1,720,981 research outputs found
Characterization of the Ecosole HCPV tracker and single module inverter
No full textBECAR, the Beghelli group's RampD company, is leading ECOSOLE (Elevated COncentration SOlar Energy), one of the largest European Demonstration projects in solar photovoltaic. ECOSOLE, started in 2012, is focused on the study, design, and realization of new HCPV generator made of high efficiency PV modules equipped with SoG (Silicone on Glass) fresnel lenses and III-V solar cells, and a low cost matched solar tracker with distributed inverters approach. The project also regards the study and demonstration of new high throughput methods for the industrial large scale productions, at very low manufacturing costs. This work reports the description of the characterization of the tracker and single module. © 2015 AIP Publishing LLC
Mirrors array for a solar furnace: Optical analysis and simulation results
No full textThe optical design of a concentration system for a solar furnace is studied, proposing several possible solutions. The foreseen use of this solar furnace is to test components and methodologies for solar applications. The analysis assesses and compares the optical performances of several possible configurations. The possibility of employing in a solar furnace an array of off-axis mirrors as primary optics is examined comparing simulations with various diameters and different configurations. In particular the paper compares spherical mirrors, parabolic mirrors with axis inclined with respect to the heliostat rays and a paraboloid with axis parallel to the rays arriving from the heliostat. It proposes an optimal solution, with spherical mirrors on a spherical envelope, which is compared to the heliostat-axis paraboloid. Considering realisation tolerances, mirrors positioning, mirrors pointing and solar divergence effects they equivalently concentrate the sunlight on the receiver. © 2013 Elsevier Ltd
Rating of CPV modules: Results of module round robins
No full textThe results of three CPV module round robins are presented. Ten test labs around the world participated to the round robins in total. Each round robin used a different CPV module technology (Daido Steel, Soitec, Suncore). The data gathered at the test labs was used to test CSOC power rating procedures as basis for the IEC draft standard 62670-3. The deviation between the minimum and the maximum power output rated at the test labs was in average 4.4 % with a standard deviation of 1.8 %abs. This underlines that power ratings or CPV modules are reliable and reproducible. © 2016, American Institute of Physics Inc. All rights reserved
Forecasting the working temperature of a concentrator photovoltaic module by using artificial neural network-based model
No full textNowadays, the estimation of the PhotoVoltaic (PV) power production systems is crucial for ensuring their economic feasibility as well as their proper sizing in order to avoid outages and guarantee quality and continuity of supply. The working temperature of a PV module or system is a key parameter for the assessment of the actual performance of photovoltaic modules. PV modules are usually rated at Standard Test Conditions (STC = 1000W/m2, AM1.5, 25°C), but their operating temperatures are typically considerably higher. Power production can be highly influenced by cell working (module) temperature whose increase respect to standard one could gradually deteriorate system's energy performance. Correlations to evaluate performances referring to STC and/or applying some theoretical simplifications/assumptions are available in literature. However, it be noticed that the use of these correlations, under the same operative conditions, does not produce univocal results. In this paper, an Artificial Neural Network (ANN)-based model to forecast the working temperature of a Concentrator PhotoVoltaic (CPV) module (back - plate temperature) is proposed. A dataset consisting of meteorological data (i.e. solar direct normal irradiance, ambient temperature, wind speed and wind direction), measured every 1-minute and recorded from November 2012 to April 2014, concerning a 50 kWp CPV plant installed in the southwestern Europe, is used for the training and testing of the ANN developed. The main advantage of the proposed approach is that it acts as black box tool, making easy to model an arbitrary complex non-linear relationship between inputs and outputs. In fact, in this case no in-depth knowledge of the system and its components is required contrary to what needed by deterministic techniques. In order to verify the effectiveness and the accuracy of the approach here proposed, measured and estimated data were analysed and compared considering different error metrics. © 2016, American Institute of Physics Inc. All rights reserved
Low-cost solar simulator for CPV cells characterizations
No full textThe fast development of the CPV technology requires the use of photovoltaic cells more and more small and with very high conversion efficiency: optics and modules are designed to reach nominal concentration ratio up to 1000X [1]. In this technological framework, it is very important to test the cell performances using a laboratory equipment, as a solar simulator, able to generate on the cell an irradiance corresponding to the real working conditions. In the market, it is possible to buy several systems designed and produced by specialized Companies or Research Institutes able to make a reliable cell characterization. Unfortunately, these systems are very expensive, because they are built with components specially developed for this purpose. In this paper the authors present a solar simulator for concentrating photovoltaic cells realized with cheap standard components normally used for other scopes. The results is a prototypal system having a cost significantly lower than the commercial solar simulators. Main disadvantage of this approach is that a good power density uniformity on the measurement point is reached only for small size cells (diameter less than 4mm). © 2018 Author(s)
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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