3,137 research outputs found
Experimental modeling of the optical and energy performances of a point-focus CPV system applied to a residential user
No full textThere is not a standard configuration of Concentrating Photovoltaic (CPV) systems on the market because it must be defined according the user characteristics. Hence, it is important to evaluate the real optical and energy performances of CPV system to satisfy accurately the user energy demands. An experimental model able to calculate energy and optical performances of CPV system with Triple-Junction (TJ) cells, is presented in this paper. First, optical performances influencing the CPV system electrical producibility, are evaluated. Optical concentration factor (Copt) and optical efficiency are experimentally determined in terms of distance between TJ cell and optics. Successively, a black-box model able to link simultaneously TJ cell electrical power with Direct Normal Irradiation (DNI) and TJ cell temperature when Copt varies, is adopted; it is difficult to link these variables by means of a white-box model. This link is basic to evaluate the real CPV system performances when it is sized to match the user energy loads. Hence, the CPV system feasibility applied to 120 m2 residential user, is evaluated. The modules optimal number is defined to maximize the investment profitability. The modules optimal number is five with a Net Present Value equal to 7.2 k€
Energy and economic analysis of a point-focus concentrating photovoltaic system when its installation site varies
No full textThe concentrating photovoltaic (CPV) systems are a promising technology to obtain clean energy. However, these systems are not equally convenient worldwide due to different climatic conditions. The main aim of this paper is to analyze energy and economic performances of a point-focus CPV system for a residential user when its installation site varies. Three locations, Riyadh, Copenhagen, and Palermo, characterized by very different weather conditions are chosen. A model that links the electrical power of a triple-junction (TJ) cell with its temperature and concentrated radiation incident on it is experimentally developed to evaluate the energy performance of the CPV system. A comparison of the three localities for typical winter and summer sunny days indicates that the higher values of the TJ cell temperature are reached in summer, over 70°C at Riyadh, and its electrical power is reduced compared to a winter day. In winter, a TJ cell in Riyadh supplies an electric power of about 20% higher than that in other two cities, while in summer, the maximum power is observed at Copenhagen. On the contrary, the electrical producibility also depends on the sunlight daily hours number during the year. Hence, considering the real distribution of direct normal irradiance (DNI) and the environmental temperature for each locality, a CPV system composed of modules of 90 cells adopted for a residential user is sized. The electric producibility of the CPV system, by varying its module number, is evaluated for different localities together with the optimal number of the modules which is able to maximize the investment profitability
A imagem de Alessandro Baricco no Brasil
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Comunicação e Expressão, Programa de Pós-Graduação em Estudos da Tradução, Florianópolis, 2013.Com a intenção de delinear o modo pelo qual o escritor italiano Alessandro Baricco se inseriu no sistema literário brasileiro e os caminhos percorridos pelos seus livros traduzidos, esta dissertação dá voz às experiências tradutórias de seus tradutores. A inserção de Bariccono Brasil tem seu início em 1997, através de uma proposição da Profa. Dra. Roberta Barni à editora Iluminuras da tradução de Oceano Mare. A partir daí, outras sete obras foram publicadas no Brasil, sendo três delas traduzidas por Roberta Barni e as outras quatro por quatro tradutores diferentes. De um lado, considera-se o tradutor como figura principal namediação entre culturas, e, de outro, se analisa a realidade desta figuradentro do sistema literário, sua invisibilidade, seus limites e o exercíciode sua profissão. A pesquisa conta, ainda, com críticas e resenhas referentes ao autor italiano publicadas em jornais consagrados no Brasil, considerando estas como parte constituinte da imagem de Baricco refletida em território nacional. Abstract : Intending to delineate the way the Italian writer Alessandro Baricco has been inserted in the Brazilian literary system and the paths his translated books have followed, this thesis gives voice to the translating experiences of his translators. Baricco's insertion in Brazil began in 1997, through a personal project of Dr. Roberta Barni, with her translation of Oceano Mare. Since then, seven other of his works have been published in Brazil, three of which were translated by Roberta Barni and the other four by four different translators. On the one hand,the translator is considered as the main figure in mediation betweencultures and, on the other, this figure's reality is analyzed within theliterary system: its invisibility, its limits and its professional practice. Criticisms and reviews of this Italian author published in well established Brazilian newspapers are also considered, with the understanding that they are part of Baricco's image reflected here
Feasibility analysis of a CPV system sized by means of a TJ cell black-box model and applied to a livestock farm
No full textIn the Concentrating Photovoltaic (CPV) systems, the Triple-Junction (TJ) cell electrical power is separately evaluated as function of its temperature or of the solar concentration factor (C), but generally not simultaneously as a function of both variables. Because all these variables are difficult to link by means of a white-box model, a mathematical model of the black-box type based on experimental data, is defined in this paper in order to link directly the TJ cell electric power together with Direct Normal Irradiance (DNI) and TJ cell temperature at different values of C. The knowledge of a link among TJ cell electric power, DNI and TJ cell temperature is basic to evaluate the real performances of a CPV system when it has to be sized, adopting a modular configuration, to meet the energy demands of a user. Hence, the feasibility of a CPV system adopted for an agricultural livestock farm located in Salerno (Italy), is evaluated by means of the model. The main activity of the farm is the breeding of cattle and sheep for milk production; the farm is made up of a stable and a farmhouse. The optimal number of TJ cells is defined to maximize the profitability of the investment, expressed in terms of Net Present Value. A CPV plant made up of 3000 cells, with an electric peak power of 6.6 kW, allows to maximize the NPV value up to about 16 k€
ANN model of a triple‐junction cell in concentrating photovoltaic system
No full textSignifcant advancements in concentrating photovoltaic (CPV) systems have been achieved in recent years, also thanks to the
defnition of calculation methods of their energy performances in several operation conditions. Typically, the CPV systems
electrical power is separately calculated or in terms of its temperature or concentration factor (C), but not simultaneously in
terms of both variables. In this paper, an Artifcial Neural Network model based on experimental data, linking electric power
of CPV system with Direct Normal Irradiance and Triple-Junction cell temperature for diferent C values, is developed.
Moreover, the model is also adopted to realize a feasibility analysis of point-focus CPV system used for diferent users:
residential building and agricultural livestock farm. The optimal number of modules is determined to maximize the Net
Present Value (NPV) of the investment. For the residential user, an optimal confguration of CPV system includes 16 modules,
providing a peak power of 3.1 kW and covering an area of 130 m2
. This confguration allows the maximization of NPV
value, reaching 15.9 k€, with DPB of 9.8 years. As for the agricultural livestock, 36 modules, with peak power of 7.0 kW
and covering an area of 292 m2
, allow the maximization of NPV value equal to 16.3 k€, with DPB of 10.2 years
Comparison of the Spherical Optics and Fresnel Lens Performance in a Point-Focus CPV System
No full textThe optical system is the component that more affects the performances of a Concentrating Photovoltaic (CPV) system. In this paper, a commonly used Fresnel lens and a less adopted spherical optics of the same diameter, are experimentally compared in a point-focus CPV system from an optical and an energy point of view. The spherical optics allows to reach the optical concentration factor and optical efficiency values equal respectively to 515 and 73%. These values are about three times higher with respect to the Fresnel lens, thus reducing the area of a CPV system with the same power output. Moreover, the spherical optics requires a lower accurate solar tracker with respect to the Fresnel lens, being the acceptance angle values equal respectively to 0.79° and 0.37°. The power and energy losses due to a solar tracking failure are also evaluated for both the optics. The concentration reached by the spherical optics allows also to increase the TJ cell temperature up to 65°C higher than the environmental temperature, and to obtain a cell electrical power equal about to 15 W. As for the Fresnel lens these values are much lower and equal respectively to about 40°C and 5 W. Moreover, the spherical mirror allows the electrical energy production for a longer time in case of a solar tracking failure
Energy analysis and numerical evaluation of the decanter centrifuge for wastewater management to allow a sustainable energy planning of the process
No full textThe decanter-centrifuge is widely used for dewatering and thickening of civil and industrial sludge. The latest generation decanters, both the bowl motors (main) and the screw (back-drive) are often driven by variable-frequency drives (VFD), with the back-drive able to recover the energy during braking. We created a decanter centrifuge energy model equipped with a braking recovery system during the sludge dewatering process, with the aim of identifying its optimal operating conditions for both energy consumption and product quality. Specific models at 15–20–25 m3 h−1 and various differentials speed (Δn) were used to derive a general model, then validated with experiments at 18–20 m3 h−1. Specific models used to identify the best operating conditions in terms of specific energy (e) and energy recovery (ERec) show that at 15–20–25 m3 h−1 the lowest energy consumptions were 1.88–1.76–1.57 kWh m−3, respectively, instead, ERec was 5.88–0.31–12.10 kW respectively, highlighting that a high recovery is not necessarily linked to an increased energy saving. The accuracy of these models was confirmed by high values of correlation coefficients R2 and very low Root Mean Square Errors (RMSE) in each case. The general model, extrapolated from the specific models, makes it possible to predict specific consumptions at different flow rates within the operating range of the decanter. This was validated with an experimental test at 18–20 m3 h−1 with R2 above 97 % and RMSE 2,59E-02 kWh m3. The dry matter content in the cake decreases when the Δn or the feed rate increases.In conclusion, the decanter centrifuge model could represent a useful tool for optimizing the sludge dehydration process
Carlo Perone Pacifico, a Mentor for Agricultural Economists
No full textCarlo Perone Pacifico died last November. After his post-graduate studies at the new-born Centro di specializzazione in Ricerche economico-agrarie di Portici, he went to Berkeley where he took his Master of Science degree. He was then called back to Portici as a researcher in the field of the Economics and Politics of Agricultural Markets. At the Centro he also had administrative responsibilities. In 1983 he went to Viterbo and started teaching in the new-born Faculty of Agriculture of the Tuscia University. Here he founded the Department of Agricultural Economics and Policy. During 25 years spent in this University, Carlo Perone dedicated great efforts to improving the functioning of the faculty, being Dean for 9 years, and indeed of the economic and cultural life of the province.Portici Centre, Tuscia University, Agricultural Markets, Common Agricultural Policy
Experimental and economic analysis of a concentrating photovoltaic system applied to users of increasing size
No full textThe costs of concentrating photovoltaic (CPV) and concentrating photovoltaic and thermal (CPV/T) systems are highly reduced in the last years because of their increasing diffusion. The unit power cost also depends on the plant size. Hence, the main aim of this paper is to analyze the feasibility of a CPV/T system adopted for users with increasing sizes located in Salerno (Italy): the house, the hotel, and the food industry. An experimental model was developed for an accurate evaluation of the electrical and thermal powers supplied by the CPV/T system when direct normal irradiation (DNI) and environmental temperature vary. A modular configuration of a line-focus CPV/T system was sized to match the electrical and thermal loads of each user. The current economic results, together with a forecast till the year 2025, were discussed. In 2025, for the same CPV system adopted for the domestic user, the net present value (NPVs) are expected to increase by 6.7% and 13% in pessimistic and optimistic scenarios, respectively, with reductions of its discounted payback period (DPBP) of 16% and 30%. For the same CPV systems adopted for the other two users, the NPVs are expected to increase by about 4.2% and 8.4% in pessimistic and optimistic scenarios, respectively, with decreases of its DPBP of 14% and 27%
La maturità di Alessandro Fei del Barbiere, in bilico tra Maniera e Riforma
No full textThis article studies the mature career of the Florentine painter Alessandro Fei del Barbiere (1537-1592), beginning with the rediscovery of the 'Ascension' altarpiece formerly in the Albizi Chapel in the destroyed church of San Pier Maggiore, Florence. Studying this painting and others recorded in 1584 by the biographer Raffaello Borghini, such as the two altarpieces for Santa Maria delle Grazie and the Madonna dell'Umiltà in Pistoia, the author reconstructs a body of works showing how in the 1580s Fei gradually went beyond the archaic style of his apprenticeship - he had been trained by Ridolfo del Ghirlandaio and Pierfrancesco Foschi, but was also marked by the Maniera of Vasari - evolving towards naturalism in both mimesis and pictorial handling. In Florence, his development partly parallels that of Santi di Tito and his circle, but Fei was also influenced by a probable sojourn during the early part of that decade in Rome, where he could have been inspired by Girolamo Muziano and the painters working for Pope Gregory XIII. Among other proposals, the author suggests that the artist was responsible for decorating the chancel of Fiesole Cathedral (c. 1584-1589), which consisted of an altarpiece, only rarely discussed by scholars, and a cycle of frescoes hitherto attributed to Nicodemo Ferrucci
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