ES 28 08 2024 theoretical test

Page 1

POWER PRODUCTION FROM RENEWABLE ENERGY AY 2023-24 28th August 2024 Prof. Andrea Giostri Time: 1 hour NAME and SURNAME:.................................................................................................................................................. COURSE and CFU:............................................TYPE (Complete or Theory only :................................................. Optional Teamwork grade:..............................Previous Practical text grade( if Theory only) : ........................... Instructions for the examination: 1) Clearly indicate your name on all the sheets you will deliver. 2) Give a synthetic and clear answer to as many questions as possible. The final score will be normalized according to the average results. 3) Talk with colleagues and / or cheating will cause the cancellation of the exam. OPEN QUESTIONS (points 18) 1. For All Students Consider CSP technology : Define the thermal and optical efficiency of a parabolic trough collector and describe each loss contribution from solar to thermal energy conversion. For a given collector tube size discuss how the concentration ratio would impact on the different loss mechanisms. 2b. For Management engineering (5 CFU): Discuss and explain the reason why the blades of a multi-MW modern wind turbine are twisted. Draw the velocity triangles at the tip and at the hub of a representative blade. 2c. For Energy, Mechanical and Management Engineering students (8 CFU): Discuss a power plant fuelled by biomass for electricity generation and examine the challenges that limit the achievement of high energy conversion efficiencies. MULTIPLE-CHOICE QUESTIONS (points 12) Answer to the following 15 questions. Select the box with correct answer (0.8 points if correct, -0.3 points if…