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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 2018-19 Energy Systems – Theoretical Questions – 9 September 2019 page 1 Written Exam 9 September 2019 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 (18 points) Consider a vapor compression reversed cycle. A) Write the expression of the COP for a refrigeration cycle and for a heat pump cycle, for the ideal Carnot reversed cycle. Discuss the effect of evaporation and condensation temperatures on the COP B) Write the expression of the COP for a refrigeration and for a heat pump cycle, for a real cycle using a real fluid. For given condensation and evaporation temperatures, given subcooling ΔT and given compressor inlet temperature,…