Concept explainers
a)
The temperature of the saturated steam
a)
Answer to Problem 85P
The temperature of the saturated steam
Explanation of Solution
Write expression for the mass balance on the chamber.
Here, mass rate of liquid water at state 1 is
Conclusion:
Refer to Table A-4, “Saturated water-temperature table”, obtain the following properties at the temperature of
Here, enthalpy of saturated liquid is
Refer to Table A-4, “Saturated water-temperature table”, obtain the following properties at the temperature of
Substitute
Refer to Table A-4, “saturated water–temperature table”, for the enthalpy of
Enthalpy |
Temperature, |
2713.1 | 125 |
2719 | ? |
2720.1 | 130 |
Here, temperature of the saturated steam at state 2 is
Substitute
Thus, the temperature of the saturated steam
b)
The exergy destruction
b)
Answer to Problem 85P
The exergy destruction
Explanation of Solution
Calculate the specific exergy of state 2
Here, dead state temperature is
Calculate the specific exergy of state 3
Calculate the specific exergy of state 1
Calculate the exergy destruction
Conclusion:
Refer to Table A-4, “saturated water–temperature table”, for the enthalpy of
Temperature, |
Entropy |
125 | 7.0771 |
129.2 | ? |
130 | 7.0265 |
Substitute
Substitute
Substitute
Substitute
Substitute
Thus, the exergy destruction
c)
The second law efficiency
c)
Answer to Problem 85P
The second law efficiency
Explanation of Solution
Write the expression for the second law efficiency
Here, rate of exergy recovered is
Conclusion:
Substitute
Thus, the second law efficiency
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Chapter 8 Solutions
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