ENERBASE - Catálogo bibliográfico de Energia. Pesquisa: "DE Solar energy" + "DE Solar energy$" Resultados de 1 a 5 sobre 154 encontrados.
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Autor: BARREIROS, Maria Alexandra
Título: Microscopy techniques for dye distribution in DSCs nanocrystalline TiO2 films / Maria Alexandra Barreiros, Sara Sequeira, Luís C. Alaves, V. Corregidor, Fernanda Guimarães, João Mascarenhas, Maria João Brites
In: Microscopy and Microanalysis. - Vol. 21, Supplement S6 (2015), p. 88-89
Resumo de autor: ABSTRACT: Capture of sunlight has attracted an increasing interest in the scientific community and triggered the development of efficient and cheap photovoltaic devices. Amongst recent generation technologies for solar energy conversion, dye-sensitized solar cells (DSCs) show an optimal trade-off between high-conversion efficiency and low-cost manufacturing. For the last two decades, significant progress has been made and best energy conversion efficiency of the DSC at the laboratory scale has surpassed 12% [1]. A lot of work has focused on the enlargement of surface areas to enhance the amount of adsorbed dyes by reduction of nanoparticle sizes or utilization of novel structures. Nevertheless there remain some crucial details of DSC operation for which limited information is available, namely dye diffusion and adsorption, surface coverage and dye distribution throughout the nc-TiO2 film. Microprobe techniques can be powerful tools to evaluate the dye load, the dye distribution and dye depth profile in sensitized films. Electron Probe Microanalysis (EPMA) and Ion Beam Analytical (IBA) techniques using a micro-ion beam, namely micro-Particle Induced X-ray Emission ( PIXE) and Rutherford Backscattering Spectrometry (RBS), were used to quantify and to study the distribution of the ruthenium organometallic (N719) dye in TiO2 films, profiting from the different penetration depth and beam sizes of each technique. Two different types of films were prepared and sensitized, mesoporous nanoparticles and 1D nanostructured TiO2 films (figure 1). Despite the low concentration of Ru, the high sensitive analytical techniques used allowed to assess the Ru surface distribution and depth profile. Fig. 2 shows the PIXE maps of Ru and Ti indicating an homogeneous surface distribution. The same figure presents the RBS spectra obtained with a 2 MeV proton beam of the same sample showing that a good spectra fit is obtained considering only two sample layers: the first one with a 1.7 ìm thickness; the second one being the SiO2 substrate. The Ru RBS signal also shows that the dye has an homogeneous depth distribution. Due to the fine spatial resolution of the EPMA/WDS (Wavelength Dispersive Spectroscopy) technique it was possible to visualise the dye distribution in sample cross-section (with micrometer or submicrometer dimensions) as presented in Fig. 3 for the elemental mapping of a mesoporous nanoparticle TiO2 film. Dye load evaluation by two different techniques (ìPIXE and EPMA/WDS) provided similar results (Ru/Ti values around 0.5 %). The distribution analysis of the organometallic dye (N719) was done through ruthenium distribution via X-ray mapping. RBS was used to assess the ruthenium depth profile. This assessment can lead to a better understanding of the device performance.
Subject: Titanium dioxide / Nanostructured materials / Solar energy conversion / Solar cells / Dyes
URL: http://doi.org/10.1017/S1431927614014147
URL: http://hdl.handle.net/10400.9/2891
Cota: LEN-NBAH: UESPAPERS BAR
Tipo de documento: Texto impresso

Outro(s) autor(es) : Sequeira, S. / Alves, L. C. / Corregidor, V. / Guimarães, Fernanda M. G. / Mascarenhas, João / Brites, Maria João



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Autor: CARDOSO, João P.
Título: Harnessing the sun: concentrated solar power [Comunicação oral] / João Cardoso
In: Seminário: Mestrado Engenharia e Gestão de Energia, IST-Instituto Superior Técnico, Lisboa, Portugal, 16 Dezembro, 2014.
Subject: Solar energy / Concentrating solar power
URL: http://hdl.handle.net/10400.9/2795
Cota: LEN-NBAH: UESPAPERS CAR
Tipo de documento: Texto impresso



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Autor: LEW, Debra
Título: Wind and solar curtailment / Debra Lew, Lori Bird, Michael Milligan, Bethany Speer, Xi Wang, Enrico M. Carlini, Ana Estanqueiro, Damian Flynn, E. Gomez-Lázaro, Hannele Holttinen, Nickie Menemenlis, Antje Orths, J. Charles Smith, Lennart Söder, Poul Sorensen, Argyrios Altiparmakis, Yasuda Yoh
In: 12th International Workshop on Large-Scale Integration of Wind Power into Power Systems as well as on Transmission Networks for Offshore Wind Power Plants, Book of Proceedings, London, UK, 22-24 October, 2013, 7 p.
Resumo de autor: ABSTRACT: High penetrations of wind and solar generation on power systems are resulting in increasing curtailment. Wind and solar integration studies predict increased curtailment as penetration levels grow. This paper examines experiences with curtailment on bulk power systems internationally. It discusses how much curtailment is occurring, how it is occurring, why it is occurring, and what is being done to reduce curtailment. This summary is produced as part of the International Energy Agency Wind Task 25 on Design and Operation of Power Systems with Large Amounts of Wind Power.
Subject: Wind energy / Solar energy / Curtailment / Transmission congestion
URL: http://hdl.handle.net/10400.9/2463
Cota: LEN-NBAH: UAERPAPERS EST
Tipo de documento: Texto impresso

Outro(s) autor(es) : Bird, Lori / Milligan, Michael / Speer, Bethany / Wang, Xi / Carlini, Enrico M. / Estanqueiro, Ana / Flynn, Damian / Gomez-Lázaro, E. / Holttinen, Hannele / Menemenlis, Nickie / Orths, Antje / Smith, J. Charles / Söder, Lennart / Sorensen, Poul / Altiparmakis, Argyrios / Yoh, Yasuda



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Autor: YASUDA, Yoh
Título: Flexibility chart: Evaluation on diversity of flexibility in various areas / Yoh Yasuda, Atle Rygg Ardal, Enrico M. Carlini, Ana Estanqueiro, Damian Flynn, E. Gomez-Lázaro, Hannele Holttinen, J. Kiviluoma, Bernhard Lange, Nickie Menemenlis, Michael Milligan, Antje Orths, Charles Smith, Lennart Söder
In: 12th International Workshop on Large-Scale Integration of Wind Power into Power Systems as well as on Transmission Networks for Offshore Wind Power Plants, Book of Proceedings, London, UK, 22-24 October, 2013, 6 p.
Resumo de autor: ABSTRACT: This paper evaluates various aspects of flexibility in power systems worldwide within the multi-country study framework of IEA Wind Task 25, including grid components and actions which have been favoured for enhancing flexibility in different areas/countries/regions, and how TSOs/ISOs/ utilities intend to manage variable generation in their operating strategies. One methodology to evaluate the diversity of flexibility sources is a "flexibility chart”, which can illustrate several flexibility parameters (e.g. hydro, CCGT, CHP, interconnection) in a polygonal radar (spider) chart.
Subject: Wind energy / Variable generation / Solar energy / System flexibility / Interconnection
URL: http://hdl.handle.net/10400.9/2460
Cota: LEN-NBAH: UAERPAPERS EST
Tipo de documento: Texto impresso

Outro(s) autor(es) : Ardal, Atle Rygg / Carlini, Enrico M. / Estanqueiro, Ana / Flynn, Damian / Gomez-Lázaro, E. / Holttinen, Hannele / Kiviluoma, J. / Van Hulle, Frans / Kondoh, Junji / Lange, Bernhard / Menemenlis, Nickie / Milligan, Michael / Orths, Antje / Smith, J. Charles / Söder, Lennart



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Autor: DURÃO, Bruno
Título: Optimization of a seasonal storage solar system using Genetic Algorithms / Bruno Durão, António Joyce, J. Farinha Mendes
In: Solar Energy. - Vol. 101 (2014), p. 160-166
Resumo de autor: ABSTRACT: Seasonal storage solar systems are capable of storing thermal energy, from one season to another (typically a few months). In the present paper solar thermal energy generated during summer time, is stored for use in winter time (typically 120 days). The analyzed system consists of solar thermal collectors and a sensible heat storage device using water as storing media. The area of solar collector and the capacity of the storage tank are the basic sizing parameters, which have to meet the requirements of the load. The present case study considers the utilization of the seasonal storage solar system for heating greenhouses, with a 50 kW heating load. The whole system was modeled using a dynamic modeling tool and the sizing parameters were optimized through a Genetic Algorithm process. This optimization process was compared with other optimization methods by a pattern search, and the results showed the benefits of the Genetic Algorithm process.
Subject: Solar Energy / Thermal Storage / Seasonal Storage / Genetic Algorithms
URL: http://dx.doi.org/10.1016/j.solener.2013.12.031
URL: http://hdl.handle.net/10400.9/2170
Cota: LEN-NBAH: UESPAPERS JOY
Tipo de documento: Texto impresso

Outro(s) autor(es) : Joyce, António / Mendes, J. Farinha



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