Concept explainers
(a)
The entropy change of the computer chips.
(a)
Answer to Problem 61P
The entropy change of the computer chips is
Explanation of Solution
Write the expression for the energy balance equation.
Here, the total energy entering the system is
Substitute
Here, the mass is
Determine the heat released by the computer chips.
Here, the mass of the computer chips is
Determine the mass of the refrigerant vaporized during this heat exchange process.
Here, the saturated specific enthalpy change upon vaporization at
Determine the change in the entropy of the R-134a.
Here, the mass of the refrigerant vaporized at state 2 is
Determine the entropy change of the computer chips.
Determine the total entropy change of the entire system.
Conclusion:
Substitute 10 g for
From the Table A-11, to obtain the value of the specific enthalpy change upon vaporization, entropy of the refrigerant vaporized at state 2, entropy of the refrigerant liquid at state 2, entropy of the refrigerant liquid at state 1 at final temperature of
Substitute
Substitute
Thus, the entropy change of the computer chips is
Substitute 10 g for
Thus, the entropy change of the R-134 is
Substitute
Thus, the entropy change of the entire system is
(b)
The entropy change of the R-134.
(b)
Answer to Problem 61P
The entropy change of the R-134 is
Explanation of Solution
Determine the entropy change of the computer chips.
Conclusion:
Substitute 10 g for
Thus, the entropy change of the R-134 is
(c)
The entropy change of the entire system.
(c)
Answer to Problem 61P
The entropy change of the entire system is
Explanation of Solution
Determine the total entropy change of the entire system.
Conclusion:
Substitute
Thus, the entropy change of the entire system is
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Chapter 7 Solutions
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