Ex 2 GEOTHERMAL BINARY POWER PLANT Results

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BINARY GEOTHERMAL CYCLE Power Production from Renewable Energy – A.Y. 2020/21 Prof. Paolo Silva – Ing. Dario Alfani Pay attention: the results may slightly differ due to the accuracy of the optimization process (obtained through the parametric approach) and due to the tolerance applied to the solution of the energy balances at the evaporator. These results are obtained with a preliminary optimization step of 0.5 bar (of the evaporation pressure) and a final optimization step of 0.05 bar just in proximity of the optimal point. With this approach the optimal evaporation pressure obtained is equal to 8.05 bar, confirming the correctness of the optimal evaporation pressure obtained with the Excel add-in solver optimization tool which is equal to 8.048 bar. Results 1) Cycle with one pressure level – simple cycle Optimal evaporation pressure 8.05 bar Temperature TB 129.48 °C Mass flow rate isopentane 169.16 kg/s Net electric power 8.41 MWel η I (η cycle) 11.14 % η thermal recovery 64.90 % η plant 7.23 % η II (assumed T0=18°C) 28.31 % Mass flow rate cooling water 1967.75 kg/s Area economizer 764.86 m2 Area condenser 14723.03 m2 T [°C] p [bar] h [kJ/kg] s [kJ/kgK] x [-] ρ [kg/m3] 1 30.00 1.12 -321.89 -1.070 0.00 642.05 2 30.65 10.06 -319.90 -1.068 0.00 643.34 3 103.12 8.05 -152.37 -0.575 0.00 539.47 4l 106.12 8.05 -144.35 -0.554 0.00 533.60 4 106.12 8.05 126.18 0.159 1.00 22.58 5is 57.67 1.12 53.02 0.159 1.00 3.05 5 65.63 1.12 67.65 0.203 1.00 2.97 5v 30.00 1.12 4.47 0.006 1.00 3.36 0 20 40 60 80 100 120 140 160 180 0 10000 20000 30000 40000 50000 60000 70000 80000 Temperature [°C] Heat exchanged [kW] PHE TQ diagram T,geo T,wf 0 10 20 30 40 50 60 70 0 10000 20000 30000 40000 50000 60000 70000 Temperature [°C] Heat exchanged [kW] Cond TQ diagram T,wf T,cw Results 2) Cycle with…