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Unformatted text preview: 1 MAE 301: Engineering Thermodynamics Spring 2010 HOMEWORK #7 ( Solutions ) Problem 1. Problem 6.14C from the book. Answer: (a) No, (b) Yes. According to the second law, no heat engine can have and efficiency of 100%. Problem 2. Problem 6.17 from the book. Solution: The rate of heat supply to the power plant is determined from the thermal efficiency relation, MW 1500 0.4 MW 600 th out net, = = = η W Q H & & The rate of heat transfer to the river water is determined from the first law relation for a heat engine, MW 900 = − = − = 600 1500 out net, W Q Q H L & & & In reality the amount of heat rejected to the river will be lower since part of the heat will be lost to the surrounding air from the working fluid as it passes through the pipes and other components. Problem 3. Problem 6.24E from the book. Solution: The rate of solar energy collection or the rate of heat supply to the power plant is determined from the thermal efficiency relation to be Btu/h 10 2.986 7 × = ⎟ ⎟ ⎠ ⎞...
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This note was uploaded on 05/19/2010 for the course MAE 301 taught by Professor Hassan during the Spring '08 term at N.C. State.
- Spring '08