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Öğe Energy and Exergy Analysis of Combined Organic Rankine Cycle-Single and Dual Evaporator Vapor Compression Refrigeration Cycle(Mdpi, 2019) Pektezel, Oguzhan; Acar, Halil IbrahimThis paper presents energy and exergy analysis of two vapor compression refrigeration cycles powered by organic Rankine cycle. Refrigeration cycle of combined system was designed with single and dual evaporators. R134a, R1234ze(E), R227ea, and R600a fluids were used as working fluids in combined systems. Influences of different parameters such as evaporator, condenser, boiler temperatures, and turbine and compressor isentropic efficiencies on COPsys and eta(ex,sys) were analyzed. Second law efficiency, degree of thermodynamic perfection, exergy destruction rate, and exergy destruction ratio were detected for each component in systems. R600a was determined as the most efficient working fluid for proposed systems. Both COPsys and eta(ex,sys) of combined ORC-single evaporator VCR cycle was detected to be higher than the system with dual evaporator.Öğe Energy and exergy analysis of erciyes university No. 1 heat center(Elsevier, 2024) Polat, Busenur; Acar, Halil Ibrahim; Kahraman, NafizThe present study comprises an energy and exergy analysis of a steam boiler with a capacity of 10 tons of steam per hour, 9817 m of pipelines of various diameters, and 96 heat exchangers in the heat exchanger centers under the usage unit (hospitals, academic institutions, and residences located) in Erciyes University Heat Center, which is still in use in Kayseri. Each element's exergy loss was calculated. These findings led to the discovery of exergy yields (second law yields). The outcomes are presented graphically. The analysis revealed that the steam boiler was the component with the most significant exergy loss, amounting to 5151.12 kW. The thermal efficiency of the boiler was calculated to be 93.1 %, while the exergy efficiency was determined to be 28.6 %. Following the boiler, the line losses in the pipelines were calculated to be 3.14 %. The second law efficiency of the Heat Center was found to be 22.7 %.Öğe Estimation of wind power potential in sivas cumhuriyet university campus using various probability density functions(Springer Heidelberg, 2025) Duman, Netice; Acar, Halil Ibrahim; Erturk, LutufWith the increase in energy consumption, resources are decreasing while costs are rising. The Covid-19 pandemic and wars in some countries have also led to increased costs. Considering the environmental damage, the search for new energy sources and the demand for existing renewable energy sources have increased. Among renewable energy sources, wind energy is one of the most prominent energy sources due to its environmental friendliness. In recent years, studies on wind characteristics and wind energy distribution have been conducted in many parts of the world. But, it has not been conducted that a detailed study using different probability density functions specifically for Sivas province in T & uuml;rkiye. This study investigated the wind energy potential for Sivas province using various probability density functions. Data from two nearby stations were used in the calculations. Despite the proximity of the stations, it was determined that the emerging wind trends showed some differences. For Station A, it is observed that probability density functions other than Rayleigh provide a better fit, especially at low wind speeds. However, deviations from actual values are observed at certain wind speeds. For Station B, functions other than Weibull show a better fit, although it can be said that the wind characteristics are more irregular in the winter season, and the predicted functions do not provide a better fit. Stations A and B exhibited different wind characteristics, except for the autumn season. It was observed that collecting data and analyzing wind power at the site where a wind farm will be established is quite important. As a result of the study, it was concluded that the potential wind powers at both stations were quite low and not very suitable for wind farm installation.Öğe Exergy analysis of a coal-fired thermal power plant in Kangal District of Turkey(Inderscience Enterprises Ltd, 2022) Erzen, Sevgi; Acar, Halil Ibrahim; Pektezel, OguzhanIn this study, thermodynamic analysis of Kangal thermal power plant operating in Turkey was performed. Energy and exergy values of 35 points in the power plant were calculated. Energy and exergy equations of all components were derived to analyse the system performance. Exergy destruction, the second law efficiency and the efficiency defect were calculated for the system components. Also, the effect of ambient temperature on exergetic performance of the turbines and the condenser was analysed. Results were presented in graphs. The boiler was determined as the equipment that caused the greatest exergy destruction with 91.7%. The second high pressure feed water heater showed the greatest second law efficiency with 94.39. Thermal and the second law efficiency of the power plant were found to be 32.8% and 52.6%, respectively. It was found that increase in ambient temperature had a positive effect on condenser while had a negative effect on turbines.Öğe EXERGY ANALYSIS OF A GROUND SOURCE HEAT PUMP SYSTEM FOR COLD CLIMATIC CONDITION OF SIVAS, TURKEY(Univ Zagreb Fac Mechanical Engineering & Naval Architecture, 2021) Duman, Netice; Buyruk, Ertan; Acar, Halil Ibrahim; Caner, Mustafa; Kilinc, Ferhat; Can, AhmetIn the present study, exergy analysis of a ground source heat pump (GSHP) is performed. For this purpose, a horizontal type GSHP test system is installed at Sivas Cumhuriyet University in Sivas Province. GSHP system consists of three main circuits. These are the ground heat exchanger (GHE), the heat pump (HP) and the heating circuit. The temperatures and pressures are measured at the various points of the system. Besides, the mass flow rate of the working fluid circulating in the GHE, heat pump and heat circuit are measured. In addition, power consumption of the compressor and the pumps are measured. Measured data were recorded every minute. The test data used in the calculations are related to the coldest day, December 18, 2016. Exergy loss, exergy efficiency, exergy loss ratio and thermodynamic perfect degree for each element of the system are computed. Exergy efficiency and thermodynamic perfect degree of the system are calculated as 0.27 and 0.86 respectively.
