Performance analysis of the Germencik geotermal power plant

The objective of this study is to calculate the efficiency of exegry in Germencik Geothermal Power Plant, which has a capacity of 47.4 MWe. As being the largest one in Turkey, this plant is operated by double flash system which is based on the method of analysis of energy and exergy to evaluate its performance. The exergy analysis has been applied to the whole plant considering the first and the second law of thermodynamics for each equipment. In this study, by using the actual data values the losses of exergy have been determined and the flow diagram of exegry has been illustrated. When making calculations, we have accepted dead state temperature as 18oC, and dead state pressure as 1.012 bars.The plant has 7 production and 6 reinjection wells. From these production wells, geothermal fluid reaches the plant at an average temperature ranging from 194 oC to 214 oC, pressure of 23 bars to 30 bars and a total flow rate of 688.8 kg/s. An exergy input of 134167 kW is obtained from these wells. The largest exergy input of 36406 kW is obtained from OB-14 and this accounts for 27.1% of total exergy input. Moreover, major exergy losses and their exergy input account for 3.34%(4475 kW) for valves, 22.81%(30609 kW) for high and low pressure separation process during the decomposition of geothermal fluid, 5.1%(6836 kW) for turbine-generator during the conversion of steam into mechanic work, 9.42%(12644 kW) for cooling tower, 5.53%(7414 kW) for internal use, and finally 22.7%(30452 kW) for reinejection wells. Additionally, the second law efficency of turbine-generator has been found to be 87.4% and the second law efficiency of overall plant has been found to be 35.33%.The obtained results have been given in tables and the largest loss of exergy has been determined to occur in seperators.