Answer:
the entropy change of the fluid during the process process is is 1.337 kJ/K, the change for the source is -1.337 kJ/K and the total entropy change is 0
Explanation:
since the Carnot cycle is a reversible cycle, the entropy change is related with the heat exchanged through:
ΔS =∫dQ/T
since the temperature remains constant
ΔS =∫dQ/T=(1/T)*∫dQ = Q/T
Q= heat added to the system
T= absolute temperature = 400°C= 673 K
therefore
ΔS = Q/T = 900 kJ/ 673 K = 1.337 kJ/K
ΔS working fluid = 1.337 kJ/K
since the process is reversible, the entropy change of the universe (total entropy change) is 0 (there is no entropy generation). thus
ΔS universe = ΔS working fluid + ΔS source = 0
ΔS source= -ΔS working fluid = -1.337 kJ/K
