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- MakaleAçık Erişim2024Scopus SJRQ4OUTDOOR DEGRADATION ANALYSES OF SIX DIFFERENT AGED PHOTOVOLTAIC MODULE TECHNOLOGIES UNDER THE ARID-STEPPE CLIMATE CONDITION
Cantürk, Zeynep; Özden, Talat; Akinoglu, Bulent G.
Outdoor tests of photovoltaics module are crucial both for marketing and for research and technological developments. The electric generation performance and their degradation rates and lifetime are also related to different climatic conditions of the regions. In this work, the outdoor tests are carried out for six different photovoltaic (PV) modules under Arid-steppe Climate condition of Ankara, Türkiye. Their degradation rates are calculated by using linear regression (LR) and year on year (YOY) methods. The comparison between LR and YOY are carried out and with the other performed studies of different regions of world. In addition, it is investigated that how effective the climatic conditions on daily degradation rates. The results obtained are as follows: Mono-Si and Hetero-junction Silicon (HIT) cell modules degradation rates of 0.71/1.56 %/year and 0.84 %/year are respectively obtained by LR method and 0.57/0.90 %/year and 0.85%/year are respectively by YOY method. The degradation rates for Cupper Indium Selenide (CIS), Cupper Indium Gallium Selenide (CIGS) and microcrystalline Silicon/Amorphous Silicon (µc-Si/a-Si) modules have 1.73/1.49 %/year, 11.55/9.52 %/year and 1.48 %/year for LR method and 1.28/1.12 %/year, 9.94/9.53 %/year and 0.99 %/year for YOY method are obtained respectively. It is also obtained for the Polycrystalline Silicon Modules as 1.20/1.86 %/year degradation rates by LR method and 0.79/1.88 %/year degradation rates by YOY method.
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İncele - MakaleAçık Erişim2020Scopus SJRQ1Dynamic thermal modelling of PV performance and effect of heat capacity on the module temperature
Tuncel, B.; Ozden, T.; Balog, R. S.; Akinoglu, B. G.
One of the main weaknesses of Si-based Photovoltaic (PV) solar modules is the sensitivity of their efficiency to module (cell) temperature. Especially in locations with long hot seasons, the efficiency loss of PVs due to high temperatures should be considered carefully. Thermal modelling is a method to predict the performance of a PV module using essentially the 1st law of thermodynamics and available data. In this paper, a transient thermal model is described, which considers hourly meteorological data, including wind speed and direction, module parameters, and locational information. In transient analysis, the heat capacity value of PV panel is required, but it is not a parameter specified in the manufacturer's datasheet. Experiments on the heat capacity of PV modules are missing in the literature. The thermal model provides verified performance analysis for a poly-c-Si PV module installed in Ankara, Turkey, with a calculated heat capacity value. And a sensitivity analysis for the heat capacity of the transient thermal model is performed. It is found that the model results are almost invariant under changing module heat capacity values.
AtıfScopus39WoS27OpenAlex41İncele - MakaleAçık Erişim2019Scopus SJRQ2Preliminary investigations on two different procedures to calculate the efficiency and performance ratio of PV modules
Ozden, T.; Akinoglu, B.G.
Short- and long-term outdoor performances of the photovoltaic (PV) modules are extremely important in reaching their economic viabilities. Such information is very valuable for the investors, customers and researchers of PV technologies. Two different procedures are possible, and both are used by many researchers. However, to the best of our knowledge, there is no comparative investigation to evaluate these two procedures. One of the methods uses instantaneous I–V curves of PV modules taken in a specified instant of time, while the others simply use the integrated energy values of the input and the yield of PV modules. In fact, both have advantages and disadvantages. In the present work, we outlined the advantages and disadvantages of both methods and compared them using the data of two different cell-type modules which are installed at GÜNAM’s outdoor test facility. In the analysis, the data that we used are taken under the same outdoor test conditions and ambient weather conditions. The outcomes of these preliminary analyses can be summarized as follows: (1) The procedure that uses instantaneous I–V curves seems dependent on the specified time intervals and ambient weather conditions at that instant; (2) accordingly, we will propose how to determine an optimal time interval to reach better performance results; (3) using the integrated values, we achieved the variations in performances with different integration time periods; (4) preliminary comparisons of these two procedures resulted in key conclusions on performance and degradation calculations of PV modules.
AtıfScopus4WoS2OpenAlex4İncele - BildiriAçık Erişim2018Thermal modeling and verification of pv module temperature and energy yield using outdoor measurements for Ankara, Turkey
Tuncel, Bilge; Akinoglu, Bulent G.; Ozden, Talat; Balog, Robert S.
Ankara is in the Central Anatolia region of Turkey where the climate is dry-continental with an annual solar insolation of around 1750 kWh/m 2 . In the transition to renewable energy, detailed analyses are required to ensure effective and economic utilization of the available solar resource. An essential part of these analyses is to calculate expected energy yield. For photovoltaic (PV) systems, this includes the effect of temperature on the PV efficiency, which determines the power yield of the PV modules. In this study, a first-principles thermal modeling approach is improved by adding the speed and direction of wind across the PV module into a forced convection term as well as including the temperature dependency of the module conversion efficiency. The analytical model is based on the principle of conservation of energy and uses meteorological data that are readily available from most state meteorological services. The mathematical analysis is suitable to predict the performance of a proposed PV installation without the time and expense of installing and monitoring a pilot system. The mathematical model is compared against measured data from the METU-GUNAM Outdoor Test Facility in Ankara to validate the methodology. Preliminary analyses showed that the model performs well especially during sunrise and sunsets shoulders of the diurnal cycle with a deviation of only a few W/m 2 for the electrical power yield and about 2°C for the module temperature. However, these deviations could become as large as 12 W/m 2 and 8°C at solar noon which suggests that the model still requires further improvement. In general, this error was found to be less that obtained by using basic explicit correlation methods and offers the advantage that it can be used for other geographical environments for which insolation and meteorological data is available without needing to construct a test-site.
AtıfScopus6WoS4OpenAlex6İncele - BildiriAçık Erişim2018Determining photovoltaic module performance and comparisons
Karaveli, Abdullah Bugrahan; Ozden, Talat; Akinoglu, Bulent G.
Knowing electricity production potential of a photovoltaic (PV) system prior to installation is very beneficial for the investor to see the feasibility of the investment. There are three procedures that can be followed to calculate the potential electricity production of any system under different conditions. These are installation of sample systems and gathering data over time, the use of some databases/software programs to reach the performances and developing new model/methodology to make these estimations. It is obvious that installation of PV systems everywhere is neither technically nor economically conceivable. On the other hand, global software programs may not reflect local conditions to calculations. Consequently, there is a need to develop methodology that is able to derive location specific equations and coefficients and make accurate estimations. Its accuracy can be controlled by validating the results for some locations with the measured values from already installed PV power plants (PV PP). So, in this study we initially develop a methodology to calculate efficiency and electricity production performance of some modules for Ankara and compare the results with the measured values owing to the system installed on the roof of the Middle East Technical University Solar Energy Research Center (METU GUNAM) in Ankara/Turkey. The methodology initially calculates solar irradiation falling on the modules that is the input. Then the performance of the module is calculated by using developed methodology. There are also some online software programs to calculate the performances, such as EU PVGIS and PV WATTS. We analyzed and used these software programs and compare their results with the results of newly developed methodology. As proven through mean-bias error (MBE), root-mean-square error (RMSE) and mean absolute error (MAE) statistical comparison methods, the methodology of this study has given the most accurate results.
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