Lana Pantic

As the temperature of photovoltaic panels rises, a drop in electrical conversion efficiency and output power is unavoidable. Therefore, a simple and low-cost cooling solution is needed - one that requires little or no maintenance and consumes no electricity. In this paper, we experimentally and numerically investigated passive cooling of photovoltaic panels using heat sinks of different geometries. Our experiments showed that these heat sinks reduce the average back-side temperature of the cooled panel by 13.6°C compared to a reference panel. They also increased the open-circuit voltage by 0.27 V relative to the reference. We also performed numerical simulations using Ansys Fluent 2025 R2. The simulated temperatures agreed well with the experimental data - the average difference was less than 1°C (approximately 1.9% relative difference). The simulations gave us a good insight into heat dissipation from the heat sinks. They revealed better cooling due to proper fin spacing, but also a limitation caused by the small contact area between the heat sink and the photovoltaic panel. These results confirm that passive cooling with aluminum heat sinks is a good method for improving photovoltaic panel performance, while the developed numerical model represents an accurate tool for heat sink design optimization.

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.

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%.

This study offers experimental testing of commercial and laboratory inverters, utilized in a laboratory prototype of an urban microgrid. Operation of grid inverters supplied by PV arrays in urban environments, encounters challenges such as partial shading and soiling. Emulation of the current-voltage characteristics of PV arrays enables repeated and reliable testing of inverter operation under irregular supply conditions. It has been shown that finding the maximum power point can be challenging under conditions of partial shading and soiling. Additionally, meeting the grid quality standards for the delivered power represents a challenge. Satisfying these requirements can be achieved through careful design of LCL filters at inverter output terminals, but further improvement can be achieved only through an adequate selection of the primary controller. To further improve the quality of grid currents, the possibility of applying innovative control algorithms has been demonstrated for laboratory inverters. Application of sliding mode controllers, besides ensuring system robustness, can prevent overshoots and fault responses from the current protection circuit by introducing a specific anti-windup structure.

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%.

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.

To estimate PV potential of Bijeljina, PVGIS and SOLARGIS databases were used. The results showed that Bijeljina municipality has an average daily PV power potential of 3.50 kWh/kWp, thus belonging to areas with the favorable mid-range PV power potential values. Average levelized cost of electricity is $0.12/kWh, consequently making PV technologies in Bijeljina also economically competitive with conventional power-generating sources. In the light of the rapid development of photovoltaic technology, this paper gives a critical review of previous studies and suggests that the application of PV technologies has become even more attractive. High-efficiency PV modules and grid inverters were tested on examples of roof-mounted PV systems and ground-mounted PV system using specialized PVSYST software. Comparison of the obtained results with previous studies gave a clear picture with advantages of these new solutions, and further support for PV technologies utilization.

Soiling is a term used to describe the deposition of dust (dirt) on the solar modules, which reduces the amount of solar radiation that reaches the solar cells. This can cause a more difficult operation of the entire photovoltaic system and therefore generation of less electric energy. This paper presents the results of the influence of various pollutants commonly found in the air (carbon, calcium carbonate ? CaCO3, and soil particles) on the energy efficiency of solar modules. Scanning electron microscope investigation of carbon powder, CaCO3, and soil particles which were applied to solar modules showed that the particles of carbon and CaCO3 are similar in size, while the space between the particles through which the light can pass, is smaller in carbon than in CaCO3. Dimensions of soil particles are different, and the space between the soil particles through which the light can pass is similar to CaCO3. Solar radiation more easily reaches the surface of solar modules soiled by CaCO3 and soil particles than the surface of the solar modules soiled by carbon. The efficiency of the module soiled by carbon on average decreases by 37.6%, the efficiency of the module soiled by CaCO3 by 6.7%, and the efficiency of the module soiled by soil particles by 6.8%, as compared to the clean solar module. The greatest influence on reducing the energy efficiency of solar modules by soiling exerts carbon, and the influence of CaCO3 and soil particles is similar.

The aim of this paper was to investigate the influence of solar radiation intensity, ambient temperature, wind speed and solar module temperature on the modules physical characteristics, in local climate conditions and for all seasons in Nis, Serbia. Twelve sunny days, for each month of the year, from the period September 2014 - June 2016 were selected. During each day meteorological parameters, solar module temperature and solar module output parameters were measured. The highest values of solar radiation intensity, ambient temperature and solar module temperature were measured in summer months, while the lowest values were in winter months. The maximal values of the output power were measured in summer months due to the high values of solar radiation intensity on the solar modules surface. A negative impact of high solar module temperature on the open circuit voltage, the output power, the fill factor and the efficiency was observed. In the winter months the local climatic conditions and air pollution have an adverse impact on the solar module efficiency and lead to a noticeable reduction of the efficiency.