Página 1 dos resultados de 1065 itens digitais encontrados em 0.075 segundos

‣ Energy Production System Management – Renewable Energy Power Supply Integration with Building Automation System

Figueiredo, Joao; Martins, Joao
Fonte: Energy Conversion and Management, Elsevier Publicador: Energy Conversion and Management, Elsevier
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
67.7145%
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.

‣ Regulation of the wind power production: contribution of the electric vehicles and other energy storage systems

Mateus, C. B.; Estanqueiro, Ana
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em //2012 Português
Relevância na Pesquisa
77.493745%
The increasing penetration of renewable energy sources (RES) introduces additional difficulties in the design and operation of the power systems, mainly due to the high timevariability of these renewable resources, their non-dispatchability and the poor correlation with load profiles. In order to reduce negative impacts for the power systems while maximizing the penetration of RES - especially in power systems with a high renewable contribution as the Portuguese system - it is necessary to provide the system with means to regulate this highly variable power source that normally already exceeds the load consumption during wet and windy no-load periods.

‣ A constructive technology assessment of stationary energy storage systems: prospective life cycle orientated analysis

Baumann, Manuel
Fonte: IET Publicador: IET
Tipo: Relatório
Publicado em /01/2012 Português
Relevância na Pesquisa
87.98931%
Based on the presentation and discussion at the 3rd Winter School on Technology Assessment, December 2012, Universidade Nova de Lisboa (Portugal), Caparica Campus, PhD programme on Technology Assessment; Environmental concerns over the use of fossil fuels and their resource constraints have increased the interest in generating electric energy from renewable energy sources (RES) to provide a sustainable electricity supply. A main problem of those technologies (wind or solar power generation) is that they are not constant and reliable sources of power. This results inter alia in an increased demand of energy storage technologies. Related stake holders show a big interest in the technical, economic and ecologic aspects of new emerging energy storage systems. This comes especially true for electrochemical energy storage systems as different Li-Ion batteries, Sodium Sulfur or Redox Flow batteries which can be utilized in all grid voltage levels, a wide range of grid applications as well as end user groups (e.g. private households, industry). A prospective and active Constructive Technology Assessment (CTA) can help to minimize potential mismatches, wrong investments, possible social conflicts, and environmental impacts of new energy storage technologies in an early development stage. It is insufficient to exclusively look at the operation phase to assess a technology. Such an approach can lead to misleading interpretations and can furthermore disregard social or ecological impact factors over the whole life cycle. Different energy storage technologies have to be evaluated in a prospective manner with a full integrated sustainability and life cycle approach to form a base for decision making and to support technology developers in order to allow distinctions between more or less sustainable battery technology variations. Therefore CTA is used as a scientific approach using several “neighbouring” engineering orientated disciplines e.g. Life Cycle Analysis (LCA)...

‣ A hybrid solar and chemical looping combustion system for solar thermal energy storage

Jafarian, S.; Arjomandi, M.; Nathan, G.
Fonte: Elsevier Sci Ltd Publicador: Elsevier Sci Ltd
Tipo: Artigo de Revista Científica
Publicado em //2013 Português
Relevância na Pesquisa
77.58964%
A novel hybrid of a solar thermal energy and a chemical looping combustion (CLC) system is proposed here, which employs the oxygen carrier particles in a CLC system to provide diurnal thermal energy storage for concentrated solar thermal energy. In taking advantage of the chemical and sensible energy storage systems that are an inherent part of a CLC system, this hybrid offers potential to achieve cost effective, base load power generation for solar energy. In the proposed system, three reservoirs have been added to a conventional CLC system to allow storage of the oxygen carrier particles, while a cavity solar receiver has been chosen for the fuel reactor. The performance of the system is evaluated using ASPEN PLUS software, with the model being validated using independent simulation result reported previously. Operating temperature, solar efficiency, solar fraction, exergy efficiency and the fraction of the solar thermal energy stored for a based load power generation application are reported.; Mehdi Jafarian , Maziar Arjomandi, Graham J. Nathan

‣ Accelerated thermal cycling test of microencapsulated paraffin wax/polyaniline made by simple preparation method for solar thermal energy storage

Silakhori, M.; Naghavi, M.S.; Metselaar, H.S.C.; Mahlia, T.M.I.; Fauzi, H.; Mehrali, M.
Fonte: MDPI AG Publicador: MDPI AG
Tipo: Artigo de Revista Científica
Publicado em //2013 Português
Relevância na Pesquisa
77.29533%
Microencapsulated paraffin wax/polyaniline was prepared using a simple in situ polymerization technique, and its performance characteristics were investigated. Weight losses of samples were determined by Thermal Gravimetry Analysis (TGA). The microencapsulated samples with 23% and 49% paraffin showed less decomposition after 330 °C than with higher percentage of paraffin. These samples were then subjected to a thermal cycling test. Thermal properties of microencapsulated paraffin wax were evaluated by Differential Scanning Calorimeter (DSC). Structure stability and compatibility of core and coating materials were also tested by Fourier transform infrared spectrophotometer (FTIR), and the surface morphology of the samples are shown by Field Emission Scanning Electron Microscopy (FESEM). It has been found that the microencapsulated paraffin waxes show little change in the latent heat of fusion and melting temperature after one thousand thermal recycles. Besides, the chemical characteristics and structural profile remained constant after one thousand thermal cycling tests. Therefore, microencapsulated paraffin wax/polyaniline is a stable material that can be used for thermal energy storage systems.; Mahyar Silakhori, Mohammad Sajad Naghavi...

‣ Nonlinear dynamic per-unit models for electrochemical energy systems : application to a hardware-in-the-loop hybrid simulation

Gauchía Babé, Lucía
Fonte: Universidade Carlos III de Madrid Publicador: Universidade Carlos III de Madrid
Tipo: Tese de Doutorado Formato: application/pdf
Português
Relevância na Pesquisa
77.831626%
La situación energética actual está dominada por los combustibles fósiles, especialmente por el petróleo. Esta dependencia se está conviertiendo en arriesgada debido a las decrecientes reservas, a la incertidumbre de los recursos de petróleo y a las consecuencias económicas y políticas de una concentración de reservas en países de Oriente Medio. El sector transportes tiene una particular dependencia del petróleo como combustible y es una fuente de contaminación debido a su combustión. De cara a reducir esta dependencia se están introduciendo energías renovables como fuentes alternativas de energía. Las más comunes son la eólica y la fotovoltaica, aunque existen otros tipos, como las energías mareomotriz, de gradiente térmico, biomasa o undomotriz. El principal inconveniente de estas energías es su carácter no programable, que fomenta el uso de sistemas de almacenamiento de energía. Las energías renovables mencionadas no son aplicables a vehículos, por lo que para el sector transportes es más interesantes el uso de vectores energéticos tales como el hidrógeno. El hidrógeno puede ser un sustituto del petróleo para aplicaciones vehiculares, pero primero se han de resolver ciertos problemas, como son el elevado coste...

‣ A review of energy storage technologie sfor marine current energy systems

ZHOU, Zhibin; BENBOUZID, Mohamed; CHARPENTIER, Jean-Frederic; SCUILLER, Franck; TANG, Tianhao
Fonte: Pergamon Publicador: Pergamon
Português
Relevância na Pesquisa
77.825005%
Increasing concerns about the depletion of fossil resources and the issue of environment lead to a global need for producing more clean energy from renewable sources. Ocean is appreciated as a vast source of renewable energies. Considering marine renewable energies, it can be noticed that significant electrical power can be extracted from marine tidal currents. However, the power harnessed from marine tidal currents is highly fluctuant due to the swell effect and the periodicity of the tidal phenomenon. To improve the power quality and make the marine generation system more reliable, energy storage systems can play a crucial role. In this paper, an overview and the state of art of energy storage technologies are presented. Characteristics of various energy storage technologies are analyzed and compared for this particular application. The comparison shows that high-energy batteries like sodium–sulphur battery and flow battery are favorable for smoothing the long-period power fluctuation due to the tide phenomenon while supercapacitor and flywheel are more suitable for eliminating short-period power disturbances due to swell or turbulence phenomena. This means that hybrid storage technologies are needed for achieving optimal results in tidal marine current energy applications.; This work was funded by BMO (Brest Métropole Océane)

‣ Energy Storage Technologies for Smoothing Power Fluctuations in Marine Current Turbines

ZHOU, Zibhin; BENBOUZID, Mohamed; CHARPENTIER, Jean-Frederic; SCUILLER, Franck; TANG, Tianhao
Fonte: IEEE Publicador: IEEE
Português
Relevância na Pesquisa
77.79001%
With regard to marine renewable energies, significant electrical power can be extracted from marine tidal current. However, the power harnessed by a marine current turbine varies due to the periodicity of the tidal phenomenon and could be highly fluctuant caused by swell effect. To improve the power quality and make the marine current generation system more reliable, energy storage systems will play a crucial role. In this paper, the power fluctuation phenomenon is described and the state of art of energy storage technologies is presented. Characteristics of various energy storage technologies are analyzed and compared for marine application. The omparison shows that high-energy batteries like sodiumsulphur battery and flow battery are favorable for smoothing the long-period power fluctuation due to the tide phenomenon while supercapacitors and flywheels are suitable for eliminating short-period power disturbances due to swell or turbulence phenomena. It means that hybrid storage technologies are needed for achieving optimal performance in marine current energy systems.

‣ Impacts of energy storage on short term operation planning under centralized spot markets

Palma Behnke, Rodrigo Ernesto; Pereira Bonvallet, Eduardo; Zhang, Xiao Ping; Suazo Martínez, Carlos
Fonte: IEEE Publicador: IEEE
Tipo: Artículo de revista
Português
Relevância na Pesquisa
87.63959%
Artículo de publicación ISI; Abstract—Energy Storage Systems (ESS) are an alternative to provide flexibility in power system operation. ESS have been foreseen as crucial technologies to facilitate the transition to a low-carbon energymatrix that integrates higher level of renewable variable energy resources. In this paper, the integration of grid-scale ESS in short term operational planning under a centralized cost-based electricity market is analyzed through an adapted stochastic unit commitment formulation to provide energy arbitrage, primary or/and secondary reserve. Several computational simulations are performed in a realistic study case to discuss techno-economic effects of ESS integration in detail. Results obtained show that value of storage is increased when ESS jointly provide different services. Additionally, ESS enable greater participation of renewables into generation mix, while reducing impacts on flexible power plants. Influence of ESS in marginal price signals is also discussed. The undertaken discussion provides insight information for agents in liberalized markets.

‣ A comparison of PV/electrolyser and photoelectrolytic technologies for use in solar to hydrogen energy storage systems

Conibeer, Gavin; Richards, Brendon
Fonte: Pergamon-Elsevier Ltd Publicador: Pergamon-Elsevier Ltd
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
77.68173%
The approach of using hydrogen for an energy store to offset seasonal variations in solar energy is one very much at the periphery of current renewable energy system design. Nonetheless, its inherent advantages for long term storage in stand alone power s

‣ Generalized Model of VSC-based Energy Storage Systems for Transient Stability Analysis

Ortega, Álvaro; Milano, Federico
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 17/09/2015 Português
Relevância na Pesquisa
67.70246%
This paper presents a generalized energy storage system model for voltage and angle stability analysis. The proposed solution allows modeling most common energy storage technologies through a given set of linear differential algebraic equations (DAEs). In particular, the paper considers, but is not limited to, compressed air, superconducting magnetic, electrochemical capacitor and battery energy storage devices. While able to cope with a variety of different technologies, the proposed generalized model proves to be accurate for angle and voltage stability analysis, as it includes a balanced, fundamental-frequency model of the voltage source converter (VSC) and the dynamics of the dc link. Regulators with inclusion of hard limits are also taken into account. The transient behavior of the generalized model is compared with detailed fundamental-frequency balanced models as well as commonly-used simplified models of energy storage devices. A comprehensive case study based on the WSCC 9-bus test system is presented and discussed.

‣ Second-generation high-temperature superconducting coils and their applications for energy storage

Yuan, Weijia
Fonte: University of Cambridge; Department of Engineering Publicador: University of Cambridge; Department of Engineering
Tipo: Thesis; doctoral; PhD
Português
Relevância na Pesquisa
78.05991%
The full text of this thesis is not available due to ongoing discussions regarding publication; Since a superconductor has no resistance below a certain temperature and can therefore save a large amount of energy dissipated, it is a 'green' material by saving energy loss and hence reducing carbon emissions. Recently the massive manufacture of high-temperature superconducting (HTS) materials has enabled superconductivity to become a preferred candidate to help generation and transportation of cleaner energy. One of the most promising applications of superconductors is Superconducting Magnetic Energy Storage (SMES) systems, which are becoming the enabling engine for improving the capacity, efficiency, and reliability of the electric system. SMES systems store energy in the magnetic field created by the flow of direct current in a superconducting coil. SMES systems have many advantages compared to other energy storage systems: high cyclic efficiency, fast response time, deep discharge and recharge ability, and a good balance between power density and energy density. Based on these advantages, SMES systems will play an indispensable role in improving power qualities, integrating renewable energy sources and energizing transportation systems. This thesis describes an intensive study of superconducting pancake coils wound using second-generation(2G) HTS materials and their application in SMES systems. The specific contribution of this thesis includes an innovative design of the SMES system...

‣ The Potential of Energy Storage Systems with Respect to Generation Adequacy and Economic Viability

Bradbury, Kyle Joseph
Fonte: Universidade Duke Publicador: Universidade Duke
Tipo: Dissertação
Publicado em //2013 Português
Relevância na Pesquisa
88.15409%

Intermittent energy resources, including wind and solar power, continue to be rapidly added to the generation fleet domestically and abroad. The variable power of these resources introduces new levels of stochasticity into electric interconnections that must be continuously balanced in order to maintain system reliability. Energy storage systems (ESSs) offer one potential option to compensate for the intermittency of renewables. ESSs for long-term storage (1-hour or greater), aside from a few pumped hydroelectric installations, are not presently in widespread use in the U.S. The deployment of ESSs would be most likely driven by either the potential for a strong internal rate of return (IRR) on investment and through significant benefits to system reliability that independent system operators (ISOs) could incentivize.

To assess the potential of ESSs three objectives are addressed. (1) Evaluate the economic viability of energy storage for price arbitrage in real-time energy markets and determine system cost improvements for ESSs to become attractive investments. (2) Estimate the reliability impact of energy storage systems on the large-scale integration of intermittent generation. (3) Analyze the economic, environmental, and reliability tradeoffs associated with using energy storage in conjunction with stochastic generation.

First...

‣ Design and Assembly of Hybrid Nanomaterial Systems for Energy Storage and Conversion

Cheng, Yingwen
Fonte: Universidade Duke Publicador: Universidade Duke
Tipo: Dissertação
Publicado em //2013 Português
Relevância na Pesquisa
77.784536%

Energy storage systems are critically important for many areas in modern society including consumer electronics, transportation and renewable energy production. This dissertation summarizes our efforts on improving the performance metrics of energy storage and conversion devices through rational design and fabrication of hybrid nanomaterial systems.

This dissertation is divided into five sections. The first section (chapter 2) describes comparison of graphene and carbon nanotubes (CNTs) on improving the specific capacitance of MnO2. We show that CNTs provided better performance when used as ultrathin electrodes but they both show similar performance with rapid MnO2 specific capacitance decrease as electrodes become thicker. We further designed ternary composite electrodes consisting of CNTs, graphene and MnO2 to improve thick electrode performance (chapter 3). We demonstrate that these electrodes were flexible and mechanically strong, had high electrical conductivity and delivered much higher capacity than electrodes made without CNTs.

Chapter 4 describes assembly of flexible asymmetric supercapacitors using a graphene/MnO2/CNTs flexible film as the positive electrode and an activated carbon/CNTs flexible film as the negative electrode. The devices were assembled using roll-up approach and can operate safely with 2 V in aqueous electrolytes. The major advantage of these devices is that they can deliver much higher energy under high power conditions compared with those designed by previous studies...

‣ Single-walled carbon nanotube film for electrochemical energy storage devices

Rong, Jiepeng
Fonte: University of Delaware Publicador: University of Delaware
Tipo: Tese de Doutorado
Português
Relevância na Pesquisa
77.6808%
Wei, Bingqing; Development of materials and structures leading to high energy and power density electrochemical energy storage systems is a major requirement to the power needs of portable electronics and electric vehicles. Lithium-ion batteries and electrical double-layer capacitors are among the leading electrical energy storage technologies today. Carbon nanotubes (CNTs), since the discovery in 1991, have exhibited promising applications in electrochemical energy storage by taking advantage of their unique mechanical, chemical, and electrical properties. Two concrete examples of CNT macro-film ‘s applications in lithium-ion batteries and electrical double-layer capacitors are demonstrated in this thesis. Lithium-ion batteries with substantially higher specific capacity and better cycling performance are needed in next generation portable electronics, especially if all-electric vehicles are to be deployed broadly as replacements for gasoline-powered vehicles. Silicon (Si) is an attractive anode material being closely scrutinized for use in lithium-ion batteries but suffers from a poor cyclability and early capacity fading. A simple method to fabricate tandem structure of porous Si film on CNT film to significantly improve cycling stability of Si film as lithium-ion battery anode materials was reported in this thesis. With the new structure...

‣ Smart battery management systems: towards an efficient integration of electrical energy storage in smart regions

Gano, A. J.; Silva, Hugo M.; Correia, João Bernardino; Martins, Maria João
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em //2013 Português
Relevância na Pesquisa
77.987314%
Electrical energy storage systems for electric vehicles or stationary applications will be important actors in Smart Region's energy scenarios, strongly contributing to increase the efficient and sustainable use of available resources. However, massive integration of such systems stillposes many problems, requiring enhancements in batteries's life time, autonomy, reliability and cost. The development of new smart and accurate battery management systems able to communicate with a broad range of smart devices and energy management systems, to account with users' needs and smart management directives, are essential to operate such battery based energy storage systems, improving their overall performance. The paper discusses some of the technological developments needed in this domain and the requirements of smart battery management systems to comply with, presenting a modular hardward platform, developed at LNEG, as an example of required structure and functionalities, relevant both in electrical mobility and decentralized smart-grid energy storage systems.

‣ Regulation of the wind power production: contribution of the electric vehicles and other energy storage systems

Mateus, C. B.; Estanqueiro, Ana
Fonte: Laboratório Nacional de Energia e Geologia Publicador: Laboratório Nacional de Energia e Geologia
Tipo: Conferência ou Objeto de Conferência
Publicado em //2012 Português
Relevância na Pesquisa
87.63959%
The increase in penetration of variable renewable energy sources (RES) introduced additional difficulties regarding the management of the Portuguese Power System. This is mainly due to the high temporal variability and low controllability, characteristics of these kinds of sources. There is a real need to reduce the impact of non-dispatchable RES sources; maximizing their penetration and minimizing curtailment. This is especially true for the wind power and run-of-the-river hudro (ROR); as it appears beneficial to combine their variable production with added capacity of energy storage and demand side management; thereby increasing the flexibility of the power system as a whole. This paper aims to assess the excess wind generation (and other non-dispatchable sources); this for periods of production's excess in a 2020 timeframe, and assuming different weather scenarios. The adjustment of wind power generation (WPG) profile to the load prfile is also addressed; the result is computed in the form of the value of the energy temporally deferred, using Pumped Hydro Storage (PHS) power plants as well as electric Vehicles (EVs)

‣ Energy storage for wind integration: hydropower and other contributions

Estanqueiro, Ana; Ardal, Atle Rygg; O'Dwyer, Ciara; Flynn, Damian; Huertas-Hernando, Daniel; Lew, Debra; Gomez-Lázaro, E.; Ela, Erik; Revuelta, Javier; Kiviluoma, J.; Rodrigues, L.; Amelin, Mikael; Holttinen, Hannele
Fonte: IEEE - Institute of Electrical and Electronics Engineers Publicador: IEEE - Institute of Electrical and Electronics Engineers
Tipo: Conferência ou Objeto de Conferência
Publicado em //2012 Português
Relevância na Pesquisa
67.602705%
The amount of wind power and other timevariable non-dispatchable renewable energy sources (RES) is rapidly increasing in the world. A few power systems are already facing very high penetrations from variable renewables which can surpass the systems’ consumption during no-load periods, requiring the energy excess to be curtailed, exported or stored. The limitations of electric energy storage naturally lead to the selection of the well-known form of storing potential energy in reservoirs of reversible hydropower stations, although other technologies such as heat storage are also being used successfully. This paper reviews the storage technologies that are available and may be used on a power system scale and compares their advantages and disadvantages for the integration of fast-growing renewables, such as wind power, with a special focus on the role of pumped hydro storage.

‣ Experimental analysis of a solar absorption system with interior energy storage

Pastakkaya,Bilsay; Yamankaradeniz,Nurettin; Kaynakli,Omer; Coskun,Salih; Yamanakaradeniz,Recep
Fonte: Journal of Energy in Southern Africa Publicador: Journal of Energy in Southern Africa
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2012 Português
Relevância na Pesquisa
67.79595%
This study examines experimentally the cooling application of a solar absorption system with interior energy storage that uses two different auxiliary systems. The experiments were performed at Uludag University, Bursa, Turkey on the 3rd and 4th of August 2010 that had the approximately same average outdoor temperature, 31°C. A solar hot water was delivered via a 40 m2 array of flat plate solar collectors that drove a lithium chloride (LiCl) absorption heat pump with a cooling power peak of 20 kW. A solar-powered air conditioning system was designed for heating and cooling in a test room that had a total floor space of 30 m2. Chilled water produced in the evaporator was supplied to the fan coil units, and the heat of condensation and absorption was rejected by means of a wet cooling tower. An electric heater and an air source heat pump were used as auxiliary systems for the absorption cooling application for two different cases when the solar energy was insufficient. Temperature variations were recorded for the absorption machine components, the test room, and the outdoors. The cooling energy, thermal energy, and daily average coefficient of performance (COP) of the absorption system were calculated for two days. Solar absorption cooling was considered for two different auxiliary systems and is presented in this manuscript. The results showed that the daily average COP of the absorption system was 0.283 for Case 1 and 0.282 for Case 2. For both cases...

‣ The potential impact of small-scale flywheel energy storage technology on Uganda's energy sector

Okou,Richard; Sebitosi,Adoniya Ben; Khan,Azeem; Pillay,Pragasen
Fonte: Journal of Energy in Southern Africa Publicador: Journal of Energy in Southern Africa
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2009 Português
Relevância na Pesquisa
87.91336%
The energy crisis in Uganda has caused a sharp decline in the growth of the industry sector from 10.8% to 4.5% between 2004/5 and 2005/6. This crisis has escalated the power disruptions, which have had adverse effects on various sectors. While business owners have resorted to importation of fossil fuel generators that have increased the cost of production, others have resorted to battery energy storage systems to cater for short outages, which are limited in life span, depth of discharge, among others. These interventions have, thus, further increased the cost of goods and services. In addition, the rural populations using solar home systems incur high battery maintenance and replacement costs. In this paper an electromechanical flywheel battery is proposed as a better alternative in mitigating energy storage problems. It is found that by replacing the battery storage systems with the electromechanical flywheel battery, a saving of up to 35% on cost of energy can be made in the solar home systems and for the industry sector, the power disruptions could be reduced.