Reliability Prediction of Smart Maximum Power Point Converter for PV Applications

The photovoltaic generation distribution supports new energetic scenario development (Net Zero Energy Cluster and DC microgrids). In this context, smart maximum power point (SMPPT) converter represents innovative systems that are able to monitor operating conditions, communicate energetic production data and signal a fault condition. The Smart Maximum Power Point role becomes crucial, and critical aspects such as efficiency and reliability have to be taken into account from the beginning of the design. In this chapter, the idea is to review different reliability prediction models for electronic components focusing on the military ones with the analysis of a case study related to a Smart Maximum Power Point converter in photovoltaic applications

A radial basis function neural network based approach for the electrical characteristics estimation of a photovoltaic module

The design process of photovoltaic (PV) modules can be greatly enhanced by using advanced and accurate models in order to predict accurately their electrical output behavior. The main aim of this paper is to investigate the application of an advanced neural network based model of a module to improve the accuracy of the predicted output I--V and P--V curves and to keep in account the change of all the parameters at different operating conditions. Radial basis function neural networks (RBFNN) are here utilized to predict the output characteristic of a commercial PV module, by reading only the data of solar irradiation and temperature. A lot of available experimental data were used for the training of the RBFNN, and a backpropagation algorithm was employed. Simulation and experimental validation is reported

A joint approach for strategic bidding of a microgrid in energy and spinning reserve markets

n the electricity market, short-term operation is organized in day-ahead and real-time stages. The two stages that are performed in different time intervals have reciprocal effects on each other. The paper shows the strategy of a microgrid that participates to both day-ahead energy and spinning reserve market. It is supposed that microgrid is managed by a prosumer, a decision maker who manages distributed energy sources, storage units, Information and Communication Technologies (ICT) elements, and loads involved in the grid. The strategy is formulated considering that all decisions about the amount of power to sell in both markets and the price links to the offer, must be taken contextually and at the same time, that is through a joint approach. In order to develop an optimal bidding strategy for energy markets, prosumer implements a nonlinear mixed integer optimization model: in this way, by aggregating and coordinating various distributed energy sources, including renewable energy sources, micro-turbines–electricity power plants, combined heat and power plants, heat production plants (boilers), and energy storage systems, prosumer is able to optimally allocate the capacities for energy and spinning reserve market and maximize its revenues from different markets. Moreover, it is considered that both generators and loads can take part in the reserve market. The demand participation happens through both shiftable and curtailable loads. Case studies based on microgrid with various distributed energy sources demonstrate the market behavior of the prosumer using the proposed bidding model

Salinas e lo Steri: un nuovo museo per una nuova città

Attraverso lo studio di due singolari planimetrie inedite e non datate viene fatta luce su una pagina sconosciuta della museologia palermitana: la proposta, mai attuata, di Antonino Salinas, appoggiata anche da Giuseppe Fiorelli e da Paolo Boselli, di trasferire tra il 1887 ed il 1910 tutte le raccolte archeologiche, di arte medievale e moderna dai locali dell’ex convento dei padri Filippini all’Olivella nel complesso medievale di Palazzo Chiaramonte o Steri. L’infelice scelta post-unitaria di destinare l’ex convento a sede del Museo di Palermo, l’Esposizione Nazionale del 1891/1892 ed il “taglio” della via Roma, praticato nei primi anni del ‘900 per la realizzazione della nuova grande arteria cittadina, sono i moventi, che sollecitano gli attori della vicenda a sollevare la questione. La ricerca documentale, che descrive gli eventi sino al 1932, svela molte delle dinamiche e delle problematiche inerenti ai fatti come la possibile costituzione di un nuovo polo museale, una suggestiva area urbana riqualificata, che risulta quasi un intero quartiere dedicato ai musei. Il nuovo progetto espositivo del Salinas è in linea di continuità con la ben nota idea dell’archeologo palermitano di celebrare la “storia delle arti di tutta la Sicilia” ed allo stesso tempo anticipa alcune delle scelte espositive, che saranno adottate in seguito dal Marconi e dall’Accascina: un unicum tra i coevi musei nazionali della penisola.Through the study of two singular unpublished and undated floor plans, light is shed on a unknown page of palermitan museology: the proposal, never implemented, by Antonino Salinas, supported also by Giuseppe Fiorelli and Paolo Boselli, to transfer all the archaeological, medieval and modern art collections between 1887 and 1910 from the spaces of the former convent of the Filippini fathers to the Olivella in the medieval complex of Palazzo Chiaramonte or Steri. The unfortunate choice of post-unification destiny the former convent which houses the Museum of Palermo, the National Exhibition of 1891/1892 and the “taglio” of via Roma, carried out in the early 1900s for the construction of the new major city thoroughfare, are the reasons which pushed the actors of the story to raise the question. Documentary research, which describes the events up to 1932, reveals many of the dynamics and problems relating to the facts such as the possible establishment of a new museum center, a suggestive redeveloped urban area, that there is almost an entire district dedicated to museums. The new exhibition project of the Salinas is in a line of continuity with the well-known idea of the palermitan archaeologist to celebrate the “history of the arts of the whole Sicily” and at the same time anticipates some of the exhibition choices, which will be adopted later by Marconi and Accascina: unique among the contemporary national museums of the peninsula

a new approach for the dimensioning of an air conditioning system with cold thermal energy storage

Abstract In this work, a new approach for the design of air conditioning systems with cold thermal energy storage is described and tested, considering the case study represented by a vapor-compression chiller, coupled with a chilled water storage system, producing cooling for a small multi-apartment building situated in Italy. In the present approach, at the aim of limiting shut-downs and start-ups of the chiller, which involve inefficiencies during transients, and can lead to a drastic reduction of the equipment lifetime, the nominal power of the chiller, and the amount of cooling to be stored are first estimated in a pre-design phase. Successively, the outputs of the pre-design are used to fix the size of the cold storage tank, and to set up the numerical simulation of the cold thermal energy storage system. Finally, the results of the numerical simulation of the cold storage system are used to evaluate the effective size of the chiller. Both the pre-design and the numerical simulations of the cold storage systems have been done by means of home-made numerical tool realized with Simulink. In the paper, the specifications relative to the operational strategy are explored, and the analytical models used for the numerical simulation of the cold storage system relative to the Italian case study are reported in detail. Finally, the results of the pre-design, and of the cold storage system simulations relative to the case study are presented and discussed. The results relative to the Italian case study demonstrates the effectiveness of the present approach in limiting the number of shut-downs and start-ups of the chiller. The present approach can represent a useful tool for the economic optimization of the design of air conditioning systems

analysis of a biomass fired cchp system considering different design configurations

Abstract This work aims to present the results of an energetic and economic analysis of a biomass fueled CCHP system operating according to different design configurations. The investigated system consists of a biomass-fueled cogeneration unit, an absorption chiller, a thermal energy storage system and a cold one, providing electricity, heat and cooling to an Italian cluster of buildings. For each simulated configuration, the feasible investment cost of the CHP unit is evaluated considering the economic savings obtained with respect to separate generation of electricity, heat and cooling. The best configuration from the economic point of view is indicated, and the incidence of the variation of the absorption chiller and storage systems sizes on the feasible investment cost of the CHP unit is evaluated and discussed as well. Results indicate that the most influencing parameter is represented by the absorption chiller power

Photovoltaics in Net Zero Energy Buildings and Clusters: Enabling the Smart City Operation☆

Abstract From 2012 to comply with the ED 2010/31/EU and its recasts, all new buildings will perform as Nearly Zero Energy Buildings (NearlyZEBs). Buildings are going to be transformed through a careful design into energy generation systems, and the conventional, centralized system of energy generation is going to be replaced by a "web" of energy generation systems. Photovoltaics (PV) seems to be one of the most suitable energy generation technologies for enabling this change, thanks to its "fair" cost, technical features, and multifunctional use in the building's envelope, as well as in the urban environment. PV will be an indispensable technology for Net Zero Energy Buildings (NetZEBs), with the consequence of being a kind of "ubiquitous" technology, also suitable for added uses than the traditional ones. For example: in addition to the multifunctional use in the building's envelope, it might offer advanced services for improving the efficiency and participation in the city processes. A multidisciplinary investigation on possible ways for PV and NetZEBs to change the future urban scenario is proposed, focusing on design, energy management and technological issues to support a Smart City (SC) vision

experimental validation of a tool for the numerical simulation of a commercial hot water storage tank

Abstract This work focuses on the experimental validation of a numerical tool realized to simulate a commercial hot water storage tank. The tool implements unsteady 1D models to simulate the temporal evolution of the temperature field inside the hot water storage tank, and the one relative to the heat transfer fluid flowing through the immersed coil heat exchanger. It has been implemented by means of the Simulink tool of Matlab. The first part of the paper is dedicated to the description of the indoor experimental facility used to realize the experimental test. Successively, the analytical models, and the numerical schemes and algorithms used to perform the numerical simulations are described. Finally, the results of the experimental validation of the tool, accomplished by comparing the experimental temperature profiles inside the tank, and the measured temperatures at the coil heat exchanger exit section over the entire experimental test duration, with the numerical results obtained from simulations performed using different correlations for the evaluation of the heat transfer rate between the tank water and the heat transfer fluid through the coil, are reported and discussed

Transient Analysis of a Solar Domestic Hot Water System Using Two Different Solvers

Abstract In the present work the unsteady numerical simulation of a solar domestic hot water (DHW) system composed of two flat plate collectors, a water tank for heat storage, and a coil heat exchanger is addressed. The simulations have been performed using two different solvers, namely a home-made code written in Matlab, and TRNSYS 17. In the first part of the paper, the analytical models used in the Matlab code, and the TRNSYS case are reported in detail. Successively, the results of the simulations realized by means of the two solvers are presented and compared