1,720,987 research outputs found
Energy efficiency of photovoltaic panel
No full textThe need to increase the share of electricity produced from renewable resources has pushed the installation of photovoltaic systems. Solar sources in recent years have experienced strong growth both in terms of investments and installations. In fact, in 2018, solar energy had a global generation capacity of 43% compared to all other power generation technologies. In the coming years, the use of solar energy will grow rapidly, especially for use in different applications. Therefore, studying the behavior of photovoltaic panels and having a model that accurately describes their behavior is essential for the design of the system. Furthermore, increasing the efficiency of the panel in anomalous conditions such as defects, breaks or partial shading is essential. As described, the doctoral thesis is focused on increasing the efficiency of the panels, on the modeling of photovoltaic panels and on the preliminary study of the causes of loss of efficiency and power produced by finding solutions through monitoring systems and applications for reconfigurable panels. After the introduction of the photovoltaic panels, the thesis is followed by a chapter dedicated to mathematical modeling using an equivalent electric model of a photovoltaic panel. This chapter allows to describe the behavior of a photovoltaic panel under normal operating conditions and variable environmental conditions. From a preliminary review of the methods in the literature for the estimations of the parameters, a new method for the extraction of the parameters is proposed. This method starts from the data provided by the manufacturer in the datasheet of the panel and estimates the five parameters. These parameters are needed to model a panel with a single diode equivalent circuit. The proposed method was compared with some works in the literature and the error concerning the data provided by the manufacturer was evaluated A chapter follows on the modeling and simulation of photovoltaic panels through the PSpice environment. In the literature, there are various more or less complex PV Spice models. Some Spice models do not take into account irradiation and temperature variation significant for the design of electronic circuits to be connected to the photovoltaic panels. This proposed model can simulate a photovoltaic panel with temperature and solar radiation variation. With the proposed Spice model as a block is possible to simulate photovoltaic plants both at low power and high power and force partial shading conditions to understand their behavior. After the description of models for photovoltaic panels, the study on possible anomalies present in photovoltaic systems due to defects on the panels or breakages was presented. Thanks to the combination of thermography and electrical measurements for the reconstruction of the IV characteristic of the individual panels, it was possible to understand the various anomalies. Indeed, it is possible to estimate thresholds that will serve to understand if a panel is still good or a replacement is necessary. For this reason, the comparison between thermography and electrical measurements and simulations is provided. Furthermore, this study has allowed us to understand and calculate the annual efficiency loss of the panels and the percentage of voltage variation concerning the temperature not supplied by the manufacturer. The next chapter describes the study and design of an electronic system for monitoring photovoltaic panels connected to a plant. The monitoring of the single panels allows the recognition of possible anomalies and to identify the panel that is the cause. Usually, monitoring is done at the inverter or string level, which however does not allow the faulty panel to be identified in the event of anomalies. The proposed parameter extraction methods and Spice model were used for the design of the monitoring board. Finally, the last activity developed concerns the increase in power lost during partial shading
Effects of energy efficiency measures on building performance: an analysis in seven European cities
No full textThis work presents the energy performance analysis of an autarkic residential building, located in the
suburb of L’Aquila, in central Italy. The analysis is performed via a calibrated dynamic thermal model, carried out
with EnergyPlusTM engine coupled with DesignBuilder. The aim of this study is the further understanding of the
optimization margins of the energy self-sufficient building by considering different Energy Efficiency Measures
and the effects obtainable in different climatic conditions. Four Italian cities and three European capitals are
considered, in addition to different scenarios, characterized by various technological plants. In fact, a significant
difference between the high efficiency of the envelope, and the poor performance of the heating system was
observed. The results highlighted the remarkable energy performance optimization of the analyzed building,
although the effects of the Energy Efficiency Measures showed notable differences between colder and warmer climates
SPOF—Slave Powerlink on FPGA for Smart Sensors and Actuators Interfacing for Industry 4.0 Applications
Full text linkWe here present a new PLC-POWERLINK industrial solution for Industry 4.0 applications. The proposed solution provides the capability to separate the sensing functionality from the PLC-side, in demand for the reconfigurable FPGA implementation. In particular, we here provide a framework that supports the interfacing between the POWERLINK protocol and commonly used standards, such as I2C, SPI, and UART. This has been obtained by using a framework built around a soft IP-core Application Processor, which manages the interfacing with several POWERLINK slaves, able to support the data exchange with the POWERLINK Communication Processor. A practical application example and related implementation details are presented in the paper
Room and window geometry influence for daylight harvesting maximization – Effects on energy savings in an academic classroom
Full text linkLighting systems have a fundamental role for the overall buildings energy consumption. Therefore, remarkable efforts are required for optimizing the lighting systems energy use and for finding new daylight harvesting solutions. In this paper, the impacts on daylight harvesting provided by different room and window geometries and their effects on energy savings are presented. An academic classroom with only one window is chosen as case study and it is supposed that the window orientation is modified according to the four cardinal points. A climate-based approach was chosen for the multiple simulations, carried out via DIVA software, by assuming: square and rectangular classroom geometries with the same total area; square and rectangular window shapes having Window to Floor Ratios (WFRs) equal to 8% and 12%; two different dimmable lighting systems, in order to quantify the energy savings, by considering fluorescent and LED dimmable lamps. The daylight analysis, performed by evaluating both the Daylight Factor (DF) and the Daylight Autonomy (DA), showed that room and window geometries have high influence on daylight harvesting maximization, allowing remarkable energy savings (up to 48.5%) with respect to non-dimmable lighting system. In particular, the best energy result, equal to 467.5 kWh/yr, was obtained with rectangular room and window geometries coupled with LED lamps and WFR equal to 12%
Metodo ed apparato per la misura accurata dell'umidità delle strutture e di altri parametri ambientali
No full textA Low Cost Flexible Power Line Communication System
No full textThe present work focuses its attention on the definition of a home automation system based on power line communication. A low cost and non invasive system has been developed and tested with successful results. It is based on the Cypress CY8CPLC10, an integrated power line communication chip which embeds both a PHY modem and a network protocol stack. The information management and data generation processes are demanded to a microcontroller, in this first prototype, being implemented with a standard Arduino board. Combining the use of a microcontroller with a power line modem makes possible to manage sensors and actuators in the neighbors through the power grid and without modifying the electrical and network systems
A Low Cost Fully Integrable in a Standard CMOS Technology Portable System for the Assessment of Wind Conditions
No full textNowadays, the environmental meteorological monitoring is becoming a primary need in many fields of human activity. Continuous and accurate measurements are often required also in absence of local and fixed stations. This scenario leads to the development of low cost portable systems and to the design of innovative architectures, thanks to the availability of new technologies and sensors. The full system here proposed - easily integrable on a CMOS technology - is based on a hot wire anemometer, provided by Telecontrolli SME, and a suitable heater feedback that achieves, thanks to a dedicated algorithm, a novel portable solution with a robust design, without moving parts and small dimensions. It is suitable to operate up to 50°C and provides accurate wind speed and direction measurement
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