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    Determination of optimum tilt angle of the solar collector and evaluation of the position of the existing buildings in terms of solar potential
    (Taylor & Francis Ltd, 2021) Sevik, Seyfi; Kocer, Abdulkadir; Ince, Huseyin; Tombus, Fazli Engin
    This study aims to determine the optimum tilt angle of the solar collector or PV for the province of corum, Turkey, and evaluate the existing 2019 building stocks in ten neighborhoods in terms of solar potential. The optimum collector tilt angle was obtained between 15 degrees and 56 degrees for six-month periods, it was calculated as 63 degrees, 24 degrees, 7 degrees, and 49 degrees for seasonal (winter, spring, summer, autumn) periods, respectively, and according to these values, the optimum solar radiation values were found for tilt angles. The annual optimum tilt angle for corum was found to be 34 degrees +/- 1; however, it was calculated that the optimum tilt angles during the year could vary between 1 degrees and 67 degrees. These results show that positioning the solar collectors/PVs at the optimum tilt angle, adjusting the tilt angle once a month or at least twice a year, or using solar tracking systems provide significant efficiency gains for optimum benefit. Based on the calculations made with azimuth angles, it was determined that 60% of the sampling buildings were positioned to benefit from sunlight during the day, and 10% of them are partially positioned, and thus, these buildings contribute to decarbonization. For this reason, it has been determined that the existing building stocks in corum province are highly suitable for low-cost roof installations and the construction of future buildings according to the locations determined in this study will increase thermal comfort. Although this study is mainly focused on local interest, it can be adapted to the general.
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    Effect of channel and fin geometries on a trapeze plate-fin heat sink performance
    (Sage Publications Ltd, 2021) Ozdilli, Ozgur; Sevik, Seyfi
    This study aims to achieve a minimum base temperature (or junction temperature) and hence better thermal performance. Trapezoidal curved plate-fin heat sink with dolphin fins and rectangular channel (Model-1) and trapezoidal curved plate-fin heat sink with dolphin fins, cut corner, and rectangular channel (Model-2) were designed and compared with a standard plate-fin heat sink. The effects of fins on the airflow and heat transfer in designed plate-fin heat sinks have been investigated numerically. The numeric results show that the use of fins and small changes in geometry significantly improve the heat transfer rate. Outcomes of the study showed 44-51% and 57-62% convective heat transfer enhancement compared with a standard plate-fin heat sink, without any overall mass augmentation, in Model-1 and Model-2, respectively. The presence of dolphin fins reduces the thermal resistance by up to 30%, which contributes to the overall thermal enhancement of the designed plate-fin heat sinks. Simulation results show that increasing the fins in areas close to the heat source and reducing the non-working areas significantly influence the thermal performance of heat sinks. The results also show that the trapeze plate-fin heat sinks with the different channel-fin geometries are superior to the standard trapeze plate-fin heat sink in thermal performance.
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    Evaluation of comparative combustion, performance, and emission of soybean-based alternative biodiesel fuel blends in a CI engine
    (Pergamon-Elsevier Science Ltd, 2020) Serac, Mehmet Resit; Aydin, Selman; Yilmaz, Adem; Sevik, Seyfi
    In this study, engine tests lead the studies on using diesel fuel (ultra-low sulfur diesel fuel, ULSD), soybased biodiesel and diesel blends. Performance, combustion and exhaust emission values obtained as ULSD and biofuel blends are presented under load of 3.6 kW, 7.2 kW and 10.8 kW and constant engine speed of 1500 rpm in a diesel engine power generator and compared with ULSD. The maximum increment in break specific fuel consumption (BSFC) is observed at 3.61cW with SOB20 fuel as about 8% compared to ULSD. Although the BSFC of soy-based biodiesel is high on low loads compared to the ULSD, both types of fuel gave almost identical results. The maximum increment of BTE compared to diesel fuel is occurred as 3.1% when the engine fueled with SOB20 fuel at 10.8 kW. All biodiesel blends are almost the same efficiency as diesel however, when the load increased from 3.6 kW to 10.8 kW, the HC values of ULSD, SOBS and SOB20 are increased by 28%, 26% and 6%, respectively. However, experimental results show that using biodiesel blends partly similar to ULSD operation in diesel engine according to cylinder gas pressure, heat release rate, heat release rate, knock density and AGT. (C) 2019 Elsevier Ltd. All rights reserved.
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    Performance enhancing and improvement studies in a 600 kW solar photovoltaic (PV) power plant; manual and natural cleaning, rainwater harvesting and the snow load removal on the PV arrays
    (Pergamon-Elsevier Science Ltd, 2022) Sevik, Seyfi; Aktas, Ahmet
    This study aims to analyze many efficiency-enhancing and improvement activities such as manual and natural cleaning, a PV power plant type rainwater harvesting system, thermal monitoring, and snow load removal in a 600 kW grid-connected photovoltaic (PV) power plant. The study shows that up to 5.66% power reduction can occur for PV modules that have been dirty for close to one year. It was determined that the dust removal effect of the rain was up to 0.94%. This study showed that the potential for collecting rainwater from a small part of the PV plant is approximately 118 m(3)/year and that the harvesting system will reach 1646 m(3)/year when applied to the whole plant. A snow load of 0.117 kN per m(2) was removed. On the basis of three days, 50-75% higher energy production was achieved compared to the other power plant with snow load. Snow removal on PV arrays both prevented PV degradation and resulted in increased power generation, while panel cleaning improved energy efficiency. This study an innovative approach with rainwater harvesting from solar power plants with large surface area for the use in panel cleaning and agriculture of the obtained water, which is a novel idea in increasing the efficiency of the power plants, combating climate change and drought. (C) 2021 Elsevier Ltd. All rights reserved.