Stefan Nebojsa Djordjevic

Mr. Stefan Nebojsa Djordjevic

Department of Physics, Faculty of Sciences and Mathematics, Niš, Serbia
orcid

Research Focus & Metrics

Academic Career Length

4Years (2023-Present)

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

Representative Publications

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24 April 2023 in Applied Sciences
Verified
Journal Article
Open access
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SDStefan Nebojsa Djordjevic
Stefan Nebojsa Djordjevic
LPLana Pantic
Lana Pantic
MKMarko Slobodan Krstic
Marko Slobodan Krstic
IMIvana Radonjić Mitić
Ivana Radonjić Mitić
MMMarko Mančić
Marko Mančić
APAleksandar Pantic
Aleksandar Pantic
Electrical energy generation in solar modules is mainly limited by the increase in their temperature, and a heat removal process plays an important role. The main goal of the experiment was to keep the temperature of the cooled module below 47 °C through a series of the five short cooling and heating cycles and to determine the changes in the solar module output power during the cooling process with 96% ethyl alcohol. The optimal duration of the cooling cycles was determined to be between 3–6 min and for the heating process, it was 4–5 min. During the heating and cooling cycles the temperature of the cooled module did not exceed 42.1 °C. At the end of five active cooling cycles the temperature difference of 22.6 °C was achieved. The biggest difference in power between the cooled and uncooled module was 4.9%. The solar module efficiency was increased by 3.2%. It was concluded that alcohol, due to its evaporative losses, is not a viable cooling agent for solar modules. Nevertheless, it can serve as a potent additive in both active and passive cooling systems to augment the output power of solar modules.

1 January 2025 in Thermal Science
Verified
Journal Article
Open access
PDF file
SDStefan Nebojsa Djordjevic
Stefan Nebojsa Djordjevic
MKMarko S. Krstić
Marko S. Krstić
LPLana S. Pantić
Lana S. Pantić
IMIvana Radonjić Mitić
Ivana Radonjić Mitić
MMMarko Mančić
Marko Mančić
MVMarko V.
Marko V.
The efficiency of PV panels is significantly influenced by the temperature of the cells, as higher temperatures reduce electrical power output, degrade performance, and shorten the panel?s lifespan. This study investigates the effectiveness of a closed-loop cooling system applied to the backside of a PV panel to enhance its output characteristics. The cooling system circulated approximately 20 L of water at a constant flow rate of 70 Lph. The results demonstrated a substantial 41.75% increase in power output, with the maximum efficiency achieved at peak cooling. Using real weather data recorded during the experiment, the temperature distribution across the panel layers was modeled using the ANSYS FLUENT 2023 R1 software package. The simulation and experimental results showed a maximum temperature difference of 1.6?C between the measured and simulated values. The cooled panel maintained an average temperature of 26.65?C, with a minimum of 16.7?C, compared to an uncooled panel?s higher temperatures. The system effectively reduced the temperature of the front side of the panel by up to 23.1?C, enhancing the overall energy output. These findings confirm that cooling PV panels from the back is an efficient method to reduce temperature and increase panel efficiency. Detailed simulations and analyses enable insight into PVT system performance and forecasting of production under various climatic conditions.

3 June 2024
Verified
Conference Paper
Closed access
LPLana Pantić
Lana Pantić
IMIvana Radonjić Mitić
Ivana Radonjić Mitić
SDStefan Nebojsa Djordjevic
Stefan Nebojsa Djordjevic
MKMarko Slobodan Krstic
Marko Slobodan Krstic
DRDragan Radivojević
Dragan Radivojević
MPMilutin Petronijevic
Milutin Petronijevic
This paper presents an analysis of the field performances of south-facing vertical solar module in Nis, Serbia is presented. Electrical parameters, backside temperature and weather parameters were continuously measured and 12 sunny days, predominantly occurring in the middle of each month throughout the year, were selected. The daily change of the solar radiation intensity, maximum power, module temperature and electrical efficiency were analyzed, to assess the feasibility of using vertical PV modules in Niš. Based on the results, it can be concluded that, south-facing solar module generates most of electrical energy in March and September, as well as one month before and after each. From November until the end of February, local weather conditions have negative impact on electricity production. The electrical efficiency of the module exhibits an opposite trend of daily change in summer and winter months, with the maximum value in summer months and the minimum in winter corresponding to solar noon. Vertical modules are ideal for urban environments for which space-efficient solutions are required, as they contribute to sustainable electricity generation.

27 June 2024 in Energy and Buildings
Verified
Journal Article
Closed access
IRIvana Radonjić
Ivana Radonjić
LPLana Pantić
Lana Pantić
MPMilutin Petronijevic
Milutin Petronijevic
SDStefan Nebojsa Djordjevic
Stefan Nebojsa Djordjevic
MKMarko Slobodan Krstic
Marko Slobodan Krstic
Plamen TsankovPlamen Tsankov
Plamen Tsankov

3 June 2024
Verified
Conference Paper
Closed access
KKKristina Kojic
Kristina Kojic
IMIvana Radonjić Mitić
Ivana Radonjić Mitić
LPLana Pantic
Lana Pantic
SDStefan Nebojsa Djordjevic
Stefan Nebojsa Djordjevic
MKMarko Slobodan Krstic
Marko Slobodan Krstic
MPMilutin Petronijevic
Milutin Petronijevic
Throughout their utilization, photovoltaic (PV) modules can be partially or completely shaded by trees, buildings, and other objects in their vicinity. Consequently, shaded PV modules receive lower solar radiation intensity, thus PV modules performances and output power are reduced. This paper gives the results of an experimental study of the soft shading influence of on the current-voltage and power-voltage characteristics of monocrystalline and polycrystalline PV modules. Power reduction of the monocrystalline PV module due to vertical and horizontal soft shading was in the range of 15% to 18%. Power reduction of the polycrystalline PV module for vertical and horizontal shading was in the range of 27% to 30%.

3 June 2024
Verified
Conference Paper
Closed access
KKKristina Kojic
Kristina Kojic
IMIvana Radonjić Mitić
Ivana Radonjić Mitić
LPLana Pantic
Lana Pantic
SDStefan Nebojsa Djordjevic
Stefan Nebojsa Djordjevic
MKMarko Slobodan Krstic
Marko Slobodan Krstic
MPMilutin Petronijevic
Milutin Petronijevic
Throughout their utilization, photovoltaic (PV) modules can be partially or completely shaded by trees, buildings, and other objects in their vicinity. Consequently, shaded PV modules receive lower solar radiation intensity, thus PV modules performances and output power are reduced. This paper gives the results of an experimental study of the soft shading influence of on the current-voltage and power-voltage characteristics of monocrystalline and polycrystalline PV modules. Power reduction of the monocrystalline PV module due to vertical and horizontal soft shading was in the range of 15% to 18%. Power reduction of the polycrystalline PV module for vertical and horizontal shading was in the range of 27% to 30%.