Search results for "photovoltaic"
showing 10 items of 646 documents
A Finite Difference Model of a PV-PCM System
2012
Abstract The performances of a photovoltaic panel (PV) are defined according to the “peak power” that identifies the maximum electric power supplied by the panel when it receives an insolation of 1 kW/m2 and the temperature of the cell is maintained at 25 °C. These conditions are only nominal since the solar radiation has a variable intensity and also the panel is subjected to thermal excursions; due to these reasons the real power efficiency of the panel is considerably lower than that obtainable in the nominal conditions. The study focused on assessing a method to reduce the peak temperatures of PV systems using Phase Change Materials (PCM). To this aim it was created a numerical model ca…
Reconfigurable electrical interconnection strategies for photovoltaic arrays: A review
2014
Non-uniform irradiance significantly decreases the power delivered by solar photovoltaic arrays. A promising technique for compensating these power losses relies on dynamically reconfiguring the electrical connections between photovoltaic modules. This paper presents the current state-of-the-art strategies for photovoltaic array reconfiguration in order to increase the power output under partial shading and mismatch conditions. The different approaches have been compared in terms of effectiveness of the control algorithms, monitored electrical and environmental variables, overall hardware complexity and specific features of each solution. Finally, the most challenging aspects of the reconfi…
Sustainable technologies for greenhouse systems
2020
The greenhouse cultivation system in European countries represents one of the most energy-intensive sectors in the agriculture and agro-industry sector. In this regard, renewable energies represent an innovative solution to reduce energy costs and environmental impacts. Both, the energy demands and the economic aspects are analyzed with regard to the main energy users, i.e.: heating and cooling systems, lighting and pumping for irrigation. This work considers the use of solar photovoltaic and thermal energy. The use of semi-closed greenhouses is also considered.
A sizing approach for stand-alone hybrid photovoltaic-wind-battery systems: A Sicilian case study
2018
Abstract Solar and wind energy are the two most available renewable energy resources in the world. In this paper, a high-resolution analysis that allows sizing a hybrid photovoltaic-wind turbine-battery banks has been carried out. The analysis aims to minimize the annualized cost of the systems satisfying two reliability constraints. The solution has been obtained numerically by means of an iterative technique. The decision variables are the photovoltaic area, wind turbine radius, and battery capacity. A high-resolution model, based on fuzzy logic inference system, has been developed to evaluate the number of active occupants and the domestic electricity consumption. In order to allow a mor…
Six-years-long effects of the Italian policies for photovoltaics on the pay-back period of grid-connected PV systems installed in urban contexts
2017
Abstract In this study the discounted pay-back (DPB) period of rooftop photovoltaic (PV) systems installed in urban contexts was investigated during the course of time with the aim of evaluating the effects of the different supporting policies enacted by the Italian government. The profitability of the investment in three Italian cities was observed from June 2010 to May 2016 by means of an exhaustive economic analysis based on the study of the variation of the costs and benefits during the lifetime of the investment. The analysis considered the disbursements for the PV system devices, maintenance and management, insurance, and wear of PV panels and inverters. Other significant parameters, …
Fabrication and electro-optical characterization of Ruthenium-based Dye-Sensitized Solar Cells
2015
In this paper, we measure the main photoelectrical parameters of Dye Sensitized Solar Cells (DSSCs) based on ruthenium complexes at different irradiance levels, incident wavelengths, temperatures and hours of light soaking
Experimental characterization of Ruthenium-based Dye Sensitized Solar Cells and study of light-soaking effect impact on performance
2016
In this paper, we present an experimental investigation on the performance of Ruthenium-based Dye Sensitized Solar Cells (DSSCs) at different irradiance levels, incident wavelengths and hours of illumination. In particular, the measurements have been aimed at studying the performance variation due to light soaking effect since this phenomenon has noteworthy practical implications, such as stability tests of DSSCs. Our results show that the short circuit current density, the open circuit voltage and the conversion efficiency η increase with the hours of light soaking. Finally, the observed phenomenon is reversible, and thus the performance decreases again when the cell is kept in the dark.
Anomální Ramanovy módy v teluridech
2021
[EN] Two anomalous broad bands are usually found in the Raman spectrum of bulk and 2D Te-based chalcogenides, which include binary compounds, like ZnTe, CdTe, HgTe, GaTe, GeTe, SnTe, PbTe, GeTe2, As2Te3, Sb2Te3, Bi2Te3, NiTe2, IrTe2, and TiTe2, as well as ternary compounds, like GaGeTe, SnSb2Te4, SnBi2Te4, and GeSb2Te5. Many different explanations have been proposed in the literature for the origin of the anomalous broad bands in tellurides, usually located between 119 and 145 cm(-1). They have been attributed to the intrinsic Raman modes of the sample, to oxidation of the sample, to the folding of Brillouin-edge modes onto the zone center, to the existence of a double resonance, like that …
Energy evaluation and life cycle assessment of an innovative building integrated technology: the smart window-luminescent solar concentrator
2022
Luminescent Solar Concentrators (LSC) represent one of the innovative and potentially most versatile technologies related to Building Integrated Photovoltaics (BIPV). The peculiarity of these devices lies in the fact that they can be integrated into the surface of the building to replace openings such as skylights or windows, thanks to their characteristic of being semi-transparent and of functioning both with direct and diffused radiation. Eni developed the own technology Eni Ray Plus® based on LSC and integrated it in a multifunctional smart window-LSC (SW-LSC) prototype. The device uses the energy produced by LSC modules to power an autonomous and passive shading system, exploiting irrad…
Effect of the linkage location in double branched organic dyes on the photovoltaic performance of DSSCs
2015
Two novel double branched D–π–A organic dyes (DB dyes) are synthesized to investigate the influence of the linkage location in DB dyes on the performance of dye-sensitized solar cells (DSSCs), where phenothiazine is introduced as a donor, thiophene–benzotriazole unit as the π-bridge and cyanoacrylic acid as the electron-acceptor. The photophysical, electrochemical and photovoltaic properties of the dyes are systematically investigated. The results show that the location of the linkage unit has a small effect on the physical and electrochemical properties of the dyes. However, when the dyes are applied in DSSCs, an obvious decline of short-circuit current (Jsc) and open-circuit voltage (Voc)…