Browsing by Author "Sirin C."

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    NUMERICAL AND EXPERIMENTAL INVESTIGATION OF A DOUBLE-PIPE HEAT EXCHANGER WITH SiO2NANO-ADDITIVES
    (Begell House Inc., 2022) Selimefendigil F.; Sirin C.; Öztop H.F.
    In this work, numerical and experimental analyses of a double-pipe heat exchanger with SiO2 nanoparticles were performed. The numerical study was conducted by using the k-e turbulence model with the Galerkin weighted residual finite element method. The nanofluid was used in the inner pipe at various solid particle volume fractions. Effects of flow rate and temperature on the overall heat transfer coefficient were examined. The Brownian motion effect was included in the effective thermal conductivity of the nanofluid. It was observed that the overall heat transfer coefficient enhanced with the inclusion of nanoparticle and increasing the volumetric flow rate of nanofluid. Even though the validation of the experimental study was conducted, there are discrepancies between the numerical and experimental studies which become higher for a higher mass flow rate. The deviations are 4.60% and 27.50% at volumetric flow rates of 0.87 L/min and 2.15 L/min. © 2022 by Begell House, Inc.
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    Enhancing the performance of a greenhouse drying system by using triple-flow solar air collector with nano-enhanced absorber coating
    (Elsevier Ltd, 2022) Selimefendigil F.; Sirin C.; Ghachem K.; Kolsi L.; Alqahtani T.; Algarni S.
    In this research, the impacts of utilizing nano-embedded absorber coating in an auxiliary heater of a greenhouse drying system on the thermal and drying performances have been surveyed empirically. In this context, triple-flow solar air collectors with and without CuO nano-enhanced absorber coating have been designed and manufactured. Designed collectors then integrated to even-span greenhouse dryers to be used as an auxiliary heating device. In the experiments, greenhouse dryers have been tested with and without auxiliary heaters at constant flow rate which is 0.014 kg s-1. According to the experimental findings, utilizing triple-flow solar air heating device with and without nano-embedded paint decreased the drying time as 35.71% and 26.66%, respectively. Thermal and exergetic efficiencies for newly developed collectors were found between the range of 70.39-75.11% and 9.05-10.18%, respectively. In addition, specific energy consumption values were decreased by using collectors with and without nano-enhanced modification from 2.51 to 2.11 and from 2.61 to 2.18 kWh/kg, respectively. Attained outcomes of this study showed the successful utilization of nano-enhanced absorber coating in the auxiliary heating system of the greenhouse dryer. © 2022 The Authors.