Phase change thermal energy storage methods for combat vehicles, phase 1

Science.gov (United States)

Lynch, F. E.

1986-06-01

Three alternative cooling methods, based on latent heat absorption during phase changes, were studied for potential use in combat vehicle microclimate temperature control. Metal hydrides absorb heat as they release hydrogen gas. Plastic crystals change from one solid phase to another, absorbing heat in the process. Liquid air boils at cryogenic temperature and absorbs additional sensible heat as the cold gas mixes with the microclimate air flow. System designs were prepared for each of the three microclimate cooling concepts. These designs provide details about the three phase change materials, their containers and the auxiliary equipment needed to implement each option onboard a combat vehicle. The three concepts were compared on the basis of system mass, system volume and the energy required to regenerate them after use. Metal hydrides were found to be the lightest and smallest option by a large margin. The energy needed to regenerate a hydride thermal storage system can be extracted from the vehicle's exhaust gases.

Increasing energy efficiency of HVAC systems of buildings using phase change material

Energy Technology Data Exchange (ETDEWEB)

Chusak, Lee; Daiber, Jared; Agarwal, Ramesh [Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, MO 63130 (United States)

2012-07-01

Using Computational Fluid Dynamics (CFD), four different cooling systems used in contemporary office environments are modeled to compare energy consumption and thermal comfort levels. Incorporating convection and radiation technologies, full-scale models of an office room compare energy efficiency of (a) an all-air overhead system, (b) a combined all-air overhead and hydronic radiant system (chilled ceiling), (c) an all-air raised floor system (displacement ventilation), and (d) a combined displacement ventilation with a chilled ceiling. The computational domain for each model consists of one temperature varying wall (simulating the temperature of the exterior wall of the building during a 24-hour period) and adiabatic conditions for the remaining walls, floor, and ceiling (simulating interior walls of the room). Two sets of computations are conducted. The first set considers a glass window and plastic shade configuration for the exterior wall. The second set of computations includes a phase change material layer between the glass window and the plastic shade. Results show substantial energy savings can be accrued using the displacement ventilation and especially the displacement ventilation with a chilled ceiling over the conventional overhead mixing ventilation system. The results also show that the addition of a PCM layer to the exterior wall can significantly decrease the cooling energy requirements.

Phase relations and gibbs energies in the system Mn-Rh-O

Science.gov (United States)

Jacob, K. T.; Sriram, M. V.

1994-07-01

Phase relations in the system Mn-Rh-O are established at 1273 K by equilibrating different compositions either in evacuated quartz ampules or in pure oxygen at a pressure of 1.01 × 105 Pa. The quenched samples are examined by optical microscopy, X-ray diffraction, and energy-dispersive X-ray analysis (EDAX). The alloys and intermetallics in the binary Mn-Rh system are found to be in equilibrium with MnO. There is only one ternary compound, MnRh2O4, with normal spinel structure in the system. The compound Mn3O4 has a tetragonal structure at 1273 K. A solid solution is formed between MnRh2O4 and Mn3O4. The solid solution has the cubic structure over a large range of composition and coexists with metallic rhodium. The partial pressure of oxygen corresponding to this two-phase equilibrium is measured as a function of the composition of the spinel solid solution and temperature. A new solid-state cell, with three separate electrode compartments, is designed to measure accurately the chemical potential of oxygen in the two-phase mixture, Rh + Mn3-2xRh2xO4, which has 1 degree of freedom at constant temperature. From the electromotive force (emf), thermodynamic mixing properties of the Mn3O4-MnRh2O4 solid solution and Gibbs energy of formation of MnRh2O4 are deduced. The activities exhibit negative deviations from Raoult’s law for most of the composition range, except near Mn3O4, where a two-phase region exists. In the cubic phase, the entropy of mixing of the two Rh3+ and Mn3+ ions on the octahedral site of the spinel is ideal, and the enthalpy of mixing is positive and symmetric with respect to composition. For the formation of the spinel (sp) from component oxides with rock salt (rs) and orthorhombic (orth) structures according to the reaction, MnO (rs) + Rh2O3 (orth) → MnRh2O4 (sp), ΔG° = -49,680 + 1.56T (±500) J mol-1 The oxygen potentials corresponding to MnO + Mn3O4 and Rh + Rh2O3 equilibria are also obtained from potentiometric measurements on galvanic

Exergy analysis of an adiabatic compressed air energy storage system using a cascade of phase change materials

International Nuclear Information System (INIS)

Tessier, Michael J.; Floros, Michael C.; Bouzidi, Laziz; Narine, Suresh S.

2016-01-01

Adiabatic compressed air energy storage is an emerging energy storage technology with excellent power and storage capacities. Currently, efficiencies are approximately 70%, in part due to the issue of heat loss during the compression stage. An exergy analysis is presented on a novel adiabatic compressed air energy storage system design utilizing a cascade of PCMs (phase change materials) for waste heat storage and recovery. The melting temperatures and enthalpies of the PCMs were optimized for this system and were shown to be dependent on the number of PCMs, the number of compression stages, and the maximum compression ratio. Efficiencies of storage and recovery using this approach are predicted to be as high as 85%, a 15% increase over current designs which do not incorporate PCMs. - Highlights: • A compressed air energy storage plant using phase change materials is proposed. • Increasing number of phase change materials increases roundtrip exergy efficiency. • A thermodynamic model allows melting points and latent heats required to be predicted.

EcoGrid.dk Phase I. Steps towards a Danish power system with 50 % wind energy. Summary report

Energy Technology Data Exchange (ETDEWEB)

Noerregaard, K. (Teknologisk Institut, AArhus (Denmark)); OEstergaard, J.; Lind, M. (Technical Univ. of Denmark (DTU), CET, Kgs. Lyngby (Denmark)); Bach, P.-F. (Fredericia (Denmark)); Soerensen, P. (Technical Univ. of Denmark, Risoe National Lab. for Sustainable Energy, Roskilde (Denmark)); Tennbakk, B. (Econ Poeyry AS, Copenhagen (Denmark)); Togeby, M. (EA Energy Analyses a/s, Copenhagen (Denmark)); Ackermann, T. (Energynautics GmbH (Denmark))

2009-07-01

In the EcoGrid project phase I a unique combination of scientists, experts and industry stakeholders with different backgrounds and experiences were put together to work towards one common objective: Develop new long-term technologies for the power grid and system that can contribute to realizing the Danish Energy Policy goal of 50% wind energy by 2025. The specific task of the EcoGrid phase I report was to make a general description and analyses of demand and development of the Danish power system with increased volumes of renewable energy. The report describes different solutions with respect to new power system architecture; examine the consequences of future market developments and identify new measures ('building blocks') to support the overall goals and functions of the future power system. The main report includes five work-packages.

RF Phase Scan for Beam Energy Measurement of KOMAC DTL

Energy Technology Data Exchange (ETDEWEB)

Kim, Hansung; Kwon, Hyeokjung; Kim, Seonggu; Lee, Seokgeun; Cho, Yongsub [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2016-10-15

The energy gain through the drift tube linac is a function of the synchronous phase, therefore, the output beam energy from DTL can be affected by the RF phase setting in low-level RF (LLRF) system. The DTL at Korea Multi-purpose Accelerator Complex (KOMAC) consists of 11 tanks and the RF phase setting in each tank should be matched for synchronous acceleration in successive tanks. That means a proper setting of RF phase in each DTL tank is critical for efficient and loss-free operation. The matching RF phase can be determined based on the output energy measurement from the DTL tank. The beam energy can be measured by several methods. For example, we can use a bending magnet to determine the beam energy because the higher momentum of beam means the less deflection angle in the fixed magnetic field. By measuring the range of proton beam through a material with known stopping power also can be utilized to determine the beam energy. We used a well-known time-of-flight method to determine the output beam energy from the DTL tank by measuring beam phase with a beam position monitor (BPM). Based on the energy measurement results, proper RF operating point could be obtained. We performed a RF phase scan to determine the output beam energy from KOMAC DTL by using a time-of-flight method and to set RF operating point precisely. The measured beam energy was compared with a beam dynamics simulation and showed a good agreement. RF phase setting is critical issue for the efficient operation of the proton accelerator, we have a plan to implement and integrate the RF phase measurement system into an accelerator control system for future need.

Research for the energy turnaround. Phase transitions actively shape. Contributions

International Nuclear Information System (INIS)

Szczepanski, Petra; Wunschick, Franziska; Martin, Niklas

2015-01-01

The Annual Conference 2014 of the Renewable Energy Research Association was held in Berlin on 6 and 7 November 2014. This book documents the contributions of the conference on research for the energy turnaround, phase transitions actively shape. After an introduction and two contributions to the political framework, the contributions to the economic phases of the energy transition, the phase of the current turn, the phases of social energy revolution, the stages of heat turnaround (Waermewende), and the stages of the mobility turn deal with the stages of development of the energy system. Finally, the Research Association Renewable Energy is briefly presented. [de

Discharging process of a finned heat pipe–assisted thermal energy storage system with high temperature phase change material

International Nuclear Information System (INIS)

Tiari, Saeed; Qiu, Songgang; Mahdavi, Mahboobe

2016-01-01

Highlights: • The discharging process of a latent heat thermal energy storage system is studied. • The thermal energy storage system is assisted by finned heat pipes. • The influences of heat pipe spacing and fins geometrical features are studied. • Smaller heat pipe spacing enhances the solidification rate. • Better heat pipe and fin arrangements are determined. - Abstract: This paper presents the results of a numerical study conducted to investigate the discharging process of a latent heat thermal energy storage system assisted by finned heat pipes. A two-dimensional finite volume based numerical model along with enthalpy-porosity technique is employed to simulate the phase change of storage media during the discharging mode. The thermal energy storage system in this study consists of a square container, finned heat pipes, and potassium nitrate (KNO 3 ) as the phase change material. The charging process of the same thermal energy storage system was reported in an early paper by the authors. This paper reports the results of discharging process of the thermal energy storage system. The influences of heat pipe spacing, fin geometry and quantities as well as the effects of natural convection heat transfer on the thermal performance of the storage system were studied. The results indicate that the phase change material solidification process is hardly affected by the natural convection. Decreasing the heat pipe spacing results in faster discharging process and higher container base wall temperature. Increasing the fins length does not change the discharging time but yields higher base wall temperature. Using more fins also accelerates the discharging process and increases the container base wall temperature.

Phase Change Energy Storage Material Suitable for Solar Heating System

Science.gov (United States)

Li, Xiaohui; Li, Haihua; Zhang, Lihui; Liu, Zhenfa

2018-01-01

Differential scanning calorimetry (DSC) was used to investigate the thermal properties of palmitic acid, myristic acid, laurel acid and the binary composite of palmitic/laurel acid and palmitic/myristic acid. The results showed that the phase transition temperatures of the three monomers were between 46.9-65.9°C, and the latent heats were above 190 J/g, which could be used as solar energy storage material. When the mass ratio of Palmitic acid and myristic was 1:1, the eutectic mixture could be formed. The latent heat of the eutectic mixture was 186.6 J/g, the melting temperature and the solidification temperature was 50.6°C and 43.8°C respectively. The latent heat of phase change and the melting temperature had not obvious variations after 400 thermal cycles, which proved that the binary composite had good thermal stability and was suitable for solar floor radiant heating system.

Modular Energy Storage System for Alternative Energy Vehicles

Energy Technology Data Exchange (ETDEWEB)

Thomas, Janice [Magna Electronics Inc., Auburn Hills, MI (United States); Ervin, Frank [Magna Electronics Inc., Auburn Hills, MI (United States)

2012-05-15

An electrical vehicle environment was established to promote research and technology development in the area of high power energy management. The project incorporates a topology that permits parallel development of an alternative energy delivery system and an energy storage system. The objective of the project is to develop technologies, specifically power electronics, energy storage electronics and controls that provide efficient and effective energy management between electrically powered devices in alternative energy vehicles plugin electric vehicles, hybrid vehicles, range extended vehicles, and hydrogen-based fuel cell vehicles. In order to meet the project objectives, the Vehicle Energy Management System (VEMS) was defined and subsystem requirements were obtained. Afterwards, power electronics, energy storage electronics and controls were designed. Finally, these subsystems were built, tested individually, and integrated into an electric vehicle system to evaluate and optimize the subsystems performance. Phase 1 of the program established the fundamental test bed to support development of an electrical environment ideal for fuel cell application and the mitigation of many shortcomings of current fuel cell technology. Phase 2, continued development from Phase 1, focusing on implementing subsystem requirements, design and construction of the energy management subsystem, and the integration of this subsystem into the surrogate electric vehicle. Phase 2 also required the development of an Alternative Energy System (AES) capable of emulating electrical characteristics of fuel cells, battery, gen set, etc. Under the scope of the project, a boost converter that couples the alternate energy delivery system to the energy storage system was developed, constructed and tested. Modeling tools were utilized during the design process to optimize both component and system design. This model driven design process enabled an iterative process to track and evaluate the impact

Energy transition and phasing out nuclear

International Nuclear Information System (INIS)

Laponche, Bernard

2013-05-01

In the first part of this report, the author outlines and comments the need of an energy transition in the world: overview of world challenges (world energy consumption and its constraints, a necessary energy transition, new actors and new responsibilities), and describes the German example of an energy transition policy. In the second part, he presents and discusses the main reasons for phasing out nuclear: description of a nuclear plant operation (fission and chain reaction, heat production, production of radioactive elements, how to stop a nuclear reactor), safety and risk issues (protection arrangements, risk and consequence of a nuclear accident), issue of radioactive wastes, relationship between civil techniques and proliferation of nuclear weapons. In a third part, the author proposes an overview of the energy issue in France: final energy consumption, electricity production and consumption, primary energy consumption, characteristics of the French energy system (oil dependency, electricity consumption, and high share of nuclear energy in electricity production). In a last part, the author addresses the issue of energy transition in a perspective of phasing out nuclear: presentation of the Negawatt scenario, assessments made by Global Chance, main programmes of energy transition

Energy phase shift as mechanism for catalysis

KAUST Repository

Beke-Somfai, Tamás

2012-05-01

Catalysts are agents that by binding reactant molecules lower the energy barriers to chemical reaction. After reaction the catalyst is regenerated, its unbinding energy recruited from the environment, which is associated with an inevitable loss of energy. We show that combining several catalytic sites to become energetically and temporally phase-shifted relative to each other provides a possibility to sustain the overall reaction by internal \\'energy recycling\\', bypassing the need for thermal activation, and in principle allowing the system to work adiabatically. Using an analytical model for superimposed, phase-shifted potentials of F 1-ATP synthase provides a description integrating main characteristics of this rotary enzyme complex. © 2012 Elsevier B.V. All rights reserved.

Numerical study of finned heat pipe-assisted thermal energy storage system with high temperature phase change material

International Nuclear Information System (INIS)

Tiari, Saeed; Qiu, Songgang; Mahdavi, Mahboobe

2015-01-01

Highlights: • A finned heat pipe-assisted latent heat thermal energy storage system is studied. • The effects of heat pipes spacing and fins geometrical features are investigated. • Smaller heat pipes spacing and longer fins improve the melting rate. • The optimal heat pipe and fin arrangements are determined. - Abstract: In the present study, the thermal characteristics of a finned heat pipe-assisted latent heat thermal energy storage system are investigated numerically. A transient two-dimensional finite volume based model employing enthalpy-porosity technique is implemented to analyze the performance of a thermal energy storage unit with square container and high melting temperature phase change material. The effects of heat pipe spacing, fin length and numbers and the influence of natural convection on the thermal response of the thermal energy storage unit have been studied. The obtained results reveal that the natural convection has considerable effect on the melting process of the phase change material. Increasing the number of heat pipes (decreasing the heat pipe spacing) leads to the increase of melting rate and the decrease of base wall temperature. Also, the increase of fin length results in the decrease of temperature difference within the phase change material in the container, providing more uniform temperature distribution. It was also shown that number of the fins does not have a significant effect on the performance of the system

SHAFT-79, 2 Phase Flow in Porous Media for Geothermic Energy System

Energy Technology Data Exchange (ETDEWEB)

Pruess, K; Schroeder, R C [Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720 (United States)

1981-11-20

1 - Description of problem or function: SHAFT79 (Simultaneous Heat And Fluid Transport) is an integrated finite difference program for computing two-phase non-isothermal flow in porous media. Although designed for simulating production and injection in geothermal reservoirs, it is, or can be readily modified to be, applicable to other two-phase problems. SHAFT79 solves coupled mass and energy balance equations based on the following major assumptions: the physical system is a system of porous rock saturated with a one-component fluid in liquid and vapor form; all rock properties, except porosity, i.e., density, specific heat, thermal conductivity, and absolute permeability are independent of temperature, pressure, or vapor saturation: and liquid, vapor, and rock matrix are at the same temperature and pressure at all times. Capillary pressure is neglected. 2 - Method of solution: The solution method is an explicit-implicit integrated finite difference approach which allows a flexible geometric description because it does not distinguish between one-, two-, or three-dimensional regular or irregular geometries. The non-linear finite difference equations are solved using the Newton- Raphson method. In SHAFT79 a fluid table is used to provide the equilibrium thermodynamic properties of the fluid filling the void space - temperature, pressure, vapor saturation, heat conductivity, liquid and vapor viscosities, densities, specific interval energies - as functions of fluid density and fluid specific internal energy. All thermodynamic information including derivatives is obtained from the fluid table by bivariate interpolation. 3 - Restrictions on the complexity of the problem: SHAFT79 has been developed only for systems of water and rock. The fluid table covers most of the equation of state of water substance in the temperature range of 5 to 400 degrees C and the pressure range of 0.5 to 220 bar, which is adequate for most geothermal applications

SHAFT-79, 2 Phase Flow in Porous Media for Geothermic Energy System

International Nuclear Information System (INIS)

Pruess, K.; Schroeder, R.C.

1981-01-01

1 - Description of problem or function: SHAFT79 (Simultaneous Heat And Fluid Transport) is an integrated finite difference program for computing two-phase non-isothermal flow in porous media. Although designed for simulating production and injection in geothermal reservoirs, it is, or can be readily modified to be, applicable to other two-phase problems. SHAFT79 solves coupled mass and energy balance equations based on the following major assumptions: the physical system is a system of porous rock saturated with a one-component fluid in liquid and vapor form; all rock properties, except porosity, i.e., density, specific heat, thermal conductivity, and absolute permeability are independent of temperature, pressure, or vapor saturation: and liquid, vapor, and rock matrix are at the same temperature and pressure at all times. Capillary pressure is neglected. 2 - Method of solution: The solution method is an explicit-implicit integrated finite difference approach which allows a flexible geometric description because it does not distinguish between one-, two-, or three-dimensional regular or irregular geometries. The non-linear finite difference equations are solved using the Newton- Raphson method. In SHAFT79 a fluid table is used to provide the equilibrium thermodynamic properties of the fluid filling the void space - temperature, pressure, vapor saturation, heat conductivity, liquid and vapor viscosities, densities, specific interval energies - as functions of fluid density and fluid specific internal energy. All thermodynamic information including derivatives is obtained from the fluid table by bivariate interpolation. 3 - Restrictions on the complexity of the problem: SHAFT79 has been developed only for systems of water and rock. The fluid table covers most of the equation of state of water substance in the temperature range of 5 to 400 degrees C and the pressure range of 0.5 to 220 bar, which is adequate for most geothermal applications

Energy Efficiency Indicators for Assessing Construction Systems Storing Renewable Energy: Application to Phase Change Material-Bearing Façades

Directory of Open Access Journals (Sweden)

José A. Tenorio

2015-08-01

Full Text Available Assessing the performance or energy efficiency of a single construction element by itself is often a futile exercise. That is not the case, however, when an element is designed, among others, to improve building energy performance by harnessing renewable energy in a process that requires a source of external energy. Harnessing renewable energy is acquiring growing interest in Mediterranean climates as a strategy for reducing the energy consumed by buildings. When such reduction is oriented to lowering demand, the strategy consists in reducing the building’s energy needs with the use of construction elements able to passively absorb, dissipate, or accumulate energy. When reduction is pursued through M&E services, renewable energy enhances building performance. The efficiency of construction systems that use renewable energy but require a supplementary power supply to operate can be assessed by likening these systems to regenerative heat exchangers built into the building. The indicators needed for this purpose are particularly useful for designers, for they can be used to compare the efficiency or performance to deliver an optimal design for each building. This article proposes a series of indicators developed to that end and describes their application to façades bearing phase change materials (PCMs.

Nanoencapsulation of phase change materials for advanced thermal energy storage systems

Science.gov (United States)

Shchukina, E. M.; Graham, M.; Zheng, Z.

2018-01-01

Phase change materials (PCMs) allow the storage of large amounts of latent heat during phase transition. They have the potential to both increase the efficiency of renewable energies such as solar power through storage of excess energy, which can be used at times of peak demand; and to reduce overall energy demand through passive thermal regulation. 198.3 million tons of oil equivalent were used in the EU in 2013 for heating. However, bulk PCMs are not suitable for use without prior encapsulation. Encapsulation in a shell material provides benefits such as protection of the PCM from the external environment and increased specific surface area to improve heat transfer. This review highlights techniques for the encapsulation of both organic and inorganic PCMs, paying particular attention to nanoencapsulation (capsules with sizes energy release/uptake. PMID:29658558

Nanoencapsulation of phase change materials for advanced thermal energy storage systems.

Science.gov (United States)

Shchukina, E M; Graham, M; Zheng, Z; Shchukin, D G

2018-04-16

Phase change materials (PCMs) allow the storage of large amounts of latent heat during phase transition. They have the potential to both increase the efficiency of renewable energies such as solar power through storage of excess energy, which can be used at times of peak demand; and to reduce overall energy demand through passive thermal regulation. 198.3 million tons of oil equivalent were used in the EU in 2013 for heating. However, bulk PCMs are not suitable for use without prior encapsulation. Encapsulation in a shell material provides benefits such as protection of the PCM from the external environment and increased specific surface area to improve heat transfer. This review highlights techniques for the encapsulation of both organic and inorganic PCMs, paying particular attention to nanoencapsulation (capsules with sizes energy release/uptake.

Phase transition in finite systems

International Nuclear Information System (INIS)

Chomaz, Ph.; Duflot, V.; Duflot, V.; Gulminelli, F.

2000-01-01

In this paper we present a review of selected aspects of Phase transitions in finite systems applied in particular to the liquid-gas phase transition in nuclei. We show that the problem of the non existence of boundary conditions can be solved by introducing a statistical ensemble with an averaged constrained volume. In such an ensemble the microcanonical heat capacity becomes negative in the transition region. We show that the caloric curve explicitly depends on the considered transformation of the volume with the excitation energy and so does not bear direct informations on the characteristics of the phase transition. Conversely, partial energy fluctuations are demonstrated to be a direct measure of the equation of state. Since the heat capacity has a negative branch in the phase transition region, the presence of abnormally large kinetic energy fluctuations is a signal of the liquid gas phase transition. (author)

A Hybrid Estimator for Active/Reactive Power Control of Single-Phase Distributed Generation Systems with Energy Storage

DEFF Research Database (Denmark)

Pahlevani, Majid; Eren, Suzan; Guerrero, Josep M.

2016-01-01

This paper presents a new active/reactive power closed-loop control system for a hybrid renewable energy generation system used for single-phase residential/commercial applications. The proposed active/reactive control method includes a hybrid estimator, which is able to quickly and accurately es...

Heat storage system utilizing phase change materials government rights

Science.gov (United States)

Salyer, Ival O.

2000-09-12

A thermal energy transport and storage system is provided which includes an evaporator containing a mixture of a first phase change material and a silica powder, and a condenser containing a second phase change material. The silica powder/PCM mixture absorbs heat energy from a source such as a solar collector such that the phase change material forms a vapor which is transported from the evaporator to the condenser, where the second phase change material melts and stores the heat energy, then releases the energy to an environmental space via a heat exchanger. The vapor is condensed to a liquid which is transported back to the evaporator. The system allows the repeated transfer of thermal energy using the heat of vaporization and condensation of the phase change material.

Energy field of thermodynamic syste'ms

International Nuclear Information System (INIS)

Volchenkova, R.A.

1984-01-01

To reveal the qualitative and quantitative rules, regulating the properties of macro- and microsystems consideration is being given to the dependence of system enthalpy on environmental conditions. It was concluded that the dependence of material system enthalpy on temperature represents the energy field, containing the energy boundaries of phase states, described by exponential functions, in which the elements are arranged monotonically in the sequence of change of interatomic bonds, correlated with their physicomechanical properties; energy boundaries of phase states at that emanate from a single point, which is a reference a single point, which a reference one for the whole material system and determining its energy state in initial position. The presented energy field of thermodynamic systems enables to consider the change of their physicomechanical properties and energy state in dynamic process, depending on environmental parameters. Energy characteristics of single-component systems (W, Re, Hf, Nb, Mo etc) are given

The research of the beam phase and energy test system for DTL in the proton accelerator of CSNS

International Nuclear Information System (INIS)

Zhao Lei; Liu Shubin; An Qi

2009-01-01

China Spallation Neutron Source is now in the process of research and design,in which the proton accelerator is an important part. This beam phase and energy test system imports the signal from the Drift Tube Linac and computes its phase and energy, which is feedback to tune the beam. The signals to be processed here are modulated impulses of high frequency (repetition rate is 352.2 MHz, while the leading edge is only hundreds of ps), and the dynamic range of the amplitude is from 20 mv to 900 mv (peak to peak); therefore, special techniques are required to obtain its phase information. Moreover, to confirm the basic theory of corresponding techniques and evaluate their effects, some simulations are implemented in the platform of Matlab. (authors)

Programming models for energy-aware systems

Science.gov (United States)

Zhu, Haitao

Energy efficiency is an important goal of modern computing, with direct impact on system operational cost, reliability, usability and environmental sustainability. This dissertation describes the design and implementation of two innovative programming languages for constructing energy-aware systems. First, it introduces ET, a strongly typed programming language to promote and facilitate energy-aware programming, with a novel type system design called Energy Types. Energy Types is built upon a key insight into today's energy-efficient systems and applications: despite the popular perception that energy and power can only be described in joules and watts, real-world energy management is often based on discrete phases and modes, which in turn can be reasoned about by type systems very effectively. A phase characterizes a distinct pattern of program workload, and a mode represents an energy state the program is expected to execute in. Energy Types is designed to reason about energy phases and energy modes, bringing programmers into the optimization of energy management. Second, the dissertation develops Eco, an energy-aware programming language centering around sustainability. A sustainable program built from Eco is able to adaptively adjusts its own behaviors to stay on a given energy budget, avoiding both deficit that would lead to battery drain or CPU overheating, and surplus that could have been used to improve the quality of the program output. Sustainability is viewed as a form of supply and demand matching, and a sustainable program consistently maintains the equilibrium between supply and demand. ET is implemented as a prototyped compiler for smartphone programming on Android, and Eco is implemented as a minimal extension to Java. Programming practices and benchmarking experiments in these two new languages showed that ET can lead to significant energy savings for Android Apps and Eco can efficiently promote battery awareness and temperature awareness in real

An electromechanical swing-phase-controlled prosthetic knee joint for conversion of physiological energy to electrical energy: feasibility study.

Science.gov (United States)

Andrysek, Jan; Chau, Gilbert

2007-12-01

Microprocessor-controlled prostheses facilitate a more natural and efficient gait for individuals with above-knee amputations by continually adjusting the level of swing-phase damping. One caveat associated with these technologies is that the user must charge the onboard batteries on a daily basis. It is, therefore, the aim of this study to examine the feasibility of using an electromechanical system to provide prosthetic swing-phase damping and, concomitantly, the function of converting physiological energy that is normally dissipated during the swing phase, to electrical energy. Gait data from a single subject and data from a kinematic simulator were used to develop an empirical model. The findings in this study indicate that an electromagnetic system has appropriate characteristics for use in swing-phase control and also has the potential to recover energy under particular conditions.

Energy constraints in pulsed phase control of chaos

International Nuclear Information System (INIS)

Meucci, R.; Euzzor, S.; Zambrano, S.; Pugliese, E.; Francini, F.; Arecchi, F.T.

2017-01-01

Phase control of chaos is a powerful technique but little is known about its physical constraints, relevant for real systems. As a fact, it has not been explored whether this technique can also be applied when the controlling perturbation is not harmonic. Here we apply phase control on a driven double well Duffing oscillator using periodic rectangular pulsed perturbations instead of the classical sinusoidal perturbations. Experimental measurements and numerical simulations show that this kind of perturbation is also able to stabilize the chaotic orbits for an adequate selection of the phase. Furthermore, as the duty cycle of the perturbation (that is, the fraction of the time that the periodically pulsed control is active) is increased, two separate regimes occur. In the first one, the perturbations leading to stabilization of periodic solutions are of constant energy (taken as the product of the duty cycle and the amplitude) and in the second one, a saturation phenomenon occurs, implying that increasing energy values of the perturbations are wasted. Our results unveil the versatility of the pulsed phase control scheme and the importance of energy constraints.

Energy constraints in pulsed phase control of chaos

Energy Technology Data Exchange (ETDEWEB)

Meucci, R., E-mail: riccardo.meucci@ino.it [Istituto Nazionale di Ottica, Consiglio Nazionale delle Ricerche, Largo E. Fermi 6, 50125 Firenze (Italy); Euzzor, S. [Istituto Nazionale di Ottica, Consiglio Nazionale delle Ricerche, Largo E. Fermi 6, 50125 Firenze (Italy); Zambrano, S. [Università Vita-Salute San Raffaele, Via Olgettina 58, 20132 Milano (Italy); Pugliese, E. [Istituto Nazionale di Ottica, Consiglio Nazionale delle Ricerche, Largo E. Fermi 6, 50125 Firenze (Italy); Dipartimento di Scienze della Terra, Università di Firenze, Via G. La Pira 4, 50100 Firenze (Italy); Francini, F. [Istituto Nazionale di Ottica, Consiglio Nazionale delle Ricerche, Largo E. Fermi 6, 50125 Firenze (Italy); Arecchi, F.T. [Istituto Nazionale di Ottica, Consiglio Nazionale delle Ricerche, Largo E. Fermi 6, 50125 Firenze (Italy); Università di Firenze, Firenze (Italy)

2017-01-15

Phase control of chaos is a powerful technique but little is known about its physical constraints, relevant for real systems. As a fact, it has not been explored whether this technique can also be applied when the controlling perturbation is not harmonic. Here we apply phase control on a driven double well Duffing oscillator using periodic rectangular pulsed perturbations instead of the classical sinusoidal perturbations. Experimental measurements and numerical simulations show that this kind of perturbation is also able to stabilize the chaotic orbits for an adequate selection of the phase. Furthermore, as the duty cycle of the perturbation (that is, the fraction of the time that the periodically pulsed control is active) is increased, two separate regimes occur. In the first one, the perturbations leading to stabilization of periodic solutions are of constant energy (taken as the product of the duty cycle and the amplitude) and in the second one, a saturation phenomenon occurs, implying that increasing energy values of the perturbations are wasted. Our results unveil the versatility of the pulsed phase control scheme and the importance of energy constraints.

Integrated thermal treatment system sudy: Phase 2, Results

Energy Technology Data Exchange (ETDEWEB)

Feizollahi, F.; Quapp, W.J.

1995-08-01

This report presents the second phase of a study on thermal treatment technologies. The study consists of a systematic assessment of nineteen thermal treatment alternatives for the contact-handled mixed low-level waste (MLLW) currently stored in the US Department of Energy complex. The treatment alternatives consist of widely varying technologies for safely destroying the hazardous organic components, reducing the volume, and preparing for final disposal of the MLLW. The alternatives considered in Phase 2 were innovative thermal treatments with nine types of primary processing units. Other variations in the study examined the effect of combustion gas, air pollution control system design, and stabilization technology for the treatment residues. The Phase 1 study, the results of which have been published as an interim report, examined ten initial thermal treatment alternatives. The Phase 2 systems were evaluated in essentially the same manner as the Phase 2 systems. The assumptions and methods were the same as for the Phase 1 study. The quantities, and physical and chemical compositions, of the input waste used in he Phase 2 systems differ from those in the Phase 1 systems, which were based on a preliminary waste input database developed at the onset of the Integrated Thermal Treatment System study. The inventory database used in the Phase 2 study incorporates the latest US Department of Energy information. All systems, both primary treatment systems and subsystem inputs, have now been evaluated using the same waste input (2,927 lb/hr).

Integrated thermal treatment system sudy: Phase 2, Results

International Nuclear Information System (INIS)

Feizollahi, F.; Quapp, W.J.

1995-08-01

This report presents the second phase of a study on thermal treatment technologies. The study consists of a systematic assessment of nineteen thermal treatment alternatives for the contact-handled mixed low-level waste (MLLW) currently stored in the US Department of Energy complex. The treatment alternatives consist of widely varying technologies for safely destroying the hazardous organic components, reducing the volume, and preparing for final disposal of the MLLW. The alternatives considered in Phase 2 were innovative thermal treatments with nine types of primary processing units. Other variations in the study examined the effect of combustion gas, air pollution control system design, and stabilization technology for the treatment residues. The Phase 1 study, the results of which have been published as an interim report, examined ten initial thermal treatment alternatives. The Phase 2 systems were evaluated in essentially the same manner as the Phase 2 systems. The assumptions and methods were the same as for the Phase 1 study. The quantities, and physical and chemical compositions, of the input waste used in he Phase 2 systems differ from those in the Phase 1 systems, which were based on a preliminary waste input database developed at the onset of the Integrated Thermal Treatment System study. The inventory database used in the Phase 2 study incorporates the latest US Department of Energy information. All systems, both primary treatment systems and subsystem inputs, have now been evaluated using the same waste input (2,927 lb/hr)

A rule-based phase control methodology for a slider-crank wave energy converter power take-off system

Energy Technology Data Exchange (ETDEWEB)

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

2017-09-01

The slider crank is a proven mechanical linkage system with a long history of successful applications, and the slider-crank ocean wave energy converter (WEC) is a type of WEC that converts linear motion into rotation. This paper presents a control algorithm for a slider-crank WEC. In this study, a time-domain hydrodynamic analysis is adopted, and an AC synchronous machine is used in the power take-off system to achieve relatively high system performance. Also, a rule-based phase control strategy is applied to maximize energy extraction, making the system suitable for not only regular sinusoidal waves but also irregular waves. Simulations are carried out under regular sinusoidal wave and synthetically produced irregular wave conditions; performance validations are also presented with high-precision, real ocean wave surface elevation data. The influences of significant wave height, and peak period upon energy extraction of the system are studied. Energy extraction results using the proposed method are compared to those of the passive loading and complex conjugate control strategies; results show that the level of energy extraction is between those of the passive loading and complex conjugate control strategies, and the suboptimal nature of this control strategy is verified.

Energy study of heat pumps and energy storage at Cisco Systems International; Energiestudie warmtepompen en energieopslag Cisco Systems International

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-05-23

Cisco Systems International considers the use of energy storage in combination with heat pumps for the new office building in Amsterdam South-East, Netherlands. This office building has a floor space of 35,000 m{sup 2}. In a later phase this can be enlarged to 45,000 m{sup 2} (phase 1b) or 90,000 m{sup 2} (phase 2). This study is based on phase 1b. The mounting heat capacity is 2,760 kW and the cooling capacity is 7,045 kW. The annually cooling demand is estimated to be 30,400 MWh/a. The computer cooling forms a greater part of the cooling request (28,300 MWh/a). This study is a pilot study to the applicability of subsurface energy storage where heat pumps in the new office building are involved. However, nearby the Cisco location IKEA (furniture warehouse) has also planned an energy storage system. Therefore, the interaction between the two storage systems was examined. Cost effectiveness was analysed by comparison of the storage system with an energy system using conventional cooling machines and gas boilers. 5 refs.

Describing phase coexistence in systems with small phases

International Nuclear Information System (INIS)

Lovett, R

2007-01-01

Clusters of atoms can be studied in molecular beams and by computer simulation; 'liquid drops' provide elementary models for atomic nuclei and for the critical nuclei of nucleation theory. These clusters are often described in thermodynamic terms, but the behaviour of small clusters near a phase boundary is qualitatively different from the behaviour at a first order phase transition in idealized thermodynamics. In the idealized case the density and entropy show mathematically sharp discontinuities when the phase boundary is crossed. In large, but finite, systems, the phase boundaries become regions of state space wherein these properties vary rapidly but continuously. In small clusters with a large surface/volume ratio, however, the positive interfacial free energy makes it unlikely, even in states on phase boundaries, that a cluster will have a heterogeneous structure. What is actually seen in these states is a structure that fluctuates in time between homogeneous structures characteristic of the two sides of the phase boundary. That is, structural fluctuations are observed. Thermodynamics only predicts average properties; statistical mechanics is required to understand these fluctuations. Failure to distinguish thermodynamic properties and characterizations of fluctuations, particularly in the context of first order phase transitions, has led to suggestions that the classical rules for thermodynamic stability are violated in small systems and that classical thermodynamics provides an inconsistent description of these systems. Much of the confusion stems from taking statistical mechanical identifications of thermodynamic properties, explicitly developed for large systems, and applying them uncritically to small systems. There are no inconsistencies if thermodynamic properties are correctly identified and the distinction between thermodynamic properties and fluctuations is made clear

Phase relations and Gibbs energies of spinel phases and solid solutions in the system Mg-Rh-O

Energy Technology Data Exchange (ETDEWEB)

Jacob, K.T., E-mail: katob@materials.iisc.ernet.in [Department of Materials Engineering, Indian Institute of Science, Bangalore 560 012 (India); Prusty, Debadutta [Department of Materials Engineering, Indian Institute of Science, Bangalore 560 012 (India); Kale, G.M. [Institute for Materials Research, University of Leeds, Leeds, LS2 9JT (United Kingdom)

2012-02-05

Highlights: Black-Right-Pointing-Pointer Refinement of phase diagram for the system Mg-Rh-O and thermodynamic data for spinel compounds MgRh{sub 2}O{sub 4} and Mg{sub 2}RhO{sub 4} is presented. Black-Right-Pointing-Pointer A solid-state electrochemical cell is used for thermodynamic measurement. Black-Right-Pointing-Pointer An advanced design of the solid-state electrochemical cell incorporating buffer electrodes is deployed to minimize polarization of working electrode. Black-Right-Pointing-Pointer Regular solution model for the spinel solid solution MgRh{sub 2}O{sub 4} - Mg{sub 2}RhO{sub 4} based on ideal mixing of cations on the octahedral site is proposed. Black-Right-Pointing-Pointer Factors responsible for stabilization of tetravalent rhodium in spinel compounds are identified. - Abstract: Pure stoichiometric MgRh{sub 2}O{sub 4} could not be prepared by solid state reaction from an equimolar mixture of MgO and Rh{sub 2}O{sub 3} in air. The spinel phase formed always contained excess of Mg and traces of Rh or Rh{sub 2}O{sub 3}. The spinel phase can be considered as a solid solution of Mg{sub 2}RhO{sub 4} in MgRh{sub 2}O{sub 4}. The compositions of the spinel solid solution in equilibrium with different phases in the ternary system Mg-Rh-O were determined by electron probe microanalysis. The oxygen potential established by the equilibrium between Rh + MgO + Mg{sub 1+x}Rh{sub 2-x}O{sub 4} was measured as a function of temperature using a solid-state cell incorporating yttria-stabilized zirconia as an electrolyte and pure oxygen at 0.1 MPa as the reference electrode. To avoid polarization of the working electrode during the measurements, an improved design of the cell with a buffer electrode was used. The standard Gibbs energies of formation of MgRh{sub 2}O{sub 4} and Mg{sub 2}RhO{sub 4} were deduced from the measured electromotive force (e.m.f.) by invoking a model for the spinel solid solution. The parameters of the model were optimized using the measured

Towards 100% renewable energy systems: Uncapping power system flexibility

International Nuclear Information System (INIS)

Papaefthymiou, G.; Dragoon, Ken

2016-01-01

Relying almost entirely on energy from variable renewable resources such as wind and solar energy will require a transformation in the way power systems are planned and operated. This paper outlines the necessary steps in creating power systems with the flexibility needed to maintain stability and reliability while relying primarily on variable energy resources. These steps are provided in the form of a comprehensive overview of policies, technical changes, and institutional systems, organized in three development phases: an initial phase (penetration up to about 10%) characterized by relatively mild changes to conventional power system operations and structures; a dynamic middle phase (up to about 50% penetration) characterized by phasing out conventional generation and a concerted effort to wring flexibility from existing infrastructure; and the high penetration phase that inevitably addresses how power systems operate over longer periods of weeks or months when variable generation will be in either short supply, or in over-abundance. Although this transition is likely a decades-long and incremental process and depends on the specifics of each system, the needed policies, research, demonstration projects and institutional changes need to start now precisely because of the complexity of the transformation. The list of policy actions presented in this paper can serve as a guideline to policy makers on effectuating the transition and on tracking the preparedness of systems. - Highlights: •100% VRES systems: combined analysis of all related technical and policy challenges. •Transition elements: classification of the complete range of challenges in 9 elements. •Development regimes: policy actions in 3 VRES penetration regimes (low-medium-high). •Policies: comprehensive guideline and detailed presentation of policies per regime. •Roadmap: lists of actions per regime act as transition roadmap to 100% VRES systems.

Chemically and Thermally Stable High Energy Density Silicone Composites, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Thermal energy storage systems with 300 -- 1000 kJ/kg energy density through either phase changes or chemical heat absorption are sought by NASA. This proposed...

Phase-dependent dynamic potential of magnetically coupled two-degree-of-freedom bistable energy harvester.

Science.gov (United States)

Kim, Pilkee; Nguyen, Minh Sang; Kwon, Ojin; Kim, Young-Jin; Yoon, Yong-Jin

2016-09-28

A system of magnetically coupled oscillators has been recently considered as a promising compact structure to integrate multiple bistable energy harvesters (BEHs), but its design is not straightforward owing to its varying potential energy pattern, which has not been understood completely yet. This study introduces the concept of phase-dependent dynamic potential in a magnetically coupled BEH system with two degrees of freedom (DOFs) to explain the underlying principle of the complicated dynamics of the system. Through theoretical simulations and analyses, two distinct dynamic regimes, called the out-of-phase and in-phase mode regimes in this report, are found to exist in the frequency regions of the 1 st and 2 nd primary intrawell resonances. For the out-of-phase mode regime, the frequency displacement (and output power) responses of the 2-DOF BEH system exhibit typical double-well dynamics, whereas for the in-phase mode regime, only single-well dynamics is observed though the system is statically bistable. These dynamic regimes are also revealed to be caused by the difference in the dynamic potential energy trajectories propagating on a high-dimensional potential energy surface. The present approach to the dynamics of the 2-DOF BEH system can be extended and applied to higher-DOF systems, which sheds light on compact and efficient designs of magnetically coupled BEH chain structures.

Caspian energy phase II: Beyond 2005

International Nuclear Information System (INIS)

Shaffer, Brenda

2010-01-01

This article examines the major factors that will shape the second phase of Caspian oil and natural gas export. The article compares the prospects of the post-2005 period with the Caspian energy developments in the first decade and a half after independence. This article claims: One, political considerations will continue to play an important role in the decisions on export routes for and participants in Caspian energy production and export projects. However, those political considerations will produce different policies in phase two of Caspian energy production than they did in the first phase. Second, the relative influence and interest in the Caspian region of various global and regional powers have changed significantly from Caspian energy phase one to phase two. Third, the producers in the region are not as anxious for foreign investment as they were earlier. The major resources that will be developed in Caspian phase two are: new production of Azerbaijan's natural gas, extension to new markets and expansion of capacity of existing gas export routes; new production projects for Turkmenistan's natural gas and new pipelines; and additional Kazakhstani oil production and natural gas increased production and initiation of export.

[Study on a wireless energy transmission system for the noninvasive examination micro system inside alimentary tracts].

Science.gov (United States)

He, Xiu; Yan, Guo-Zheng; Wang, Fu-Min

2008-01-01

A wireless energy transmission system for the MEMS system inside alimentary tracts is reported here in the paper. It consists of an automatic frequency tracking circuit of phase lock loop and phase shift PWM control circuit. Experimental results show that the energy transmission system is capable of automatic frequency-tracking and transmission power-adjusting and has stable received energy.

Improving the Performance and Energy Efficiency of Phase Change Memory Systems

Institute of Scientific and Technical Information of China (English)

王琪; 李佳芮; 王东辉

2015-01-01

Phase change memory (PCM) is a promising technology for future memory thanks to its better scalability and lower leakage power than DRAM (dynamic random-access memory). However, adopting PCM as main memory needs to overcome its write issues, such as long write latency and high write power. In this paper, we propose two techniques to improve the performance and energy-efficiency of PCM memory systems. First, we propose a victim cache technique utilizing the existing buffer in the memory controller to reduce PCM memory accesses. The key idea is reorganizing the buffer into a victim cache structure (RBC) to provide additional hits for the LLC (last level cache). Second, we propose a chip parallelism-aware replacement policy (CPAR) for the victim cache to further improve performance. Instead of evicting one cache line once, CPAR evicts multiple cache lines that access different PCM chips. CPAR can reduce the frequent victim cache eviction and improve the write parallelism of PCM chips. The evaluation results show that, compared with the baseline, RBC can improve PCM memory system performance by up to 9.4% and 5.4% on average. Combing CPAR with RBC (RBC+CPAR) can improve performance by up to 19.0% and 12.1% on average. Moreover, RBC and RBC+CPAR can reduce memory energy consumption by 8.3%and 6.6%on average, respectively.

Analyse of possibilities of increasing housing energy efficiency by application of phase-changing materials

Directory of Open Access Journals (Sweden)

Vučeljić-Vavan Sanja

2009-01-01

Full Text Available Refurbishment of existing building stock using energy-saving phase-changing smart materials and technologies, in addition to improved indoor climatic conditions, offer an opportunity for increasing housing energy efficiency and value. This fast developing technology becomes increasingly cost-effective with much shorter payback periods. However, it is undertaken only on a limited scale; because of lack of knowledge about their changeable properties and dynamism in that they behave in response to energy fields. Main characteristics, which make them different form others, are: immediacy transience, self-actuation, selectivity and directness. Phase change processes invariably involve the absorbing, storing or releasing of large amounts of energy in the form of latent heat. These processes are reversible and phase-changing materials can undergo an unlimited number of cycles without degradation. Since phase-changing materials can be designed to absorb or release energy at predictable temperatures, they have naturally been explored for use in architecture as a way of helping deal with the thermal environment in a building. Technologies based on sealing phase-changing materials into small pellets have achieved widespread use in connection with radiant floor heating systems, phase change wallboards, mortar or facade systems. Thermal characteristics of existing buildings can be improved on increasing their thermal-stored mass by implementation products of phase-changing smart materials. In addition to contributing to carbon reduction and energy security, using phase-changing materials in the building sector stimulates innovations.

Phase transition signals of finite systems

International Nuclear Information System (INIS)

Duflot-Flandrois, Veronique

2001-01-01

Phase transitions are universal properties of interacting matter. They are well described if the considered system is infinite, by using standard thermodynamics. But in the case of small systems like atomic nuclei, this formalism cannot be applied anymore. Our aim is to propose a statistical mechanics approach in order to define the thermodynamical features of small open systems subject to non-saturating forces. We concentrate in particular on the definition and characterization for such systems of phase transitions belonging to the liquid gas universality class. Theoretical and experimental observables are defined to signal the occurrence and the order of this transition without any ambiguity. One of the most relevant and experimentally accessible observables consists in the study of kinetic energy fluctuations for a fixed value of the total deposited energy. In a first order phase transition such fluctuations become anomaly high and at the same time the size distribution appears to behave critically. All our results are obtained within numerical simulations of the lattice gas model with a nearest neighbors attractive interaction. Finally we check the influence of non-saturating forces, developing the specific example of the Coulomb interaction in the nucleus. Future improvements and perspectives at this work consist in the analysis of specific effects occurring in nuclei: isospin and quantum mechanics. (author) [fr

Restructuring the Energy System. Report of the Energy Commission

International Nuclear Information System (INIS)

1995-01-01

The commission was instructed to examine the current energy policy programs for restructuring and developing the energy system (i.e. phasing out nuclear power and moving to renewable sources) and to analyze the needs for changes; to propose measures for ensuring an efficient electricity supply under the new conditions of a liberalized electricity market; and to present proposals for a schedule for reorganizing the energy system. The report gives a full picture of the Swedish energy system including supply, consumption, prices, environmental impacts, R and D, and international aspects. The commission concludes that one nuclear power plant can be closed during the 1990's without upsetting the power balances. Phasing out all nuclear plants by year 2010 will create problems with the price levels of electricity supply, and will conflict with the CO 2 reduction objective. The proposals for economic control measures for performing the restructuring include: An environmental bonus (or investment support) for environmentally sound electricity production financed by an electricity tax, a tax on nuclear power increasing with the age of the reactors, a reorganization fund to finance new and environmentally acceptable electricity production. Also, energy research should be allotted greater resources, in particular for new technology for electricity production. The commission points towards the possibilities for reducing energy consumption, and especially electricity consumption. Space heating should gradually move away from electric heating. Examples are given on measures for improving energy efficiency and problems with financing such measures should be studied

Energy condensed packaged systems. Composition, production, properties

Directory of Open Access Journals (Sweden)

Igor L. Kovalenko

2015-03-01

Full Text Available In this paper it is presented the substantiation of choice of fuel phase composition and optimal technology of emulsion production on the basis of binary solution of ammonium and calcium nitrates, which provide the obtaining of energy condensed packaged systems with specified properties. The thermal decomposition of energy condensed systems on the basis of ammonium nitrate is investigated. It is shown that the fuel phase of emulsion systems should be based on esters of polyunsaturated acids or on combinations thereof with petroleum products. And ceresin or petroleum wax can be used as the structuring additive. The influence of the technology of energy condensed systems production on the physicochemical and detonation parameters of emulsion explosives is considered. It is shown the possibility of obtaining of emulsion systems with dispersion of 1.3...1.8 microns and viscosity higher than 103 Pa∙s in the apparatus of original design. The sensitizing effect of chlorinated paraffin CP-470 on the thermolysis of energy condensed emulsion system is shown. The composition and production technology of energy condensed packaged emulsion systems of mark Ukrainit-P for underground mining in mines not dangerous on gas and dust are developed.

Imaging phase holdup distribution of three phase flow systems using dual source gamma ray tomography

International Nuclear Information System (INIS)

Varma, Rajneesh; Al-Dahhan, Muthanna; O'Sullivan, Joseph

2008-01-01

Full text: Multiphase reaction and process systems are used in abundance in the chemical and biochemical industry. Tomography has been successfully employed to visualize the hydrodynamics of multiphase systems. Most of the tomography methods (gamma ray, x-ray and electrical capacitance and resistance) have been successfully implemented for two phase dynamic systems. However, a significant number of chemical and biochemical systems consists of dynamic three phases. Research effort directed towards the development of tomography techniques to image such dynamic system has met with partial successes for specific systems with applicability to limited operating conditions. A dual source tomography scanner has been developed that uses the 661 keV and 1332 keV photo peaks from the 137 Cs and 60 Co for imaging three phase systems. A new approach has been developed and applied that uses the polyenergetic Alternating Minimization (A-M) algorithm, developed by O'Sullivan and Benac (2007), for imaging the holdup distribution in three phases' dynamic systems. The new approach avoids the traditional post image processing approach used to determine the holdup distribution where the attenuation images of the mixed flow obtained from gamma ray photons of two different energies are used to determine the holdup of three phases. In this approach the holdup images are directly reconstructed from the gamma ray transmission data. The dual source gamma ray tomography scanner and the algorithm were validated using a three phase phantom. Based in the validation, three phase holdup studies we carried out in slurry bubble column containing gas liquid and solid phases in a dynamic state using the dual energy gamma ray tomography. The key results of the holdup distribution studies in the slurry bubble column along with the validation of the dual source gamma ray tomography system would be presented and discussed

The cost of the nuclear energy-turnaround. An early nuclear phase-out and its consequences

International Nuclear Information System (INIS)

Baran, Metin

2013-01-01

The booklet on the consequences of an early nuclear phase-out includes a description of the value creation strategy in the electricity market and the basic relations of the electricity price formation and a survey and evaluation of selected studies. The analysis was performed for the following studies: Energy policy scenarios for a nuclear phase-out in Germany; Economic consequences of a nuclear phase-out in Germany; Transformation of the electricity production systems with a forced nuclear phase-out - a contribution on sustainable energy systems following the reactor accident of Fukushima; Cost of a nuclear phase-out until 2022 in Germany and Bavaria.

Three-phase Photovoltaic Systems

DEFF Research Database (Denmark)

Kerekes, Tamas; Sera, Dezso; Máthé, Lászlo

2015-01-01

, detailing the different photovoltaic inverter structures and topologies as well as discussing the different control layers within a grid-connected photovoltaic plant. Modulation schemes for various photovoltaic inverter topologies, grid synchronization, current control, active and reactive power control......Photovoltaic technology has experienced unprecedented growth in the last two decades, transforming from mainly off-grid niche generation to a major renewable energy technology, reaching approximately 180 GW of capacity worldwide at the end of 2014. Large photovoltaic power plants interfacing...... the grid through a three-phase power electronic converter are now well on the way to becoming a major player in the power system in many countries. Therefore, this article gives an overview of photovoltaic systems with a focus on three-phase applications, presenting these both from a hardware point of view...

INTEGRATED ENERGY EFFICIENT WINDOW-WALL SYSTEMS

Energy Technology Data Exchange (ETDEWEB)

Michael Arney, Ph.D.

2002-12-31

The building industry faces the challenge of reducing energy use while simultaneously improving construction methods and marketability. This paper describes the first phase of a project to address these concerns by designing an Integrated Window Wall System (IWWS) that can be commercialized. This work builds on previous research conducted during the 1990's by Lawrence Berkeley national Laboratories (LBNL). During this phase, the objective was to identify appropriate technologies, problems and issues and develop a number of design concepts. Four design concepts were developed into prototypes and preliminary energy analyses were conducted Three of these concepts (the foam wall, steel wall, and stiffened plate designs) showed particular potential for meeting the project objectives and will be continued into a second phase where one or two of the systems will be brought closer to commercialization.

The Influence of a Radiant Panel System with Integrated Phase Change Material on Energy Use and Thermal Indoor Environment

DEFF Research Database (Denmark)

Nielsen, Lin Flemming; Bourdakis, Eleftherios; Kazanci, Ongun Berk

2018-01-01

This study examined the effect on energy use and thermal comfort when combining microencapsulated phase change material (PCM) with radiant ceiling panels in a two-person office. The performance of the system was studied during the cooling season in the climates of Copenhagen, Denmark, and Rome...

Continuous solid-state phase transitions in energy storage materials with orientational disorder – Computational and experimental approach

International Nuclear Information System (INIS)

Singh, Harpreet; Talekar, Anjali; Chien, Wen-Ming; Shi, Renhai; Chandra, Dhanesh; Mishra, Amrita; Tirumala, Muralidhar; Nelson, Daryl J.

2015-01-01

We report on TES (thermal energy storage) in new CT (continuous phase transitions) in multicomponent tetrahederally configured (orientationally disordered) crystals of NPG-neopentylglycol-C 5 H 12 O 2 , PG-pentaglycerine-C 5 H 12 O 3 , and PE-pentaerythritol-C 5 H 12 O 4 . This discovery is applicable in thermal energy storage in many systems which do not require conventional isothermal first-order phase transition energy storage. The above compounds exhibit polymorphs of orientationally disordered phases in which O–H…O bond rotation around the C–C bond stores significant amount of energy; for example, in PE 41.26 kJ/mol are absorbed isothermally during solid–solid transitions. In this paper we show, anisothermal continuous phase transitions (CT), due to compositional changes with changes in temperature, associated with a measurable amount of energy, not reported earlier. The correlation of phase stability regions in pseudo-binaries, calculated from ternary NPG–PG–PE phase diagrams, is validated by experimental ternary DSC (differential scanning calorimetry) and in-situ x-ray diffraction data. We established equations for determining the CT in a temperature range, and their respective enthalpies of transitions for any composition of the ternaries. Thermodynamic calculations of the Gibbs energies of the solution phases are modeled as substitutional solid solutions, in which the excess Gibbs energies are expressed by the Redlich–Kister–Muggianu polynomial. There is excellent agreement between the experimental and CALPHAD calculated data. - Highlights: • Continuous phase transition (CT) thermal energy storage in organic ternary system. • Anisothermal temperature ramping leads to CT transitions as per lever rule. • Orientationally disordered phases store energy in O–H…O bond rotation/oscillation. • Validated calculated data with measured thermodynamic properties in ternary system. • Used CALPHAD methodology to calculate Gibbs energies of

Two-phase systems. Fundamentals and industrial applications

International Nuclear Information System (INIS)

Woillez, Jacques

2014-01-01

Two-phase flows are omnipresent in industrial processes in different sectors with the behaviour and control of non-mixing mixtures of gas and liquids, of several liquids, of solids and fluids which are present in the production of raw materials, in the environment, in energy production, in chemistry, in pharmaceutical or food industry. The author presents the fundamentals elements which are needed to perform hardware predictive calculations and to understand typical phenomena associated with these flows. The chapters address fluids mechanics (movement equations, Bernoulli equation, load losses, turbulence, heat exchange coefficients, thermodynamics, compressible flows), two-phase systems (characteristic values, modes of appearance of two-phase flows, conduct flows, suspension mechanics, mass transfers, similarity, numerical simulation), the applications (energy production, agitation and mixing, phase separation, sprays), and peculiar phenomena (Marangoni effect, the tea cup effect, entry jets, water hammer effect, sound speed, two-phase pumping, fluidization)

Phase synchronization of multiple klystrons in RF system

International Nuclear Information System (INIS)

Kwon, S.; Regan, A.; Wang, Y.M.; Rohlev, T.

1998-01-01

The Low Energy Demonstration Accelerator (LEDA) being constructed at Los Alamos National Laboratory will serve as the prototype for the low energy section of the Acceleration Production of Tritium (APT) accelerator. The first LEDA RF system includes three, 1.2 MW, 350 MHz, continuous wave, klystrons driving a radio frequency quadrupole (RFQ). A phase control loop is necessary for each individual klystron in order to guarantee the phase matching of these klystrons. To meet this objective, they propose adaptive PI controllers which are based on simple adaptive control. These controllers guarantee not only phase matching but also amplitude matching

Heat pipe based cold energy storage systems for datacenter energy conservation

International Nuclear Information System (INIS)

Singh, Randeep; Mochizuki, Masataka; Mashiko, Koichi; Nguyen, Thang

2011-01-01

system concept. -- Highlights: → The paper presents novel concept for datacenter thermal management using heat-pipe based energy conservation system utilizing cold ambient energy. → Two type of system: ice storage and cold water storage has been identified and discussed. → Ice storage or two-phase system can provide long term storage and can be used as datacenter emergency support system. → Cold water or single-phase system can be employed as precooler for coolant before it is cooled by electrical chiller. → These two types of storage approaches can help to minimize chiller electrical load thus saving electricity and associated cost.

Energy Efficiency Enhancement of Photovoltaics by Phase Change Materials through Thermal Energy Recovery

Directory of Open Access Journals (Sweden)

Ahmad Hasan

2016-09-01

Full Text Available Photovoltaic (PV panels convert a certain amount of incident solar radiation into electricity, while the rest is converted to heat, leading to a temperature rise in the PV. This elevated temperature deteriorates the power output and induces structural degradation, resulting in reduced PV lifespan. One potential solution entails PV thermal management employing active and passive means. The traditional passive means are found to be largely ineffective, while active means are considered to be energy intensive. A passive thermal management system using phase change materials (PCMs can effectively limit PV temperature rises. The PCM-based approach however is cost inefficient unless the stored thermal energy is recovered effectively. The current article investigates a way to utilize the thermal energy stored in the PCM behind the PV for domestic water heating applications. The system is evaluated in the winter conditions of UAE to deliver heat during water heating demand periods. The proposed system achieved a ~1.3% increase in PV electrical conversion efficiency, along with the recovery of ~41% of the thermal energy compared to the incident solar radiation.

Bateman's dual system revisited: quantization, geometric phase and relation with the ground-state energy of the linear harmonic oscillator

International Nuclear Information System (INIS)

Blasone, Massimo; Jizba, Petr

2004-01-01

By using the Feynman-Hibbs prescription for the evolution amplitude, we quantize the system of a damped harmonic oscillator coupled to its time-reversed image, known as Bateman's dual system. The time-dependent quantum states of such a system are constructed and discussed entirely in the framework of the classical theory. The corresponding geometric (Pancharatnam) phase is calculated and found to be directly related to the ground-state energy of the 1D linear harmonic oscillator to which the 2D system reduces under appropriate constraint

LINEAR SOLVATION ENERGY RELATIONSHIPS FOR CHARACTERIZATION OF MLC SYSTEMS WITH SODIUM DODECYL SULPHATE MOBILE PHASES MODIFIED BY ALIPHATIC ALCOHOLS OR CARBOXYLIC ACIDS

NARCIS (Netherlands)

Markov, Vadym V.; Boichenko, Alexander P.; Loginova, Lidia P.

2012-01-01

The Linear Solvation Energy Relationships (LSER) have been successfully used for the modeling of partition and retention of the set of test compounds in different systems. The properties of micellar chromatographic systems with the mobile phases on the basis of sodium dodecylsulphate modified (ODS)

The geometric phase in two-level atomic systems

International Nuclear Information System (INIS)

Tian Mingzhen; Barber, Zeb W.; Fischer, Joe A.; Randall Babbitt, Wm.

2004-01-01

We report the observation of the geometric phase in a closed two-level atomic system using stimulated photon echoes. The two-level system studied consists of the two-electronic energy levels ( 3 H 4 and 3 H 6 ) of Tm 3+ doped in YAG crystal. When a two-level atom at an arbitrary superposition state is excited by a pair of specially designed laser pulses, the excited state component gains a relative phase with respect to the ground state component. We identified the phase shift to be of pure geometric nature. The dynamic phase associated to the driving Hamiltonian is unchanged. The experiment results of the phase change agree with the theory to the extent of the measurement limit

Integrated thermal treatment system study -- Phase 2 results. Revision 1

Energy Technology Data Exchange (ETDEWEB)

Feizollahi, F.; Quapp, W.J.

1996-02-01

This report presents the second phase of a study on thermal treatment technologies. The study consists of a systematic assessment of nineteen thermal treatment alternatives for the contact-handled mixed low-level waste (MLLW) currently stored in the US Department of Energy complex. The treatment alternatives consist of widely varying technologies for safely destroying the hazardous organic components, reducing the volume, and preparing for final disposal of the MLLW. The alternatives considered in Phase 2 were innovative thermal treatments with nine types of primary processing units. Other variations in the study examined the effect of combustion gas, air pollution control system design, and stabilization technology for the treatment residues. The Phase 1 study examined ten initial thermal treatment alternatives. The Phase 2 systems were evaluated in essentially the same manner as the Phase 1 systems. The alternatives evaluated were: rotary kiln, slagging kiln, plasma furnace, plasma gasification, molten salt oxidation, molten metal waste destruction, steam gasification, Joule-heated vitrification, thermal desorption and mediated electrochemical oxidation, and thermal desorption and supercritical water oxidation. The quantities, and physical and chemical compositions, of the input waste used in the Phase 2 systems differ from those in the Phase 1 systems, which were based on a preliminary waste input database developed at the onset of the Integrated Thermal Treatment System study. The inventory database used in the Phase 2 study incorporates the latest US Department of Energy information. All systems, both primary treatment systems and subsystem inputs, have now been evaluated using the same waste input (2,927 lb/hr). 28 refs., 88 figs., 41 tabs.

Integrated thermal treatment system study -- Phase 2 results. Revision 1

International Nuclear Information System (INIS)

Feizollahi, F.; Quapp, W.J.

1996-02-01

This report presents the second phase of a study on thermal treatment technologies. The study consists of a systematic assessment of nineteen thermal treatment alternatives for the contact-handled mixed low-level waste (MLLW) currently stored in the US Department of Energy complex. The treatment alternatives consist of widely varying technologies for safely destroying the hazardous organic components, reducing the volume, and preparing for final disposal of the MLLW. The alternatives considered in Phase 2 were innovative thermal treatments with nine types of primary processing units. Other variations in the study examined the effect of combustion gas, air pollution control system design, and stabilization technology for the treatment residues. The Phase 1 study examined ten initial thermal treatment alternatives. The Phase 2 systems were evaluated in essentially the same manner as the Phase 1 systems. The alternatives evaluated were: rotary kiln, slagging kiln, plasma furnace, plasma gasification, molten salt oxidation, molten metal waste destruction, steam gasification, Joule-heated vitrification, thermal desorption and mediated electrochemical oxidation, and thermal desorption and supercritical water oxidation. The quantities, and physical and chemical compositions, of the input waste used in the Phase 2 systems differ from those in the Phase 1 systems, which were based on a preliminary waste input database developed at the onset of the Integrated Thermal Treatment System study. The inventory database used in the Phase 2 study incorporates the latest US Department of Energy information. All systems, both primary treatment systems and subsystem inputs, have now been evaluated using the same waste input (2,927 lb/hr). 28 refs., 88 figs., 41 tabs

Technical Analysis of the Hydrogen Energy Station Concept, Phase I and Phase II

Energy Technology Data Exchange (ETDEWEB)

TIAX, LLC

2005-05-04

Phase I Due to the growing interest in establishing a domestic hydrogen infrastructure, several hydrogen fueling stations already have been established around the country as demonstration units. While these stations help build familiarity with hydrogen fuel in their respective communities, hydrogen vehicles are still several years from mass production. This limited number of hydrogen vehicles translates to a limited demand for hydrogen fuel, a significant hurdle for the near-term establishment of commercially viable hydrogen fueling stations. By incorporating a fuel cell and cogeneration system with a hydrogen fueling station, the resulting energy station can compensate for low hydrogen demand by providing both hydrogen dispensing and combined heat and power (CHP) generation. The electrical power generated by the energy station can be fed back into the power grid or a nearby facility, which in turn helps offset station costs. Hydrogen production capacity not used by vehicles can be used to support building heat and power loads. In this way, an energy station can experience greater station utility while more rapidly recovering capital costs, providing an increased market potential relative to a hydrogen fueling station. At an energy station, hydrogen is generated on-site. Part of the hydrogen is used for vehicle refueling and part of the hydrogen is consumed by a fuel cell. As the fuel cell generates electricity and sends it to the power grid, excess heat is reclaimed through a cogeneration system for use in a nearby facility. Both the electrical generation and heat reclamation serve to offset the cost of purchasing the equivalent amount of energy for nearby facilities and the energy station itself. This two-phase project assessed the costs and feasibility of developing a hydrogen vehicle fueling station in conjunction with electricity and cogenerative heat generation for nearby Federal buildings. In order to determine which system configurations and operational

Optically-controlled long-term storage and release of thermal energy in phase-change materials.

Science.gov (United States)

Han, Grace G D; Li, Huashan; Grossman, Jeffrey C

2017-11-13

Thermal energy storage offers enormous potential for a wide range of energy technologies. Phase-change materials offer state-of-the-art thermal storage due to high latent heat. However, spontaneous heat loss from thermally charged phase-change materials to cooler surroundings occurs due to the absence of a significant energy barrier for the liquid-solid transition. This prevents control over the thermal storage, and developing effective methods to address this problem has remained an elusive goal. Herein, we report a combination of photo-switching dopants and organic phase-change materials as a way to introduce an activation energy barrier for phase-change materials solidification and to conserve thermal energy in the materials, allowing them to be triggered optically to release their stored latent heat. This approach enables the retention of thermal energy (about 200 J g -1 ) in the materials for at least 10 h at temperatures lower than the original crystallization point, unlocking opportunities for portable thermal energy storage systems.

Evaluation of regenerative phase change drywalls: low-energy building application

Energy Technology Data Exchange (ETDEWEB)

Darkwa, K. [Nottingham Trent Unv., Applied Energy and Environmental Engineering Unit, Nottingham (United Kingdom)

1999-07-01

An integrated phase change drywall system has been analytically evaluated for low-energy building applications. The mathematical model indicates that it is possible to attain higher levels of thermal performance and efficiency with lower values of transfer units (NTU). Even though the model does not take into account the variable nature of the thermophysical properties of phase change materials (PCMs), reasonable thermal performance is achievable. Experimental validation is therefore recommended. (Author)

Exploring the Nuclear Phase Diagram with Beam Energy Scans

International Nuclear Information System (INIS)

Horvat, Stephen

2017-01-01

The nuclear phase diagram is mapped using beam energy scans of relativistic heavy-ion collisions. This mapping is possible because different collision energies develop along different trajectories through the phase diagram. High energy collisions will evolve though a crossover phase transition according to lattice QCD, but lower collision energies may traverse a first order phase transition. There are hints for this first order phase transition and its critical endpoint, but further measurements and theoretical guidance is needed. In addition to mapping the phase transition, beam energy scans allow us to see if we can turn off the signatures of deconfinement. If an observable is a real signature for the formation of the deconfined state called quark-gluon plasma, then it should turn off at sufficiently low collision energies. In this summary talk I will show the current state of the field using beam energy scan results from RHIC and SPS, I will show where precise theoretical guidance is needed for understanding recent measurements, and I will motivate the need for more data and new measurements from FAIR, NICA, RHIC, and the SPS. (paper)

NSRL 200 MeV linac beam energy stabilization system

International Nuclear Information System (INIS)

Huang Guirong; Pei Yuanji; Dong Sai

2001-01-01

By using the computer image processing technology and RF phase auto-shifting system, the ESS (Energy Stabilization System) was applied to 200 MeV Linac. the ESS adjusts beam energy automatically in a range of +-4 MeV. After adjustment beam energy stability is improved to +-6%

Efficient Phase Locking of Fiber Amplifiers Using a Low-Cost and High-Damage-Threshold Phase Control System

International Nuclear Information System (INIS)

Pu, Zhou; Yan-Xing, Ma; Xiao-Lin, Wang; Hao-Tong, Ma; Xiao-Jun, Xu; Ze-Jin, Liu

2010-01-01

We propose a low-cost and high-damage-threshold phase control system that employs a piezoelectric ceramic transducer modulator controlled by a stochastic parallel gradient descent algorithm. Efficient phase locking of two fiber amplifiers is demonstrated. Experimental results show that energy encircled in the target pinhole is increased by a factor of 1.76 and the visibility of the fringe pattern is as high as 90% when the system is in close-loop. The phase control system has potential in phase locking of large-number and high-power fiber laser endeavors. (fundamental areas of phenomenology (including applications))

Power and phase monitoring system for the lower hybrid phased array heating system on ATC machine

International Nuclear Information System (INIS)

Reed, B.W.

1975-01-01

A four waveguide phased array slow wave structure has been constructed to couple microwave energy into plasma in the ATC Tokamac at Princeton. Theory has indicated that the coupling of power into the plasma column is a strong function of the imposed fourier spectrum at the antenna aperture. To optimize heating, and to verify theoretical results, a precision amplitude and phase monitoring system has been designed and constructed. The system data output is routed to an IBM 1800 computer where the fourier spectrum in n/sub parallel/ space is computed for discrete increments of time during an RF pulse. Computer output data is used to update the adjustment of transmission line parameters in between pulses

Development of a solar-hydrogen hybrid energy system

International Nuclear Information System (INIS)

Sebastian, P.J.; Gamboa, S.A.; Vejar, Set; Campos, J.

2009-01-01

Full text: The details of the development of a PV-hydrogen hybrid energy system is presented. An arrangement of photovoltaic modules (125 W/module) was established to provide 9 kW installed power in a three-phase configuration at 127 Vrms/phase. A 5 kW fuel cell system (hydrogen/oxygen) operate as a dynamic backup of the photovoltaic system. The autonomous operation of the hybrid power system implies the production of hydrogen by electrolysis. The hydrogen is produced by water electrolysis using an electrolyzer of 1 kW power. The electrical energy used to produce hydrogen is supplied from solar panels by using 1kW of photovoltaic modules. The photovoltaic modules are installed in a sun-tracker arrangement for increasing the energy conversion efficiency. The hydrogen is stored in solar to electric commercial metal hydride based containers and supplied to the fuel cell. The hybrid system is monitored by internet and some dynamic characteristics such as demanding power, energy and power factor could be analyzed independently from the system. Some energy saving recommendations has been implemented as a pilot program at CIE-UNAM to improve the efficient use of clean energy in normal operating conditions in offices and laboratories. (author)

Thermodynamic calculation of phase equilibria of the U-Ga and U-W systems

International Nuclear Information System (INIS)

Wang, J.; Liu, X.J.; Wang, C.P.

2008-01-01

The thermodynamic assessments of the U-Ga and U-W systems have been carried out by using the CALPHAD (calculation of phase diagrams) method using experimental data including thermodynamic properties and phase equilibria. Gibbs free energies of the solution phases were described by the subregular solution models with the Redlich-Kister equation, and those of the intermetallic compounds were described by the sublattice models. A consistent set of thermodynamic parameters has been derived for the Gibbs free energy of each phase in the U-Ga and U-W binary systems, respectively. The calculated phase diagrams and thermodynamic properties in the U-Ga and U-W systems are in good agreement with experimental data

Zero-Voltage Ride-Through Capability of Single-Phase Grid-Connected Photovoltaic Systems

Directory of Open Access Journals (Sweden)

Zhen Zhang

2017-03-01

Full Text Available Distributed renewable energy systems play an increasing role in today’s energy paradigm. Thus, intensive research activities have been centered on improving the performance of renewable energy systems, including photovoltaic (PV systems, which should be of multiple-functionality. That is, the PV systems should be more intelligent in the consideration of grid stability, reliability, and fault protection. Therefore, in this paper, the performance of single-phase grid-connected PV systems under an extreme grid fault (i.e., when the grid voltage dips to zero is explored. It has been revealed that combining a fast and accurate synchronization mechanism with appropriate control strategies for the zero-voltage ride-through (ZVRT operation is mandatory. Accordingly, the representative synchronization techniques (i.e., the phase-locked loop (PLL methods in the ZVRT operation are compared in terms of detection precision and dynamic response. It shows that the second-order generalized integrator (SOGI-PLL is a promising solution for single-phase systems in the case of fault ride-through. A control strategy by modifying the SOGI-PLL scheme is then introduced to single-phase grid-connected PV systems for ZVRT operation. Simulations are performed to verify the discussions. The results have demonstrated that the proposed method can help single-phase PV systems to temporarily ride through zero-voltage faults with good dynamics.

Fuzzy droop control loops adjustment for stored energy balance in distributed energy storage system

DEFF Research Database (Denmark)

Aldana, Nelson Leonardo Diaz; Wu, Dan; Dragicevic, Tomislav

2015-01-01

system, in order to smooth the variations at the prime energy generator. In this paper, a decentralized strategy based on fuzzy logic is proposed in order to balance the state of charge of distributed energy storage systems in lowvoltage three phase AC microgrid. The proposed method weights the action...

Gibbs Energy Modeling of Digenite and Adjacent Solid-State Phases

Science.gov (United States)

Waldner, Peter

2017-08-01

All sulfur potential and phase diagram data available in the literature for solid-state equilibria related to digenite have been assessed. Thorough thermodynamic analysis at 1 bar total pressure has been performed. A three-sublattice approach has been developed to model the Gibbs energy of digenite as a function of composition and temperature using the compound energy formalism. The Gibbs energies of the adjacent solid-state phases covelitte and high-temperature chalcocite are also modeled treating both sulfides as stoichiometric compounds. The novel model for digenite offers new interpretation of experimental data, may contribute from a thermodynamic point of view to the elucidation of the role of copper species within the crystal structure and allows extrapolation to composition regimes richer in copper than stoichiometric digenite Cu2S. Preliminary predictions into the ternary Cu-Fe-S system at 1273 K (1000 °C) using the Gibbs energy model of digenite for calculating its iron solubility are promising.

Energy management based on AM/FM/GIS for phase balancing application on distribution systems

International Nuclear Information System (INIS)

Kuo, C.-C.; Chao, Y.-T.

2010-01-01

Unbalanced feeder systems may deteriorate of power quality, and increase investment and operating costs for distribution systems. The phase swapping method recommends re-phasing circuits of laterals and transformers for making the current and voltage balanced and also reducing feeder loss and voltage drop. In this paper, an application program, based on the automated mapping/facilities management/ geographic information system (AM/FM/GIS) is developed which contains a function of automatically computing Z-bus, load flow and phase balancing of feeders with phase swapping by using easily selecting of feeder on a graphic user interface application. Therefore, the relative data need not be keyed in manually. The presented phase balancing algorithm are based on database and related data structures developed on the AM/FM/GIS and Visual Basic software, which can be integrated into the Tai-Power distribution automation system. Then, the phase balancing algorithm is designed to handle the load patterns and the load of transformers that connect specific feeders when evaluating phase swaps that will result in reduced daily circuit losses over all load points. The proposed application not only can effectively reduce the circuit loss and improves phase balancing, but also enhances power quality efficiently under easily using environment.

Performance analysis of an integrated energy storage and energy upgrade thermochemical solid–gas sorption system for seasonal storage of solar thermal energy

International Nuclear Information System (INIS)

Li, Tingxian; Wang, Ruzhu; Kiplagat, Jeremiah K.; Kang, YongTae

2013-01-01

An innovative dual-mode thermochemical sorption energy storage method is proposed for seasonal storage of solar thermal energy with little heat losses. During the charging phase in summer, solar thermal energy is stored in form of chemical bonds resulting from thermochemical decomposition process, which enables the stored energy to be kept several months at ambient temperature. During the discharging phase in winter, the stored thermal energy is released in the form of chemical reaction heat resulting from thermochemical synthesis process. Thermodynamic analysis showed that the advanced dual-mode thermochemical sorption energy storage is an effective method for the long-term seasonal storage of solar energy. A coefficient of performance (COP h ) of 0.6 and energy density higher than 1000 kJ/kg of salt can be attained from the proposed system. During the discharging phase at low ambient temperatures, the stored thermal energy can be upgraded by use of a solid–gas thermochemical sorption heat transformer cycle. The proposed thermochemical sorption energy storage has distinct advantages over the conventional sensible heat and latent heat storage, such as higher energy storage density, little heat losses, integrated energy storage and energy upgrade, and thus it can contribute to improve the seasonal utilization of solar thermal energy. - Highlights: ► A dual-mode solid thermochemical sorption is proposed for seasonal solar thermal energy storage. ► Energy upgrade techniques into the energy storage system are integrated. ► Performance of the proposed seasonal energy storage system is evaluated. ► Energy density and COP h from the proposed system are as high as 1043 kJ/kg of salt and 0.60, respectively

Large resistivity modulation in mixed-phase metallic systems.

Science.gov (United States)

Lee, Yeonbae; Liu, Z Q; Heron, J T; Clarkson, J D; Hong, J; Ko, C; Biegalski, M D; Aschauer, U; Hsu, S L; Nowakowski, M E; Wu, J; Christen, H M; Salahuddin, S; Bokor, J B; Spaldin, N A; Schlom, D G; Ramesh, R

2015-01-07

In numerous systems, giant physical responses have been discovered when two phases coexist; for example, near a phase transition. An intermetallic FeRh system undergoes a first-order antiferromagnetic to ferromagnetic transition above room temperature and shows two-phase coexistence near the transition. Here we have investigated the effect of an electric field to FeRh/PMN-PT heterostructures and report 8% change in the electrical resistivity of FeRh films. Such a 'giant' electroresistance (GER) response is striking in metallic systems, in which external electric fields are screened, and thus only weakly influence the carrier concentrations and mobilities. We show that our FeRh films comprise coexisting ferromagnetic and antiferromagnetic phases with different resistivities and the origin of the GER effect is the strain-mediated change in their relative proportions. The observed behaviour is reminiscent of colossal magnetoresistance in perovskite manganites and illustrates the role of mixed-phase coexistence in achieving large changes in physical properties with low-energy external perturbation.

Energy Saving Potentials of Phase Change Materials Applied to Lightweight Building Envelopes

Directory of Open Access Journals (Sweden)

Yoon-Bok Seong

2013-10-01

Full Text Available Phase change materials (PCMs have been considered as an innovative technology that can reduce the peak loads and heating, ventilating and air conditioning (HVAC energy consumption in buildings. Basically they are substances capable of storing or releasing thermal energy as latent heat. Because the amount of latent heat absorbed or released is much larger than the sensible heat, the application of PCMs in buildings has significant potential to reduce energy consumption. However, because each PCM has its own phase change temperature, which is the temperature at which latent heat is absorbed or released, it is important to use an appropriate PCM for the purpose of building envelope design. Therefore, this paper aims to investigate the energy saving potentials in buildings when various PCMs with different phase change temperatures are applied to a lightweight building envelope by analyzing the thermal load characteristics. As results, the annual heating load increased at every phase change temperature, but the peak heating load decreased by 3.19% with heptadecane (phase change temperature 21 °C, and the lowest indoor temperature increased by 0.86 °C with heptadecane (phase change temperature 21 °C. The annual cooling load decreased by 1.05% with dodecanol (phase change temperature 24 °C, the peak cooling load decreased by 1.30% with octadecane (phase change temperature 29 °C, and the highest indoor temperature dropped by 0.50 °C with octadecane (phase change temperature 29 °C. When the night ventilation was applied to the building HVAC system for better passive cooling performance, the annual cooling load decreased by 9.28% with dodecanol (phase change temperature 24 °C, the peak load decreased by 11.33% with octadecane (phase change temperature 29 °C, and the highest indoor temperature dropped by 0.85 °C with octadecane (phase change temperature 29 °C.

Analysis of Single-Server Queue with Phase-Type Service and Energy Harvesting

Directory of Open Access Journals (Sweden)

Sergey A. Dudin

2016-01-01

Full Text Available We propose a queueing model suitable, for example, for modelling operation of nodes of sensor networks. The sensor node senses a random field and generates packets to be transmitted to the central node. The sensor node has a battery of a finite capacity and harvests energy during its operation from outside (using solar cells, wind turbines, piezoelectric cells, etc.. We assume that, generally speaking, service (transmission of a packet consists of a random number of phases and implementation of each phase requires a unit of energy. If the battery becomes empty, transmission is failed. To reduce the probability of forced transmission termination, we suggest that the packet can be accepted for transmission only when the number of energy units is greater than or equal to some threshold. Under quite general assumptions about the pattern of the arrival processes of packets and energy, we compute the stationary distributions of the system states and the waiting time of a packet in the system and numerically analyze performance measures of the system as functions of the threshold. Validity of Little’s formula and its counterpart is verified.

Thermodynamics and phase diagrams of the plutonium-uranium, uranium-zirconium, plutonium-zirconium and plutonium-uranium-zirconium systems

International Nuclear Information System (INIS)

Agarwal, R.; Venugopal, V.

2004-05-01

Thermodynamic and phase diagram data reported in literature for the binaries, Pu-U, Pu-Zr and U-Zr , were compiled and optimised to calculate Gibbs energies of all the binary phases of these systems. Lukas program was used to carry out these optimisations, where, thermodynamic and phase diagram data of all the binary phases of a binary system were optimised simultaneously. Gibbs energy sets thus calculated were used to compare our results with the experimental and calculated phase diagram and thermodynamic data reponed in the literature. The Gibbs energies of the binary systems were then compiled together to define Pu-U-Zr ternary system. (author)

Microencapsulated Phase Change Composite Materials for Energy Efficient Buildings

Science.gov (United States)

Thiele, Alexander

This study aims to elucidate how phase change material (PCM)-composite materials can be leveraged to reduce the energy consumption of buildings and to provide cost savings to ratepayers. Phase change materials (PCMs) can store thermal energy in the form of latent heat when subjected to temperatures exceeding their melting point by undergoing a phase transition from solid to liquid state. Reversibly, PCMs can release this thermal energy when the system temperature falls below their solidification point. The goal in implementing composite PCM walls is to significantly reduce and time-shift the maximum thermal load on the building in order to reduce and smooth out the electricity demand for heating and cooling. This Ph.D. thesis aims to develop a set of thermal design methods and tools for exploring the use of PCM-composite building envelopes and for providing design rules for their practical implementation. First, detailed numerical simulations were used to show that the effective thermal conductivity of core-shell-matrix composites depended only on the volume fraction and thermal conductivity of the constituent materials. The effective medium approximation reported by Felske (2004) was in very good agreement with numerical predictions of the effective thermal conductivity. Second, a carefully validated transient thermal model was used to simulate microencapsulated PCM-composite walls subjected to diurnal or annual outdoor temperature and solar radiation flux. It was established that adding microencapsulated PCM to concrete walls both substantially reduced and delayed the thermal load on the building. Several design rules were established, most notably, (i) increasing the volume fraction of microencapsulated PCM within the wall increases the energy savings but at the potential expense of mechanical properties [1], (ii) the phase change temperature leading to the maximum energy and cost savings should equal the desired indoor temperature regardless of the climate

A Novel Coordinated Control of Renewable Energy Sources and Energy Storage System in Islanded Microgrid

DEFF Research Database (Denmark)

Gui, Yonghao; Li, Mingshen; Guerrero, Josep M.

2018-01-01

A novel coordinated control for energy storage system (ESS) and renewable energy source (RES) units is proposed in islanded AC microgrids without a phase-locked loop system. We use a proportional-resonant control technique for the ESS, which fixes the voltage and frequency of the microgrid...

A Survey of Phase Change Memory Systems

Institute of Scientific and Technical Information of China (English)

夏飞; 蒋德钧; 熊劲; 孙凝晖

2015-01-01

As the scaling of applications increases, the demand of main memory capacity increases in order to serve large working set. It is difficult for DRAM (dynamic random access memory) based memory system to satisfy the memory capacity requirement due to its limited scalability and high energy consumption. Compared to DRAM, PCM (phase change memory) has better scalability, lower energy leakage, and non-volatility. PCM memory systems have become a hot topic of academic and industrial research. However, PCM technology has the following three drawbacks: long write latency, limited write endurance, and high write energy, which raises challenges to its adoption in practice. This paper surveys architectural research work to optimize PCM memory systems. First, this paper introduces the background of PCM. Then, it surveys research efforts on PCM memory systems in performance optimization, lifetime improving, and energy saving in detail, respectively. This paper also compares and summarizes these techniques from multiple dimensions. Finally, it concludes these optimization techniques and discusses possible research directions of PCM memory systems in future.

Negative heat capacity at phase-separation in macroscopic systems

OpenAIRE

Gross, D. H. E.

2005-01-01

Systems with long-range as well with short-range interactions should necessarily have a convex entropy S(E) at proper phase transitions of first order, i.e. when a separation of phases occurs. Here the microcanonical heat capacity c(E)= -\\frac{(\\partial S/\\partial E)^2}{\\partial^2S/\\partial E^2} is negative. This should be observable even in macroscopic systems when energy fluctuations with the surrounding world can be sufficiently suppressed.

Brayton Isotope Power System. Phase I. (Ground demonstration system) Configuration Control Document (CCD)

International Nuclear Information System (INIS)

1976-01-01

The configuration control document (CCD) defines the BIPS-GDS configuration. The GDS configuration is similar to a conceptual flight system design, referred to as the BIPS-FS, which is discussed in App. I. The BIPS is being developed by ERDA as a 500 to 2000 W(e), 7-y life, space power system utilizing a closed Brayton cycle gas turbine engine to convert thermal energy (from an isotope heat source) to electrical energy at a net efficiency exceeding 25 percent. The CCD relates to Phase I of an ERDA Program to qualify a dynamic system for launch in the early 1980's. Phase I is a 35-month effort to provide an FS conceptual design and GDS design, fabrication, and test. The baseline is a 7-year life, 450-pound, 4800 W(t), 1300 W(e) system which will use two multihundred watt (MHW) isotope heat sources being developed

A portable solar-powered air-cooling system based on phase-change materials for a vehicle cabin

International Nuclear Information System (INIS)

Qi, Lingfei; Pan, Hongye; Zhu, Xin; Zhang, Xingtian; Salman, Waleed; Zhang, Zutao; Li, Li; Zhu, Miankuan; Yuan, Yanping; Xiang, Bo

2017-01-01

Graphical abstract: This paper proposed a portable solar-powered air cooling system for a vehicle cabin based on Phase-change Materials. The cooling system contains three main parts: a solar-energy collection module, an energy-storage module and a phase-change cooling module. The operating principle can be described as follows. For energy input, the solar-energy-collection module harvests solar energy and converts it to electricity. The power-storage module stores the electrical energy in the supercapacitor to power the electrical equipment, mainly the air pump (AP) and water pump (WP) of the phase-change cooling module. Finally, the phase-change cooling module provides cold air for the vehicle cabin to create a comfortable vehicle interior in a hot summer. The proposed system is demonstrated through thermal simulations, which show the long-duration cooling effect of the system. Temperature drops of were obtained in field tests, predicting that the proposed cooling system is beneficial and practical for cooling vehicle cabins. - Highlights: • A novel portable air cooling system based on PCMs is presented. • Solar energy was adopted to power the proposed air cooling system. • This proposed system is used for cooling vehicle cabins exposed to the sun. • Experimental results show that the proposed system has a good cooling effect. - Abstract: In summer, the temperature is very high inside vehicles parked under the hot sun. This causes consuming more fossil energy to power the air conditioner and generation of harmful gases. There is currently no effective method to address this problem in an energy-saving and environmentally friendly manner. In this paper, a novel solar-powered air-cooling system for vehicle cabins is proposed based on Phase-change Materials (PCMs); the system prevents the temperature inside a vehicle cabin from rising too high when the vehicle is parked outdoor exposure to the sun. The proposed system consists of three main parts: a solar-energy

Swinging control of two-pendulum system under energy constraints

NARCIS (Netherlands)

Ananyevskiy, M.S.; Fradkov, A.L.; Nijmeijer, H.; Leonov, G.; Nijmeijer, H.; Pogromsky, A.; Fradkov, A.

2009-01-01

A method for control of mechanical systems under phase constraints, applicable to energy control of Hamiltonian systems is proposed. The constrained energy control problem for two pendulums by a single control action is studied both analytically and numerically. It is shown that for a proper choice

Energy-efficient three-phase bidirectional converter for grid-connected storage applications

International Nuclear Information System (INIS)

Colmenar-Santos, Antonio; Linares-Mena, Ana-Rosa; Velázquez, Jesús Fernández; Borge-Diez, David

2016-01-01

Highlights: • Storage control system developed based on AC DC three phase bidirectional converter. • Bidirectional AC DC converter for storage integration into distribution grids. • Efficiencies over 98% for values over 30% of the bidirectional converter rated power. • Sensitivity analysis of the parameters set by the transmission system operator. • Low-cost option for control and integration of new grid-connected storage systems. - Abstract: Grid connected energy storage systems are expected to play an essential role in the development of Smart Grids, providing, among other benefits, ancillary services to power grids. It is therefore crucial to design and develop control and conversion systems that represent the key instrument where intelligence for decision-making is applied, in order to validate and ensure its optimal operation as part and parcel of the electrical system. The present research describes the design and development of a battery energy storage system based on an AC-DC three-phase bidirectional converter capable of operating either in charge mode to store electrical energy, or in discharge mode to supply load demands. The design is modelled with MATLAB® Simulink® environment in order to evaluate the performance during load variations. Moreover, the assessment is complemented by a global sensitivity analysis for variations in the operating parameters set by the transmission system operator. The effectiveness of the simulation is confirmed by implementing the system and carrying out grid connection tests, obtaining efficiencies over 98% for values over the 30% of the bidirectional converter rated power.

Computer-aided design model for anaerobic-phased-solids digester system

Energy Technology Data Exchange (ETDEWEB)

Zhang, Z.; Zhang, R. [University of California, Davis, CA (United States); Tiangco, V. [California Energy Commission, Sacramento, CA (United States)

1999-07-01

The anaerobic-phased-solids (APS) digester system is a newly developed anaerobic digestion system for converting solid wastes, such as crop residues and food wastes, into biogas for power and heat generation. A computer-aided engineering design model has been developed to design the APS-digester system and study the heat transfer from the reactors and energy production of the system. Simulation results of a case study are presented by using the model to predict the heating energy requirement and biogas energy production for anaerobic digestion of garlic waste. The important factors, such as environmental conditions, insulation properties, and characteristics of the wastes, on net energy production are also investigated. (author)

Heat-pump-centered integrated community energy systems: system development summary

Energy Technology Data Exchange (ETDEWEB)

Calm, J.M.

1980-02-01

An introduction to district heating systems employing heat pumps to enable use of low-temperature energy sources is presented. These systems operate as thermal utilities to provide space heating and may also supply space cooling, service-water heating, and other thermal services. Otherwise-wasted heat from industrial and commercial processes, natural sources including solar and geothermal heat, and heat stored on an annual cycle from summer cooling may be effectively utilized by the systems described. These sources are abundant, and their use would conserve scarce resources and reduce adverse environmental impacts. More than one-quarter of the energy consumed in the United States is used to heat and cool buildings and to heat service water. Natural gas and oil provide approximately 83% of this energy. The systems described show potential to reduce net energy consumption for these services by 20 to 50% and to allow fuel substitution with less-scarce resources not practical in smaller, individual-building systems. Seven studies performed for the system development phase of the Department of Energy's Heat-Pump-Centered Integrated Community Energy Systems Project and to related studies are summarized. A concluding chapter tabulates data from these separately published studies.

Phases, phase equilibria, and phase rules in low-dimensional systems

International Nuclear Information System (INIS)

Frolov, T.; Mishin, Y.

2015-01-01

We present a unified approach to thermodynamic description of one, two, and three dimensional phases and phase transformations among them. The approach is based on a rigorous definition of a phase applicable to thermodynamic systems of any dimensionality. Within this approach, the same thermodynamic formalism can be applied for the description of phase transformations in bulk systems, interfaces, and line defects separating interface phases. For both lines and interfaces, we rigorously derive an adsorption equation, the phase coexistence equations, and other thermodynamic relations expressed in terms of generalized line and interface excess quantities. As a generalization of the Gibbs phase rule for bulk phases, we derive phase rules for lines and interfaces and predict the maximum number of phases than may coexist in systems of the respective dimensionality

A High Energy and High Efficiency Spectral Shaping Single Frequency Fiber Laser, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — This SBIR phase II project proposes a single frequency high energy fiber laser system for coherent Lidar systems for remote sensing. Current state-of-art...

Heat of fusion storage systems for combined solar systems in low energy buildings

DEFF Research Database (Denmark)

Schultz, Jørgen Munthe; Furbo, Simon

2004-01-01

Solar heating systems for combined domestic hot water and space heating has a large potential especially in low energy houses where it is possible to take full advantage of low temperature heating systems. If a building integrated heating system is used – e.g. floor heating - the supply temperature...... from solid to liquid form (Fig. 1). Keeping the temperature as low as possible is an efficient way to reduce the heat loss from the storage. Furthermore, the PCM storage might be smaller than the equivalent water storage as more energy can be stored per volume. If the PCM further has the possibility...... systems through further improvement of water based storages and in parallel to investigate the potential of using storage designs with phase change materials, PCM. The advantage of phase change materials is that large amounts of energy can be stored without temperature increase when the material is going...

Experimental analysis of a low cost phase change material emulsion for its use as thermal storage system

International Nuclear Information System (INIS)

Delgado, Mónica; Lázaro, Ana; Mazo, Javier; Peñalosa, Conchita; Dolado, Pablo; Zalba, Belén

2015-01-01

Highlights: • A low cost PCM emulsion has been analyzed as thermal energy storage system. • Its thermophysical and rheological properties have been determined. • The system shows advantages in terms of energy density and heat transfer rate. • The PCM emulsion system has been compared to other thermal energy storage systems. - Abstract: A 46 l commercial tank with a helical coil heat exchanger and containing a low cost phase change material emulsion has been experimentally analyzed as a thermal energy storage system in terms of volumetric energy density and heat transfer rate, for its subsequent comparison with other thermal energy storage systems. This phase change material emulsion shows a phase change temperature range between 30 and 50 °C, its solids content is about 60% with an average particle size of 1 μm. The low cost phase change material emulsion shows a thermal storage capacity by mass 50% higher than water and an increase in viscosity up to 2–5 orders of magnitude. The results have shown that the global heat transfer coefficient of the phase change material emulsion tank is around 2–6 times higher than for conventional latent systems previously analyzed in literature, although 5 times lower than if it contains water. The phase change material emulsion tank presents an energy density 34% higher than the water tank, which makes it a promising solution. Measures to improve its performance are also studied in this work.

Development and characterization of a solar-hydrogen energy system

International Nuclear Information System (INIS)

Sebastian, P.J.; Vejar, S.; Gonzalez, E.; Perez, M.; Gamboa, S.A.

2009-01-01

'Full text': The details of the development of a PV-hydrogen hybrid energy system are presented. An arrangement of photovoltaic modules (125 W/module) was established to provide 9 kW installed power in a three-phase configuration at 127 Vrms/phase. A 5 kW fuel cell system (hydrogen/oxygen) operates as a dynamic backup of the photovoltaic system. The autonomous operation of the hybrid power system implies the production of hydrogen by electrolysis. The hydrogen is produced by water electrolysis using an electrolyzer of 1 kW of power. The electrical energy used to produce hydrogen is supplied from solar panels by using 1 kW of photovoltaic modules. The photovoltaic modules are installed in a sun-tracker arrangement for increasing the energy conversion efficiency. The hydrogen is stored in solar to electric commercial metal hydride based containers and supplied to the fuel cell. The hybrid system is monitored by internet, and some dynamic characteristics such as demanding power, energy and power factor could be analyzed independently from the system. Some energy saving recommendations have been implemented as a pilot program at CIE-UNAM to improve the efficient use of clean energy in normal operating conditions in offices and laboratories. (author)

Dynamics of energy storage in phase change drywall systems

Energy Technology Data Exchange (ETDEWEB)

Darkwa, K.; Kim, J.-S. [Nottingham Trent University (United Kingdom). School of the Built Environment

2005-07-01

Experimental evaluations of manufactured samples of laminated and randomly mixed phase change material (PCM) drywalls have been carried out and compared with numerical results. The analysis showed that the laminated PCM drywall performed thermally better. Even though there was a maximum 3% deviation of the average experimental result from the numerical values, the laminated PCM board achieved about 55% of the phase change process as against 48% for the randomly distributed drywall sample. The laminated board sample also released about 27% more latent heat than the randomly distributed type at the optimum time of 90 min thus validating previous simulation study. Given the experimental conditions and assumptions the experiment has proved that it is feasible to develop the laminated PCM technique for enhancing and minimising multi-dimensional heat transfers in drywall systems. Further practical developments are however encouraged to improve the overall level of heat transfer. (author)

Zero-voltage ride-through capability of single-phase grid-connected photovoltaic systems

DEFF Research Database (Denmark)

Zhang, Zhen; Yang, Yongheng; Ma, Ruiqing

2017-01-01

Distributed renewable energy systems play an increasing role in today’s energy paradigm. Thus, intensive research activities have been centered on improving the performance of renewable energy systems, including photovoltaic (PV) systems, which should be of multiple-functionality. That is, the PV...... systems should be more intelligent in the consideration of grid stability, reliability, and fault protection. Therefore, in this paper, the performance of single-phase grid-connected PV systems under an extreme grid fault (i.e., when the grid voltage dips to zero) is explored. It has been revealed...... that combining a fast and accurate synchronization mechanism with appropriate control strategies for the zero-voltage ride-through (ZVRT) operation is mandatory. Accordingly, the representative synchronization techniques (i.e., the phase-locked loop (PLL) methods) in the ZVRT operation are compared in terms...

A High Energy and High Efficiency Spectral Shaping Single Frequency Fiber Laser, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — This SBIR phase I project proposes a tunable single frequency high energy fiber laser system for coherent Lidar systems for remote sensing. Current state-of-art...

Heavy quark free energies for three quark systems at finite temperature

International Nuclear Information System (INIS)

Huebner, Kay; Karsch, Frithjof; Kaczmarek, Olaf; Vogt, Oliver

2008-01-01

We study the free energy of static three quark systems in singlet, octet, decuplet, and average color channels in the quenched approximation and in 2-flavor QCD at finite temperature. We show that in the high temperature phase singlet and decuplet free energies of three quark systems are well described by the sum of the free energies of three diquark systems plus self-energy contributions of the three quarks. In the confining low temperature phase we find evidence for a Y-shaped flux tube in SU(3) pure gauge theory, which is less evident in 2-flavor QCD due to the onset of string breaking. We also compare the short distance behavior of octet and decuplet free energies to the free energies of single static quarks in the corresponding color representations.

Thermodynamic Calculations of Ternary Polyalcohol and Amine Phase Diagrams for Thermal Energy Storage Materials

Science.gov (United States)

Shi, Renhai

Organic polyalcohol and amine globular molecular crystal materials as phase change materials (PCMs) such as Pentaglycerine (PG-(CH3)C(CH 2OH)3), Tris(hydroxymethyl)aminomethane (TRIS-(NH2)C(CH 2OH)3), 2-amino-2methyl-1,3-propanediol (AMPL-(NH2)(CH3)C(CH2OH)2), and neopentylglycol (NPG-(CH3)2C(CH2OH) 2) can be considered to be potential candidates for thermal energy storage (TES) applications such as waste heat recovery, solar energy utilization, energy saving in buildings, and electronic device management during heating or cooling process in which the latent heat and sensible heat can be reversibly stored or released through solid state phase transitions over a range of temperatures. In order to understand the polymorphism of phase transition of these organic materials and provide more choice of materials design for TES, binary systems have been studied to lower the temperature of solid-state phase transition for the specific application. To our best knowledge, the study of ternary systems in these organic materials is limited. Based on this motivation, four ternary systems of PG-TRIS-AMPL, PG-TRIS-NPG, PG-AMPL-NPG, and TRIS-AMPL-NPG are proposed in this dissertation. Firstly, thermodynamic assessment with CALPHAD method is used to construct the Gibbs energy functions into thermodynamic database for these four materials based on available experimental results from X-Ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC). The phase stability and thermodynamic characteristics of these four materials calculated from present thermodynamic database with CALPHAD method can match well the present experimental results from XRD and DSC. Secondly, related six binary phase diagrams of PG-TRIS, PG-AMPL, PG-NPG, TRIS-AMPL, TRIS-NPG, and AMPL-NPG are optimized with CALPHAD method in Thermo-Calc software based on available experimental results, in which the substitutional model is used and excess Gibbs energy is expressed with Redlich-Kister formalism. The

Phase holonomy, zero-point energy cancellation and supersymmetric quantum mechanics

International Nuclear Information System (INIS)

Iida, Shinji; Kuratsuji, Hiroshi

1987-01-01

We show that the zero-point energy of bosons is cancelled out by the phase holonomy which is induced by the adiabatic deformation of a boson system coupled with a fermion. This mechanism results in a supersymmetric quantum mechanics as a special case and presents a possible dynamical origin of supersymmetry. (orig.)

Analysis of free-surface flows through energy considerations: Single-phase versus two-phase modeling.

Science.gov (United States)

Marrone, Salvatore; Colagrossi, Andrea; Di Mascio, Andrea; Le Touzé, David

2016-05-01

The study of energetic free-surface flows is challenging because of the large range of interface scales involved due to multiple fragmentations and reconnections of the air-water interface with the formation of drops and bubbles. Because of their complexity the investigation of such phenomena through numerical simulation largely increased during recent years. Actually, in the last decades different numerical models have been developed to study these flows, especially in the context of particle methods. In the latter a single-phase approximation is usually adopted to reduce the computational costs and the model complexity. While it is well known that the role of air largely affects the local flow evolution, it is still not clear whether this single-phase approximation is able to predict global flow features like the evolution of the global mechanical energy dissipation. The present work is dedicated to this topic through the study of a selected problem simulated with both single-phase and two-phase models. It is shown that, interestingly, even though flow evolutions are different, energy evolutions can be similar when including or not the presence of air. This is remarkable since, in the problem considered, with the two-phase model about half of the energy is lost in the air phase while in the one-phase model the energy is mainly dissipated by cavity collapses.

Organic Rankine Kilowatt Isotope Power System. Final phase I report

International Nuclear Information System (INIS)

1978-01-01

On 1 August 1975 under Department of Energy Contract EN-77-C-02-4299, Sundstrand Energy Systems commenced development of a Kilowatt Isotope Power System (KIPS) directed toward satisfying the higher power requirements of satellites of the 1980s and beyond. The KIPS is a 238 PuO 2 fueled organic Rankine cycle turbine power system which will provide design output power in the range of 500 to 2000 W/sub (e)/ with a minimum of system changes. The principal objectives of the Phase 1 development effort were to: conceptually design a flight system; design a Ground Demonstration System (GDS) that is prototypic of the flight system in order to prove the feasibility of the flight system design; fabricate and assemble the GDS; and performance and endurance test the GDS using electric heaters in lieu of the isotope heat source. Results of the work performed under the Phase 1 contract to 1 July 1978 are presented

Unconventional phases in quantum spin and pseudospin systems in two dimensional and three dimensional lattices

Science.gov (United States)

Xu, Cenke

Several examples of quantum spin systems and pseudo spin systems have been studied, and unconventional states of matters and phase transitions have been realized in all these systems under consideration. In the p +/- ip superconductor Josephson lattice and the p--band cold atomic system trapped in optical lattices, novel phases which behave similarly to 1+1 dimensional systems are realized, despite the fact that the real physical systems are in two or three dimensional spaces. For instance, by employing a spin-wave analysis together with a new duality transformation, we establish the existence and stability of a novel gapless "critical phase", which we refer to as a "bond algebraic liquid". This novel critical phase is analogous to the 1+1 dimensional algebraic boson liquid phase. The reason for the novel physics is that there is a quasilocal gauge symmetry in the effective low energy Hamiltonian. In a spin-1 system on the kagome lattice, and a hard-core boson system on the honeycomb lattice, the low energy physics is controlled by two components of compact U(1) gauge symmetries that emerge at low energy. Making use of the confinement nature of the 2+1 dimensional compact gauge theories and the powerful duality between gauge theories and height field theories, the crystalline phase diagrams are studied for both systems, and the transitions to other phases are also considered. These phase diagrams might be accessible in strongly correlated materials, or atomic systems in optical lattices. A novel quantum ground state of matter is realized in a bosonic model on three dimensional fcc lattice with emergent low energy excitations. The novel phase obtained is a stable gapless boson liquid phase, with algebraic boson density correlations. The stability of this phase is protected against the instanton effect and superfluidity by self-duality and large gauge symmetries on both sides of the duality. The gapless collective excitations of this phase closely resemble the

Phase diagram of a modified Lennard-Jones system

International Nuclear Information System (INIS)

Sakagami, Takahiro; Fuchizaki, Kazuhiro

2010-01-01

The well-known Lennard-Jones potential is modified in such a way that it smoothly vanishes at a certain distance. A system whose interparticle interaction is given by such a potential is referred to as a modified Lennard-Jones system, and is served as a standard system describing simple solids and fluids. A phase diagram is determined based on the free energies obtained through thermodynamic integration.

Thermal energy storage with phase change materials (PCMs) for the improvement of the energy performance of buildings

Science.gov (United States)

Soares, Nelson

The improvement of the energy efficiency of buildings during their operational phase is an active area of research. The markets are looking for new technologies, namely new thermal energy storage (TES) systems, which can be used to reduce buildings' dependency on fossil fuels, to make use of renewable energy sources and to contribute to match energy supply and demand efficiently. The main goals of this thesis are: (i) to evaluate the heat transfer with solid-liquid phase-change through small TES units filled with phase-change materials (PCMs), providing experimental data to be used in the design of new TES systems for buildings and in the validation of numerical models, and (ii) to provide some guidelines for the incorporation of PCM-drywalls in buildings aiming to reduce the energy demand for heating and cooling by making use of the latent heat from the phase-change processes of PCMs. The first part of this thesis refers to the experimental study of the heat transfer through a vertical stack of metallic rectangular cavities filled with different PCMs (a microencapsulated and a free-form PCM). The research carried out aims: (i) to analyze the melting and solidification processes of the PCM within the enclosures, (ii) to evaluate the influence of the aspect ratio of the cavities on the heat transfer and (iii) to discuss which type of PCM is better for specific cases. As a result, a big amount of experimental data for benchmarking and validation of numerical models is made available to the scientific community. Moreover, the results allow discussing which arrangement of the TES unit is better for specific applications considering the thermal regulation effect during charging, the influence of subcooling during discharging, and the influence of natural convection during both processes. It is shown that the effect of natural convection in the free-form PCM must be considered in any simulation to better describe the charging process. During discharging, subcooling must

Novel low harmonics 3-phase rectifiers for efficient motor systems; Novel low harmonics 3-phase rectifiers for efficient motor systems. Konzeptstudie - Schlussbericht

Energy Technology Data Exchange (ETDEWEB)

Pietkiewicz, A.; Melly, S.; Tucker, A.; Haeberle, N. [Schaffner EMV AG, Luterbach (Switzerland); Biner, H.-P. [Haute Ecole Specialisee de Suisse occidentale, HES-SO Valais, Sion (Switzerland)

2010-07-15

This final report for the Swiss Federal Office of Energy (SFOE) presents the results of a concept study made concerning novel low harmonics 3-phase rectifiers for efficient motor systems. The harmonic distortions which are produced by these systems are discussed and ways of minimising them are examined. The authors discuss novel, passive, multi-pulse current splitters that are considered to be cost efficient, compact and highly-reliable harmonics mitigation concepts for three-phase loads. According to the authors, functional prototypes for a nominal load of 4 kW proved, in laboratory tests, the outstanding properties of multi-pulse current splitters with respect to harmonics cancellation and robustness against voltage asymmetry. The design process, prototype construction and application tests are discussed, as are energy-saving potentials and marketing aspects.

Proceedings of the 13th Energy System and Economy Conference; Dai 13 kai energy system keizai conference koen ronbunshu

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-01-30

The Energy System and Economy Conference was held in Tokyo on January 30 and 31, 1997, including 80 papers made public, keynote speeches having a theme of the international situation in the climate change issue and the Japanese condition, and panel discussions. In the special session on the global environmental problem, speeches were given on CO2 emission/reduction, CO2 recovery/fixation, environmental policy, comprehensive analyses, etc. In the electric power economy section, reports were made on effects of load characteristics of the power system on the effectiveness of power supply, the free electric power market and DSM (demand-side management), etc. As to the energy system, reported were a study on increasing efficiency of the hydrogen use regional heat supply system, samples of the hydrogen energy system for local core cities, etc. Relating to the energy technology, a paper on a proposal of solid phase heat engines using shape memory alloys and others were read. Papers were more added on urban and commercial/residential energy, natural energy, traffic, energy economy, etc.

Enthalpy of phase transition and prediction of phase Equilibria in systems of glycols and glycol ethers

OpenAIRE

Esina, Zoya; Miroshnikov, Aleksandr; Korchuganova, Margarita

2014-01-01

The PCEAS model was used to study the liquid-solid and liquid-vapor phase transitions at constant pressure in systems containing glycols and glycol ethers. This method is based on minimizing the excess Gibbs energy over the solvation parameter, which takes into account the processes of association of molecules in various phases. To compute the diagrams, the data on enthalpy and phase transition temperatures of pure components are required, while the information about the interactions in the b...

DOE Heat Pump Centered Integrated Community Energy Systems Project

Energy Technology Data Exchange (ETDEWEB)

Calm, J. M.

1979-01-01

The Heat Pump Centered Integrated Community Energy Systems (HP-ICES) Project is a multiphase undertaking seeking to demonstrate one or more operational HP-ICES by the end of 1983. The seven phases include System Development, Demonstration Design, Design Completion, HP-ICES Construction, Operation and Data Acquisition, HP-ICES Evaluation, and Upgraded Continuation. This project is sponsored by the Community Systems Branch, Office of Buildings and Community Systems, Assistant Secretary for Conservation and Solar Applicaions, U.S. Department of Energy (DOE). It is part of the Community Systems Program and is managed by the Energy and Environmental Systems Division of Argonne Natinal Laboratory.

A compact seven switches topology and reduced DC-link capacitor size for single-phase stand-alone PV system with hybrid energy storages

DEFF Research Database (Denmark)

Liu, Xiong; Wang, Peng; Loh, Poh Chiang

2011-01-01

Single-phase stand-alone PV system is suitable for household applications in remote area. Hybrid battery/ultra-capacitor energy storage can reduce charge and discharge cycles and avoid deep discharges of battery. This paper proposes a compact seven switches structure for stand-alone PV system......, which otherwise needs nine switches configuration, inclusive of one switch for boost converter, four switches for single-phase inverter and four switches for two DC/DC converters of battery and ultra-capacitor. It is well-known that a bulky DC-link capacitor is always required to absorb second......-order harmonic current caused by single-phase inverter. In the proposed compact topology, a small size DC-link capacitor can achieve the same function through charging/discharging control of ultra-capacitor to mitigate second-order ripple current. Simulation results are provided to validate the effectiveness...

Experiments on hydraulically-compensated Compressed Air Energy Storage (CAES) system using large-diameter vertical pipe two-phase flow test facility: test facility and test procedure

International Nuclear Information System (INIS)

Ohtsu, Iwao; Murata, Hideo; Kukita, Yutaka; Kumamaru, Hiroshige.

1996-07-01

JAERI, the University of Tokyo, the Central Research Institute of Electric Power Industry and Shimizu Corporation jointing performed and experimental study on two-phase flow in the hydraulically-compensated Compressed Air Energy Storage (CAES) system with a large-diameter vertical pipe two-phase flow test facility from 1993 to 1995. A hydraulically-compensated CAES system is a proposed, conceptual energy storage system where energy is stored in the form of compressed air in an underground cavern which is sealed by a deep (several hundred meters) water shaft. The shaft water head maintains a constant pressure in the cavern, of several mega Pascals, even during loading or unloading of the cavern with air. The dissolved air in the water, however, may create voids in the shaft when the water rises through the shaft during the loading, being forced by the air flow into the cavern. The voids may reduce the effective head of the shaft, and thus the seal may fail, if significant bubbling should occur in the shaft. This bubbling phenomenon (termed 'Champaign effect') and potential failure of the water seal ('blowout') are simulated in a scaled-height, scaled-diameter facility. Carbon dioxide is used to simulate high solubility of air in the full-height, full-pressure system. This report describes the expected and potential two-phase flow phenomena in a hydraulically-compensated CAES system, the test facility and the test procedure, a method to estimate quantities which are not directly measured by using measured quantities and hydrodynamic basic equations, and desirable additional instrumentation. (author)

Developing an energy design tool: Phase 1 report

Energy Technology Data Exchange (ETDEWEB)

Heidell, J.A.; Deringer, J.D.

1987-02-01

This report documents the planning phase of a proposed four-phase project for creating computer software to provide energy expertise in a manageable form to architects and engineers - thereby decreasing energy use in new buildings. The government sponsored software would be integrated with commercially developed software for use in the design of buildings. The result would be an integrated software package to aid the designer in the building design process and to provide expert insight into the energy related implications of a proposed design.

Solar central receiver hybrid power system. Phase I study

Energy Technology Data Exchange (ETDEWEB)

None

1978-11-01

A management plan is presented for implementation during the Solar Central Receiver Hybrid Power System - Phase I study project. The project plan and the management controls that will be used to assure technically adequate, timely and cost effective performance of the work required to prepare the designated end products are described. Bechtel in-house controls and those to be used in directing the subcontractors are described. Phase I of the project consists of tradeoff studies, parametric analyses, and engineering studies leading to conceptual definition and evaluation of a commercial hybrid power system that has the potential for supplying economically competitive electric power to a utility grid in the 1985-1990 time frame. The scope also includes the preparation of a development plan for the resolution of technical uncertainties and the preparation of plans and a proposal for Phase II of the program. The technical approach will be based on a central receiver solar energy collection scheme which supplies thermal energy to a combined cycle, generating system, consisting of a gas turbine cycle combined with a steam bottoming cycle by means of a heat recovery steam generator.

Using reweighting and free energy surface interpolation to predict solid-solid phase diagrams

Science.gov (United States)

Schieber, Natalie P.; Dybeck, Eric C.; Shirts, Michael R.

2018-04-01

Many physical properties of small organic molecules are dependent on the current crystal packing, or polymorph, of the material, including bioavailability of pharmaceuticals, optical properties of dyes, and charge transport properties of semiconductors. Predicting the most stable crystalline form at a given temperature and pressure requires determining the crystalline form with the lowest relative Gibbs free energy. Effective computational prediction of the most stable polymorph could save significant time and effort in the design of novel molecular crystalline solids or predict their behavior under new conditions. In this study, we introduce a new approach using multistate reweighting to address the problem of determining solid-solid phase diagrams and apply this approach to the phase diagram of solid benzene. For this approach, we perform sampling at a selection of temperature and pressure states in the region of interest. We use multistate reweighting methods to determine the reduced free energy differences between T and P states within a given polymorph and validate this phase diagram using several measures. The relative stability of the polymorphs at the sampled states can be successively interpolated from these points to create the phase diagram by combining these reduced free energy differences with a reference Gibbs free energy difference between polymorphs. The method also allows for straightforward estimation of uncertainties in the phase boundary. We also find that when properly implemented, multistate reweighting for phase diagram determination scales better with the size of the system than previously estimated.

Volume 1: Survey of Available Information in Support of the Energy-Water Bandwidth Study of Desalination Systems

Energy Technology Data Exchange (ETDEWEB)

Rao, Prakash [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Aghajanzadeh, Arian [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sheaffer, Paul [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Morrow, William R. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Brueske, Sabine [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Dollinger, Caroline [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Price, Kevin [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sarker, Prateeti [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Ward, Nicholas [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Cresko, Joe [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2016-10-01

The U.S. Department of Energy (DOE) has set a goal to reduce the cost of seawater desalination systems to $0.50/ cubic meter (m³) through the development of technology pathways to reduce energy, capital, operating, soft, and system integration costs.1 In support of this goal and to evaluate the technology pathways to lower the energy and carbon intensity of desalination while also reducing the total water cost, DOE is undertaking a comprehensive study of the energy consumption and carbon dioxide (CO₂) emissions for desalination technologies and systems. This study is being undertaken in two phases. Phase 1, Survey of Available Information in Support of the Energy-Water Bandwidth Study of Desalination Systems, collected the background information that will underpin Phase 2, the Energy Water Bandwidth Study for Desalination Systems. This report (Volume 1) summarizes the results from Phase 1. The results from Phase 2 will be summarized in Volume 2: Energy Water Bandwidth Study for Desalination Systems (Volume 2). The analysis effort for Phase 2 will utilize similar methods as other industry-specific Energy Bandwidth Studies developed by DOE,2 which has provided a framework to evaluate and compare energy savings potentials within and across manufacturing sectors at the macroscale. Volume 2 will assess the current state of desalination energy intensity and reduction potential through the use of advanced and emerging technologies. For the purpose of both phases of study, energy intensity is defined as the amount of energy required per unit of product water output (for example, kilowatt-hours per cubic meter of water produced). These studies will expand the scope of previous sectorial bandwidth studies by also evaluating CO₂ intensity and reduction opportunities and informing a techno-economic analysis of desalination systems. Volume 2 is expected to be completed in 2017.

Phase Offsets and the Energy Budgets of Hot Jupiters

Science.gov (United States)

Schwartz, Joel C.; Kashner, Zane; Jovmir, Diana; Cowan, Nicolas B.

2017-12-01

Thermal phase curves of short-period planets on circular orbits provide joint constraints on the fraction of incoming energy that is reflected (Bond albedo) and the fraction of absorbed energy radiated by the night hemisphere (heat recirculation efficiency). Many empirical studies of hot Jupiters have implicitly assumed that the dayside is the hottest hemisphere and the nightside is the coldest hemisphere. For a given eclipse depth and phase amplitude, an orbital lag between a planet’s peak brightness and its eclipse—a phase offset—implies that planet’s nightside emits greater flux. To quantify how phase offsets impact the energy budgets of short-period planets, we compile all infrared observations of the nine planets with multi-band eclipse depths and phase curves. Accounting for phase offsets shifts planets to lower Bond albedo and greater day-night heat transport, usually by ≲1σ. For WASP-12b, the published phase variations have been analyzed in two different ways, and the inferred energy budget depends sensitively on which analysis one adopts. Our fiducial scenario supports a Bond albedo of {0.27}-0.13+0.12, significantly higher than the published optical geometric albedo, and a recirculation efficiency of {0.03}-0.02+0.07, following the trend of larger day-night temperature contrast with greater stellar irradiation. If instead we adopt the alternative analysis, then WASP-12b has a Bond albedo consistent with zero and a much higher recirculation efficiency. To definitively determine the energy budget of WASP-12b, new observational analyses will be necessary.

Innovative Application of Maintenance-Free Phase-Change Thermal Energy Storage for Dish-Engine Solar Power Generation

Energy Technology Data Exchange (ETDEWEB)

Qui, Songgang [Temple University; Galbraith, Ross [Infinia

2013-01-23

This final report summarizes the final results of the Phase II Innovative Application of Maintenance-Free Phase-Change Thermal Energy Storage for Dish-Engine Solar Power Generation project being performed by Infinia Corporation for the U.S. Department of Energy under contract DE-FC36-08GO18157 during the project period of September 1, 2009 - August 30, 2012. The primary objective of this project is to demonstrate the practicality of integrating thermal energy storage (TES) modules, using a suitable thermal salt phase-change material (PCM) as its medium, with a dish/Stirling engine; enabling the system to operate during cloud transients and to provide dispatchable power for 4 to 6 hours after sunset. A laboratory prototype designed to provide 3 kW-h of net electrical output was constructed and tested at Infinia's Ogden Headquarters. In the course of the testing, it was determined that the system's heat pipe network - used to transfer incoming heat from the solar receiver to both the Stirling generator heater head and to the phase change salt - did not perform to expectations. The heat pipes had limited capacity to deliver sufficient heat energy to the generator and salt mass while in a charging mode, which was highly dependent on the orientation of the device (vertical versus horizontal). In addition, the TES system was only able to extract about 30 to 40% of the expected amount of energy from the phase change salt once it was fully molten. However, the use of heat pipes to transfer heat energy to and from a thermal energy storage medium is a key technical innovation, and the project team feels that the limitations of the current device could be greatly improved with further development. A detailed study of manufacturing costs using the prototype TES module as a basis indicates that meeting DOE LCOE goals with this hardware requires significant efforts. Improvement can be made by implementing aggressive cost-down initiatives in design and materials

Supersymmetric quantum mechanics, phase equivalence, and low energy scattering anomalies

International Nuclear Information System (INIS)

Amado, R.D.; Cannata, F.; Dedonder, J.P.

1991-01-01

Supersymmetric quantum mechanics links two Hamiltonians with the same scattering (phase equivalence) but different number of bound states. We examine the Green's functions for these Hamiltonians as a prelude to embedding the two-body dynamics in a many-body system. We study the effect of the elimination of a two-body bound state near zero energy for the Efimov effect and Beg's theorem

Energy Economic Data Base Program (EEDB). Phase V update (1982) report

International Nuclear Information System (INIS)

1983-07-01

This Phase V Update of the Energy Economic Data Base (EEDB) is the latest in a series of cost studies dating back to the late 1960's that have provided the Department of Energy and its predecessor agencies with consistent data on the capital costs of reactor systems of current interest to the Nuclear Energy program and on the comparative costs of large fossil-fueled systems. This report summarizes the detailed data from the EEDB at an intermediate level and summarizes what has been learned from this year's Update. This report also contains fuel cycle and O and M cost data, but the emphasis of the program and the report is on capital costs. The DOE Office of Nuclear Energy summarizes the capital cost data as well as additional fuel cycle and O and M cost data in a separate report, Nuclear Energy Cost Data Base - A Reference Data Base for Nuclear and Coal-Fired Powerplant Power Generation Cost Analysis, DOE/NE-0044

Assessment of Energy Storage Alternatives in the Puget Sound Energy System

Energy Technology Data Exchange (ETDEWEB)

Balducci, Patrick J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Jin, Chunlian [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wu, Di [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Leslie, Patrick [Puget Sound Energy, Bellevue, WA (United States); Daitch, Charles [Puget Sound Energy, Bellevue, WA (United States); Marshall, A. [Primus Power, Hayward, CA (United States)

2013-12-01

As part of an ongoing study co-funded by the Bonneville Power Administration, under its Technology Innovation Grant Program, and the U.S. Department of Energy, the Pacific Northwest National Laboratory (PNNL) has developed an approach and modeling tool for assessing the net benefits of using energy storage located close to the customer in the distribution grid to manage demand. PNNL in collaboration with PSE and Primus Power has evaluated the net benefits of placing a zinc bromide battery system at two locations in the PSE system (Baker River / Rockport and Bainbridge Island). Energy storage can provide a number of benefits to the utility through the increased flexibility it provides to the grid system. Applications evaluated in the assessment include capacity value, balancing services, arbitrage, distribution deferral and outage mitigation. This report outlines the methodology developed for this study and Phase I results.

Multiple Energy System Analysis of Smart Energy Systems

DEFF Research Database (Denmark)

Thellufsen, Jakob Zinck

2015-01-01

thermal grids and smart gas grids, Smart Energy Systems moves the flexibility away from the fuel as is the case in current energy systems and into the system itself. However, most studies applying a Smart Energy System approach deals with analyses for either single countries or whole continents......To eliminate the use of fossil fuels in the energy sector it is necessary to transition to future 100% renewable energy systems. One approach for this radical change in our energy systems is Smart Energy Systems. With a focus on development and interaction between smart electricity grids, smart......, but it is unclear how regions, municipalities, and communities should deal with these national targets. It is necessary to be able to provide this information since Smart Energy Systems utilize energy resources and initiatives that have strong relations to local authorities and communities, such as onshore wind...

Medium-Energy Nuclear Data Library (MENDLIB): Phase 1

International Nuclear Information System (INIS)

Siciliano, E.R.; Arthur, E.D.

1987-10-01

This document describes an initial step towards the formation of a computerized on-line data library, which would contain published medium-energy experimental data, and which would serve the basic and applied needs of the medium-energy nuclear physics community. The data emphasized in this project will be from measured charged-particle and meson induced nuclear scattering and reactions; an area for which no such data base presently exists. Access to the data will be through a menu-driven program in a user-friendly environment. The project is divided into three phases: Phase 1 involves compilation of Clinton P. Anderson Meson Physics Facility (LAMPF) data from nucleon and pion induced reactions, Phase 2 includes nucleon and pion data from other medium-energy facilities, and Phase 3 includes electron, light-ion, and possibly kaon and anti-nucleon data. The initial goals, the manner in which they would be pursued, and the resources needed to implement Phase 1 (the pilot phase) are discussed in detail. Possible expansion of Phase 1 to attain the envisioned goals of Phase 2 and 3 are briefly outlined. During all stages of the project, input from the community will be sought via the various facility user groups and the American Physical Society Division of Nuclear Physics. It is proposed that the Applied Nuclear Science Group (T-2) of the Los Alamos National Laboratory oversees the development and implementation of this project, and the LAMPF VAX computers be used as the host computers for on-line access

Energy law preserving C0 finite element schemes for phase field models in two-phase flow computations

International Nuclear Information System (INIS)

Hua Jinsong; Lin Ping; Liu Chun; Wang Qi

2011-01-01

Highlights: → We study phase-field models for multi-phase flow computation. → We develop an energy-law preserving C0 FEM. → We show that the energy-law preserving method work better. → We overcome unphysical oscillation associated with the Cahn-Hilliard model. - Abstract: We use the idea in to develop the energy law preserving method and compute the diffusive interface (phase-field) models of Allen-Cahn and Cahn-Hilliard type, respectively, governing the motion of two-phase incompressible flows. We discretize these two models using a C 0 finite element in space and a modified midpoint scheme in time. To increase the stability in the pressure variable we treat the divergence free condition by a penalty formulation, under which the discrete energy law can still be derived for these diffusive interface models. Through an example we demonstrate that the energy law preserving method is beneficial for computing these multi-phase flow models. We also demonstrate that when applying the energy law preserving method to the model of Cahn-Hilliard type, un-physical interfacial oscillations may occur. We examine the source of such oscillations and a remedy is presented to eliminate the oscillations. A few two-phase incompressible flow examples are computed to show the good performance of our method.

Characterization of a high-energy in-line phase contrast tomosynthesis prototype.

Science.gov (United States)

Wu, Di; Yan, Aimin; Li, Yuhua; Wong, Molly D; Zheng, Bin; Wu, Xizeng; Liu, Hong

2015-05-01

In this research, a high-energy in-line phase contrast tomosynthesis prototype was developed and characterized through quantitative investigations and phantom studies. The prototype system consists of an x-ray source, a motorized rotation stage, and a CMOS detector with a pixel pitch of 0.05 mm. The x-ray source was operated at 120 kVp for this study, and the objects were mounted on the rotation stage 76.2 cm (R1) from the source and 114.3 cm (R2) from the detector. The large air gap between the object and detector guarantees sufficient phase-shift effects. The quantitative evaluation of this prototype included modulation transfer function and noise power spectrum measurements conducted under both projection mode and tomosynthesis mode. Phantom studies were performed including three custom designed phantoms with complex structures: a five-layer bubble wrap phantom, a fishbone phantom, and a chicken breast phantom with embedded fibrils and mass structures extracted from an ACR phantom. In-plane images of the phantoms were acquired to investigate their image qualities through observation, intensity profile plots, edge enhancement evaluations, and/or contrast-to-noise ratio calculations. In addition, the robust phase-attenuation duality (PAD)-based phase retrieval method was applied to tomosynthesis for the first time in this research. It was utilized as a preprocessing method to fully exhibit phase contrast on the angular projection before reconstruction. The resolution and noise characteristics of this high-energy in-line phase contrast tomosynthesis prototype were successfully investigated and demonstrated. The phantom studies demonstrated that this imaging prototype can successfully remove the structure overlapping in phantom projections, obtain delineate interfaces, and achieve better contrast-to-noise ratio after applying phase retrieval to the angular projections. This research successfully demonstrated a high-energy in-line phase contrast tomosynthesis

Energy barriers between metastable states in first-order quantum phase transitions

Science.gov (United States)

Wald, Sascha; Timpanaro, André M.; Cormick, Cecilia; Landi, Gabriel T.

2018-02-01

A system of neutral atoms trapped in an optical lattice and dispersively coupled to the field of an optical cavity can realize a variation of the Bose-Hubbard model with infinite-range interactions. This model exhibits a first-order quantum phase transition between a Mott insulator and a charge density wave, with spontaneous symmetry breaking between even and odd sites, as was recently observed experimentally [Landig et al., Nature (London) 532, 476 (2016), 10.1038/nature17409]. In the present paper, we approach the analysis of this transition using a variational model which allows us to establish the notion of an energy barrier separating the two phases. Using a discrete WKB method, we then show that the local tunneling of atoms between adjacent sites lowers this energy barrier and hence facilitates the transition. Within our simplified description, we are thus able to augment the phase diagram of the model with information concerning the height of the barrier separating the metastable minima from the global minimum in each phase, which is an essential aspect for the understanding of the reconfiguration dynamics induced by a quench across a quantum critical point.

Advanced Communication and Control for Distributed Energy Resource Integration: Phase 2 Scientific Report

Energy Technology Data Exchange (ETDEWEB)

BPL Global

2008-09-30

The objective of this research project is to demonstrate sensing, communication, information and control technologies to achieve a seamless integration of multivendor distributed energy resource (DER) units at aggregation levels that meet individual user requirements for facility operations (residential, commercial, industrial, manufacturing, etc.) and further serve as resource options for electric and natural gas utilities. The fully demonstrated DER aggregation system with embodiment of communication and control technologies will lead to real-time, interactive, customer-managed service networks to achieve greater customer value. Work on this Advanced Communication and Control Project (ACCP) consists of a two-phase approach for an integrated demonstration of communication and control technologies to achieve a seamless integration of DER units to reach progressive levels of aggregated power output. Phase I involved design and proof-of-design, and Phase II involves real-world demonstration of the Phase I design architecture. The scope of work for Phase II of this ACCP involves demonstrating the Phase I design architecture in large scale real-world settings while integrating with the operations of one or more electricity supplier feeder lines. The communication and control architectures for integrated demonstration shall encompass combinations of software and hardware components, including: sensors, data acquisition and communication systems, remote monitoring systems, metering (interval revenue, real-time), local and wide area networks, Web-based systems, smart controls, energy management/information systems with control and automation of building energy loads, and demand-response management with integration of real-time market pricing. For Phase II, BPL Global shall demonstrate the Phase I design for integrating and controlling the operation of more than 10 DER units, dispersed at various locations in one or more Independent System Operator (ISO) Control Areas, at

What Is Energy Systems Integration? | Energy Systems Integration Facility |

Science.gov (United States)

NREL What Is Energy Systems Integration? What Is Energy Systems Integration? Energy systems integration (ESI) is an approach to solving big energy challenges that explores ways for energy systems to Research Community NREL is a founding member of the International Institute for Energy Systems Integration

SOLGASMIX-PV, Chemical System Equilibrium of Gaseous and Condensed Phase Mixtures

International Nuclear Information System (INIS)

Besmann, T.M.

1986-01-01

1 - Description of program or function: SOLGASMIX-PV, which is based on the earlier SOLGAS and SOLGASMIX codes, calculates equilibrium relationships in complex chemical systems. Chemical equilibrium calculations involve finding the system composition, within certain constraints, which contains the minimum free energy. The constraints are the preservation of the masses of each element present and either constant pressure or volume. SOLGASMIX-PV can calculate equilibria in systems containing a gaseous phase, condensed phase solutions, and condensed phases of invariant and variable stoichiometry. Either a constant total gas volume or a constant total pressure can be assumed. Unit activities for condensed phases and ideality for solutions are assumed, although nonideal systems can be handled provided activity coefficient relationships are available. 2 - Restrictions on the complexity of the problem: The program is designed to handle a maximum of 20 elements, 99 substances, and 10 mixtures, where the gas phase is considered a mixture. Each substance is either a gas or condensed phase species, or a member of a condensed phase mixture

Matrix converter applied to energy saving for street lighting systems

OpenAIRE

Román Lumbreras, Manuel; Velasco Quesada, Guillermo; Conesa Roca, Alfons

2010-01-01

This work presents a three-phase AC-AC converter, with independent phase control, based on matrix-converter structure. This converter is applied to electrical energy saving on the public lighting systems by means of regulation and control of the voltage applied to the lamps. The developed converter represents a technological improvement with respect to the traditional systems based on an autotransformer: it reduces system cost and volume, and increases lamps lifetime.

Grid-connected integrated community energy system. Phase II, Stage 1, final report. Conceptual design, demand and fuel projections and cost analysis

Energy Technology Data Exchange (ETDEWEB)

1978-03-08

The Phase I Report, Grid ICES, presented the broad alternatives and implications for development of an energy system satisfying thermal demand with the co-generation of electric power, all predicated on the use of solid fuels. Participants of the system are the University of Minnesota, operator and primary thermal user, and Northern States Power Company, primary electrical user; with St. Mary's Hospital, Fairview Hospital, and Augsburg College as Add-on Customers for the thermal service (Option I). Included for consideration are the Options of (II) solid waste disposal by the Pyrolysis Method, with heat recovery, and (III) conversion of a portion of the thermal system from steam to hot water distribution to increase co-generation capability and as a demonstration system for future expansion. This report presents the conceptual design of the energy system and each Option, with the economic implications identified so that selection of the final system can be made. Draft outline of the Environmental Assessment for the project is submitted as a separate report.

ANALYSIS OF ENERGY EFFICIENCY OF OPERATING MODES OF ELECTRICAL SYSTEMS WITH THE TRACTION LOADS

Directory of Open Access Journals (Sweden)

V. E. Bondarenko

2017-03-01

Full Text Available Innovative scenarios of reliable energy supply of transportation process aimed at reducing the specific energy consumption and increase energy efficiency of the systems of electric traction. The paper suggests innovative energy saving directions in traction networks of railways and new circuit solutions accessing traction substations in energy systems networks, ensure energy security of the transportation process. To ensure the energy security of rail transport special schemes were developed to propose the concept of external power traction substations, which would increase the number of connections to the networks of 220 – 330 kV, as well as the creation of transport and energy corridors, development of its own supply of electric networks of 110 kV substations and mobile RP-110 kV of next generation. Therefore, the investment program of the structures owned by the Ukrainian Railways (Ukrzaliznytsia need to be synchronized in their technological characteristics, as well as the criteria of reliability and quality of power supply with the same external energy investment programs. It is found that without any load on left or right supplying arm one of two less loaded phases of traction transformer begins generating specific modes in the supplying three-phase line. Thus, modes of mobile substation cause leakage in one of the phases of the supply line of traction transformers of active-capacitive current, and as a result generating energy in the main power line of 154 kV, which is fixed and calculated by electricity meters. For these three phase mode supply network is necessary to use 1st algorithm, i.e. taking into account the amount of electricity as the energy in all phases. For effective application of reactive power compensation devices in the AC traction power supply systems it is proposed to develop regulatory documentation on necessity of application and the order of choice of parameters and placement of compensation systems taking into

Analysis of thermal energy storage material with change-of-phase volumetric effects

Science.gov (United States)

Kerslake, Thomas W.; Ibrahim, Mounir B.

1990-01-01

NASA's Space Station Freedom proposed hybrid power system includes photovoltaic arrays with nickel hydrogen batteries for energy storage and solar dynamic collectors driving Brayton heat engines with change-of-phase Thermal Energy Storage (TES) devices. A TES device is comprised of multiple metallic, annular canisters which contain a eutectic composition LiF-CaF2 Phase Change Material (PCM) that melts at 1040 K. A moderately sophisticated LiF-CaF2 PCM computer model is being developed in three stages considering 1-D, 2-D, and 3-D canister geometries, respectively. The 1-D model results indicate that the void has a marked effect on the phase change process due to PCM displacement and dynamic void heat transfer resistance. Equally influential are the effects of different boundary conditions and liquid PCM natural convection. For the second stage, successful numerical techniques used in the 1-D phase change model are extended to a 2-D (r,z) PCM containment canister model. A prototypical PCM containment canister is analyzed and the results are discussed.

Phasing out nuclear in Germany: scenarios of energy policy

International Nuclear Information System (INIS)

Knopf, Brigitte; Pahle, Michael; Kondziella, Hendrik; Goetz, Mario; Bruckner, Thomas; Edenhofer, Ottmar; Stark, Hans; Rittelmeyer, Yann-Sven; Wissmann, Nele; Vitasse, Thomas

2012-02-01

After the German decision taken in 2011 to phase out nuclear, the authors analyse different scenarios of energy transition, and study the consequences of this phasing out in terms of energy needs provided by fossil fuel plants, of electricity price for households and for industries, and of CO 2 emissions. Independently from the development of renewable energies, the different effects of gas and coal plants replacing nuclear energy have been calculated and compared, and other possible scenarios have been explored. The author also discuss requirements in terms of governance for grid development, for a coordinated European policy of energy and climate, and for transparency and scientific follow-up

Phase equilibrium study on system uranium-plutonium-tungsten-carbon

International Nuclear Information System (INIS)

Ugajin, Mitsuhiro

1976-11-01

Metallurgical properties of the U-Pu-W-C system have been studied with emphasis on phases and reactions. Free energy of compound formation, carbon activity and U/Pu segregation in the W-doped carbide fuel are estimated using phase diagram data. The results indicate that tungsten metal is useful as a thermochemical stabilizer of the carbide fuel. Tungsten has high temperature stability in contact with uranium carbide and mixed uranium-plutonium carbide. (auth.)

Investigation of diffusional transport of heat and its enhancement in phase-change thermal energy storage systems

International Nuclear Information System (INIS)

Saraswat, Amit; Bhattacharjee, Rajdeep; Verma, Ankit; Das, Malay K.; Khandekar, Sameer

2017-01-01

Thermal energy storage in general, and phase-change materials (PCMs) in particular, have been a major topic of research for the last thirty years. Due to their favorable thermo-dynamical characteristics, such as high density, specific heat and latent heat of fusion, PCMs are usually employed as working fluids for thermal storage. However, low thermal conductivities of organic PCMs have posed a continuous challenge in its large scale deployment. This study focuses on experimental and numerical investigation of the melting process of industrial grade paraffin wax inside a semi-cylindrical enclosure with a heating strip attached axially along the center of semi-cylinder. During the first part of the study, the solid-liquid interface location, the liquid flow patterns in the melt pool, and the spatial and temporal variation of PCM temperature were recorded. For numerical simulation of the system, open source library OpenFOAM® was used in order to solve the coupled Navier-Stokes and energy equations in the considered system. It is seen that the enthalpy-porosity technique implemented on OpenFOAM® is reasonably well suited for handling melting/solidification problems and can be employed for system level design. Next, to overcome the inherent thermal limitations of PCM storage material, the study further explored the potential of coupling the existing heat source with copper-water heat pipes, so as to help augment the rate of heat dissipation within the medium by increasing the effective system-level thermal conductivity. Integration of heat pipes led to enhanced transport, and hence, a substantial decrease in the total required melting time. The study provides a framework for designing of large systems with integration of heat pipes with PCM based thermal storage systems.

Phase equilibria in the niobium-vanadium-hydrogen system

Energy Technology Data Exchange (ETDEWEB)

Bethin, J. (Grumman Aerospace Corp., Bethpage, NY (USA)); Welch, D.O. (Brookhaven National Lab., Upton, NY (USA)); Pick, M.A. (Commission of the European Communities, Abingdon (UK). JET Joint Undertaking)

1990-01-01

The effect of vanadium additions to niobium on the metal-hydrogen phase equilibria has been studied. Measurements of the equilibrium H{sub 2}(D{sub 2}) pressure-composition-temperature isotherms for Nb{sub 1-x}V{sub x} alloys with 0{le}x<0.2 were used to determine the depression of the {alpha} - {alpha}' critical temperature with increasing vanadium concentration. A simple lattice-fluid model guided reduction of the data. Changes in the triple point temperature as well as the shift of the {zeta} {yields} {epsilon} phase transition were determined by differential scanning calorimetry measurements. A rapid overall depression was found, of the order of 7 K (at.% substituted V){sup -1}, for the metal-hydrogen (deuterium) phase boundary structure when compared with the Nb-H system in the hydrogen concentration range of interest. The results explain the enhanced terminal solubility of hydrogen in this system found previously by other authors. The changes in the phase equilibria are discussed in terms of the effect of hydrogen trapping and compared with the results of a cluster-variation calculation for random-field systems of previous authors, taking into account a distribution of H-site energies due to alloying. (author).

Design and optimization of zero-energy-consumption based solar energy residential building systems

Science.gov (United States)

Zheng, D. L.; Yu, L. J.; Tan, H. W.

2017-11-01

Energy consumption of residential buildings has grown fast in recent years, thus raising a challenge on zero energy residential building (ZERB) systems, which aim at substantially reducing energy consumption of residential buildings. Thus, how to facilitate ZERB has become a hot but difficult topic. In the paper, we put forward the overall design principle of ZERB based on analysis of the systems’ energy demand. In particular, the architecture for both schematic design and passive technology is optimized and both energy simulation analysis and energy balancing analysis are implemented, followed by committing the selection of high-efficiency appliance and renewable energy sources for ZERB residential building. In addition, Chinese classical residential building has been investigated in the proposed case, in which several critical aspects such as building optimization, passive design, PV panel and HVAC system integrated with solar water heater, Phase change materials, natural ventilation, etc., have been taken into consideration.

Late time phase transition as dark energy

Indian Academy of Sciences (India)

Abstract. We show that the dark energy field can naturally be described by the scalar condensates of a non-abelian gauge group. This gauge group is unified with the standard model gauge groups and it has a late time phase transition. The small phase transition explains why the positive acceleration of the universe is ...

Phase equilibria of the Mo-Al-Ho ternary system

Energy Technology Data Exchange (ETDEWEB)

Li, Yitai; Chen, Xiaoxian; Liu, Hao [Guangxi Univ., Nanning (China). College of Materials Science and Engineering; Guangxi Univ., Nanning (China). Guangxi Key Laboratory of Processing for Non-ferrous Metal and Featured Materials; Zhan, Yongzhong [Guangxi Univ., Nanning (China). College of Materials Science and Engineering; Guangxi Univ., Nanning (China). Guangxi Key Laboratory of Processing for Non-ferrous Metal and Featured Materials; Guangxi Univ., Nanning (China). Center of Ecological Collaborative Innovation for Aluminum Industry

2017-08-15

Investigation into the reactions and phase equilibria of transition metal elements (i.e. Mo, Zr, Cr, V and Ti), Al and rare earths is academically and industrially important for the development of both refractory alloys and lightweight high-temperature materials. In this work, the equilibria of the Mo-Al-Ho ternary system at 773 K have been determined by using X-ray powder diffraction and scanning electron microscopy equipped with energy dispersive X-ray analysis. A new ternary phase Al{sub 4}Mo{sub 2}Ho has been found and the other ternary phase Al{sub 43}Mo{sub 4}Ho{sub 6} is observed. Ten binary phases in the Al-Mo and Al-Ho systems, including Al{sub 17}Mo{sub 4} rather than Al{sub 4}Mo, have been determined to exist at 773 K. The homogeneity ranges of AlMo{sub 3} and Al{sub 8}Mo{sub 3} phase are 7.5 at.% and 1 at.%, respectively. According to the phase-disappearing method, the maximum solubility of Al in Mo is about 16 at.%.

Basic study on an energy conversion system using boiling two-phase flows of temperature-sensitive magnetic fluid. Theoretical analysis based on thermal nonequilibrium model and flow visualization using ultrasonic echo

International Nuclear Information System (INIS)

Ishimoto, Jun; Kamiyama, Shinichi; Okubo, Masaaki.

1995-01-01

Effects of magnetic field on the characteristics of boiling two-phase pipe flow of temperature-sensitive magnetic fluid are clarified in detail both theoretically and experimentally. Firstly, governing equations of two-phase magnetic fluid flow based on the thermal nonequilibrium two-fluid model are presented and numerically solved considering evaporation and condensation between gas- and liquid-phases. Next, behaviour of vapor bubbles is visualized with ultrasonic echo in the region of nonuniform magnetic field. This is recorded and processed with an image processor. As a result, the distributions of void fraction in the two-phase flow are obtained. Furthermore, detailed characteristics of the two-phase magnetic fluid flow are investigated using a small test loop of the new energy conversion system. From the numerical and experimental results, it is known that the precise control of the boiling two-phase flow and bubble generation is possible by using the nonuniform magnetic field effectively. These fundamental studies on the characteristics of two-phase magnetic fluid flow will contribute to the development of the new energy conversion system using a gas-liquid boiling two-phase flow of magnetic fluid. (author)

Kinetic Storage as an Energy Management System

International Nuclear Information System (INIS)

Garcia-Tabares, L.

2007-01-01

The possibility of storing energy is increasingly important and necessary. The reason is that storage modifies the basic equation of the energy production balance which states that the power produced should equal the power consumed. When there is a storage device in the grid, this equation is modified such that, in the new balance, the energy produced should equal the algebraic sum of the energy consumed and the energy stored (positive in storage phase and negative when released). This means that the generation profile can be uncoupled from the consumption profile, with the resulting improvement of efficiency. Even small-sized storage systems can be very effective. (Author) 10 refs

Determination of electron bunch shape using transition radiation and phase-energy measurements

International Nuclear Information System (INIS)

Crosson, E.R.; Berryman, K.W.; Richman, B.A.

1995-01-01

We present data comparing microbunch temporal information obtained from electron beam phase-energy measurements with that obtained from transition radiation auto-correlation measurements. The data was taken to resolve some of the ambiguities in previous transition radiation results. By measuring the energy spectrum of the electron beam as a function of its phase relative to the accelerating field, phase-energy information was extracted. This data was analyzed using tomographic techniques to reconstruct the phase-space distribution assuming an electron energy dependence of E(var-phi) = E o + E acc cos(var-phi), where E o is the energy of an electron entering the field, E acc is the peak energy gain, and var-phi is the phase between the crest of the RF wave and an electron. Temporal information about the beam was obtained from the phase space distribution by taking the one dimensional projection along the time axis. We discuss the use of this technique to verify other transition radiation analysis methods

Determination of electron bunch shape using transition radiation and phase-energy measurements

Energy Technology Data Exchange (ETDEWEB)

Crosson, E.R.; Berryman, K.W.; Richman, B.A. [Stanford Univ., CA (United States)] [and others

1995-12-31

We present data comparing microbunch temporal information obtained from electron beam phase-energy measurements with that obtained from transition radiation auto-correlation measurements. The data was taken to resolve some of the ambiguities in previous transition radiation results. By measuring the energy spectrum of the electron beam as a function of its phase relative to the accelerating field, phase-energy information was extracted. This data was analyzed using tomographic techniques to reconstruct the phase-space distribution assuming an electron energy dependence of E({var_phi}) = E{sub o} + E{sub acc}cos({var_phi}), where E{sub o} is the energy of an electron entering the field, E{sub acc} is the peak energy gain, and {var_phi} is the phase between the crest of the RF wave and an electron. Temporal information about the beam was obtained from the phase space distribution by taking the one dimensional projection along the time axis. We discuss the use of this technique to verify other transition radiation analysis methods.

Grid-connected integrated community energy system. Phase II, Stage 2, final report. Executive summary

Energy Technology Data Exchange (ETDEWEB)

1978-03-22

The University of Minnesota Grid-ICES was divided into four identifiable programs in order to study the feasibility of each of the parts of the ICES independently. The total program involves cogeneration, fuel conversion, fuel substitution, and energy conservation by system change. This Phase II report substantiates the theory that the Basic Grid ICES is not only energy-effective, but it will become cost effective as unit operating costs adjust to supply and demand in the 1980's. The Basic Program involves the cogeneration of steam and electricity. The University of Minnesota has been following an orderly process of converting its Central Heating Plant from gas-oil to 100% coal since 1973. The first step in the transition is complete. The University is presently 100% on coal, and will begin the second step, the test burning of low Btu Western coal during the spring, summer, and fall, and high Btu Eastern coal during the high thermal winter period. The final step to 100% Western coal is planned to be completed by 1980. In conjunction with the final step a retired Northern States Power generating plant has been purchased and is in the process of being retrofitted for topping the existing plant steam output during the winter months. The Basic Plan of ICES involves the add-on work and expense of installing additional boiler capacity at Southeast Steam and non-condensing electric generating capability. This will permit the simultaneous generation of electricity and heat dependent upon the thermal requirements of the heating and cooling system in University buildings. This volume presents an overview of the Community and the ICES. (MCW)

Giant Magnetoelectric Energy Conversion Utilizing Inter-Ferroelectric Phase Transformations in Ferroics

Science.gov (United States)

Finkel, Peter; Staruch, Margo

Phase transition-based electromechanical transduction permits achieving a non-resonant broadband mechanical energy conversion see (Finkel et al Actuators, 5 [1] 2. (2015)) , the idea is based on generation high energy density per cycle , at least 100x of magnitude larger than linear piezoelectric type generators in stress biased [011]cut relaxor ferroelectric Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT) single crystal can generate reversible strain >0.35% at remarkably low fields (0.1 MV/m) for tens of millions of cycles. Recently we demonstrated that large strain and polarization rotation can be generated for over 40 x 106cycles with little fatigue by realization of reversible ferroelectric-ferroelectric phase transition in [011] cut PIN-PMN-PT relaxor ferroelectric single crystal while sweeping through the transition with a low applied electric field <0.18 MV/m under mechanical stress. This methodology was extended in the present work to propose magnetoelectric (ME) composite hybrid system comprised of highly magnetostrictive alloymFe81.4Ga18.6 (Galfenol), and lead indium niobate-lead magnesium niobate-lead titanate (PIN-PMN-PT) domain engineered relaxor ferroelectric single crystal. A small time-varying magnetic field applied to this system causes the magnetostrictive element to expand, and the resulting stress forces the phase change in the relaxor ferroelectric single crystal. ME coupling coefficient was fond to achieve 80 V/cm Oe near the FR-FO phase transition that is at least 100X of magnitude higher than any currently reported values.

Gibbs free energy of transfer of a methylene group on {UCON + (sodium or potassium) phosphate salts} aqueous two-phase systems: Hydrophobicity effects

International Nuclear Information System (INIS)

Silverio, Sara C.; Rodriguez, Oscar; Teixeira, Jose A.; Macedo, Eugenia A.

2010-01-01

The Gibbs free energy of transfer of a suitable hydrophobic probe can be regarded as a measure of the relative hydrophobicity of the different phases. The methylene group (CH 2 ) can be considered hydrophobic, and thus be a suitable probe for hydrophobicity. In this work, the partition coefficients of a series of five dinitrophenylated-amino acids were experimentally determined, at 23 o C, in three different tie-lines of the biphasic systems: (UCON + K 2 HPO 4 ), (UCON + potassium phosphate buffer, pH 7), (UCON + KH 2 PO 4 ), (UCON + Na 2 HPO 4 ), (UCON + sodium phosphate buffer, pH 7), and (UCON + NaH 2 PO 4 ). The Gibbs free energy of transfer of CH 2 units were calculated from the partition coefficients and used to compare the relative hydrophobicity of the equilibrium phases. The largest relative hydrophobicity was found for the ATPS formed by dihydrogen phosphate salts.

Aerodynamic performance analysis of an airborne wind turbine system with NREL Phase IV rotor

International Nuclear Information System (INIS)

Saeed, Muhammad; Kim, Man-Hoe

2017-01-01

Highlights: • Aerodynamic predictions for a buoyant airborne system at an altitude of 400 m. • Aerodynamic characteristics of NREL Phase IV rotor operating in a shell casing. • Buoyant shell aerodynamics under varying wind conditions. - Abstract: Wind energy becomes more powerful and consistent with an increase in altitude, therefore, harvesting the wind energy at high altitude results in a naturally restocked source of energy which is cheaper and far more efficient than the conventional wind power system. Airborne wind turbine (AWT), one of the many techniques being employed for this purpose, stands out due to its uninterrupted scheme of energy production. This paper presents the aerodynamic performance of AWT system with NREL Phase IV rotor at an altitude of 400 m. Unsteady simulation of the airborne system has been carried out and variations in the rotor’s torque for a complete revolution are reported and discussed. In order to compare the performance of the shell mounted configuration of Phase IV rotor with its standard test configuration, steady state simulations of the rotor are also conducted under various wind conditions for both configurations. Finally, for stable design of the buoyant airborne system, aerodynamic forces on the shell body are computed and reported.

Up-scaling, formative phases, and learning in the historical diffusion of energy technologies

International Nuclear Information System (INIS)

Wilson, Charlie

2012-01-01

The 20th century has witnessed wholesale transformation in the energy system marked by the pervasive diffusion of both energy supply and end-use technologies. Just as whole industries have grown, so too have unit sizes or capacities. Analysed in combination, these unit level and industry level growth patterns reveal some consistencies across very different energy technologies. First, the up-scaling or increase in unit size of an energy technology comes after an often prolonged period of experimentation with many smaller-scale units. Second, the peak growth phase of an industry can lag these increases in unit size by up to 20 years. Third, the rate and timing of up-scaling at the unit level is subject to countervailing influences of scale economies and heterogeneous market demand. These observed patterns have important implications for experience curve analyses based on time series data covering the up-scaling phases of energy technologies, as these are likely to conflate industry level learning effects with unit level scale effects. The historical diffusion of energy technologies also suggests that low carbon technology policies pushing for significant jumps in unit size before a ‘formative phase’ of experimentation with smaller-scale units are risky. - Highlights: ► Comparative analysis of energy technology diffusion. ► Consistent pattern of sequential formative, up-scaling, and growth phases. ► Evidence for conflation of industry level learning effects with unit level up-scaling. ► Implications for experience curve analyses and technology policy.

Experimental study on heat storage system using phase-change material in a diesel engine

International Nuclear Information System (INIS)

Park, Sangki; Woo, Seungchul; Shon, Jungwook; Lee, Kihyung

2017-01-01

Engines usually use only about 25% of the total fuel energy for power, and the rest is discarded to the cooling water and exhaust gas. Therefore, a technique for utilizing external waste heat is required to improve fuel efficiency in terms of total energy consumption. In this study, a heat storage system was built using a phase-change material in order to recover about 30% of the thermal energy wasted through engine cooling. The components of the heat storage system were divided into phase-change material, a heat exchanger, and a heat-insulating container. For each component, a phase-change material that is suitable for use in vehicles was selected based on the safety, thermal properties, and durability. As a result, a stearic acid of a fatty acid series with natural extracts was determined to be appropriate. In order to measure the reduction in engine fuel consumption, a thermal storage system designed for the actual engine was applied to realize a quick warm-up by releasing stored heat energy directly on the coolant during a cold start. This technique added about 95 calories of heat storage device warm-up time compared to the non-added state, which was reduced by about 18.1% to about 27.1%. - Highlights: • The diesel engine used phase-change material with heat storage system. • The thermal storage system designed for the actual engine. • A stearic acid of a fatty acid series was determined to be appropriate. • Applied heat storage system was reduced by about 18.1%–27.1%.

Energy dependence of critical state of single-component systems

International Nuclear Information System (INIS)

Volchenkova, R.A.

1985-01-01

Equations of critical states of the single-component systems: Psub(cr)(/Psub(o)=(Tsub(cr)/Tsub(o))x0.73, Tsub(cr)=K(Tsub(boil))sup(1.116) and Hsub(cr)(/Hsub(B)=Tsub(sr)/Tsub(B))sup(1.48) where Tsub(B)=1K, Hsub(B)-2 kcal/g-at, K-dimension factor are presented. It is shown that the revealed dependence Hsub(cr)=H(Tsub(cr)) is an energy boundary of a liquid-vapour phase state of the single-component systems beyond limits of which difference between liquid and vapour phases vanishes in increasing the system energy content. The given equations of state are true for all the single-component systems and permit to consider physicomechanical properties of substances in dynamic state depending on external conditions. Critical temperatures and dependences for elements from the most fusible He to infusible W and Re have been calculated

Energy and Cost Saving of a Photovoltaic-Phase Change Materials (PV-PCM System through Temperature Regulation and Performance Enhancement of Photovoltaics

Directory of Open Access Journals (Sweden)

Ahmad Hasan

2014-03-01

Full Text Available The current research seeks to maintain high photovoltaic (PV efficiency and increased operating PV life by maintaining them at a lower temperature. Solid-liquid phase change materials (PCM are integrated into PV panels to absorb excess heat by latent heat absorption mechanism and regulate PV temperature. Electrical and thermal energy efficiency analysis of PV-PCM systems is conducted to evaluate their effectiveness in two different climates. Finally costs incurred due to inclusion of PCM into PV system and the resulting benefits are discussed in this paper. The results show that such systems are financially viable in higher temperature and higher solar radiation environment.

Wigner Functions for the Bateman System on Noncommutative Phase Space

Science.gov (United States)

Heng, Tai-Hua; Lin, Bing-Sheng; Jing, Si-Cong

2010-09-01

We study an important dissipation system, i.e. the Bateman model on noncommutative phase space. Using the method of deformation quantization, we calculate the Exp functions, and then derive the Wigner functions and the corresponding energy spectra.

Wigner Functions for the Bateman System on Noncommutative Phase Space

International Nuclear Information System (INIS)

Tai-Hua, Heng; Bing-Sheng, Lin; Si-Cong, Jing

2010-01-01

We study an important dissipation system, i.e. the Bateman model on noncommutative phase space. Using the method of deformation quantization, we calculate the Exp functions, and then derive the Wigner functions and the corresponding energy spectra

Risk calculations for energy conservation technologies: the likelihood of realizing design-phase expectations in new construction

Energy Technology Data Exchange (ETDEWEB)

Greden, Lara; Vaidya, Prasad; Baker, Chris; Eijadi, David; McDougall, Tom [The Weidt Group (United States)

2007-07-01

The risk that a technology will not be implemented or operated as designed is a significant barrier that impedes owners from adopting new energy-conserving building technologies. This results in a feedback loop that encourages decision makers to minimize risk by sticking with the status quo, regardless of the environmental impact. Different technology categories have different levels and types of risks associated with them.This study assigns levels of risk to technologies by tracing a set of envelope systems, lighting designs, lighting controls, HVAC systems, and HVAC controls in a data set of 38 buildings from the design phase through the initial implementation phase. The likelihood that a technology gets implemented and works as expected is assessed, and risk factors for the various technologies are calculated. Explanations for the levels of risk are supported by interviews with third-party reviewers who serve to assist design teams and owners through the construction phase. Results show that daylighting technologies, including dimming daylighting controls, have the highest risk of not being implemented - when otherwise chosen at the selection phase - while roof insulation and lighting designs are most likely to be fully and correctly implemented. Analysis comparing the risk to the energy conservation opportunity indicates the need for prioritization and support during the design and construction phases to realize expected levels of energy conservation. Overall, the interviewees said the most common reasons for lower than expected energy savings are that energy conservation measures were cut-out during value engineering or cut-out due to later decisions that a technology was functionally risky. This research supports large scale investments in energy conservation technologies for buildings through rebate programs, code improvements, and design guides created by large owners. It identifies technologies that need a higher degree of building management effort and

Phase Control in Nonlinear Systems

Science.gov (United States)

Zambrano, Samuel; Seoane, Jesús M.; Mariño, Inés P.; Sanjuán, Miguel A. F.; Meucci, Riccardo

The following sections are included: * Introduction * Phase Control of Chaos * Description of the model * Numerical exploration of phase control of chaos * Experimental evidence of phase control of chaos * Phase Control of Intermittency in Dynamical Systems * Crisis-induced intermittency and its control * Experimental setup and implementation of the phase control scheme * Phase control of the laser in the pre-crisis regime * Phase control of the intermittency after the crisis * Phase control of the intermittency in the quadratic map * Phase Control of Escapes in Open Dynamical Systems * Control of open dynamical systems * Model description * Numerical simulations and heuristic arguments * Experimental implementation in an electronic circuit * Conclusions and Discussions * Acknowledgments * References

Study on mutual diffusion and phase diagram in the Ni-Ta system

International Nuclear Information System (INIS)

Pimenov, V.N.; Ugaste, Yu.Eh.; Akkushkarova, K.A.

1977-01-01

The mutual diffusion in the Ni-Ta system has been investigated with a view of refining the constitutional diagram. The mutual diffusion factors and their effective values in the various phases and the diffusion activation energies are calculated. Given are the dependences of the phase growth constants and the mutual diffusion factors upon the temperature. The existence of five new phases Ta 2 Ni, TaNi, TaNi 2 , TaNi 3 , TaNi 8 has been discovered in the range of temperatures between 1150 and 1300 deg C. It is established that all the phases have a small concentration range of existence. It is noted that the diffusion characteristics in the phases (mutual diffusion factor and activation energy) differ widely, but fail to correlate with their melting points

Energy Systems Integration Facility News | Energy Systems Integration

Science.gov (United States)

Facility | NREL Energy Systems Integration Facility News Energy Systems Integration Facility Energy Dataset A massive amount of wind data was recently made accessible online, greatly expanding the Energy's National Renewable Energy Laboratory (NREL) has completed technology validation testing for Go

Long term energy system analysis of Japan based on 'options for energy and environment' by the energy and environmental council

International Nuclear Information System (INIS)

Hagiwara, Naoto; Kurosawa, Atsushi

2013-01-01

Implications to Japanese energy system are discussed especially in terms of primary energy supply and power generation portfolio, using sensitivity analysis results by an optimization type energy model based on TIMES modeling framework. We updated energy service demand, efficiency in energy conversion and consumption, and power generation costs based on the recent energy policy document called 'Options for Energy and Environment'. The time horizon of the model is 2050. The sensitivity analysis results are presented for 'Three scenarios for 2030' including nuclear phase out scenarios with/without CO 2 emission constraint. The results are compared with 'Options for Energy and Environment'. (author)

Energy storage systems: a strategic road-book

International Nuclear Information System (INIS)

2011-01-01

Dealing with the development and deployment of thermal and electric energy storage systems, this report first identifies four main challenges: to take environmental challenges into account during all the storage system life (design, production, use, end of life), to integrate the issue of economic valorization of the device into its design phase, to promote the development of standards, to make an institutional and legal framework emerge. It defines the geographical scope and the time horizon for the development of these systems. It evokes research and development programs in the United States, Japan, China, Germany and the European Union. These programs concern: mobile electric storage systems, electric storage systems in support of energy networks and renewable energies, heat storage systems. The authors outline that business models are now favourable to the deployment of storage systems. They discuss some key technological and economical parameters. They propose some prospective visions by 2050 with different possible orientations for this sector. They also identify and discuss the possible technological and socio-economical obstacles, research priorities, and stress the importance of implementing experimental platforms and research demonstrators

Nuclear quantum shape-phase transitions in odd-mass systems

Science.gov (United States)

Quan, S.; Li, Z. P.; Vretenar, D.; Meng, J.

2018-03-01

Microscopic signatures of nuclear ground-state shape-phase transitions in odd-mass Eu isotopes are explored starting from excitation spectra and collective wave functions obtained by diagonalization of a core-quasiparticle coupling Hamiltonian based on energy density functionals. As functions of the physical control parameter—the number of nucleons—theoretical low-energy spectra, two-neutron separation energies, charge isotope shifts, spectroscopic quadrupole moments, and E 2 reduced transition matrix elements accurately reproduce available data and exhibit more-pronounced discontinuities at neutron number N =90 compared with the adjacent even-even Sm and Gd isotopes. The enhancement of the first-order quantum phase transition in odd-mass systems can be attributed to a shape polarization effect of the unpaired proton which, at the critical neutron number, starts predominantly coupling to Gd core nuclei that are characterized by larger quadrupole deformation and weaker proton pairing correlations compared with the corresponding Sm isotopes.

The calculation of phase equilibria of oxide core-concrete systems

International Nuclear Information System (INIS)

Ball, R.G.J.; Mignanelli, M.A.; Barry, T.I.; Gisby, J.A.

1993-01-01

Thermodynamic models have been developed to describe the phase equilibria of oxide solutions appropriate for the understanding of the chemical interactions between nuclear reactor core debris and concrete. For this purpose, the Gibbs energy of the liquid phase is described by the inclusion of associate species and nonideal interactions between the components and associate species. Assessments of the thermodynamic and phase equilibrium data for the subsystems of the CaO-Al 2 O 3 -SiO 2 -UO 2 -ZrO 2 system have been used to obtain a thermodynamic description of the crystalline and liquid phases in good agreement with published data. The data for the subsystems have then been combined, using well established principles, to predict the phase relationships in the ternary and quaternary sytsems and in the overall quinary system. The results show that he overall system cannot properly be treated as a pseudo-ideal liquid and solid solution, as used in some computer codes which attempt to model the physics and chemistry of core-concrete interactions. The limitations of the current model are discussed. (orig.)

Wind energy systems control engineering design

CERN Document Server

Garcia-Sanz, Mario

2012-01-01

IntroductionBroad Context and MotivationConcurrent Engineering: A Road Map for EnergyQuantitative Robust ControlNovel CAD Toolbox for QFT Controller DesignOutline Part I: Advanced Robust Control Techniques: QFT and Nonlinear SwitchingIntroduction to QFTQuantitative Feedback TheoryWhy Feedback? QFT OverviewInsight into the QFT TechniqueBenefits of QFTMISO Analog QFT Control SystemIntroductionQFT Method (Single-Loop MISO System)Design Procedure OutlineMinimum-Phase System Performance SpecificationsJ LTI Plant ModelsPlant Templates of P?(s), P( j_i )Nominal PlantU-Contour (Stability Bound)Trackin

Assessment of correlation energies based on the random-phase approximation

International Nuclear Information System (INIS)

Paier, Joachim; Ren, Xinguo; Rinke, Patrick; Scheffler, Matthias; Scuseria, Gustavo E; Grüneis, Andreas; Kresse, Georg

2012-01-01

The random-phase approximation to the ground state correlation energy (RPA) in combination with exact exchange (EX) has brought the Kohn-Sham (KS) density functional theory one step closer towards a universal, ‘general purpose first-principles method’. In an effort to systematically assess the influence of several correlation energy contributions beyond RPA, this paper presents dissociation energies of small molecules and solids, activation energies for hydrogen transfer and non-hydrogen transfer reactions, as well as reaction energies for a number of common test sets. We benchmark EX + RPA and several flavors of energy functionals going beyond it: second-order screened exchange (SOSEX), single-excitation (SE) corrections, renormalized single-excitation (rSE) corrections and their combinations. Both the SE correction and the SOSEX contribution to the correlation energy significantly improve on the notorious tendency of EX + RPA to underbind. Surprisingly, activation energies obtained using EX + RPA based on a KS reference alone are remarkably accurate. RPA + SOSEX + rSE provides an equal level of accuracy for reaction as well as activation energies and overall gives the most balanced performance, because of which it can be applied to a wide range of systems and chemical reactions. (paper)

Phase transformations and systems driven far from equilibrium

International Nuclear Information System (INIS)

Ma, E.; Atzmon, M.; Bellon, P.; Trivedi, R.

1998-01-01

This volume compiles invited and contributed papers that were presented at Symposium B of the 1997 Materials Research Society Fall Meeting, Phase Transformations and Systems Driven Far From Equilibrium, which was held December 1--5, in Boston, Massachusetts. While this symposium followed the tradition of previous MRS symposia on the fundamental topic of phase transformations, this year the emphasis was on materials systems driven far from equilibrium. The central theme of the majority of the work presented is the understanding of the thermodynamics and kinetics of phase transformations, with significant coverage of metastable materials and externally forced transformations driven, for example, by energy beams or mechanical deformation. The papers are arranged in seven sections: solidification theory and experiments; nucleation; solid state transformations and microstructural evolution; beam-induced transformations; amorphous solids; interfacial and thin film transformations; and nanophases and mechanical alloying. One hundred three papers have been processed separately for inclusion on the data base

Narcissistic Force Meets Systemic Resistance: The Energy Clash Model.

Science.gov (United States)

Sedikides, Constantine; Campbell, W Keith

2017-05-01

This article focuses on the interplay between narcissistic leaders and organizations. It attempts to capture the gist of this interplay with a model outlining the narcissistic organizational trajectory. The Energy Clash Model borrows and adapts a phase/state physics metaphor to conceptualize narcissism as a force that enters or emerges in a stable system (i.e., organization) as a leader, destabilizes it, and stabilizes it at a different state or is expelled. The model consists of three time-contingent phases: perturbation, conflict, and resolution. Narcissists create instability through waves of excitement, proposed reforms, and an inspiring vision for organization's future ( perturbation). With the passage of time, though, systemic awareness and alertness intensify, as organizational costs-in terms of human resources and monetary losses-accrue. Narcissistic energy clashes directly with the organization ( conflict), a clash likely to restabilize the system eventually. The conflict may provoke the exit of the narcissistic leader or his or her accommodation, that is, steps or controls negotiated between the system and the leader ( resolution). Although narcissism is subject to organizational liability, narcissistic energy, when managed and directed properly, may contribute to organizational innovation and evolution. Thus, several interventions for working with narcissistic leaders are discussed.

EB Frond wave energy converter - phase 2

Energy Technology Data Exchange (ETDEWEB)

NONE

2005-07-01

The EB Frond project is a wave energy programme developed by The Engineering Business (EB) from an original idea at Lancaster University. The EB Frond is a wave generator with a collector vane on top of an arm that pivots near the seabed. Phase 1 of the project demonstrated the technical feasibility of the project and provided proof of concept. Phase 2 involved further assesment of the technical and commercial viability of the concept through the development of mathematical and physical modelling methods. The work involved small-scale (1/25th) testing in wave tanks at Newcastle and Lancaster Universities and the development, verification and validation of a time domain mathematical model. The decision by EB to put on hold its renewable generation programme meant that plans to test at an intermediate scale (1/16th), assess different survival strategies in extreme wave conditions, carry out site characterisation for full-scale systems and to produce a robust economic model were not fulfilled. However, the mathematical and physical modelling work was used to develop an economic model for the Frond system. This produced a predicted unit cost of electricity by a pre-commercial 5 MW demonstration farm of about 17 pence/kWh. The report discusses the small-scale testing, test results, mathematical modelling, analysis and interpretation, survivability, the economic model and the development route to full-scale production.

Energy-Efficient Channel Estimation in MIMO Systems

Directory of Open Access Journals (Sweden)

2006-01-01

Full Text Available The emergence of MIMO communications systems as practical high-data-rate wireless communications systems has created several technical challenges to be met. On the one hand, there is potential for enhancing system performance in terms of capacity and diversity. On the other hand, the presence of multiple transceivers at both ends has created additional cost in terms of hardware and energy consumption. For coherent detection as well as to do optimization such as water filling and beamforming, it is essential that the MIMO channel is known. However, due to the presence of multiple transceivers at both the transmitter and receiver, the channel estimation problem is more complicated and costly compared to a SISO system. Several solutions have been proposed to minimize the computational cost, and hence the energy spent in channel estimation of MIMO systems. We present a novel method of minimizing the overall energy consumption. Unlike existing methods, we consider the energy spent during the channel estimation phase which includes transmission of training symbols, storage of those symbols at the receiver, and also channel estimation at the receiver. We develop a model that is independent of the hardware or software used for channel estimation, and use a divide-and-conquer strategy to minimize the overall energy consumption.

Elastic energy and metastable phase equilibria for coherent mixtures in cubic systems

International Nuclear Information System (INIS)

Williams, R.O.

1979-02-01

Expressions were derived for the elastic energy due to coherency for cubic systems for an isotropic structure and for (100) or (111) habit planes for a lamellar structure. For the metastable equilibria the usual tangent compositions are replaced by compositions that are tangent to the elastic energy curve. For a loss of coherency there is an energy decrease due to the elastic effects and a further decrease associated with compositional changes. Information contained within this treatment permits calculation of the x-ray diffraction effects for such structures

Nonstationary signals phase-energy approach-theory and simulations

CERN Document Server

Klein, R; Braun, S; 10.1006/mssp.2001.1398

2001-01-01

Modern time-frequency methods are intended to deal with a variety of nonstationary signals. One specific class, prevalent in the area of rotating machines, is that of harmonic signals of varying frequencies and amplitude. This paper presents a new adaptive phase-energy (APE) approach for time-frequency representation of varying harmonic signals. It is based on the concept of phase (frequency) paths and the instantaneous power spectral density (PSD). It is this path which represents the dynamic behaviour of the system generating the observed signal. The proposed method utilises dynamic filters based on an extended Nyquist theorem, enabling extraction of signal components with optimal signal-to-noise ratio. The APE detects the most energetic harmonic components (frequency paths) in the analysed signal. Tests on simulated signals show the superiority of the APE in resolution and resolving power as compared to STFT and wavelets wave- packet decomposition. The dynamic filters also enable the reconstruction of the ...

Phase equilibrium, crystallization behavior and thermodynamic studies of (m-dinitrobenzene + vanillin) eutectic system

International Nuclear Information System (INIS)

Singh, Jayram; Singh, N.B.

2015-01-01

Graphical abstract: The phase diagram of (m-dinitrobenzene + vanillin) system. - Highlights: • (Thaw + melt) method has shown that (m-dinitrobenzene + vanillin) system forms simple eutectic type phase diagram. • Excess thermodynamic functions showed that eutectic mixture is non-ideal. • The flexural strength measurements have shown that in eutectic mixture, crystallization occurs in an ordered way. - Abstract: The phase diagram of (m-dinitrobenzene + vanillin) system has been studied by the thaw melt method and an eutectic type phase diagram was obtained. The linear velocities of crystallization of the parent components and the eutectic mixture were determined. The enthalpy of fusion of the components and the eutectic mixture were determined using the differential scanning calorimetric technique. Excess Gibbs energy, excess entropy, excess enthalpy of mixing, and interfacial energy have been calculated. FTIR spectroscopic studies and flexural strength measurements were also made. The results have shown that the eutectic is a non-ideal mixture of the two components. On the basis of Jackson’s roughness parameter, it is predicted that the eutectic has faceted morphology

Accelerating Energy Efficiency in Indian Data Centers. Final Report for Phase I Activities

Energy Technology Data Exchange (ETDEWEB)

Ganguly, Suprotim [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Raje, Sanyukta [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Kumar, Satish [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sartor, Dale [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Greenberg, Steve [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2016-01-01

This report documents Phase 1 of the “Accelerating Energy Efficiency in Indian Data Centers” initiative to support the development of an energy efficiency policy framework for Indian data centers. The initiative is being led by the Confederation of Indian Industry (CII), in collaboration with Lawrence Berkeley National Laboratory (LBNL)-U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy, and under the guidance of Bureau of Energy Efficiency (BEE). It is also part of the larger Power and Energy Efficiency Working Group of the US-India Bilateral Energy Dialogue. The initiative consists of two phases: Phase 1 (November 2014 – September 2015) and Phase 2 (October 2015 – September 2016).

Energy infrastructure: hydrogen energy system

Energy Technology Data Exchange (ETDEWEB)

Veziroglu, T N

1979-02-01

In a hydrogen system, hydrogen is not a primary source of energy, but an intermediary, an energy carrier between the primary energy sources and the user. The new unconventional energy sources, such as nuclear breeder reactors, fusion reactors, direct solar radiation, wind energy, ocean thermal energy, and geothermal energy have their shortcomings. These shortcomings of the new sources point out to the need for an intermediary energy system to form the link between the primary energy sources and the user. In such a system, the intermediary energy form must be transportable and storable; economical to produce; and if possible renewable and pollution-free. The above prerequisites are best met by hydrogen. Hydrogen is plentiful in the form of water. It is the cheapest synthetic fuel to manufacture per unit of energy stored in it. It is the least polluting of all of the fuels, and is the lightest and recyclable. In the proposed system, hydrogen would be produced in large plants located away from the consumption centers at the sites where primary new energy sources and water are available. Hydrogen would then be transported to energy consumption centers where it would be used in every application where fossil fuels are being used today. Once such a system is established, it will never be necessary to change to any other energy system.

Energy Systems Integration News | Energy Systems Integration Facility |

Science.gov (United States)

the Energy Systems Integration Facility as part of NREL's work with SolarCity and the Hawaiian Electric Companies. Photo by Amy Glickson, NREL Welcome to Energy Systems Integration News, NREL's monthly date on the latest energy systems integration (ESI) developments at NREL and worldwide. Have an item

Low Energy Nuclear Reaction Aircraft- 2013 ARMD Seedling Fund Phase I Project

Science.gov (United States)

Wells, Douglas P.; McDonald, Robert; Campbell, Robbie; Chase, Adam; Daniel, Jason; Darling, Michael; Green, Clayton; MacGregor, Collin; Sudak, Peter; Sykes, Harrison;

Thermochemical measurements and assessment of the phase diagrams in the system Y-Ba-Cu-O

International Nuclear Information System (INIS)

Boudene, A.; Mohammad, A.

1996-01-01

The aim of this project was to provide a self-consistent set of Gibbs energy data for all phases in the system Y-Ba-Cu-O. Experimental thermochemical investigations by differential thermal analysis (DTA), thermogravimetry (TG), electromotive force measurements (EMF), oxygen coulometric titration (OCT), drop and solution calorimetry, and conventional phase analysis (annealing, quenching, and X-ray diffraction [XRD]) as well as ab initio calculations of interaction energies for the 123 phase have been carried out. The experimental information (phase equilibria, heat capacity, enthalpies of formation, oxygen partial pressures, and so forth) has been used in computer-based assessments of the Gibbs energies. These data have been employed to generate phase diagrams by way of equilibrium computations. All binary and ternary subsystems have been fully assessed. For the quaternary system a dataset covering the subsolidus range has been derived. Applications of the data to practical questions, such as the production of 123 superconductors by an MOCVD process, the producibility of metallic precursors, and the oxidation of a copper-enriched stoichiometric oxide precursor, are demonstrated

Cumulative energy demand and global warming potential of a building-integrated solar thermal system with/without phase change material.

Science.gov (United States)

Lamnatou, Chr; Motte, F; Notton, G; Chemisana, D; Cristofari, C

2018-04-15

Building-integrated solar thermal (BIST) systems are a specific type of solar thermal systems which are integrated into the building and they participate in building functionality. The present article is about the life-cycle assessment of different options of a BIST system (Mediterranean climatic conditions: Ajaccio, France). The environmental profile of the studied configurations is assessed by means of CED (cumulative energy demand), GWP (global warming potential) and EPBT (energy payback time). The proposed configurations (for the collector) include: i) a system without PCM (phase change material) using only rock wool as insulation and ii) a system with PCM (myristic acid) and rock wool. Concerning life-cycle results based on CED and GWP 100a (scenario without recycling), the configuration without PCM shows 0.67 MJ prim /kWh and 0.06 kg CO 2.eq /kWh while the configuration with PCM presents 0.74 MJ prim /kWh and 0.08 kg CO 2.eq /kWh. Regarding EPBT, if the inputs for pumping/auxiliary heating are not taken into account, both configurations (with/without PCM) have almost the same EPBT (about 1.3 years). On the other hand, if the inputs for pumping/auxiliary heating are considered, EPBT is lower for the system with PCM. In addition, scenarios with recycling have been examined and the results demonstrate that recycling considerably improves the environmental profile of the studied configurations. Copyright © 2018 Elsevier Ltd. All rights reserved.

Stand-alone wind system with Vanadium Redox Battery energy storage

DEFF Research Database (Denmark)

Teodorescu, Remus; Barote, L.; Weissbach, R.

2008-01-01

Energy storage devices are required for power balance and power quality in stand alone wind energy systems. A Vanadium Redox Flow Battery (VRB) system has many features which make its integration with a stand-alone wind energy system attractive. This paper proposes the integration of a VRB system...... with a typical stand-alone wind energy system during wind speed variation as well as transient performance under variable load. The investigated system consists of a variable speed wind turbine with permanent magnet synchronous generator (PMSG), diode rectifier bridge, buck-boost converter, bidirectional charge...... controller, transformer, inverter, ac loads and VRB (to store a surplus of wind energy and to supply power during a wind power shortage). The main purpose is to supply domestic appliances through a single phase 230V, 50Hz inverter. Simulations are accomplished in order to validate the stability of the supply....

Phase change materials in energy sector - applications and material requirements

Science.gov (United States)

Kuta, Marta; Wójcik, Tadeusz M.

2015-05-01

Phase change materials (PCMs) have been applying in many areas. One of them is energy field. PCMs are interesting for the energy sector because their use enables thermal stabilization and storage of large amount of heat. It is major issue for safety of electronic devices, thermal control of buildings and vehicles, solar power and many others energy domains. This paper contains preliminary results of research on solid-solid phase change materials designed for thermal stabilisation of electronic devices.

The formation of quasicrystal phase in Al-Cu-Fe system by mechanical alloying

Directory of Open Access Journals (Sweden)

Dilermando Nagle Travessa

2012-10-01

Full Text Available In order to obtain quasicrystalline (QC phase by mechanical alloying (MA in the Al-Cu-Fe system, mixtures of elementary Al, Cu and Fe in the proportion of 65-20-15 (at. % were produced by high energy ball milling (HEBM. A very high energy type mill (spex and short milling times (up to 5 hours were employed. The resulting powders were characterized by X-ray diffraction (XRD, differential scanning calorimetry (DSC and scanning electron microscopy (SEM. QC phase was not directly formed by milling under the conditions employed in this work. However, phase transformations identified by DSC analysis reveals that annealing after HEBM possibly results in the formation of the ψ QC phase.

Preparation and characterization of nano-sized phase change emulsions as thermal energy storage and transport media

International Nuclear Information System (INIS)

Chen, J.; Zhang, P.

2017-01-01

Highlights: • The nano-sized phase change emulsions are prepared by using D-phase method. • The thermo-physical and transport properties are experimentally investigated. • The influence of surfactant on the melting temperature and latent heat of water is clarified. • The phase change emulsion can be used as the heat transfer fluid in a thermal energy storage system. - Abstract: Phase change emulsion (PCE) is a kind of two-phase heat transfer fluid with phase change material (PCM) dispersed in carrier fluid. It has received intensive attractions in recent years due to the fact that it can be used as both the thermal energy storage material and transport medium simultaneously in a thermal energy storage system. In the present study, nano-sized PCEs are prepared by the D-phase method with n-hexadecane and n-octadecane as PCMs. The thermo-physical and transport properties are characterized to facilitate the applications. The droplet size distribution of the PCE is measured by a Photon Correlation Spectroscopy, and the results show that the droplet size distributions are similar at different mass fractions. The rheological behavior and viscosity of the PCE are measured by a rheometer, which shows that the PCEs at mass fractions below 30.0 wt% are Newtonian fluids, and the viscosities are dependent on both the mass fraction and temperature. The differential scanning calorimetry (DSC) is employed to analyze the phase change characteristics of the PCE, and the results indicate large supercooling degree of water and PCM in the PCE. The melting temperature and latent heat of water in the PCE are much smaller than those of pure water. The thermal conductivities of the PCE with different mass fractions at different temperatures are measured by the transient hot-wire method. Furthermore, the energy transport characteristics of the PCEs are evaluated on the basis of the measured thermo-physical and transport properties. The results suggest that the PCEs show a drastic

Solar combi system with phase-change materials; CoSyPCM. Combi-systeme avec materiaux a changement de phase

Energy Technology Data Exchange (ETDEWEB)

Citherlet, S.; Bony, J.

2007-02-15

Within the framework of Task 32 of the Solar Heating and Cooling Programme of the International Energy Agency (IEA) we studied the potential of using Phase Change Material (PCM) in a solar combi system in the form of modules placed in a storage tank. The goal was to analyze the potential of latent heat storage in a water tank of a solar installation, in order to increase the performance or to reduce the storage volume. This report describes the methodology used and the results obtained during the analysis of the heat storage potential by latent heat. The following stages were carried out: (i) Development of a simulation model: As no reliable numerical model exists, we developed a dynamic model to simulate PCM modules of various PCM types and shapes. This simulation model takes into account the hysteresis, the subcooling as well as the internal convection of the PCM in a liquid phase. This model was implemented in an existing TRNSYS Type(60). (ii) Laboratory measurements: In order to validate the digital model we tested various configurations and different types of PCM to check the agreement between simulations and experimental results. This step was focused on the time-dependent temperature distribution in the PCM and in the storage tank in order to validate the numerical model. (iii) Solar combi system: The potential relevance of the PCM was tested by using a solar combi system (Arpege) both with and without PCM. An energy balance was established on the basis of a seven days uninterrupted use of Arpege in various conditions (meteorological conditions and domestic hot water draw-off). Following the validation of the numerical model, annual simulations were carried out. (iv) Environmental impacts: A life cycle analysis of this solar combi system both with and without PCM was carried out. This analysis takes into account materials of the Arpege installation, the PCM and its container, as well as auxiliary energy used. (author)

Phases of the energy system transformation

International Nuclear Information System (INIS)

Fischedick, Manfred; Samadi, Sascha; Hoffmann, Clemens; Henning, Hans-Martin; Pregger, Thomas; Leprich, Uwe; Schmidt, Maike

2015-01-01

The energy transition is an ambitious and highly complex process of transformation. This article presents eight theses that can help to better understand the challenges and to identify starting points for future action and to identify research needs. [de

Public attitudes towards nuclear power and alternative energy systems

International Nuclear Information System (INIS)

1984-10-01

Phase I of this study analyzed attitudes and beliefs of respondents drawn from Metro-Manila. The second phase utilized a sample drawn from residents near a geothermal power plant site in Southern Philippines. Four dimensions of beliefs (psychological/environmental risks, technological benefits/development, economic benefits/implications and socio-political implications/benefits) were identified through factor analysis of belief items on nuclear energy and refined empirically to determine perceptions of respondents about all energy systems. Identification of the relationships between dimensions provided insight into the shared perceptions about each energy system held by the various groups of respondents. The overall attitude of the respondents towards energy systems (nuclear, solar, hydro, geothermal and oil) was determined using three attitude measures: Fishbein model, Osgood's semantic differential technique, and direct response to unfavorability/favorability scale. The belief dimensions were correlated with the attitude measures to determine the degree of contribution of each dimension to attitude. A comparative analysis was made to differentiate attitudes and beliefs held by the PRO and CON nuclear groups, and by the subsamples: university students, science teachers and barangay leaders of the Metro-Manila sample. Attitudes and beliefs relating to the demographic variables were also examined for the two samples. (author)

Social response to nuclear power and alternative energy systems

International Nuclear Information System (INIS)

Savellano, R.A.; Bulaon, C.A.

1986-01-01

Phase I of this study analyzed attitudes and beliefs of respondents drawn from Metro Manila. The second phase utilized a sample drawn from residents near a geothermal power plant site in the Southern Philippines. Four dimensions of beliefs (psychological environmental risks, technological benefits/development, economic benefits/implications, and socio-political/implications/benefit) were identified through factor analysis of beliefs items on nuclear energy and refined empirically to determine perceptions of respondents about all other energy systems. Identification of the relationship between dimensions provided insight into the shared perceptions about each energy system held by the various groups of respondents. The overall attitude of the respondents towards energy systems (nuclear, solar, hydro, geothermal and oil) was determined using three attitude measures: the Fishbein model, Osgood's semantic differential technique, and direct response to unfavorability/favorability scale. The belief dimensions were correlated with the attitude measures to determine the degree of contribution to attitude. A comparative analysis was made to different attitudes and beliefs held by the PRO and CON nuclear groups and by the subsamples: university students, science teachers and barangay leaders of Metro Manila sample. Attitudes and beliefs relating to the demographic variables were also examined for the two samples. (author)

Urban Systems and Energy Consumptions: A Critical Approach

Directory of Open Access Journals (Sweden)

Rocco Papa

2014-05-01

Full Text Available City transformations are also due to the development of new energy sources, which have influenced economy and lifestyles, as well as the physical and functional organization of urban systems. Cities are the key place where it is need to act for the achievement of strategic environmental objectives, such as reducing greenhouse gas emissions and energy saving. The hard resolution of these challenges depends on several factors: their multidimensional nature, the change of the economic and settlement development model, and also the complexity of the relationships between the elements that constitute the urban systems and that affect energy consumption. According to this awareness the Project Smart Energy Master for the energy management of territory financed by PON 04A2_00120 R & C Axis II, from 2012 to 2015 has been developed: it is aimed at supporting local authorities in the development of strategies for the reduction of energy consumption through actions designed to change behavior (in terms of use and energy consumption and to improve the energy efficiency of equipment and infrastructure. With the goal of describing some of the results of the methodological phase of this project, this paper proposes a review of the major studies on the issue of energy consumption at the urban scale in the first section; in the second section the outcomes of the first phase of the development of the comprehension/interpretive model related to the identification of the set of physical/environmental variables at urban scale, that most affect the energy consumption, are described; the third makes a critical review of the reference scientific literature, characterised by a too sectoral approach, compared to the complexity of the topic.

SECA Coal-Based Systems - FuelCell Energy, Inc.

Energy Technology Data Exchange (ETDEWEB)

Ayagh, Hossein [Fuelcell Energy, Inc., Danbury, CT (United States)

2014-01-31

The overall goal of this U.S. Department of Energy (DOE) sponsored project is the development of solid oxide fuel cell (SOFC) cell and stack technology suitable for use in highly-efficient, economically-competitive central generation power plant facilities fueled by coal synthesis gas (syngas). This program incorporates the following supporting objectives: • Reduce SOFC-based electrical power generation system cost to $700 or less (2007 dollars) for a greater than 100 MW Integrated Gasification Fuel Cell (IGFC) power plant, exclusive of coal gasification and CO₂ separation subsystem costs. • Achieve an overall IGFC power plant efficiency of at least 50%, from coal (higher heating value or HHV) to AC power (exclusive of CO₂ compression power requirement). • Reduce the release of CO2 to the environment in an IGFC power plant to no more than 10% of the carbon in the syngas. • Increase SOFC stack reliability to achieve a design life of greater than 40,000 hours. At the inception of the project, the efforts were focused on research, design and testing of prototype planar SOFC power generators for stationary applications. FuelCell Energy, Inc. successfully completed the initial stage of the project by meeting the program metrics, culminating in delivery and testing of a 3 kW system at National Energy Technology Laboratory (NETL). Subsequently, the project was re-aligned into a three phase effort with the main goal to develop SOFC technology for application in coal-fueled power plants with >90% carbon capture. Phase I of the Coal-based efforts focused on cell and stack size scale-up with concurrent enhancement of performance, life, cost, and manufacturing characteristics. Also in Phase I, design and analysis of the baseline (greater than 100 MW) power plant system—including concept identification, system definition, and cost analysis—was conducted. Phase II efforts focused on development of a ≥25 kW SOFC stack tower incorporating

Theoretical potential for low energy consumption phase change memory utilizing electrostatically-induced structural phase transitions in 2D materials

Science.gov (United States)

Rehn, Daniel A.; Li, Yao; Pop, Eric; Reed, Evan J.

2018-01-01

Structural phase-change materials are of great importance for applications in information storage devices. Thermally driven structural phase transitions are employed in phase-change memory to achieve lower programming voltages and potentially lower energy consumption than mainstream nonvolatile memory technologies. However, the waste heat generated by such thermal mechanisms is often not optimized, and could present a limiting factor to widespread use. The potential for electrostatically driven structural phase transitions has recently been predicted and subsequently reported in some two-dimensional materials, providing an athermal mechanism to dynamically control properties of these materials in a nonvolatile fashion while achieving potentially lower energy consumption. In this work, we employ DFT-based calculations to make theoretical comparisons of the energy required to drive electrostatically-induced and thermally-induced phase transitions. Determining theoretical limits in monolayer MoTe2 and thin films of Ge2Sb2Te5, we find that the energy consumption per unit volume of the electrostatically driven phase transition in monolayer MoTe2 at room temperature is 9% of the adiabatic lower limit of the thermally driven phase transition in Ge2Sb2Te5. Furthermore, experimentally reported phase change energy consumption of Ge2Sb2Te5 is 100-10,000 times larger than the adiabatic lower limit due to waste heat flow out of the material, leaving the possibility for energy consumption in monolayer MoTe2-based devices to be orders of magnitude smaller than Ge2Sb2Te5-based devices.

Innovative Phase Change Approach for Significant Energy Savings

Science.gov (United States)

2016-09-01

related to the production, use, transmission , storage, control, or conservation of energy that will – (A) reduce the need for additional energy supplies...Conditions set for operation were: a. The computer with the broadband wireless card is to be used for data collection, transmission and...FINAL REPORT Innovative Phase Change Approach for Significant Energy Savings ESTCP Project EW-201138 SEPTEMBER 2016 Dr. Aly H Shaaban Applied

Advanced Heat/Mass Exchanger Technology for Geothermal and Solar Renewable Energy Systems

Energy Technology Data Exchange (ETDEWEB)

Greiner, Miles [Univ. of Nevada, Reno, NV (United States); Childress, Amy [Univ. of Nevada, Reno, NV (United States); Hiibel, Sage [Univ. of Nevada, Reno, NV (United States); Kim, Kwang [Univ. of Nevada, Reno, NV (United States); Park, Chanwoo [Univ. of Nevada, Reno, NV (United States); Wirtz, Richard [Univ. of Nevada, Reno, NV (United States)

2014-12-16

Northern Nevada has abundant geothermal and solar energy resources, and these renewable energy sources provide an ample opportunity to produce economically viable power. Heat/mass exchangers are essential components to any energy conversion system. Improvements in the heat/mass exchange process will lead to smaller, less costly (more efficient) systems. There is an emerging heat transfer technology, based on micro/nano/molecular-scale surface science that can be applied to heat/mass exchanger design. The objective is to develop and characterize unique coating materials, surface configurations and membranes capable of accommodating a 10-fold increase in heat/mass exchanger performance via phase change processes (boiling, condensation, etc.) and single phase convective heat/mass transfer.

Energy Systems Integration Laboratory | Energy Systems Integration Facility

Science.gov (United States)

| NREL Integration Laboratory Energy Systems Integration Laboratory Research in the Energy Systems Integration Laboratory is advancing engineering knowledge and market deployment of hydrogen technologies. Applications include microgrids, energy storage for renewables integration, and home- and station

Charging-discharging characteristics of macro-encapsulated phase change materials in an active thermal energy storage system for a solar drying kiln

Directory of Open Access Journals (Sweden)

Kumar Shailendra

2017-01-01

Full Text Available The present study explores suitability of two phase change materials (PCM for development of an active thermal storage system for a solar drying kiln by studying their melting and solidification behaviors. A double glass glazing prototype solar kiln was used in the study. The storage system consisted of a water storage tank with PCM placed inside the water in high density polyethylene containers. The water in the tank was heated with help of solar energy using an evacuated tube collector array. The melting and solidification temperature curves of PCM were obtained by charging and discharging the water tank. The study illustrated the utility of the PCM in using the stored thermal energy during their discharge to enhance the temperature inside the kiln. The rate of temperature reduction was found to be higher for paraffin wax as compared to a fatty acid based PCM. The water temperature during the discharge of the PCM showed dependence on the discharge characteristics of each PCM suggesting their suitability in designing active thermal storage systems.

Energy System Analysis of 100 Per cent Renewable Energy Systems

DEFF Research Database (Denmark)

Lund, Henrik; Mathiesen, Brian Vad

2007-01-01

This paper presents the methodology and results of the overall energy system analysis of a 100 per cent renewable energy system. The input for the systems is the result of a project of the Danish Association of Engineers, in which 1600 participants during more than 40 seminars discussed...... and designed a model for the future energy system of Denmark, putting emphasis on energy efficiency, CO2 reduction, and industrial development. The energy system analysis methodology includes hour by hour computer simulations leading to the design of flexible energy systems with the ability to balance...... the electricity supply and demand and to exchange electricity productions on the international electricity markets. The results are detailed system designs and energy balances for two energy target years: year 2050 with 100 per cent renewable energy from biomass and combinations of wind, wave and solar power...

Benchmarking of thermalhydraulic loop models for lead-alloy-cooled advanced nuclear energy systems. Phase I: Isothermal forced convection case

International Nuclear Information System (INIS)

2012-06-01

Under the auspices of the NEA Nuclear Science Committee (NSC), the Working Party on Scientific Issues of the Fuel Cycle (WPFC) has been established to co-ordinate scientific activities regarding various existing and advanced nuclear fuel cycles, including advanced reactor systems, associated chemistry and flowsheets, development and performance of fuel and materials and accelerators and spallation targets. The WPFC has different expert groups to cover a wide range of scientific issues in the field of nuclear fuel cycle. The Task Force on Lead-Alloy-Cooled Advanced Nuclear Energy Systems (LACANES) was created in 2006 to study thermal-hydraulic characteristics of heavy liquid metal coolant loop. The objectives of the task force are to (1) validate thermal-hydraulic loop models for application to LACANES design analysis in participating organisations, by benchmarking with a set of well-characterised lead-alloy coolant loop test data, (2) establish guidelines for quantifying thermal-hydraulic modelling parameters related to friction and heat transfer by lead-alloy coolant and (3) identify specific issues, either in modelling and/or in loop testing, which need to be addressed via possible future work. Nine participants from seven different institutes participated in the first phase of the benchmark. This report provides details of the benchmark specifications, method and code characteristics and results of the preliminary study: pressure loss coefficient and Phase-I. A comparison and analysis of the results will be performed together with Phase-II

Fuel cell power systems for remote applications. Phase 1 final report and business plan

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-02-01

The goal of the Fuel Cell Power Systems for Remote Applications project is to commercialize a 0.1--5 kW integrated fuel cell power system (FCPS). The project targets high value niche markets, including natural gas and oil pipelines, off-grid homes, yachts, telecommunication stations and recreational vehicles. Phase 1 includes the market research, technical and financial analysis of the fuel cell power system, technical and financial requirements to establish manufacturing capability, the business plan, and teaming arrangements. Phase 1 also includes project planning, scope of work, and budgets for Phases 2--4. The project is a cooperative effort of Teledyne Brown Engineering--Energy Systems, Schatz Energy Research Center, Hydrogen Burner Technology, and the City of Palm Desert. Phases 2 through 4 are designed to utilize the results of Phase 1, to further the commercial potential of the fuel cell power system. Phase 2 focuses on research and development of the reformer and fuel cell and is divided into three related, but potentially separate tasks. Budgets and timelines for Phase 2 can be found in section 4 of this report. Phase 2 includes: Task A--Develop a reformate tolerant fuel cell stack and 5 kW reformer; Task B--Assemble and deliver a fuel cell that operates on pure hydrogen to the University of Alaska or another site in Alaska; Task C--Provide support and training to the University of Alaska in the setting up and operating a fuel cell test lab. The Phase 1 research examined the market for power systems for off-grid homes, yachts, telecommunication stations and recreational vehicles. Also included in this report are summaries of the previously conducted market reports that examined power needs for remote locations along natural gas and oil pipelines. A list of highlights from the research can be found in the executive summary of the business plan.

Phase chemistry of the system Nb–Rh–O

International Nuclear Information System (INIS)

Jacob, K.T.; Gupta, Preeti; Vinay, M.; Waseda, Y.

2013-01-01

Phase relations in the system Nb–Rh–O at 1223 K were investigated by isothermal equilibration of eleven compositions and analysis of quenched samples using OM, XRD, SEM and EDS. The oxide phase in equilibrium with the alloy changes progressively from NbO to NbO 2 , NbO 2.422 and Nb 2 O 5−x with increasing Rh. Only one ternary oxide NbRhO 4 with tetragonal structure (a=0.4708 nm and c=0.3017 nm) was detected. It coexists with Rh and Nb 2 O 5 . The standard Gibbs energy of formation of NbRhO 4 from its component binary oxides measured using a solid-state electrochemical cell can be represented by the equation; ΔG f,ox o (J/mol)=−38,350+5.818×T(±96) Constructed on the basis of thermodynamic information of the various alloy and oxide phases are oxygen potential diagram for the system Nb–Rh–O at 1223 K and temperature–composition diagrams at constant partial pressures of oxygen. - Graphical abstract: Isothermal section of ternary phase diagram for the system Nb–Rh–O at 1223 K. - Highlights: • First complete isothermal section for the system Nb–Rh–O has been established. • An electrochemical cell is used to measure the thermodynamic properties of NbRhO 4 . • Oxygen potential diagram at 1223 K is computed from thermodynamic data. • Temperature–composition diagrams at constant oxygen partial pressures. • A complete thermodynamic characterization of the system Nb–Rh–O is presented

Phase chemistry of the system Nb–Rh–O

Energy Technology Data Exchange (ETDEWEB)

Jacob, K.T., E-mail: katob@materials.iisc.ernet.in [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012 (India); Gupta, Preeti; Vinay, M. [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012 (India); Waseda, Y. [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577 (Japan)

2013-06-01

Phase relations in the system Nb–Rh–O at 1223 K were investigated by isothermal equilibration of eleven compositions and analysis of quenched samples using OM, XRD, SEM and EDS. The oxide phase in equilibrium with the alloy changes progressively from NbO to NbO₂, NbO₂.₄₂₂ and Nb₂O_5–x with increasing Rh. Only one ternary oxide NbRhO₄ with tetragonal structure (a=0.4708 nm and c=0.3017 nm) was detected. It coexists with Rh and Nb₂O₅. The standard Gibbs energy of formation of NbRhO₄ from its component binary oxides measured using a solid-state electrochemical cell can be represented by the equation; ΔG_f,ox^o(J/mol)=-38,350+5.818×T(±96) Constructed on the basis of thermodynamic information of the various alloy and oxide phases are oxygen potential diagram for the system Nb–Rh–O at 1223 K and temperature–composition diagrams at constant partial pressures of oxygen. - Graphical abstract: Isothermal section of ternary phase diagram for the system Nb–Rh–O at 1223 K. Highlights: • First complete isothermal section for the system Nb–Rh–O has been established. • An electrochemical cell is used to measure the thermodynamic properties of NbRhO₄. • Oxygen potential diagram at 1223 K is computed from thermodynamic data. • Temperature–composition diagrams at constant oxygen partial pressures. • A complete thermodynamic characterization of the system Nb–Rh–O is presented.

Energy Systems Integration Facility Videos | Energy Systems Integration

Science.gov (United States)

Facility | NREL Energy Systems Integration Facility Videos Energy Systems Integration Facility Integration Facility NREL + SolarCity: Maximizing Solar Power on Electrical Grids Redefining What's Possible for Renewable Energy: Grid Integration Robot-Powered Reliability Testing at NREL's ESIF Microgrid

Selection of high temperature thermal energy storage materials for advanced solar dynamic space power systems

Science.gov (United States)

Lacy, Dovie E.; Coles-Hamilton, Carolyn; Juhasz, Albert

1987-01-01

Under the direction of NASA's Office of Aeronautics and Technology (OAST), the NASA Lewis Research Center has initiated an in-house thermal energy storage program to identify combinations of phase change thermal energy storage media for use with a Brayton and Stirling Advanced Solar Dynamic (ASD) space power system operating between 1070 and 1400 K. A study has been initiated to determine suitable combinations of thermal energy storage (TES) phase change materials (PCM) that result in the smallest and lightest weight ASD power system possible. To date the heats of fusion of several fluoride salt mixtures with melting points greater than 1025 K have been verified experimentally. The study has indicated that these salt systems produce large ASD systems because of their inherent low thermal conductivity and low density. It is desirable to have PCMs with high densities and high thermal conductivities. Therefore, alternate phase change materials based on metallic alloy systems are also being considered as possible TES candidates for future ASD space power systems.

The formation of quasicrystal phase in Al-Cu-Fe system by mechanical alloying

OpenAIRE

Travessa, Dilermando Nagle; Cardoso, Kátia Regina; Wolf, Witor; Jorge Junior, Alberto Moreira; Botta, Walter José

2012-01-01

In order to obtain quasicrystalline (QC) phase by mechanical alloying (MA) in the Al-Cu-Fe system, mixtures of elementary Al, Cu and Fe in the proportion of 65-20-15 (at. %) were produced by high energy ball milling (HEBM). A very high energy type mill (spex) and short milling times (up to 5 hours) were employed. The resulting powders were characterized by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). QC phase was not directly formed ...

The energy efficiency ratio of heat storage in one shell-and-one tube phase change thermal energy storage unit

International Nuclear Information System (INIS)

Wang, Wei-Wei; Wang, Liang-Bi; He, Ya-Ling

2015-01-01

Highlights: • A parameter to indicate the energy efficiency ratio of PCTES units is defined. • The characteristics of the energy efficiency ratio of PCTES units are reported. • A combined parameter of the physical properties of the working mediums is found. • Some implications of the energy efficiency ratio in design of PCTES units are analyzed. - Abstract: From aspect of energy consuming to pump heat transfer fluid, there is no sound basis on which to create an optimum design of a thermal energy storage unit. Thus, it is necessary to develop a parameter to indicate the energy efficiency of such unit. This paper firstly defines a parameter that indicates the ratio of heat storage of phase change thermal energy storage unit to energy consumed in pumping heat transfer fluid, which is called the energy efficiency ratio, then numerically investigates the characteristics of this parameter. The results show that the energy efficiency ratio can clearly indicate the energy efficiency of a phase change thermal energy storage unit. When the fluid flow of a heat transfer fluid is in a laminar state, the energy efficiency ratio is larger than in a turbulent state. The energy efficiency ratio of a shell-and-tube phase change thermal energy storage unit is more sensitive to the outer tube diameter. Under the same working conditions, within the heat transfer fluids studied, the heat storage property of the phase change thermal energy storage unit is best for water as heat transfer fluid. A combined parameter is found to indicate the effects of both the physical properties of phase change material and heat transfer fluid on the energy efficiency ratio

Detroit Lakes energy systems study: Phase I feasibility. Final report, February 1, 1978--July 31, 1978

Energy Technology Data Exchange (ETDEWEB)

None

1978-07-31

The objective of the Detroit Lakes Energy Systems Study is to determine the economic feasibility of alternative renewable energy system configurations in the northern latitudes. A forecast through both 1990 and the year 2000 is made of the demand for electrical energy in the Detroit Lakes area. An assessment of renewable energy resources including biomass, wind, and insolation is provided. A detailed analysis is made of system costs including biomass, wind, solar thermal, solar photovoltaic, selected hybrids, and conventional fuel systems. Lessons learned and recommendations for prototype fabrication are highlighted. (MHR)

Phase-Modulated Optical Communication Systems

CERN Document Server

Ho, Keang-Po

2005-01-01

Fiber-optic communication systems have revolutionized our telecommunication infrastructures – currently, almost all telephone land-line, cellular, and internet communications must travel via some form of optical fibers. In these transmission systems, neither the phase nor frequency of the optical signal carries information – only the intensity of the signal is used. To transmit more information in a single optical carrier, the phase of the optical carrier must be explored. As a result, there is renewed interest in phase-modulated optical communications, mainly in direct-detection DPSK signals for long-haul optical communication systems. When optical amplifiers are used to maintain certain signal level among the fiber link, the system is limited by amplifier noises and fiber nonlinearities. Phase-Modulated Optical Communication Systems surveys this newly popular area, covering the following topics: The transmitter and receiver for phase-modulated coherent lightwave systems Method for performance analysis o...

Single-phase dual-energy CT urography in the evaluation of haematuria

International Nuclear Information System (INIS)

Ascenti, G.; Mileto, A.; Gaeta, M.; Blandino, A.; Mazziotti, S.; Scribano, E.

2013-01-01

Aim: To assess the value of a single-phase dual-energy computed tomography (DECT) urography protocol with synchronous nephrographic–excretory phase enhancement and to calculate the potential dose reduction by omitting the unenhanced scan. Materials and methods: Eighty-four patients referred for haematuria underwent CT urography using a protocol that included single-energy unenhanced and dual-energy contrast-enhanced with synchronous nephrographic–excretory phase scans. DECT-based images [virtual unenhanced (VUE), weighted average, and colour-coded iodine overlay] were reconstructed. Opacification degree by contrast media of the upper urinary tract, and image quality of virtual unenhanced images were independently evaluated using a four-point scale. The diagnostic accuracy in detecting urothelial tumours on DECT-based images was determined. The dose of a theoretical dual-phase single-energy protocol was obtained by multiplying the effective dose of the unenhanced single-energy acquisition by two. Radiation dose saving by omitting the unenhanced scan was calculated. Results: The degree of opacification was scored as optimal or good in 86.9% of cases (k = 0.72); VUE image quality was excellent or good in 83.3% of cases (k = 0.82). Sensitivity, specificity, positive predictive value, and negative predictive value for urothelial tumours detection were 85.7, 98.6, 92.3, and 97.1%. Omission of the unenhanced scan led to a mean dose reduction of 42.7 ± 5%. Conclusion: Single-phase DECT urography with synchronous nephrographic–excretory phase enhancement represents an accurate “all-in-one’’ approach with a radiation dose saving up to 45% compared with a standard dual-phase protocol.

Energy flow theory of nonlinear dynamical systems with applications

CERN Document Server

Xing, Jing Tang

2015-01-01

This monograph develops a generalised energy flow theory to investigate non-linear dynamical systems governed by ordinary differential equations in phase space and often met in various science and engineering fields. Important nonlinear phenomena such as, stabilities, periodical orbits, bifurcations and chaos are tack-led and the corresponding energy flow behaviors are revealed using the proposed energy flow approach. As examples, the common interested nonlinear dynamical systems, such as, Duffing’s oscillator, Van der Pol’s equation, Lorenz attractor, Rössler one and SD oscillator, etc, are discussed. This monograph lights a new energy flow research direction for nonlinear dynamics. A generalised Matlab code with User Manuel is provided for readers to conduct the energy flow analysis of their nonlinear dynamical systems. Throughout the monograph the author continuously returns to some examples in each chapter to illustrate the applications of the discussed theory and approaches. The book can be used as ...

Electron Energy Confinement for HHFW Heating and Current Drive Phasing on NSTX

International Nuclear Information System (INIS)

Hosea, J.C.; Bernabei, S.; Biewer, T.; LeBlanc, B.; Phillips, C.K.; Wilson, J.R.; Stutman, D.; Ryan, P.; Swain, D.W.

2005-01-01

Thomson scattering laser pulses are synchronized relative to modulated HHFW power to permit evaluation of the electron energy confinement time during and following HHFW pulses for both heating and current drive antenna phasing. Profile changes resulting from instabilities require that the total electron stored energy, evaluated by integrating the midplane electron pressure P(sub)e(R) over the magnetic surfaces prescribed by EFIT analysis, be used to derive the electron energy confinement time. Core confinement is reduced during a sawtooth instability but, although the electron energy is distributed outward by the sawtooth, the bulk electron energy confinement time is essentially unaffected. The radial deposition of energy into the electrons is noticeably more peaked for current drive phasing (longer wavelength excitation) relative to that for heating phasing (shorter wavelength excitation) as is expected theoretically. However, the power delivered to the core plasma is reduced consider ably for the current drive phasing, indicating that surface/peripheral damping processes play a more important role for this case

Energy Performance of Water-based and Air-based Cooling Systems in Plus-energy Housing

DEFF Research Database (Denmark)

Andersen, Mads E.; Schøtt, Jacob; Kazanci, Ongun Berk

2016-01-01

-space, and air-to-water heat pump vs. ground heat exchanger as cooling source) on the system energy performance were investigated while achieving the same thermal indoor conditions. The results show that the water-based floor cooling system performed better than the air-based cooling system in terms of energy...... energy use reductions. The coupling of radiant floor with the ground enables to obtain “free” cooling, although the brine pump power should be kept to a minimum to fully take advantage of this solution. By implementing a ground heat exchanger instead of the heat pump and use the crawl-space air as intake...... air an improvement of 37% was achieved. The cooling demand should be minimized in the design phase as a priority and then the resulting cooling load should be addressed with the most energy efficient cooling strategy. The floor cooling coupled with a ground heat exchanger was shown to be an effective...

FLYWHEEL ENERGY STORAGE SYSTEMS WITH SUPERCONDUCTING BEARINGS FOR UTILITY APPLICATIONS

Energy Technology Data Exchange (ETDEWEB)

Dr. Michael Strasik; Mr. Arthur Day; Mr. Philip Johnson; Dr. John Hull

2007-10-26

This project’s mission was to achieve significant advances in the practical application of bulk high-temperature superconductor (HTS) materials to energy-storage systems. The ultimate product was planned as an operational prototype of a flywheel system on an HTS suspension. While the final prototype flywheel did not complete the final offsite demonstration phase of the program, invaluable lessons learned were captured on the laboratory demonstration units that will lead to the successful deployment of a future HTS-stabilized, composite-flywheel energy-storage system (FESS).

FLYWHEEL ENERGY STORAGE SYSTEMS WITH SUPERCONDUCTING BEARINGS FOR UTILITY APPLICATIONS

International Nuclear Information System (INIS)

Dr. Michael Strasik; Mr. Arthur Day; Mr. Philip Johnson; Dr. John Hull

2007-01-01

This project's mission was to achieve significant advances in the practical application of bulk high-temperature superconductor (HTS) materials to energy-storage systems. The ultimate product was planned as an operational prototype of a flywheel system on an HTS suspension. While the final prototype flywheel did not complete the final offsite demonstration phase of the program, invaluable lessons learned were captured on the laboratory demonstration units that will lead to the successful deployment of a future HTS-stabilized, composite-flywheel energy-storage system (FESS)

Lyotropic liquid crystalline phase behaviour in amphiphile-protic ionic liquid systems.

Science.gov (United States)

Chen, Zhengfei; Greaves, Tamar L; Fong, Celesta; Caruso, Rachel A; Drummond, Calum J

2012-03-21

Approximate partial phase diagrams for nine amphiphile-protic ionic liquid (PIL) systems have been determined by synchrotron source small angle X-ray scattering, differential scanning calorimetry and cross polarised optical microscopy. The binary phase diagrams of some common cationic (hexadecyltrimethyl ammonium chloride, CTAC, and hexadecylpyridinium bromide, HDPB) and nonionic (polyoxyethylene (10) oleyl ether, Brij 97, and Pluronic block copolymer, P123) amphiphiles with the PILs, ethylammonium nitrate (EAN), ethanolammonium nitrate (EOAN) and diethanolammonium formate (DEOAF), have been studied. The phase diagrams were constructed for concentrations from 10 wt% to 80 wt% amphiphile, in the temperature range 25 °C to >100 °C. Lyotropic liquid crystalline phases (hexagonal, cubic and lamellar) were formed at high surfactant concentrations (typically >50 wt%), whereas at thermal stability of the phases formed by these surfactants persisted to temperatures above 100 °C. The phase behaviour of amphiphile-PIL systems was interpreted by considering the PIL cohesive energy, liquid nanoscale order, polarity and ionicity. For comparison the phase behaviour of the four amphiphiles was also studied in water.

Energy Systems Integration News | Energy Systems Integration Facility |

Science.gov (United States)

organization and independent system operator settle energy transactions in its real-time markets at the same time interval it dispatches energy, and settle operating reserves transactions in its real-time markets the electric grid. These control systems will enable real-time coordination between distributed energy

Energy Systems High-Pressure Test Laboratory | Energy Systems Integration

Science.gov (United States)

Facility | NREL Energy Systems High-Pressure Test Laboratory Energy Systems High-Pressure Test Laboratory In the Energy Systems Integration Facility's High-Pressure Test Laboratory, researchers can safely test high-pressure hydrogen components. Photo of researchers running an experiment with a hydrogen fuel

Thermoelectric Energy Harvesting Using Phase Change Materials (PCMs) in High Temperature Environments in Aircraft

Science.gov (United States)

Elefsiniotis, A.; Becker, Th.; Schmid, U.

2014-06-01

Wireless, energy-autonomous structural health-monitoring systems in aircraft have the potential of reducing total maintenance costs. Thermoelectric energy harvesting, which seems the best choice for creating truly autonomous health monitoring sensors, is the principle behind converting waste heat to useful electrical energy through the use of thermoelectric generators. To enhance the temperature difference across the two sides of a thermoelectric generator, i.e. increasing heat flux and energy production, a phase change material acting as thermal mass is attached on one side of the thermoelectric generators while the other side is placed on the aircraft structure. The application area under investigation for this paper is the pylon aft fairing, located near the engine of an aircraft, with temperatures reaching on the inside up to 350 °C. Given these harsh operational conditions, the performance of a device, containing erythritol as a phase change material, is evaluated. The harvested energy reaching values up to 81.4 J can be regulated by a power management module capable of storing the excess energy and recovering it from the medium powering a sensor node and a wireless transceiver.

Hanstholm phase 2B. Offshore wave energy test 1994 - 1996

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-11-01

The wave power converter consists of a float 2.5 meter in diameter, connected by a rope to a seabed-mounted piston pump, installed on 25 meter deep water 2,5 km offshore Hanstholm, Denmark. The converter is designed to absorb an average maximum power of 1 kW. Measured data in real sea conditions are compared to results based on computer simulations and previous tank testing. Losses caused by rope elasticity and hysteresis, friction in the pump and back flow through the valves are assessed. The economic perspectives of a large wave power plant are presented, based on a revised prototype incorporating the results and experience gained during the test period. The wave energy conversion test `Hanstholm phase 2B` has showed, that it it technically possible to exploit the offshore wave energy resource. This source of energy could become attractive for commercial enterprise. The wave power converter demonstrated a reliable performance over a period of nine months. It produced energy under all wave conditions and survived storm waves of 9,6 m. A 300 MW wave power plant in the Danish part of the North sea is estimated to produce electricity at a cost between 2,1 - 2,4 DKK/kWh. The electrical transmission to shore contribute to approximately 20% of the cost. New data predict a potential of 23 kW per meter wave front. The energy plan Energy 21 proposed by the Danish Department of Energy, includes a scenario incorporating wave energy in the energy system year 2030. A strategy for the development of wave energy, has been proposed as part of the project OWEC-1 supported by the European Joule R and D programme. A proposal for future Danish initiatives to develop second generation point absorber systems is outlined. (ARW) 29 refs.

User's manual of BISHOP. A Bi-Phase, Sodium-Hydrogen-Oxygen system, chemical equilibrium calculation program

International Nuclear Information System (INIS)

Okano, Yasushi; Yamaguchi, Akira

2001-07-01

In an event of sodium leakage in liquid metal fast breeder reactors, liquid sodium flows out of piping, and droplet combustion might occur under a certain environmental condition. The combustion heat and reaction products should be evaluated in the sodium fire analysis codes for investigating the influence of the sodium leak age and fire incident. In order to analyze the reaction heat and products, the multi-phase chemical equilibrium calculation program for a sodium, oxygen and hydrogen system has been developed. The developed numerical program is named BISHOP, which denotes 'Bi-Phase, Sodium-Hydrogen-Oxygen, Chemical Equilibrium Calculation Program'. The Gibbs free energy minimization method is used because of the following advantages. Chemical species are easily added and changed. A variety of thermodynamic states, such as isothermal and isentropic changes, can be dealt with in addition to constant temperature and pressure processes. In applying the free energy minimization method to solve the multi-phase sodium reaction system, three new numerical calculation techniques are developed. One is theoretical simplification of phase description in equation system, the other is to extend the Gibbs free energy minimization method to a multi-phase system, and the last is to establish the efficient search for the minimum value. The reaction heat and products at the equilibrium state can be evaluated from the initial conditions, such as temperature, pressure and reactants, using BISHOP. This report describes the thermochemical basis of chemical equilibrium calculations, the system of equations, simplification models, and the procedure to prepare input data and usage of BISHOP. (author)

Balance of liquid-phase turbulence kinetic energy equation for bubble-train flow

International Nuclear Information System (INIS)

Ilic, Milica; Woerner, Martin; Cacuci, Dan Gabriel

2004-01-01

In this paper the investigation of bubble-induced turbulence using direct numerical simulation (DNS) of bubbly two-phase flow is reported. DNS computations are performed for a bubble-driven liquid motion induced by a regular train of ellipsoidal bubbles rising through an initially stagnant liquid within a plane vertical channel. DNS data are used to evaluate balance terms in the balance equation for the liquid phase turbulence kinetic energy. The evaluation comprises single-phase-like terms (diffusion, dissipation and production) as well as the interfacial term. Special emphasis is placed on the procedure for evaluation of interfacial quantities. Quantitative analysis of the balance equation for the liquid phase turbulence kinetic energy shows the importance of the interfacial term which is the only source term. The DNS results are further used to validate closure assumptions employed in modelling of the liquid phase turbulence kinetic energy transport in gas-liquid bubbly flows. In this context, the performance of respective closure relations in the transport equation for liquid turbulence kinetic energy within the two-phase k-ε and the two-phase k-l model is evaluated. (author)

Fast ferroelectric phase shifters for energy recovery linacs

Directory of Open Access Journals (Sweden)

S. Yu Kazakov

2010-11-01

Full Text Available Fast phase shifters are described that use a novel barium strontium titanate ceramic that can rapidly change its dielectric constant as an external bias voltage is changed. These phase shifters promise to reduce by ∼10 times the power requirements for the rf source needed to drive an energy recovery linac (ERL. Such phase shifters will be coupled with superconducting radiofrequency cavities so as to tune them to compensate for phase instabilities, whether beam-driven or those caused by microphonics. The most promising design is presented, which was successfully cold tested and demonstrated a switching speed of ∼30  ns for 77 deg, corresponding to <0.5  ns per deg of rf phase. Other crucial issues (losses, phase shift values, etc. are discussed.

Single-phase dual-energy CT urography in the evaluation of haematuria.

Science.gov (United States)

Ascenti, G; Mileto, A; Gaeta, M; Blandino, A; Mazziotti, S; Scribano, E

2013-02-01

To assess the value of a single-phase dual-energy computed tomography (DECT) urography protocol with synchronous nephrographic-excretory phase enhancement and to calculate the potential dose reduction by omitting the unenhanced scan. Eighty-four patients referred for haematuria underwent CT urography using a protocol that included single-energy unenhanced and dual-energy contrast-enhanced with synchronous nephrographic-excretory phase scans. DECT-based images [virtual unenhanced (VUE), weighted average, and colour-coded iodine overlay] were reconstructed. Opacification degree by contrast media of the upper urinary tract, and image quality of virtual unenhanced images were independently evaluated using a four-point scale. The diagnostic accuracy in detecting urothelial tumours on DECT-based images was determined. The dose of a theoretical dual-phase single-energy protocol was obtained by multiplying the effective dose of the unenhanced single-energy acquisition by two. Radiation dose saving by omitting the unenhanced scan was calculated. The degree of opacification was scored as optimal or good in 86.9% of cases (k = 0.72); VUE image quality was excellent or good in 83.3% of cases (k = 0.82). Sensitivity, specificity, positive predictive value, and negative predictive value for urothelial tumours detection were 85.7, 98.6, 92.3, and 97.1%. Omission of the unenhanced scan led to a mean dose reduction of 42.7 ± 5%. Single-phase DECT urography with synchronous nephrographic-excretory phase enhancement represents an accurate "all-in-one'' approach with a radiation dose saving up to 45% compared with a standard dual-phase protocol. Copyright © 2012 The Royal College of Radiologists. All rights reserved.

Development, Demonstration, and Field Testing of Enterprise-Wide Distributed Generation Energy Management System: Phase 1 Report

Energy Technology Data Exchange (ETDEWEB)

2003-04-01

This report describes RealEnergy's evolving distributed generation command and control system, called the"Distributed Energy Information System" (DEIS). This system uses algorithms to determine how to operate distributed generation systems efficiently and profitably. The report describes the system and RealEnergy's experiences in installing and applying the system to manage distributed generators for commercial building applications.The report is divided into six tasks. The first five describe the DEIS; the sixth describes RE's regulatory and contractual obligations: Task 1: Define Information and Communications Requirements; Task 2: Develop Command and Control Algorithms for Optimal Dispatch; Task 3: Develop Codes and Modules for Optimal Dispatch Algorithms; Task 4: Test Codes Using Simulated Data; Task 5: Install and Test Energy Management Software; Task 6: Contractual and Regulatory Issues.

Open-Phase Condition Detecting System for Transformers in Nuclear Power Plant

International Nuclear Information System (INIS)

Ha, Che-Wung; Lee, Do-Hwan

2015-01-01

Recently, several events involving the loss of one of the three phases of the offsite power circuit occurred in the US nuclear power plants (NPPs).. In some cases, the open-phase condition existed undetected for an extended period and in other case, was not properly responded to. Accordingly, the Nuclear Regulatory Commission (NRC) requested all license holders to take corrective actions to address the open-phase condition. It was also requested that all holders or applicant for a standard design certification (DC) include a description of a protection system to detect and separate the open circuit into design control document (DCD). Currently, NPPs including Duke Energy, Exelon, and institutes including Electric Power Research Institute (EPRI) are working together to resolve issues associated with detecting an open-phase condition. This paper, using Electromagnetic Transients Program (EMTP), presents a system to detect and address the loss of one of three phases of the offsite power circuit connected to main, auxiliary and standby transformers, which is hard to be detected in the current protection system. This paper, using EMTP, presents a system to detect and address the loss of one of three phases of the offsite power circuit running to MT, UAT or SAT which is hard to be detected in the current protection system. The system presented in this paper will be useful not only for the KHNP to meet the NRC requirement, but also for nuclear power plants at home and abroad to take corrective actions to provide protection from a single phase open circuit condition for offsite power sources

Open-Phase Condition Detecting System for Transformers in Nuclear Power Plant

Energy Technology Data Exchange (ETDEWEB)

Ha, Che-Wung; Lee, Do-Hwan [KHNP Central Research Institute, Daejeon (Korea, Republic of)

2015-05-15

Recently, several events involving the loss of one of the three phases of the offsite power circuit occurred in the US nuclear power plants (NPPs).. In some cases, the open-phase condition existed undetected for an extended period and in other case, was not properly responded to. Accordingly, the Nuclear Regulatory Commission (NRC) requested all license holders to take corrective actions to address the open-phase condition. It was also requested that all holders or applicant for a standard design certification (DC) include a description of a protection system to detect and separate the open circuit into design control document (DCD). Currently, NPPs including Duke Energy, Exelon, and institutes including Electric Power Research Institute (EPRI) are working together to resolve issues associated with detecting an open-phase condition. This paper, using Electromagnetic Transients Program (EMTP), presents a system to detect and address the loss of one of three phases of the offsite power circuit connected to main, auxiliary and standby transformers, which is hard to be detected in the current protection system. This paper, using EMTP, presents a system to detect and address the loss of one of three phases of the offsite power circuit running to MT, UAT or SAT which is hard to be detected in the current protection system. The system presented in this paper will be useful not only for the KHNP to meet the NRC requirement, but also for nuclear power plants at home and abroad to take corrective actions to provide protection from a single phase open circuit condition for offsite power sources.

Solid state phase change materials for thermal energy storage in passive solar heated buildings

Science.gov (United States)

Benson, D. K.; Christensen, C.

1983-11-01

A set of solid state phase change materials was evaluated for possible use in passive solar thermal energy storage systems. The most promising materials are organic solid solutions of pentaerythritol, pentaglycerine and neopentyl glycol. Solid solution mixtures of these compounds can be tailored so that they exhibit solid-to-solid phase transformations at any desired temperature within the range from less than 25 deg to 188 deg. Thermophysical properties such as thermal conductivity, density and volumetric expansion were measured. Computer simulations were used to predict the performance of various Trombe wall designs incorporating solid state phase change materials. Optimum performance was found to be sensitive to the choice of phase change temperatures and to the thermal conductivity of the phase change material. A molecular mechanism of the solid state phase transition is proposed and supported by infrared spectroscopic evidence.

Energy and economic analysis of a building enclosure outfitted with a phase change material board (PCMB)

International Nuclear Information System (INIS)

Sun, Xiaoqin; Zhang, Quan; Medina, Mario A.; Lee, Kyoung Ok

2014-01-01

Highlights: • Phase change material boards (PCMBs) were simulated in building enclosures. • Energy and economic savings for these buildings were estimated. • The buildings were located in five cities with different climatic conditions. • The energy savings ratio was 100% when a cold energy source was used. • A mean electricity savings ratio of 13.1% was obtained. - Abstract: This paper presents energy and economic analyses related to the application of phase change materials boards (PCMBs) in building enclosures during the cooling season. A heat transfer model was developed, which was implemented via a computer program. Simulations were carried out using weather data files from five cities located in five different climate regions in China. Energy savings from using a natural cold source (e.g., outdoor air) and electricity savings from a reduction in electricity by air conditioning systems were evaluated. The energy savings ratio (ESR) and simple payback period (SPP) were used to assess the application of PCMBs in building enclosures. The selection of optimum phase transition temperatures for the PCMs for the various climates was made using indoor and outdoor air temperatures, as well as SPP. For space cooling purposes, it was suggested that phase transition temperatures should be at least 3 °C higher than the mean outdoor air temperature. Simple payback period suggested the possibility of the cost effective use of PCMBs in occupied buildings for moderate temperature climates

Phase-change-materials as energy source for micro aerial vehicles (MAV)

International Nuclear Information System (INIS)

Lidor, A.; Sher, E.; Weihs, D.

2014-01-01

While there are many different challenges in the development of micro aerial vehicles (MAV), one of the severe limiting factors in terms of weight is the energy storage/power system. Most of the MAVs developed to date are based on electrical motors. In the present study, several potential alternative energy storage/power systems are examined, evaluated for their specific energy and specific power, and compared to electrical batteries and hydrocarbon fuel storage. Analysis of the power and energy requirements of different MAV configurations, suggests that a specific power of 35–60 W/kg for fixed wing MAV and 65–85 W/kg for rotary wing MAV are needed. The required specific energy for a short mission of 20 min is 15–25 W h/kg for fixed wing MAV and 30–40 W h/kg for rotary wing MAV. Based on these requirements, a novel PCM open-cycle storage/power system is proposed. It comprises of an open cycle that uses the ambient temperature as its hot reservoir. Promising initial results, in terms of specific power (45–70 W/kg), specific energy (24–45 W h/kg) and open-cycle thermodynamic efficiency (22–54%), are presented. Owing to the high potential of the proposed PCM open-cycle, we believe that the development of new PCM materials specifically designed for this purpose is highly deserving. - Highlights: •A novel phase change material open-cycle is proposed for micro aerial vehicles. •The ambient is used as its hot reservoir. •Analysis shows promising results in terms of specific energy and thermal efficiency

Low concentration graphene nanoplatelets for shape stabilization and thermal transfer reinforcement of Mannitol: a phase change material for a medium-temperature thermal energy system

Science.gov (United States)

Jing, Gu; Dehong, Xia; Li, Wang; Wenqing, Ao; Zhaodong, Qi

2018-03-01

We report herein a novel series of Mannitol/GNPs (graphene nanoplatelets) composites with incremental GNPs loadings from 1 wt% to 10 wt% for further applications in medium-temperature thermal energy system. The phase change behavior and thermal conductivity of Mannitol/GNPs composite, a nanostructured PCM, have been evaluated as a function of GNPs content. Compared to the pristine Mannitol, the resultant stabilized composite with 8 wt% of GNPs displays an extremely high 1054% enhancement in thermal conductivity, and inherits 92% of phase change enthalpy of bulk Mannitol PCM (phase change material). More importantly, 92%Mannitol/GNPs composite still preserves its initial shape without any leakage even when subjected to a 400 consecutive melting/re-solidification cycles. The resulting Mannitol composites exhibit excellent chemical compatibility, large phase change enthalpy and improved thermal reliability, as compared to base PCM, which stands distinct in its class of organic with reference to the past literatures.

A review on phase change energy storage: materials and applications

International Nuclear Information System (INIS)

Farid, Mohammed M.; Khudhair, Amar M.; Razack, Siddique Ali K.; Al-Hallaj, Said

2004-01-01

Latent heat storage is one of the most efficient ways of storing thermal energy. Unlike the sensible heat storage method, the latent heat storage method provides much higher storage density, with a smaller temperature difference between storing and releasing heat. This paper reviews previous work on latent heat storage and provides an insight to recent efforts to develop new classes of phase change materials (PCMs) for use in energy storage. Three aspects have been the focus of this review: PCM materials, encapsulation and applications. There are large numbers of phase change materials that melt and solidify at a wide range of temperatures, making them attractive in a number of applications. Paraffin waxes are cheap and have moderate thermal energy storage density but low thermal conductivity and, hence, require large surface area. Hydrated salts have larger energy storage density and higher thermal conductivity but experience supercooling and phase segregation, and hence, their application requires the use of some nucleating and thickening agents. The main advantages of PCM encapsulation are providing large heat transfer area, reduction of the PCMs reactivity towards the outside environment and controlling the changes in volume of the storage materials as phase change occurs. The different applications in which the phase change method of heat storage can be applied are also reviewed in this paper. The problems associated with the application of PCMs with regards to the material and the methods used to contain them are also discussed

Energy systems

Energy Technology Data Exchange (ETDEWEB)

Haefele, W [Nuclear Research Centre, Applied Systems Analysis and Reactor Physics, Karlsruhe (Germany); International Institute for Applied Systems Analysis, Laxenburg (Austria)

1974-07-01

Up to the present the production, transmission and distribution of energy has been considered mostly as a fragmented problem; at best only subsystems have been considered. Today the scale of energy utilization is increasing rapidly, and correspondingly, the reliance of societies on energy. Such strong quantitative increases influence the qualitative nature of energy utilization in most of its aspects. Resources, reserves, reliability and environment are among the key words that may characterize the change in the nature of the energy utilization problem. Energy can no longer be considered an isolated technical and economical problem, rather it is embedded in the ecosphere and the society-technology complex. Restraints and boundary conditions have to be taken into account with the same degree of attention as in traditional technical problems, for example a steam turbine. This results in a strong degree of interweaving. Further, the purpose of providing energy becomes more visible, that is, to make survival possible in a civilized and highly populated world on a finite globe. Because of such interweaving and finiteness it is felt that energy should be considered as a system and therefore the term 'energy systems' is used. The production of energy is only one component of such a system; the handling of energy and the embedding of energy into the global and social complex in terms of ecology, economy, risks and resources are of similar importance. he systems approach to the energy problem needs more explanation. This paper is meant to give an outline of the underlying problems and it is hoped that by so doing the wide range of sometimes confusing voices about energy can be better understood. Such confusion starts already with the term 'energy crisis'. Is there an energy crisis or not? Much future work is required to tackle the problems of energy systems. This paper can only marginally help in that respect. But it is hoped that it will help understand the scope of the

Energy systems

International Nuclear Information System (INIS)

Haefele, W.

1974-01-01

Up to the present the production, transmission and distribution of energy has been considered mostly as a fragmented problem; at best only subsystems have been considered. Today the scale of energy utilization is increasing rapidly, and correspondingly, the reliance of societies on energy. Such strong quantitative increases influence the qualitative nature of energy utilization in most of its aspects. Resources, reserves, reliability and environment are among the key words that may characterize the change in the nature of the energy utilization problem. Energy can no longer be considered an isolated technical and economical problem, rather it is embedded in the ecosphere and the society-technology complex. Restraints and boundary conditions have to be taken into account with the same degree of attention as in traditional technical problems, for example a steam turbine. This results in a strong degree of interweaving. Further, the purpose of providing energy becomes more visible, that is, to make survival possible in a civilized and highly populated world on a finite globe. Because of such interweaving and finiteness it is felt that energy should be considered as a system and therefore the term 'energy systems' is used. The production of energy is only one component of such a system; the handling of energy and the embedding of energy into the global and social complex in terms of ecology, economy, risks and resources are of similar importance. he systems approach to the energy problem needs more explanation. This paper is meant to give an outline of the underlying problems and it is hoped that by so doing the wide range of sometimes confusing voices about energy can be better understood. Such confusion starts already with the term 'energy crisis'. Is there an energy crisis or not? Much future work is required to tackle the problems of energy systems. This paper can only marginally help in that respect. But it is hoped that it will help understand the scope of the

An investigation on the effects of phase change material on material components used for high temperature thermal energy storage system

Science.gov (United States)

Kim, Taeil; Singh, Dileep; Zhao, Weihuan; Yua, Wenhua; France, David M.

2016-05-01

The latent heat thermal energy storage (LHTES) systems for concentrated solar power (CSP) plants with advanced power cycle require high temperature phase change materials (PCMs), Graphite foams with high thermal conductivity to enhance the poor thermal conductivity of PCMs. Brazing of the graphite foams to the structural metals of the LHTES system could be a method to assemble the system and a method to protect the structural metals from the molten salts. In the present study, the LHTES prototype capsules using MgCl2-graphite foam composites were assembled by brazing and welding, and tested to investigate the corrosion attack of the PCM salt on the BNi-4 braze. The microstructural analysis showed that the BNi-4 braze alloy can be used not only for the joining of structure alloy to graphite foams but also for the protecting of structure alloy from the corrosion by PCM.

A review on sustainable construction management strategies for monitoring, diagnosing, and retrofitting the building’s dynamic energy performance: Focused on the operation and maintenance phase

International Nuclear Information System (INIS)

Hong, Taehoon; Koo, Choongwan; Kim, Jimin; Lee, Minhyun; Jeong, Kwangbok

2015-01-01

Highlights: • This study reviews the state-of-the-art in “energy” as well as “building”. • Building’s dynamic energy performance should be managed in the built environments. • This study summarizes recent progress in the building’s dynamic energy performance. • The major phases can be categorized into monitoring, diagnosing, and retrofitting. • This study proposes the specific future development directions and challenges by phase. - Abstract: According to a press release, the building sector accounts for about 40% of the global primary energy consumption. Energy savings can be achieved in the building sector by improving the building’s dynamic energy performance in terms of sustainable construction management in the urban-based built environments (referred to as an “Urban Organism”). This study implements the concept of “dynamic approach” to reflect the unexpected changes in the climate and energy environments as well as in the energy policies and technologies. Research in this area is very significant for the future of the building, energy, and environmental industries around the world. However, there is a lack of studies from the perspective of the dynamic approach and the system integration, and thus, this study is designed to fill the research gap. This study highlights the state-of-the-art in the major phases for a building’s dynamic energy performance (i.e., monitoring, diagnosing, and retrofitting phases), focusing on the operation and maintenance phase. This study covers a wide range of research works and provides various illustrative examples of the monitoring, diagnosing, and retrofitting of a building’s dynamic energy performance. Finally, this study proposes the specific future developments and challenges by phase and suggests the future direction of system integration for the development of a carbon-integrated management system as a large complex system. It is expected that researchers and practitioners can

Wind energy systems

Science.gov (United States)

Stewart, H. J.

1978-01-01

A discussion on wind energy systems involved with the DOE wind energy program is presented. Some of the problems associated with wind energy systems are discussed. The cost, efficiency, and structural design of wind energy systems are analyzed.

Heat transfer characteristics of thermal energy storage of a composite phase change materials: Numerical and experimental investigations

International Nuclear Information System (INIS)

Aadmi, Moussa; Karkri, Mustapha; El Hammouti, Mimoun

2014-01-01

In the present study, phase change materials based on epoxy resin paraffin wax with the melting point 27 °C were used as a new energy storage system. Thermophysical properties and the process of melting of a PCM (phase change material) composite were investigated numerically and experimentally. DSC (differential scanning calorimetry) has been used for measurement of melting enthalpy and determination of PCM heat capacity. The thermophysical properties of the prepared composite have been characterized by using a new transient hot plate apparatus. The results have shown that the most important thermal properties of these composites at the solid and liquid states are like the “apparent” thermal conductivity, the heat storage capacity and the latent heat of fusion. These experimental results have been simulated by using numerical Comsol ® Multiphysiques 4.3 based models with success. The results of the experimental investigation compare favorably with the numerical results and thus serve to validate the numerical approach. - Highlights: • Phase change materials based on paraffin spheres used as new energy storage system. • Thermophysical properties and the melting process of composites were investigated. • All experimental results have been simulated using Comsol ® Multiphysiques. • The ability to store and release the thermal energy were investigated. • A very thin molten PCM (phase change material) exists which is apparently visible in the spheres

High Energy Single Frequency Resonant Amplifier, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — This SBIR phase I project proposes a single frequency high energy resonant amplifier for remote sensing. Current state-of-art technologies can not provide all...

The role of phase change materials for the sustainable energy

Directory of Open Access Journals (Sweden)

Kuta Marta

2016-01-01

Full Text Available Unceasing global economic development leads to continuous increase of energy demand. Considering the limited conventional resources of energy as well as impact on the environment associated with its use, it is important to focus on the rational management of energy resources and on supporting the development of new technologies related to both conventional and renewable energy resources. In a number of cases the use of phase change materials (PCMs turns out to be a reasonable solution. This paper contains a summary of well-studied and known, previously used solutions based on phase change materials as well as novel possibilities, which are under development. It has been decided to investigate this topic due to the wide range of highly effective solutions. The review is focused on selected applications of PCMs for technologies which are designed to improve energy efficiency and on PCMs used in technologies based on renewable energy sources.

An energy stable evolution method for simulating two-phase equilibria of multi-component fluids at constant moles, volume and temperature

KAUST Repository

Kou, Jisheng; Sun, Shuyu; Wang, Xiuhua

2016-01-01

In this paper, we propose an energy-stable evolution method for the calculation of the phase equilibria under given volume, temperature, and moles (VT-flash). An evolution model for describing the dynamics of two-phase fluid system is based on Fick

Energy measurement using a resonator-based time-of-flight system

International Nuclear Information System (INIS)

Pardo, R.C.; Lewis, R.N.; Johnson, K.W.; Clifft, B.

1983-01-01

The resonant time-of-flight system which has been developed has several advantages over other potential approaches. The system is non-interceptive and nondestructive. The beam phase space is preserved. It is non-dispersive. Path length variations are not introduced into the beam transport which would reduce the timing resolution. It has a large signal-to-noise ratio when compared to non-resonant beam pick-up techniques. It provides the means to precisely set the linac energy and, potentially, to control the energy in a feedback loop is desired. It is less expensive than an equivalent magnetic system

System identification on two-phase flow stability

International Nuclear Information System (INIS)

Wu Shaorong; Zhang Youjie; Wang Dazhong; Bo Jinghai; Wang Fei

1996-01-01

The theoretical principle, experimental method and results of interrelation analysis identification for the instability of two-phase flow are described. A completely new concept of test technology and method on two-phase flow stability was developed by using he theory of information science on system stability and system identification for two-phase flow stability in thermo-physics field. Application of this method would make it possible to identify instability boundary of two-phase flow under stable operation conditions of two-phase flow system. The experiment was carried out on the thermohydraulic test system HRTL-5. Using reverse repeated pseudo-random sequences of heating power as input signal sources and flow rate as response function in the test, the two-phase flow stability and stability margin of the natural circulation system are investigated. The effectiveness and feasibility of identifying two-phase flow stability by using this system identification method were experimentally demonstrated. Basic data required for mathematics modeling of two-phase flow and analysis of two-phase flow stability were obtained, which are useful for analyzing, monitoring of the system operation condition, and forecasting of two-phase flow stability in engineering system

Energy-Water System Solutions | Energy Analysis | NREL

Science.gov (United States)

System Solutions Energy-Water System Solutions NREL has been a pioneer in the development of energy -water system solutions that explicitly address and optimize energy-water tradeoffs. NREL has evaluated energy-water system solutions for Department of Defense bases, islands, communities recovering from

Wave energy potential: A forecasting system for the Mediterranean basin

International Nuclear Information System (INIS)

Carillo, Adriana; Sannino, Gianmaria; Lombardi, Emanuele

2015-01-01

ENEA is performing ocean wave modeling activities with the aim of both characterizing the Italian sea energy resource and providing the information necessary for the experimental at sea and operational phases of energy converters. Therefore a forecast system of sea waves and of the associated energy available has been developed and has been operatively running since June 2013. The forecasts are performed over the entire Mediterranean basin and, at a higher resolution, over ten sub-basins around the Italian coasts. The forecast system is here described along with the validation of the wave heights, performed by comparing them with the measurements from satellite sensors. [it

Lessons Learned from the Puerto Rico Battery Energy Storage System

Energy Technology Data Exchange (ETDEWEB)

BOYES, JOHN D.; DE ANA, MINDI FARBER; TORRES, WENCESLANO

1999-09-01

The Puerto Rico Electric Power Authority (PREPA) installed a distributed battery energy storage system in 1994 at a substation near San Juan, Puerto Rico. It was patterned after two other large energy storage systems operated by electric utilities in California and Germany. The U.S. Department of Energy (DOE) Energy Storage Systems Program at Sandia National Laboratories has followed the progress of all stages of the project since its inception. It directly supported the critical battery room cooling system design by conducting laboratory thermal testing of a scale model of the battery under simulated operating conditions. The Puerto Rico facility is at present the largest operating battery storage system in the world and is successfully providing frequency control, voltage regulation, and spinning reserve to the Caribbean island. The system further proved its usefulness to the PREPA network in the fall of 1998 in the aftermath of Hurricane Georges. The owner-operator, PREPA, and the architect/engineer, vendors, and contractors learned many valuable lessons during all phases of project development and operation. In documenting these lessons, this report will help PREPA and other utilities in planning to build large energy storage systems.

Low energy pion-pion phase shifts from chiral perturbation theory

International Nuclear Information System (INIS)

Borges, J. Sa; Barbosa, J. Soares; Oguri, V.

1997-01-01

The low energy pion-pion S- and P- experimental phase-shifts are fitted with chiral perturbation theory (Ch PT) amplitude. The low energy pion-pion S- and P- experimental phase-shifts. The parameters l 1 and l 2 of the one loop corrected amplitude are fixed and the corresponding values of the scattering lengths are calculated. We propose that the present method is the best way to fix Ch P T parameters. The unitarization program of current algebra is also discussed. (author)

Renewable Energy Systems

DEFF Research Database (Denmark)

Lund, Henrik; Mathiesen, Brian Vad; Connolly, David

2014-01-01

on the electricity sector, smart energy systems include the entire energy system in its approach to identifying suitable energy infrastructure designs and operation strategies. The typical smart grid sole focus on the electricity sector often leads to the conclusion that transmission lines, flexible electricity......This paper presents the learning of a series of studies that analyse the problems and perspectives of converting the present energy system into a 100 % renewable energy system using a smart energy systems approach. As opposed to, for instance, the smart grid concept, which takes a sole focus...... are to be found when the electricity sector is combined with the heating and cooling sectors and/or the transportation sector. Moreover, the combination of electricity and gas infrastructures may play an important role in the design of future renewable energy systems. The paper illustrates why electricity smart...

Studies on energy system for an energy-saving society; Sho energy gata shakai ni okeru energy system kento

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-03-01

The system to which new energy technology and energy saving technology were introduced was constructed for case studies of urban areas including core cities and the peripheral areas, and the quantitative analysis was conducted on environmental effects, etc. In the energy supply system model, the following element technologies were all considered: cogeneration system, sewage water heat, river water heat, the photovoltaic power generation, energy storage/heat storage/cold heat storage, adsorption type refrigerator, etc. Also considered were power interchange between clusters, system power buying/power selling, heat interchange or no heat interchange, etc. As a result, it was found that when constructing the energy system which synthetically takes into account thermoelectric ratios, rates of simultaneous loads, ratios of daytime/nighttime in the energy supply and demand in the urban area, the energy saving effect multiplicatively increases, and the energy system using cogeneration and unused energy such as refuse and sewage in the urban area and river water brings an energy saving effect of 32% especially in the concentrated cluster. 83 figs., 45 tabs.

Energy landscape for martensitic phase transformation in shape memory NiTi

International Nuclear Information System (INIS)

Kibey, S.; Sehitoglu, H.; Johnson, D.D.

2009-01-01

First-principles calculations are presented for parent B2 phase and martensitic B19 and B19' phases in NiTi. The results indicate that both B19 and B19' are energetically more stable than the parent B2 phase. By means of ab initio density functional theory, the complete distortion-shuffle energy landscape associated with B2 → B19 transformation in NiTi is then determined. In addition to accounting for the Bain-type deformation through the Cauchy-Born rule, the study explicitly accounts for the shuffle displacements experienced by the internal ions in NiTi. The energy landscape allows the energy barrier associated with the B2 → B19 transformation pathway to be identified. The results indicate that a barrier of 0.48 mRyd atom -1 (relative to the B2 phase) must be overcome to transform the parent B2 NiTi to orthorhombic B19 martensite

Experimental Studies of Phase Change and Microencapsulated Phase Change Materials in a Cold Storage/Transportation System with Solar Driven Cooling Cycle

Directory of Open Access Journals (Sweden)

Lin Zheng

2017-11-01

Full Text Available The paper presents the different properties of phase change material (PCM and Microencapsulated phase change material (MEPCM employed to cold storage/transportation system with a solar-driven cooling cycle. Differential Scanning Calorimeter (DSC tests have been performed to analyze the materials enthalpy, melting temperature range, and temperature range of solidification. KD2 Pro is used to test the thermal conductivities of phase change materials slurry and the results were used to compare the materials heat transfer performance. The slurry flow characteristics of MEPCM slurry also have been tested. Furthermore, in order to analyze the improvement effect on stability, the stability of MEPCM slurry with different surfactants have been tested. The researches of the PCM and MEPCM thermal properties revealed a more prospective application for phase change materials in energy storage/transportation systems. The study aims to find the most suitable chilling medium to further optimize the design of the cold storage/transportation systems with solar driven cooling cycles.

Energy saving synergies in national energy systems

DEFF Research Database (Denmark)

Thellufsen, Jakob Zinck; Lund, Henrik

2015-01-01

In the transition towards a 100% renewable energy system, energy savings are essential. The possibility of energy savings through conservation or efficiency increases can be identified in, for instance, the heating and electricity sectors, in industry, and in transport. Several studies point...... to various optimal levels of savings in the different sectors of the energy system. However, these studies do not investigate the idea of energy savings being system dependent. This paper argues that such system dependency is critical to understand, as it does not make sense to analyse an energy saving...... without taking into account the actual benefit of the saving in relation to the energy system. The study therefore identifies a need to understand how saving methods may interact with each other and the system in which they are conducted. By using energy system analysis to do hourly simulation...

Energy measurement using a resonator based time-of-flight system

International Nuclear Information System (INIS)

Pardo, R.C.; Clifft, B.; Johnson, K.W.; Lewis, R.N.

1983-01-01

A resonant pick-up time-of-flight system has been developed for the precise measurement of beam energy at the Argonne Tandem-Linac Accelerator System (ATLAS). The excellent timing characteristics available with ATLAS beams make it desirable to design the beam transport system to be isochronous. The advantages of the resonant time-of-flight system over other energy analysis systems such as the dispersive magnet system are numerous. The system is non-interceptive and non-destructive and preserves the beam phase space. It is non-dispersive. Path length variations are not introduced into the beam which would reduce the timing resolution. It has a large signal-to-noise ratio when compared to non-resonant beam pick-up techniques. It provides the means to precisely set the linac energy and potentially to control the energy in a feedback loop. Finally, the resonant pick-up time-of-flight system is less expensive than an equivalent magnetic system. It consists of two beam-excited resonators, associated electronics to decode the information, a computer interface to the linac PDP 11/34 control computer, and software to analyze the information and deduce the measured beam energy. This report describes the system and its components and gives a schematic overview

Phase-Change Thermal Energy Storage

Science.gov (United States)

1989-11-01

The goal of this program is to advance the engineering and scientific understanding of solar thermal technology and to establish the technology base from which private industry can develop solar thermal power production options for introduction into the competitive energy market. Solar thermal technology concentrates the solar flux using tracking mirrors or lenses onto a receiver where the solar energy is absorbed as heat and converted into electricity or incorporated into products as process heat. The two primary solar thermal technologies, central receivers and distributed receivers, employ various point and line-focus optics to concentrate sunlight. Current central receiver systems use fields of heliostats (two-axes tracking mirrors) to focus the sun's radiant energy onto a single, tower-mounted receiver. Point focus concentrators up to 17 meters in diameter track the sun in two axes and use parabolic dish mirrors or Fresnel lenses to focus radiant energy onto a receiver. Troughs and bowls are line-focus tracking reflectors that concentrate sunlight onto receiver tubes along their focal lines. Concentrating collector modules can be used alone or in a multimodule system. The concentrated radiant energy absorbed by the solar thermal receiver is transported to the conversion process by a circulating working fluid. Receiver temperatures range from 100 C in low-temperature troughs to over 1500 C in dish and central receiver systems.

THERMAL CHARACTERISTICS OF PHASE CHANGE MATERIAL USED AS THERMAL STORAGE SYSTEM BY USING SOLAR ENERGY

Directory of Open Access Journals (Sweden)

Kadhim F. Nasir

2018-01-01

Full Text Available In this paper, the melting processes of phase change material in a shell and tube heat exchanger by using solar thermal energy have been investigated numerically and experimentally. All experimental were outdoor tested at AL-Mussaib city-Babylon-Iraq (Lat 32.5 º North, and long 44.3 º East with N-S collector direction at tilt angle of 32.5 º with the horizontal. The phase change material used in this work is black color Iraqi origin pure Paraffin with amount of 12 kg. In the experimental setup evacuted tube solar collector is employed for melting phase change material in shell regime. Different volume flow rates for the water flow inside the inner tube of heat exchanger namely (200, 300, and 500 LPH for Reynolds number namely (15000, 23000, 38000 respectively were used for each season from August 2016 to January 2017. The numerical investigation involves a three dimension numerical solution of model by a commercial package ANSYS FLUENT 15.0. The boundary conditions of the model that solved by the numerical solution have been taken from the experimental tests. The experimental results indicated that the inner tube inlet and ambient temperatures has a significant effects on the melting process compared with the volume flow rates. Studying phase change material temperature distribution, it is exposed that a melting temperature of the phase change material in summer season needed time of (3-4 hours only, while it needed more time; (14-16 hours in winter season. Increasing solar radiation and ambient temperature reduces the melting time of phase change material. Increasing water temperature difference of inner tube increased the heat gained for phase change material. The results obtained from numerical solution presented the static temperature contours and showed that the temperature distribution of phase change material give good validations with experimental results with percentage deviation of 2.7%. The present experimental results have been

Experimental and numerical investigation of form-stable dodecane/hydrophobic fumed silica composite phase change materials for cold energy storage

International Nuclear Information System (INIS)

Chen, Jiajie; Ling, Ziye; Fang, Xiaoming; Zhang, Zhengguo

2015-01-01

Highlights: • Form-stable dodecane/fumed silica composite for cold storage is prepared. • A suggesting hypothesis that explains infiltration mechanism is proposed. • The performance of the composite phase change material is investigated. • Numerical simulation of system is carried out and results fit well. - Abstract: A kind of form-stable composite phase change materials used for cold thermal energy storage is prepared by absorbing dodecane into the hydrophobic fumed silica. With relatively suitable pore diameter and hydrophobic groups, hydrophobic fumed silica is beneficial to the penetration and infiltration of dodecane and the leakage problem solving. Scanned by electron micrographs and Fourier transformation infrared, the composite phase change material is characterized to be just physical penetration. Besides, the differential scanning calorimeter and thermo gravimetric analysis reveals the high enthalpy, good thermal stability and cycling performance of this composite phase change material. What’s more, Hot-Disk thermal constants analyzer demonstrates that the composite phase change material has low thermal conductivity which is desired in cold storage application. In the experiment, a cold energy storage system is set up and the results from the experiment show that the system has excellent performance of cold storage by incorporating composite phase change material. Apart from that, the experimental data is found to have a great agreement with the numerical simulation which is carried out by using the commercial computational fluid dynamics software FLUENT.

Energy Storage and Smart Energy Systems

DEFF Research Database (Denmark)

Lund, Henrik; Østergaard, Poul Alberg; Connolly, David

2016-01-01

It is often highlighted how the transition to renewable energy supply calls for significant electricity storage. However, one has to move beyond the electricity-only focus and take a holistic energy system view to identify optimal solutions for integrating renewable energy. In this paper......, an integrated cross-sector approach is used to determine the most efficient and least-cost storage options for the entire renewable energy system concluding that the best storage solutions cannot be found through analyses focusing on the individual sub-sectors. Electricity storage is not the optimum solution...... to integrate large inflows of fluctuating renewable energy, since more efficient and cheaper options can be found by integrating the electricity sector with other parts of the energy system and by this creating a Smart Energy System. Nevertheless, this does not imply that electricity storage should...

Feedback Linearization Controller for a Wind Energy Power System

Directory of Open Access Journals (Sweden)

Muthana Alrifai

2016-09-01

Full Text Available This paper deals with the control of a doubly-fed induction generator (DFIG-based variable speed wind turbine power system. A system of eight ordinary differential equations is used to model the wind energy conversion system. The generator has a wound rotor type with back-to-back three-phase power converter bridges between its rotor and the grid; it is modeled using the direct-quadrature rotating reference frame with aligned stator flux. An input-state feedback linearization controller is proposed for the wind energy power system. The controller guarantees that the states of the system track the desired states. Simulation results are presented to validate the proposed control scheme. Moreover, further simulation results are shown to investigate the robustness of the proposed control scheme to changes in some of the parameters of the system.

Phase-field models of microstructure evolution in a system with elastic inhomogeneity and defects

Science.gov (United States)

Hu, Shenyang

In this thesis, the phase-field approach is employed to study the effect of elastic inhomogeneity and structural defects on phase separation kinetics and morphological evolution in bulk and film systems, the precipitation of theta ' phase (Al2Cu) in Al-Cu alloys, and solute strengthening of alloys. By combining the iteration method for calculating the elastic energy and a semi-implicit spectral method for solving the Cahn-Hilliard equation an extremely efficient phase-field model is developed for studying morphological evolution in coherent systems with large elastic inhomogeneity. Spinodal decomposition in a thin film with periodically distributed arrays of interfacial dislocations is simulated. The results show that the periodic stress field associated with the array of interfacial dislocations leads to a directional phase separation and the formation of ordered microstructures. The metastable theta' (Al2Cu) precipitates are one of the primary strengthening precipitates in Al-Cu alloys. They are of a plate-like shape with strong interfacial energy and mobility anisotropies. A phase-field model which can automatically incorporate the thermodynamic and kinetic information from databases is developed. The relationships between phase-field model parameters and material thermodynamic and kinetic properties are established. Systematic simulations of theta' growth in 1D, 2D and 3D are carried out. The growth of a single theta ' precipitate in 1D exactly reproduces the results from analytical solutions. The phase-filed model can serve as a basis for quantitative understanding of the influence of elastic energy, interface energy anisotropy and interface mobility anisotropy on the precipitation of theta' in Al-Cu alloys. Precipitates and solutes are commonly used to strengthen alloys. A phase field model of dislocation dynamics, which employs 12 order parameter fields to describe the dislocation distribution in a single fcc crystal, and one composition field to describe

A compact x-ray system for two-phase flow measurement

Science.gov (United States)

Song, Kyle; Liu, Yang

2018-02-01

In this paper, a compact x-ray densitometry system consisting of a 50 kV, 1 mA x-ray tube and several linear detector arrays is developed for two-phase flow measurement. The system is capable of measuring void fraction and velocity distributions with a spatial resolution of 0.4 mm per pixel and a frequency of 1000 Hz. A novel measurement model has been established for the system which takes account of the energy spectrum of x-ray photons and the beam hardening effect. An improved measurement accuracy has been achieved with this model compared with the conventional log model that has been widely used in the literature. Using this system, void fraction and velocity distributions are measured for a bubbly and a slug flow in a 25.4 mm I.D. air-water two-phase flow test loop. The measured superficial gas velocities show an error within  ±4% when compared with the gas flowmeter for both conditions.

Hydrodynamic modeling of the deconfinement phase transition in heavy-ion collisions in the NICA-FAIR energy domain

International Nuclear Information System (INIS)

Merdeev, A. V.; Satarov, L. M.; Mishustin, I. N.

2011-01-01

We use (3 + 1) dimensional ideal hydrodynamics to describe the space-time evolution of strongly interacting matter created in Au + Au and Pb + Pb collisions. The model is applied for the domain of bombarding energies 1-160 GeV/nucleon which includes future NICA (Dubna) and FAIR (Darmstadt) experiments. Two equations of state are used, the first one corresponding to resonance hadron gas and the second one including the deconfinement phase transition. The initial state is represented by two Lorentz-boosted nuclei. Dynamic trajectories of matter in the central box of the system are analyzed. They can be well represented by a fast shock-wave compression followed by a relatively slow isentropic expansion. The parameters of collective flows and hadronic spectra are calculated under assumption of the isochronous freeze-out. It is shown that the deconfinement phase transition leads to broadening of proton rapidity distributions, increase of elliptic flows, and formation of the directed antiflow in the central rapidity region. These effects are most pronounced at bombarding energies around 10 GeV/nucleon, when the system spends the longest time in the mixed phase. From the comparison with three-fluid calculations we conclude that the transparency effects are not so important in central collisions at NICA-FAIR energies (below 30 GeV/nucleon).

Towards sustainable energy systems: The related role of hydrogen

International Nuclear Information System (INIS)

Hennicke, Peter; Fischedick, Manfred

2006-01-01

The role of hydrogen in long run sustainable energy scenarios for the world and for the case of Germany is analysed, based on key criteria for sustainable energy systems. The possible range of hydrogen within long-term energy scenarios is broad and uncertain depending on assumptions on used primary energy, technology mix, rate of energy efficiency increase and costs degression ('learning effects'). In any case, sustainable energy strategies must give energy efficiency highest priority combined with an accelerated market introduction of renewables ('integrated strategy'). Under these conditions hydrogen will play a major role not before 2030 using natural gas as a bridge to renewable hydrogen. Against the background of an ambitious CO 2 -reduction goal which is under discussion in Germany the potentials for efficiency increase, the necessary structural change of the power plant system (corresponding to the decision to phase out nuclear energy, the transformation of the transportation sector and the market implementation order of renewable energies ('following efficiency guidelines first for electricity generation purposes, than for heat generation and than for the transportation sector')) are analysed based on latest sustainable energy scenarios

Thermodynamic modelling of phase equilibrium for water + poly(Ethylene glycol + salt aqueous two-phase systems

Directory of Open Access Journals (Sweden)

R.A.G. Sé

2002-04-01

Full Text Available The NRTL (nonrandom, two-liquid model, expressed in mass fraction instead of mole fraction, was used to correlate liquid-liquid equilibria for aqueous two-phase polymer-salt solutions. New interaction energy parameters for this model were determined using reported data on the water + poly(ethylene glycol + salt systems, with different molecular masses for PEG and the salts potassium phosphate, sodium sulfate, sodium carbonate and magnesium sulfate. The correlation of liquid-liquid equilibrium is quite satisfactory.

UTILITY ADVANCED TURBINE SYSTEMS (ATS) TECHNOLOGY READINESS TESTING: PHASE 3R

Energy Technology Data Exchange (ETDEWEB)

None

1999-09-01

The overall objective of the Advanced Turbine System (ATS) Phase 3 Cooperative Agreement between GE and the US Department of Energy (DOE) is the development of the GE 7H and 9H combined cycle power systems. The major effort will be expended on detail design. Validation of critical components and technologies will be performed, including: hot gas path component testing, sub-scale compressor testing, steam purity test trials, and rotational heat transfer confirmation testing. Processes will be developed to support the manufacture of the first system, which was to have been sited and operated in Phase 4 but will now be sited and operated commercially by GE. This change has resulted from DOE's request to GE for deletion of Phase 4 in favor of a restructured Phase 3 (as Phase 3R) to include full speed, no load (FSNL) testing of the 7H gas turbine. Technology enhancements that are not required for the first machine design but will be critical for future ATS advances in performance, reliability, and costs will be initiated. Long-term tests of materials to confirm design life predictions will continue. A schematic of the GE H machine is shown. This report summarizes work accomplished in 2Q99.

Electrical system for pulse-width modulated control of a power inverter using phase-shifted carrier signals and related operating methods

Science.gov (United States)

Welchko, Brian A [Torrance, CA

2012-02-14

Systems and methods are provided for pulse-width modulated control of power inverter using phase-shifted carrier signals. An electrical system comprises an energy source and a motor. The motor has a first set of windings and a second set of windings, which are electrically isolated from each other. An inverter module is coupled between the energy source and the motor and comprises a first set of phase legs coupled to the first set of windings and a second set of phase legs coupled to the second set of windings. A controller is coupled to the inverter module and is configured to achieve a desired power flow between the energy source and the motor by modulating the first set of phase legs using a first carrier signal and modulating the second set of phase legs using a second carrier signal. The second carrier signal is phase-shifted relative to the first carrier signal.

Exploring the QCD Phase Structure with Beam Energy Scan in Heavy-ion Collisions

Energy Technology Data Exchange (ETDEWEB)

Luo, Xiaofeng, E-mail: xfluo@mail.ccnu.edu.cn

2016-12-15

Beam energy scan programs in heavy-ion collisions aim to explore the QCD phase structure at high baryon density. Sensitive observables are applied to probe the signatures of the QCD phase transition and critical point in heavy-ion collisions at RHIC and SPS. Intriguing structures, such as dip, peak and oscillation, have been observed in the energy dependence of various observables. In this paper, an overview is given and corresponding physics implications will be discussed for the experimental highlights from the beam energy scan programs at the STAR, PHENIX and NA61/SHINE experiments. Furthermore, the beam energy scan phase II at RHIC (2019–2020) and other future experimental facilities for studying the physics at low energies will be also discussed.

Effect of multiple phase change materials (PCMs) slab configurations on thermal energy storage

International Nuclear Information System (INIS)

Shaikh, Shadab; Lafdi, Khalid

2006-01-01

The present work involves the use of a two dimensional control volume based numerical method to conduct a study of a combined convection-diffusion phase change heat transfer process in varied configurations of composite PCM slabs. Simulations were conducted to investigate the impact of using different configurations of multiple PCM slabs arrangements with different melting temperatures, thermophysical properties and varied sets of boundary conditions on the total energy stored as compared to using a single PCM slab. The degree of enhancement of the energy storage has been shown in terms of the total energy stored rate. The numerical results from the parametric study indicated that the total energy charged rate can be significantly enhanced by using composite PCMs as compared to the single PCM. This enhancement in the energy storage can be of great importance to improve the thermal performance of latent thermal storage systems

Heat-pump-centered integrated community energy systems. System development, Consolidated Natural Gas Service Company, interim report

Energy Technology Data Exchange (ETDEWEB)

Tison, R.R.; Baker, N.R.; Yudow, B.D.; Sala, D.L.; Donakowski, T.D.; Swenson, P.F.

1979-08-01

Heat-pump-centered integrated community energy systems are energy systems for communities that provide heating, cooling, and/or other thermal energy services through the use of heat pumps. Since heat pumps primarily transfer energy from existing and otherwise probably unused sources, rather than convert it from electrical or chemical to thermal form, HP-ICES offer a significant potential for energy savings. Results of the System Development Phase of the HP-ICES Project are given. The heat-actuated (gas) heat-pump incorporated into this HP-ICES concept is under current development and demonstration. The concurrent program was redirected in September 1977 toward large-tonnage applications; it is currently focusing on 60- to 400-ton built-up systems for multi-zone applications. This study evaluates the performance of a HAHP-ICES as applied to a community of residential and commercial buildings. To permit a general assessment of the concept in non-site-specific terms, the sensitivity of the system's performance and economics to climate, community size, utility rate structures, and economic assumptions is explored. (MCW)

Energy systems security

CERN Document Server

Voeller, John G

2014-01-01

Energy Systems Security features articles from the Wiley Handbook of Science and Technology for Homeland Security covering topics related to electricity transmission grids and their protection, risk assessment of energy systems, analysis of interdependent energy networks. Methods to manage electricity transmission disturbances so as to avoid blackouts are discussed, and self-healing energy system and a nano-enabled power source are presented.

Defining climate change scenario characteristics with a phase space of cumulative primary energy and carbon intensity

Science.gov (United States)

Ritchie, Justin; Dowlatabadi, Hadi

2018-02-01

Climate change modeling relies on projections of future greenhouse gas emissions and other phenomena leading to changes in planetary radiative forcing. Scenarios of socio-technical development consistent with end-of-century forcing levels are commonly produced by integrated assessment models. However, outlooks for forcing from fossil energy combustion can also be presented and defined in terms of two essential components: total energy use this century and the carbon intensity of that energy. This formulation allows a phase space diagram to succinctly describe a broad range of possible outcomes for carbon emissions from the future energy system. In the following paper, we demonstrate this phase space method with the Representative Concentration Pathways (RCPs) as used in the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5). The resulting RCP phase space is applied to map IPCC Working Group III (WGIII) reference case ‘no policy’ scenarios. Once these scenarios are described as coordinates in the phase space, data mining techniques can readily distill their core features. Accordingly, we conduct a k-means cluster analysis to distinguish the shared outlooks of these scenarios for oil, gas and coal resource use. As a whole, the AR5 database depicts a transition toward re-carbonization, where a world without climate policy inevitably leads to an energy supply with increasing carbon intensity. This orientation runs counter to the experienced ‘dynamics as usual’ of gradual decarbonization, suggesting climate change targets outlined in the Paris Accord are more readily achievable than projected to date.

Experimental investigation of two-stage thermoelectric generator system integrated with phase change materials

DEFF Research Database (Denmark)

Ahmadi Atouei, Saeed; Ranjbar, Ali Akbar; Rezaniakolaei, Alireza

2017-01-01

this amount of voltage just for 2100 s. Therefore, the proposed design makes TEG systems more suitable for wireless sensor applications when the heat source does not provide steady thermal energy. In this study, four different patterns of thermal power applied to the TTEG system are considered. These patterns...... experimentally. In the first stage, a TEG module installed between a phase change material (PCM) heat sink, as cooling system, and an electrical heater, as the heat source. Because of the inherent characteristics of PCMs to save the thermal energy as latent heat, the PCM heat sink is used as the heat source...

Energy Storage and Smart Energy Systems

Directory of Open Access Journals (Sweden)

Poul Alberg Østergaard

2016-12-01

Full Text Available It is often highlighted how the transition to renewable energy supply calls for significant electricity storage. However, one has to move beyond the electricity-only focus and take a holistic energy system view to identify optimal solutions for integrating renewable energy. In this paper, an integrated cross-sector approach is used to determine the most efficient and least-cost storage options for the entire renewable energy system concluding that the best storage solutions cannot be found through analyses focusing on the individual sub-sectors. Electricity storage is not the optimum solution to integrate large inflows of fluctuating renewable energy, since more efficient and cheaper options can be found by integrating the electricity sector with other parts of the energy system and by this creating a Smart Energy System. Nevertheless, this does not imply that electricity storage should be disregarded but that it will be needed for other purposes in the future.

Energy savings potential from energy-conserving irrigation systems

Energy Technology Data Exchange (ETDEWEB)

Wilfert, G.L.; Patton, W.P.; Harrer, B.J.; Clark, M.A.

1982-11-01

This report systematically compares, within a consistent framework, the technical and economic characteristics of energy-conserving irrigation systems with those of conventional irrigation systems and to determine total energy savings. Levelized annual costs of owning and operating both energy-conserving and conventional irrigation systems have been developed and compared for all 17 states to account for the differences in energy costs and irrigation conditions in each state. Market penetration of energy-conserving systems is assessed for those systems having lower levelized annual costs than conventional systems performing the same function. Annual energy savings were computed by matching the energy savings per system with an assumed maximum market penetration of 100 percent in those markets where the levelized annual costs of energy-conserving systems are lower than the levelized annual costs of conventional systems.

21st century's energy: hydrogen energy system

International Nuclear Information System (INIS)

Veziroglu, T. N.

2007-01-01

Fossil fuels (i.e., petroleum, natural gas and coal), which meet most of the world's energy demand today, are being depleted fast. Also, their combustion products are causing the global problems, such as the greenhouse effect, ozone layer depletion, acid rains and pollution, which are posing great danger for our environment and eventually for the life in our planet. Many engineers and scientists agree that the solution to these global problems would be to replace the existing fossil fuel system by the Hydrogen Energy System. Hydrogen is a very efficient and clean fuel. Its combustion will produce no greenhouse gases, no ozone layer depleting chemicals, little or no acid rain ingredients and pollution. Hydrogen, produced from renewable energy (e.g., solar) sources, would result in a permanent energy system, which we would never have to change. However, there are other energy systems proposed for the post-petroleum era, such as a synthetic fossil fuel system. In this system, synthetic gasoline and synthetic natural gas will be produced using abundant deposits of coal. In a way, this will ensure the continuation of the present fossil fuel system. The two possible energy systems for the post-fossil fuel era (i.e., the solar hydrogen energy system and the synthetic fossil fuel system) are compared with the present fossil fuel system by taking into consideration production costs, environmental damages and utilization efficiencies. The results indicate that the solar hydrogen energy system is the best energy system to ascertain a sustainable future, and it should replace the fossil fuel system before the end of the 21st Century

21st Century's energy: Hydrogen energy system

International Nuclear Information System (INIS)

Veziroglu, T. Nejat; Sahin, Suemer

2008-01-01

Fossil fuels (i.e., petroleum, natural gas and coal), which meet most of the world's energy demand today, are being depleted fast. Also, their combustion products are causing the global problems, such as the greenhouse effect, ozone layer depletion, acid rains and pollution, which are posing great danger for our environment and eventually for the life in our planet. Many engineers and scientists agree that the solution to these global problems would be to replace the existing fossil fuel system by the hydrogen energy system. Hydrogen is a very efficient and clean fuel. Its combustion will produce no greenhouse gases, no ozone layer depleting chemicals, little or no acid rain ingredients and pollution. Hydrogen, produced from renewable energy (e.g., solar) sources, would result in a permanent energy system, which we would never have to change. However, there are other energy systems proposed for the post-petroleum era, such as a synthetic fossil fuel system. In this system, synthetic gasoline and synthetic natural gas will be produced using abundant deposits of coal. In a way, this will ensure the continuation of the present fossil fuel system. The two possible energy systems for the post-fossil fuel era (i.e., the solar-hydrogen energy system and the synthetic fossil fuel system) are compared with the present fossil fuel system by taking into consideration production costs, environmental damages and utilization efficiencies. The results indicate that the solar-hydrogen energy system is the best energy system to ascertain a sustainable future, and it should replace the fossil fuel system before the end of the 21st century

Single phase inverter for a three phase power generation and distribution system

Science.gov (United States)

Lindena, S. J.

1976-01-01

A breadboard design of a single-phase inverter with sinusoidal output voltage for a three-phase power generation and distribution system was developed. The three-phase system consists of three single-phase inverters, whose output voltages are connected in a delta configuration. Upon failure of one inverter the two remaining inverters will continue to deliver three-phase power. Parallel redundancy as offered by two three-phase inverters is substituted by one three-phase inverter assembly with high savings in volume, weight, components count and complexity, and a considerable increase in reliability. The following requirements must be met: (1) Each single-phase, current-fed inverter must be capable of being synchronized to a three-phase reference system such that its output voltage remains phaselocked to its respective reference voltage. (2) Each single-phase, current-fed inverter must be capable of accepting leading and lagging power factors over a range from -0.7 through 1 to +0.7.

Development of Phase Lock Loop System for Synchronisation of a Hybrid System with the Grid

Directory of Open Access Journals (Sweden)

A. S. Abubakar

2016-06-01

Full Text Available Phase locked loop (PLL is an important part of the control unit of the grid connected power converter. The method of zero crossing detection (ZCD does not produce accurate phase information when grid is non-ideal. In this work, a synchronous reference frame (SRF PLL method to obtain accurate phase information when the grid voltages are unbalanced is proposed. The performances of the PLL have been verified for ideal and abnormal grid conditions such as unbalance, voltage sag, faults condition etc. Based on the results obtained, the developed PLL gives better fault ride when unbalances in the three phase input signals are overall handled well by the PLL system as it locks the two signal back within the first cycle. It also overcomes a phase jump after 5 milli-seconds from the time the fault was introduced and performs better tracking of the grid voltage and that of the renewable energy source.

Development of Phase Lock Loop System for Synchronisation of a Hybrid System with the Grid

Directory of Open Access Journals (Sweden)

A. S. Abubakar

2016-12-01

Full Text Available Phase locked loop (PLL is an important part of the control unit of the grid connected power converter. The method of zero crossing detection (ZCD does not produce accurate phase information when grid is non-ideal. In this work, a synchronous reference frame (SRF PLL method to obtain accurate phase information when the grid voltages are unbalanced is proposed. The performances of the PLL have been verified for ideal and abnormal grid conditions such as unbalance, voltage sag, faults condition etc. Based on the results obtained, the developed PLL gives better fault ride when unbalances in the three phase input signals are overall handled well by the PLL system as it locks the two signal back within the first cycle. It also overcomes a phase jump after 5 milli-seconds from the time the fault was introduced and performs better tracking of the grid voltage and that of the renewable energy source.

Promoting energy-saving and environmentally friendly generation dispatching model in China: Phase development and case studies

International Nuclear Information System (INIS)

Ding, Yi; Yang, Hongliang

2013-01-01

Energy saving and environmental protection are important conditions for the sustainable development of Chinese economy. However current widely used generation scheduling model based on predefined production quota and tariff results in heavy energy consumption and severe environment pollution. From 2007, as concerns over energy shortage and environmental pollution, the Chinese authorities introduced the implementation of energy-saving generation dispatching model, which is an important approach to facilitating energy-saving and reduction of pollutant emission. The objective of implementing energy-saving generation dispatching model is to prioritize the use of renewable energy resources and new power plants with high efficiency without compromising power system security and reliability. This paper analyzes the necessity and feasibility of implementing energy-efficient and environmentally friendly generation scheduling models in China. The institutional and technical barriers impeding the implementation of energy-saving generation dispatching model are identified. The development of advanced energy-saving generation scheduling models towards competitive market models and phased planning programs are emphasized in this paper. The effectiveness and experience of provinces piloted energy-saving generation dispatching projects are also discussed. - Highlights: ► Introducing problems of current power generation scheduling model in China. ► Discussing necessity of implementing ESGD model and corresponding barriers. ► Proposing phased planning programs for developing ESGD models. ► Discussing the effectiveness and experience of provinces piloted ESGD projects

Design and Implementation of Geothermal Energy Systems at West Chester University

Energy Technology Data Exchange (ETDEWEB)

Cuprak, Greg [West Chester Univ. of Pennsylvania, PA (United States)

2016-11-02

West Chester University has launched a comprehensive transformation of its campus heating and cooling systems from traditional fossil fuels (coal, oil and natural gas) to geothermal. This change will significantly decrease the institution’s carbon footprint and serve as a national model for green campus efforts. The institution has designed a phased series of projects to build a district geo-exchange system with shared well fields, central pumping station and distribution piping to provide the geo-exchange water to campus buildings as their internal building HVAC systems is changed to be able to use the geo-exchange water. This project addresses the US Department of Energy Office of Energy Efficiency and Renewable Energy (EERE) goal to invest in clean energy technologies that strengthen the economy, protect the environment, and reduce dependence on foreign oil. In addition, this project advances EERE’s efforts to establish geothermal energy as an economically competitive contributor to the US energy supply.

Design and Implementation of Geothermal Energy Systems at West Chester University

Energy Technology Data Exchange (ETDEWEB)

Lewis, James [West Chester Univ., West Chester (PA)

2016-08-05

West Chester University has launched a comprehensive transformation of its campus heating and cooling systems from traditional fossil fuels to geothermal. This change will significantly decrease the institution's carbon footprint and serve as a national model for green campus efforts. The institution has designed a phased series of projects to build a district geo-exchange system with shared well fields, central pumping station and distribution piping to provide the geo-exchange water to campus buildings as their internal building HVAC systems are changed to be able to use the geo-exchange water. This project addresses the US Department of Energy Office of Energy Efficiency and Renewable Energy (EERE) goal to invest in clean energy technologies that strengthen the economy, protect the environment, and reduce dependence on foreign oil. In addition, this project advances EERE's efforts to establish geothermal energy as an economically competitive contributor to the US energy supply.

Energy content of stormtime ring current from phase space mapping simulations

International Nuclear Information System (INIS)

Chen, M.W.; Schulz, M.; Lyons, L.R.

1993-01-01

The authors perform a model study to account for the increase in energy content of the trapped-particle population which occurs during the main phase of major geomagnetic storms. They consider stormtime particle transport in the equatorial region of the magnetosphere. They start with a phase space distribution of the ring current before the storm, created by a steady state transport model. They then use a previously developed guiding center particle simulation to map the stormtime ring current phase space, following Liouville's theorem. This model is able to account for the ten to twenty fold increase in energy content of magnetospheric ions during the storm

Modeling and Simulation for an 8 kW Three-Phase Grid-Connected Photo-Voltaic Power System

Science.gov (United States)

Cen, Zhaohui

2017-09-01

Gird-connected Photo-Voltaic (PV) systems rated as 5-10 kW level have advantages of scalability and energy-saving, so they are very typical for small-scale household solar applications. In this paper, an 8 kW three-phase grid-connected PV system model is proposed and studied. In this high-fidelity model, some basic PV system components such as solar panels, DC-DC converters, DC-AC inverters and three-phase utility grids are mathematically modelled and organized as a complete simulation model. Also, an overall power controller with Maximum Power Point Control (MPPT) is proposed to achieve both high-efficiency for solar energy harvesting and grid-connection stability. Finally, simulation results demonstrate the effectiveness of the PV system model and the proposed controller, and power quality issues are discussed.

Modeling and Simulation for an 8 kW Three-Phase Grid-Connected Photo-Voltaic Power System

Directory of Open Access Journals (Sweden)

Cen Zhaohui

2017-09-01

Full Text Available Gird-connected Photo-Voltaic (PV systems rated as 5-10 kW level have advantages of scalability and energy-saving, so they are very typical for small-scale household solar applications. In this paper, an 8 kW three-phase grid-connected PV system model is proposed and studied. In this high-fidelity model, some basic PV system components such as solar panels, DC-DC converters, DC-AC inverters and three-phase utility grids are mathematically modelled and organized as a complete simulation model. Also, an overall power controller with Maximum Power Point Control (MPPT is proposed to achieve both high-efficiency for solar energy harvesting and grid-connection stability. Finally, simulation results demonstrate the effectiveness of the PV system model and the proposed controller, and power quality issues are discussed.

Ocean thermal energy conversion power system development-I. Phase I. Preliminary design report. Volume 1. Final report

Energy Technology Data Exchange (ETDEWEB)

1978-12-18

The results of a conceptual and preliminary design study of Ocean Thermal Energy Conversion (OTEC) closed loop ammonia power system modules performed by Lockheed Missiles and Space Company, Inc. (LMSC) are presented. This design study is the second of 3 tasks in Phase I of the Power System Development-I Project. The Task 2 objectives were to develop: 1) conceptual designs for a 40 to 50-MW(e) closed cycle ammonia commercial plant size power module whose heat exchangers are immersed in seawater and whose ancillary equipments are in a shirt sleeve environment; preliminary designs for a modular application power system sized at 10-MW(e) whose design, construction and material selection is analogous to the 50 MW(e) module, except that titanium tubes are to be used in the heat exchangers; and 3) preliminary designs for heat exchanger test articles (evaporator and condenser) representative of the 50-MW(e) heat exchangers using aluminum alloy, suitable for seawater service, for testing on OTEC-1. The reference ocean platform was specified by DOE as a surface vessel with the heat exchanger immersed in seawater to a design depth of 0 to 20 ft measured from the top of the heat exchanger. For the 50-MW(e) module, the OTEC 400-MW(e) Plant Ship, defined in the Platform Configuration and Integration study, was used as the reference platform. System design, performance, and cost are presented. (WHK)

Energy Barriers and Hysteresis in Martensitic Phase Transformations

Science.gov (United States)

2008-08-01

glacial acetic acid (CH3COOH) and 10-15% perchloric acid (HCLO4) by volume, the cathode was stainless steel , the anode was stainless steel or Ti, the...Submitted to Acta Materialia Energy barriers and hysteresis in martensitic phase transformations Zhiyong Zhang, Richard D. James and Stefan Müller...hysteresis based on the growth from a small scale of fully developed austenite martensite needles. In this theory the energy of the transition layer plays a

Microcanonical thermodynamics and statistical fragmentation of dissipative systems. The topological structure of the N-body phase space

Science.gov (United States)

Gross, D. H. E.

1997-01-01

This review is addressed to colleagues working in different fields of physics who are interested in the concepts of microcanonical thermodynamics, its relation and contrast to ordinary, canonical or grandcanonical thermodynamics, and to get a first taste of the wide area of new applications of thermodynamical concepts like hot nuclei, hot atomic clusters and gravitating systems. Microcanonical thermodynamics describes how the volume of the N-body phase space depends on the globally conserved quantities like energy, angular momentum, mass, charge, etc. Due to these constraints the microcanonical ensemble can behave quite differently from the conventional, canonical or grandcanonical ensemble in many important physical systems. Microcanonical systems become inhomogeneous at first-order phase transitions, or with rising energy, or with external or internal long-range forces like Coulomb, centrifugal or gravitational forces. Thus, fragmentation of the system into a spatially inhomogeneous distribution of various regions of different densities and/or of different phases is a genuine characteristic of the microcanonical ensemble. In these cases which are realized by the majority of realistic systems in nature, the microcanonical approach is the natural statistical description. We investigate this most fundamental form of thermodynamics in four different nontrivial physical cases: (I) Microcanonical phase transitions of first and second order are studied within the Potts model. The total energy per particle is a nonfluctuating order parameter which controls the phase which the system is in. In contrast to the canonical form the microcanonical ensemble allows to tune the system continuously from one phase to the other through the region of coexisting phases by changing the energy smoothly. The configurations of coexisting phases carry important informations about the nature of the phase transition. This is more remarkable as the canonical ensemble is blind against these

Energy Systems Integration News | Energy Systems Integration Facility |

Science.gov (United States)

, utilities can operate more efficiently and profitably. That can increase the use of renewable energy sources challenge to utility companies, grid operators, and other stakeholders involved in wind energy integration recording is available from the July 16 webinar "Smart Grid Research at NREL's Energy Systems

The Cost of Enforcing Building Energy Codes: Phase 1

Energy Technology Data Exchange (ETDEWEB)

Williams, Alison [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Vine, Ed [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Price, Sarah [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sturges, Andrew [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Rosenquist, Greg [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2013-04-01

The purpose of this literature review is to summarize key findings regarding the costs associated with enforcing building energy code compliance—primarily focusing on costs borne by local government. The review takes into consideration over 150 documents that discuss, to some extent, code enforcement. This review emphasizes those documents that specifically focus on costs associated with energy code enforcement. Given the low rates of building energy code compliance that have been reported in existing studies, as well as the many barriers to both energy code compliance and enforcement, this study seeks to identify the costs of initiatives to improve compliance and enforcement. Costs are reported primarily as presented in the original source. Some costs are given on a per home or per building basis, and others are provided for jurisdictions of a certain size. This literature review gives an overview of state-based compliance rates, barriers to code enforcement, and U.S. Department of Energy (DOE) and key stakeholder involvement in improving compliance with building energy codes. In addition, the processes and costs associated with compliance and enforcement of building energy codes are presented. The second phase of this study, which will be presented in a different report, will consist of surveying 34 experts in the building industry at the national and state or local levels in order to obtain additional cost information, building on the findings from the first phase, as well as recommendations for where to most effectively spend money on compliance and enforcement.

Two-phase flow in refrigeration systems

CERN Document Server

Gu, Junjie; Gan, Zhongxue

2013-01-01

Two-Phase Flow in Refrigeration Systems presents recent developments from the authors' extensive research programs on two-phase flow in refrigeration systems. This book covers advanced mass and heat transfer and vapor compression refrigeration systems and shows how the performance of an automotive air-conditioning system is affected through results obtained experimentally and theoretically, specifically with consideration of two-phase flow and oil concentration. The book is ideal for university postgraduate students as a textbook, researchers and professors as an academic reference book, and b

An energy management system for a directly-driven electric scooter

International Nuclear Information System (INIS)

Yang, Yee-Pien; Liu, Jieng-Jang; Hu, Tsung-Hsien

2011-01-01

An energy management system with an electronic gearshift and regenerative braking is presented to improve the gross efficiency and driving range of an electric scooter, driven directly by a four-phase axial-flux DC brushless wheel motor. The integration of stator windings, batteries, ultracapacitors, and a digital controller constitutes an energy management system, which features smooth electronic gear shifting and regenerative braking. The gross efficiency of the experimental scooter is improved in the drivable range by 20% with respect to that without regenerative braking. The battery-to-wheel efficiency was also above 70% for both low- and high-speed gears.

An energy management system for a directly-driven electric scooter

Energy Technology Data Exchange (ETDEWEB)

Yang, Yee-Pien, E-mail: ypyang@ntu.edu.t [Department of Mechanical Engineering, National Taiwan University, No. 1, Roosevelt Road, Section 4, Taipei, Taiwan (China); Liu, Jieng-Jang, E-mail: jjliu@ntu.edu.t [Department of Mechanical Engineering, National Taiwan University, No. 1, Roosevelt Road, Section 4, Taipei, Taiwan (China); Hu, Tsung-Hsien, E-mail: elvishu@artc.org.t [Department of Mechanical Engineering, National Taiwan University, No. 1, Roosevelt Road, Section 4, Taipei, Taiwan (China)

2011-01-15

An energy management system with an electronic gearshift and regenerative braking is presented to improve the gross efficiency and driving range of an electric scooter, driven directly by a four-phase axial-flux DC brushless wheel motor. The integration of stator windings, batteries, ultracapacitors, and a digital controller constitutes an energy management system, which features smooth electronic gear shifting and regenerative braking. The gross efficiency of the experimental scooter is improved in the drivable range by 20% with respect to that without regenerative braking. The battery-to-wheel efficiency was also above 70% for both low- and high-speed gears.

An energy management system for a directly-driven electric scooter

Energy Technology Data Exchange (ETDEWEB)

Yee-Pien Yang; Jieng-Jang Liu; Tsung-Hsien Hu [Department of Mechanical Engineering, National Taiwan University, No. 1, Roosevelt Road, Section 4, Taipei (China)

2011-01-15

An energy management system with an electronic gearshift and regenerative braking is presented to improve the gross efficiency and driving range of an electric scooter, driven directly by a four-phase axial-flux DC brushless wheel motor. The integration of stator windings, batteries, ultracapacitors, and a digital controller constitutes an energy management system, which features smooth electronic gear shifting and regenerative braking. The gross efficiency of the experimental scooter is improved in the drivable range by 20% with respect to that without regenerative braking. The battery-to-wheel efficiency was also above 70% for both low- and high-speed gears. (author)

Energy Systems Integration News - October 2016 | Energy Systems Integration

Science.gov (United States)

Facility | NREL October 2016 Energy Systems Integration News A monthly recap of the latest energy systems integration (ESI) developments at NREL and around the world. Subscribe Archives October Integration Facility's main control room. OMNETRIC Group Demonstrates a Distributed Control Hierarchy for

Thermal energy storage using phase change materials fundamentals and applications

CERN Document Server

Fleischer, Amy S

2015-01-01

This book presents a comprehensive introduction to the use of solid‐liquid phase change materials to store significant amounts of energy in the latent heat of fusion. The proper selection of materials for different applications is covered in detail, as is the use of high conductivity additives to enhance thermal diffusivity. Dr. Fleischer explores how applications of PCMS have expanded over the past 10 years to include the development of high efficiency building materials to reduce heating and cooling needs, smart material design for clothing, portable electronic systems thermal management, solar thermal power plant design and many others. Additional future research directions and challenges are also discussed.

Where is the magnetic energy for the expansion phase of auroral substorms accumulated? 2. The main body, not the magnetotail

Science.gov (United States)

Akasofu, Syun-Ichi

2017-08-01

It is suggested that the magnetosphere tries to stabilize itself by quickly unloading the magnetic energy accumulated within its main body, when the accumulated magnetic energy exceeds a limited amount, which can be identified as the energy for the expansion phase. It is this process which manifests as the impulsive expansion phase, during which auroral arcs advance well beyond the presubstorm latitude in the midnight sector. It was shown in the previous paper that the magnetotail does not have enough magnetic energy for a medium substorm (energy 5 × 1015 J; AE = 1000 nT). In this paper, it is shown that (1) the reason of the short lifetime (1-1.5 h) of the expansion phase is due to the fact that a limited amount of magnetic energy accumulated during the growth phase is dissipated in a period similar to the duration of the growth phase (1-1.5 h); the accumulation rate is similar to the dissipation rate during the expansion phase: (2) when the main body of the magnetosphere accumulates the magnetic energy, it is inflated; β (= (nkT/B2/8π)) even at XGSM = -6 RE becomes close to 1.0 for magnetic energy (2.9 × 1014 J) which is less than the amount consumed by a medium intensity substorm. (3) As a result, the plasma sheet current and thus the magnetosphere are expected to become unstable, unloading the accumulated excess magnetic energy and resulting in current reduction and deflation. (4) The resulting deflation can cause an earthward electric field of 5-50 mV/m, which can generate Bostrom's current system, which is mainly responsible in producing various phenomena of the expansion phase. (5) The large range of substorm intensity (AE = 100-2000 nT) is likely to be due to the location where the energy is accumulated; the closer is the distance to the Earth (XGSM between -10 RE and -4 RE), the more intense the substorm intensity is.

Development of a generalized correlation for phase-velocity measurements obtained from impedance-probe pairs in two-phase flow systems

International Nuclear Information System (INIS)

Hsu, C.T.; Keshock, E.G.; McGill, R.N.

1983-01-01

A flag type electrical impedance probe has been developed at the Oak Ridge National Lab (ORNL) to measure liquid- and vapor-phase velocities in steam-water mixtures flowing through rod bundles. Measurements are made by utilizing the probes in pairs, installed in line, parallel to the flow direction, and extending out into the flow channel. The present study addresses performance difficulties by examining from a fundamental point of view the two-phase flow system which the impedance probes typically operate in. Specifically, the governing equations (continuity, momentum, energy) were formulated for both air-water and steam-water systems, and then subjected to a scaling analysis. The scaling analysis yielded the appropriate dimensionless parameters of significance in both kinds of systems. Additionally, with the aid of experimental data obtained at ORNL, those parameters of significant magnitude were established. As a result, a generalized correlation was developed for liquid and vapor phase velocities that makes it possible to employ the impedance probe velocity measurement technique in a wide variety of test configurations and fluid combinations

Renewable energy and the need for local energy markets

International Nuclear Information System (INIS)

Hvelplund, Frede

2006-01-01

In Denmark, a technological change towards cleaner energy technologies has been developed and implemented since around 1975. This development has had two phases: The first from 1975 until around 1996, when wind power was a niche production that supplied only 3.5% of the electricity consumption and was brought close to cost competitiveness, and the present second phase, in which wind power supplies an increasing share (in 2004 18.6%) of electricity consumption along with combined heat and power plants, which supply around 50% of consumption. Denmark succeeded in overcoming the first phase, and a large green energy technology cluster was established. During the second phase, new difficulties and challenges have arisen, both with regard to local public acceptance and the need for integrating an increasing percentage of fluctuating energy sources into the energy system. In this Phase 2, a new offensive green energy policy should be introduced in order to secure both public and political acceptance. Local markets should be established in order to secure the technical integration of a large proportion of wind power and other fluctuating renewable energy sources into the energy system

Study of Material Compatibility for a Thermal Energy Storage System with Phase Change Material

Directory of Open Access Journals (Sweden)

Songgang Qiu

2018-03-01

Full Text Available The suitability of stainless steel 316L and Inconel 625 for use in a latent heat thermal energy storage (TES system was investigated. A NaCl–NaF eutectic mixture with a melting temperature of 680 °C was used as the phase change material (PCM. Containers were filled with the PCM prior to heating to 750 °C, then examined after 100 and 2500 h of high-temperature exposure by analyzing the material surface and cross-section areas. A small amount of corrosion was present in both samples after 100 h. Neither sample suffered significant damage after 2500 h. The undesirable inter-granular grain boundary attack found in SS316L samples was in the order of 1–2 µm in depth. On Inconel 625 sample surface, an oxide complex formed, resisting material dissolution into the PCM. The surface morphology of tested samples remained largely unchanged after 2500 h, but the corrosion pattern changed from an initially localized corrosion penetration to a more uniform type. After 2500 h, the corrosion depth of Inconel 625 remained at roughly 1–2 µm, indicating that the corrosion rate decelerated. Both materials demonstrated good compatibility with the chosen NaF–NaCl eutectic salt, but the low corrosion activity in Inconel 625 samples shows a performance advantage for long term operation.

The cost of the nuclear energy-turnaround. An early nuclear phase-out and its consequences; Die Kosten der Energiewende. Ein zeitiger Ausstieg aus der Nuklearenergie und seine Folgen

Energy Technology Data Exchange (ETDEWEB)

Baran, Metin

2013-10-01

The booklet on the consequences of an early nuclear phase-out includes a description of the value creation strategy in the electricity market and the basic relations of the electricity price formation and a survey and evaluation of selected studies. The analysis was performed for the following studies: Energy policy scenarios for a nuclear phase-out in Germany; Economic consequences of a nuclear phase-out in Germany; Transformation of the electricity production systems with a forced nuclear phase-out - a contribution on sustainable energy systems following the reactor accident of Fukushima; Cost of a nuclear phase-out until 2022 in Germany and Bavaria.

Phase transitions in finite systems

Energy Technology Data Exchange (ETDEWEB)

Chomaz, Ph. [Grand Accelerateur National d' Ions Lourds (GANIL), DSM-CEA / IN2P3-CNRS, 14 - Caen (France); Gulminelli, F. [Caen Univ., 14 (France). Lab. de Physique Corpusculaire

2002-07-01

In this series of lectures we will first review the general theory of phase transition in the framework of information theory and briefly address some of the well known mean field solutions of three dimensional problems. The theory of phase transitions in finite systems will then be discussed, with a special emphasis to the conceptual problems linked to a thermodynamical description for small, short-lived, open systems as metal clusters and data samples coming from nuclear collisions. The concept of negative heat capacity developed in the early seventies in the context of self-gravitating systems will be reinterpreted in the general framework of convexity anomalies of thermo-statistical potentials. The connection with the distribution of the order parameter will lead us to a definition of first order phase transitions in finite systems based on topology anomalies of the event distribution in the space of observations. Finally a careful study of the thermodynamical limit will provide a bridge with the standard theory of phase transitions and show that in a wide class of physical situations the different statistical ensembles are irreducibly inequivalent. (authors)

Phase transitions in finite systems

International Nuclear Information System (INIS)

Chomaz, Ph.; Gulminelli, F.

2002-01-01

In this series of lectures we will first review the general theory of phase transition in the framework of information theory and briefly address some of the well known mean field solutions of three dimensional problems. The theory of phase transitions in finite systems will then be discussed, with a special emphasis to the conceptual problems linked to a thermodynamical description for small, short-lived, open systems as metal clusters and data samples coming from nuclear collisions. The concept of negative heat capacity developed in the early seventies in the context of self-gravitating systems will be reinterpreted in the general framework of convexity anomalies of thermo-statistical potentials. The connection with the distribution of the order parameter will lead us to a definition of first order phase transitions in finite systems based on topology anomalies of the event distribution in the space of observations. Finally a careful study of the thermodynamical limit will provide a bridge with the standard theory of phase transitions and show that in a wide class of physical situations the different statistical ensembles are irreducibly inequivalent. (authors)

Aerospace Systems Monitor, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Proposal Title: Aerospace Systems Monitor PHASE 1 Technical Abstract: This Phase II STTR project will continue development and commercialization of the Aerospace...

Energy Production System Management - Renewable energy power supply integration with Building Automation System

International Nuclear Information System (INIS)

Figueiredo, Joao; Martins, Joao

2010-01-01

Intelligent buildings, historically and technologically, refers to the integration of four distinctive systems: Building Automation Systems (BAS), Telecommunication Systems, Office Automation Systems and Computer Building Management Systems. The increasing sophisticated BAS has become the 'heart and soul' of modern intelligent buildings. Integrating energy supply and demand elements - often known as Demand-Side Management (DSM) - has became an important energy efficiency policy concept. Nowadays, European countries have diversified their power supplies, reducing the dependence on OPEC, and developing a broader mix of energy sources maximizing the use of renewable energy domestic sources. In this way it makes sense to include a fifth system into the intelligent building group: Energy Production System Management (EPSM). This paper presents a Building Automation System where the Demand-Side Management is fully integrated with the building's Energy Production System, which incorporates a complete set of renewable energy production and storage systems.

Energy Systems Integration News | Energy Systems Integration Facility |

Science.gov (United States)

grids. In terms of paper sessions, NREL ESI researcher Santosh Veda chaired a session on energy Kroposki chaired a session on advanced renewable energy power systems. While Veda, Muljadi, and Kroposki

Power quality analysis of hybrid renewable energy system

Directory of Open Access Journals (Sweden)

Rinchin W. Mosobi

2015-12-01

Full Text Available An hybrid renewable energy sources consisting of solar photovoltaic, wind energy system, and a microhydro system is proposed in this paper. This system is suitable for supplying electricity to isolated locations or remote villages far from the grid supply. The solar photovoltaic system is modeled with two power converters, the first one being a DC-DC converter along with an maximum power point tracking to achieve a regulated DC output voltage and the second one being a DC-AC converter to obtain AC output. The wind energy system is modeled with a wind-turbine prime mover with varying wind speed and fixed pitch angle to drive an self excited induction generator (SEIG. Owing to inherent drooping characteristics of the SEIG, a closed loop turbine input system is incorporated. The microhydro system is modeled with a constant input power to drive an SEIG. The three different sources are integrated through an AC bus and the proposed hybrid system is supplied to R, R-L, and induction motor loads. A static compensator is proposed to improve the load voltage and current profiles; it also mitigates the harmonic contents of the voltage and current. The static synchronous compensator is realized by means of a three-phase IGBT-based current-controlled voltage source inverter with a self-supporting DC bus. The complete system is modeled and simulated using Matlab/Simulink. The simulation results obtained illustrate the feasibility of the proposed system and are found to be satisfactory.

Phase Noise Compensation for OFDM Systems

Science.gov (United States)

Leshem, Amir; Yemini, Michal

2017-11-01

We describe a low complexity method for time domain compensation of phase noise in OFDM systems. We extend existing methods in several respects. First we suggest using the Karhunen-Lo\\'{e}ve representation of the phase noise process to estimate the phase noise. We then derive an improved datadirected choice of basis elements for LS phase noise estimation and present its total least square counterpart problem. The proposed method helps overcome one of the major weaknesses of OFDM systems. We also generalize the time domain phase noise compensation to the multiuser MIMO context. Finally we present simulation results using both simulated and measured phased noise. We quantify the tracking performance in the presence of residual carrier offset.

Energy Budget of Cosmological First-order Phase Transitions

CERN Document Server

Espinosa, Jose R; No, Jose M; Servant, Geraldine

2010-01-01

The study of the hydrodynamics of bubble growth in first-order phase transitions is very relevant for electroweak baryogenesis, as the baryon asymmetry depends sensitively on the bubble wall velocity, and also for predicting the size of the gravity wave signal resulting from bubble collisions, which depends on both the bubble wall velocity and the plasma fluid velocity. We perform such study in different bubble expansion regimes, namely deflagrations, detonations, hybrids (steady states) and runaway solutions (accelerating wall), without relying on a specific particle physics model. We compute the efficiency of the transfer of vacuum energy to the bubble wall and the plasma in all regimes. We clarify the condition determining the runaway regime and stress that in most models of strong first-order phase transitions this will modify expectations for the gravity wave signal. Indeed, in this case, most of the kinetic energy is concentrated in the wall and almost no turbulent fluid motions are expected since the s...

Analysis of three-phase power-supply systems using computer-aided design programs

International Nuclear Information System (INIS)

Oberst, E.F.

1977-01-01

A major concern of every designer of large, three-phase power-supply systems is the protection of system components from overvoltage transients. At present, three computer-aided circuit design programs are available in the Magnetic Fusion Energy (MFE) National Computer Center that can be used to analyze three-phase power systems: MINI SCEPTRE, SPICE I, and SPICE II. These programs have been used at Lawrence Livermore Laboratory (LLL) to analyze the operation of a 200-kV dc, 20-A acceleration power supply for the High Voltage Test Stand. Various overvoltage conditions are simulated and the effectiveness of system protective devices is observed. The simulated overvoltage conditions include such things as circuit breaker openings, pulsed loading, and commutation voltage surges in the rectifiers. These examples are used to illustrate the use of the computer-aided, circuit-design programs discussed in this paper

Total energy calculations for structural phase transformations

International Nuclear Information System (INIS)

Ye, Y.Y.; Chan, C.T.; Ho, K.M.; Harmon, B.N.

1990-01-01

The structural integrity and physical properties of crystalline solids are frequently limited or enhanced by the occurrence of phase transformations. Martensitic transformations involve the collective displacement of atoms from one ordered state to another. Modern methods to determine the microscopic electronic changes as the atoms move are now accurate enough to evaluate the very small energy differences involved. Extensive first principles calculations for the prototypical martensitic transformation from body-centered cubic (bcc) to closepacked 9R structure in sodium metal are described. The minimum energy coordinate or configuration path between the bcc and 9R structures is determined as well as paths to other competing close-packed structures. The energy barriers and important anharmonic interactions are identified and general conclusions drawn. The calculational methods used to solve the Schrodinger equation include pseudopotentials, fast Fourier transforms, efficient matrix diagnonalization, and supercells with many atoms

A semiclassical treatment of correlation energy for nuclear systems

International Nuclear Information System (INIS)

Nielsen, M.

1988-01-01

Starting with the separation of the many-body density operator in two parts, one describing the one-body aspects of the full density and the other containing all dynamic correlations information, the semiclassical approximation for the system correlation energy, was calculated. It is showm that, in this case, the Gaussian Wave Packets Phase Space Representation is more convenient than the Wely-Wigner Rrepresentation for the analysis of the semiclassical correlation energy. Using a phenomenological interaction, the correlation energy to the nuclear matter and some simmetric finite nucleus was calculated. The Fermi Surface Diffusivity, was also calculated. Finally, from the relation between this theory and the pertubation theory, we have done some considerations about the viability on the local densities expansion for energy functionals. (author) [pt

Discovery of a ternary pseudobrookite phase in the earth-abundant Ti-Zn-O system.

Science.gov (United States)

Perry, Nicola H; Stevanovic, Vladan; Lim, Linda Y; Mason, Thomas O

2016-01-28

We combine theory with experiment in searching for "missing", stable materials within the Zn-Ti-O chemical system, leading to the discovery of a new pseudobrookite phase, ZnxTi3-xO5-δ. This ternary system was chosen for (1) technological relevance, (2) earth abundance, and (3) the fact that many compounds in this system are predicted from enthalpies of formation to be borderline stable, suggesting an important role of entropic contributions in their stabilization and making this chemical system a perfect test bed for exploring the limits of theoretical predictions. The initial set of exploratory experimental syntheses, via sintering in evacuated ampoules and quenching, resulted in a single phase ZnxTi3-xO5-δ composition with x ≈ 0.6 and an almost stoichiometric oxygen content, as evaluated by X-ray fluorescence, energy dispersive spectroscopy, thermogravimetric analysis, and X-ray photoelectron spectroscopy. The theoretically calculated lowest energy crystal structure for the closest stoichiometric ZnTi5O10 composition matched that measured experimentally by synchrotron X-ray diffraction (allowing for differences attributable to cation disorder). The measured broad optical absorption, n-type electrical conductivity, and stability in acidic media are comparable to those of other ternary pseudobrookites and Ti-O Magnéli phases, suggesting comparable applicability as a robust electrode or catalyst support in electrochemical devices or water remediation. However, the new phase decomposes upon heating in air as it oxidizes. The success of the present approach to identify a "missing material" in an earth-abundant and applications-rich system suggests that future efforts to experimentally realize and theoretically confirm missing materials in this and similar systems are warranted, both scientifically and technologically.

Characterization of the polymer energy landscape in polymer:fullerene bulk heterojunctions with pure and mixed phases

KAUST Repository

Sweetnam, Sean

2014-10-08

Theoretical and experimental studies suggest that energetic offsets between the charge transport energy levels in different morphological phases of polymer:fullerene bulk heterojunctions may improve charge separation and reduce recombination in polymer solar cells (PSCs). In this work, we use cyclic voltammetry, UV-vis absorption, and ultraviolet photoelectron spectroscopy to characterize hole energy levels in the polymer phases of polymer:fullerene bulk heterojunctions. We observe an energetic offset of up to 150 meV between amorphous and crystalline polymer due to bandgap widening associated primarily with changes in polymer conjugation length. We also observe an energetic offset of up to 350 meV associated with polymer:fullerene intermolecular interactions. The first effect has been widely observed, but the second effect is not always considered despite being larger in magnitude for some systems. These energy level shifts may play a major role in PSC performance and must be thoroughly characterized for a complete understanding of PSC function.

A phase transition in energy-filtered RNA secondary structures

DEFF Research Database (Denmark)

Han, Hillary Siwei; reidys, Christian

2012-01-01

In this paper we study the effect of energy parameters on minimum free energy (mfe) RNA secondary structures. Employing a simplified combinatorial energy model, that is only dependent on the diagram representation and that is not sequence specific, we prove the following dichotomy result. Mfe...... this phase transition from a discrete limit to a central limit distribution and subsequently put our result into the context of quantifying the effect of sparsification of the folding of these respective mfe-structures. We show that the sparsification of realistic mfe-structures leads to a constant time...

Bio energy: Bio energy in the Energy System of the Future

International Nuclear Information System (INIS)

Finden, Per; Soerensen, Heidi; Wilhelmsen, Gunnar

2001-01-01

This is Chapter 7, the final chapter, of the book ''Bio energy - Environment, technique and market''. Its main sections are: (1) Factors leading to changes in the energy systems, (2) The energy systems of the future, globally, (3) The future energy system in Norway and (4) Norwegian energy policy at the crossroads

Phased arrays: A strategy to lower the energy threshold for neutrinos

Directory of Open Access Journals (Sweden)

Wissel Stephanie

2017-01-01

Full Text Available In-ice radio arrays are optimized for detecting the highest energy, cosmogenic neutrinos expected to be produced though cosmic ray interactions with background photons. However, there are two expected populations of high energy neutrinos: the astrophysical flux observed by IceCube (~1 PeV and the cosmogenic flux (~ 1017 eV or 100 PeV. Typical radio arrays employ a noise-riding trigger, which limits their minimum energy threshold based on the background noise temperature of the ice. Phased radio arrays could lower the energy threshold by combining the signals from several channels before triggering, thereby improving the signal-to-noise at the trigger level. Reducing the energy threshold would allow radio experiments to more efficiently overlap with optical Cherenkov neutrino telescopes as well as for more efficient searches for cosmogenic neutrinos. We discuss the proposed technique and prototypical phased arrays deployed in an anechoic chamber and at Greenland’s Summit Station.

Trenton ICES: demonstration of a grid-connected integrated community energy system. Phase II. Volumes 1 and 2. Preliminary design of ICES system and analysis of community ownership

Energy Technology Data Exchange (ETDEWEB)

1978-03-22

Preliminary design and evaluation for the system has been carried out. The findings of this study are: (1) it is technically feasible, utilizing commercially available hardware; (2) under utility ownership and operation, it will not be economically competitive with conventional alternatives for heating and cooling buildings (analysis contained in companion report under separate cover); (3) under utility ownership and operation, no restrictions have been identified that would prevent the project from proceeding; (4) under community ownership, preliminary analysis indicates that thermal energy produced by Trenton ICES will be approximately 12 percent less expensive than thermal energy produced by oil-fired boilers; and (5) a review and update of institutional analyses performed during Phase 2 has identified no factors that would preclude community ownership and operation of the Trenton ICES. The background data produced for the analysis of the Trenton ICES based on utility ownership and operation can, in large part, be used as the bases for a detailed analysis of community ownership.

Modeling and Simulation for an 8 kW Three-Phase Grid-Connected Photo-Voltaic Power System

OpenAIRE

Cen Zhaohui

2017-01-01

Gird-connected Photo-Voltaic (PV) systems rated as 5-10 kW level have advantages of scalability and energy-saving, so they are very typical for small-scale household solar applications. In this paper, an 8 kW three-phase grid-connected PV system model is proposed and studied. In this high-fidelity model, some basic PV system components such as solar panels, DC-DC converters, DC-AC inverters and three-phase utility grids are mathematically modelled and organized as a complete simulation model....

The use of lipids as phase change materials for thermal energy storage

Science.gov (United States)

Phase change materials (PCMs) are substances capable of absorbing and releasing large 2 amounts of thermal energy (heat or cold) as latent heat over constant temperature as they 3 undergo a change in state of matter (phase transition), commonly, between solid and 4 liquid phases. Since the late 194...

Croatian Energy System Defossilization

International Nuclear Information System (INIS)

Potocnik, V.

2013-01-01

Defossilization of an energy system, as primary cause of the actual climate change, means exchange of predominantly imported fossil fuels with climate more convenient energy carriers, facilitating thus the way out of crisis.Overview of the world and Croatian energy system situation is presented as well as the overview of climate change. The most important Croatian energy system defossilization measures-energy efficiency increase, renewable energy inclusion and others - are described.(author)

The German energy policy as a consequence of Fukushima. The scientific discussion between nuclear phase-out and economic growth

International Nuclear Information System (INIS)

Radtke, Joerg

2013-01-01

The book on the German energy policy as a consequence includes the following contributions: The German energy turnaround - scientific contributions. The energy turnaround in Germany - issue of interdisciplinary science. The transformation of the energy systems as social and technical challenge, - on the need of integrating energy research. Transformations and transformation blockades in the German energy system. The German energy turnaround in the context of international best practice. Energy turnaround also in Japan? - The chances of a nuclear phase-out. Possibilities and limits of public participation for the realization of an energy turnaround. Public energy in Germany - a model for participation? A plea for a comprehensive analysis of the energy turnaround in relation to the omnipresent crisis. Challenges and development in the German energy industry - consequences of the increasing percentage of renewable energies on the costs and the security of supply. Research funding and innovation promotion in the area of selected renewable energies. The economic chances of an energy turnaround. The need of appropriate monetary boundary conditions for the energy turnaround and the possibilities of an organization. The human factor in the context of the energy turnaround - environmental-psychological research approaches. The legal contribution to the energy turnaround. Vulnerability and resilience of energy systems. Geography of renewable energies -spatial constraints of a sustainable energy system. Critics and alternatives: The German energy turnaround that is no turnaround.

Energy storage systems having an electrode comprising Li.sub.xS.sub.y

Science.gov (United States)

Xiao, Jie; Zhang, Jiguang; Graff, Gordon L.; Liu, Jun; Wang, Wei; Zheng, Jianming; Xu, Wu; Shao, Yuyan; Yang, Zhenguo

2016-08-02

Improved lithium-sulfur energy storage systems can utilizes Li.sub.xS.sub.y as a component in an electrode of the system. For example, the energy storage system can include a first electrode current collector, a second electrode current collector, and an ion-permeable separator separating the first and second electrode current collectors. A second electrode is arranged between the second electrode current collector and the separator. A first electrode is arranged between the first electrode current collector and the separator and comprises a first condensed-phase fluid comprising Li.sub.xS.sub.y. The energy storage system can be arranged such that the first electrode functions as a positive or a negative electrode.

Low-energy-state dynamics of entanglement for spin systems

International Nuclear Information System (INIS)

Jafari, R.

2010-01-01

We develop the ideas of the quantum renormalization group and quantum information by exploring the low-energy-state dynamics of entanglement resources of a system close to its quantum critical point. We demonstrate that low-energy-state dynamical quantities of one-dimensional magnetic systems can show a quantum phase transition point and show scaling behavior in the vicinity of the transition point. To present our idea, we study the evolution of two spin entanglements in the one-dimensional Ising model in the transverse field. The system is initialized as the so-called thermal ground state of the pure Ising model. We investigate the evolution of the generation of entanglement with increasing magnetic field. We obtain that the derivative of the time at which the entanglement reaches its maximum with respect to the transverse field diverges at the critical point and its scaling behaviors versus the size of the system are the same as the static ground-state entanglement of the system.

Phase equilibria and thermodynamics of the Fe–Al–C system: Critical evaluation, experiment and thermodynamic optimization

International Nuclear Information System (INIS)

Phan, Anh Thu; Paek, Min-Kyu; Kang, Youn-Bae

2014-01-01

In order to provide an efficient tool to design alloy chemistry and processing conditions for high-strength, lightweight steel, an investigation of the Fe–Al–C ternary system was carried out by experimental phase diagram measurement and a CALPHAD thermodynamic analysis. Discrepancies between previously available experimental results and thermodynamic calculations were identified. The Fe–Al sub-binary system was re-optimized in order to obtain an accurate description of the liquid phase, while Gibbs energies of solid phases were mainly taken from a previous thermodynamic modeling. Phase equilibria among face-centered cubic (fcc)/body-centered cubic (bcc)/graphite/κ-carbide/liquid phases in the Fe–Al–C system in the temperature range from 1000 to 1400 °C were obtained by chemical equilibration followed by quenching, and subsequent composition analysis using electron probe microanalysis/inductively coupled plasma spectroscopy. By merging the revised Fe–Al binary description with existing Fe–C and Al–C binary descriptions, a complete thermodynamic description of the Fe–Al–C system was obtained in the present study. The modified quasi-chemical model in the pair approximation was used to model the liquid phase, while solid solutions were modeled using compound energy formalism. A2/B2 order/disorder transition in the bcc phase was taken into account. Compared with previously known experiments/thermodynamic modeling, a better agreement was obtained in the present study, regarding the stable region of fcc and the solidification thermal peak of a ternary alloy near the liquidus temperature. The obtained thermodynamic description also reproduced various types of experimental data in the Fe–Al–C system such as isothermal sections, vertical sections, liquidus projection, etc. The solidification of various steel grades was predicted and discussed

The CEBAF fiber optic phase reference system

International Nuclear Information System (INIS)

Crawford, K.; Simrock, S.; Hovater, C.; Krycuk, A.

1995-01-01

The specified phase stability of the CEBAF RF distribution system is 2.9 degree rms per linac. Stability is achieved through the use of a temperature and pressure regulated coaxial drive line. Purpose of the fiber optic phase reference system is to monitor the relative phase at the beginning and ending of this drive line, between linacs, injector and separator to determine drift due to ambient temperature fluctuations. The system utilizes an Ortel 1310 nm single mode laser driving Sumitumo optical fiber to distribute a reference signal at 1497 MHz. Phase of this reference signal is compared to the 1427 MHz (LO) and the 70 MHz (IF) via a 360 degree phase detector. The detected information is then routed to the CEBAF control system for display with a specified resolution of ±0.2 degree over a 20 degree phase delta

Innovative Business Cases for Energy Storage In a Restructured Electricity Marketplace, A Study for the DOE Energy Storage Systems Program

Energy Technology Data Exchange (ETDEWEB)

IANNUCCI, JOE; EYER, JIM; BUTLER, PAUL C.

2003-02-01

This report describes the second phase of a project entitled ''Innovative Business Cases for Energy Storage in a Restructured Electricity Marketplace''. During part one of the effort, nine ''Stretch Scenarios'' were identified. They represented innovative and potentially significant uses of electric energy storage. Based on their potential to significantly impact the overall energy marketplace, the five most compelling scenarios were identified. From these scenarios, five specific ''Storage Market Opportunities'' (SMOs) were chosen for an in-depth evaluation in this phase. The authors conclude that some combination of the Power Cost Volatility and the T&D Benefits SMOs would be the most compelling for further investigation. Specifically, a combination of benefits (energy, capacity, power quality and reliability enhancement) achievable using energy storage systems for high value T&D applications, in regions with high power cost volatility, makes storage very competitive for about 24 GW and 120 GWh during the years of 2001 and 2010.

A Review of Study on Thermal Energy Transport System by Synthesis and Decomposition Reactions of Methanol

Science.gov (United States)

Liu, Qiusheng; Yabe, Akira; Kajiyama, Shiro; Fukuda, Katsuya

The study on thermal energy transport system by synthesis and decomposition reactions of methanol was reviewed. To promote energy conservation and global environment protection, a two-step liquid-phase methanol synthesis process, which starts with carbonylation of methanol to methyl formate, then followed by the hydrogenolysis of the formate, was studied to recover wasted or unused discharged heat from industrial sources for the thermal energy demands of residential and commercial areas by chemical reactions. The research and development of the system were focused on the following three points. (1) Development of low-temperature decomposition and synthetic catalysts, (2) Development of liquid phase reactor (heat exchanger accompanying chemical reaction), (3) Simulation of the energy transport efficiency of entire system which contains heat recovery and supply sections. As the result of the development of catalyst, promising catalysts which agree with the development purposes for the methyl formate decomposition reaction and the synthetic reaction are being developed though some studies remain for the methanol decomposition and synthetic reactions. In the fundamental development of liquid phase reactor, the solubilities of CO and H2 gases in methanol and methyl formate were measured by the method of total pressure decrease due to absorption under pressures up to 1500kPa and temperatures up to 140°C. The diffusivity of CO gas in methanol was determined by measuring the diameter and solution time of single CO bubbles in methanol. The chemical reaction rate of methanol synthesis by hydrogenolysis of methyl formate was measured using a plate-type of Raney copper catalyst in a reactor with rectangular channel and in an autoclave reactor. The reaction characteristics were investigated by carrying out the experiments at various temperatures, flow rates and at various catalyst development conditions. We focused on the effect of Raney copper catalyst thickness on the liquid-phase

First-order system least squares and the energetic variational approach for two-phase flow

Science.gov (United States)

Adler, J. H.; Brannick, J.; Liu, C.; Manteuffel, T.; Zikatanov, L.

2011-07-01

This paper develops a first-order system least-squares (FOSLS) formulation for equations of two-phase flow. The main goal is to show that this discretization, along with numerical techniques such as nested iteration, algebraic multigrid, and adaptive local refinement, can be used to solve these types of complex fluid flow problems. In addition, from an energetic variational approach, it can be shown that an important quantity to preserve in a given simulation is the energy law. We discuss the energy law and inherent structure for two-phase flow using the Allen-Cahn interface model and indicate how it is related to other complex fluid models, such as magnetohydrodynamics. Finally, we show that, using the FOSLS framework, one can still satisfy the appropriate energy law globally while using well-known numerical techniques.

Analysis of Mechanical Energy Transport on Free-Falling Wedge during Water-Entry Phase

Directory of Open Access Journals (Sweden)

Wen-Hua Wang

2012-01-01

Full Text Available For better discussing and understanding the physical phenomena and body-fluid interaction of water-entry problem, here mechanical-energy transport (wedge, fluid, and each other of water-entry model for free falling wedge is studied by numerical method based on free surface capturing method and Cartesian cut cell mesh. In this method, incompressible Euler equations for a variable density fluid are numerically calculated by the finite volume method. Then artificial compressibility method, dual-time stepping technique, and Roe's approximate Riemann solver are applied in the numerical scheme. Furthermore, the projection method of momentum equations and exact Riemann solution are used to calculate the fluid pressure on solid boundary. On this basis, during water-entry phase of the free-falling wedge, macroscopic energy conversion of overall body-fluid system and microscopic energy transformation in fluid field are analyzed and discussed. Finally, based on test cases, many useful conclusions about mechanical energy transport for water entry problem are made and presented.

Flexible Mode Control of Grid Connected Wind Energy Conversion System Using Wavelet

Directory of Open Access Journals (Sweden)

Bhavna Jain

2015-01-01

Full Text Available Small wind turbine systems offer services to critical loads during grid faults and also connected back to grid in normal condition. The connection of a wind energy conversion system to the grid requires a robust phase locked loop (PLL and continuous monitoring of the grid conditions such as overvoltage, undervoltage, overfrequency, underfrequency, and grid outages. This paper describes a flexible control operation to operate a small wind turbine in both stand-alone mode via planned islanding and grid connected mode as well. In particular, a proper monitoring and control algorithm is required for transition between the modes. A wavelet based energy function is used for detection of grid disturbances as well as recovery of grid so that transition between the modes is made. To obtain good power quality LCL filter is used to reduce ripples. PLL is used for synchronization whenever mode changes from stand-alone to grid connected. Simulation results from a 10 kW wind energy conversion system are included to show the usefulness of the proposed methods. The control method is tested by generated gate pulses for single phase bridge inverter using field programmable gate array (FPGA.

Optimum strategies for nuclear energy system development (method of synthesis)

International Nuclear Information System (INIS)

Belenky, V.Z.

1983-01-01

The problem of optimum long-term development of the nuclear energy system is considered. The optimum strategies (i.e. minimum total uranium consumption) for the transition phase leading to a stationary regime of development are found. For this purpose the author has elaborated a new method of solving linear problems of optimal control which can include jumps in trajectories. The method gives a possibility to fulfil a total synthesis of optimum strategies. A key characteristic of the problem is the productivity function of the nuclear energy system which connects technological system parameters with its growth rate. There are only two types of optimum strategies, according to an increasing or decreasing productivity function. Both cases are illustrated with numerical examples. (orig.) [de

Economical assessment of a wind-hydrogen energy system using WindHyGen registered software

International Nuclear Information System (INIS)

Aguado, Monica; Ayerbe, Elixabete; Garde, Raquel; Rivas, David M.; Azcarate, Cristina; Blanco, Rosa; Mallor, Fermin

2009-01-01

This paper considers the problem of analyzing the economical feasibility of a wind-hydrogen energy storage and transformation system. Energy systems based on certain renewable sources as wind power, have the drawback of random input making them a non-reliable supplier of energy. Regulation of output energy requires the introduction of new equipment with the capacity to store it. We have chosen the hydrogen as an energy storage system due to its versatility. The advantage of these energy storage systems is that the energy can be used (sold) when the demand for energy rises, and needs (prices) therefore are higher. There are two disadvantages: (a) the cost of the new equipment and (b) energy loss due to inefficiencies in the transformation processes. In this research we develop a simulation model to aid in the economic assessment of this type of energy systems, which also integrates an optimization phase to simulate optimal management policies. Finally we analyze a wind-hydrogen farm in order to determine its economical viability compared to current wind farms. (author)

High Efficiency and Low Cost Thermal Energy Storage System

Energy Technology Data Exchange (ETDEWEB)

Sienicki, James J. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Lv, Qiuping [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Moisseytsev, Anton [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Bucknor, Matthew [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division

2017-09-29

BgtL, LLC (BgtL) is focused on developing and commercializing its proprietary compact technology for processes in the energy sector. One such application is a compact high efficiency Thermal Energy Storage (TES) system that utilizes the heat of fusion through phase change between solid and liquid to store and release energy at high temperatures and incorporate state-of-the-art insulation to minimize heat dissipation. BgtL’s TES system would greatly improve the economics of existing nuclear and coal-fired power plants by allowing the power plant to store energy when power prices are low and sell power into the grid when prices are high. Compared to existing battery storage technology, BgtL’s novel thermal energy storage solution can be significantly less costly to acquire and maintain, does not have any waste or environmental emissions, and does not deteriorate over time; it can keep constant efficiency and operates cleanly and safely. BgtL’s engineers are experienced in this field and are able to design and engineer such a system to a specific power plant’s requirements. BgtL also has a strong manufacturing partner to fabricate the system such that it qualifies for an ASME code stamp. BgtL’s vision is to be the leading provider of compact systems for various applications including energy storage. BgtL requests that all technical information about the TES designs be protected as proprietary information. To honor that request, only non-proprietay summaries are included in this report.