1- Air is compressed to 11 bar and 650 K conditions by a compressor. Then, this fluid is defined as cold fluid and enters a counter-flow heat exchanger in compressed condition at 10.6 bar and 900 K conditions. Exhaust gases, defined as hot fluids, are transported to the same heat exchanger from the exit of a turbine at 1,2 bar and 1000 K conditions, and then they leave the heat exchanger at 1 bar pressure. The volumetric flow of the cold fluid is 75 m3 / s and the mass flow of the hot fluid is 100 kg / s. The heat loss from the heat exchanger, whose outer surface temperature is 40 oC, to the environment at 25oC is 0.5 MW. The system operates under continuous regime conditions and it will be assumed that the specific heating temperatures of the fluids change with temperature. The average density value of the cold fluid is 1.2 kg / m3.
a- Write the 1st Law of Thermodynamics by making the necessary acceptances for the given question.
b- Find the exit temperature of the hot fluid from the heat exchanger.
c- Find the net exergy change between the inlet and outlet of the hot fluid.
d- Find the net exergy change between the cold fluid inlet and outlet.
e- Write the entropy balance or exergy balance by making the necessary acceptances for the given question.
f- Find the exergy breakdown.
g- Find the entropy generation.