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POWER PRODUCTION FROM RENEWABLE ENERGY AY 2015-16 3rd March 2016 Prof. Silva and Manzolini Time: 1,5 hours Instructions for the examination: 1) Clearly indicate your name on all the sheets you will deliver. 2) The score refers to exercises done in a comprehensive manner with exact numerical results. Numerical results correct but not accompa- nied by explanations will not be taken into account. The final score will be normalized according to the average results. 3) Answer briefly and clearly only to the asked questions. Calculations and explanations which do not respond to the questions will not be considered for evaluation even if correct. 4) Talking with colleagues and / or cheating will cause the cancellation of the exam. 5) All the needed data for the resolution of exercises lies on this paper. It’s NOT ALLOWED to use material other than this (e.g. books, clip- board etc.) Exercise 1 (17 points) The performances of a geothermal plant based on vapour -dominated reservoir , direct -steam, single -flash should be assessed. The geothermal fluid composition on mass base is 95% H20 and the remaining is N2. Temperature of the geothe r- mal fluid 200°C Turbine isentropic efficiency 88% Pressure of the geothermal fluid 15.5 bar Steam turbine generator efficie n- cy 97.5% Mass flowrate of the ge o- thermal fluid 100 kg/s Condensing pressure 0.1 bar Enthalpy of the water 2600 kJ/kg Auxiliaries for heat rejection 20 kWel/MWth Non-condensable gas co m- pressor isentropic efficiency 85% Non-condensable gas compre s- sor driver efficiency 95% Design the lay-out of the plant with all the components (2 points). Calculate the net power output of the geothermal plant (whenever nec essary assume reasonable numbers and evaluate only one flash pressure justifying its selection) (6…