussing study results. The overall study provides baseline data about information needs in the solar community. An earlier study identified the information user groups in the solar community and the priority (to accelerate solar energy commercialization) of getting information to each group. In the current study only high-priority groups were examined. Results from five solar thermal electric power groups of respondents are analyzed: DOE-Funded Researchers, Non-DOE-Funded Researchers, Representatives of Utilities, Electric Power Engineers, and Educators. The data will be used as input to the determination of information products and services the Solar Energy Research Institute, the Solar Energy Information Data Bank Network, and the entire information outreach community should be preparing and disseminating.

Belew, W.W.; Wood, B.L.; Marle, T.L.; Reinhardt, C.L.

1981-02-01

232

Phase change material thermal power generator  

NASA Technical Reports Server (NTRS)

An energy producing device, for example a submersible vehicle for descending or ascending to different depths within water or ocean, is disclosed. The vehicle comprises a temperature-responsive material to which a hydraulic fluid is associated. A pressurized storage compartment stores the fluid as soon as the temperature-responsive material changes density. The storage compartment is connected with a hydraulic motor, and a valve allows fluid passage from the storage compartment to the hydraulic motor. An energy storage component, e.g. a battery, is connected with the hydraulic motor and is charged by the hydraulic motor when the hydraulic fluid passes through the hydraulic motor. Upon passage in the hydraulic motor, the fluid is stored in a further storage compartment and is then sent back to the area of the temperature-responsive material.

Jones, Jack A. (Inventor); Chao, Yi (Inventor); Valdez, Thomas I. (Inventor)

2011-01-01

233

MHD-steam thermal power plant electrical stations with zero stack emission  

SciTech Connect

A system study of a combined cycle MHD-steam thermal power plant electrical station with zero stack emission through recirculation of CO{sub 2}, is presented. The design of the MHD generator of the topper is done by means of a quasi-one dimensional optimization model. The technology of the components is conventional. An overall efficiency larger than 40% for power plants with thermal power inputs above 1,000 MWth, is obtained.

Borghi, C.A.; Ribani, P.L. [Univ. of Bologna (Italy). Inst. of Electrotechnics] [Univ. of Bologna (Italy). Inst. of Electrotechnics

1996-03-01

234

Life assessment of large power cables in fossil fuel generating stations  

Microsoft Academic Search

As part of fossil generating station upgrades, the major components of the electrical station service system (i.e., the large power cables for the generator leads, transformer secondaries, and motor feeders) are evaluated for increased capacity, continued reliability, and additional service life. This paper discusses the cable aging mechanisms for fossil-power stations, including thermal aging of insulation, insulation voltage stress, corrosion

Petty

1989-01-01

235

A numerical investigation of a thermodielectric power generation system  

NASA Astrophysics Data System (ADS)

The performance of a novel micro-thermodielectric power generation system was investigated in order to determine if thermodielectric power generation can be practically employed and if its performance can compete with current portable power generation technologies. Thermodielectric power generation is a direct energy conversion technology that converts heat directly into high voltage direct current. It requires dielectric (i.e., capacitive) materials whose charge storing capabilities are a function of temperature. This property can be exploited by heating these materials after they are charged; as their temperature increases, their charge storage capability decreases, forcing them to eject a portion of their surface charge. This ejected charge can then be supplied to an appropriate electronic storage device. There are several advantages associated with thermodielectric energy conversion; first, it requires heat addition at relatively low conventional power generation temperatures, i.e., less than 600 °K, and second, devices that utilize it have the potential for excellent power density and device reliability. The predominant disadvantage of using this power generation technique is that the device must operate in an unsteady manner; this can lead to substantial heat transfer losses that limit the device's thermal efficiency. The studied power generation system was designed so that the power generating components of the system (i.e., the thermodielectric materials) are integrated within a micro-scale heat exchange apparatus designed specifically to provide the thermodielectric materials with the unsteady heating and cooling necessary for efficient power generation. This apparatus is designed to utilize a liquid as a working fluid in order to maximize its heat transfer capabilities, minimize the size of the heat exchanger, and maximize the power density of the power generation system. The thermodielectric materials are operated through a power generation cycle that consists of four processes; the first process is a charging process, during which an electric field is applied to a thermodielectric material, causing it to acquire electrical charge on its surface (this process is analogous to the isentropic compression process of a Brayton cycle). The second process is a heating process in which the temperature of the dielectric material is increased via heat transfer from an external source. During this process, the thermodielectric material is forced to eject a portion of its surface charge because its charge storing capability decreases as the temperature increases; the ejected charge is intended for capture by external circuitry connected to the thermodielectric material, where it can be routed to an electrochemical storage device or an electromechanical device requiring high voltage direct current. The third process is a discharging process, during which the applied electric field is reduced to its initial strength (analogous to the isentropic expansion process of a Brayton cycle). The final process is a cooling process in which the temperature of the dielectric material is decreased via heat transfer from an external source, returning it to its initial temperature. Previously, predicting the performance of a thermodielectric power generator was hindered by a poor understanding of the material's thermodynamic properties and the effect unsteady heat transfer losses have on system performance. In order to improve predictive capabilities in this study, a thermodielectric equation of state was developed that relates the strength of the applied electric field, the amount of surface charge stored by the thermodielectric material, and its temperature. This state equation was then used to derive expressions for the material's thermodynamic states (internal energy, entropy), which were subsequently used to determine the optimum material properties for power generation. Next, a numerical simulation code was developed to determine the heat transfer capabilities of a micro-scale parallel plate heat recuperator (MPPHR), a device desig

Sklar, Akiva A.

236

Thermoelectric unicouple used for power generation  

NASA Technical Reports Server (NTRS)

A high-efficiency thermoelectric unicouple is used for power generation. The unicouple is formed with a plurality of legs, each leg formed of a plurality of segments. The legs are formed in a way that equalizes certain aspects of the different segments. Different materials are also described.

Caillat, Thierry (Inventor); Zoltan, Andrew (Inventor); Zoltan, Leslie (Inventor); Snyder, Jeffrey (Inventor)

2004-01-01

237

Plasma plume MHD power generator and method  

DOEpatents

A method is described of generating power at a situs exposed to the solar wind which comprises creating at separate sources at the situs discrete plasma plumes extending in opposed directions, providing electrical communication between the plumes at their source and interposing a desired electrical load in the said electrical communication between the plumes.

Hammer, J.H.

1993-08-10

238

Permanent Magnet Generators for Portable Military Power.  

National Technical Information Service (NTIS)

The United States Army MERDC has a continuing program to develop and update a family of portable and/or mobile power generation sets for use by the United States military services. In the past decade, a number of new permanent magnet materials have been d...

E. F. Hammond A. E. King A. L. Jokl

1971-01-01

239

Environmental effects of tidal power generating schemes  

Microsoft Academic Search

The Severn Estuary has been proposed as a site for a tidal power generating barrage. The character of the existing environment would be changed but, if the risks of accumulating pollutants and eutrophication can be avoided, the reduction in turbidity and tidal scour could increase species diversity and productivity. The interests of wading birds and wildfowl could be accommodated by

C. Mettam

1978-01-01

240

Application of induction generators in power systems  

NASA Astrophysics Data System (ADS)

The application of induction generators in power systems is discussed. The performance of induction generators as function of machine and system parameters and as function of var source control is evaluated and compared with that of synchronous generators. Results are presented so as to allow identification of system conditions favoring the application of induction generators and to estimate var source requirements. Fundamentals of induction generator transient behavior and determinations of the effect of modeling detail are discussed. The importance of rotor flux transient effects in high efficiency (low slip) designs is determined. Although the thrust of the investigations was to explore application of large scale induction machines (500 to 1000 MVA) the range of parameters studied and their presentation in normalized form allows the reslts to be applicable to all sizes of machines.

Demello, F. P.; Hannett, L. N.; Feltes, J. W.

1981-10-01

241

Recent advances in RF power generation  

SciTech Connect

This paper is a review of the progress and methods used in RF generation for particle accelerators. The frequencies of interest are from a few megahertz to 100 GHz, and the powers are for super linear collider applications, but in this case the pulses are short, generally below 1 {mu}s. The very high-power, short-pulse generators are only lightly reviewed here, and for more details the reader should follow the specialized references. Different RF generators excel over various parts of the frequency spectrum. Below 100 MHz solid-state devices and gridded tubes prevail, while the region between 400 MHz and 3 GHz, the cyclotron-resonant devices predominate, and above 250 GHz, Free-Electron Lasers and ubitrons are the most powerful generators. The emphasis for this review is on microwave generation at frequencies below 20 GHz, so the cyclotron-resonant devices are only partially reviewed, while the progress on free-electron laser and ubitrons is not reviewed in this paper. 39 refs., 4 figs.

Tallerico, P.J.

1990-01-01

242

Apollo experience report: Power generation system  

NASA Technical Reports Server (NTRS)

A comprehensive review of the design philosophy and experience of the Apollo electrical power generation system is presented. The review of the system covers a period of 8 years, from conception through the Apollo 12 lunar-landing mission. The program progressed from the definition phase to hardware design, system development and qualification, and, ultimately, to the flight phase. Several problems were encountered; however, a technology evolved that enabled resolution of the problems and resulted in a fully manrated power generation system. These problems are defined and examined, and the corrective action taken is discussed. Several recommendations are made to preclude similar occurrences and to provide a more reliable fuel-cell power system.

Bell, D., III; Plauche, F. M.

1973-01-01

243

Optical generation of radio-frequency power  

SciTech Connect

An optical technique for high-power radio-frequency (RF) signal generation is described. The technique uses a unique photodetector based on a traveling-wave design driven by an appropriately modulated light source. The traveling-wave photodetector (TWPD) exhibits simultaneously a theoretical quantum efficiency approaching 100 % and a very large electrical bandwidth. Additionally, it is capable of dissipating the high-power levels required for the RF generation technique. The modulated light source is formed by either the beating together of two lasers or by the direct modulation of a light source. A system example is given which predicts RF power levels of 100`s of mW`s at millimeter wave frequencies with a theoretical ``wall-plug`` efficiency approaching 34%.

Hietala, V.M.; Vawter, G.A.; Brennan, T.M.; Hammons, B.E.; Meyer, W.J.

1994-11-01

244

Thermoelectric power generation system optimization studies  

NASA Astrophysics Data System (ADS)

A significant amount of energy we consume each year is rejected as waste heat to the ambient. Conservative estimates place the quantity of energy wasted at about 70%. Converting the waste heat into electrical power would be convenient and effective for a number of primary and secondary applications. A viable solution for converting waste heat into electrical energy is to use thermoelectric power conversion. Thermoelectric power generation is based on solid state technology with no moving parts and works on the principle of Seebeck effect. In this work a thermoelectric generator (TEG) system simulator was developed to perform various parametric and system optimization studies. Optimization studies were performed to determine the effect of system size, exhaust and coolant ow conditions, and thermoelectric material on the net gains produced by the TEG system and on the optimum TEG system design. A sports utility vehicle was used as a case study for the application of TEG in mobile systems.

Karri, Madhav A.

245

Efficient, monochromatic, high-power microwave generator  

SciTech Connect

Microwave generation by electron beams in virtual cathode configurations can achieve significant power levels. However, most designs inherently have two competing mechanisms generating microwaves; namely the oscillating virtual cathode and the reflexing electrons. These two mechanisms tend to interfere destructively with each other. Specifically, the reflexing electrons subject the electron beam to two-stream instability, causing considerable heating of the electron beam. In addition, the space-charge of the reflexing electrons can cause the diode independence to fluctuate, resulting in oscillations of the electron beam energy. We have investigated a novel idea to remove these undesirable effects and we found that high-power, narrow-band, and monochromatic microwaves could be generated with efficiency of 10 to 20%. 16 refs., 7 figs.

Kwan, T.J.T.; Snell, C.M.

1986-01-01

246

Advanced Soldier Thermoelectric Power System for Power Generation from Battlefield Heat Sources  

SciTech Connect

The U.S. military uses large amounts of fuel during deployments and battlefield operations. This project sought to develop a lightweight, small form-factor, soldier-portable advanced thermoelectric (TE) system prototype to recover and convert waste heat from various deployed military equipment (i.e., diesel generators/engines, incinerators, vehicles, and potentially mobile kitchens), with the ultimate purpose of producing power for soldier battery charging, advanced capacitor charging, and other battlefield power applications. The technical approach employed microchannel technology, a unique “power panel” approach to heat exchange/TE system integration, and newly-characterized LAST (lead-antimony-silver-telluride) and LASTT (lead-antimony-silver-tin-telluride) TE materials segmented with bismuth telluride TE materials in designing a segmented-element TE power module and system. This project researched never-before-addressed system integration challenges (thermal expansion, thermal diffusion, electrical interconnection, thermal and electrical interfaces) of designing thin “power panels” consisting of alternating layers of thin, microchannel heat exchangers (hot and cold) sandwiching thin, segmented-element TE power generators. The TE properties, structurally properties, and thermal fatigue behavior of LAST and LASTT materials were developed and characterized such that the first segmented-element TE modules using LAST / LASTT materials were fabricated and tested at hot-side temperatures = 400 °C and cold-side temperatures = 40 °C. LAST / LASTT materials were successfully segmented with bismuth telluride and electrically interconnected with diffusion barrier materials and copper strapping within the module electrical circuit. A TE system design was developed to produce 1.5-1.6 kW of electrical energy using these new TE modules from the exhaust waste heat of 60-kW Tactical Quiet Generators as demonstration vehicles.

Hendricks, Terry J.; Hogan, Tim; Case, Eldon D.; Cauchy, Charles J.

2010-09-01

247

Spin-on-doping for output power improvement of silicon nanowire array based thermoelectric power generators  

NASA Astrophysics Data System (ADS)

The output power of a silicon nanowire array (NWA)-bulk thermoelectric power generator (TEG) with Cu contacts is improved by spin-on-doping (SOD). The Si NWAs used in this work are fabricated via metal assisted chemical etching (MACE) of 0.01-0.02 ? cm resistivity n- and p-type bulk, converting ˜4% of the bulk thickness into NWs. The MACE process is adapted to ensure crystalline NWs. Current-voltage and Seebeck voltage-temperature measurements show that while SOD mainly influences the contact resistance in bulk, it influences both contact resistance and power factor in NWA-bulk based TEGs. According to our experiments, using Si NWAs in combination with SOD increases the output power by an order of 3 under the same heating power due to an increased power factor, decreased thermal conductivity of the NWA and reduced Si-Cu contact resistance.

Xu, B.; Fobelets, K.

2014-06-01

248

Chemical energy storage system for SEGS solar thermal power plant  

NASA Astrophysics Data System (ADS)

The Pacific Northwest Laboratory evaluated the potential feasibility of using chemical energy storage at the Solar Electric Generating System (SEGS) power plants developed by Luz International. Like sensible or latent heat energy storage systems, chemical energy storage can be beneficially applied to solar thermal power plants to dampen the impact of cloud transients, extend the daily operating period, and/or allow a higher fraction of power production to occur during high-valued peak demand periods. Higher energy storage densities make chemical energy storage a potentially attractive option. The results of the evaluation indicated that a system based on the reversible reaction, CaO + H2O = Ca(OH)2, could be technically and economically feasible for this application, but many technical and economic issues must be resolved.

Brown, D. R.; Lamarche, J. L.; Spanner, G. E.

1992-04-01

249

Thermoelectric Power Generator Design for Maximum Power: It's All About ZT  

NASA Astrophysics Data System (ADS)

There is a significant amount of literature that discusses thermoelectric power generator (TEG) design, but much of it overly simplifies the design space and therefore the results have limited use in designing real-life systems. This paper develops a more comprehensive model of the thermal and electrical interactions of a TEG in a system with known hot-side and cold-side thermal resistances and corresponding constant system temperature differential. Two design scenarios are investigated for common TEG system applications. In one method, the power from a TEG is maximized for a given electrical load, simulating a case where the TEG is electrically in series with a known load such as a fan. In the second design scenario, the power from a TEG is maximized for a given electrical load resistance ratio, n (the ratio between the external load resistance and the internal TEG resistance), simulating an application where the TEG is electrically in series with a load-matching converter. An interesting conclusion from this work is that, in the first design scenario, the electrical load resistance ratio, n, that maximizes TEG power occurs at ?{1 + ZT} (where ZT is the thermoelectric figure of merit) instead of 1 as reported previously in literature. Equally interesting is that, if you define an analogous thermal resistance ratio, m' (representing the ratio between the TEG thermal resistance at open-circuit conditions and the system thermal resistance), the maximum power in both design scenarios occurs at ?{1 + ZT} instead of the commonly cited value of 1. Furthermore, results are presented for real-life designs that incorporate electrical and thermal losses common to realistic TEG systems such as electrical contact resistance and thermal bypass around the TEG due to sealing.

McCarty, R.

2013-07-01

250

ENHANCED THERMAL VACUUM TEST CAPABILITY FOR RADIOISOTOPE POWER SYSTEMS AT THE IDAHO NATIONAL LABORATORY BETTER SIMULATES ENVIRONMENTAL CONDITIONS OF SPACE  

SciTech Connect

The Idaho National Laboratory (INL) is preparing to fuel and test the Advanced Stirling Radioisotope Generator (ASRG), the next generation space power generator. The INL identified the thermal vacuum test chamber used to test past generators as inadequate. A second vacuum chamber was upgraded with a thermal shroud to process the unique needs and to test the full power capability of the new generator. The thermal vacuum test chamber is the first of its kind capable of testing a fueled power system to temperature that accurately simulate space. This paper outlines the new test and set up capabilities at the INL.

J. C. Giglio; A. A. Jackson

2012-03-01

251

DOWNHOLE POWER GENERATION AND WIRELESS COMMUNICATIONS  

SciTech Connect

The second quarter of the project was dedicated to convert the conceptual designs for the wireless tool and power generator into mechanical and electrical drawings as well as software code to create the new system. The tasks accomplished during this report period were: (1) Basic mechanical design for the wireless communications system was created and the detailed drawings were started. (2) Basic design for the power generator system was created and the detailed machining drawings were started. The generator design was modified to provide a direct action between the wellbore fluid flow and the piezoelectric stack to generate energy. The new design eliminates the inefficiencies related to picking up outside the tubing wall the pressure fluctuations occurring inside the tubing walls. (3) The new piezoelectric acoustic generator design was created and ordered from the manufacturer. The system will be composed of 40 ceramic wafers electrically connected in parallel and compressed into a single generator assembly. (4) The acoustic two-way communications requirements were also defined and the software and hardware development were started. (5) The electrical hardware development required to transmit information to the surface and to receive commands from the surface was started.

Paul Tubel

2003-04-24

252

78 FR 32385 - Exelon Generation Company, LLC; CER Generation II, LLC; Constellation Mystic Power, LLC...  

Federal Register 2010, 2011, 2012, 2013

...Constellation NewEnergy, Inc.; Constellation Power Source Generation, Inc.; Criterion Power Partners, LLC; Notice of Petition for...Constellation NewEnergy, Inc., Constellation Power Source Generation, Inc. and Criterion Power...

2013-05-30

253

Isotope powered stirling generator for terrestrial applications  

NASA Astrophysics Data System (ADS)

An electric power supply, small enough to be man-portable, is being developed for remote, terrestrial applications. This system is designed for an operating lifetime of five years without maintenance or refueling. A small Radioisotope Stirling Generator (RSG) has been developed. The energy source of the generator is a 60 watt plutonium-238 fuel clad used in the General Purpose Heat Sources (GPHS) developed for space applications. A free piston Stirling ENgine drives a linear alternator to convert the heat to power. The system weighs about 7.5 kg and produces 11 watts AC power with a conversion efficiency of 18.5%. Two engine models have been designed, fabricated, and tested to data: (a) a development model instrumented to confirm and test parameters, and (b) an electrically heated model with an electrical heater equipped power input leads. Critical components have been tested for 10,000 to 20,000 hours. One complete generator has been operating for over 11,000 hours. Radioisotope heated prototypes are expected to be fabricated and tested in late 1995.

Tingey, Garth L.; Sorensen, Gerald C.; Ross, Brad A.

1995-01-01

254

Nuclear power generating station equipment qualification apparatus  

SciTech Connect

This patent describes a nuclear power plant having an object piece of qualified equipment, an apparatus for monitoring the object piece of qualified equipment. It comprises: passive means for detecting a gamma ray does of radiation received by the object piece; means for determining a thermal history of the object piece; means for detecting neutron-induced fission; monitor blocks, the gamma ray detection means, the thermal history determining means and the fission detection means enclosed in one of the monitor blocks, each of the monitor blocks having first sealing means for individually sealing the each monitor block; and means for housing the monitor blocks in close proximity to the object piece, the housing means having a body portion and a cover portion, a cavity being formed in the body portion and the monitor blocks being disposed in the cavity.

Fero, A.H.

1991-04-30

255

Coal Gasification for Power Generation, 3. edition  

SciTech Connect

The report provides a concise look at the challenges faced by coal-fired generation, the ability of coal gasification to address these challenges, and the current state of IGCC power generation. Topics covered include: an overview of Coal Generation including its history, the current market environment, and the status of coal gasification; a description of gasification technology including processes and systems; an analysis of the key business factors that are driving increased interest in coal gasification; an analysis of the barriers that are hindering the implementation of coal gasification projects; a discussion of Integrated Gasification Combined Cycle (IGCC) technology; an evaluation of IGCC versus other generation technologies; a discussion of IGCC project development options; a discussion of the key government initiatives supporting IGCC development; profiles of the key gasification technology companies participating in the IGCC market; and, a detailed description of existing and planned coal IGCC projects.

NONE

2007-11-15

256

Qualitative and quantitative modeling of steam generator in a nuclear power plant using logic processor  

Microsoft Academic Search

In this work, we propose a qualitative and quantitative modeling method for a steam generator in a nuclear power plant. Modeling the steam generator is known to be difficult due to several facts especially, the dynamics of the steam generator is nonminimum phase which is mainly caused by the swell and shrink phenomena from thermal effects. In order to overcome

Myung-Geun Chun; Sam-Sun Ma; Myung-Soo Lee

1997-01-01

257

D0 Experimental Area Emergency Backup Power and Generator Test  

Microsoft Academic Search

The DO experimental area has a generator designated as emergency power. This generator provides power for critical loads and starts automatically upon loss of commercial power. This note concerns the testing of this generator. A list of loads is attached to this note. One of the loads on the emergency power grid is a 10KVA Uninterruptable Power Supply(UPS). The UPS

D. Markley

1991-01-01

258

Electrokinetic Power Generation from Liquid Water Microjets  

SciTech Connect

Although electrokinetic effects are not new, only recently have they been investigated for possible use in energy conversion devices. We have recently reported the electrokinetic generation of molecular hydrogen from rapidly flowing liquid water microjets [Duffin et al. JPCC 2007, 111, 12031]. Here, we describe the use of liquid water microjets for direct conversion of electrokinetic energy to electrical power. Previous studies of electrokinetic power production have reported low efficiencies ({approx}3%), limited by back conduction of ions at the surface and in the bulk liquid. Liquid microjets eliminate energy dissipation due to back conduction and, measuring only at the jet target, yield conversion efficiencies exceeding 10%.

Duffin, Andrew M.; Saykally, Richard J.

2008-02-15

259

Study of steam, helium and supercritical CO 2 turbine power generations in prototype fusion power reactor  

Microsoft Academic Search

Power generation systems such as steam turbine cycle, helium turbine cycle and supercritical CO2 (S-CO2) turbine cycle are examined for the prototype nuclear fusion reactor. Their achievable cycle thermal efficiencies are revealed to be 40%, 34% and 42% levels for the heat source outlet coolant temperature of 480°C, respectively, if no other restriction is imposed. In the current technology, however,

Shintaro Ishiyama; Yasushi Muto; Yasuyoshi Kato; Satoshi Nishio; Takumi Hayashi; Yasunobu Nomoto

2008-01-01

260

An advanced zero emission power cycle with integrated low temperature thermal energy  

Microsoft Academic Search

An innovative zero emission hybrid cycle named HICES (hybrid and improved CES cycle) is presented in this paper. It can utilize fossil fuel and low quality thermal energy such as waste heat from industrial processes and solar thermal energy for highly efficient electric power generation. In the HICES cycle, natural gas is internally combusted with pure oxygen. External low quality

Chenhua Gou; Ruixian Cai; Guoqiang Zhang

2006-01-01

261

Method of operating a thermal engine powered by a chemical reaction  

DOEpatents

The invention involves a novel method of increasing the efficiency of a thermal engine. Heat is generated by a non-linear chemical reaction of reactants, said heat being transferred to a thermal engine such as Rankine cycle power plant. The novel method includes externally perturbing one or more of the thermodynamic variables of said non-linear chemical reaction. 7 figs.

Ross, J.; Escher, C.

1988-06-07

262

Core self-powered radiation detector for determining thermal and epithermal flux  

Microsoft Academic Search

A self-powered neutron detector in which two electrically isolated emitter electrodes are provided. The emitters are formed of different materials having differing responses to thermal and epithermal neutron flux. The separate signals generated between the separate emitters and a common collector electrode are used to determine the respective thermal and epithermal neutron fluxes for a more accurate flux mapping of

C. L. Chen; N. P. Goldstein; W. H. Todt

1983-01-01

263

Repetitively pulsed high power stacked Blumlein generators  

NASA Astrophysics Data System (ADS)

The stacked Blumlein pulse generators developed at the University of Texas at Dallas consist of several triaxial Blumleins stacked in series at one end. The lines are charged in parallel and synchronously commuted with a single switching element at the other end. In this way, relatively low charging voltages are multiplied to give the desired discharge voltage across an arbitrary load. Described here is the progress in development and characterization of these novel pulse-power generators capable of discharging at high repetition rates. The introduction of a tapered transmission line concept to the stacked Blumlein design provided fine tuning of output waveforms.

Davanloo, F.; Borovina, D. L.; Collins, C. B.; Agee, F. J.; Kingsley, L. E.

1995-05-01

264

Metastable photoenhanced thermal generation in a-SeTe alloys  

NASA Astrophysics Data System (ADS)

The mechanism of isothermal bulk carrier generation in the dark and the sensitizing effects of prior penetrating illumination and thermal history have been investigated in a composition series of a-Se:Te alloy films using xerographic techniques. In all cases, thermal generation is characterized by the simultaneous production of free holes and deeply trapped negative space charge. Results suggest that dark carrier generation is controlled by deep native (thermodynamic) defect centers whose population at a given temperature below Tg can be temporarily altered by photo and/or thermal excitation.

Abkowitz, M.; Foley, G. M. T.; Markovics, J. M.; Palumbo, A. C.

1984-10-01

265

Complementary power output characteristics of electromagnetic generators and triboelectric generators  

NASA Astrophysics Data System (ADS)

Recently, a triboelectric generator (TEG) has been invented to convert mechanical energy into electricity by a conjunction of triboelectrification and electrostatic induction. Compared to the traditional electromagnetic generator (EMG) that produces a high output current but low voltage, the TEG has different output characteristics of low output current but high output voltage. In this paper, we present a comparative study regarding the fundamentals of TEGs and EMGs. The power output performances of the EMG and the TEG have a special complementary relationship, with the EMG being a voltage source and the TEG a current source. Utilizing a power transformed and managed (PTM) system, the current output of a TEG can reach as high as ?3 mA, which can be coupled with the output signal of an EMG to enhance the output power. We also demonstrate a design to integrate a TEG and an EMG into a single device for simultaneously harvesting mechanical energy. In addition, the integrated NGs can independently output a high voltage and a high current to meet special needs.

Fan, Feng-Ru; Tang, Wei; Yao, Yan; Luo, Jianjun; Zhang, Chi; Wang, Zhong Lin

2014-04-01

266

18 CFR 801.12 - Electric power generation.  

... false Electric power generation. 801.12 Section 801.12 Conservation of Power and Water Resources SUSQUEHANNA RIVER BASIN COMMISSION GENERAL POLICIES § 801.12 Electric power generation. (a) Significant uses are...

2014-04-01

267

Wave and tide powered generation apparatus  

SciTech Connect

A wave and tide powered generation apparatus includes a frame which is fixed relative to the varying level of the body of water, and includes a float operably associated with the frame for movement in response to the varying level of the body of water. A rotatable drum is attached to the float and has a drive line with a middle portion wrapped around the rotatable drum. Upper and lower ends of the drive line are attached to upper and lower portions of the frame. Movement of the float upward or downward relative to the frame causes the rotatable drum to be rotated due to its engagement with the drive line. A power transfer apparatus transmits the rotary motion of the drum to a generator.

Suggs, L. F.

1985-09-03

268

ADVANCED CO2 CYCLE POWER GENERATION  

SciTech Connect

Research is being conducted under United States Department of Energy (DOE) Contract DE-FC26-02NT41621 to develop a conceptual design and determine the performance characteristics of a new IGCC plant configuration that facilitates CO{sub 2} removal for sequestration. This new configuration will be designed to achieve CO{sub 2} sequestration without the need for water gas shifting and CO{sub 2} separation, and may eliminate the need for a separate sequestration compressor. This research introduces a novel concept of using CO{sub 2} as a working fluid for an advanced coal gasification based power generation system, where it generates power with high system efficiency while concentrating CO{sub 2} for sequestration. This project supports the DOE research objective of development of concepts for the capture and storage of CO{sub 2}.

A. Nehrozoglu

2004-01-01

269

The New Generation of Thermal Mapping  

ERIC Educational Resources Information Center

Thermal imaging was used 60+ years ago to enable the targeting of heat-seeking missiles and seeing opposing forces at night. Today thermograpy is employed for myriad uses, from turning on faucets, to tracking and attacking enemies from aerial spy drones, to identifying the scope of moisture infiltration in building envelopes. Thermography for…

Patterson, Valerie B.

2012-01-01

270

Evaluation of solar thermal storage for base load electricity generation  

NASA Astrophysics Data System (ADS)

In order to stabilize solar electric power production during the day and prolong the daily operating cycle for several hours in the nighttime, solar thermal power plants have the options of using either or both solar thermal storage and fossil fuel hybridization. The share of solar energy in the annual electricity production capacity of hybrid solar-fossil power plants without energy storage is only about 20%. As it follows from the computer simulations performed for base load electricity demand, a solar annual capacity as high as 70% can be attained by use of a reasonably large thermal storage capacity of 22 full load operating hours. In this study, the overall power system performance is analyzed with emphasis on energy storage characteristics promoting a high level of sustainability for solar termal electricity production. The basic system parameters, including thermal storage capacity, solar collector size, and annual average daily discharge time, are presented and discussed.

Adinberg, R.

2012-10-01

271

Electric generating prospects for nuclear power  

Microsoft Academic Search

Most of the nuclear power plants in the U.S. today are of the light-water variety. In many parts of the U.S. these plants are competitive with plants burning coal, but the electricity that they generate will be more costly in the future as uranium supplies deplete. A promising possible answer to the cost problem is the fast-neutron reactor, which produces

Manson Benedict

1970-01-01

272

Opportunities for bioenergy in power generation  

Microsoft Academic Search

There is approximately 6 gigawatts (GW[sub e]) of biomass energy-based grid-connected generating capacity available in the United States. There are some utility owned plants, but most plants are primarily owned and operated by industrial entities. There is an additional 2.5 GW[sub e] capacity of municipal-solid-waste-powered facilities and a significant amount of remote, nongrid-connected, wood-fired capacity in the paper and wood

Mutanen

1993-01-01

273

A microturbine for electric power generation  

Microsoft Academic Search

A single-stage axial microturbine has been developed with a rotor diameter of 10mm. This turbine is a first step in the development of a microgenerator that produces electrical energy from fuel. The turbine is made of stainless steel using die-sinking electro-discharge machining. It has been tested to speeds up to 160,000rpm and generates a maximum mechanical power of 28W with

Jan Peirs; Dominiek Reynaerts; Filip Verplaetsen

2004-01-01

274

PIEZOELECTRIC MICRO POWER GENERATOR FOR ENERGY HARVESTING  

Microsoft Academic Search

A thin film lead zirconate titanate Pb(Zr,Ti)O3 (PZT), power generating device is developed. It is designed to resonate at specific vibrational frequencies from an ambient, vibrational energy source, thereby creating electrical energy via the piezoelectric effect. The energy harvesting device uses the piezoelectric d33 mode and is fabricated with three mask steps. Our cantilever device was designed to have a

R. Sood; Y. B. Jeon; S. G. Kim

275

Wood gasification for gas and power generation  

Microsoft Academic Search

A wood-chip gasifier supplying 4.05 million Btu (4.27 GJ)\\/hr of low-Btu fuel gas to a diesel-engine power generator has demonstrated its suitability as an efficient energy alternative for isolated communities in Canada's heavily wooded northern areas. Preliminary tests with wet spruce chips (58% water) yielded a clean 112-130 Btu\\/CF (4.4-5.07 MJ\\/m³) gas that is easily combusted in a naturally aspirated

A. Verma; G. A. Weisgerber

1980-01-01

276

Thermal analyses of power subsystem components  

NASA Technical Reports Server (NTRS)

The hiatus in the Space Shuttle (Orbiter) program provided time for an in-depth examination of all the subsystems and their past performance. Specifically, problems with reliability and/or operating limits were and continue to be of major engineering concern. The Orbiter Auxiliary Power Unit (APU) currently operates with electric resistance line heaters which are controlled with thermostats. A design option simplification of this heater subsystem is being considered which would use self-regulating heaters. A determination of the properties and thermal operating characteristics of these self-regulating heaters was needed. The Orbiter fuel cells are cooled with a freon loop. During a loss of external heat exchanger coolant flow, the single pump circulating the freon is to be left running. It was unknown what temperature and flow rate transient conditions of the freon would provide the required fuel cell cooling and for how long. The overall objective was the development of the thermal characterization and subsequent analysis of both the proposed self-regulating APU heater and the fuel cell coolant loop subsystem. The specific objective of the APU subsystem effort was to determine the feasibility of replacing the current heater and thermostat arrangement with a self-regulating heater. The specific objective of the fuel cell coolant subsystem work was to determine the tranient coolant temperature and associated flow rates during a loss-of-external heat exchanger flow.

Morehouse, Jeffrey H.

1990-01-01

277

Selection and development of small solar thermal power applications  

NASA Technical Reports Server (NTRS)

The paper discusses the approach of the JPL Point Focusing Thermal and Electric Power Applications Project to selecting and developing applications for point-focusing distributed-receiver solar thermal electric power systems. Six application categories are defined. Results of application studies of U.S. utilities are presented. The economic value of solar thermal power systems was found to range from $900 to $2100/kWe in small community utilities of the Southwest.

Bluhm, S. A.; Kuehn, T. J.; Gurfield, R. M.

1979-01-01

278

Cummins Power Generation SECA Phase 1  

SciTech Connect

The following report documents the progress of the Cummins Power Generation (CPG) SECA Phase 1 SOFC development and final testing under the U.S. Department of Energy Solid State Energy Conversion Alliance (SECA) contract DE-FC26-01NT41244. This report overviews and summarizes CPG and partner research development leading to successful demonstration of the SECA Phase 1 objectives and significant progress towards SOFC commercialization. Significant Phase 1 Milestones: (1) Demonstrated: (a) Operation meeting Phase 1 requirements on commercial natural gas. (b) LPG and Natural Gas CPOX fuel reformers. (c) SOFC systems on dry CPOX reformate. (c) Steam reformed Natural Gas operation. (d) Successful start-up and shut-down of SOFC system without inert gas purge. (e) Utility of stack simulators as a tool for developing balance of plant systems. (2) Developed: (a) Low cost balance of plant concepts and compatible systems designs. (b) Identified low cost, high volume components for balance of plant systems. (c) Demonstrated high efficiency SOFC output power conditioning. (d) Demonstrated SOFC control strategies and tuning methods. The Phase 1 performance test was carried out at the Cummins Power Generation facility in Minneapolis, Minnesota starting on October 2, 2006. Performance testing was successfully completed on January 4, 2007 including the necessary steady-state, transient, efficiency, and peak power operation tests.

Charles Vesely

2007-08-17

279

Numerical Simulation of the Thermally Generated Mountain-Foreland Circulation.  

National Technical Information Service (NTIS)

A hydrostatic mesoscale model is used for numerical simulation of the thermally generated mountain-foreland circulation. For an idealized large mountain valley especially the influence of different mountain shapes and various surface properties is investi...

F. Somieski

1987-01-01

280

Steam generator for thermal recovery system  

Microsoft Academic Search

A system for producing steam in a cogeneration plant for use in a thermal recovery process for crude oil using brackish water is described comprising: a central steam drum-separator unit; once-through shell and tube type heat exchangers, the heat exchangers surrounding the steam drum-separator unit, the brackish water circulating through the tubes of the heat exchangers; conduit means for coupling

1988-01-01

281

Experimental demonstration of thermal management using thermoelectric generation  

Microsoft Academic Search

It has been well established that thermal management of electronic equipment is a critical need for the continued success of the microelectronics industry. Portable electronic devices, such as notebook computers and cellular telephones, require that the thermal solution be small, light, and energy efficient. Small-scale thermoelectric (TE) modules can be used to generate electricity from the waste heat of the

Gary L. Solbrekken; Kazuaki Yazawa; Avram Bar-Cohen

2004-01-01

282

Design considerations for a coal gasification electric power generation plant  

SciTech Connect

The low environmental emissions and high efficiency of a coal gasification process make it highly attractive for electric power generation. Such a plant will be highly integrated and interactive. It will have many thermal, chemical, mechanical and electrical components with widely varying operating characteristics and constraints. The nature of the electricity production and use requires the gasification combined cycle plant to operate in a dynamic, load varying mode. This requires that careful consideration should be given to the design and selection of the system, the components and the control system. 5 refs.

Patel, A.S.; Hamid, T.

1981-01-01

283

Energy storage and thermal control system design status. [for space station power supplies  

NASA Technical Reports Server (NTRS)

The Space Station Freedom electric power system (EPS) will initially rely on photovoltaics for power generation and Ni/H2 batteries for electrical energy storage. The current design for the development status of two major subsystems in the PV Power Module is discussed. The energy storage subsystem comprised of high capacity Ni/H2 batteries and the single-phase thermal control system that rejects the excess heat generated by the batteries and other components associated with power generation andstorage is described.

Simons, Stephen N.; Willhoite, Bryan C.; Van Ommering, Gert

1989-01-01

284

Fresnel Concentrators for Space Solar Power and Solar Thermal Propulsion  

NASA Technical Reports Server (NTRS)

Large deployable Fresnel concentrators are applicable to solar thermal propulsion and multiple space solar power generation concepts. These concentrators can be used with thermophotovoltaic, solar thermionic, and solar dynamic conversion systems. Thin polyimide Fresnel lenses and reflectors can provide tailored flux distribution and concentration ratios matched to receiver requirements. Thin, preformed polyimide film structure components assembled into support structures for Fresnel concentrators provide the capability to produce large inflation-deployed concentrator assemblies. The polyimide film is resistant to the space environment and allows large lightweight assemblies to be fabricated that can be compactly stowed for launch. This work addressed design and fabrication of lightweight polyimide film Fresnel concentrators, alternate materials evaluation, and data management functions for space solar power concepts, architectures, and supporting technology development.

Bradford, Rodney; Parks, Robert W.; Craig, Harry B. (Technical Monitor)

2001-01-01

285

Thermal power systems small power systems application project: Siting issues for solar thermal power plants with small community applications  

NASA Technical Reports Server (NTRS)

The siting issues associated with small, dispersed solar thermal power plants for utility/small community applications of less than 10 MWe are reported. Some specific requirements are refered to the first engineering experiment for the Small Power Systems Applications (SPSA) Project. The background for the subsequent issue discussions is provided. The SPSA Project and the requirements for the first engineering experiment are described, and the objectives and scope for the report as a whole. A overview of solar thermal technologies and some technology options are discussed.

Holbeck, H. J.; Ireland, S. J.

1979-01-01

286

Turbostar: an ICF reactor using both direct and thermal power conversion. Revision 1  

SciTech Connect

Combining direct and thermal power conversion results in a 52% gross plant efficiency with DT fuel and 68% with advanced DD fuel. We maximize the fraction of fusion-yield energy converted to kinetic energy in a liquid-lithium blanket, and use this energy directly with turbine generators to produce electricity. We use the remainder of the energy to produce electricity in a standard Rankine thermal power conversion cycle.

Pitts, J.H.

1986-07-31

287

Output power analyses for the thermodynamic cycles of thermal power plants  

NASA Astrophysics Data System (ADS)

Thermal power plant is one of the important thermodynamic devices, which is very common in all kinds of power generation systems. In this paper, we use a new concept, entransy loss, as well as exergy destruction, to analyze the single reheating Rankine cycle unit and the single stage steam extraction regenerative Rankine cycle unit in power plants. This is the first time that the concept of entransy loss is applied to the analysis of the power plant Rankine cycles with reheating and steam extraction regeneration. In order to obtain the maximum output power, the operating conditions under variant vapor mass flow rates are optimized numerically, as well as the combustion temperatures and the off-design flow rates of the flue gas. The relationship between the output power and the exergy destruction rate and that between the output power and the entransy loss rate are discussed. It is found that both the minimum exergy destruction rate and the maximum entransy loss rate lead to the maximum output power when the combustion temperature and heat capacity flow rate of the flue gas are prescribed. Unlike the minimum exergy destruction rate, the maximum entransy loss rate is related to the maximum output power when the highest temperature and heat capacity flow rate of the flue gas are not prescribed.

Sun, Chen; Cheng, Xue-Tao; Liang, Xin-Gang

2014-05-01

288

Future Photovoltaic Power Generation for Space-Based Power Utilities  

NASA Astrophysics Data System (ADS)

A recent NASA program, Space Solar Power Exploratory Research and Technology (SERT), investigated the technologies needed to provide cost-competitive ground baseload electrical power from space based solar energy conversion. This goal mandated low cost, light weight gigawatt (GW) power generation. Investment in solar power generation technologies would also benefit high power military, commercial and science missions. These missions are generally those involving solar electric propulsion, surface power systems to sustain an outpost or a permanent colony on the surface of the moon or mars, space based lasers or radar, or as large earth orbiting power stations which can serve as central utilities for other orbiting spacecraft, or as in the SERT program, potentially beaming power to the earth itself. This paper will discuss requirements for the two latter options, the current state of the art of space solar cells, and a variety of both evolving thin film cells as well as new technologies which may impact the future choice of space solar cells for a high power mission application. The space world has primarily transitioned to commercially available III-V (GaInP/GaAs/Ge) cells with 24-26% air mass zero (AMO) efficiencies. Research in the III-V multi-junction solar cells has focused on fabricating either lattice-mismatched materials with optimum stacking bandgaps or new lattice matched materials with optimum bandgaps. In the near term this will yield a 30% commercially available space cell and in the far term possibly a 40% cell. Cost reduction would be achieved if these cells could be grown on a silicon rather than a germanium substrate since the substrate is ~65% of the cell cost or, better yet, on a polyimide or possibly a ceramic substrate. An overview of multi-junction cell characteristics will be presented here. Thin film cells require substantially less material and have promised the advantage of large area, low cost manufacturing. However, space cell requirements dictate a more complicated trade space. Until recently the focus in space cells has been on efficiency rather than cost. In a several billion-dollar spacecraft the cell cost is relatively small at even a thousand dollars per watt, which is approximately the current array cost. This has primarily been true for spacecraft with power needs from a few hundred watts to tens of kilowatts. However, deployment of a large earth orbiting space power system will require major advances in the photovoltaic array weight, stability in the space environment, efficiency, and ultimately the cost of production and deployment of such arrays. The development of large space power systems, and a host of other proposed space missions, will require the development of viable thin film arrays. The specific power required is almost 40 times what is presently available in commercial arrays. While high efficiency ultra lightweight arrays are not likely to become commercially available anytime soon, advances in thin film photovoltaics may still impact other space technologies (i.e., thin film integrated power supplies) and thus support a broad range of missions in the next decade. Mission examples include micro- air vehicles, ultra-long duration balloons (e.g. Olympus), deep space solar electric propulsion (SEP) "Tug" Array, Mars SEP Array, and Mars surface power outpost. A discussion of the state of the art of thin film cells and their characteristics will be included, particularly focused on their applicability to the space environment. This survey of thin film cells will also include a discussion of inorganic/organic solar cells and their adaptability to the space environment. Enhancements to the efficiency of thin film cells, such as intermediate band quantum dots will be discussed and results presented for current cell configurations.

Bailey, S.; Landis, G.; Raffaelle, R.; Hepp, A.

2002-01-01

289

Turbine sizing of a solar thermal power plant  

NASA Technical Reports Server (NTRS)

Since the insolation is intermittent, thermal energy storage is necessary to extend the time of power generation with solar heat past sunset. There are two approaches to specifying the size of turbine-generator units depending on the system operation. In the first approach, the turbine operates at its full capacity when operating on direct solar heat, and at reduced capacity when operating on collected heat out of energy storage. In the second approach, the turbine will always operate at a uniform level either on derated energy from the receiver or from energy storage. Both of these approaches have certain advantages and disadvantages. In this paper, a simple analysis is outlined and exercised to compare the performance and economics of these two approaches.

Manvi, R.; Fujita, T.

1979-01-01

290

MHD-steam thermal power plant electrical stations with zero stack emission  

Microsoft Academic Search

A system study of a combined cycle MHD-steam thermal power plant electrical station with zero stack emission through recirculation of CO 2, is presented. The design of the MHD generator of the topper is done by means of a quasi-one dimensional optimization model. The technology of the components is conventional. An overall efficiency larger than 40% for power plants with

C. A. Borghi; P. L. Ribani

1996-01-01

291

Thermal memory effects modeling and compensation in RF power amplifiers and predistortion linearizers  

Microsoft Academic Search

Memory effects, which influence the performance of RF power amplifiers (PAs) and predistortion-based linearizers, become more significant and critical in designing these circuits as the modulation signal bandwidth and operation power increase. This paper reports on an attempt to investigate, model, and quantify the contributions of the electrical nonlinearity effects and the thermal memory effects to a PA's distortion generation,

Slim Boumaiza; Fadhel M. Ghannouchi

2003-01-01

292

Power Generator with Thermo-Differential Modules  

NASA Technical Reports Server (NTRS)

A thermoelectric power generator consists of an oven box and a solar cooker/solar reflector unit. The solar reflector concentrates sunlight into heat and transfers the heat into the oven box via a heat pipe. The oven box unit is surrounded by five thermoelectric modules and is located at the bottom end of the solar reflector. When the heat is pumped into one side of the thermoelectric module and ejected from the opposite side at ambient temperatures, an electrical current is produced. Typical temperature accumulation in the solar reflector is approximately 200 C (392 F). The heat pipe then transfers heat into the oven box with a loss of about 40 percent. At the ambient temperature of about 20 C (68 F), the temperature differential is about 100 C (180 F) apart. Each thermoelectric module, generates about 6 watts of power. One oven box with five thermoelectric modules produces about 30 watts. The system provides power for unattended instruments in remote areas, such as space colonies and space vehicles, and in polar and other remote regions on Earth.

Saiz, John R.; Nguyen, James

2010-01-01

293

Maximum power throughput in the multiphase BLDC generator  

Microsoft Academic Search

This paper presents an advanced control technique for maximum power throughput of the multiphase Brushless DC (BLDC) generator of given design. In a generator of given rating, the weight and size of the system affect the fuel consumption directly. Therefore, maximum power density is one of the most important issues in a stand-alone generator. BLDC generator has high power density

H.-W. Lee; T. Kim; M. Ehsani

2004-01-01

294

Competition and Cooperation of Distributed Generation and Power System  

Microsoft Academic Search

Advances in distributed generation technologies together with the deregulation of an electric power industry can lead to a massive introduction of distributed generation. Since most of distributed generation will be interconnected to a power system, coordination and competition between distributed generators and large-scale power sources would be a vital issue in realizing a more desirable energy system in the future.

Masatoshi Miyake; Toshiya Nanahara

2005-01-01

295

Load Frequency Control in Power System with Distributed Generation  

Microsoft Academic Search

This paper proposes a method to improve the load frequency control in a power system with distributed generation (DG). DG is assumed to include photovoltaic generation, wind power generation, fuel cells and etc. In this paper, a simulation is performed using a microgrid model or island model that is composed of a storage system with either wind power generation or

Kazuto Yukita; Takuya Ota; Koji Fujimoto; Yasuyuki Goto; Katuhiro Ichiyanagi

2010-01-01

296

Solar Power Satellite Thermal Control Approach  

NASA Astrophysics Data System (ADS)

The concept of generating solar power in space and transmitting it to earth or any other desired destination such as a planet, moon, or to charge a space vehicle via microwaves, stems from a wide variety of human needs and necessities. It is now a well-known fact that world population increases at a very rapid rate, nearly 80 millions or more per year, and the world-wide energy demand seems to double in the course of the present century. If technology has to advance at the present rate, in phase with high living standards, energy growth must not lag behind. These estimates are based on the population growth rate in the developing countries and the simultaneous increase in per capita energy consumption in these countries, coupled with economical boost. In most of the underdeveloped countries energy needs are of small scales, faraway from the power distribution line and can be very easily satisfied by harnessing solar energy. Furthermore, the Earth temperature has increased by 0.5° to 1° F during the past century. This rise in temperature is believed to have been caused by the use of oil, coal, and natural gas (fossil fuels) for transportation and energy production. Actually, fossil fuel combustion-based power plants are the dominant sources for energy demands. Therefore, increased power production will accelerate the production of greenhouse gases (predominantly CO2). To cope with their energy needs, countries could be engaged in the use of nuclear energy, which could accelerate the diffusion of nuclear arms as a bye- product.

Sacchi, E.; Cassisa, G.; Gottero, M.

2004-12-01

297

CONVERTING ENERGY FROM RECLAIMED HEAT: THERMAL ELECTRIC GENERATOR  

EPA Science Inventory

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

298

Model for Increasing the Power Obtained from a Thermoelectric Generator Module  

NASA Astrophysics Data System (ADS)

We have developed a model for finding the most efficient way of increasing the power obtained from a thermoelectric generator (TEG) module with a variety of operating conditions and limitations. The model is based on both thermoelectric principles and thermal resistance circuits, because a TEG converts heat into electricity consistent with these two theories. It is essential to take into account thermal contact resistance when estimating power generation. Thermal contact resistance causes overestimation of the measured temperature difference between the hot and cold sides of a TEG in calculation of the theoretical power generated, i.e. the theoretical power is larger than the experimental power. The ratio of the experimental open-loop voltage to the measured temperature difference, the effective Seebeck coefficient, can be used to estimate the thermal contact resistance in the model. The ratio of the effective Seebeck coefficient to the theoretical Seebeck coefficient, the Seebeck coefficient ratio, represents the contact conditions. From this ratio, a relationship between performance and different variables can be developed. The measured power generated by a TEG module (TMH400302055; Wise Life Technology, Taiwan) is consistent with the result obtained by use of the model; the relative deviation is 10%. Use of this model to evaluate the most efficient means of increasing the generated power reveals that the TEG module generates 0.14 W when the temperature difference is 25°C and the Seebeck coefficient ratio is 0.4. Several methods can be used triple the amount of power generated. For example, increasing the temperature difference to 43°C generates 0.41 W power; improving the Seebeck coefficient ratio to 0.65 increases the power to 0.39 W; simultaneously increasing the temperature difference to 34°C and improving the Seebeck coefficient ratio to 0.5 increases the power to 0.41 W. Choice of the appropriate method depends on the limitations of system, the cost, and the environment.

Huang, Gia-Yeh; Hsu, Cheng-Ting; Yao, Da-Jeng

2014-06-01

299

A thermal signal generator probe for the study of neural thermal transduction.  

PubMed

The study of thermal transduction in neural tissues has been impeded by the lack of instrumentation able to generate complex, focal temperature variations. Specifically, we are interested in the study of neural thermal transduction within the cornea, with its homogeneous thermal conductivity and avascularity. We present a thermal signal generator probe that is capable of producing arbitrarily shaped bipolar (heating or cooling) thermal swings in a small volume of corneal tissue with which it is in contact. Heating and cooling of the probe tip are achieved by means of a Peltier effect thermoelectric device. The probe temperature, measured directly at the tip, is controlled using closed-loop control circuitry and waveform generation software on a host computer. Response characteristics of thermally sensitive C-fibers were investigated in an in vitro preparation of the rabbit cornea. PMID:7927385

Maluf, N I; McNutt, E L; Monroe, S; Tanelian, D L; Kovacs, G T

1994-07-01

300

INDUCTION HEATING OF CARBON-FIBER COMPOSITES: THERMAL GENERATION MODEL  

EPA Science Inventory

A theory of local and global mechanisms of heat generation and distribution in carbon-fiber-based composites subjected to an alternating magnetic field has been proposed. A model that predicts the strength and distribution of thermal generation through the thickness of carbon-fib...

301

MHD generator scaling analysis for baseload commercial power plants  

Microsoft Academic Search

MHD generator channel scaling analyses have been performed to definitize the effect of generator size and oxygen enrichment on channel performance. These studies have shown that MHD generator channels can be designed to operate efficiently over the range of 250 to 2135 thermal megawatts. The optimum design conditions for each of the thermal inputs were established by investigating various combinations

D. W. Swallom; C. C. P. Pian

1982-01-01

302

High-power test device for package thermal assessment and validation of thermal measurement techniques  

Microsoft Academic Search

This paper describes the structure and thermal behavior of a high-power thermal test chip (up to 200 W\\/cm2) designed for power electronics package assessment, which has also been used for the validation of thermal measurement techniques. In particular, we show two application examples where the proposed device allowed the assessment of different power substrate technologies, and the validation of temperature

Xavier Jordà; Xavier Perpiñà; Miquel Vellvehi; Francesc Madrid; Josep Altet

2010-01-01

303

Transient thermal behavior of high power diode laser arrays  

Microsoft Academic Search

Reliability and lifetime of high power laser arrays are governed by their thermal properties. Thus the understanding of the thermal behavior such as thermal transients as well as the optimization of laser chips and mounting are key features for obtaining improved devices. We present numerical simulations of the active layer temperature employing the finite element method (FEM). Both continuous wave

Roland Puchert; Artur Bärwolff; M. Voss; U. Menzel; J. W. Tomm; J. Luft

2000-01-01

304

High-power broadband organic THz generator.  

PubMed

The high-power broadband terahertz (THz) generator is an essential tool for a wide range of THz applications. Here, we present a novel highly efficient electro-optic quinolinium single crystal for THz wave generation. For obtaining intense and broadband THz waves by optical-to-THz frequency conversion, a quinolinium crystal was developed to fulfill all the requirements, which are in general extremely difficult to maintain simultaneously in a single medium, such as a large macroscopic electro-optic response and excellent crystal characteristics including a large crystal size with desired facets, good environmental stability, high optical quality, wide transparency range, and controllable crystal thickness. Compared to the benchmark inorganic and organic crystals, the new quinolinium crystal possesses excellent crystal properties and THz generation characteristics with broader THz spectral coverage and higher THz conversion efficiency at the technologically important pump wavelength of 800 nm. Therefore, the quinolinium crystal offers great potential for efficient and gap-free broadband THz wave generation. PMID:24220234

Jeong, Jae-Hyeok; Kang, Bong-Joo; Kim, Ji-Soo; Jazbinsek, Mojca; Lee, Seung-Heon; Lee, Seung-Chul; Baek, In-Hyung; Yun, Hoseop; Kim, Jongtaek; Lee, Yoon Sup; Lee, Jae-Hyeok; Kim, Jae-Ho; Rotermund, Fabian; Kwon, O-Pil

2013-01-01

305

Exergetic analysis of a solar thermal power system  

Microsoft Academic Search

This communication presents a second law analysis based on an exergy concept for a solar thermal power system. Basic energy and exergy analysis for the system components (viz. parabolic trough collector\\/receiver and Rankine heat engine, etc.) are carried out for evaluating the respective losses as well as exergetic efficiency for typical solar thermal power systems under given operating conditions. It

Narendra Singh; S. C. Kaushik; R. D. Misra

2000-01-01

306

Integrated EMI\\/thermal design for switching power supplies  

Microsoft Academic Search

In this paper, the EMI and thermal performance of power supplies are taken into consideration in the board layout stage of the design cycle. The approach is based on using existing simulation tools, including parameter extracting software, a circuit simulation tool, and thermal analysis software. A power factor correcting circuit was used for the investigation. Examples are given for performance

Wei Zhang; Fred C. Lee; Dan Y. Chen

2000-01-01

307

Utilizing Radioisotope Power System Waste Heat for Spacecraft Thermal Management  

NASA Technical Reports Server (NTRS)

An advantage of using a Radioisotope Power System (RPS) for deep space or planetary surface missions is the readily available waste heat, which can be used for a number of beneficial purposes including: maintaining electronic components within a controlled temperature range, warming propulsion tanks and mobility actuators, and maintaining liquid propellants above their freezing temperature. Previous missions using Radioisotope Thermoelectric Generators (RTGs) dissipated large quantities of waste heat due to the low efficiency of the thermoelectric conversion technology. The next generation RPSs, such as the 110-Watt Stirling Radioisotope Generator (SRG110) will have higher conversion efficiencies, thereby rejecting less waste heat at a lower temperature and may require alternate approaches to transferring waste heat to the spacecraft. RTGs, with efficiencies of 6 to 7 percent, reject their waste heat at the relatively high heat rejection temperature of 200 C. This is an advantage when rejecting heat to space; however, transferring heat to the internal spacecraft components requires a large and heavy radiator heat exchanger. At the same time, sensitive spacecraft instruments must be shielded from the thermal radiation of the RTG. The SRG110, with an efficiency around 22 percent and 50 C nominal housing surface temperature, can readily transfer the available waste heat directly via heat pipes, thermal straps, or fluid loops. The lower temperatures associated with the SRG110 avoid the chances of overheating other scientific components, eliminating the need for thermal shields. This provides the spacecraft designers more flexibility when locating the generator for a specific mission. A common misconception with high-efficiency systems is that there is not enough waste heat for spacecraft thermal management. This paper will dispel this misconception and investigate the use of a high-efficiency SRG110 for spacecraft thermal management and outline potential methods of waste heat utilization in several conceptual missions (Lunar Rover, Mars Rover, and Titan Lander). The advantages associated with the SRG110 as they relate to ease of assembly, less complex interfaces, and overall mass savings for a spacecraft will be highlighted.

Pantano, David R.; Dottore, Frank; Tobery, E. Wayne; Geng, Steven M.; Schreiber, Jeffrey G.; Palko, Joseph L.

2005-01-01

308

Thermoelectric Analysis for Helical Power Generation Systems  

NASA Astrophysics Data System (ADS)

The performance of a three-dimensional helical thermoelectric generation (TEG) system is examined by exposing it to a temperature difference with hot and cold sources. The helical paths for the two thermal fluids give the TEG device the potential to efficiently convert thermal energy. The characteristic performance of the helical system is numerically analyzed by using the finite-volume method in a compact system. The helical system is compared with a straight system in which all the thermoelectric (TE) elements present equivalent geometry. The difference in the TE performance between the two systems is not significant when the TE surfaces are maintained at constant temperatures. Both the electromotive force and the current in the TEG system increase linearly with the temperature difference ? T applied at the two module surfaces. The current preferentially flows through a main path determined by the geometry of the TE element. The merits of the helical design are its compactness, space saving, and smooth fluid flow due to gravity, compared with the straight system.

Meng, Xiangning; Fujisaka, Takeyuki; Suzuki, Ryosuke O.

2014-06-01

309

A high power spacecraft thermal management system  

NASA Technical Reports Server (NTRS)

This paper describes the design and test results of an ammonia hybrid capillary pumped loop thermal control system. As a hytbrid, the system can operate as either a passive, capillary pumped loop, or, as a mechanically pumped system. The system is comprised of an evaporator section, a condenser section, 10 meters of liquid and vapor transport lines, a mechanical pump, and a reservoir. In the evaporator section, four capillary pumps are each integrated into three cold plates. The mechanical pump is installed in the liquid line and is in series with the capillary pumps. Testing has demonstrated that in the capillary pumped mode, the HPSTM can acquire and transport a total heat load of between 120 W and 24 kW, with a maximum heat flux density of 4.3 W/sq cm in the evaporator section. In the mechanically pumped configuration, a heat acquisition potential of 50 kW (9 W/sq cm heat flux density) has been demonstrated. The hybrid system still retains the proven capillary capabilities of temperature control, heat load sharing and fluid flow control between evaporator plates, rapid power cycling, and pressure priming recovery of deprimed evaporators.

Ku, J.; Kroliczek, E. J.; Mccabe, M. E., Jr.; Benner, S. M.

1988-01-01

310

Development of General-Purpose Software to Analyze the Static Thermal Characteristic of Nuclear Power Plant  

NASA Astrophysics Data System (ADS)

We have developed the general-purpose software by which static thermal characteristic of the power generation system is analyzed easily. This software has the notable features as follows. -It has the new algorithm to solve non-linear simultaneous equations to analyze the static thermal characteristics such as heat and mass balance, efficiencies, etc. of various power generation systems. -It has the flexibility for setting calculation conditions. -It is able to be executed on the personal computer easily and quickly. We ensured that it is able to construct heat and mass balance diagrams of main steam system of nuclear power plant and calculate the power output and efficiencies of the system. Furthermore, we evaluated various heat recovery measures of steam generator blowdown water and found that this software could be a useful operation aid for planning effective changes in support of power stretch.

Nakao, Yoshinobu; Koda, Eiichi; Takahashi, Toru

311

Development of a MEMS-Based Rankine Cycle Steam Turbine For Power Generation: Project Status  

Microsoft Academic Search

This paper summarizes de challenges, prospects, and status of the on-going project to develop a MEMS-based microturbine device that implements a steam Rankine power cycle for portable power generation. First, the device configuration is motivated by a discussion of the unique characteristics of the Rankine cycle. Progress to date on the development of the rotating and thermal subsystems is then

L. G. Fréchette; C. Lee; S. Arslan

2004-01-01

312

Design, Fabrication, and Characterization of CMOS MEMS-Based Thermoelectric Power Generators  

Microsoft Academic Search

This paper presents the design, modeling, fabrication, and characterization of CMOS microelectromechanical-systems-based thermoelectric power generators (TPGs) to convert waste heat into a few microwatts of electrical power. Phosphorus and boron heavily doped polysilicon thin films are patterned and electrically connected to consist thermopiles in the TPGs. To optimize heat flux, the thermal legs are embedded between the top and bottom

Jin Xie; Chengkuo Lee; Hanhua Feng

2010-01-01

313

Piezoelectric power generation for civil infrastructure systems  

NASA Astrophysics Data System (ADS)

Civil infrastructure systems (CIS) employ various small electronic components ranging from temperature and humidity sensors used in buildings to acoustics emission sensors used for damage detection in bridges. Other than solar energy that has already found several applications in CIS; moving loads, surface strain fluctuations, and wind energy available in the vicinity of CIS constitute important sources of energy that can be converted into electricity. This paper focuses on low power generation from these energy sources using piezoelectric transduction. Moving loads caused by travelling vehicles can be used for exciting piezoceramics located on the road. Structural vibrations resulting from various sources such as support motions and interaction of CIS with the surrounding fluid may yield local surface strain fluctuations. Wind energy is available not only due to regular atmospheric flow but also due to the motion of vehicles travelling at relatively high speeds. This paper investigates and formulates (1) the electromechanical moving load problem for slender bridges with a piezoelectric cantilever and with embedded piezoceramics, (2) the problem of piezoelectric power generation from surface strain fluctuations using a piezoceramic patch, and (3) piezoelectric energy harvesting from wind excitation through aeroelastic flutter.

Erturk, A.; Inman, D. J.

2011-03-01

314

Generation mechanism of power line harmonic radiation  

NASA Astrophysics Data System (ADS)

The questions concerning the generation of power line harmonic radiation (PLHR) and magne-tospheric line radiation (MLR) are discussed, including the effective source of high harmonics of 50/60 Hz, and fine dynamic structure of the frequency spectrum of PLHR and MLR. It is shown, that thyristor-based power regulators used by large electrical power consumers produce the periodic sequences of current pulses with duration of about 10 microseconds in a power line. The repetition rate of these pulses is typically 100/120 Hz; the bandwidth is as broad as 100 kHz. For high harmonics of 50/60 Hz, the power line represents an effective traveling-wave (or Beverage) antenna, especially in a frequency range of several kHz corresponding to VLF whistler band in Earth ionosphere and magnetosphere. For the fixed length of the power line, which acts as antenna, radiation directivity diagram in relation to horizon depends of frequency. Hence the spatial separation of whistlers emitted at various frequencies (1-10 kHz in a consid-ered case) is possible, with subsequent propagation of whistlers with different frequencies along different L-shells. Estimations show that the efficiency of power line as travelling-wave antenna can be changed by variations of its load, but not more than twice ("weekend effect"). Since the PLHR can represent the sequence of short electromagnetic bursts, then careful se-lection of frequency-time resolution of the data acquisition equipment is needed. Typically, the time constant of the data recording and processing is too large, and the spectra of PLHR or MLR are characterized by a well-known line structure. At the same time, original bursty structure of PLHR can not be defined. Fine structure of MLR is also discussed. Frequency drift of MLR can be explained by the perturbations of the magnetospheric plasma by intense ULF waves and particle flows affecting the propagation of PLHR. Hence the physical nature of PLHR and MLR is the same, excepting the propagation conditions: MLR is a product of PLHR after passage through the perturbed magnetospheric regions. The work is supported by OFN-15 RAS program, RFBR grants Nos. 09-02-97058-r, 09-02-91052-NCNI-a.

Kostrov, Alexander; Gushchin, Mikhail; Korobkov, Sergei

315

43 CFR 431.6 - Power generation estimates.  

Code of Federal Regulations, 2013 CFR

...INTERIOR GENERAL REGULATIONS FOR POWER GENERATION, OPERATION, MAINTENANCE, AND REPLACEMENT AT THE BOULDER CANYON PROJECT, ARIZONA/NEVADA § 431.6 Power generation estimates. Reclamation shall submit annually on or before April 15 to Western...

2013-10-01

316

Methods and Apparatus for Power Generation Governmental Rights.  

National Technical Information Service (NTIS)

An apparatus for generating an electrical power upon an acceleration of the apparatus is provided. The apparatus includes: a piezoelectric member having at least a portion thereof formed of a piezoelectric material for generating an output power upon an i...

J. S. Rastegar D. Haarhoff

2005-01-01

317

43 CFR 431.4 - Power generation responsibilities.  

Code of Federal Regulations, 2013 CFR

...Act; and third, for power, Reclamation shall release water, make available generating...change in delivery of water, and that Reclamation...resume delivery of water as scheduled. (d...have concerns regarding power generation and...

2013-10-01

318

New method to assess tube support plate clogging phenomena in steam generators of nuclear power plants  

Microsoft Academic Search

Pressurized water reactor steam generators (PWR SGs) are large components whose main function is to cool the fission reactor by extracting the thermal power conveyed by the primary coolant, and thus to produce steam for the turbine generator. Tube support plate (TSP) clogging phenomena may occur in the SG when iron oxide particles carried in the secondary feedwater get unavoidably

D. Bouskela; V. Chip; B. El Hefni; J. M. Favennec; M. Midou; J. Ninet

2010-01-01

319

Development of an HTS hydroelectric power generator for the hirschaid power station  

NASA Astrophysics Data System (ADS)

This paper describes the development and manufacture of a 1.7MW, 5.25kV, 28pole, 214rpm hydroelectric power generator consisting of superconducting HTS field coils and a conventional stator. The generator is to be installed at a hydro power station in Hirschaid, Germany and is intended to be a technology demonstrator for the practical application of superconducting technology for sustainable and renewable power generation. The generator is intended to replace and uprate an existing conventional generator and will be connected directly to the German grid. The HTS field winding uses Bi-2223 tape conductor cooled to about 30K using high pressure helium gas which is transferred from static cryocoolers to the rotor via a bespoke rotating coupling. The coils are insulated with multi-layer insulation and positioned over laminated iron rotor poles which are at room temperature. The rotor is enclosed within a vacuum chamber and the complete assembly rotates at 214rpm. The challenges have been significant but have allowed Converteam to develop key technology building blocks which can be applied to future HTS related projects. The design challenges, electromagnetic, mechanical and thermal tests and results are presented and discussed together with applied solutions.

Fair, Ruben; Lewis, Clive; Eugene, Joseph; Ingles, Martin

2010-06-01

320

Power quality improvement of unbalanced power system with distributed generation units  

Microsoft Academic Search

This paper presents a power electronic system for improving the power quality of the unbalanced distributed generation units in three-phase four-wire system. In the system, small renewable power generation units, such as small PV generator, small wind turbines may be configured as single phase generation units. The random nature of renewable power sources may result in significant unbalance in the

Y Hu; Z Chen; P Excell

2011-01-01

321

High-performance flat-panel solar thermoelectric generators with high thermal concentration  

NASA Astrophysics Data System (ADS)

The conversion of sunlight into electricity has been dominated by photovoltaic and solar thermal power generation. Photovoltaic cells are deployed widely, mostly as flat panels, whereas solar thermal electricity generation relying on optical concentrators and mechanical heat engines is only seen in large-scale power plants. Here we demonstrate a promising flat-panel solar thermal to electric power conversion technology based on the Seebeck effect and high thermal concentration, thus enabling wider applications. The developed solar thermoelectric generators (STEGs) achieved a peak efficiency of 4.6% under AM1.5G (1?kW?m-2) conditions. The efficiency is 7-8 times higher than the previously reported best value for a flat-panel STEG, and is enabled by the use of high-performance nanostructured thermoelectric materials and spectrally-selective solar absorbers in an innovative design that exploits high thermal concentration in an evacuated environment. Our work opens up a promising new approach which has the potential to achieve cost-effective conversion of solar energy into electricity.

Kraemer, Daniel; Poudel, Bed; Feng, Hsien-Ping; Caylor, J. Christopher; Yu, Bo; Yan, Xiao; Ma, Yi; Wang, Xiaowei; Wang, Dezhi; Muto, Andrew; McEnaney, Kenneth; Chiesa, Matteo; Ren, Zhifeng; Chen, Gang

2011-07-01

322

Comparison of advanced engines for parabolic dish solar thermal power plants  

NASA Technical Reports Server (NTRS)

A paraboloidal dish solar thermal power plant produces electrical energy by a two-step conversion process. The collector subsystem is composed of a two-axis tracking paraboloidal concentrator and a cavity receiver. The concentrator focuses intercepted sunlight (direct, normal insolation) into a cavity receiver whose aperture encircles the focal point of the concentrator. At the internal wall of the receiver the electromagnetic radiation is converted to thermal energy. A heat engine/generator assembly then converts the thermal energy captured by the receiver to electricity. Developmental activity has been concentrated on small power modules which employ 11- to 12-meter diameter dishes to generate nominal power levels of approximately 20 kWe. A comparison of advanced heat engines for the dish power module is presented in terms of the performance potential of each engine with its requirements for advanced technology development. Three advanced engine possibilities are the Brayton (gas turbine), Brayton/Rankine combined cycle, and Stirling engines.

Fujita, T.; Bowyer, J. M.; Gajanana, B. C.

1980-01-01

323

43 CFR 418.16 - Using water for power generation.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Using water for power generation. 418.16 Section 418.16 Public...Management § 418.16 Using water for power generation. All use of Project water for power generation must be incidental to releases...

2010-10-01

324

43 CFR 418.16 - Using water for power generation.  

Code of Federal Regulations, 2010 CFR

...2009-10-01 false Using water for power generation. 418.16 Section 418.16 Public...Management § 418.16 Using water for power generation. All use of Project water for power generation must be incidental to releases...

2009-10-01

325

43 CFR 418.16 - Using water for power generation.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Using water for power generation. 418.16 Section 418...Operations and Management § 418.16 Using water for power generation. All use of Project water for power generation must be incidental to...

2013-10-01

326

Effect of Heat Generation of Ultrasound Transducer on Ultrasonic Power Measured by Calorimetric Method  

NASA Astrophysics Data System (ADS)

Ultrasonic power is one of the key quantities closely related to the safety of medical ultrasonic equipment. An ultrasonic power standard is required for establishment of safety. Generally, an ultrasonic power standard below approximately 20 W is established by the radiation force balance (RFB) method as the most accurate measurement method. However, RFB is not suitable for high ultrasonic power because of thermal damage to the absorbing target. Consequently, an alternative method to RFB is required. We have been developing a measurement technique for high ultrasonic power by the calorimetric method. In this study, we examined the effect of heat generation of an ultrasound transducer on ultrasonic power measured by the calorimetric method. As a result, an excessively high ultrasonic power was measured owing to the effect of heat generation from internal loss in the transducer. A reference ultrasound transducer with low heat generation is required for a high ultrasonic power standard established by the calorimetric method.

Uchida, Takeyoshi; Kikuchi, Tsuneo

2013-07-01

327

Voltage control availability of distributed generators in power distribution system  

Microsoft Academic Search

In spite of many profitable or advantageous natures of distributed generators (DGs), for power systems, such badly behaved natures of DGs as (1) unstable power output, (2) voltage problem, (3)harmonics, (4)reverse power flow, etc. also exist. Therefore, it has been always emphasized that the unfavorable effects should not exist when distributed generators are connected to the power system. However, in

K. Nara; S. Ishizu; Y. Mishima

2005-01-01

328

Consequences of lightning strikes on nuclear power generating stations  

Microsoft Academic Search

Direct or indirect lightning strikes have caused reactor trips in nuclear power generating stations. If nuclear power generating stations do not have adequate lightning protection and grounding, such stations may be exposed to greater risk of loss of offsite power, fire, and damage to redundant trains of engineered safeguard equipment. The loss of offsite power is an important initiating event

Narinder K. Trehan

2000-01-01

329

New power politics will determine generation's path  

SciTech Connect

The US power industry's story in 2009 will be all about change, to borrow a now-familiar theme. Though the new administration's policy specifics had not been revealed as this report was prepared, it appears that flat load growth in 2009 will give the new Obama administration a unique opportunity to formulate new energy policy without risking that the lights will go out. New coal projects are now facing increasing difficulties. It looks as though the electricity supply industry will continue to muddle through. It may see an advancement in infrastructure investment, significant new generation or new technology development. It also faces the possibility that policies necessary to achieving those goals will not materialize, for political and economic reasons. 4 figs.

Maize, K.; Neville, A.; Peltier, R.

2009-01-15

330

18 CFR 801.12 - Electric power generation.  

Code of Federal Regulations, 2010 CFR

...generation of electric power at hydro, pumped storage, and thermoelectric generating stations. Increased demands for electric...considerable potential for additional pumped storage and thermoelectric generation. The direct and indirect effects of...

2010-04-01

331

18 CFR 801.12 - Electric power generation.  

Code of Federal Regulations, 2010 CFR

...generation of electric power at hydro, pumped storage, and thermoelectric generating stations. Increased demands for electric...considerable potential for additional pumped storage and thermoelectric generation. The direct and indirect effects of...

2009-04-01

332

Application of Induction Generators in Power Systems. Final Report.  

National Technical Information Service (NTIS)

The application of induction generators in power systems is discussed. The performance of induction generators as function of machine and system parameters and as function of var source control is evaluated and compared with that of synchronous generators...

F. P. de Mello L. N. Hannett J. W. Feltes

1981-01-01

333

Self Excitation and Harmonics in Wind Power Generation.  

National Technical Information Service (NTIS)

Traditional wind turbines are equipped with induction generators. Induction generators are preferred because they are inexpensive, rugged, and require very little maintenance. Unfortunately, induction generators require reactive power from the grid to ope...

E. Muljadi C. P. Butterfield H. Romanowitz R. Yinger

2004-01-01

334

Adaptive Optimal Control of Steam Temperatures for Thermal Power Plants  

Microsoft Academic Search

This paper describes a new adaptive optimal control method for boiler steam temperature control of thermal power plants. Fig. 1 shows a schematic diagram of the adaptive optimal control system. A coal-fired power plant and the automatic plant control (APC) system are assumed to be a single controlled object in order to allow the APC to continue controlling the power

M. Nomura; Y. Sato

1989-01-01

335

Reliability problems in power-generation systems  

SciTech Connect

Some widely publicized incidents have called attention to the problems of reliability, safety, and dependability of power-generation systems, increasing public pressure for additional safety guarantees in power systems. The tendency has been to demand guarantees to zero-risk, an attitude which both augments and is augmented by the slow-growth ethic that has become familiar through the 1970s. It is the suggestion of this discussion paper that, regardless of the merits of different political positions on these issues, it is essential to have a more-precise understanding of the factors that are involved: specifically, that mathematical/statistical tools be developed and made available to potential users in order to quantify the magnitude of the risks inherent in using or failing to use competing technologies. The following are discussed: estimation of very-low-failure probabilities; complex-system reliability methodologies; dependence in failure modes; use of observational-study data; communication of reliability data to nontechnical individuals; semi-parametric procedures; estimating the reliability of man-machine systems; degraded-operation failure modes; pooling data; and accelerated data collection.

Bryson, M.C. (ed.)

1980-01-01

336

Rotor power factor adjustable direct torque control of doubly-fed induction generators for wind power generation  

Microsoft Academic Search

In this paper, direct torque control (DTC) technology of doubly-fed induction generator (DFIG) is analyzed in detail and applied to variable speed constant frequency wind power generation system. A rotor power factor adjustable DTC with maximum wind power tracking is discussed and rotor voltage vectors are obtained based on the look-up table. Based on the stochastic wind which is generated

Yunqian Zhang; Ming Cheng; Jianzhong Zhang; Yun Yang

2009-01-01

337

Diagnostics on the COBRA pulsed power generator  

NASA Astrophysics Data System (ADS)

The COBRA pulsed power generator has a variable current pulse wave form and amplitude (95-180 ns rise time, up to 1 MA peak current). It was designed to study wire array Z pinches and X pinches, including plasma formation, pinch implosion dynamics, and pinch plasma parameters as a function of current rise time. These loads have been studied using an extensive set of diagnostics with spatial and/or temporal resolution. The set of electrical diagnostics on the COBRA generator includes Rogowski coils to monitor the total load current and the current through individual return current posts, and there is also an inductive voltage monitor. A set of extreme ultraviolet and x-ray detectors is used to study the load radiation. Wire array and X pinch plasma formation and dynamics are studied using two-frame, point projection X-pinch x-ray imaging as well as with multiframe laser probing. Flat potassium acid phtalate crystal (KAP), convex, extreme luminosity imaging conical spectrograph, and focusing spectrograph with spatial resolution with mica crystal, pinhole cameras, and a camera with a slit and a step filter set (slip step-wedge camera) can be used in each pulse to monitor the x-ray emission from the X pinch(es) and arrays in several spectral bands.

Shelkovenko, T. A.; Chalenski, D. A.; Chandler, K. M.; Douglass, J. D.; Greenly, J. B.; Hammer, D. A.; Kusse, B. R.; McBride, R. D.; Pikuz, S. A.

2006-10-01

338

Coupled generator and combustor performance calculations for potential early commercial MHD power plants  

NASA Technical Reports Server (NTRS)

A parametric study of the performance of the MHD generator and combustor components of potential early commercial open-cycle MHD/steam power plants is presented. Consideration is given to the effects of air heater system concept, MHD combustor type, coal type, thermal input power, oxygen enrichment of the combustion, subsonic and supersonic generator flow and magnetic field strength on coupled generator and combustor performance. The best performance is found to be attained with a 3000 F, indirectly fired air heater, no oxygen enrichment, Illinois no. 6 coal, a two-stage cyclone combustor with 85% slag rejection, a subsonic generator, and a magnetic field configuration yielding a constant transverse electric field of 4 kV/m. Results indicate that optimum net MHD generator power is generally compressor-power-limited rather than electric-stress-limited, with optimum net power a relatively weak function of operating pressure.

Dellinger, T. C.; Hnat, J. G.; Marston, C. H.

1979-01-01

339

A Thermal and Electrical Analysis of Power Semiconductor Devices  

NASA Technical Reports Server (NTRS)

The state-of-art power semiconductor devices require a thorough understanding of the thermal behavior for these devices. Traditional thermal analysis have (1) failed to account for the thermo-electrical interaction which is significant for power semiconductor devices operating at high temperature, and (2) failed to account for the thermal interactions among all the levels involved in, from the entire device to the gate micro-structure. Furthermore there is a lack of quantitative studies of the thermal breakdown phenomenon which is one of the major failure mechanisms for power electronics. This research work is directed towards addressing. Using a coupled thermal and electrical simulation, in which the drift-diffusion equations for the semiconductor and the energy equation for temperature are solved simultaneously, the thermo-electrical interactions at the micron scale of various junction structures are thoroughly investigated. The optimization of gate structure designs and doping designs is then addressed. An iterative numerical procedure which incorporates the thermal analysis at the device, chip and junction levels of the power device is proposed for the first time and utilized in a BJT power semiconductor device. In this procedure, interactions of different levels are fully considered. The thermal stability issue is studied both analytically and numerically in this research work in order to understand the mechanism for thermal breakdown.

Vafai, Kambiz

1997-01-01

340

Convertor for thermal energy into electrical energy using stirling motor and integral electrical generator  

SciTech Connect

The present invention relates to external combustion engines and more precisely to motors using the Stirling cycle designed to directly convert thermal energy into electrical energy. In accordance with the invention, this transformation is carried out inside a machine which is completely sealed, without a mechanical connection with the outside, in which the power piston drives the moveable part of an electrical generator. In accordance with one preferred embodiment, this electrical generator is a linear alternator. In accordance with a further original feature of the invention, control of the coupling between the displacing piston and the power piston is carried out by using electronic regulation.

Bay-Marcotte, J. L.; Dahan, G. M. I.; Dancette, M.; Jannot, M. A. J.; Le Nabour, M. P.; Pellerin, J. F. G. A.; Rivallin, J.

1985-04-16

341

Thermal management of microwave power heterojunction bipolar transistors  

NASA Astrophysics Data System (ADS)

A comprehensive study of the device layout effects on thermal resistance in thermally-shunted heterojunction bipolar transistors (HBTs) was completed. The thermal resistance scales linearly with emitter dot diameter for single element HBTs. For multiple emitter element devices, the thermal resistance scales with area. HBTs with dot geometrics have lower thermal impedance than bar HBTs with equivalent emitter area. The thermal resistance of a 200 ?m 2 emitter area device was reduced from 266°C/W to 146°C/W by increasing the shunt thickness from 3 ?m to 20 ?m and placing a thermal shunt landing between the fingers. Also, power-added efficiencies at 10 GHz were improved from 30% to 68% by this thermal resistance reduction.

Bozada, C.; Cerny, C.; De Salvo, G.; Dettmer, R.; Ebel, J.; Gillespie, J.; Havasy, C.; Jenkins, T.; Ito, C.; Nakano, K.; Pettiford, C.; Quach, T.; Sewell, J.; Via, G. D.; Anholt, R.

1997-10-01

342

Pulsed-power diode generation of high-power microwaves  

SciTech Connect

The generation of microwave radiation at gigahertz frequencies in high-voltage pulsed-power diodes has been investigated with electromagnetic particle simulations. Pulsed power in the form of a 0.5-1.0 MV, TEM wave is fed to the diode via a 5-cm diameter cylindrical stalk onto which a 30-cm diameter cathode has been mounted. Located some 3 to 5 cm in front of the cathode is a foil anode grid. As the TEM wave propagates between the stalk and an outer cylindrical cage (70-cm diameter) a stream of electrons are emitted off the stalk when the local electric field exceeds 200 kV/cm. This flow is then magnetically insulated and confined by the induced B/sub theta/ fields resulting from the 25- to 50-kA current flow within the stalk. Convex shaping of the cathode surface allows the emitted electrons to form a virtual cathode beyond the grid, then phase bunch to produce narrow bandwidth 1-GHz microwaves over an area equal to that of the cathode. The electromagnetic radiation from the dipole-like electron motions centered on the grid, which follow closely the classical Barkhausen-Kurz description, are reported.

Peratt, A.L.; Mostrom, M.A.; Kwan, T.J.T.; Thode, L.E.

1983-01-01

343

Synchronous island control with significant contribution from wind power generation  

Microsoft Academic Search

Power system islanding is gaining interest as a way to improve power supply security and power quality. This has been facilitated by continuing advancements in communications and digital control. For maximum flexibility, power system islands must be capable of operating with different generation and power network topologies. Furthermore, the implication of high capacities of renewable resources on the ability of

R. J. Best; C. F. Ten; D. J. Morrow; P. A. Crossley

2009-01-01

344

Power system modal analysis considering doubly-fed induction generators  

Microsoft Academic Search

This paper presents a modal analysis of a two machine power system that includes a doubly-fed induction generator (DFIG). The DFIG's model considers rotor flux linkages as dynamic states and stator flux linkages as algebraic variables. Active- and reactive-power controllers are also modeled. Active power is tracked for optimal power extraction from the wind. Using the power system set of

H. A. Pulgar-Painemal; P. W. Sauer

2010-01-01

345

Power generation from nuclear reactors in aerospace applications  

SciTech Connect

Power generation in nuclear powerplants in space is addressed. In particular, the states of technology of the principal competitive concepts for power generation are assessed. The possible impact of power conditioning on power generation is also discussed. For aircraft nuclear propulsion, the suitability of various technologies is cursorily assessed for flight in the Earth's atmosphere. A program path is suggested to ease the conditions of first use of aircraft nuclear propulsion.

English, R.E.

1982-01-01

346

Thermal management methods for compact high power LED arrays  

NASA Astrophysics Data System (ADS)

The package and system level temperature distributions of a high power (>1W) light emitting diode (LED) array has been investigated using numerical heat flow models. For this analysis, a thermal resistor network model was combined with a 3D finite element submodel of an LED structure to predict system and die level temperatures. The impact of LED array density, LED power density, and active versus passive cooling methods on device operation were calculated. In order to help understand the role of various thermal resistances in cooling such compact arrays, the thermal resistance network was analyzed in order to estimate the contributions from materials as well as active and passive cooling schemes. An analysis of thermal stresses and residual stresses in the die are also calculated based on power dissipation and convection heat transfer coefficients. Results show that the thermal stress in the GaN layer are compressive which can impact the band gap and performance of the LEDs.

Christensen, Adam; Ha, Minseok; Graham, Samuel

2007-09-01

347

Solar Thermal Power System for Lunar ISRU Processes  

NASA Astrophysics Data System (ADS)

Lunar In-Situ Resource Utilization (ISRU) processes require thermal energy at various temperatures. Chemical recovery process (pyrolysis, gas-solid reactions, gas-liquid or three-phase reactions and desorption) requires thermal energy at temperatures from 1000 K to 2500 K. Manufacturing processes (hot liquid processing, sinter forming, composite forming, welding, etc.) can be accomplished with thermal energy at temperatures 1200 K ~ 1800 K. For these materials process applications, solar thermal power can be effectively utilized. Physical Sciences Inc. has been developing a innovative solar power system in which solar radiation is collected by the concentrator which transfers the concentrated solar radiation to the optical waveguide transmission line made of low loss optical fiber. In this paper we will present the recent progress of the solar thermal power source being developed at PSI, and discuss potential applications of the system to Lunar ISRU processes.

Nakamura, Takashi; Senior, Constance L.

2005-02-01

348

POWER QUALITY IMPROVEMENT OF PV POWER GENERATION SYSTEMS USING HYBRID FILTER  

Microsoft Academic Search

A hybrid filter constructed of a shunt active filter and distributed passive filters used for power quality improvement in PV power generating systems is presented. The distribution system consists of a photovoltaic power generation system and several dynamic nonlinear loads. The power quality problems of dispersed generation low voltage systems are introduced and the necessity of using hybrid filters instead

Farhad Shahnia; Seyed Hossein Hosseini

349

Impact and limitation of wind power generation in an island power system  

Microsoft Academic Search

The consequences of massive wind generation in a power system depend on many different parameters linked with the generation installation as well as with the power system they are connected with. In the case of island networks, this article presents an assessment method of the maximal admissible quantity of wind generation, regarding power system dynamic constraints. This wind power rate

F. Fesquet; P. Juston; I. Garzulino

2003-01-01

350

Nanostructured thermal batteries with high power density  

Microsoft Academic Search

Nanostructured FeS2 has been synthesized and used as the cathode material in LiSi\\/FeS2 thermal batteries. With the same weight, the nanostructured cathode pellets are 23% thinner than conventional counterparts resulting in 31% increase of pellet density. Therefore, the volume of batteries can be reduced significantly. With the nanostructure, the electrode materials of the thermal batteries react more rapidly and completely

Ming Au

2003-01-01

351

Accelerator Generation and Thermal Separation (AGATS) of Technetium-99m  

ScienceCinema

Accelerator Generation and Thermal Separation (AGATS) of Technetium-99m is a linear electron accelerator-based technology for producing medical imaging radioisotopes from a separation process that heats, vaporizes and condenses the desired radioisotope. You can learn more about INL's education programs at http://www.facebook.com/idahonationallaboratory.

None

2013-05-28

352

Prospectives for China's solar thermal power technology development  

Microsoft Academic Search

China's total installed electrical power capacity reached 700GW by the end of 2007 and is predicted to surpass 900GW in 2010. The rapid increase in energy demand and increasing global warming have both pushed China to change its current electrical power structure where coal power accounts for nearly 75% of the total electric power generation. China has already become the

Zhifeng Wang

2010-01-01

353

Next Generation Thermal Barrier Coatings for the Gas Turbine Industry  

NASA Astrophysics Data System (ADS)

The aim of this study is to develop the next generation of production ready air plasma sprayed thermal barrier coating with a low conductivity and long lifetime. A number of coating architectures were produced using commercially available plasma spray guns. Modifications were made to powder chemistry, including high purity powders, dysprosia stabilized zirconia powders, and powders containing porosity formers. Agglomerated & sintered and homogenized oven spheroidized powder morphologies were used to attain beneficial microstructures. Dual layer coatings were produced using the two powders. Laser flash technique was used to evaluate the thermal conductivity of the coating systems from room temperature to 1200 °C. Tests were performed on as-sprayed samples and samples were heat treated for 100 h at 1150 °C. Thermal conductivity results were correlated to the coating microstructure using image analysis of porosity and cracks. The results show the influence of beneficial porosity on reducing the thermal conductivity of the produced coatings.

Curry, Nicholas; Markocsan, Nicolaie; Li, Xin-Hai; Tricoire, Aurélien; Dorfman, Mitch

2011-01-01

354

Generation of Pulsed Ion BEAMS by an Inductive Storage Pulsed Power Generator.  

National Technical Information Service (NTIS)

A pulsed power generator by an inductive energy storage system is extremely compact and light in comparison with a conventional pulsed power generator, which consists of a Marx bank and a water pulse forming line. A compact and light pulse power generator...

S. Katsuki H. Akiyama S. Maeda

1990-01-01

355

A low power dynamic pseudo random bit generator for test pattern generation  

Microsoft Academic Search

Pseudo random bit generator is widely used in BIST for test pattern generation. Typical pseudo random bit generator adopts linear feedback shift register (LFSR) as its basic circuit. Dynamic LFSR (DLFSR[1]) which has better cryptographic properties with respect to typical LFSR consumes more power. This paper forwards a low power DLFSR (LDLFSR) circuit which achieves comparable performance with less power

Li-gang Hou; Xiao-hong Peng; Wu-chen Wu

2008-01-01

356

Economic generation direction for power system static voltage stability  

Microsoft Academic Search

This paper compares various generation direction methods in static voltage stability study in power systems. A new approach, namely economic generation direction (EGD) approach, is proposed to find the generation direction that minimizes the total operating cost. The proposed method is compared with conventional and the most recent generation direction methods, namely maximum loading margin and optimal generation direction methods,

A. Sode-Yome; N. Mithulananthan; Kwang Y. Lee

2006-01-01

357

Thermal design for the high-power LED lamp  

NASA Astrophysics Data System (ADS)

This paper summarizes different kinds of heat sinks on the market for high power LED lamps. Analysis is made on the thermal model of LED, PCB and heat sink separately with a simplified mode provided. Two examples of simulation are illustrated as a demonstration for the thermal simulation as guidance for LED lamp design.

Xiaogai, Tian; Wei, Chen; Jiyong, Zhang

2011-01-01

358

Thermal design of high-power LED package and system  

NASA Astrophysics Data System (ADS)

In this paper we present thermal analysis of three kinds of ceramic package designs for high power LEDs and thermal characterization of high power LED array system. The analysis was made by transient thermal measurement and thermal simulation using the finite volume method (FVM). For the package design, thermal behaviors, as are described in thermal resistance, of the three packaging designs were compared and evaluated as functions of bulk thermal resistance, spreading resistance, and surface roughness. The deviation between the simulated results and measured data were attributed to the different surface roughness in the interfaces between the packaging components. For the system design, the emphasis is placed upon the investigation of junction temperature rise of LED array for a limited range of boundary conditions which include design effect of heat pipe, convection condition, and ambient temperature. It was found out that the measured junction temperatures and thermal resistance of LED array are increased with the input power and ambient temperature and decreased with the air velocity. An analytical thermal model analogous with an equivalent parallel circuit system was proposed and was verified by comparison with experimental data.

Shin, Moo Whan

2006-10-01

359

Thermal Energy Corporation Combined Heat and Power Project  

SciTech Connect

To meet the planned heating and cooling load growth at the Texas Medical Center (TMC), Thermal Energy Corporation (TECO) implemented Phase 1 of a Master Plan to install an additional 32,000 tons of chilled water capacity, a 75,000 ton-hour (8.8 million gallon) Thermal Energy Storage (TES) tank, and a 48 MW Combined Heat and Power (CHP) system. The Department of Energy selected TMC for a $10 million grant award as part of the Financial Assistance Funding Opportunity Announcement, U.S. Department of Energy National Energy Technology, Recovery Act: Deployment of Combined Heat and Power (CHP) Systems, District Energy Systems, Waste Energy Recovery Systems, and Efficiency Industrial Equipment Funding Opportunity Number: DE-FOA-0000044 to support the installation of a new 48 MW CHP system at the TMC located just outside downtown Houston. As the largest medical center in the world, TMC is home to many of the nationâ??s best hospitals, physicians, researchers, educational institutions, and health care providers. TMC provides care to approximately six million patients each year, and medical instruction to over 71,000 students. A medical center the size of TMC has enormous electricity and thermal energy demands to help it carry out its mission. Reliable, high-quality steam and chilled water are of utmost importance to the operations of its many facilities. For example, advanced medical equipment, laboratories, laundry facilities, space heating and cooling all rely on the generation of heat and power. As result of this project TECO provides this mission critical heating and cooling to TMC utilizing a system that is both energy-efficient and reliable since it provides the capability to run on power independent of the already strained regional electric grid. This allows the medical center to focus on its primary mission â?? providing top quality medical care and instruction â?? without worrying about excessive energy costs or the loss of heating and cooling due to the risk of power outages. TECOâ??s operation is the largest Chilled Water District Energy System in the United States. The company used DOEâ??s funding to help install a new high efficiency CHP system consisting of a Combustion Turbine and a Heat Recovery Steam Generator. This CHP installation was just part of a larger project undertaken by TECO to ensure that it can continue to meet TMCâ??s growing needs. The complete efficiency overhaul that TECO undertook supported more than 1,000 direct and indirect jobs in manufacturing, engineering, and construction, with approximately 400 of those being jobs directly associated with construction of the combined heat and power plant. This showcase industrial scale CHP project, serving a critical component of the nationâ??s healthcare infrastructure, directly and immediately supported the energy efficiency and job creation goals established by ARRA and DOE. It also provided an unsurpassed model of a district energy CHP application that can be replicated within other energy intensive applications in the industrial, institutional and commercial sectors.

E. Bruce Turner; Tim Brown; Ed Mardiat

2011-12-31

360

Challenges and Opportunities for Fuel Cells in Stationary Power Generation  

Microsoft Academic Search

Fuel cell power systems are considered attractive for a wide range of stationary power generation applications including residential, commercial, and industrial distributed generation, as well as large utility power plants. The current interest in fuel cell systems stems from their potential for high efficiency (lower heating value (LHV) efficiencies of 35–70 percent, depending on technology and system capacity). In addition,

Suresh Sriramulu; Jason Targoff; Stephen Lasher; Eric Carlson; Robert Zogg

2005-01-01

361

Flexibility for CGCC power generation; LPM energy storage  

Microsoft Academic Search

Energy storage systems have long been used to increase the utilization of capital-intensive power generating assets. Conventional energy storage technologies - such as pumped hydroelectric, compressed air, and batteries - take excess electric power from baseload generating units, store it, and deliver power during peak demand periods. While these technologies share a common objective, they each have their own characteristics

E. R. Osterstock; J. Klosek; J. C. Sorenson

1991-01-01

362

Accelerated electromechanical dynamic modelling of a distributed generation power pack  

Microsoft Academic Search

Distributed diesel generation is widely used to supply electric power in a variety of applications. These applications range from backup power supply systems and combined wind- diesel generation to providing power in places where grid connection is either technically impractical or financially uneconomic. Modelling and optimisation of such systems as a whole is extremely difficult due to the long-time load

C. I. Hill; P. Zanchetta; S. V. Bozhko

2011-01-01

363

Distributed Generation: towards an effective contribution to power system security  

Microsoft Academic Search

With a continuously increasing penetration in power system, the impact of dispersed generation is getting higher and higher. This paper deals with the contribution of DG to power system security. It focuses more precisely on its behavior in case of severe frequency disturbances and shows how distributed generation can provide an active contribution to power system security. The UCTE represents

B. Meyer

2007-01-01

364

Direct charge radioisotope activation and power generation  

DOEpatents

An activator has a base on which is mounted an elastically deformable micromechanical element that has a section that is free to be displaced toward the base. An absorber of radioactively emitted particles is formed on the base or the displaceable section of the deformable element and a source is formed on the other of the displaceable section or the base facing the absorber across a small gap. The radioactive source emits charged particles such as electrons, resulting in a buildup of charge on the absorber, drawing the absorber and source together and storing mechanical energy as the deformable element is bent. When the force between the absorber and the source is sufficient to bring the absorber into effective electrical contact with the source, discharge of the charge between the source and absorber allows the deformable element to spring back, releasing the mechanical energy stored in the element. An electrical generator such as a piezoelectric transducer may be secured to the deformable element to convert the released mechanical energy to electrical energy that can be used to provide power to electronic circuits.

Lal, Amit (Madison, WI); Li, Hui (Madison, WI); Blanchard, James P. (Madison, WI); Henderson, Douglass L. (Madison, WI)

2002-01-01

365

Nanostructured thermal batteries with high power density  

NASA Astrophysics Data System (ADS)

Nanostructured FeS 2 has been synthesized and used as the cathode material in LiSi/FeS 2 thermal batteries. With the same weight, the nanostructured cathode pellets are 23% thinner than conventional counterparts resulting in 31% increase of pellet density. Therefore, the volume of batteries can be reduced significantly. With the nanostructure, the electrode materials of the thermal batteries react more rapidly and completely during discharge resulting with a remarkable increase of energy output. The discharge tests show that the energy density of the nanostructured thermal batteries is two times higher (109 J/g) than the conventional counterpart (58 J/g). The nanostructured pellets are more robust mechanically than the conventional counterparts that could increase productivity and lower manufacturing cost.

Au, Ming

366

Optimal power flow with consideration of wind generation cost  

Microsoft Academic Search

This paper discusses the solution of optimal power flow incorporating wind generation cost. A new model of wind generation cost is presented based on the probability distribution of wind farm power output. In this model, the wind farm generation cost consists of two components: the reserve capacity cost and the environmental benefit loss. Both of the two components could be

L. B. Shi; C. Wang; L. Z. Yao; L. M. Wang; Y. X. Ni; B. Masoud

2010-01-01

367

Distributed generation power system modeling in nonlinear Hamiltonian form  

Microsoft Academic Search

Distributed generation has dramatically changed the structure of modern power systems. In this structure, power electronic devices are extensively used providing the possibility of new control strategies in the distribution network. To implement these strategies, a complete dynamic analysis of the distributed generation system is needed. In this paper, exploiting a common feature of almost all the distributed generation components

Konstantinos F. Krommydas; George C. Konstantopoulos; Michael K. Bourdoulis; Antonio T. Alexandridis

2012-01-01

368

Interconnection of Distributed Generators and Their Influences on Power System  

Microsoft Academic Search

The increasing penetration of distributed generation (DG) in the power system creates new challenges and problems for network operators. The generation of electricity comes to a new era with a variety of small-scale technologies from conventional generators to sources connected to grids through power electronic converters. The impact of different technologies and installed capacity on a distribution system changes from

Vu Van Thong; Johan Driesen; Ronnie Belmans

369

13. INTERIOR OF POWER PLANT LOOKING EASTNORTHEAST. 1925 GE GENERATOR ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

13. INTERIOR OF POWER PLANT LOOKING EAST-NORTHEAST. 1925 GE GENERATOR IN FOREGROUND, WITH C. 1910 GENERATOR COVER IN BACKGROUND. STEEL FRAME SUPPORTS HOISTING MECHANISM USED TO MOVE, REPAIR, OR REPLACE GENERATORS. - Potomac Power Plant, On West Virginia Shore of Potomac River, about 1 mile upriver from confluence with Shenandoah River, Harpers Ferry, Jefferson County, WV

370

Coal and Coal/Biomass-Based Power Generation  

EPA Science Inventory

For Frank Princiotta's book, Global Climate Change--The Technology Challenge Coal is a key, growing component in power generation globally. It generates 50% of U.S. electricity, and criteria emissions from coal-based power generation are being reduced. However, CO2 emissions m...

371

Integrated engine-generator concept for aircraft electric secondary power  

NASA Technical Reports Server (NTRS)

The integrated engine-generator concept of locating an electric generator inside an aircraft turbojet or turbofan engine concentric with, and driven by, one of the main engine shafts is discussed. When properly rated, the generator can serve as an engine starter as well as a generator of electric power. The electric power conversion equipment and generator controls are conveniently located in the aircraft. Preliminary layouts of generators in a large engine together with their physical sizes and weights indicate that this concept is a technically feasible approach to aircraft secondary power.

Secunde, R. R.; Macosko, R. P.; Repas, D. S.

1972-01-01

372

Non-Equilibrium Plasma MHD Electrical Power Generation at Tokyo Tech  

NASA Astrophysics Data System (ADS)

This paper reviews the recent activities on radio-frequency (rf) electromagnetic-field-assisted magnetohydrodynamic (MHD) power generation experiments at the Tokyo Institute of Technology. An inductively coupled rf field (13.56 MHz) is continuously supplied to the disk-shaped Hall-type MHD generator. The first part of this paper describes a method of obtaining increased power output from a pure Argon plasma MHD power generator by incorporating an rf power source to preionize and heat the plasma. The rf heating enhances ionization of the Argon and raises the temperature of the free electron population above the nominally low 4500 K temperatures obtained without rf heating. This in turn enhances the plasma conductivity making MHD power generation feasible. We demonstrate an enhanced power output when rf heating is on approximately 5 times larger than the input power of the rf generator. The second part of this paper is a demonstration of a physical phenomenon of the rf-stabilization of the ionization instability, that had been conjectured for some time, but had not been seen experimentally. The rf heating suppresses the ionization instability in the plasma behavior and homogenizes the nonuniformity of the plasma structures. The power-generating performance is significantly improved with the aid of the rf power under wide seeding conditions. The increment of the enthalpy extraction ratio of around 2% is significantly greater than the fraction of the net rf power, that is, 0.16%, to the thermal input.

Murakami, T.; Okuno, Y.; Yamasaki, H.

2008-02-01

373

Thermal, hydraulic, and corrosion aspects of PWR steam generator problems  

SciTech Connect

Two types of PWR steam generators are in use: recirculating steam generators (RSGs) and once-through steam generators (OTSGs). Most of the units and vertical and this review will be limited to vertical units. Some of these steam generators have operated with a minimum of problems while other steam generator designs have experienced a variety of corrosion and mechanically induced problems. The discussion will focus more on the designs that have experienced problems and the effort expended to correct them. Corrosion problems include denting, wastage, intergranular attack, stress corrosion cracking, corrosion fatigue, pitting on the outside surfaces of the tubes, and stress corrosion cracking the inner surfaces of the tubes. Mechanical concerns have included water hammer, thermal stratification in feed-water pipes, fretting and wear of the tubes caused by excessive tube vibration, and erosion-corrosion. These problems have caused unscheduled outages and expensive repairs.

Green, S.J.

1988-01-01

374

Design of Commercial Solar Updraft Tower Systems—Utilization of Solar Induced Convective Flows for Power Generation  

Microsoft Academic Search

A solar updraft tower power plant - sometimes also called 'solar chimney' or just 'solar tower' - is a solar thermal power plant utilizing a combination of solar air collector and central updraft tube to generate a solar induced convective flow which drives pressure staged turbines to generate electricity. The paper presents theory, practical experience, and economy of solar updraft

Jo?rg Schlaich; Rudolf Bergermann; Wolfgang Schiel; Gerhard Weinrebe

2005-01-01

375

Stochastic analysis and maintenance planning of the ash handling system in the thermal power plant  

Microsoft Academic Search

This paper discusses stochastic analysis of the ash handling system in a thermal power plant. The system consists of four subsystems Ai, Bj, C and Dk in series, with three possible states: good, reduced and failed. Failure and repair rates for each subsystem are taken to be constants. Using a probabilistic approach, the differential equations are generated and the expression

Navneet Arora; Dinesh Kumar

1997-01-01

376

Thermal expansion of slag and fly ash from coal gasification in IGCC power plant  

Microsoft Academic Search

Integrated gasification in combined cycle (IGCC) is an electrical power generation system which is characterized to be a clean coal technology different than conventional process in combustible treatment. IGCC process gives rise to inorganic solid wastes in the form of vitreous slag and fly ashes with singular thermal properties. The gasification of the fuel takes place at high temperature and

M. Aineto; A. Acosta; J. Ma. Rincón; M. Romero

2006-01-01

377

Diagnosis of Thermal Efficiency of Combined Cycle Power Plants Using Optical Torque Sensors  

Microsoft Academic Search

A new optical torque measurement method is proposed for diagnosis of thermal efficiency of combined cycle power plants. In the case that the plant comprises a steam turbine and a gas turbine, both of which are connected to the same generator, it is difficult to identify which turbine causes deterioration of performance when the plant efficiency is reduced. Therefore, an

Shuichi Umezawa

2005-01-01

378

Diagnosis of Thermal Efficiency of Advanced Combined Cycle Power Plants Using Optical Torque Sensors  

Microsoft Academic Search

A new optical torque measurement method was applied to diagnosis of thermal efficiency of advanced combined cycle, i.e. ACC, plants. Since the ACC power plant comprises a steam turbine and a gas turbine and both of them are connected to the same generator, it is difficult to identify which turbine in the plant deteriorates the performance when the plant efficiency

Shuichi Umezawa

2006-01-01

379

Ames Lab 101: Next Generation Power Lines  

SciTech Connect

Ames Laboratory scientist Alan Russell discusses the need to develop new power lines that are stronger and more conductive as a way to address the problem of the nation's aging and inadequate power grid.

Russell, Alan

2010-01-01

380

Ames Lab 101: Next Generation Power Lines  

ScienceCinema

Ames Laboratory scientist Alan Russell discusses the need to develop new power lines that are stronger and more conductive as a way to address the problem of the nation's aging and inadequate power grid.

Russell, Alan

2012-08-29

381

Solar Thermal Power System for Oxygen Production from Lunar Regolith  

NASA Astrophysics Data System (ADS)

This paper discusses the development of a solar thermal power system for oxygen production from lunar regolith. In this solar thermal system, solar radiation is collected by the concentrator array which transfers the concentrated solar radiation to the optical waveguide (OW) transmission line made of low loss optical fibers. The OW transmission line directs the solar radiation to the thermal receiver for thermochemical processing of lunar regolith for oxygen production on the lunar surface. We report the results pertaining to: (1) component development status; (2) regolith melting capability; (3) system efficiency; and (4) system weight. Conceptual designs of the solar thermal system for two lunar oxygen production processes are presented.

Nakamura, Takashi; van Pelt, Aaron D.; Gustafson, Robert J.; Clark, Larry

2008-01-01

382

Characteristics of carbon nanotubes based micro-bubble generator for thermal jet printing.  

PubMed

We propose a conceptional thermal printhead with dual microbubble generators mounted parallel in each nozzle chamber, where multiwalled carbon nanotubes are adopted as heating elements with much higher energy efficiency than traditional approaches using noble metals or polysilicon. Tailing effect of droplet can be excluded by appropriate control of grouped bubble generations. Characteristics of the corresponding micro-fabricated microbubble generators were comprehensively studied before the formation of printhead. Electrical properties of the microheaters on glass substrate in air and performance of bubble generation underwater focusing on the relationships between input power, device resistance and bubble behavior were probed. Proof-of-concept bubble generations grouped to eliminate the tailing effect of droplet were performed indicating precise pattern with high resolution could be realized by this kind of printhead. Experimental results revealed guidance to the geometric design of the printhead as well as its fabrication margin and the electrical control of the microbubble generators. PMID:22408940

Zhou, Wenli; Li, Yupeng; Sun, Weijun; Wang, Yunbo; Zhu, Chao

2011-12-01

383

Dynamic Simulation of Closed Brayton Cycle Solar Thermal Power System  

Microsoft Academic Search

The work process of Closed Brayton Cycle Solar Thermal Power System is a dynamic process and the periodical change of eclipse and sun period will influence the system performance. In order to study the dynamic characteristic of the system, a dynamic model is proposed using lumped method and the dynamic simulations of space solar-dynamic power system with the electrical output

Yuting WU; Jianxun REN; Zengyuan GUO; Chongfang MA

384

A simulation model for solar thermal electric power systems  

Microsoft Academic Search

The paper discusses SIMSTEPS, a generalized computer simulation model for the dynamic performance analysis of solar thermal electric power systems. The current subsystem models contained in the program are briefly described, including those for the Fresnel reflectors, the absorber, the steam accumulator, and the steam turbine. The simulation of a 12-MW distributed power plant is outlined, and results are presented

G. R. Johnson; N. El Gabalawi

1975-01-01

385

Fuel Procurement for First Generation Fusion Power Plants.  

National Technical Information Service (NTIS)

The provision of deuterium, tritium, lithium and beryllium fuel materials for fusion power plants is examined in this document. Possible fusion reactions are discussed for use in first generation power plants. Requirements for fuel materials are considere...

B. F. Gore P. L. Hendrickson

1976-01-01

386

Power performance of US space radioisotope thermoelectric generators  

Microsoft Academic Search

Since 1961, the United States has flown 41 radioisotope thermoelectric generators (RTGs) and one reactor to provide power for 25 space power systems. Thirty-eight of these nuclear power sources on 22 space systems are still in space or on other planetary bodies. This paper summarizes the design and power performance of each of the basic RTG types that have been

Gary L. Bennett; E. A. Skrabek

1996-01-01

387

Nuclear reactor magnetohydrodynamic power generator for directed energy weapons  

Microsoft Academic Search

The SDI electrical power requirements for directed energy weapons (DEW) may range from tens of megawatts to over hundreds of megawatts. For this application, where the power requirement is continuous for a period to time ranging from tens to hundreds or thousands of seconds, nuclear magnetohydrodynamic (MHD) power generation provides an attractive method for producing the required power levels. The

Daniel W. Swallom

1987-01-01

388

Limits to solar power conversion efficiency with applications to quantum and thermal systems  

NASA Technical Reports Server (NTRS)

An analytical framework is presented that permits examination of the limit to the efficiency of various solar power conversion devices. Thermodynamic limits to solar power efficiency are determined for both quantum and thermal systems, and the results are applied to a variety of devices currently considered for use in space systems. The power conversion efficiency for single-threshold energy quantum systems receiving unconcentrated air mass zero solar radiation is limited to 31 percent. This limit applies to photovoltaic cells directly converting solar radiation, or indirectly, as in the case of a thermophotovoltaic system. Photoelectrochemical cells rely on an additional chemical reaction at the semiconductor-electrolyte interface, which introduces additional second-law demands and a reduction of the solar conversion efficiency. Photochemical systems exhibit even lower possible efficiencies because of their relatively narrow absorption bands. Solar-powered thermal engines in contact with an ambient reservoir at 300 K and operating at maximum power have a peak conversion efficiency of 64 percent, and this occurs for a thermal reservoir at a temperature of 2900 K. The power conversion efficiency of a solar-powered liquid metal magnetohydrodydnamic generator, a solar-powered steam turbine electric generator, and an alkali metal thermoelectric converter is discussed.

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

1983-01-01

389

An immune-tabu hybrid algorithm for thermal unit commitment of electric power systems  

Microsoft Academic Search

This paper presents a new method based on an immune-tabu hybrid algorithm to solve the thermal unit commitment (TUC) problem\\u000a in power plant optimization. The mathematical model of the TUC problem is established by analyzing the generating units in\\u000a modern power plants. A novel immune-tabu hybrid algorithm is proposed to solve this complex problem. In the algorithm, the\\u000a objective function

Wei Li; Hao-yu Peng; Wei-hang Zhu; De-ren Sheng; Jian-hong Chen

2009-01-01

390

Science 101: How do windmills generate power?  

NSDL National Science Digital Library

This is a timely question given that you can now buy your own windmill (or more correctly, wind turbine ) for residential use. More on that later. Using windmills to generate electricity makes sense once you understand how we generate electricity.

Robertson, William C.

2009-07-01

391

Characterization of Thermal Arc Generator RB3 Flows by Laser Absorption Spectroscopy and Pitot Probe  

Microsoft Academic Search

The thermal arc generator RB3 flows were characterized by laser absorption spectroscopy and Pitot probe measurement. Firstly, translational temperature and flow velocity distributions in an argon flow were deduced from measured absorption profile of ArI 772.42 nm. The averaged specific enthalpy and plasma power for TPS test region was estimated as 3.72±0.48 MJ\\/kg, 1.77±0.68 kW, respectively. Next, an air flow

Makoto MATSUI; Hiroki TAKAYANAGI; Andreas KNAPP; Georg HERDRICH; Kimiya KOMURASAKI; Yoshihiro ARAKAWA; Monika AUWETER-KURTZ

2008-01-01

392

Secondary electric power generation with minimum engine bleed  

NASA Technical Reports Server (NTRS)

Secondary electric power generation with minimum engine bleed is discussed. Present and future jet engine systems are compared. The role of auxiliary power units is evaluated. Details of secondary electric power generation systems with and without auxiliary power units are given. Advanced bleed systems are compared with minimum bleed systems. A cost model of ownership is given. The difference in the cost of ownership between a minimum bleed system and an advanced bleed system is given.

Tagge, G. E.

1983-01-01

393

SHORT-TERM WIND FORECASTING TECHNIQUES FOR POWER GENERATION  

Microsoft Academic Search

Abstract This paper describes wind prediction for power,generation purposes and introduces a novel approach,- application of an Adaptive Neural Fuzzy Inference System (ANFIS)to forecasting a wind time series. Wind power currently is the fastest growing power generation sector in the world. However, wind power is intermittent and can cause system instability in a deregulated system. A report on Australia’s Renewable

Cameron Potter; Martin Ringrose; Michael Negnevitsky

394

When The Power Goes Out, Keep Your Generator Outside  

MedlinePLUS

WHEN THE POWER GOES OUT, KEEP YOUR GENERATOR OUTSIDE Portable back-up generators produce the poison gas carbon monoxide (CO). CO is an odorless, colorless gas that kills without warning. It claims the lives of ...

395

Thermal imaging of microwave power GaAs-FET with scanning thermal nanoprobe  

NASA Astrophysics Data System (ADS)

Application of a new thermal nano-probe based on the changes of electrical resistivity of a nanometer-sized filament with temperature has been presented for the thermal imaging of microwave power active devices. The filament is integrated into an atomic force scanning probe piezoresistive type cantilever. The novel thermal probe has a spatial resolution better than 80 nm and a thermal resolution of the order of 10-3 K [1]. The measurements have been successfully performed on a 30 fingers GaAs-MESFET with a maximum power dissipation of 2.5 W. The microwave transistor has been implemented in a circuit in such a way to prevent the undesired microwave oscillations. In this case the power dissipation is equal to the dc power input. The near-field measurements have been compared with three-dimensional finite element simulations. A good agreement between simulations and measurements is achieved.

Joodaki, Mojtaba; Janus, Pawel; Gotszalk, Teodor; Kompa, Günter; Edinger, Klaus; Rangelow, Ivo W.

2002-09-01

396

Solar driven liquid metal MHD power generator  

Microsoft Academic Search

A solar energy collector focuses solar energy onto a solar oven which is attached to a mixer which in turn is attached to the channel of a MHD generator. Gas enters the oven and a liquid metal enters the mixer. The gas\\/liquid metal mixture is heated by the collected solar energy and moves through the MHD generator thereby generating electrical

J. H. Lee; F. Hohl

1983-01-01

397

Underwater vehicle propulsion and power generation  

NASA Technical Reports Server (NTRS)

An underwater vehicle includes a shaft with a propeller disposed thereon; a generator/motor having a stator and a rotor, the rotor being operable to rotate with the propeller; at least one energy storage device connected to the generator/motor; and a controller for setting the generator/motor in a charge mode, a propulsion mode and an idle mode.

Jones, Jack A. (Inventor); Chao, Yi (Inventor)

2008-01-01

398

Study of Low Voltage Ride Through Performance for Wind Power Generation with Doubly Fed Induction Generator  

NASA Astrophysics Data System (ADS)

Recently, the introduction of wind power generation is increasing rapidly. The ratio of wind power generation to the capacity of a total generation is getting higher and higher. When the phase-to-phase fault occurs in the power system, the frequency of power system is lower due to disconnecting of the wind power generation with doubly fed induction generator (DFIG). Therefore, the power system might become unstable. This paper describes the LVRT (low voltage ride through) performance improvement scheme of the wind power generation with DFIG. The wind power generation is disconnected from the grid in case of the power system fault. It is independently in operation from the grid by controlling of the inverter equipped in the generation. After clearance of the power system fault, the wind power generation is immediately re-connected to the grid. As a result, instability in the power system disappears. The performance of LVRT is confirmed by using simulation software PSCAD/EMTDC. The simulation result shows an excellent result to the three-phase short-circuit fault of the voltage dip 100%.

Hirawata, Ryoya; Kai, Takaaki

399

Impacts of distributed generation on power system transient stability  

Microsoft Academic Search

It is expected that increasing amounts of new generation technologies will be connected to electrical power systems in the near future. Most of these technologies are of considerably smaller scale than conventional synchronous generators and are therefore connected to distribution grids. Further, many are based on technologies different from the synchronous generator, such as the squirrel cage induction generator and

J. G. Slootweg; W. L. Kling

2002-01-01

400

Worker health and safety in solar thermal power systems. III. Thermal energy storage subsystems  

Microsoft Academic Search

The effects of the use of thermal energy storage (TES) subsystems in solar thermal power systems (STPS) on operating failures and on worker health and safety are examined. Revelant near- and medium-term designs for TES subsystems are reviewed. Generic failure events are considered by an event tree methodology. Three generic categories of initiating events are identified which can lead to

A. Z. Ullman; B. B. Sokolow; J. Daniels; P. Hurt

1979-01-01

401

Worker health and safety in solar thermal power systems. III. Thermal energy storage subsystems  

Microsoft Academic Search

The effects of the use of thermal energy storage (TES) subsystems in solar thermal power systems (STPS) on operating failures and on worker health and safety are examined. Relevant near- and medium-term designs for TES subsystems are reviewed. Generic failure events are considered by an event tree methodology. Three generic categories of initiating events are identified which can lead to

A. Z. Ullman; B. B. Sokolow; J. Daniels; P. Hurt

1979-01-01

402

The thermal effects of cooling system of a thermal power plant on photosynthesis of marine phytoplankton  

Microsoft Academic Search

The activity of photosynthesis and the contents of chlorophylla and pheo-pigments were compared in the samples of the intake and effluent seawater of Owase-Mita Thermal Power Plant and in the seawater samples in the Yoshimi Bay before and after heat treatment. At Owase-Mita Thermal Power Plant, after passage of sea water through the cooling system chlorophylla content reduced to about

Kaoru Takesue; Arao Tsuruta

1978-01-01

403

The application of simulation modeling to the cost and performance ranking of solar thermal power plants  

NASA Technical Reports Server (NTRS)

Small solar thermal power systems (up to 10 MWe in size) were tested. The solar thermal power plant ranking study was performed to aid in experiment activity and support decisions for the selection of the most appropriate technological approach. The cost and performance were determined for insolation conditions by utilizing the Solar Energy Simulation computer code (SESII). This model optimizes the size of the collector field and energy storage subsystem for given engine generator and energy transport characteristics. The development of the simulation tool, its operation, and the results achieved from the analysis are discussed.

Rosenberg, L. S.; Revere, W. R.; Selcuk, M. K.

1981-01-01

404

Investigation of thermal storage and steam generator issues  

SciTech Connect

A review and evaluation of steam generator and thermal storage tank designs for commercial nitrate salt technology showed that the potential exists to procure both on a competitive basis from a number of qualified vendors. The report outlines the criteria for review and the results of the review, which was intended only to assess the feasibility of each design, not to make a comparison or select the best concept.

Not Available

1993-08-01

405

Optimal reactive power flow with distributed generating plants in electric power distribution systems  

Microsoft Academic Search

This paper presents the solution of reactive power flow optimization for electric power distribution systems integrating with distributed generating (Distributed Generator: DG) plants which can support daily load demand. To reduce the total energy losses of the entire system, transformer tap and reactive power injection from available reactive power source are required. The setting of variables based on a particular

U. Leeton; T. Ratniyomchai; T. Kulworawanichpong

2010-01-01

406

The impact of large scale wind power generation on power system oscillations  

Microsoft Academic Search

Increasing amounts of wind turbines are connected to electrical power systems. This affects many aspects of their operation and behaviour. In this paper, the impact of large scale wind power generation on power system oscillations is treated. The three main types of power system oscillations, namely oscillations of a group of generators against a strong system and intra- and inter-area

J. G. Slootweg; W. L. Kling

2003-01-01

407

A MultiFunctional Power Electronic Converter in Distributed Generation Power Systems  

Microsoft Academic Search

This paper presents a power electronic converter which is used as an interface for a distributed generation unit\\/energy storage device, and also functioned as an active power compensator in a hybrid compensation system. The operation and control of the converter have been described. An example of the converter interfacing a wind power generation unit is also given. The power electronic

Z. Chen; F. Blaabjerg; J. K. Pedersen

2005-01-01

408

Thermal management of next-generation contact-cooled synchrotron x-ray mirrors  

SciTech Connect

In the past decade, several third-generation synchrotrons x-ray sources have been constructed and commissioned around the world. Many of the major problems in the development and design of the optical components capable of handling the extremely high heat loads of the generated x-ray beams have been resolved. It is expected, however, that in the next few years even more powerful x-ray beams will be produced at these facilities, for example, by increasing the particle beam current. In this paper, the design of a next generation of synchrotron x-ray mirrors is discussed. The author shows that the design of contact-cooled mirrors capable of handing x-ray beam heat fluxes in excess of 500 W/mm{sup 2} - or more than three times the present level - is well within reach, and the limiting factor is the thermal stress rather then thermally induced slope error.

Khounsary, A.

1999-10-29

409

Applications of the genetic algorithm to the unit commitment problem in power generation industry  

Microsoft Academic Search

This paper proposes an innovative genetic algorithm (GA) approach to solve the thermal unit commitment (UC) problem in power generation industry through a constraint satisfaction technique. Due to a large variety of constraints to be satisfied, the solution space of the UC problem is highly nonconvex, and therefore the UC problem can not be solved efficiently by the standard GA.

Hong-Tzer Yang; Pai-Chuan Yang; Ching-Lien Huang

1995-01-01

410

Critical Contributions in MHD Power Generation. Quarterly Technical Progress Report, December 1, 1976--February 28, 1977.  

National Technical Information Service (NTIS)

Research progress in open-cycle coal-fired MHD power generation at Massachusetts Institute of Technology (MIT) is reported. The scope and objectives of the MIT program are to: (1) Establish chemical, thermal, and electrical data to guide materials selecti...

J. F. Louis

1977-01-01

411

Generation of Multitemporal Thermal Orthophotos from Uav Data  

NASA Astrophysics Data System (ADS)

The paper deals with using a TIR camera on an UAV for acquiring multitemporal thermal images of a building block against the background of detecting, monitoring and analysing urban heat islands. It is motivated by a research project called EO2HEAVEN (Earth Observation and Environmental Modelling for the Mitigation of Health Risks) which analyses the influence of environmental effects to human health. Therefore, the aim is the generation of thermal orthophotos from UAV data which can be used for further thematic analysis. The paper describes the data acquisition on the one hand and the processing of the obtained data on the other hand. The data acquisition comprises three image flights at different times of day from which only the first two missions could be processed until now. The low image contrasts, the radiometric differences between images as well as the poor initial positioning and orientation values limit the suitability of available software for automatic tie point measurement so that this step was outsourced and implemented in C++. The following aerial triangulation and orthophoto generation was realised in TerraPhoto (Terrasolid). However, two orthophotos could be generated with a geometric resolution of 15 cm. Furthermore, the radiation temperatures from the thermal images were compared to ground measurements to check the correctness of the camera measurements.

Pech, K.; Stelling, N.; Karrasch, P.; Maas, H.-G.

2013-08-01

412

A Vector Control for Grid-connected Wind Power Generation with Doubly Fed Induction Generator  

NASA Astrophysics Data System (ADS)

Recently, doubly fed induction generator (DFIG) and synchronous generator are mostly applied for wind power generation due to high efficiently for wind energy capture. An inverter system is required to control wind turbine speed and power factor in those generators. The inverter rating of the synchronous generator equals to generator rating. However, DFIG has the advantage that the inverter rating is about 25% to the generator rating. The paper describes a vector control of DFIG inter-connected to power line. The performance of proposed vector control is examined using power system simulation software PSCAD/EMTDC for the DFIG inter-connected to 6.6kv distribution line. The results show good dynamic responses and high accuracy to the stator active power control and the stator reactive power control.

Kai, Takaaki; Tanaka, Yuji; Kaneda, Hirotoshi; Kobayashi, Daichi; Tanaka, Akio

413

Load Frequency Control in Power System with Distributed Generation  

NASA Astrophysics Data System (ADS)

This paper proposes a method to improve the load frequency control in a power system with distributed generation (DG). DG is assumed to include photovoltaic generation, wind power generation, fuel cells and etc. In this paper, a simulation is performed using a microgrid model or island model that is composed of a storage system with either wind power generation or photovoltaic generation system as the DG. The effectiveness of load frequency control (LFC) using a storage system is examined using a power transmission simulator. The model for the experiment has been composed of inverter, battery, synchronous generator and load. Using this model, the comparison examination was done in respect of output setting control and the case in which the PI control was used. As a result, when the output set-point control using power demand estimation method is executed, the control characteristic is very excellent.

Yukita, Kazuto; Ota, Takuya; Fujimoto, Koji; Goto, Yasuyuki; Ichiyanagi, Katuhiro

414

Generation and detection of broadband laser generated ultrasound from low-power laser sources  

NASA Astrophysics Data System (ADS)

This paper presents the basic principles of the laser generation of ultrasound (LGU) through thermal conversion and illustrates the approaches to its use in material evaluation using the broadband features of the source. Traditional LGU involves high energy optical pulse irradiation which often induces surface damage, especially in carbon or glass fiber composites. We therefore expand the concept into low power excitations using laser diode sources. This enables excitation without damage but requires coded temporal signals. Arrays of semiconductor laser sources can also produce very broadband acoustic signals, both temporally and spatially. Piezoelectric sources are usually the opposite constrained in both space and time. This basic observation opens new avenues of material investigation, some of which feature in this paper.

Atherton, Kathryn; Culshaw, Brian; Dong, Fengzhong; Jun, Pan; Pierce, S. Gareth; Swift, Colin I.

2001-09-01

415

High-voltage pulse generations by power conditioning of flux compression generators  

Microsoft Academic Search

To power a high impedance load such as a microwave generator by using a flux compression generator (FCG), a power conditioning system (PCS) is needed. For this purpose, three types of power conditioning systems were designed; Types 1 to 3. The output of those systems were measured and compared. Type-1 was made up of a mousetrap-type explosive opening switch, an

Jeonghyeon Kuk; Dongwoo Yim; Jingi Kim; Cheonho Kim

2007-01-01

416

Power Maximization Control of Variable Speed Wind Generation System Using Permanent Magnet Synchronous Generator  

NASA Astrophysics Data System (ADS)

This paper proposes the sensorless output power maximization control of the wind generation system. A permanent magnet synchronous generator (PMSG) is used as a variable speed generator in the proposed system. The generator torque is suitably controlled according to the generator speed and thus the power from a wind turbine settles down on the maximum power point by the proposed MPPT control method, where the information of wind velocity is not required. Moreover, the maximum available generated power is obtained by the optimum current vector control. The current vector of PMSG is optimally controlled according to the generator speed and the required torque in order to minimize the losses of PMSG considering the voltage and current constraints. The proposed wind power generation system can be achieved without mechanical sensors such as a wind velocity detector and a position sensor. Several experimental results show the effectiveness of the proposed control method.

Morimoto, Shigeo; Nakamura, Tomohiko; Takeda, Yoji

417

New generation low power radiation survey instruments  

SciTech Connect

A number of new, ultra-low-powered radiation instruments have recently been developed at Los Alamos. Among these are two instruments which use a novel power source to eliminate costly batteries. The newly developed gamma detecting radiac, nicknamed the Firefly, and the alpha particle detecting instrument, called the Simple Cordless Alpha Monitor, both use recent advances in miniaturization and powersaving electronics to yield devices which are small, rugged, and very power-frugal. The two instruments consume so little power that the need for batteries to run them is eliminated. They are, instead, powered by a charged capacitor which will operate the instruments for an hour or more. Use of a capacitor as a power source eliminates many problems commonly associated with battery-operated instruments, such as having to open the case to change batteries, battery storage life, availability of batteries in the field, and some savings in weight. Both line power and mechanical sources are used to charge the storage capacitors which power the instruments.

Waechter, D.A.; Bjarke, G.O.; Trujillo, F.; Umbarger, C.J.; Wolf, M.A.

1984-02-01

418

Microfabrication of a tapered channel for isoelectric focusing with thermally generated pH gradient.  

PubMed

A simple microfabrication technique for the preparation of a tapered microchannel for thermally generated pH gradient isoelectric focusing (IEF) has been demonstrated. The tapered channel was cut into a plastic sheet (thickness was 120 microm), and the channel was closed by sandwiching the plastic sheet between two glass microscope slides. The length of the microchannel was 5 cm. The width of the separation channel was 0.4 mm at the narrow end and 4 mm at the wide end. The channel was coated with polyacrylamide to prevent electroosmotic flow (EOF) during focusing. Two electrolyte vials were mounted on top of each end of the channel with the wide end of the channel connected to the cathodic vial and the narrow to the anodic vial. The feasibility of the thermally generated pH gradient in a tapered channel was demonstrated. Important parameters that determined the feasibility of using a thermally generated pH gradient in a tapered channel were analyzed. Parameters to be optimized were control of EOF and hydrodynamic flow, selection of power supply mode and prevention of local overheating and air bubble formation. Tris-HCl buffer, which has a high pK(a) dependence with temperature, was used both to dissolve proteins and as the electrolyte. The thermally generated pH gradient separation of proteins was tested by focusing dog, cat and human hemoglobins with a whole column detection capillary IEF (CIEF) system. PMID:12412118

Huang, Tiemin; Pawliszyn, Janusz

2002-10-01

419

Future Photovoltaic Power Generation for Space-Based Power Utilities  

NASA Technical Reports Server (NTRS)

This paper discusses requirements for large earth orbiting power stations that can serve as central utilities for other orbiting spacecraft, or for beaming power to the earth itself. The current state of the art of space solar cells, and a variety of both evolving thin film cells as well as new technologies that may impact the future choice of space solar cells for high power mission applications are addressed.

Bailey, Sheila; Landis, Geoffrey; Hepp, Aloysius; Raffaelle, Ryne

2002-01-01

420

Buoyancy-Induced Columnar Vortices for Power Generation  

NASA Astrophysics Data System (ADS)

Large-scale inherent instability of a thermally stratified, solar-heated air layer is exploited for power generation by deliberately enhancing the formation of intense columnar vortices such that each vortex drives a vertical-axis turbine. In nature, buoyancy-driven vortices ("dust devils") occur spontaneously, with core diameters of 1-50 m at the surface, heights up to one kilometer, with induced air flow of considerable angular and linear momentum. Meter-scale laboratory experiments have demonstrated the nucleation and sustainment of strong buoyancy-driven vortices over a plane heated surface driven by a controllable power source. The present investigation focuses on the characterization of the columnar vortex and passive control of its core structure and strength for harvesting mechanical energy. It is shown that vortices having cores with nearly-uniform vorticity distributions can be "anchored" to small ground protrusions, and their circulation and angular momentum can be controlled by geometrical modifications of these surface protrusion and simple flow vanes.

Simpson, Mark W.; Glezer, Ari

2010-11-01

421

Improvement of financial efficiency and cost effectiveness in energy sector: A case study from Indian thermal power plant  

Microsoft Academic Search

Electricity is generated based on potential resources like coal, crude oil, water, wind, solar and nuclear energy. India depends largely on thermal power using coal as raw material despite the reality that indigenous stock of this raw material is depleting fast. At the same time coal based thermal stations are losing out financial viability gradually in terms of deteoriating efficiency,

S. Ghosh; S. C. Basu; P. P. Sengupta

2010-01-01

422

A modular 550 watt, 25 watts per cubic inch power supply for next generation aircraft  

SciTech Connect

This paper describes the development of the HVS-550 high performance power supply to be used on next generation aircraft. The HVS- 550 was designed and built utilizing state-of-the-art surface mount construction, low profile magnetics and aggressive thermal management techniques. This combination allowed the module height to be only 0.58 inch. This paper discusses the unique requirements of military systems which bound the power supply parameters.

Holley, O.M. (Texas Instruments, Defense Systems and Electronics Group, Dallas, TX (US)); Bieschke, B. (Texas Instruments, Defense Systems and Electronics Group, Plano, TX (US))

1990-09-01

423

Generating interest, generating power: commercializing photovoltaics in the utility sector  

Microsoft Academic Search

Conventional views of the innovation adoption process promote knowledge, and technical knowledge in particular, as a key precursor to generating interest among potential adopters. “The more you know, the better” serves as a generic rule of thumb. In commercializing photovoltaics (PVs) in the utility sector, this approach deserves serious questioning. This research provides a parallel study of utility adopters of

Abram W. Kaplan

1999-01-01

424

Performance Assessment of OTEC Power Systems and Thermal Power Plants. Final Report. Volume 1.  

National Technical Information Service (NTIS)

The focus of this report is on closed-cycle ocean thermal energy conversion (OTEC) power systems under research at Purdue University. The working operations of an OTEC power plant are briefly discussed. Methods of improving the performance of OTEC power s...

W. Leidenfrost P. E. Liley A. T. McDonald I. Mudawwar J. T. Pearson

1985-01-01

425

Biomass pyrolysis for power generation — a potential technology  

Microsoft Academic Search

A wide range of process and routes are available for power generation from biomass. PYROLYSIS is another emerging technology, wherein biomass is converted to liquids, gases and char — liquid fuels being the main target. Power generation using this technology is essentially the use of pyrolytic oils for the gas turbine integrated into a combined cycle. Using this process has

Anuradda Ganesh; Rangan Banerjee

2001-01-01

426

Repetitive pulsed power generators using an inductive energy storage system  

Microsoft Academic Search

Pulsed power generators using an inductive energy storage system are extremely compact and lightweight in comparison with those using a capacitive energy storage system. A reliable opening switch operated repetitively is necessary to realize an inductive pulsed power generator. Two kinds of repetitively operated opening switches have been developed in Kumamoto University. One is an exploding copper wire set by

H. Akiyama; U. Katschinski; K. Murayama; S. Katsuki; S. Tsukamoto

1995-01-01

427

Magnetic switching techniques for high power pulse generation  

Microsoft Academic Search

Since reliable generation of high power pulse with high efficiency makes a reintroduction of the magnetic switches desirable, experiments to demonstrate the possibility of using solid state switches (thyristors) in conjunction with magnetic pulse compression techniques in high power pulse generators were performed. Principles of magnetic switches and pulse transformers were considered and theoretical and experimental results are presented. Since

Aart Louis Keet

1992-01-01

428

Flux compression generators as plasma compression power sources  

Microsoft Academic Search

A survey is made of applications where explosive-driven magnetic flux compression generators are used to directly power devices that produce dense plasmas. Representative examples are discussed that are specific to the theta pinch, the plasma gun, the dense plasma focus, and the Z pinch in order to illustrate the high energy and power capabilities of explosive generators. An application employing

C. M. Fowler; R. S. Caird; D. J. Erickson; B. L. Freeman; W. B. Garn

1979-01-01

429

Optimal pricing of non-utility generated electric power  

Microsoft Academic Search

The importance of an optimal pricing policy for pricing nonutility generated power is pointed out in this paper. An optimal pricing policy leads to benefits for all concerned: the utility, industry, and the utility's other customers. In this paper, it is shown that reliability differentiated real-time pricing provides an optimal nonutility generated power pricing policy, from a societal welfare point

Shams N. Siddiqi; Martin L. Baughman

1994-01-01

430

Shorted stator induction generator for low wind speed power application  

Microsoft Academic Search

Shorted stator induction generator (IG) is presented for low wind speed power application. An analytical model is derived for predicting electrical performance of the generator while operating in regions 1 and 2 of turbine power versus wind speed curve. This paper determines an explicit optimal stator electrical speed of operation since the stator is disconnected from synchronism with the grid.

Adeola Balogun; Olorunfemi Ojo; Frank Okafor

2010-01-01

431

Green power - wind generated protection and control considerations  

Microsoft Academic Search

Wind-generated energy systems have some unique challenges for protection and control engineers. The typical wind farm is not a new form of generation being interconnected to the bulk power system. The success of the evolving Green Power Interconnected Projects is very dependent on the following of a logical method used by electrical systems, leading to a long life for the

D. Hornak; N. H. J. Chau

2004-01-01

432

Impact of Renewable Distributed Generation on Power Systems  

Microsoft Academic Search

The traditional approach in electric power generation is to have centralized plants distributing electricity through an extensive transmission & distribution network. Distributed generation (DG) provides electric power at a site closer to the customer, eliminating the unnecessary transmission and distribution costs. In addition, it can reduce fossil fuel emissions, defer capital cost, reduce maintenance investments and improve the distribution feeder

Miroslav Begovic; Aleksandar Pregelj; Ajeet Rohatgi; Damir Novosel

2001-01-01

433

POTENTIAL FOR SIGNIFICANT WIND POWER GENERATION AT ANTARCTIC STATIONS  

Microsoft Academic Search

The Antarctic scientific stations are generally powered by conventional diesel boilers and generator sets which consume large amounts of fossil fuels. In addition to being difficult and expensive to ship, fuel can threaten the local environment. The potential for wind power generation is high, but few commercial wind turbines can resist the harsh local conditions. The 10 kW \\

Antoine Guichard; Peter Magill; Patrice Godon; David Lyons; Chris Brown

434

Thermal-hydraulics for space power, propulsion, and thermal management system design  

SciTech Connect

The present volume discusses thermal-hydraulic aspects of current space projects, Space Station thermal management systems, the thermal design of the Space Station Free-Flying Platforms, the SP-100 Space Reactor Power System, advanced multi-MW space nuclear power concepts, chemical and electric propulsion systems, and such aspects of the Space Station two-phase thermal management system as its mechanical pumped loop and its capillary pumped loop's supporting technology. Also discussed are the startup thaw concept for the SP-100 Space Reactor Power System, calculational methods and experimental data for microgravity conditions, an isothermal gas-liquid flow at reduced gravity, low-gravity flow boiling, computations of Space Shuttle high pressure cryogenic turbopump ball bearing two-phase coolant flow, and reduced-gravity condensation.

Krotiuk, W.J.

1990-01-01

435

A General Model for the Electric Power and Energy Efficiency of a Solar Thermoelectric Generator  

Microsoft Academic Search

A general model for the electric power and energy efficiency of a solar thermoelectric generator is discussed, considering\\u000a the influences of the input energy, the thermal conductivity, the absorptivity and emissivity of the heat collector, and the\\u000a cooling water. The influences of these factors on the performance of the thermoelectric device are discussed, considering\\u000a the thermoelectric generator as a whole,

Yonghua Cai; Jinsheng Xiao; Wenyu Zhao; Xinfeng Tang; Qingjie Zhang

2011-01-01

436

Vibration characteristics about thermal variation of BFP in power plant  

NASA Astrophysics Data System (ADS)

BFPs(Boiler Feedwater Pump) in power plants are used for pumping high pressure and high temperature water. The pressure pulsation of high pressure pumps is the vibration caused by fluid forces. If the frequency of the exciting source is adjacent to one of the natural frequencies of the pump, it can cause high vibration by resonance. The natural vibration characteristics of pump depend on thermal variation. This paper examines vibration characteristics due to thermal variation experimentally and analytically.

Song, A. H.; Song, J. D.; Kim, H. S.; Jung, G. C.

2012-11-01

437

A review of power battery thermal energy management  

Microsoft Academic Search

This paper reviews the development of clean vehicles, including pure electric vehicles (EVs), hybrid electric vehicles (HEVs) and fuel cell electric vehicles (FCEVs), and high energy power batteries, such as nickel metal hydride (Ni-MH), lithium-ion (Li-ion) and proton exchange membrane fuel cells (PEMFCs). The mathematical models and thermal behavior of the batteries are described. Details of various thermal management techniques,

Zhonghao Rao; Shuangfeng Wang

2011-01-01

438

Microwave power generation by magnetic superlattices  

NASA Astrophysics Data System (ADS)

We report on microwave power emission by ballistic electrons as they cross a region of spatially inhomogeneous magnetic field. Magnetic finger gates were fabricated at the surface of high mobility GaAs/AlGaAs Hall bars embedded in a coplanar waveguide. By modulating the current injected through the Hall bar and measuring the second harmonic of the signal rectified by a Schottky detector, we obtain the microwave power emitted by the superlattice. This power (~6 W m-2) is compared to the fluorescence of electron spins that undergo spin resonance as they cross domains of opposite magnetic field.

Littlejohn, S.; Nogaret, A.; Davies, S. R.; Henini, M.; Beere, H. E.; Ritchie, D. A.

2011-12-01

439

Power generation from conductive droplet sliding on electret film  

NASA Astrophysics Data System (ADS)

Generating electrical power from low frequency vibration to power portable devices is a challenge that potentially can be met by nonresonant electrostatic energy harvesters. We propose a generator employing a conductive droplet sliding on a microfabricated electret film which is sputtered onto an interdigital electrode and charged already during deposition. Droplet motion causes a capacitance variation that is used to generate electric power. A prototype of the fluidic energy harvester demonstrated a peak output power at 0.18 µW with a single droplet having a diameter of 1.2 mm and sliding on a 2 -µm thick electret film.

Yang, Zhaochu; Halvorsen, Einar; Dong, Tao

2012-05-01

440

Analysis of a combined refrigerator-generator space power system  

NASA Technical Reports Server (NTRS)

Compatibility of the Brayton power and refrigeration cycles is considered. Performance of the power- and cryo-loop is plotted against compressor pressure ratio. The power- and cryo-loop performance is determined by dividing the compressor work between the two loops in proportion to mass flow rate. Cycle efficiency is defined as the ratio of shaft power available in the power loop to the net thermal input from the heat source. The available shaft power is the excess of the power turbine work over the compressor work needed in the power loop. The best power loop efficiency occurred at a compressor pressure ratio of 1.8, and the best cryo-loop performance was at a compressor pressure ratio of 2.1. Good individual cycle performance occurred over a fairly large range in compressor pressure ratio.

Klann, J. L.

1973-01-01

441

HIGH EFFICIENCY GENERATION OF HYDROGEN FUELS USING NUCLEAR POWER  

SciTech Connect

OAK B202 HIGH EFFICIENCY GENERATION OF HYDROGEN FUELS USING NUCLEAR POWER. Combustion of fossil fuels, used to power transportation, generate electricity, heat homes and fuel industry provides 86% of the world's energy. Drawbacks to fossil fuel utilization include limited supply, pollution, and carbon dioxide emissions. Carbon dioxide emissions, thought to be responsible for global warming, are now the subject of international treaties. Together, these drawbacks argue for the replacement of fossil fuels with a less-polluting potentially renewable primary energy such as nuclear energy. Conventional nuclear plants readily generate electric power but fossil fuels are firmly entrenched in the transportation sector. Hydrogen is an environmentally attractive transportation fuel that has the potential to displace fossil fuels. Hydrogen will be particularly advantageous when coupled with fuel cells. Fuel cells have higher efficiency than conventional battery/internal combustion engine combinations and do not produce nitrogen oxides during low-temperature operation. Contemporary hydrogen production is primarily based on fossil fuels and most specifically on natural gas. When hydrogen is produced using energy derived from fossil fuels, there is little or no environmental advantage. There is currently no large scale, cost-effective, environmentally attractive hydrogen production process available for commercialization, nor has such a process been identified. The objective of this work is to find an economically feasible process for the production of hydrogen, by nuclear means, using an advanced high-temperature nuclear reactor as the primary energy source. Hydrogen production by thermochemical water-splitting (Appendix A), a chemical process that accomplishes the decomposition of water into hydrogen and oxygen using only heat or, in the case of a hybrid thermochemical process, by a combination of heat and electrolysis, could meet these goals. Hydrogen produced from fossil fuels has trace contaminants (primarily carbon monoxide) that are detrimental to precious metal catalyzed fuel cells, as is now recognized by many of the world's largest automobile companies. Thermochemical hydrogen will not contain carbon monoxide as an impurity at any level. Electrolysis, the alternative process for producing hydrogen using nuclear energy, suffers from thermodynamic inefficiencies in both the production of electricity and in electrolytic parts of the process. The efficiency of electrolysis (electricity to hydrogen) is currently about 80%. Electric power generation efficiency would have to exceed 65% (thermal to electrical) for the combined efficiency to exceed the 52% (thermal to hydrogen) calculated for one thermochemical cycle. Thermochemical water-splitting cycles have been studied, at various levels of effort, for the past 35 years. They were extensively studied in the late 70s and early 80s but have received little attention in the past 10 years, particularly in the U.S. While there is no question about the technical feasibility and the potential for high efficiency, cycles with proven low cost and high efficiency have yet to be developed commercially. Over 100 cycles have been proposed, but substantial research has been executed on only a few. This report describes work accomplished during a three-year project whose objective is to ''define an economically feasible concept for production of hydrogen, by nuclear means, using an advanced high temperature nuclear reactor as the energy source.'' The emphasis of the first phase was to evaluate thermochemical processes which offer the potential for efficient, cost-effective, large-scale production of hydrogen from water in which the primary energy input is high temperature heat from an advanced nuclear reactor and to select one (or, at most three) for further detailed consideration. During Phase 1, an exhaustive literature search was performed to locate all cycles previously proposed. The cycles located were screened using objective criteria to determine which could benefit, in terms of efficien

BROWN,LC; BESENBRUCH,GE; LENTSCH,RD; SCHULTZ,KR; FUNK,JF; PICKARD,PS; MARSHALL,AC; SHOWALTER,SK

2003-06-01

442

Coal gasification for electric power generation.  

PubMed

The electric utility industry is being severely affected by rapidly escalating gas and oil prices, restrictive environmental and licensing regulations, and an extremely tight money market. Integrated coal gasification combined cycle (IGCC) power plants have the potential to be economically competitive with present commercial coal-fired power plants while satisfying stringent emission control requirements. The current status of gasification technology is discussed and the critical importance of the 100-megawatt Cool Water IGCC demonstration program is emphasized. PMID:17788466

Spencer, D F; Gluckman, M J; Alpert, S B

1982-03-26

443

Variable-Speed Engine Generator With Supercapacitor: Isolated Power Generation System and Fuel Efficiency  

Microsoft Academic Search

A variable-speed engine generator set for an isolated power system is investigated due to reduced fuel consumption and less emission. However, because of the sluggish dynamic behavior of the internal combustion engine, the power quality would be degraded during the sudden load power surge, where the power required by the load is not available by the engine because of the

Joon-Hwan Lee; Seung-Hwan Lee; Seung-Ki Sul

2009-01-01

444

Simulation of a seawater MHD power generation system  

NASA Astrophysics Data System (ADS)

MHD (magnetohydrodynamics) power generation systems are expected to become popular with the development of superconducting technology because of their low cost and high efficiency. MHD power generation directly utilizes electromotive force, which arises when seawater crosses a magnetic field. The helical-type MHD generator is composed mainly of a helical partition board and electrodes, which include a cathode pipe on the exterior of the generator and an anode rod in the interior. Elementary research on a helical-type MHD power generation system has started at Kobe University, and a numerical simulation of the system has been carried out by FEM (Finite Element Method) at the National Institute for Materials Science. By comparing the simulation results with the theoretical and experimental results, we found that the proposed method is valid for simulating the MHD power generation system.

Liu, Xiaojun; Kiyoshi, Tsukasa; Takeda, Minoru

2006-05-01

445

A global fouling factor methodology for analyzing steam generator thermal performance degradation  

SciTech Connect

Over the past few years, steam generator (SG) thermal performance degradation has led to decreased plant efficiency and power output at numerous PWR nuclear power plants with recirculating-type SGs. The authors have developed and implemented methodologies for quantitatively evaluating the various sources of SG performance degradation, both internal and external to the SG pressure boundary. These methodologies include computation of the global fouling factor history, evaluation of secondary deposit thermal resistance using deposit characterization data, and consideration of pressure loss causes unrelated to the tube bundle, such as hot-leg temperature streaming and SG moisture separator fouling. In order to evaluate the utility of the global fouling factor methodology, the authors performed case studies for a number of PWR SG designs. Key results from two of these studies are presented here. In tandem with the fouling-factor analyses, a study evaluated for each plant the potential causes of pressure loss. The combined results of the global fouling factor calculations and the pressure-loss evaluations demonstrated two key points: (1) that the available thermal margin against fouling, which can vary substantially from plant to plant, has an important bearing on whether a given plant exhibits losses in electrical generating capacity, and (2) that a wide variety of causes can result in SG thermal performance degradation.

Kreider, M.A.; White, G.A.; Varrin, R.D. Jr. [Dominion Engineering, Inc., McLean, VA (United States)

1998-06-01

446

Operation and efficiency of large-scale solar thermal power plants  

NASA Astrophysics Data System (ADS)

Nine large solar thermal power plants, 15 - 80 MWe in scale, located in Southern California's Mojave Desert, are proving since 1985 that power solar technology is a working reality. These plants produce over 90% of solar electric generation in the world. This paper provides summary information, more particularly on five of the SEGS (Solar Electric Generating Systems) plants located at Kramer Junction, and operated by KJC Operating Company. General description of the plants and the technologies involved are discussed with an overview of performance after five years of full operation.

Cohen, Gilbert E.

1993-10-01

447

Fuel procurement for first generation fusion power plants  

Microsoft Academic Search

The provision of deuterium, tritium, lithium and beryllium fuel materials for fusion power plants is examined in this document. Possible fusion reactions are discussed for use in first generation power plants. Requirements for fuel materials are considered. A range of expected annual consumption is given for each of the materials for a 1000 megawatts electric (MWe) fusion power plant. Inventory

B. F. Gore; P. L. Hendrickson

1976-01-01

448

A new controller for efficient wave power generation  

Microsoft Academic Search

Based on the stator current control of induction machine, a new current control scheme is developed for making the peak power to average power ratio of the wave power feeding in to the mains around unity. The proposed scheme is realised using an AC voltage controller. The induction machine operates both in motor and generating modes. Both simulation and test

ALLABAKSH L. NAIKODI; G. Sridhara Rao

1995-01-01

449

Micromachined CMOS thermoelectric generators as on-chip power supply  

Microsoft Academic Search

As the power consumption of a large number of microelectronic devices has been continuously reduced in recent years, power supply units of a few microwatts have become sufficient for their operation. Our improved micro-scale thermoelectric generator (?-TEG) is based on polysilicon surface micromachining and is designed to convert waste heat into electrical power. Since this device is compatible with standard

M. Strasser; R. Aigner; C. Lauterbach; T. F. Sturm; M. Franosh; G. Wachutka

2003-01-01

450

Using neural networks to estimate wind turbine power generation  

Microsoft Academic Search

This paper uses data collected at Central and South West Services Fort Davis wind farm (USA) to develop a neural network based prediction of power produced by each turbine. The power generated by electric wind turbines changes rapidly because of the continuous fluctuation of wind speed and direction. It is important for the power industry to have the capability to

Shuhui Li; Donald C. Wunsch; Edgar A. O'Hair; Michael G. Giesselmann

2001-01-01

451

Optimal operation of distribution power system including distributed generator  

Microsoft Academic Search

A new model for distribution system reconfiguration (DSR) integrated with optimal power flow (OPF) and optimal capacitor switching (OCS) based on a hybrid approach is proposed in this paper. The objective is to minimize the generation cost of the whole distribution power system, and is subject to constraints such as capacity limit of branches, minimum and maximum power limits of

J. Shu; S. S. Quan; L. Z. Zhang

2010-01-01

452

Primary electric power generation systems for advanced-technology engines  

NASA Technical Reports Server (NTRS)

The advantages of the all electric airplane are discussed. In the all electric airplane the generator is the sole source of electric power; it powers the primary and secondary flight controls, the environmentals, and the landing gear. Five candidates for all electric power systems are discussed and compared. Cost benefits of the all electric airplane are discussed.

Cronin, M. J.

1983-01-01

453

Optical fiber instrumentation of a high power generator and turbine  

NASA Astrophysics Data System (ADS)

The instrumentation of a high power generator and its complementary systems including the turbine bearings is presented and discussed. The generator consists of a 175MW hydroelectric generator installed in the Salto Osório power plant in the southern region of Brazil. Results show good agreement with the already existing instrumentation and demonstrate the technology potential for a full optical fiber sensing system to monitor these large machines.

da Silva, Erlon Vagner; Dreyer, Uilian José; de Morais Sousa, Kleiton; Babinski, Valderi Junot; Somenzi, Jonas; Mezzadri, Felipe; de Lourenço Junior, Ivo; Martelli, Cicero; Cardozo da Silva, Jean Carlos

2013-05-01

454

A permanent-magnet generator for wind power applications  

Microsoft Academic Search

In order to achieve the gearless construction of a wind energy conversion system (WECS), a low-speed (i.e. multipole) generator is required. This paper examines an axial-field permanent-magnet synchronous wind power generator, mainly from the magnetic viewpoint. Both mechanical and electromagnetic designs are described as well as some primary test results concerning model generators having nominal power of 5 and 10

L. Soederlund; J.-T. Eriksson; J. Salonen; H. Vihriaelae; R. Peraelae

1996-01-01

455

Introduction of Car Alternators for Small Scale Wind Power Generation  

Microsoft Academic Search

Generally Permanent Magnet Generators (PMGs) are widely used for small-scale wind power generation. But in Sri Lanka, it is difficult to find a competitive market for such generators and permanent magnets, since the price of a PMG is very high and is very rare.Due to such conditions, expansion of small-scale wind power applications among rural communities are significantly limited. The

Nanayakkara D. P. N

456

Terrestrial Solar Thermal Power Plants: On the Verge of Commercialization  

NASA Astrophysics Data System (ADS)

Solar Thermal Power Plants (STPP) with optical concentration technologies are important candidates for providing the bulk solar electricity needed within the next few decades, even though they still suffer from lack of dissemination and confidence among citizens, scientists and decision makers. Concentrating solar power is represented nowadays at pilot-scale and demonstration-scale by four technologies, parabolic troughs, linear Fresnel reflector systems, power towers or central receiver systems, and dish/engine systems, which are ready to start up in early commercial/demonstration plants. Even though, at present those technologies are still three times more expensive than intermediate-load fossil thermal power plants, in ten years from now, STPP may already have reduced production costs to ranges competitive. An important portion of this reduction (up to 42%) will be obtained by R&D and technology advances in materials and components, efficient integration schemes with thermodynamic cycles, highly automated control and low-cost heat storage systems.

Romero, M.; Martinez, D.; Zarza, E.

2004-12-01

457

On low-frequency electric power generation with PZT ceramics  

Microsoft Academic Search

Piezoelectric materials have long been used as sensors and actuators, however their use as electrical generators is less established. A piezoelectric power generator has great potential for some remote applications such as in vivo sensors, embedded MEMS devices, and distributed networking. Such materials are capable of converting mechanical energy into electrical energy, but developing piezoelectric generators is challenging because of

Stephen R. Platt; Shane Farritor; Hani Haider

2005-01-01

458

The status of world geothermal power generation 1995–2000  

Microsoft Academic Search

In order to assess the current status of international geothermal power generation, the author has reviewed the Country Update (CU) papers submitted to the World Geothermal Conference 2000 in Japan from nations generating or planning to generate electricity. Salient facts in these papers have been synthesized and summary descriptions of geothermally-related activities written. Finally, following a brief discussion, conclusions are

Gerald W. Huttrer

2001-01-01

459

Optimal load shedding strategy in power systems with distributed generation  

Microsoft Academic Search

An optimal load shedding strategy for power systems with multiple distributed generation is presented. According to distributed generation's role in emergency state, they are classified as the central generation type, nondispatchable type and storage type. The dynamic and static models of each type following a major disturbance are developed. Based on the analysis of a major disturbance in a grid

Ding Xu; Adly A. Girgis

2001-01-01

460

4. 5MW fuel cell tackles Tokyo's power generation problems  

Microsoft Academic Search

Dispersed phosphoric acid fuel cell generators may be one of the answers to Tokyo's power-generation problem. Fuel cells combine fuel and oxygen, without combustion, to produce electricity. Because of their size - 10 to 50 MW - generators can be sited within the city, close to the load demand. The fuel cell's low emissions, high efficiency, rapid deployment, and low

D. M. Rastler; M. Kobayashi; L. M. Handley

1987-01-01

461

Regulation Properties of a System MHD Generator - Electric Power Network.  

National Technical Information Service (NTIS)

In this report several problems connected with the mutual operation of MHD generator and electric power network are described, i.e. regulation properties of the MHD-generator, optimal matching of the MHD-generator and converters, current regulation in tra...

Krzysztof D

1987-01-01

462

Efficiency at maximum power of thermally coupled heat engines.  

PubMed

We study the efficiency at maximum power of two coupled heat engines, using thermoelectric generators (TEGs) as engines. Assuming that the heat and electric charge fluxes in the TEGs are strongly coupled, we simulate numerically the dependence of the behavior of the global system on the electrical load resistance of each generator in order to obtain the working condition that permits maximization of the output power. It turns out that this condition is not unique. We derive a simple analytic expression giving the relation between the electrical load resistance of each generator permitting output power maximization. We then focus on the efficiency at maximum power (EMP) of the whole system to demonstrate that the Curzon-Ahlborn efficiency may not always be recovered: The EMP varies with the specific working conditions of each generator but remains in the range predicted by irreversible thermodynamics theory. We discuss our results in light of nonideal Carnot engine behavior. PMID:22680454

Apertet, Y; Ouerdane, H; Goupil, C; Lecoeur, Ph

2012-04-01

463

Lifetime prediction modeling of airfoils for advanced power generation  

NASA Astrophysics Data System (ADS)

The use of gases produced from coal as a turbine fuel offers an attractive means for efficiently generating electric power from our Nation's most abundant fossil fuel resource. The oxy-fuel and hydrogen-fired turbine concepts promise increased efficiency and low emissions on the expense of increased turbine inlet temperature (TIT) and different working fluid. Developing the turbine technology and materials is critical to the creation of these near-zero emission power generation technologies. A computational methodology, based on three-dimensional finite element analysis (FEA) and damage mechanics is presented for predicting the evolution of creep and fatigue in airfoils. We took a first look at airfoil thermal distributions in these advanced turbine systems based on CFD analysis. The damage mechanics-based creep and fatigue models were implemented as user modified routine in commercial package ANSYS. This routine was used to visualize the creep and fatigue damage evolution over airfoils for hydrogen-fired and oxy-fuel turbines concepts, and regions most susceptible to failure were indentified. Model allows for interaction between creep and fatigue damage thus damage due to fatigue and creep processes acting separately in one cycle will affect both the fatigue and creep damage rates in the next cycle. Simulation results were presented for various thermal conductivity of the top coat. Surface maps were created on the airfoil showing the development of the TGO scale and the Al depletion of the bond coat. In conjunction with model development, laboratory-scale experimental validation was executed to evaluate the influence of operational compressive stress levels on the performance of the TBC system. TBC coated single crystal coupons were exposed isothermally in air at 900, 1000, 1100oC with and without compressive load. Exposed samples were cross-sectioned and evaluated with scanning electron microscope (SEM). Performance data was collected based on image analysis. Energy-dispersive x-ray (EDX) was employed to study the elemental distribution in TBC system after exposure. Nanoindentation was used to study the mechanical properties (Young's modulus and hardness) of the components in the TBC system and their evolution with temperature and time.

Karaivanov, Ventzislav Gueorguiev

464

Two dimensional thermal and charge mapping of power thyristors  

NASA Technical Reports Server (NTRS)

The two dimensional static and dynamic current density distributions within the junction of semiconductor power switching devices and in particular the thyristors were obtained. A method for mapping the thermal profile of the device junctions with fine resolution using an infrared beam and measuring the attenuation through the device as a function of temperature were developed. The results obtained are useful in the design and quality control of high power semiconductor switching devices.

Hu, S. P.; Rabinovici, B. M.

1975-01-01

465

Powering a Generation of Change: A Smithsonian Documentation Project  

NSDL National Science Digital Library

Powering a Generation of Change is a Smithsonian Institution documentation project that is a response to the coming deregulation of the electric power industry in the United States and Canada. The site is interesting almost as much for its information on electricity and the history of electric power regulation, as for its information explaining deregulation and its societal impacts. One of the highlights of the site is the Visions of Power section, with in-depth interviews with Joseph P. Kearney of US Generating, Andre Caille of Hydro-Quebec, and William T. McCormick, Jr. of CMS Energy. Visions of Power offers numerous links to information provided by a variety of participants in the deregulation debate. The Powering the Past section provides a fascinating tour through the history of electric power, accompanied by images from various Smithsonian museums. A large bibliography on electric power is also available.

1997-01-01

466

Technical and economical system comparison of photovoltaic and concentrating solar thermal power systems depending on annual global irradiation  

Microsoft Academic Search

Concentrating solar thermal power and photovoltaics are two major technologies for converting sunlight to electricity. Variations of the annual solar irradiation depending on the site influence their annual efficiency, specific output and electricity generation cost. Detailed technical and economical analyses performed with computer simulations point out differences of solar thermal parabolic trough power plants, non-tracked and two-axis-tracked PV systems. Therefore,

Volker Quaschning

2004-01-01

467

Electricity generation and transmission planning in deregulated power markets  

NASA Astrophysics Data System (ADS)

This dissertation addresses the long-term planning of power generation and transmission facilities in a deregulated power market. Three models with increasing complexities are developed, primarily for investment decisions in generation and transmission capacity. The models are presented in a two-stage decision context where generation and transmission capacity expansion decisions are made in the first stage, while power generation and transmission service fees are decided in the second stage. Uncertainties that exist in the second stage affect the capacity expansion decisions in the first stage. The first model assumes that the electric power market is not constrained by transmission capacity limit. The second model, which includes transmission constraints, considers the interactions between generation firms and the transmission network operator. The third model assumes that the generation and transmission sectors make capacity investment decisions separately. These models result in Nash-Cournot equilibrium among the unregulated generation firms, while the regulated transmission network operator supports the competition among generation firms. Several issues in the deregulated electric power market can be studied with these models such as market powers of generation firms and transmission network operator, uncertainties of the future market, and interactions between the generation and transmission sectors. Results deduced from the developed models include (a) regulated transmission network operator will not reserve transmission capacity to gain extra profits; instead, it will make capacity expansion decisions to support the competition in the generation sector; (b) generation firms will provide more power supplies when there is more demand; (c) in the presence of future uncertainties, the generation firms will add more generation capacity if the demand in the future power market is expected to be higher; and (d) the transmission capacity invested by the transmission network operator depends on the characteristic of the power market and the topology of the transmission network. Also, the second model, which considers interactions between generation and transmission sectors, yields higher social welfare in the electric power market, than the third model where generation firms and transmission network operator make investment decisions separately.

He, Yang