1. Comparative analysis of batteries for photovoltaic systems : bachelor's thesisKristina Gočanin, 2023, undergraduate thesis Abstract: Renewable energies represent unlimited power sources that are significantly reducing greenhouse emissions. The possibilities and advantages of abundantly available solar energy are immense. However, some challenges are preventing solar energy from reaching its full potential regarding its efficiency and energy storage. Therefore, the main focus of this thesis is on electrochemical storage systems. The aim is to compare the currently leading technology – Li-ion battery to the most recent breakthrough in storage systems – the solid-state battery. The thesis includes a comparative analysis of the mentioned technologies, as well as the theoretical part that introduces solar energy and photovoltaic systems with their main components.
Keywords: photovoltaic system, energy storage, analysis, Li-ion battery, solid-state battery
Published in DKUM: 30.01.2024; Views: 449; Downloads: 43
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3. Simplified method for analyzing the availability of rooftop photovoltaic potentialPrimož Mavsar, Klemen Sredenšek, Bojan Štumberger, Miralem Hadžiselimović, Sebastijan Seme, 2019, original scientific article Abstract: This paper presents a new simplified method for analyzing the availability of photovoltaic potential on roofs. Photovoltaic systems on roofs are widespread as they represent a sustainable and safe investment and, therefore, a means of energy self-suffciency. With the growth of photovoltaic systems, it is also crucial to correctly evaluate their global effciency. Thus, this paper presents a comparison between known methods for estimating the photovoltaic potential (as physical, geographic and technical contributions) on a roof and proposes a new simplified method, that takes into account the economic potential of a building that already has installed a photovoltaic system. The measured values of generated electricity of the photovoltaic system were compared with calculated photovoltaic potential. In general, the annual physical, geographic, technical and economic potentials were 1273.7, 1253.8, 14.2 MWh, and 279.1 Wh, respectively. The analysis of all four potentials is essential for further understanding of the sustainable and safe investment in photovoltaic systems.
Keywords: photovoltaic system, rooftop photovoltaic potential, economic potential, light detection and ranging, LiDAR
Published in DKUM: 05.12.2023; Views: 382; Downloads: 15
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4. Analysis of photovoltaic system with battery storage in winter periodJan Lokar, Peter Virtič, 2019, published scientific conference contribution Abstract: Energy sources as a solar, wind and water energy are used in production of electrical energy. Their biggest advantage is that they are renewable and they are sustainable. On the other hand, production from renewable energy sources is limited by environmental conditions. Production of photovoltaic systems are dependent on solar radiation, temperature, incidence angle, shadowing and other variable quantities. That is why designing of photovoltaic system is complex. In this paper a photovoltaic system production analysis and consumption analysis in residential house are presented. With real measured data the consumption and production are compared and energy balance equations, battery charge and discharge model are defined and behaviour of battery storage system through the one day are analysed. In addition, the reactive energy production and consumption are also analysed.
Keywords: photovoltaic system, battery storage
Published in DKUM: 05.12.2023; Views: 260; Downloads: 15
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5. Efficiency of laser-shaped photovoltaic cellsEwa Korzeniewska, Mariusz Tomczyk, Łukasz Pietrzak, Miralem Hadžiselimović, Bojan Štumberger, Klemen Sredenšek, Sebastijan Seme, 2020, original scientific article Abstract: The main aim of this paper is to analyze the influence of laser shaping of the photovoltaic cell based on its efficiency. The authors described both process of the monocrystalline photovoltaic cell manufacturing, its efficiency, and the possibilities of usage in architecture and the process of creating the photovoltaic cells of unconventional shapes by using laser technology. A method for cutting photovoltaic cells using a fiber laser was presented as well as the parameters of the laser cutting process. The described method allows cutting the massively produced silicon cells according to the predetermined trajectory. Using the proposed process parameters, satisfactory cutting edge quality, and negligible impact of the laser beam on changes in the structure of the photovoltaic cell active layers were achieved. In each cycle of structure cutting, only a small part of the material is removed (from 1 to 2 mikro), and depending on the thickness, the process is repeated from 50 to 300 times. It has been shown that the efficiency of the modified cells depends on the ratio of their surface area to the laser cutting line.
Keywords: photovoltaic cells, efficiency, photovoltaic cell modification, laser modification, silicon cells
Published in DKUM: 15.11.2023; Views: 384; Downloads: 16
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6. Solar photovoltaic tracking systems for electricity generation : a reviewSebastijan Seme, Bojan Štumberger, Miralem Hadžiselimović, Klemen Sredenšek, 2020, review article Abstract: This paper presents a thorough review of state-of-the-art research and literature in the field of photovoltaic tracking systems for the production of electrical energy. A review of the literature is performed mainly for the field of solar photovoltaic tracking systems, which gives this paper the necessary foundation. Solar systems can be roughly divided into three fields: the generation of thermal energy (solar collectors), the generation of electrical energy (photovoltaic systems), and the generation of electrical energy/thermal energy (hybrid systems). The development of photovoltaic systems began in the mid-19th century, followed shortly by research in the field of tracking systems. With the development of tracking systems, di%erent types of tracking systems, drives, designs, and tracking strategies were also defined. This paper presents a comprehensive overview of photovoltaic tracking systems, as well as the latest studies that have been done in recent years. The review will be supplemented with a factual presentation of the tracking systems used at the Institute of Energy Technology of the University of Maribor.
Keywords: solar energy, photovoltaic tracking system, tracking strategies, drive system, degree of freedom
Published in DKUM: 15.11.2023; Views: 434; Downloads: 29
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7. Determination of produced and consumed electricity of a residential building using a graphical user interfaceEva Simonič, Iztok Brinovar, Sebastijan Seme, Klemen Sredenšek, 2021, professional article Abstract: The primary objective of this paper is to present a graphical user interface for the calculation of electricity produced by a photovoltaic system and electricity consumed by a heat pump. The produced electricity is determined by a multi-year average of measurements of the global and diffuse power density of solar radiation for several places in Slovenia, while consumed electricity is determined based on the required heat for heating a residential building and domestic water. The calculation of produced and consumed electricity is validated by measurements on a real system. The developed graphical user interface enables simple user inputs of the photovoltaic system, heat pump, and the considered residential building, and provides a comprehensive technical analysis for installing both systems at the same location.
Keywords: graphical user interface, photovoltaic system, heat pump, production of electricity, consumption of electricity
Published in DKUM: 13.11.2023; Views: 269; Downloads: 12
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8. Static model of temperature distribution in a photovoltaic moduleKlemen Sredenšek, Sebastijan Seme, Gorazd Hren, 2021, original scientific article Abstract: The primary objective of this paper is to present a static model for calculating the temperature distribution in a photovoltaic module using the finite element method. The paper presents in more detail the theoretical background of solar radiation, heat transfer, and the finite element method. The results of the static model are evaluated using temperature measurements of a photovoltaic model, which were performed at the Institute of Energy Technology, Faculty of Energy Technology, University of Maribor. The results of the regression analysis show a good concurrence between the measured and modelled values of the temperature of the photovoltaic module, especially on days with a higher share of the direct component of solar radiation.
Keywords: photovoltaic module, temperature distribution, heat transfer, finite element method
Published in DKUM: 13.11.2023; Views: 269; Downloads: 7
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9. Experimental validation of a dynamic photovoltaic/thermal collector model in combination with a thermal energy storage tankKlemen Sredenšek, Sebastijan Seme, Bojan Štumberger, Miralem Hadžiselimović, Amor Chowdhury, Zdravko Praunseis, 2021, original scientific article Abstract: The primary objective of this paper is to present a dynamic photovoltaic/thermal collector model in combination with a thermal energy storage tank. The added value of the proposed model is the use and integration of existing dynamic models for describing the entire photovoltaic/thermal system. The presented model was validated using measurements on the experimental system located at the Institute of Energy Technology, Faculty of Energy Technology, University of Maribor. The validation was carried out based on three different weather conditions—sunny, cloudy, and overcast. The validation results were evaluated using the normalized root mean square error and mean absolute percentage error for the temperature and output power of the photovoltaic/thermal collector and the temperature of the thermal energy storage tank. The model results concurred with the measurements, as the average mean absolute percentage error values for the temperature and output power of the photovoltaic/thermal collector and thermal energy storage tank temperature were 5.82%, 1.51%, and 7.58% respectively.
Keywords: photovoltaic/thermal collector, thermal energy storage tank, dynamic modeling, temperature distribution, output power
Published in DKUM: 13.11.2023; Views: 312; Downloads: 14
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10. Proportional-integral controllers performance of a grid-connected solar PV system with particle swarm optimization and Ziegler-Nichols tuning methodKlemen Deželak, Peter Braciník, Klemen Sredenšek, Sebastijan Seme, 2021, original scientific article Abstract: This paper deals with photovoltaic (PV) power plant modeling and its integration into the medium-voltage distribution network. Apart from solar cells, a simulation model includes a boost converter, voltage-oriented controller and LCL filter. The main emphasis is given to the comparison of two optimization methods-particle swarm optimization (PSO) and the Ziegler-Nichols (ZN) tuning method, approaches that are used for the parameters of Proportional-Integral (PI) controllers determination. A PI controller is commonly used because of its performance, but it is limited in its effectiveness if there is a change in the parameters of the system. In our case, the aforementioned change is caused by switching the feeders of the distribution network from an open-loop to a closedloop arrangement. The simulation results have claimed the superiority of the PSO algorithm, while the classical ZN tuning method is acceptable in a limited area of operation.
Keywords: photovoltaic power plant, optimization, PI controllers, distribution system
Published in DKUM: 10.11.2023; Views: 341; Downloads: 13
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