Klemen Sredenšek

Prof. Dr. Klemen Sredenšek

University of Maribor, Faculty of Energy Technology
orcid

Research Focus & Metrics

Academic Career Length

8Years (2019-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
15 August 2020 in Energies
Verified
Journal Article
Open access
PDF file
Sebastijan SemeSebastijan Seme
Sebastijan Seme
BSBojan Stumberger
Bojan Stumberger
MHMiralem Hadžiselimović
Miralem Hadžiselimović
Klemen SredenšekKlemen Sredenšek
Klemen Sredenšek
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, different 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.

27 April 2021 in Energies
Verified
Journal Article
Open access
PDF file
KDKlemen Deželak
Klemen Deželak
PBPeter Bracinik
Peter Bracinik
Klemen SredenšekKlemen Sredenšek
Klemen Sredenšek
Sebastijan SemeSebastijan Seme
Sebastijan Seme
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 closed-loop 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.

6 November 2019 in Energies
Verified
Journal Article
Open access
PDF file
PMPrimož Mavsar
Primož Mavsar
Klemen SredenšekKlemen Sredenšek
Klemen Sredenšek
BSBojan Stumberger
Bojan Stumberger
MHMiralem Hadžiselimović
Miralem Hadžiselimović
Sebastijan SemeSebastijan Seme
Sebastijan Seme
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-sufficiency. With the growth of photovoltaic systems, it is also crucial to correctly evaluate their global efficiency. 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.

11 September 2020 in Energies
Verified
Journal Article
Open access
PDF file
Ewa KorzeniewskaEwa Korzeniewska
Ewa Korzeniewska
MTMariusz Tomczyk
Mariusz Tomczyk
LPLukasz Pietrzak
Lukasz Pietrzak
MHMiralem Hadžiselimović
Miralem Hadžiselimović
BSBojan Stumberger
Bojan Stumberger
Sebastijan SemeSebastijan Seme
Sebastijan Seme
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 μm), 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.

7 June 2021 in Applied Sciences
Verified
Journal Article
Open access
PDF file
Klemen SredenšekKlemen Sredenšek
Klemen Sredenšek
BSBojan Stumberger
Bojan Stumberger
MHMiralem Hadžiselimović
Miralem Hadžiselimović
Sebastijan SemeSebastijan Seme
Sebastijan Seme
KDKlemen Deželak
Klemen Deželak
An operating temperature of the photovoltaic (PV) module greatly affects performance and its lifetime. Therefore, it is essential to evaluate operating temperature of the photovoltaic module in different weather conditions and how it affects its performance. The primary objective of this paper is to present a dynamic thermo-electric model for determining the temperature and output power of the photovoltaic module. The presented model is validated with field measurement at the Institute of Energy Technology, Faculty of Energy Technology, University of Maribor, Slovenia. The presented model was compared with other models in different weather conditions, such as clear, cloudy and overcast. The evaluation was performed for the operating temperature and output power of the photovoltaic module using Root-Mean-Square-Error (RMSE) and Mean-Absolute-Error (MAE). The average RMSE and MAE values are 1.75 °C and 1.14 °C for the thermal part and 20.34 W and 10.97 W for the electrical part.

14 July 2023 in Energies
Verified
Journal Article
Open access
PDF file
KDKlemen Deželak
Klemen Deželak
Klemen SredenšekKlemen Sredenšek
Klemen Sredenšek
Sebastijan SemeSebastijan Seme
Sebastijan Seme
The widespread adoption of electric vehicles poses certain challenges to the distribution grid, which refers to the network of power lines, transformers, and other infrastructure that delivers electricity from power plants to consumers. This higher demand can strain the distribution grid, particularly in areas with a high concentration of electric vehicles. Grid operators need to ensure that the grid infrastructure can handle this additional load and prevent overloading and consequences in terms of additional losses. As part of the task, a methodology was developed for the assessment of the electricity consumption of battery electric vehicles in Slovenia. The approach used for the calculation includes the number of electric cars, average consumption, distance travelled and efficiency of the system. Additionally, the results of the modelling approach for an integrated distribution grid model in terms of steady-state simulations are presented. The regular situation of the power losses within the distribution grid is managed together with an optimal result. In this sense, an application of the particle swarm optimisation-based strategy is suggested to minimise reliance on grid systems.