Unformatted text preview: xtended system is at the surrounding temperature of 25°C. The entropy balance for this extended system (system
immediate surroundings) yields Sin Sout
123 Net entropy transfer
by heat and mass Entropy
in entropy Sgen ∆Ssystem Q out
Sgen Q out
Tb ∆Ssystem (25 600 kJ
273) K (–1.61 kJ/K) 0.40 kJ/K The entropy generation in this case is entirely due to irreversible heat transfer
through a finite temperature difference.
Note that the entropy change of this extended system is equivalent to the entropy change of water since the piston-cylinder device and the immediate surroundings do not experience any change of state at any point, and thus any
change in any property, including entropy.
Discussion For the sake of argument, consider the reverse process (i.e., the
transfer of 600 kJ of heat from the surrounding air at 25°C to saturated water
at 100°C) and see if the increase of entropy principle can detect the impossibility of this process. This time, heat transfer will be to the water (heat gain instead of he...
View Full Document