1,721,005 research outputs found
Optimal design and management for hydrogen and renewables based hybrid storage micro-grids
No full textIn an energy sustainability perspective, the renewables penetration is expected to importantly increase over the next decade, requiring modifications in the current electric system in terms of flexibility and reliability. In this respect, storage systems will play a central role and the production of green hydrogen is seen as a promising solution for both short-term and seasonal storage.
In this context, the aim of this paper is the development of a methodology for the
optimal design of hybrid storage micro-grids based on renewables and hydrogen and the definition of an optimal management strategy in a perspective of hydrogen employment as seasonal storage. In detail, an optimization code e based on mathematical models for each component and on specifically developed optimization strategies for the management of the components interaction e will be presented and applied to a case study. The code optimizes the sizes of the integrated electrolyzer and fuel cell, based on an objective function that maximizes the storage efficiency. It has been applied to the S.A.P.I.E.N.T.E. micro-grid installed at the ENEA Research Centre near Rome (Italy) e composed of photovoltaic panels, batteries, heat pump and thermal storage systems e obtaining the optimal design of the hydrogen section to be integrated as seasonal storage strategy.
Furthermore, a parametric analysis on the battery size has been performed. The application of the developed optimization routine resulted in the introduction of a 3.7 kW electrolyzer and 4 kW fuel cell coupled with 36 kWh of battery capacity, enabling a total hydrogen production of about 87.5 kg (corresponding to 1159 kWh of electricity produced during the thermal year)
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
A novel solar concentrator system for combined heat and power application in residential sector
Full text linkThe research on photovoltaic conversion is continuously overtaking technological challenges and modern PV cells can nowadays be efficiently combined with solar concentrators. In this paper a new photovoltaic solar concentrator model based on non-imaging optics and embedding high efficiency multi-junctions cells is presented. The concentrator has been optimized to maximize the electricity production but it is thought to work in cogeneration to allow also for thermal energy by recovering the residual heat, since an active cooling system for the cells is necessary. The efficiency enhancement is obtained thanks to the high matching between the collected solar irradiance and the receiver electrical features. The aim of the paper is the definition of the number of residential utilities connected to the system in order to minimize the exchange of energy with the network and also the use of auxiliary boiler. Also the optimal size of electric and thermal storage to be integrated to the concentrator, has been determined as function of the number of utilities. To achieve these goals a parametric analysis has been carried out by the use of an in-house-developed calculation code considering a whole year of operation in order to estimate the energy fluxes and the economic performance. Furthermore, the maximum capital cost of the system has been estimated in order to achieve a return on the investment in ten or twenty years. According to the Authorsâ knowledge, the novelty of this study regards the implementation of this kind of photovoltaic solar concentrator â for combined heat and power production â in a residential application
Exploring the academic landscape of energy communities in Europe: A systematic literature review
Full text linkOver the past few years, energy communities initiatives have gained traction in Europe as a means to achieve energy transition goals, allowing citizen involvement in energy production, consumption, and distribution. Following the 2018 European directive RED II, these projects have rapidly increased across the continent, showcasing their potential for creating sustainable local energy systems. While studies highlight economic, environmental, and social benefits, barriers such as regulatory challenges, finance access, and low public awareness remain. This paper presents the results of a systematic literature review that explores the state-of-the-art of the academic research on energy communities. The study adopts a systematic approach to examine the body of literature on the topic to provide a comprehensive analysis of the phenomenon on the basis of rigorous and replicable research criteria. The reviewed material consists of 140 articles collected through the Scopus database, evaluated using specific structural dimensions to group the literature into analytical categories. The analysis of scientific papers published between 2018-2022 shows a growing attention towards Renewable Energy Communities, particularly those based on solar energy for electricity production, often combined with storage systems and heat pumps, whereas attention towards energy communities based on thermal energy production is still limited. Furthermore, most scholars focused on analysing specific territorial contexts; comparisons between different regions allows to highlight common features and elements characterizing each model. It emerged that the development of energy communities depends mainly on regulatory, financial, and managerial barriers that require an adequate institutional and legal framework capable of promoting their diffusion. Most studies address the topic from an economic perspective, often in association with incentivizing community models. However, a social perspective should be included by introducing the concept of energy sharing and methodologies for its distribution among all members of the community. The scientific community is called upon to continue investigating and supporting the development of community energy initiatives by providing evidence-based recommendations to policymakers, industry stakeholders, and local communities. This can help to overcome existing barriers and facilitate the diffusion of energy communities models, contributing to the achievement of sustainable and inclusive energy transition goals
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