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Politecnico di Milano School of Industrial Engineering Course Energy Systems proff. S. Consonni, E. Martelli, M. Romano - Academic Year 2020-21 Energy Systems LM – written test of 19 January 2021 page 1 of 3 Written Exam of 19 January 2021 - Problems - Time: 2 hours PLEASE NOTICE 1) Exam is open book, but computers and cell phones are NOT allowed. Talking with colleagues and/or copying will lead to the immediate cancellation of the exam. 2) Answer clearly ONLY to the questions posed by the problem se ts. Even if correct, additional considerations and/or calculations will NOT be considered. 3) Fill this sheet with your name and return it together with your solutions. 4) Mark each sheet of the solution with your name and page number. 5) In addition to the points obtained for the solution of each problem, a bonus of max 3 points may be given based on whether the solution of each problem is complete, with clear details and explanations. Problem data depend on your person code according to the following two variables: X = sum of the numbers of your person code Y = sum of the first 4 numbers * sum of the last 4 numbers of your person code So, for instance, if the person code is 12345678  X = 36  Y = 10*26 = 260 INDICATE ON THE FIRST PAGE THE VALUES OF X AND Y DERIVING FROM YOUR PERSON CODE THAT YOU WILL USE IN THE EXAM Problem 1 (16 points, including Q1) The system represented in Fig. 1 generates a useful thermal power 𝑸ሶ𝒖 ൌ𝟐∗𝒀 kWth. Fig. 1: Boiler with air pre-heater Combustion air (flow 1) and fuel (flow f) are both at 1 atm, 25°C. Fully oxidized combustion products are discharged to ambient at 3*X°C (flow 5) The molar composition of air is (1/4.76 = 21.008%) O2, (3.76/4.76 = 78.992%) N2 The molar composition of combustion products is:  3/25.8 = 11.628% CO2  4/25.8 =…