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- 저자 : Yavuz Köysal (검색결과 4 건)
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Performance Analysis on Solar Concentrating Thermoelectric Generator Coupled with Heat Sink
Yavuz Köysal 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.2
The usage of thermoelectric generators (TEGs) is rapidly increasing where the waste heat exists. Today, many experiments are being conducted to investigate solar energy systems with waste heat. This work focuses on the performance of an individual TEG via a spot Fresnel lens. Therefore, an experimental system was constructed so that the TEG module could show high performance under the concentrated solar radiation. For this aim, the system was adapted to one-axis sun tracking system for receiving maximum solar irradiation. It was observed that the obtained experimental values of the parameters such as open circuit voltage, hot side temperature and cold side temperature of the TEG module are consistent with the collected solar values. The experimental data was collected at GPS coordinates of 41°14′N and 36°26′E (Samsun, Turkey) on 8th of September, 2017. The maximum open circuit voltage value was obtained as 0.822 V.
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Tahsin Atalay,Yavuz Köysal,Ali Ekber Özdemir,Engin Özbaş 한국정밀공학회 2018 International Journal of Precision Engineering and Vol.5 No.1
This paper investigates the effects of heat pipes filled with water and nanoparticles (MgO) on electricity generation. The experimental setup comprises of two-phase thermo-syphon heat pipes filled with water or MgO nanoparticle-water suspension, thermoelectric generator (TEG) modules and heat sinks that use passive and active cooling systems. Concentrated solar radiation with heat pipes was used as a heat source for heating. Specially constructed heat sinks with coolant tunnels were used for cooling. Heating and cooling processes are needed to create a temperature difference to generate electrical energy. The constructed model represents the influence of basic parameters such as the tilt angle of heat pipes, working fluids, cooling process, etc. on the maximum power generated. Systems in the constructed setup were arranged with a specific angle to the incident angle of solar radiation. The experiment was carried out on August 5th, 2015, in the northern coast of Turkey, city of Samsun with latitude of 41o14’ N. The results obtained show that the presented experimental setup can be used to evaluate thermoelectric energy potential of local areas or to investigate optimum cooling or heating processes.
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Hasan Tanak,Yavuz Köysal,Şamil Işık,Hanifi Yaman,Vefa Ahsen 대한화학회 2011 Bulletin of the Korean Chemical Society Vol.32 No.2
The compound 3-(2-Mercaptopyridine)phthalonitrile has been synthesized and characterized by IR, UV-vis, and X-ray single-crystal determination. The molecular geometry from X-ray determination of the title compound in the ground state has been compared using the Hartree-Fock (HF) and density functional theory (DFT) with the 6-31G(d) basis set. The calculated results show that the DFT and HF can well reproduce the structure of the title compound. The energetic behavior of the title compound in solvent media was examined using the B3LYP method with the 6-31G(d) basis set by applying the Onsager and polarizable continuum model. Using the TD-DFT and TD-HF methods, electronic absorption spectra of the title compound have been predicted and good agreement with the TD-DFT method and the experimental determination was found. The predicted nonlinear optical properties of the title compound are much greater than those of urea. Besides, molecular electrostatic potential of the title compound were investigated by theoretical calculations. The thermodynamic properties of the compound at different temperatures have been calculated and corres ponding relations between the properties and temperature have also been obtained.
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Tahsin Atalay,Yusuf Yakut,Yavuz Köysal,Seyda Özbektaş,Hakan Bülbül,Bahattin Topaloğlu 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.9 No.2
In this study, it is aimed to determine the energy generation capability of the designed and manufactured thermoelectric system when mounted on the two-axis solar tracking system. Thus, it was possible to compare the results obtained from current study with previous study. The system used in previous study was comprised of a thermoelectric generator (TEG) for energy conversion, a linear Fresnel lens for concentrating solar rays, and a one-axis tracking system to increase the electrical and thermal efficiency of the system. In this study, a dual-axis (two-axis) tracking system was used as a tracking system to examine the change in thermal and electrical efficiency. Therefore, experimental measurements were performed again using both two-axis and one-axis solar tracking systems on 16th October 2019 and 17th October 2019, respectively, at the location which falls at 41°14′ N and 36°26′ E. Additionally, the heat transfer and electricity generation performance of TEG was theoretically analyzed using CFD model. For this purpose, a numerical model consisting TEG with heat sink was developed. It was observed that the model data obtained and the experimental data were in good agreement. The values of parameters such as temperature, solar radiation, wind speed and TEG open circuit voltage were measured instantaneously during the measurements. The maximum open circuit voltages obtained is 1.02 and 1.13 V for one-axis and dual-axis systems, respectively. The solar radiation values were measured as 464 and 472 W∕m2 , respectively when the maximum open circuit voltages value is obtained. The duration for measurements was kept about 15 min so that the average values of these parameters were used in calculations. Thus, the values of maximum output power ( P maxout) , electrical efficiency (ηe) and Seebeck coefficient ( TEG) were calculated and given in the paper.
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