Three power plants U, V and W operate between a high-temperature boiler at and a…

PHYSICS · Subjective · AP · Physics 2: Algebra-based · Thermodynamics · Thermodynamics

Problem

Three power plants U, V and W operate between a high-temperature boiler at

T_H = 800\,\text{K}

and a condenser at

T_C = 320\,\text{K}

. Their per-cycle heat and work data are: Plant U :

Q_H = 1000\,\text{kJ}

Q_C = 500\,\text{kJ}

Plant V :

Q_H = 1200\,\text{kJ}

Q_C = 540\,\text{kJ}

Plant W :

Q_H = 900\,\text{kJ}

Q_C = 360\,\text{kJ}

a) For each plant compute the thermal efficiency. b) For each plant determine the entropy change of the universe per cycle. c) Rank the three plants in order of thermodynamic desirability, taking into account both efficiency and entropy generation. d) Comment on whether any of the plants violates the Kelvin–Planck statement of the Second Law.

Related theory

Second Law & Entropy
Second Law of Thermodynamics
Heat Engines
Thermodynamics
Second law and Carnot cycle

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