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Politecnico di Milano Department of Energy - School of Industrial Engineering Course Energy Systems proff. S. Consonni, E. Martelli, M. Romano - Academic Year 2019-20 Energy Systems – Theoretical Questions – 24 June 2021 page 1 Written Exam 24 June 2021 Theoretical Questions ‐ Time: 1.00 h PLEASE NOTICE 1) Books, lecture notes, cell phones are strictly forbidden. Using them or talking with colleagues and/or copying will lead to the immediate invalidation of the exam. 2) Answer clearly ONLY to the questions. Even if correct, additional considerations will NOT contribute to the final grade – and you have NOT enough time! 3) Fill this sheet with your name and return it with your answers. 4) MARK EACH SHEET OF YOUR ANSWERS with YOUR NAME AND PAGE/SHEET NUMBER. 5) WRITING AND SHEET/PAGE SEQUENCE MUST BE LEFT TO RIGHT AS USED IN WESTERN COUNTRIES. 6) The final grade is the sum of the points assigned to the answer of each question plus a bonus of max 3 points. The bonus will be given based on completeness, clarity and details of the explanations. 7) Wherever possible, support your statements with clear drawings and/or graphical representation 8) ORGANIZE YOUR ANSWERS CLEARLY: ANSWER TO 1.a; ANSWER TO 1.b, ETC. FIRST NAME…………………………………….......……FAMILY NAME………………………………………………….. Question 1 (16 points) Consider two combined cycles, featuring a heat recovery steam cycle: ‐ with one pressure level ‐ with two pressure levels without reheat You are requested to: A) Draw the HRSG of the two plants, showing the position of econom izer, evaporator and superheater. B) Draw the T‐Q diagrams of the two HRSGs. C) Write the equations of: (i) the net electric efficiency of the combined cycle, (ii) the net electric efficiency of the gas turbine, (iii) the heat recovery efficiency of the HRSG,…