Yazar "Bayrak, Fatih" seçeneğine göre listele

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    A bibliometric and performance evaluation of nano-PCM-integrated photovoltaic panels: Energy, exergy, environmental and sustainability perspectives
    (Pergamon-Elsevier Science Ltd, 2024) Bestas, Sukru; Aktas, Ilter Sahin; Bayrak, Fatih
    One of the major problems regarding PV panels is the decline in power output and efficiency whilst exposed to temperatures surpassing their operating temperature. In order to preclude such undesirable situation, it is imperative to cool PV panels and provide a uniform distribution of surface temperatures during the implementation of the cooling method. Thermal management can be achieved at the surface temperatures of PV panels by utilizing phase change materials (PCMs). In this study, along with PCM, the potential of enhancing output parameters by decreasing the surface temperature of PV panels with the addition of nanoparticles (Al 2 O 3 ) at different concentrations (0.05%, 0.1%, and 0.15% w/v) to PCM (RT35) is examined. The study compared five systems: a reference PV panel (PV), PV panel cooled with PCM without nanoparticles (PV PCM-0 ), and PV panels with PCM containing different concentrations of nanoparticles (PV PCM-0.05 , PV PCM-0.1 , and PV PCM-0.15 ). Among the five different systems, the PV panel containing 0.15% w/v nanoparticles (referred to as PV PCM-0.15 ) demonstrated the most effective cooling capability. Moreover, the PV PCM-0.15 system provided the highest performance with a 19.49% increase in panel power output. PV systems have average energy and exergy efficiency values of 9.06% and 3.79% for PV panel, 9.60% and 5.15% for PV PCM-0 , 9.70% and 5.12% for PV PCM-0.05 , 10.28% and 6.01% for PV PCM-0.1 , and 10.44% and 7.29% for PV PCM-0.15 . Upon analyzing the sustainability metrics, it was determined that the PV PCM-0.15 system was more energy and environmentally sustainable than the others.
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    Effects of different fin parameters on temperature and efficiency for cooling of photovoltaic panels under natural convection
    (Pergamon-Elsevier Science Ltd, 2019) Bayrak, Fatih; Oztop, Hakan F.; Selimefendigil, Fatih
    The photovoltaic panels are one of the most efficient energy systems that generate electricity by absorbing the solar radiation. Nevertheless, when the sun's rays are converted to electricity, a high amount of waste heat is generated. Therefore, the efficiency of photovoltaic (PV) panels needs to be studied to minimize the amount of waste heat. There is a non-linear relationship between the temperature, the current and the voltage values produced by the PV panels. In the present study, the performance of 75 W PV panels with polycrystalline cell structure under Elazig, Turkey climatic conditions were experimentally investigated. The system performances such as temperature, power and efficiencies were analyzed by applying different fin parameters (length, sequences) to PV panels. The aluminum fins were applied with 10 different configurations as given by A1-A10. The cell temperatures, output powers, power loss ratios and energy-exergy efficiencies were calculated based on measurements of the experimental study. It was observed that the temperature did not distributed homogeneously on the PV panel. In terms of the efficiency, the fins are designed as staggered array and the 7 cm x 20 cm dimensions showed the best results. The highest energy and exergy efficiencies values of the finned panels (A5) were calculated as 11.55%, and 10.91%, respectively.
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    Effects of static and dynamic shading on thermodynamic and electrical performance for photovoltaic panels
    (Pergamon-Elsevier Science Ltd, 2020) Bayrak, Fatih; Oztop, Hakan F.
    An experimental examination has been performed on the performance assessment of different shading shapes on photovoltaic panels by using energy-exergy analysis methods in this study. The problem is important due to decreasing of performance of PV panel with shading effect. A non-transparent material and powder were used for static shading while the time-varying shading effect of a chimney for dynamic shading was applied on to the system. Novelty of the work is to use diagonal shading on energy and exergy efficiency. Moreover, thermal camera technique was used to observe the effects of temperature distribution as a novel technique for PV panels. The photovoltaic panel was kept outside for one month in terms of dusty shading. For other static shading, artificial shadows of three different triangular shapes (40 * 40 cm for Case I, 36 * 60 cm for Case II and 60 * 36 cm for Case III) were created. The energy and exergy efficiencies of all systems under the same solar radiation were compared. The Case I-III under the same solar radiation was imaged by using a thermal camera and the effect of shading on photovoltaic panels and hot spot formation were examined. The results showed that the highest energy efficiency value was found to be 10.54% for the reference panel, 9.70% for the dusty panel, 4.16% for Case I, 4.27% for Case II and approximately zero for Case III. In the panel of dynamic shading, the lowest and the highest efficiency values were found as 0.86% and 10.27%, respectively.
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    Energy, Exergy and Sustainability Indicators of Photovoltaic Panel Cooling under Forced Convection
    (2022) Bayrak, Fatih
    Photovoltaic (PV) panels generate some of their energy as waste heat while converting solar radiation into electricity. This heat in photovoltaic panels adversely affects the output parameters of the panels. For this reason, there are many studies on cooling of PV panels in the literature. In this experimental study, waste heat was removed by placing DC fans with different numbers and different consumption power on 80 W monocrystalline panels. According to the results obtained from the experiments, while the net power of the reference panel was 62.42W, the net power of the E4 system (with 4 fans and the consumption power of the fans was 10W) was measured as 64.1W. The highest exergy efficiency and sustainability index values among all systems were also obtained from the E4 system.
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    Enerji Depolamalı Bir Boruda Nanoakışkan Kullanımının Isıl Performansa Etkisinin Sayısal Olarak İncelenmesi
    (2021) Bakır, Eda; Işık, Erdem; Uçar, Aynur; Bayrak, Fatih
    Teknolojideki gelişmeler göz önüne alındığında, yüksek verimli elektronik cihazlardan beklenen verimlilik ve güvenirliğe ulaşmak için iyi bir termal performansa sahip yeni yaklaşımlar ve soğutuculara ihtiyaç duyulmaktadır. Bu çalışmada aynı hidrolik çapa, kanal uzunluğuna ve kesit geometrisine sahip alüminyum boru kullanılmıştır. Sistemin ısı transfer hızını arttırmak için; boru içerisinde su, %1 ve %2 derişimlerine sahip Al2O3/su nanoakışkanları, boru dış yüzeyinde ise 5mm kalınlığında RT25HC faz değiştiren maddesi (FDM) kullanılmıştır.Alüminyum boru içerisinden geçirilen akışkanlar dört farklı hız ve dört farklı Reynolds sayısında ANSYS 20.2 paket programı kullanılarak analiz edilmiştir.Elde edilen sonuçlara göre her bir akışkan için kütlesel erime oranı ve Nusselt sayısı hesaplanmıştır. Çalışmada elde edilen sonuçlar incelendiğinde en iyi Nusselt ve sıvı oranına Reynolds 1500 ve%2 Al2O3/su’da ulaşılmıştır. Tüm soğutucu akışkanlar için akışkan hızının artmasıyla soğutucu akışkanların kütlesel erime oranının ve Nusselt sayısının arttığı sonucuna ulaşılmıştır.
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    Experimental analysis and dynamic modeling of a photovoltaic module with porous fins
    (Pergamon-Elsevier Science Ltd, 2018) Selimefendigil, Fatih; Bayrak, Fatih; Oztop, Hakan F.
    In this study, experimental analysis and performance predictions of solar photovoltaic (PV) module equipped with porous fins were performed. The experimental setup was tested in Technology Faculty of Firat University, Elazig of Turkey which is located at 36 and 42 North latitudes. The PV module was oriented facing south and tilted to an angle of 36 with respect to the horizontal in order to maximize the solar radiation incident on the glass cover. Experimental analysis was conducted for configurations where PV module is equipped with porous metal foams. A multi-input multi-output dynamic system based on artificial neural networks was obtained for the PV configuration with and without fin by using the measured data (ambient temperature, PV panels back surface temperatures, current, voltage, radiation and wind velocity) from the experimental test rig. It was observed that adding porous fins to the PV module results in performance enhancements. The developed mathematical model based on dynamic neural networks can be used for further development and performance predictions of these systems. (C) 2018 Elsevier Ltd. All rights reserved.
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    Experimental Analysis of PV/T Collectors Assisted with PCM for Off-Grid Domestic Applications
    (2021) Bakır, Eda; Bayrak, Fatih; Öztop, Hakan Fehmi
    An experimental study was carried out to examine the efficiency of solar energy in photovoltaic thermal collectors (PV/T) with energy storage. A photovoltaic thermal collector was used to generate both electrical energy and hot water. The effects of inclination angle of PV/T collectors on power, temperature, energy and exergy values were investigated. Also, effects of cellular shading are tested and discussed. PV/T was compared with the conventional PV/T collector by adding phase change material (PCM) for one of the collectors. In addition, the effect of different shading conditions (small, medium and large circle) on the power and hot water output of the PV/T collector at optimum slope angle were investigated. It is found that 7 ºC temperature differences are occurred in the hot water outlet between the PV/T collector and the PV/T-PCM collector. The highest energy efficiencies of PV/T-PCM collectors are obtained as 73.26%, 84.70% and 68.96% for slope angle 25º, 30º and 35º, respectively. The highest exergy efficiencies of shaded collectors are obtained as 11.92% for PV/T and 23.38% for PV/T-PCM.
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    Experimental study for the application of different cooling techniques in photovoltaic (PV) panels
    (Pergamon-Elsevier Science Ltd, 2020) Bayrak, Fatih; Oztop, Hakan F.; Selimefendigil, Fatih
    This article contains the experimental investigations of different cooling methods used for photovoltaic (PV) panels. Phase change material (PCM), thermoelectric (FE) and aluminum fins were chosen as the cooling methods. The CaCl2 center dot 6H(2)O is chosen as one of the PCM which is widely used in the cooling of PVs and the other is the PCM with melting temperature above the surface temperature of the PV panel. By using TE material in different numbers (6, 8 and 12) and aluminum fins in different layouts, surface temperatures and output powers of PV panels were compared. It is observed that the PCM which is not chosen appropriately has insulation feature in the PV panel and enhances the temperature of the panel and decreases the output power. When the most successful cooling methods were tested under the same environmental conditions, PV with fin system produced the highest power generation of 47.88 W while PV with PCM and TEM produced the lowest power generation of 44.26 W.
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    Poroz Kanatçık İlaveli Hava Isıtmalı PV/T Kolektörünün Sürdürülebilirlik İndeksi ve Termodinamik Analizi
    (2021) Bayrak, Fatih
    Fotovoltaik panellerin ve güneş kolektörlerinin ayrı ayrı kullanılması hem maliyeti hem de kapladıkları alanı artırmaktadır. Bu yüzden araştırmacıları bir sistemden hem ısı hem de elektrik üretmeye yönlendirmiştir. Bu deneysel çalışmada, yeni tip kanatçıklı hava ısıtmalı fotovoltaik/termal (PV/T) kolektör tasarlanmış ve karşılaştırılmalı olarak test edilmiştir. Deneylerde, kanatçıklı ve kanatçıksız PV/T kolektörlere doğal taşınım (DT) ve zorlanmış taşınım (m_1=0.01 kg/s ve m_2=0.015 kg/s) uygulanmıştır. Tüm sistemlerin termodinamik analizi ve ekserji veriminin bir fonksiyonu olan sürdürülebilirlik indeksi (SI) incelenmiştir. Elde edilen sonuçlara göre kütlesel debinin artması ve kanatçık entegre edilmesi PV/T sisteminin çıkış gücüne, elektriksel enerjisine ve ekserjisine pozitif etki etmiştir. Sistemdeki en düşük çıkış gücü kanatçıksız ve doğal taşınımda (M1) 26.84W, en yüksek çıkış gücü kanatçıklı ve zorlanmış taşınımda (M6) 37.40W’tır. Tüm PV/T kolektörleri karşılaştırıldığında en yüksek genel ekserji verimi %20.48 ile doğal taşınımlı ve kanatçıklı M4 kolektörü olmuştur. Ekserji veriminin bir fonksiyonu olan sürdürülebilirlik indeks (SI) değerleri kanatçıklı sistemlerde daha yüksektir.