a)
The final mass
a)

Answer to Problem 75P
The final temperature of the helium is
Explanation of Solution
Write the expression for the final mass
Here, volume of the rigid tank is
Conclusion:
Refer to Table A-12, “Saturated refrigerant-134a-Pressure table”, obtain the following properties at the pressure of
Here, internal energy of saturated liquid and saturated vapor is
Refer to Table A-12, “Saturated refrigerant-134a-Pressure table”, obtain the following properties at the pressure of
Here, enthalpy of saturated liquid is
Refer to Table A-12, “Saturated refrigerant-134a-Pressure table”, obtain the following properties at the pressure of
Substitute
Thus, the final mass
b)
The reversible work
b)

Answer to Problem 75P
The reversible work
Explanation of Solution
Write the expression for the mass balance for the control volume system.
Here, mass of the refrigerant at the inlet is
Write the expression for the energy balance for the system.
Here, net energy transfer in to the control volume is
Write the expression for the initial mass
Here, mass of the liquid refrigerant is
Write the expression for the initial internal energy
Write the expression for the initial entropy
Write the expression for the entropy balance for refrigerant.
Here, entropy generation is
Write the expression for the reversible work
Here, exergy destroyed is
Since, the process does not involve any actual work, substitute 0 for
Here, dead state temperature is
Conclusion:
Substitute
Substitute
Substitute
Substitute
Substitute
Substitute
Substitute
Thus, the reversible work
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Chapter 8 Solutions
THERMODYNAMICS(SI UNITS,INTL.ED)EBOOK>I
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