Preface ...................................................... xiii
Acknowledgments .............................................. xvii
Author ........................................................ xix
1 Introduction ............................................... 1
1.1 Thermal Energy Systems Design and Analysis ................. 1
1.2 Software ................................................... 2
1.3 Thermal Energy System Topics ............................... 3
1.4 Units and Unit Systems ..................................... 3
1.5 Thermophysical Properties .................................. 6
1.5.1 Viscosity ........................................... 7
1.5.1.1 Dynamic Viscosity ............................... 7
1.5.1.2 Kinematic Viscosity ............................. 8
1.5.1.3 Newtonian and Non-Newtonian Fluids .............. 9
1.6 Engineering Design ........................................ 13
1.6.1 Engineering Design and Ethics ...................... 14
Problems .................................................. 15
2 Engineering Economics ..................................... 17
2.1 Introduction .............................................. 17
2.2 Common Engineering Economics Nomenclature ................. 17
2.3 Economic Analysis Tool: The Cash Flow Diagram ............. 18
2.4 Time Value of Money ....................................... 19
2.4.1 Finding the Future Value of a Present Sum:
The Single Payment Compound Amount Factor .......... 20
2.4.2 Finding the Present Value of a Future Sum: The
Present Worth Factor ............................... 22
2.4.3 Nominal and Effective Interest Rates ............... 22
2.4.4 Finding the Future Value of a Uniform Series: The
Compound Amount Factor ............................. 22
2.4.5 Finding the Equivalent Uniform Series That
Represents a Future Value: The Uniform Series
Sinking Fund Factor ................................ 24
2.4.6 Finding the Present Value of a Uniform Series:
The Uniform Series Present Worth Factor ............ 24
2.4.7 Finding the Uniform Series That Is Equivalent to
a Present Value: The Capital Recovery Factor ....... 25
2.4.8 Finding the Present Value of a Uniform Linearly
Increasing Series: The Gradient Present Worth
Factor ............................................. 25
2.4.9 Summary of Interest Factors ........................ 27
2.5 Time Value of Money Examples .............................. 27
2.6 Using Software to Calculate Interest Factors .............. 32
2.7 Economic Decision Making .................................. 34
2.7.1 Present Worth Method ............................... 34
2.7.2 Annual Cost Method ................................. 35
2.7.3 Selection of Alternatives .......................... 38
2.8 Depreciation and Taxes .................................... 38
2.8.1 After-Tax Cash Flow ................................ 38
2.8.2 Straight Line Depreciation ......................... 39
2.8.3 Sum of the Years' Digits ........................... 39
Problems .................................................. 44
3 Analysis of Thermal Energy Systems ........................ 49
3.1 Introduction .............................................. 49
3.2 Nomenclature .............................................. 49
3.3 Thermophysical Properties of Substances ................... 50
3.3.1 Thermodynamic Properties in the Two-Phase Region ... 51
3.3.2 Important Thermodynamic Properties and
Relationships ...................................... 52
3.3.3 Evaluation of Thermodynamic Properties ............. 53
3.3.3.1 Real Fluid Model ............................... 53
3.3.3.2 Incompressible Substance Model ................. 54
3.3.3.3 Ideal Gas Model ................................ 59
3.4 Suggested Thermal Energy Systems Analysis Procedure ....... 65
3.5 Conserved and Balanced Quantities ......................... 66
3.5.1 Generalized Balance Law ............................ 66
3.6 Conservation of Mass ...................................... 67
3.7 Conservation of Energy (The First Law of Thermodynamics) .. 72
3.8 Entropy Balance (The Second Law of Thermodynamics) ........ 80
3.8.1 Reversible and Adiabatic Process ................... 83
3.8.2 Isentropic Efficiencies of Flow Devices ............ 83
3.8.2.1 Turbines ....................................... 83
3.8.2.2 Compressors, Pumps, and Fans ................... 85
3.8.2.3 Nozzles ........................................ 86
3.8.2.4 Diffusers ...................................... 86
3.9 Exergy Balance: The Combined Law .......................... 90
3.9.1 What Is Exergy? .................................... 90
3.9.1.1 Definition of Exergy ........................... 92
3.9.2 Exergy Balance ..................................... 92
3.9.3 Exergy Accounting and Exergy Flow Diagrams ......... 96
3.9.4 Exergetic Efficiencies of Flow Devices ............. 97
3.9.4.1 Turbines ....................................... 97
3.9.4.2 Compressors, Pumps, and Fans ................... 97
3.9.4.3 Heat Exchangers ................................ 98
3.10 Energy and Exergy Analysis of Thermal Energy Cycles ...... 100
3.10.1 Cycle Energy Performance Parameters ............... 101
3.10.1.1 Maximum Thermal Efficiency of a Cycle ......... 104
3.10.2 Exergetic Cycle Efficiency ........................ 107
3.10.2.1 Power Cycles .................................. 107
3.10.2.2 Refrigeration and Heat Pump Cycles ............ 108
3.10.2.3 Significance of the Exergetic Cycle
Efficiency .................................... 110
3.10.2.4 Energy/Exergy Conundrum ....................... 111
3.11 Detailed Analysis of Thermal Energy Cycles ............... 113
3.11.1 Solution Strategy for Cycle Analysis .............. 113
3.11.2 Thermal Energy Cycle Examples ..................... 116
Problems ................................................. 130
4 Fluid Transport in Thermal Energy Systems ................ 137
4.1 Introduction ............................................. 137
4.2 Piping and Tubing Standards .............................. 137
4.3 Fluid Flow Fundamentals .................................. 139
4.3.1 Head Loss due to Friction in Pipes and Tubes ...... 142
4.4 Valves and Fittings ...................................... 155
4.4.1 Valves ............................................ 156
4.4.1.1 Check Valves .................................. 159
4.4.1.2 Control Valves ................................ 162
4.4.2 Fittings .......................................... 162
4.4.2.1 Loss Coefficients for Tees and Wyes ........... 163
4.5 Design and Analysis of Pipe Networks ..................... 167
4.6 Economic Pipe Diameter ................................... 177
4.6.1 Cost of a Pipe System ............................. 177
4.6.2 Determination of the Economic Diameter ............ 178
4.6.3 Cost Curves ....................................... 186
4.6.4 Estimated Economic Velocities ..................... 188
4.7 Pumps .................................................... 190
4.7.1 Types of Pumps .................................... 191
4.7.2 Dynamic Pump Operation ............................ 191
4.7.2.1 Dynamic Pump Performance ...................... 193
4.7.3 Manufacturer's Pump Curves ........................ 196
4.7.4 System Curve ...................................... 197
4.7.4.1 System Curve for a Two-Tank System Open to
the Atmosphere ................................ 198
4.7.4.2 System Curve for a Closed-Loop System ......... 199
4.7.5 Pump Selection .................................... 201
4.7.6 Cavitation and the Net Positive Suction Head ...... 208
4.7.6.1 Calculating the NPSHA ......................... 209
4.7.7 Series and Parallel Pump Configurations ........... 214
4.7.8 Affinity Laws ..................................... 218
4.8 Design Practices for Pump/Pipe Systems ................... 222
4.8.1 Economics ......................................... 223
4.8.2 Environmental Impact .............................. 223
4.8.3 Noise and Vibration ............................... 224
4.8.4 Pump Placement and Flow Control ................... 224
4.8.5 Valves ............................................ 225
4.8.6 Expansion Tanks and Entrained Gases ............... 225
4.8.7 Other Sources for Design Practices ................ 225
Problems ................................................. 226
5 Energy Transport in Thermal Energy Systems ............... 237
5.1 Introduction ............................................. 237
5.2 Review of Heat Transfer Mechanisms in Heat Exchangers .... 237
5.2.1 Thermal Resistance ................................ 239
5.2.2 Heat Transfer Augmentation with Fins .............. 243
5.2.3 Convective Heat Transfer Coefficient .............. 248
5.2.3.1 Forced External Cross Flow over a Cylindrical
Surface ....................................... 250
5.2.3.2 Laminar Flow Inside Circular Pipes or Tubes ... 250
5.2.3.3 Turbulent Flow Inside a Circular Tube ......... 252
5.2.4 Fouling on Heat Exchange Surfaces ................. 253
5.2.5 Overall Heat Transfer Coefficient ................. 254
5.3 Heat Exchanger Types ..................................... 259
5.3.1 Double-Pipe Heat Exchanger ........................ 259
5.3.2 Shell and Tube Heat Exchanger ..................... 260
5.3.3 Plate and Frame Heat Exchanger .................... 261
5.3.4 Cross-Flow Heat Exchanger ......................... 261
5.4 Design and Analysis of Heat Exchangers ................... 263
5.4.1 Heat Exchanger Design Problem ..................... 263
5.4.2 Heat Exchanger Analysis Problem ................... 265
5.4.3 Logarithmic Mean Temperature Difference ........... 265
5.4.4 LMTD Heat Exchanger Model ......................... 272
5.4.5 Effectiveness-NTU (e-NTU) Heat Exchanger Model .... 275
5.5 Special Application Heat Exchangers ...................... 284
5.5.1 Counterflow Regenerative Heat Exchanger ........... 284
5.5.2 Heat Exchangers with Phase Change Fluids:
Boilers, Evaporators, and Condensers .............. 287
5.6 Double-Pipe Heat Exchanger Design and Analysis ........... 293
5.6.1 Double-Pipe Heat Exchanger Diameters .............. 293
5.6.2 Overall Heat Transfer Coefficients for the
Double-Pipe Heat Exchanger ........................ 294
5.6.3 Hydraulic Analysis of the Double-Pipe Heat
Exchanger ......................................... 295
5.6.4 Fluid Placement in a Double-Pipe Heat Exchanger ... 296
5.6.5 Double-Pipe Heat Exchanger Design Considerations .. 297
5.6.6 Use of Computer Software for Design and Analysis
of Heat Exchangers ................................ 298
5.6.7 Double-Pipe Heat Exchanger Design Example ......... 298
5.6.7.1 Fluid Properties .............................. 298
5.6.7.2 Fluid Placement ............................... 299
5.6.7.3 Determination of Tube Sizes ................... 299
5.6.7.4 Calculation of Annulus Diameters .............. 301
5.6.7.5 Calculation of the Reynolds Numbers ........... 301
5.6.7.6 Calculation of the Friction Factors ........... 302
5.6.7.7 Calculation of Nusselt Numbers ................ 302
5.6.7.8 Calculation of the Convective Heat Transfer
Coefficients .................................. 302
5.6.7.9 Calculation of the Overall Heat Transfer
Coefficients .................................. 302
5.6.7.10 Application of the Heat Exchanger Model ....... 303
5.6.7.11 Calculation of the Pressure Drops through
the Heat Exchanger ............................ 305
5.6.7.12 Summary of the Final Design ................... 305
5.6.8 Double-Pipe Heat Exchanger Analysis Example ....... 305
5.7 Shell and Tube Heat Exchanger Design and Analysis ........ 311
5.7.1 LMTD for Shell and Tube Heat Exchangers ........... 315
5.7.2 Tube-Side Analysis of Shell and Tube Heat
Exchangers ........................................ 316
5.7.3 Shell-Side Analysis of Shell and Tube Heat
Exchangers ........................................ 317
5.7.4 Shell and Tube Heat Exchanger Design
Considerations .................................... 319
5.7.4.1 Tube-Side Considerations ...................... 319
5.7.4.2 Shell-Side Considerations ..................... 320
5.7.4.3 General Considerations ........................ 320
5.7.5 Shell and Tube Heat Exchanger Design and
Analysis Example .................................. 320
5.7.5.1 Fluid Properties .............................. 321
5.7.5.2 Heat Exchanger Parameters ..................... 321
5.7.5.3 Calculation of Characteristic Flow Areas
and Velocities ................................ 321
5.7.5.4 Calculation of the Reynolds Numbers ........... 323
5.7.5.5 Calculation of the Friction Factors ........... 323
5.7.5.6 Calculation of the Nusselt Numbers ............ 323
5.7.5.7 Calculation of the Convective Heat Transfer
Coefficients .................................. 323
5.7.5.8 Calculation of the Overall Heat Transfer
Coefficients .................................. 324
5.7.5.9 Application of the Heat Exchanger Model ....... 324
5.7.5.10 Calculation of the Pressure Drops ............. 326
5.8 Plate and Frame Heat Exchanger Design and Analysis ....... 328
5.8.1 Plate and Frame Heat Exchanger Model .............. 334
5.8.2 Plate and Frame Heat Exchanger Design and
Analysis Example .................................. 334
5.9 Cross-Flow Heat Exchanger Design and Analysis ............ 339
Problems ................................................. 344
6 Simulation, Evaluation, and Optimization of
Thermal Energy Systems ................................... 355
6.1 Introduction ............................................. 355
6.2 Thermal Energy System Simulation ......................... 356
6.2.1 Pump and Pipe System Simulation ................... 356
6.2.2 Modeling Thermal Equipment ........................ 361
6.2.2.1 Exact-Fitting Method .......................... 363
6.2.2.2 Method of Least Squares ....................... 368
6.2.3 Simulation Example: Simulation of an Air
Conditioning System ............................... 374
6.2.4 Advantages and Pitfalls of Thermal Energy System
Simulation ........................................ 377
6.3 Thermal Energy System Evaluation ......................... 378
6.4 Thermal Energy System Optimization ....................... 381
6.4.1 Mathematical Statement of Optimization ............ 381
6.4.2 Closed-Form Solution of the Optimization Problem .. 383
6.4.3 Method of Lagrange Multipliers .................... 384
6.4.4 Formulation and Solution of Optimization
Problems Using Software ........................... 390
6.4.5 Final Comments Regarding Thermal Energy System
Optimization ...................................... 393
Problems ................................................. 394
Appendix A: Conversion Factors ................................ 403
Appendix B: Thermophysical Properties ......................... 413
Appendix C: Standard Pipe Dimensions .......................... 461
Appendix D: Standard Copper Tubing Dimensions ................. 471
Appendix E: Resistance Coefficients for Valves and Fittings ... 475
Appendix F: Optimization Using Engineering Equation Solver .... 481
Appendix G: Pump Curves ....................................... 487
References .................................................... 545
Index ......................................................... 547
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