Homework #1 Solutions
Fall 2010 - Solution
1. The zeroth law of thermodynamics states that two bodies are in thermal equilibrium if both have the same
temperature reading, even if they are not in contact.
2. A barometer is used to measure the height of a

M. Forms of Energy (Ch-2: sec. 2-2)
1. Energy exists in different forms (thermal, mechanical, kinetic, potential,
electric, chemical, nuclear).
2. Macroscopic forms of energy: related to motion and the influence
of some external effects such as gravity, m

CHAPTER 1
Basic Concepts of
Thermodynamics
1
Chapter 1
A. Thermodynamics and Energy.
B. Dimensions and Units.
C. Closed and Open Systems.
D. Properties of a System.
E. Density and Specific Gravity SG .
F. State and Equilibrium:
G. Process and Cycles.
H. T

CHAPTER 2
Energy, Energy
Transfer and General
Energy Analysis
1
A. Introduction: Forms of Energy:
1. Energy exists in different forms (thermal, mechanical, kinetic, potential,
electric, chemical, nuclear).
2. Macroscopic forms of energy: related to motion

Chapter 6
The Second Law
of
Thermodynamics
1
Chapter 6: The Second Law of Thermodynamics
A. Introduction.
B. Definitions.
C. Heat Engines (HE) Power Plant.
D. Refrigerators REF & Heat Pumps HP.
E. Reversible and Irreversible Processes.
F. Carnot Cycle.
2

Chapter 7
ENTROPY
2nd Law
A measure of waste
(lost work)
The 2nd Law restricts
the direction of
possible process
1
Chapter 7
ENTROPY S -2nd Law
Part 1: Closed System
A. Introduction:
B. Clausius Inequality (2nd Law for cyclic process).
C. Entropy S kJ/K

Chapter 5
Mass and Energy Analysis
of Control Volumes
(Open Systems)
1
Chapter 5: Mass and Energy Analysis of Control Volumes (Open
Systems)
A. Conservation of Mass Mass Balance (Continuity Equation).
for Open System CV.
B. Conservation of Energy Energy B

D. The Increase of Entropy Principle:
1. Recall : The 2nd Law for a Process:
S = S2 S1 = m( s2 s1)
2
1
kJ/k
For any adiabatic process: Sad 0
2. Consider the following isolated (Q= 0)
system :
a. The total entropy change Stotal of an
isolated system is t

CHAPTER 3
Properties of
Pure Substances
1
CHAPTER 3: Properties of Pure Substances
A. Pure Substance.
B. Phase-change Processes of Pure Substances.
C. Saturation Temperature and Saturation Pressure.
D. Property Diagram for Phase-Change Processes.
E. Inter

C. Closed and Open Systems:
1. Definitions:
a. System: region chosen for study.
b. Surroundings: region outside the system.
c. Boundary: A real or imaginary surface that separates the system from its
surroundings. (It could be FIXED OR MOVEABLE).
c. Two k

Example: P7-60: A 75-kg copper block initially at 110C is
dropped into an insulated tank that contains 160 L of water at
15C. Determine the final equilibrium temperature and the
total entropy change for this process.
Solution:
75 kg
160 L
1
2
H. Isentropi

Chapter 8
EXERGY
A measure
of work potential
EXERGY
A. Introduction.
B. Reversible Work .
C. Irreversibility I.
D. Exergy X (Availability): work potential of energy.
E. 2nd Law efficiency hII
F. Examples
2
A. Introduction:
1. 1st Law of Thermodynamics:
Q

1
ME 321 Thermodynamics
Homework #7
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3
4
1
5
6
7. Air in an ideal Diesel cycle is compressed from 3 L to 0.15 L, and then it expands during the
constant pressure heat addition process to 0.30 L. Under cold air standard conditions, the thermal
efficiency

Homework #3 Solutions
Fall 2010
1. A piston-cylinder device contains nitrogen gas at a specified state. The final
temperature and the boundary work are to be determined for the isentropic expansion of
nitrogen.
Properties The properties of nitrogen are R

ME 321 Thermodynamics
Homework #2
1
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3
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5
6
6
Fundamentals of Engineering Exam Problems
7. A rigid tank contains 6 kg of an ideal gas at 3 atm and 40C. Now a valve is opened, and half of
mass of the gas is allowed to escape. If the final pressure in the

Homework #4 Solutions
Fall 2010
1.
2.
3.
4.
5.
6. An adiabatic heat exchanger is used to heat cold water at 15C entering at a rate of 5 kg/s by hot air at 90C
entering also at rate of 5 kg/s. If the exit temperature of hot air is 20C, the exit temperature

Homework #6 Solutions
Fall 2010
Qin
1. Heat addition, entropy increases.
2. Heat rejection, entropy decreases.
Qout
3
1
4
1
5
1
6
1
7. Air is compressed steadily and adiabatically from 17C and 90 kPa to 200C and 400 kPa. Assuming constant
specific heats f

Homework #5 Solutions
Fall 2010
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6
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7. The drinking water needs of an office are met by cooling tab water in a refrigerated water fountain from 23C to
6C at an average rate of 10 kg/h. If the COP of this refrigerator is 3.1, the requ

1
ME 321 Thermodynamics
Homework #5
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3
4
1
5
1
6
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7. The drinking water needs of an office are met by cooling tab water in a refrigerated water fountain from 23C to
6C at an average rate of 10 kg/h. If the COP of this refrigerator is 3.1, the required p

1
ME 321 Thermodynamics
Homework #6
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3
4
1
5
1
6
7. Air is compressed steadily and adiabatically from 17C and 90 kPa to 200C and 400 kPa. Assuming constant
specific heats for air at room temperature, the isentropic efficiency of the compressor is
(a) 0.7

1
ME 321 Thermodynamics
Homework #4
2
3
4
1
5
1
6. An adiabatic heat exchanger is used to heat cold water at 15C entering at a rate of 5 kg/s by hot air at
90C entering also at rate of 5 kg/s. If the exit temperature of hot air is 20C, the exit temperatur

1
ME 321
Thermodynamics
Homework #7 Solution
2
3
4
1
5
1
6
1
7. Air in an ideal Diesel cycle is compressed from 3 L to 0.15 L, and then it expands during the
constant pressure heat addition process to 0.30 L. Under cold air standard conditions, the therma

Part 2
2nd Law Analysis for Open System CV
A. The Increase of Entropy Principle for Open System .
B. Reversible steady-flow work .
C. Multistage Compression with Intercooling.
D. h-s diagram (Mollier diagram).
H. Isentropic Efficiencies of Steady-Flow Dev