1,720,963 research outputs found
An Optimized Heat Sink for Thermophotovoltaic Panels
No full textIn the present work, an innovative hybrid solar panel is proposed, which can be used to pave floors or to cover roofs. A particular heat sink is employed, which gives robustness to the panel and provides a better heat transfer effectiveness with respect to tube heat exchangers. The geometry of the heat sink which is employed in the panel is optimized with the help of a numerical model and a genetic algorithm. Some optimization examples are shown. The velocity and temperature distributions on the heat sink cross section are also investigated. The presented hybrid panel allows till 20% increase in the electrical efficiency with respect to a simple photovoltaic panel. Moreover, it can be easily installed under every environmental condition due to its robustness and resistance to water infiltration
Analysis of different Hybrid TEG/TEC Configurations
Full text linkThe growing demand for electricity and the looming environmental crisis are the main challenges to be faced and solved today. This calls for innovative energy conversion systems, for which efficiency and reliability are among the most
sought-after features. Thermoelectric generators are devices that can offer partial or complete solutions to these challenges of the new millennium. The advantages of these technologically advanced devices are many: they are environmentally friendly, reliable and have a long service life. Furthermore, by applying thermoelectric generators, it is possible to improve the efficiency of existing systems or meet the electricity demand of different systems with high flexibility. At the same time, their low conversion efficiency has so far prevented their wide application, limiting them
mainly to research. However, recent advances in thermoelectric materials and devices are pushing this technology to find its place among state-of-the-art energy conversion systems. This review explores the state of the art in terms of research
and solutions already on the market, in order to illustrate a comprehensive and realistic perspective of the PV-TEG/TEC structures
APPARATO DI SUPPORTO E RAFFREDDAMENTO DI UN PANNELLO FOTOVOLTAICO
No full textL'apparato è ideato per alloggiare più celle fotovoltaiche provvedendo ad aumentarne l’efficienza di conversione dell’energia solare in energia elettrica abbassandone la temperatura e sfruttando l’effetto Seebeck-Peltier per incrementando l’energia elettrica resa disponibile. L’oggetto è costituito da una lastra di alluminio su cui vengono incollate le celle fotovoltaiche utilizzando una pasta termoconduttiva ed elettroisolante. La lastra è rivestita sulla superficie inferiore con uno strato di materiale elastico isolante elettrico con elevata conduttività termica ed è fissata a due pareti di alluminio a loro volta fissate sul lato opposto ad una seconda lastra rivestita sulla superficie superiore con lo stesso materiale elastico termoconduttivo ed elettroisolante. Tra le due lastre è posta una serie di file di profilati di due diversi materiali conduttori o semiconduttori elettrici uniti insieme mediante incastri a pressione. Tra le due lastre e le due pareti laterali viene fatto scorrere un fluido liquido o gassoso che asporta calore dai profilati per convezione forzata o naturale. Il modulo può essere completato con due pareti trasversali con raccordi di ingresso e uscita del fluido o può venire unito ad altri moduli
Integrated apparatus for supporting and cooling a photovoltaic panel
Full text linkThe patented integrated Thermoelectric Generator (TEG) cooling system efficiently and space-savingly removes heat from solar cells during periods of high solar radiation. Unlike existing products that utilise the Peltier and Seebeck effect, in the patented system the Seebeck effect occurs internally in the heat sink itself, which acts entirely as a carrier for the cells, and only a small part of the removed heat is used to provide the required temperature difference. The invention results in a clear simplification of solar cell cooling and thermoelectric conversion technology. This also leads to cascading economic advantages in terms of overall system costs. We have started extensive research into new innovative and efficient materials to further improve the efficiency of the system and provide an increasingly competitive product for the market..We are looking for collaborators, joint-venturers and investors
Experimental Investigation on the Pressure Drop of Air Flows Through Aluminum and Nickel-Chromium Metallic Foams for HVAC Applications
Full text linkIn this paper, a series of experimental data about the role of the metal foam thickness on the total air flow pressure drop is presented. The tested metallic foams are based on aluminum and nickel-chromium and they are characterized by a considerable value of porosity (>0.92) and by a number of pores per linear inches (PPI) close to 10. The measures were conducted in a range of air velocity values typical for HVAC fan-coils. Under these conditions, the flow regime into the pores is highly turbulent. It was demonstrated that below a threshold value of the ratio between the thickness of the porous medium (H) and the characteristic dimension of the pores (d), the dispersion of the pressure drop values from a sample to another one can be very high. This behavior can limit the industrial use of these materials. In addition, the results presented in this paper confirm that the pressure drop data obtained under highly turbulent conditions can be conveniently used in order to determine the inertia coecient, C, of the metal foam
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
- …
