Examinando por Autor "Tina, Giuseppe Marco"
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Ítem A new approach to analyse from monitored data the performance, matching capability and grid usage of large Rooftop Photovoltaic systems. Case of study: Photovoltaic system of 1.05 MW installed at the campus of University of Jaén(Elsevier, 2025) Muñoz-Rodríguez, Francisco José; Gómez-Vidal, Pedro; Fernández-Carrasco, Juan Ignacio; Tina, Giuseppe Marco; Jiménez-Castillo, GabinoRooftop photovoltaic installations highlight their potential to meet a significant portion of urban electricity demand. These systems range from a few kW in residential areas to hundreds of kW in large Rooftop PV systems in commercial and industrial settings. The latter, which may include several inverters or arrays with different orientations and inclinations, require a proper analysis to assess the potential of this technology and to ensure the design objectives. This paper presents a methodology for analysing from monitored data large Rooftop PV systems, focusing on performance, self-consumption and grid usage. The approach is scalable, applicable at the inverter, individual Rooftop PV and global system levels. New key parameters defined include weighted system irradiation (HI,weighted) and weighted system reference yield (Yr,weighted), which account for different array orientations and inclinations. The methodology is validated using a 1.05 MW system at the University of Jaén with monitored data over a year. Results indicate subsystem and system PR values above 0.83 and a system Capacity Factor of 0.19, confirming a proper performance. Annual self-consumption and self-sufficiency indices of 97.5 % and 17.7 %, respectively, and a solar hour self-sufficiency of 27.7 % reveal minimal energy export and substantial potential to meet the university’s electricity demand.Ítem Effect of electrical operating conditions on thermal behavior of PV modules: Numerical and experimental analysis(Elsevier, 2025) Osama, Amr; Tina, Giuseppe Marco; Gagliano, Antonio; Jiménez-Castillo, Gabino; Muñoz-Rodríguez, Francisco JoséThe rapid growth of photovoltaic (PV) energy has the potential to transform the global energy landscape. However, the intermittent nature of solar power presents significant challenges to grid integration, such as overgeneration and curtailment. Consequently, PV systems may operate at points other than the maximum power point (MPP). Monitoring the thermal behavior of photovoltaic systems is critical due to its impact on productivity and system health. Most studies focus on meteorological variables, often overlooking the influence of electrical operating states on thermal performance. Thus the objective is to evaluate the accuracy of existing thermal models from the literature and widely used specialized software tools—alongside their commonly cited coefficients against different electrical operating status (EOS). This study investigates the thermal behavior of PV modules under different EOS: short-circuited (PVset-1), open-circuited (PVset-2), and operating at MPP (PVset-3). The experiment was conducted over four months at Jaén University campus in Spain. Results showed the short-circuited module's temperature was 6.90 °C higher, and the open-circuited module's temperature was 3.67 °C higher than the MPP module. Thermographic investigations revealed multiple hotspots in the short-circuited set. These hotspots can severely impact the module's long-term reliability and efficiency. The analysis of thermal models considering these operating states indicated an overestimation of the MPP module's temperature. However, the Keddouda model demonstrated high accuracy potential, with an average deviation of less than 3.4 %, particularly at high irradiance levels. These findings highlight the necessity of considering EOS in thermal models to enhance the accuracy and reliability of PV system performance assessments.Ítem Effects of smart meter time resolution when analyzing photovoltaic self-consumption system on a daily and annual basis(Elsevier, 2021-02) Jiménez-Castillo, Gabino; Rus-Casas, Catalina; Tina, Giuseppe Marco; Muñoz-Rodríguez, Francisco JoséThe management of photovoltaic self-consumption systems is based mainly on updating energetic parameters such as generation and household power consumption connected via smart devices. The expected rapid increasing volume of data collected with different time resolutions is surely a topic that deserves great attention. The choice of a proper recording interval should balance the amount of monitored data and a proper energy analysis in order not only to take effective and timely decisions but also to help this technology to be more efficient. In the literature, only specific nominal array powers for annual reporting period or an array power range for daily reporting period have been considered. In this context, the error, when matching photovoltaic generation and household power consumption profiles considering different recording intervals (1, 10, 15, 30 and 60 min) and different reporting periods (daily and annual), will be estimated as a function of the array power (up to 10 kWp) for five households and a resident’s association. Results depend on the reporting periods and it may be advisable to use 1 min and 10 min of recording intervals in order to estimate performance metrics in this type of system for a daily and annual basis, respectively.Ítem Impacts of Array Orientation and Tilt Angles for Photovoltaic Self-Sufficiency and Self-Consumption Indices in Olive Mills in Spain(MDPI, 2020-02-18) Jiménez-Castillo, Gabino; Muñoz-Rodríguez, Francisco José; Martinez-Calahorro, Antonio Javier; Tina, Giuseppe Marco; Rus-Casas, CatalinaOlive mills are extensive in the Mediterranean Basin, and Spain constitutes approximately 45% of global production. The industrial sector faces a new energetic paradigm where distributed generation provided by small renewable energy sources may reduce the dependence from fossil energy sources as well as avoid energy distribution losses. Photovoltaic self-consumption systems can play an important role in confronting this challenge due to their modularity and their decreasing cost. Most of self-sufficiency energy studies are focused on building sector and discussions about the idiosyncrasy of industrial load profiles, and their matching capability with photovoltaic generation profiles can be scarcely found. This work analyzes the potential of photovoltaic self-consumption systems as a function of the array power, array tilt, and orientation angles to face the electric consumption in olive mills. Different recording intervals and reporting periods are considered. Results show that a self-sufficiency index of 40% may be achieved on olive harvest basis. Moreover, due to the load profile particularities, percentage error lower than 1.6% has been found when considering a recording interval of 60 min when matching the olive load consumption and photovoltaic generation profiles. Chosen array tilt and orientation angles may be key parameters to maximize the self-sufficiency index.Ítem Monitoring PWM signals in stand-alone photovoltaic systems(Elsevier, 2019-02) Jiménez-Castillo, Gabino; Muñoz-Rodríguez, Francisco José; Rus-Casas , Catalina; Casa-Hernández, Jesús; Tina, Giuseppe MarcoThe performance of stand-alone photovoltaic (SAPV) systems can be evaluated by monitoring them in the field using data acquisition systems (DASs). Most SAPV systems use battery charge controllers with pulse width modulation (PWM) to regulate the current into the battery. The PWM signals generated by battery charge controllers imply monitoring challenges due to the complexity of this type of signal. In this sense, the aim of this paper is to develop a new and simple monitoring technique for SAPV systems which can estimate the signals provided by a PWM battery charge controller, thus avoiding expensive DASs, simultaneous sampling and the huge amount of collected data. The estimation of PWM signal parameters, such as the duty factor (df) or high and low states, shows high accuracy, with the mean absolute percentage error lower than 1.4%, a mean relative error within 1.4%, and the coefficient of determination higher than 0.9. Furthermore, the proposed technique may easily be used for other electrical devices where PWM is employed.Ítem Nonlinear and multivariate regression models of current and voltage at maximum power point of bifacial photovoltaic strings(Elsevier, 2024-02) Mannino, Gaetano; Tina, Giuseppe Marco; Jiménez-Castillo, Gabino; Cacciato, Mario; Bizzarri, Fabrizio; Canino, AndreaThe bifacial photovoltaic (PV) modules are able to convert the irradiance that hits both the front and the back side of the modules into electrical energy, this allows to increase the output power compared to monofacial modules. However, the mathematical models used for traditional PV modules do not consider the contribution of rear irradiance, even recent works deal with the modeling of the rear irradiance influence on bPV power output. In the present work some empirical models capable of estimating the current and voltage at maximum power point conditions are unveiled; the models consider only the front irradiance, as monofacial PV modules, or the back irradiance through the concept of equivalent irradiance and module temperature. In addition, some modifications to the current and voltage models have been proposed. In all cases, the optimal parameters of the models are obtained starting from a dataset of experimental data acquired from a string of bifacial photovoltaic modules installed in Catania (Italy). The PV plant under study was monitored for an entire year, thus allowing the use of data acquired in different weather conditions. The method description includes the filtering of the input signals and the searching method of the empirical coefficients in order to estimate the current and voltage at the maximum power point (MPP) for bifacial photovoltaic modules.