Ebook Thermodynamics (7th edition) Part 1

V
^cr
WR
V
0
V

V
Vavg
W
w

w
wm

w out

Wrev
X
X

X
•^dest
-^fdest
-^dest

y
z
z
Z*
z,

Specific volume, m3/kg
Critical specific volume, m3/kg
Relative specific volume
Pseudoreduced specific volume
Total volume, m3
Volume flow rate, m3/s
Voltage, V
Velocity, m/s
Average velocity
Work per unit mass, kJ/kg
Total work, kJ
Power, kW
Work input, kJ
Work output, kJ
Reversible work, kJ
Quality
Specific exergy, kJ/kg
Total exergy, kJ
Specific exergy destruction, kJ/kg
Total exergy destruction, kJ
Rate of total exergy destruction, kW
Mole fraction
Elevation, m
Compressibility factor
Enthalpy departure factor
Entropy departure factor

Greek Letters
a

a
P
A
e
Vth
Vu

e
Mjt

f1
V
P
a
an
Vs
4>

Absorptivity
Isothermal compressibility, 1/kPa
Volume expansivity, 1/K
Finite change in quantity
Emissivity; effectiveness
Thermal efficiency
Second-law efficiency
Total energy of a flowing fluid, kJ/kg
Joule-Thomson coefficient, K/kPa
Chemical potential, kJ/kg
Stoichiometric coefficient
Density, kg/m3

Stefan-Boltzmann constant
Normal stress, N/m2
Surface tension, N/m
Relative humidity

<S>
O)

Specific closed system exergy, kJ/kg
Total closed system exergy, kJ
Stream exergy, kJ/kg
Specific or absolute humidity,
kg H20 /k g dry air

subscripts
a
abs
act
atm
avg
c
cr
CV
e
f
fg
g
gen

H
i
i
L
m
r
R
rev
s
sat
surr
sys
V

0
1
2

Air
Absolute
Actual
Atmospheric
Average
Combustion; cross-section
Critical point
Control volume
Exit conditions
Saturated liquid
Difference in property between saturated
and saturated vapor

Saturated vapor
Generation
High temperature (as in TH and QH)
Inlet conditions
ith component
Low temperature (as in TL and QL)
Mixture
Relative
Reduced
Reversible
Isentropic
Saturated
Surroundings
System
Water vapor
Dead state
Initial or inlet state
Final or exit state

Superscripts
(over dot)
(over bar)
0 (circle)
* (asterisk)

Quantity per unit time
Quantity per unit mole
Standard reference state
Quantity at 1 atm pressure

THERMODYNAMICS
AN E N G IN E E R IN G APPRO ACH

S E V EN TH E D IT IO N


THERMODYNAMICS
AN E N G IN E E R IN G APPRO ACH

SE V EN TH E D IT IO N

M IC HAEL A.
BOLES
North Carolina State
University

\Connect

Me
\ Learn
Grain/ 1 Succeed
Hill


The M cG raw -H ill Companies

Me
Graw
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THERMODYNAMICS: AN ENGINEERING APPROACH, SEVENTH EDITION
Published by McGraw-Hill, a business unit of The McGraw-Hill Companies, Inc., 1221 Avenue of the Americas,
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Library of Congress Cataloging-in-Publication Data
Cengel, Yunus A.
Thermodynamics: an engineering approach / Yunus A. Cengel, Michael A. Boles.— 7th ed.
p. cm.
ISBN-13: 978-0-07-352932-5 (hardcover : alk. paper)
ISBN-10: 0-07-352932-X (hardcover: alk. paper)
1. Thermodynamics. I. Boles, Michael A. II. Title.
TJ265.C43 2011
621.402'!—dc22

2009040824

The Internet addresses listed in the text were accurate at the time of publication. The inclusion of a Web site does
not indicate an endorsement by the authors or McGraw-Hill, and McGraw-Hill does not guarantee the accuracy
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A bout

th e

A uthors

Yunus A. Qengel

is Professor Emeritus of Mechanical Engineering at
the University of Nevada, Reno. He received his B.S. in mechanical engineer­
ing from Istanbul Technical University and his M.S. and Ph.D. in mechanical
engineering from North Carolina State University. His areas of interest are
renewable energy, energy efficiency, energy policies, heat transfer enhance­
ment, and engineering education. He served as the director of the Industrial
Assessment Center (IAC) at the University of Nevada, Reno, from 1996 to
2000. He has led teams of engineering students to numerous manufacturing
facilities in Northern Nevada and California to perform industrial assess­
ments, and has prepared energy conservation, waste minimization, and pro­
ductivity enhancement reports for them. He has also served as an advisor for
various government organizations and corporations.

Dr. Qengel is also the author or coauthor of the widely adopted text­
books Fundamentals o f Thermal-Fluid Sciences (3rd ed., 2008), Heat and
Mass Transfer: Fundamentals and Applications (4th ed., 2011), Introduction
to Thermodynamics and Heat Transfer (2nd ed., 2008), Fluid Mechanics:
Fundamentals and Applications (2nd ed., 2010), and Essentials o f Fluid
Mechanics: Fundamentals and Applications (1st ed., 2008), all published by
McGraw-Hill. Some of his textbooks have been translated into Chinese,
Japanese, Korean, Thai, Spanish, Portuguese, Turkish, Italian, Greek, and
French.
Dr. Qengel is the recipient of several outstanding teacher awards, and he
has received the ASEE Meriam/Wiley Distinguished Author Award for excel­
lence in authorship in 1992 and again in 2000. Dr. Qengel is a registered Pro­
fessional Engineer in the State of Nevada, and is a member of the American
Society of Mechanical Engineers (ASME) and the American Society for
Engineering Education (ASEE).

Michael A. Boles is Associate Professor of Mechanical and Aerospace
Engineering at North Carolina State University, where he earned his Ph.D. in
mechanical engineering and is an Alumni Distinguished Professor. Dr. Boles
has received numerous awards and citations for excellence as an engineering
educator. He is a past recipient of the SAE Ralph R. Teetor Education Award
and has been twice elected to the NCSU Academy of Outstanding Teachers.
The NCSU ASME student section has consistently recognized him as the out­
standing teacher of the year and the faculty member having the most impact
on mechanical engineering students.
Dr. Boles specializes in heat transfer and has been involved in the analyti­
cal and numerical solution of phase change and drying of porous media. He is
a member of the American Society of Mechanical Engineers (ASME), the
American Society for Engineering Education (ASEE), and Sigma Xi.
Dr. Boles received the ASEE MeriamAViley Distinguished Author Award in

1992 for excellence in authorship.


B rief
CHAPTER

C ontents

ONE

INTRODUCTION AND BASIC CONCEPTS

CHAPTER

1

TWO

ENERGY, ENERGY TRANSFER, AND GENERAL ENERGY ANALYSIS

CHAPTER

THREE

PROPERTIES OF PURE SUBSTANCES

CHAPTER

111

FOUR

ENERGY ANALYSIS OF CLOSED SYSTEMS

CHAPTER

163

FIVE

MASS AND ENERGY ANALYSIS OF CONTROL VOLUMES

CHAPTER

SIX

THE SECOND LAW OF THERMODYNAMICS

CHAPTER
ENTROPY

277

SEVEN

331

CHAPTER

EIGHT

EXERGY: A MEASURE OF WORK POTENTIAL

CHAPTER

NINE

GAS POWER CYCLES

CHAPTER

487

TEN

VAPOR AND COMBINED POWER CYCLES

CHAPTER

555

ELEVEN

REFRIGERATION CYCLES

CHAPTER

423

611

TWELVE

THERMODYNAMIC PROPERTY RELATIONS

CHAPTER

THIRTEEN

GAS MIXTURES

693

CHAPTER

FOURTEEN

661

GAS-VAPOR MIXTURES AND AIR-CONDITIONING

CHAPTER

FIFTEEN

CHEMICAL REACTIONS

CHAPTER

767

SIXTEEN

CHEMICAL AND PHASE EQUILIBRIUM

CHAPTER

813

SEVENTEEN

COMPRESSIBLE FLOW

APPENDIX

847

1

PROPERTY TABLES AND CHARTS (SI UNITS)

APPENDIX

731

907

2

PROPERTY TABLES AND CHARTS (ENGLISH UNITS)

957

215

51


Preface

xvii

Sum m ary 38
References and Suggested Readings
Problems 39

CHAPTER

ONE

INTRODUCTION AND BASIC CONCEPTS
1-1
1 -2

Thermodynamics and Energy

2

Application Areas of Therm odynam ics

3

Importance of Dimensions and Units

1

CHAPTER

1 -3

Systems and Control Volumes

1 -4

Properties of a System

1 -5

ENERGY ANALYSIS

3

1 -6
1 -7

Forms of Energy

State and Equilibrium

13

14

2 -4

15

Processes and Cycles

2 -5

16

60

Historical Background on Heat

61

Energy Transfer by Work

2 -6

Variation of Pressure with Depth

23

26

Other Pressure Measurem ent Devices

28

2 -7

1-11 The Barometer and Atmospheric Pressure
1 -1 2 Problem-Solving Technique

Step 1: Problem Statement 33
Step 2: Schematic 33
Step 3: Assum ptions and Approximations 33
Step 4: Physical Laws 34
Step 5: Properties 34
Step 6: Calculations 34
Step 7: Reasoning, Verification, and Discussion
Engineering Software Packages 35
Engineering Equation Solver (EES) 36
A Remark on Significant Digits 37

29

62

65

Mechanical Forms of Work

66

The First Law of Thermodynamics

70

Energy Balance 71
Energy Change of a System, AEsystem 72
M echanism s of Energy Transfer, £j„and Eout

73

Energy Conversion Efficiencies

78

Efficiencies of Mechanical and Electrical Devices

2 -8

33

55

Shaft Work 66
Spring Work 67
Work Done on Elastic Solid Bars 67
Work Associated w ith the Stretching of a Liquid Film
Work Done to Raise or to Accelerate a Body 68
Nonm echanical Forms of Work 69

20

21

1 -1 0 The Manometer

53

Energy Transfer by Heat

Electrical Work

15

Temperature and the Zeroth Law
of Thermodynamics 17

Pressure

52

Some Physical Insight to Internal Energy
More on N uclear Energy 56
Mechanical Energy 58

Temperature Scales 18
The International Temperature Scale of 1990 (ITS-90)

1- 9

2 -2

2 -3

The Steady-Fiow Process

1- 8

Introduction

10

13

The State Postulate

51

2 -1

12

Density and Specific Gravity

TWO

ENERGY, ENERGY TRANSFER, AND GENERAL

Some SI and English Units 6
Dimensional Homogeneity 8
Unity Conversion Ratios 9

Continuum

39

Energy and Environment

86

Ozone and Smog 87
Acid Rain 88
The Greenhouse Effect: Global W arm ing
and Climate Change 89

34

Topic o f Special Interest:
Mechanisms of Heat Transfer
Sum m ary 96
References and Suggested Readings
Problems 98

92
97

82

68


X

CONTENTS

CHAPTER

THREE

PROPERTIES OF PURE SUBSTANCES
3 -1

Pure Substance

3 -2

Phases of a Pure Substance

3 -3

Phase-Change Processes
of Pure Substances 113

111

4 -2

Energy Balance for Closed Systems

4 -3

Specific Heats

4 -4

Internal Energy, Enthalpy, and Specific Heats
of Ideal Gases 176

112
4 -5

3 -5

Property Tables

Sum m ary 195
References and Suggested Readings
Problems 196

3 -7
3 -8

CHAPTER
VO LUM ES
5 -1

134

5 -2

141

5 -4

Some Steady-Flow Engineering Devices
1 Nozzles and Diffusers 230
2 Turbines and Compressors 233
3 Throttling Valves 235
4a M ixing Chambers 237
4b Heat Exchangers 238
5 Pipe and Duct Flow 241

151

FOUR

Moving Boundary Work
Polytropic Process

168

164

Flow Work and the Energy of a Flowing
Fluid 223

Energy Analysis of Steady-Flow
Systems 226

5 -5

4 -1

219

5 -3

Topic o f Special Interest: Vapor Pressure
and Phase Equilibrium 146

ENERGY ANALYSIS OF CLOSED S Y S TE M S

216

Total Energy of a Flowing Fluid 223
Energy Transport by Mass 224

Van der Waals Equation of State 141
Beattie-Bridgem an Equation of State 142
Benedict-W ebb-Rubin Equation of State 143
Virial Equation of State 143

CHAPTER

Conservation of Mass

Mass and Volume Flow Rates 216
Conservation of Mass Principle 218
Mass Balance for Steady-Flow Processes
Special Case: Incom pressible Flow 220

137

Sum m ary 150
References and Suggested Readings
Problems 151

215

125

Compressibility Factor— A Measure of
Deviation from Ideal-Gas Behavior 137
Other Equations of State

FIVE

M A SS AND ENERGY ANALYSIS OF CONTROL

The Ideal-Gas Equation of State
Is Water Vapor an Ideal Gas?

195

120

124

Enthalpy— A Combination Property 124
la Saturated Liquid and Saturated Vapor States
lb Saturated Liquid-Vapor Mixture 127
2 Superheated Vapor 130

3 Compressed Liquid 131
Reference State and Reference Values 132

3 -6

184

Topic o f Special Interest: Thermodynamic
Aspects of Biological Systems 187

Property Diagrams for Phase-Change
Processes 118
1 The T-v Diagram 118
2 The P-v Diagram 120
Extending the Diagrams to Include the Solid Phase
3 The P -TD iag 122
The P -v-T Surface 123

178

Internal Energy, Enthalpy, and Specific Heats
of Solids and Liquids 183
Internal Energy Changes
Enthalpy Changes 184

Compressed Liquid and Saturated Liquid 114
Saturated Vapor and Superheated Vapor 114
Saturation Temperature and Saturation Pressure 115
Some Consequences of Tsat and Psat Dependence 116

3 -4

174

Specific Heat Relations of Ideal Gases

112

169

163

Energy Analysis of Unsteady-Flow
Processes 242
Topic o f Special Interest: General Energy
Equation 247
Sum m ary 251
References and Suggested Readings
Problems 252

252

229


xi

CONTENTS

CHAPTER

7 -2

SIX

THE SECOND LAW OF TH E R M O D Y N A M IC S
6 -1

Introduction to the Second Law

6 -2

Thermal Energy Reservoirs

6 -3

Heat Engines

277

278

279

280

Thermal Efficiency 281
Can We Save Qout? 283
The Second Law of Therm odynam ics: K elvin-Planck
Statement 285

6 -4

Refrigerators and Heat Pumps

Coefficient of Performance 286
Heat Pumps 287
Performance of Refrigerators, Air-Conditioners,
and Heat Pumps 288
The Second Law of Therm odynam ics: Clausius
Statement 290
Equivalence of the Two Statements 291

Perpetual-Motion Machines

6-6

Reversible and Irreversible Processes

6-8

The Carnot Principles

6 -9

The Thermodynamic Temperature Scale

7 -5

Property Diagrams Involving Entropy

7 -6

What Is Entropy?

339

342
344

345

7 -7

The T ds Relations

7 -8

Entropy Change of Liquids
and Solids 350

7 -9

The Entropy Change of Ideal Gases

347

349

354

Constant Specific Heats
(Approximate Analysis) 354
Variable Specific Heats (Exact Analysis) 355
Isentropic Processes of Ideal Gases 357
Constant Specific Heats
(Approximate Analysis) 357
Variable Specific Heats (Exact Analysis) 358
Relative Pressure and Relative
Specific Volume 358

361

Proof that Steady-Flow Devices Deliver the Most
and Consume the Least Work When the Process
Is Reversible 364

299

6 - 1 0 The Carnot Heat Engine

299

7 -1 1
301

Multistage Compression with Intercooling

Devices

305

6 -1 1 The Carnot Refrigerator and Heat Pump
Topic o f Special Interest: Household
Refrigerators 309
Sum mary 313
References and Suggested Readings
Problems 314

Minimizing the Compressor Work

364
366

7 - 1 2 Isentropic Efficiencies of Steady-Flow

303

The Quality of Energy 305
Quantity versus Quality in Daily Life

314

SEVEN

331

Entropy

Isentropic Processes

297

The Reversed Carnot Cycle

7 -1

7 -4

7 - 1 0 Reversible Steady-Flow Work

297

The Carnot Cycle

ENTROPY

Entropy Change of Pure Substances

294

6 -7

338

7 -3

292

Irreversibilities 295

Internally and Externally Reversible Processes

CHAPTER

Some Remarks about Entropy

335

Entropy and Entropy Generation in Daily Life

285

6 -5

The Increase of Entropy Principle

332

A Special Case: Internally Reversible Isothermal Heat
Transfer Processes 334

306

368

Isentropic Efficiency of Turbines 369
Isentropic Efficiencies of Compressors
and Pumps 371
Isentropic Efficiency of Nozzles 373

7 - 1 3 Entropy Balance

375

Entropy Change of a System, ASsystem 375
M echanism s of Entropy Transfer, Sin and Sout 376
1 Heat Transfer 376
2 Mass Flow 377
Entropy Generation, Sgen 377
Closed Systems 378
Control Volumes 379
Entropy Generation Associated with a Heat Transfer
Process 386

Topic o f Special Interest: Reducing the Cost
of Compressed Air 387
Sum mary 396
References and Suggested Readings
Problems 398

397


CHAPTER

EIGHT

EXERGY: A M EASURE OF W ORK
POTENTIAL
8 -1

423

Exergy: Work Potential of Energy

424

Exergy (Work Potential) Associated with Kinetic
and Potential Energy 425

8 -2

Reversible Work and Irreversibility

8 -3

Second-Law Efficiency, %

432

8 -4

Exergy Change of a System

435

8 -5

Otto Cycle: The Ideal Cycle
for Spark-Ignition Engines 494

9 -6

Diesel Cycle: The Ideal Cycle
for Compression-Ignition Engines

9 -7

Stirling and Ericsson Cycles

9 -8

Brayton Cycle: The Ideal Cycle
for Gas-Turbine Engines 507

427

500

503

Development of Gas Turbines 510
Deviation of Actual Gas-Turbine Cycles
from Idealized Ones 513

9 -9

The Brayton Cycle with Regeneration

Exergy of a Fixed Mass: Nonflow (or Closed System)

Exergy 435
Exergy of a Flow Stream: Flow (or Stream) Exergy 438

9 - 1 0 The Brayton Cycle with Intercooling,

Exergy Transfer by Heat, Work,
and Mass 440

9 -1 1 Ideal Jet-Propulsion Cycles

514

517
521
525

9 - 1 2 Second-Law Analysis of Gas
Power Cycles

The Decrease of Exergy Principle and Exergy
Destruction 443
Exergy Destruction

Reheating, and Regeneration

M odifications to Turbojet Engines

Exergy by Heat Transfer, Q 441
Exergy Transfer by Work, W 442
Exergy Transfer by Mass, m 442

8-6

9 -5

444

8 -7

Exergy Balance: Closed Systems

8-8

Exergy Balance: Control Volumes

Topic o f Special Interest: Saving Fuel
and Money by Driving Sensibly 531
Sum mary 537
References and Suggested Readings
Problems 539

445

539

456

Exergy Balance for Steady-Flow Systems 457
Reversible Work, Wm 458
Second-Law Efficiency of Steady-Flow Devices, rjM 458

CHAPTER

TEN

VAPOR AND CO M BINED POWER

Topic o f Special In terest: Second-Law
Aspects of Daily Life 465
Sum m ary 469
References and Suggested Readings
Problems 470

527

CYCLES

555

1 0 -1 The Carnot Vapor Cycle

470

556

1 0 - 2 Rankine Cycle: The Ideal Cycle for Vapor
Power Cycles

557

Energy Analysis of the Ideal Rankine Cycle

CHAPTER
GAS POW ER CYCLES

NINE

557

1 0 -3 Deviation of Actual Vapor Power Cycles
from Idealized Ones

487

9 -1

Basic Considerations in the Analysis
of Power Cycles 488

9 -2

The Carnot Cycle and Its Value
in Engineering 490

9 -3

Air-Standard Assumptions

9 -4

An Overview of Reciprocating Engines

560

1 0 - 4 How Can We Increase the Efficiency
of the Rankine Cycle?

563

Lowering the Condenser Pressure
(Lowers 7;owavg) 563
Superheating the Steam to High Temperatures
(Increases rhighavg) 564
Increasing the Boiler Pressure

492

(Increases rhighavg)

492

564

1 0 -5 The Ideal Reheat Rankine Cycle

567


xiii

CONTENTS

1 0 - 6 The Ideal Regenerative Rankine Cycle

571

Open Feedwater Heaters 571
Closed Feedwater Heaters 573

579

1 0 -8 Cogeneration

581

RELATIONS

1 2 -2

592

Internal Energy Changes
Enthalpy Changes 672
Entropy Changes 673
Specific Heats cv and cp

668

672

674

678

1 2 -6 The Ah, Au, and As of Real
Gases 680

612
613

614

1 1 - 4 Actual Vapor-Compression Refrigeration

Enthalpy Changes of Real Gases 680
Internal Energy Changes of Real Gases
Entropy Changes of Real Gases 682
Sum mary 685
References and Suggested Readings
Problems 686

681

686

617

1 1 -5 Second-Law Analysis of Vapor-Compression
Refrigeration Cycle

11 -6

667

1 2 -5 The Joule-Thomson Coefficient

611

1 1 -3 The Ideal Vapor-Compression Refrigeration

Cycle

The Maxwell Relations

1 2 - 4 General Relations for du, dh, ds, cy and cp

ELEVEN

1 1 -1 Refrigerators and Heat Pumps

Cycle

665

1 2 -3 The Clapeyron Equation

Sum mary 592
References and Suggested Readings
Problems 593

1 1 -2 The Reversed Carnot Cycle

Partial Differentials 663
Partial Differential Relations

586

Topic o f Special Interest: Binary
Vapor Cycles 589

REFRIGERATION CYCLES

661

12-1 A Little Math— Partial Derivatives
and Associated Relations 662

1 0 - 9 Combined Gas-Vapor Power Cycles

CHAPTER

TWELVE

TH E R M O D Y N A M IC PROPERTY

1 0 -7 Second-Law Analysis of Vapor
Power Cycles

CHAPTER

619

Selecting The Right Refrigerant

1 1 -7 Heat Pump Systems

624

CHAPTER
GAS M IX TU R E S

THIRTEEN
693

13-1 Composition of a Gas Mixture: Mass
and Mole Fractions 694

626

1 1 - 8 Innovative Vapor-Compression Refrigeration
Systems

627

Cascade Refrigeration Systems 628
Multistage Compression Refrigeration Systems 630
M ultipurpose Refrigeration Systems with a Single
Compressor 632
Liquefaction of Gases 633

11 - 9 Gas Refrigeration Cycles

634

1 1 -1 0 Absorption Refrigeration Systems

637

1 3 -2 P -v-T Behavior of Gas Mixtures: Ideal
and Real Gases 696
Ideal-Gas Mixtures
Real-Gas M ixtures

697
697

1 3 -3 Properties of Gas Mixtures: Ideal
and Real Gases 701
Ideal-Gas Mixtures
Real-Gas Mixtures

702
705

Topic o f Special Interest: Thermoelectric
Power Generation and Refrigeration
Systems 640

Topic o f Special Interest: Chemical
Potential and the Separation Work

of Mixtures 709

Sum mary 642
References and Suggested Readings
Problems 643

Sum m ary 720
References and Suggested Readings
Problems 721

643

721

671


xiv

CONTENTS

CHAPTER

CHAPTER

FOURTEEN

G AS-VA PO R M IX TU R E S
AND A IR -C O N D ITIO N IN G

SIXTEEN

CH EM IC AL AND PHASE EQ U ILIB R IU M
731
1 6 -1 Criterion for Chemical Equilibrium

1 4 -1 Dry and Atmospheric Air

732

1 4 - 3 Dew-Point Temperature

Mixtures

733

Mixtures

1 4 - 4 Adiabatic Saturation and Wet-Bulb

Reactions
740

824

1 6 - 5 Variation of Kp with Temperature

1 4 - 6 Human Comfort and Air-Conditioning

741

1 6 -6 Phase Equilibrium

743

Simple Heating and Cooling (<« = constant)
Heating with H um idification 745
Cooling with Dehum idification 746
Evaporative Cooling 748
Adiabatic M ixing of Airstreams 749
Wet Cooling Towers 751
Sum m ary 753
References and Suggested Readings
Problems 755

820

1 6 - 4 Chemical Equilibrium for Simultaneous

737

1 4 - 7 Air-Conditioning Processes

816

1 6 - 3 Some Remarks about the Kp of Ideal-Gas

735

1 4 - 5 The Psychrometric Chart

Phase Equilibrium for a Single-Component System 828
The Phase Rule 830
Phase Equilibrium for a M ulticom ponent System 830

744

Sum mary 836
References and Suggested Readings
Problems 837

755

CHAPTER

FIFTEEN

CH EM IC A L REACTIONS
1 5 -1 Fuels and Combustion

767

847
848

1 7 -2 Speed of Sound and Mach Number
1 7 - 3 One-Dimensional Isentropic Flow

768

1 7 - 4 Isentropic Flow Through Nozzles

1 5 - 3 Enthalpy of Formation and Enthalpy

Converging Nozzles 860
C onverging-Diverging Nozzles

779

1 5 - 4 First-Law Analysis of Reacting Systems

782

788

1 5 - 6 Entropy Change of Reacting Systems

Sum mary 800
References and Suggested Readings
Problems 801

801

858

860

869

880

1 7 - 6 Duct Flow with Heat Transfer and Negligible
Friction (Rayleigh Flow)

790

1 5 -7 Second-Law Analysis of Reacting Systems
Topic o f Special Interest: Fuel Cells

853

865

1 7 - 5 Shock Waves and Expansion Waves
Normal Shocks 869
Oblique Shocks 876
P randtl-M eyer Expansion Waves

Steady-Flow Systems 783
Closed Systems 784

1 5 - 5 Adiabatic Flame Temperature

851

Variation of Fluid Velocity with Flow Area 856
Property Relations for Isentropic Flow of Ideal Gases

772

of Combustion

837

SEVENTEEN

1 7 -1 Stagnation Properties

1 5 -2 Theoretical and Actual Combustion
Processes

826

828

COM PRESSIBLE FLOW

CHAPTER

814

1 6 -2 The Equilibrium Constant for Ideal-Gas

1 4 - 2 Specific and Relative Humidity of Air

Temperatures

813

798

792

884

Property Relations for Rayleigh Flow
Choked Rayleigh Flow 891

1 7 -7 Steam Nozzles

890

893

Sum m ary 896
References and Suggested Readings
Problems 898

897


XV

CONTENTS

APPENDIX

1

PROPERTY TABLES AND CHARTS

(S I U N IT S )
907
TABLE A-1

Molar mass, gas constant,
and critical-point properties

908

TABLE A -2 6

Enthalpy of formation, Gibbs function
of formation, and absolute entropy
at 25°C, 1 atm 948

TABLE A -2 7

Properties of some common fuels and
hydrocarbons 949

TABLE A - 2 8

Natural logarithms of the equilibrium
constant Kp 950

TABLE A -2

Ideal-gas specific heats of various
common gases 909

FIGURE A - 2 9 Generalized enthalpy departure

TABLE A -3

Properties of common liquids, solids,
and foods 912

FIGURE A -3 0 Generalized entropy departure

TABLE A - 4

Saturated water— Temperature
table 914

FIGURE A—31 Psychrometric chart at 1 atm total

TABLE A -5

S aturated water— Pressure table

TABLE A -6

Superheated water

TABLE A -7

Compressed liquid water

TABLE A -8

Saturated ice-w ater vapor

FIGURE A -9

T-s diagram for water

chart
chart

951
952

pressure
916

TABLE A -3 2

918
922

953

One -dimensional isentropic
compressible-flow functions
for an ideal gas with k = 1.4

954

923

TABLE A -3 3

FIGURE A -1 0 Mollier diagram for water 925
TABLE A - 1 1 Saturated refrigerant-134a—

One -dimensional normal-shock
functions for an ideal gas with
k = 1.4 955

TABLE A -3 4

Rayleigh flow functions for an ideal gas
with k = 1.4 956

Temperature table

TABLE A -1 2

924

926

Saturated refrigerant-134a— Pressure
table 928

TABLE A - 1 3 Superheated refrigerant-134a 929
FIGURE A -1 4 P-h diagram for refrigerant-134a 931
FIGURE A -1 5 Nelson-Obert generalized
compressibility chart

TABLE A -1 6
TABLE A -1 7
TABLE A - 1 8

PROPERTY TABLES AND CHARTS
(ENG LISH U N IT S )
957

Properties of the atmosphere at high
altitude 933

TABLE A -1 E

Molar mass, gas constant,
and critical-point properties

Ideal-gas properties of air

934

TABLE A -2E

Ideal-gas properties of nitrogen,
N2 936

Ideal-gas specific heats of various
common gases 959

TABLE A -3E

Properties of common liquids, solids,
and foods 962

TABLE A -4E

Saturated water— Temperature
table 964

TABLE A -5E

Saturated water— Pressure
table 966

TABLE A -6E
TABLE A -7E

Superheated water

TABLE A -8E

Saturated ice— water vapor

Ideal-gas properties of oxygen, 0 2 938

TABLE A -2 0

Ideal-gas properties of carbon dioxide,
C 0 2 940

TABLE A -21

Ideal-gas properties of carbon
monoxide, CO 942

TABLE A -2 2

Ideal-gas properties of hydrogen,
H2 944

TABLE A -2 3

Ideal-gas properties of water vapor,
H20 945

TABLE A -2 5

2

932

TABLE A - 1 9

TABLE A -2 4

APPENDIX

Ideal-gas properties of monatomic
oxygen, O 947
Ideal-gas properties of hydroxyl,
OH 947

958

968

Compressed liquid water

972
973

FIGURE A -9E T-s diagram for water 974
FIGURE A -1 0 E Mollier diagram for water 975
TABLE A - 1 1E Saturated refrigerant-134a—
Temperature table

976


xvi

CONTENTS

TABLE A -1 2 E

Saturated refrigerant-134a— Pressure
table 977

TABLE A -2 2 E

Ideal-gas properties of hydrogen,

H2 992

TABLE A -1 3 E

Superheated refrigerant-134a

TABLE A -2 3 E

Ideal-gas properties of water vapor,
H20 993

TABLE A -2 6 E

Enthalpy of formation, Gibbs function
of formation, and absolute entropy at
77°F, 1 atm 995

TABLE A -2 7 E

Properties of some common fuels
and hydrocarbons 996

978

FIGURE A -1 4 E P-h diagram for refrigerant- 134a

980

TABLE A -1 6 E

Properties of the atmosphere at high
altitude 981

TABLE A -1 7 E

Ideal -gas properties of air

TABLE A -1 8 E

Ideal-gas properties of nitrogen,
N2 984

TABLE A -1 9 E

Ideal-gas properties of oxygen,
0 2 986

TABLE A -2 0 E

Ideal-gas properties of carbon dioxide,
C 0 2 988

TABLE A -2 1 E

Ideal -gas properties of carbon
monoxide, CO 990

982

FIGURE A -3 1 E Psycrometric chart at 1 atm total

pressure
Index

999

997


P

r

e

f

a

c

e

U

BACKGROUND
Thermodynamics is an exciting and fascinating subject that deals with energy,
which is essential for sustenance of life, and thermodynamics has long been
an essential part of engineering curricula all over the world. It has a broad
application area ranging from microscopic organisms to common household
appliances, transportation vehicles, power generation systems, and even phi­

losophy. This introductory book contains sufficient material for two sequen­
tial courses in thermodynamics. Students are assumed to have an adequate
background in calculus and physics.

OBJECTIVES
This book is intended for use as a textbook by undergraduate engineering stu­
dents in their sophomore or junior year, and as a reference book for practicing
engineers. The objectives of this text are
• To cover the basic principles of thermodynamics.
• To present a wealth of real-world engineering examples to give
students a feel for how thermodynamics is applied in engineering
practice.
• To develop an intuitive understanding of thermodynamics by empha­
sizing the physics and physical arguments.
It is our hope that this book, through its careful explanations of concepts and
its use of numerous practical examples and figures, helps students develop the
necessary skills to bridge the gap between knowledge and the confidence to
properly apply knowledge.

PHILOSOPHY

AND

GOAL

The philosophy that contributed to the overwhelming popularity of the prior
editions of this book has remained unchanged in this edition. Namely, our
goal has been to offer an engineering textbook that
• Communicates directly to the minds of tomorrow’s engineers in a
simple yet precise manner.

• Leads students toward a clear understanding and firm grasp of the
basic principles of thermodynamics.
• Encourages creative thinking and development of a deeper understand­
ing and intuitive fe e l for thermodynamics.
• Is read by students with interest and enthusiasm rather than being used
as an aid to solve problems.
Special effort has been made to appeal to students’ natural curiosity and to help
them explore the various facets of the exciting subject area of thermodynamics.
The enthusiastic responses we have received from users of prior editions—
from small colleges to large universities all over the world— and the continued


xviii

PREFACE

translations into new languages indicate that our objectives have largely been
achieved. It is our philosophy that the best way to learn is by practice. There­
fore, special effort is made throughout the book to reinforce material that was
presented earlier.
Yesterday’s engineer spent a major portion of his or her time substituting val­
ues into the formulas and obtaining numerical results. However, formula
manipulations and number crunching are now being left mainly to computers.
Tomorrow’s engineer will need a clear understanding and a firm grasp of the
basic principles so that he or she can understand even the most complex prob­
lems, formulate them, and interpret the results. A conscious effort is made to
emphasize these basic principles while also providing students with a perspec­
tive of how computational tools are used in engineering practice.
The traditional classical, or macroscopic, approach is used throughout the
text, with microscopic arguments serving in a supporting role as appropriate.

This approach is more in line with students’ intuition and makes learning the
subject matter much easier.

NEW

IN T H I S

EDITION

The primary change in this seventh edition of the text is the upgrade of a large
number of line artwork to realistic three-dimensional figures and the incorpo­
ration of about 400 new problems. All the popular features of the previous
editions are retained, and the main body of all chapters and all the tables and
charts in the Appendices remain mostly unchanged. Each chapter now contains
at least one new solved example problem, and a significant part of existing
problems are modified. In Chapter 1, the section on Dimensions and Units is
updated, and a new subsection is added to Chapter 6 on the Performance of
Refrigerators, Air-Conditioners, and Heat Pumps. In Chapter 8, the material
on the second-law efficiency is updated, and some second-law efficiency
definitions are revised for consistency. Also, the discussions in the section
Second-Law Aspects of Daily Life have been extended. Chapter 11 now has a
new section titled Second-Law Analysis of Vapor-Compression Refrigeration
Cycle.

OVER 4 0 0 NEW PROBLEMS
This edition includes over 400 new problems with a variety of applications.
Problems whose solutions require param etric investigations, and thus the
use o f a computer, are identified by a computer-EES icon, as before. Some
existing problems from previous editions have been removed from the text.

LEARNING

TOOLS

EARLY INTRODUCTIO N OF THE FIRST LAW OF T H E R M O D Y N A M IC S
The first law of thermodynamics is introduced early in Chapter 2, “Energy,
Energy Transfer, and General Energy Analysis.” This introductory chapter
sets the framework of establishing a general understanding of various forms
of energy, mechanisms of energy transfer, the concept of energy balance,
therm o-econom ics, energy conversion, and conversion efficiency using fa­
m iliar settings that involve mostly electrical and mechanical forms of
energy. It also exposes students to some exciting real-world applications
of thermodynamics early in the course, and helps them establish a sense of


xix

PREFACE

the monetary value of energy. There is special emphasis on the utilization of
renewable energy such as wind power and hydroulic energy, and the effi­
cient use of existing resources.

E M P H A S IS ON PH YSIC S
A distinctive feature of this book is its emphasis on the physical aspects of the
subject matter in addition to mathematical representations and manipulations.
The authors believe that the emphasis in undergraduate education should
remain on developing a sense o f underlying physical mechanisms and a mas­
tery o f solving practical problems that an engineer is likely to face in the real
world. Developing an intuitive understanding should also make the course a

more motivating and worthwhile experience for students.

EFFECTIVE USE OF ASSOCIATION
An observant mind should have no difficulty understanding engineering sciences.
After all, the principles of engineering sciences are based on our everyday expe­
riences and experimental observations. Therefore, a physical, intuitive approach
is used throughout this text. Frequently, parallels are drawn between the subject
matter and students’ everyday experiences so that they can relate the subject mat­
ter to what they already know. The process of cooking, for example, serves as an
excellent vehicle to demonstrate the basic principles of thermodynamics.

SELF-IN STR UCTIN G
The material in the text is introduced at a level that an average student can fol­
low comfortably. It speaks to students, not over students. In fact, it is selfinstructive. The order of coverage is from simple to general. That is, it starts
with the simplest case and adds complexities gradually. In this way, the basic
principles are repeatedly applied to different systems, and students master
how to apply the principles instead of how to simplify a general formula. Not­
ing that the principles of sciences are based on experimental observations, all
the derivations in this text are based on physical arguments, and thus they are
easy to follow and understand.

EXTENSIVE USE OF ARTW ORK
Figures are important learning tools that help students “get the picture,” and the
text makes very effective use of graphics. This edition of Thermodynamics: An
Engineering Approach, Seventh Edition contains more figures and illustrations
than any other book in this category. Further, a large number of figures have
been upgraded to become three-dimensional and thus more real-life. Figures
attract attention and stimulate curiosity and interest. Most of the figures in this
text are intended to serve as a means of emphasizing some key concepts that
would otherwise go unnoticed; some serve as page summaries. The popular

cartoon feature “Blondie” is used to make some important points in a humorous
way and also to break the ice and ease the nerves. Who says studying thermo­
dynamics can’t be fun?

LEARNING OBJECTIVES AND S U M M A R IE S
Each chapter begins with an overview of the material to be covered and
chapter-specific learning objectives. A summary is included at the end of
each chapter, providing a quick review of basic concepts and important rela­
tions, and pointing out the relevance of the material.


XX

PREFACE

NU M ER O U S W ORKED-OUT EXAM PLES
W IT H A SY STE M A TIC SOLUTIONS PROCEDURE
Each chapter contains several worked-out examples that clarify the material and
illustrate the use of the basic principles. An intuitive and systematic approach is
used in the solution of the example problems, while maintaining an informal
conversational style. The problem is first stated, and the objectives are identified.
The assumptions are then stated, together with their justifications. The properties
needed to solve the problem are listed separately if appropriate. Numerical val­
ues are used together with their units to emphasize that numbers without units are
meaningless, and that unit manipulations are as important as manipulating the
numerical values with a calculator. The significance of the findings is discussed
following the solutions. This approach is also used consistently in the solutions
presented in the instructor’s solutions manual.

A W EALTH OF REAL-WORLD END-OF-CHAPTER PROBLEMS

The end-of-chapter problems are grouped under specific topics to make prob­
lem selection easier for both instructors and students. Within each group of
problems are Concept Questions, indicated by “C,” to check the students’ level
of understanding of basic concepts. The problems under Review Problems are
more comprehensive in nature and are not directly tied to any specific section
of a chapter— in some cases they require review of material learned in previous
chapters. Problems designated as Design and Essay are intended to encourage
students to make engineering judgm ents, to conduct independent exploration
of topics of interest, and to communicate their findings in a professional
manner. Problems designated by an “E” are in English units, and SI users can
ignore them. Problems with the @ are solved using EES, and complete solu­
tions together with parametric studies are included on the enclosed DVD.
Problems with the
are comprehensive in nature and are intended to be
solved with a computer, preferably using the EES software that accompanies
this text. Several economics- and safety-related problems are incorporated
throughout to enhance cost and safety awareness among engineering students.
Answers to selected problems are listed immediately following the problem for
convenience to students. In addition, to prepare students for the Fundamentals
of Engineering Exam (that is becoming more important for the outcome-based
ABET 2000 criteria) and to facilitate multiple-choice tests, over 200 multiplechoice problems are included in the end-of-chapter problem sets. They are
placed under the title Fundamentals o f Engineering (FE) Exam Problems for
easy recognition. These problems are intended to check the understanding of
fundamentals and to help readers avoid common pitfalls.

RELAXED SIGN CONVENTION
The use of a formal sign convention for heat and work is abandoned as it often
becomes counterproductive. A physically meaningful and engaging approach
is adopted for interactions instead of a mechanical approach. Subscripts “in”
and “out,” rather than the plus and minus signs, are used to indicate the direc­

tions of interactions.

PHYSICALLY M EAN IN G FUL FORMULAS
The physically meaningful forms of the balance equations rather than formu­
las are used to foster deeper understanding and to avoid a cookbook approach.


xx i

PREFACE

The mass, energy, entropy, and exergy balances for any system undergoing
any process are expressed as
Mass balance:

mia — mout

Energy balance:

Em — Eoui

^^system
=

N e t e n e r g y tr a n s f e r

C h a n g e in in te r n a l, k in e tic ,

b y h e a t, w o rk , a n d m a s s

Entropy balance:

Sm — Soat +
N e t e n tr o p y tr a n s f e r
by h eat an d m ass

Exergy balance:

X [n- X oM -

Sgen

AF

L * L -' s y s te m

p o te n tia l, e tc ., e n e rg ie s
—

E n tro p y
g e n e ra tio n

Xdestroyed =

ACs y s te m
C hange
in e n tro p y

AYs y s te m

N e t e x e r g y tr a n s f e r

E x e rg y

C hange

b y h e a t, w o r k , a n d m a s s

d e s tr u c tio n

in e x e rg y

These relations reinforce the fundamental principles that during an actual
process mass and energy are conserved, entropy is generated, and exergy is
destroyed. Students are encouraged to use these forms of balances in early chap­
ters after they specify the system, and to simplify them for the particular prob­
lem. A more relaxed approach is used in later chapters as students gain mastery.

A CHOICE OF SI ALONE OR SI/EN G LISH U N ITS
In recognition of the fact that English units are still widely used in some industries,
both SI and English units are used in this text, with an emphasis on SI. The mate­
rial in this text can be covered using combined SI/English units or SI units alone,
depending on the preference of the instructor. The property tables and charts in the
appendices are presented in both units, except the ones that involve dimensionless
quantities. Problems, tables, and charts in English units are designated by “E” after
the number for easy recognition, and they can be ignored by SI users.

TO PICS OF SPECIAL INTEREST
Most chapters contain a section called “Topic of Special Interest” where inter­
esting aspects of thermodynamics are discussed. Examples include Thermo­

dynamic Aspects o f Biological Systems in Chapter 4, Household Refrigerators
in Chapter 6, Second-Law Aspects o f Daily Life in Chapter 8, and Saving Fuel
and Money by Driving Sensibly in Chapter 9. The topics selected for these sec­
tions provide intriguing extensions to thermodynamics, but they can be
ignored if desired without a loss in continuity.

GLOSSARY OF TH E R M O D Y N A M IC TE R M S
Throughout the chapters, when an important key term or concept is introduced
and defined, it appears in boldface type. Fundamental thermodynamic terms and
concepts also appear in a glossary located on our accompanying website
(www.mhhe.com/cengel). This unique glossary helps to reinforce key terminol­
ogy and is an excellent learning and review tool for students as they move forward
in their study of thermodynamics. In addition, students can test their knowledge of
these fundamental terms by using the flash cards and other interactive resources.

CONVERSION FACTORS
Frequently used conversion factors and physical constants are listed on the
inner cover pages of the text for easy reference.


xxii

PREFACE

SUPPLEMENTS
The following supplements are available to users of the book.

STUDENT RESOURCE DVD
Engineering Equation Solver (EES)
Packaged free with every new text, the Student Resource DVD contains the

Limited Academic Version of EES (Engineering Equation Solver) software
with scripted solutions to selected text problems.
Developed by Sanford Klein and William Beckman from the University of
Wisconsin— Madison, this software combines equation-solving capability and
engineering property data. EES can do optimization, parametric analysis, and
linear and nonlinear regression, and provides publication-quality plotting capa­
bilities. Thermodynamics and transport properties for air, water, and many
other fluids are built in, and EES allows the user to enter property data or func­
tional relationships.
EES is a powerful equation solver with built-in functions and property
tables for thermodynamic and transport properties as well as automatic unit
checking capability. It requires less time than a calculator for data entry and
allows more time for thinking critically about modeling and solving engi­
neering problems. Look for the EES icons in the homework problems sec­
tions of the text.

PROPERTIES TABLE BOOKLET
(ISBN 0 -0 7 -7 3 5 9 9 9 -2 )
This booklet provides students with an easy reference to the most important
property tables and charts, many of which are found at the back of the text­
book in both the SI and English units.

COSMOS
M cGraw-Hill’s COSMOS (Com plete Online Solutions Manual Organiza­
tion System) allows instructors to streamline the creation of assignments,
quizzes, and tests by using problems and solutions from the textbook, as
well as their own custom material. COSMOS is now available online at
http://cosm os.m hhe.com /

HANDS-ON MECHANICS

Hands-on Mechanics is a website designed for instructors who are interested
in incorporating three-dimensional, hands-on teaching aids into their lectures.
Developed through a partnership between the McGraw-Hill Engineering
Team and the Department of Civil and Mechanical Engineering at the United
States Military Academy at West Point, this website not only provides detailed
instructions for how to build 3-D teaching tools using materials found in any
lab or local hardware store, but also provides a community where educators
can share ideas, trade best practices, and submit their own original demon­
strations for posting on the site. Visit www.handsonmechanics.com for more
information.


xxiii

PREFACE

ACKNOWLEDGMENTS
The authors would like to acknowledge with appreciation the numerous and
valuable comments, suggestions, constructive criticisms, and praise from the
following evaluators and reviewers:
E dw ard A nderson
Texas Tech University

Jo h n Biddle
Cal Poly Pomona University

G ianfranco DiGiuseppe
Kettering University

Shoeleh Di Julio

California State University-Northridge

A fshin G h a ja r
Oklahoma State University

H a rry H ardee
New Mexico State University

Kevin Lyons
North Carolina State University

Kevin M acfarlan
John Brown University

Saeed M anafzadeh
University o f Illinois-Chicago

Alex M outsoglou
South Dakota State University

Rishi Raj
The City College o f New York

M aria Sanchez
California State University-Fresno

K alyan Srinivasan
M ississippi State University

R o b ert Stiger

Gonzaga University

Their suggestions have greatly helped to improve the quality of this text. In par­
ticular we would like to express our gratitude to Mehmet Kanoglu of the Uni­
versity of Gaziantep, Turkey, for his valuable contributions, his critical review
of the manuscript, and for his special attention to accuracy and detail.
We also would like to thank our students, who provided plenty of feed­
back from students’ perspectives. Finally, we would like to express our
appreciation to our wives, Zehra (Tengel and Sylvia Boles, and to our chil­
dren for their continued patience, understanding, and support throughout the
preparation of this text.
Yunus A. Qengel
Michael A. Boles


Online Resources for the Student and Instructor
NEW TO THIS EDITION!
McGRAW-HILL CONNECT ENGINEERING
M c G ra w -H ill C o n n e ct E n g in e e rin g is a w eb-based a s s ig n m e n t and
assessm e nt p la tfo rm th a t gives s tu d e n ts th e m eans to b e tte r c o n n e c t w ith
th e ir cou rse w ork, w ith th e ir in s tru c to rs , and w ith th e im p o rta n t c o n c e p ts th a t
th e y w ill need to know fo r success now and in th e fu tu re . W ith C o n n e ct
E n g in e e rin g , in s tru c to rs can d e liv e r a s sig n m e n ts, quizzes, and te s ts e asily
o n lin e . S tu d e n ts can p ra c tic e im p o rta n t s k ills at th e ir ow n pace and on th e ir
own sch e d u le .
C o n n e ct E n g in e e rin g fo r Thermodynamics: An Engineering Approach,
S even th E d itio n is a v a ila b le via th e te x t w e b s ite at w w w .m h h e .c o m /c e n g e l

COSMOS
M c G ra w -H ill’s COSMOS (C om plete O n line S o lu tio n s M anual O rganization

S yste m ) a llo w s in s tru c to rs to s tre a m lin e th e c re a tio n of a s s ig n m e n ts ,
q u izze s, and te s ts by u sin g p ro b le m s and s o lu tio n s fro m th e te x tb o o k ,
as w e ll as th e ir ow n c u s to m m a te ria l. COSM O S is now a v a ila b le o n lin e
a t h ttp ://c o s m o s .m h h e .c o m /

W W W .M H H E.C O M /C EN G EL
T h is s ite o ffe rs resources fo r s tu d e n ts and in s tru c to rs .
The fo llo w in g resources are availa b le fo r stu d e n ts:
■ Glossary of Key Terms in Thermodynamics— B olded te rm s in th e te x t are
d e fin e d in th is acce ssib le glossary. O rganized at th e c h a p te r level or
a va ila b le as one large file .
■ Student Study Guide— T his resource o u tlin e s th e fu n d a m e n ta l c o n ce p ts of
th e te x t and is a h e lp fu l g u id e th a t allow s s tu d e n ts to fo c u s on th e m ost
im p o rta n t co n ce p ts. The g uide can also serve as a le c tu re o u tlin e fo r
in s tru c to rs .
■ Learning Objectives— The c h a p te r le a rn in g o b je c tiv e s are o u tlin e d here.
O rganized by c h a p te r and tie d to A B E T ob je ctive s.
■ Self-Quizzing— S tu d e n ts can te s t th e ir know ledge using m u ltip le -c h o ic e
q u izzin g . These s e lf-te s ts provide im m e d ia te fe e d b a c k and are an e x c e lle n t
le a rn in g to o l.
■ Flashcards— In te ra c tiv e fla s h c a rd s te s t s tu d e n t u n d e rs ta n d in g of th e te x t
te rm s and th e ir d e fin itio n s . The program also allow s s tu d e n ts to fla g te rm s
th a t re q u ire fu rth e r u n d e rs ta n d in g .
■ Crossword Puzzles— An in te ra c tiv e , tim e d puzzle th a t provides h in ts as w ell
as a notes se ctio n .


■ Concentration— An in te ra c tiv e m a tc h in g gam e th a t enhances u n d e rs ta n d in g o f basic
th e rm o d y n a m ic co nce p ts.
■ Errata— If errors shou ld be fo u n d in th e te x t, th e y w ill be reported here.

The fo llo w in g resources are a vailab le fo r in s tru c to rs under password pro te ctio n :
■ Instructor Testbank— A d d itio n a l p ro b le m s prepared fo r in s tru c to rs to assign to stu d e n ts.
S o lu tio n s are given, and use o f EES is re com m ended to ve rify accuracy.
■ Correlation Guide— New users o f th is te x t w ill a p p re c ia te th is resource. The g u ide
provides a sm ooth tra n s itio n fo r in s tru c to rs not c u rre n tly u sing th e Q engel/B oles text.
■ Image Library— The e le c tro n ic version o f th e fig u re s are s u p p lie d fo r easy in te g ra tio n in to
course p re se n ta tion s, exam s, and assignm ents.
■ Instructor's Guide— P rovides in s tru c to rs w ith h e lp fu l to o ls such as sam ple sy lla b i and
exam s, an A B E T conversion g u id e , a th e rm o d y n a m ic s glossary, and c h a p te r ob je ctive s.
■ Errata— If errors s h o u ld be fo u n d in th e s o lu tio n s m a nual, th e y w ill be reported here.
■ Solutions Manual— The d e ta ile d s o lu tio n s to all te x t hom ew ork pro b le m s are provided
in PDF fo rm .
■ EES Solutions Manual— The e n tire s o lu tio n s m anual is also a va ila b le in EES. Any problem
in th e te x t can be m o d ifie d and th e s o lu tio n of th e m o d ifie d problem can re a d ily be
o b ta in e d by c o p yin g and p a stin g th e given EES s o lu tio n on a b lank EES screen and
h ittin g th e solve b u tto n .
■ PP slides— P o w e rp oint p re se n ta tio n s lid e s fo r all ch a p te rs in th e te x t are a va ila b le fo r
use in lectures
■ Appendices— These are provided in PDF fo rm fo r ease o f use.


CHAPTER

I N T R O D U C T I O N AND
BASIC CONCEPTS

E

very science has a unique vocabulary associated with it, and thermody­
namics is no exception. Precise definition of basic concepts forms a

sound foundation for the development of a science and prevents possi­
ble misunderstandings. We start this chapter with an overview of thermody­
namics and the unit systems, and continue with a discussion of some basic
concepts such as system, state, state postulate, equilibrium, and process. We
also discuss temperature and temperature scales with particular emphasis on
the International Temperature Scale of 1990. We then present pressure, which
is the normal force exerted by a fluid per unit area and discuss absolute and
gage pressures, the variation of pressure with depth, and pressure measure­
ment devices, such as manometers and barometers. Careful study of these
concepts is essential for a good understanding of the topics in the following
chapters. Finally, we present an intuitive systematic problem-solving tech­
nique that can be used as a model in solving engineering problems.

1

Objectives
The objectives of Chapter 1 are to:
■

Identify the unique vocabulary
associated with thermodynamics
through the precise definition of
basic concepts to form a sound
foundation for the development
of the principles of
thermodynamics.

■

Review the metric SI and the

English unit systems th a t w ill be
used throughout the text.

■

Explain the basic concepts of
thermodynamics such as
system, state, state postulate,
equilibrium , process, and cycle.

■

Review concepts of temperature,
temperature scales, pressure,
and absolute and gage pressure.

■

Introduce an intuitive systematic
problem -solving technique.

1