Full exam for Energy Conversion A in the Energy Engineering degree programme at Politecnico di Milano. The document covers: ENERGY CONVERSION Exam 11/07/2023 Please, write your person code and surname-name on all sheets you hand in. Exercise 1 (10 points) Consider an intercooled gas turbine characterized at 15 °C and 1 bar, named “base case”, by: • overall compression ratio, 𝛽𝑇𝑂𝑇: 42, •
Full exam for Energy Conversion A in the Energy Engineering degree programme at Politecnico di Milano. The document covers: ENERGY CONVERSION Exam 11/07/2023 Please, write your person code and surname-name on all sheets you hand in. Exercise 1 (10 points) Consider an intercooled gas turbine characterized at 15 °C and 1 bar, named “base case”, by: • overall compression ratio, 𝛽𝑇𝑂𝑇: 42, •
Import quality: text was extracted directly from the original document.
Representative passages recognised in different parts of the material. The full extracted text remains available to search, while this compact preview makes the page easier to read.
ENERGY CONVERSION Exam 11/07/2023 Please, write your person code and surname-name on all sheets you hand in. Exercise 1 (10 points) Consider an intercooled gas turbine characterized at 15 °C and 1 bar, named “base case”, by: • overall compression ratio, 𝛽𝑇𝑂𝑇: 42, • low-pressure compression ratio: 𝛽𝐿𝑃 = √𝛽𝑇𝑂𝑇 3 , • high-pressure compressor inlet temperature: 30 °C, • net electric power: 110 MW, • net electric specific work: 520 kJ/kg, • net electric efficiency: 45%; • all air bleedings are from the high-pressure compressor. Moreover, consider an off-design condition, named “better-intercooling case”, in which the high-pressure compressor inlet temperature is 20 °C, without modifying the equipment, in particular the turbomachinery . Neglecting pressure drops, please: i. clearly motivate the solution procedure and highlight the assumptions (1 point); ii. sketch the process flow diagram, the T-s diagram, and the T-Q diagram of the intercooler for the base case (2.0 point); iii. calculate the second-law efficiency loss due to intercooling in the base case (1.5 points); iv. determine the low-pressure compressor technical power in the base case and in the better-intercooling case (3 pts); v. indicate without computing how and why the high-pressure compressor technical power changes from the base case to the better-intercooling case (2.5 points). Exercise 2 (12 points) A liquefied natural gas regasification process is designed as follows. • Methane (critical temperature of -82.6 °C, critical pressure 4.6 MPa, ideal gas specific heat at constant pressure 2100 J/(kg K), and ideal liquid density 420 kg/m3) is stored at ambient pressure in saturated liquid conditions (-161 °C). It is pumped to 8 bar and, then, heated up to -60 °C through heat transfer in a CO2 condenser. The CO2…
First page of the document.
