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    Energy and exergy analysis of a vertical solar air heater with nano-enhanced absorber coating and perforated baffles
    (Pergamon-Elsevier Science Ltd, 2022) Khanlari, Ataollah; Tuncer, Azim Dogus; Sozen, Adnan; Aytac, Ipek; Ciftci, Erdem; Variyenli, Halil Ibrahim
    In this work, the effect of applying nano-enhanced absorber coating on the energetic and exergetic performance of an unglazed vertical solar air heating system has been analyzed numerically and experimentally. In the first step of the research, various configurations of vertical solar air heaters including hollow, baffled and perforated baffled systems have been surveyed by using computational fluid dynamics. According to the numerically obtained findings, the system with perforated baffles gave the best performance metrics. In this regard, two heating systems with perforated baffles have been manufactured. One of the system was painted with a regular matt black paint while CuO nano-embedded black paint applied to the other solar heater. Fabricated heaters have been experimentally surveyed at three different flow rates. Thermal efficiency values for the heaters with and without nanoparticles were found between 58.10-76.22% and 54.96-72.05%, respectively. Applying nano-embedded coating increased the exergy efficiency in the range of 9.25-10.58%. In addition, maximum deviation of numerically and experimentally attained outlet temperature values was calculated as 4.74%. Moreover, general findings of this research showed the successful utilization of nano-enhanced absorber coating. (C) 2022 Elsevier Ltd. All rights reserved.
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    Experimental and numerical analysis of a grooved hybrid photovoltaic-thermal solar drying system
    (Pergamon-Elsevier Science Ltd, 2023) Tuncer, Azim Dogus; Khanlari, Ataollah; Afshari, Faraz; Sozen, Adnan; Ciftci, Erdem; Kusun, Baris; Sahinkesen, Istemihan
    Photovoltaic-thermal (PVT) systems are sustainable applications that allows to produce thermal and electrical energies simultaneously. In this work, a sustainable solar drying system that contains a modified PVT-air collector has been designed, numerically analyzed, manufactured and tested. In the first step of this study, four different PVT collector configurations have been numerically analyzed in order to develop a new hybrid PVT drying system. According to the numerically obtained results, outlet temperature of the PVT collector with grooved absorber, spherical turbulators and baffle configurations was higher than the outlet temperature of the unmodified collector as 15.77 %. This promising PVT collector was then fabricated and integrated with a drying chamber. The manufactured hybrid drying system has been tested under various air flow rates. The experimental findings illustrated that the average thermal efficiency and overall exergy efficiency of the PVT collector varied between 61.32 and 77.49 % and 10.65-11.17 %, respectively. In addition, mean exergy efficiency of the drying chamber was found in the range of 59.16-68.31 %. Average sustainability index values of the collector and the drying chamber was obtained between the ranges of 1.12-1.14 and 3.74-5.82, respectively. Moreover, payback period of the dryer varied between 2.98 and 3.51 years according to the economic analysis.
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    Öğe
    PASSIVE THERMAL MANAGEMENT OF PHOTOVOLTAIC PANEL BY USING PHASE CHANGE MATERIAL-FILLED ALUMINUM CANS: AN EXPERIMENTAL STUDY
    (Begell House Inc, 2022) Tuncer, Azim Dogus; Khanlari, Ataollah; Aytac, Ipek; Ciftci, Erdem; Sozen, Adnan; Variyenli, Halil Ibrahim
    In the recent years, researches are focused on improving the efficiency of photovoltaic (PV) panels by cooling panel surface utilizing different methods. In this work, paraffin wax-filled aluminum beverage cans have been utilized to improve the performance of photovoltaic panels. The main aims of this study are reutilizing waste materials in solar systems and increasing the performance of a PV panel by employing an unconventional approach. Modified and unmodified PV panels have been experimentally investigated simultaneously to observe and compare their performances. Experimentally attained outcomes showed that electrical efficiency was upgraded from 70.69% to 72.60%. Moreover, normalized power output efficiency was (round as 61.72% and 71.56%, respectively, for unmodified and modified PV systems. In addition to the electrical performance investigation, an exergy analysis has been performed and mean exergy efficiency values for conventional and modified PV panels were found as 2.26% and 5.73%, respectively. General outcomes of this study showed successful utilization of paraffin wax -filled aluminum cans as a thermal management and efficiency improvement technique in photovoltaic systems.