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    Energy analysis of concentrated photovoltaic/thermal panels with nanofluids
    (International Journal of Thermodynamics, 2021) Dumrul, H.; Yilmaz, S.; Kaya, M.; Ceylan, I.
    In this study, a prototype system was established for location heating application and electricity generation through utilizing two concentrated photovoltaic thermal panels (CPV/T) possessing flat surface receivers connected in series with each other. The purpose of the system is to supply the heating needs of a room in winter season and to meet the electricity requirement of the equipment used in this system. In the analysis of the installed system, different refrigerants (10% mono propylene glycol + 90% water and 0.5% Al2O3-water nanofluid) were tested at three different flow rates (0.4 m3/h, 0.5 m3/h, 0.6 m3/h). Throughout the experiments, the fan-coil air outlet temperature used to heat the room was adjusted to 35 °C with an inverter and a process control device. The results attained from the experiments carried out using different fluids throughout different months and days (April-May) have demonstrated that the thermal and electrical efficiencies of the system are found to be in good agreement with each other when evaluated in terms of the fluids utilized. The highest electrical energy recovery was found as 268 W at 0.6 m3/h flow rate for propylene glycol-water mixture and 194 W at 0.5 m3/h flow rate for nanomixture. The total thermal energy efficiency for the system using different fluids was found to be around 22%. The total thermal energy gain of the system was also calculated as 2312 W at 0.6 m3/h for the propylene glycol mixture and 2041 W at 0.5 m3/h for the nanomixture. © 2021 International Journal of Thermodynamics. All rights reserved.
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    An Experimental Study of the Effects of Heat-Sink Surface Form on PV Module Cooling and Electrical Performance
    (American Society of Civil Engineers (ASCE), 2023) Ekiz, A.; Selimli, S.; Dumrul, H.
    In this study, the effect of the fin surface on the electrical performance of passively cooled photovoltaics (PV) modules equipped with flat (PVf) and tread (PVt) surface finned heat sinks was experimentally investigated. PVf and PVt modules were fabricated with heat sinks by filling phase change material (paraffin)/aluminum chip mixture between the PV module and heat sink. The mean ambient temperature, solar radiation, and solar power during the experiment were about 13°C, 864 W/m2, and 247, respectively. The electrical power of the PVf and PVt modules was increased by 10.84% and 17.2%, respectively, while the average temperature was decreased by 11.78% and 16.5%, respectively, compared to the PV module. The PVt module provided 5.37% more effective cooling and a 5.74% higher electrical power than the PVf module. The electrical efficiency of the PV module was 11.35%, and the rate of increase was 1.21% and 1.95% for the PVf and PVt modules via cooling. Compared to the PV module, the electrical exergy of the PVf and PVt modules increased by 10.84% and 17.2%, respectively, at an average solar exergy of 230.61 W, while their thermal exergy decreased by 23.64% and 32.3%, respectively. Compared to the PVf module, the thermal exergy of the PVt module was reduced by 11.34%, and the electrical exergy was increased by 5.74%. The increase in exergy efficiency is 3.14% and 4.51% for PVf and PVt modules versus the PV module. © 2022 American Society of Civil Engineers.