61 kjk 040 kjk the entropy generation in this case is

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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 Sgen 123 ∆Ssystem 123 Net entropy transfer by heat and mass Entropy generation Change in entropy Sgen ∆Ssystem Q out Tb or 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...
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This document was uploaded on 11/28/2012.

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