Refrigeration Systems and Applications

Preface xvii

Acknowledgments xix

1 General Aspects of Thermodynamics 1

1.1 Introduction 1

1.2 Dimensions and Units 2

1.2.1 Systems of Units 2

1.2.1.1 Mass 2

1.2.1.2 Length 2

1.2.1.3 Force 3

1.2.1.4 Density and Specific Volume 3

1.2.1.5 Mass Flow Rate and Volumetric Flow Rate 3

1.2.1.6 Temperature 4

1.2.1.7 Pressure 6

1.3 Thermodynamics 9

1.3.1 Thermodynamic Systems 9

1.3.2 Thermodynamic Laws 10

1.3.3 First Law of Thermodynamics 10

1.3.4 Second Law of Thermodynamics 12

1.3.4.1 Exergy and its Importance 13

1.3.4.2 Reversibility and Irreversibility 15

1.3.4.3 Reversible Work and Exergy Destruction 15

1.3.5 Dincer's Six-step Approach 15

1.3.6 Pure Substances 25

1.3.6.1 State and Change of State 25

1.3.6.2 Vapor States 27

1.3.6.3 Sensible Heat, Latent Heat and Latent Heat of Fusion 27

1.3.6.4 Specific Heat 27

1.3.6.5 Specific Internal Energy 28

1.3.6.6 Specific Enthalpy 28

1.3.6.7 Specific Entropy 28

1.3.6.8 Energy Change and Energy Transfer 29

1.3.6.9 Flow Energy 29

1.3.6.10 Heat Transfer 29

1.3.6.11 Work 30

1.3.6.12 Thermodynamic Tables 30

1.4 Ideal and Real Gases 30

1.5 Refrigerators and Heat Pumps 36

1.5.1 The Carnot Refrigerators and Heat Pumps 38

1.6 Psychrometrics 49

1.6.1 Common Definitions in Psychrometrics 50

1.6.2 Balance Equations for Air and Water Vapor Mixtures 52

1.6.3 The Psychrometric Chart 53

1.7 Concluding Remarks 64

Nomenclature 64

Study Problems 67

References 70

2 Refrigerants 71

2.1 Introduction 71

2.2 Classification of Refrigerants 72

2.2.1 Halocarbons 72

2.2.2 Hydrocarbons 73

2.2.3 Inorganic Compounds 74

2.2.3.1 Ammonia (R-717) 74

2.2.3.2 Carbon dioxide (R-744) 75

2.2.3.3 Air (R-729) 75

2.2.4 Azeotropic mixtures 75

2.2.5 Nonazeotropic mixtures 76

2.3 Prefixes and Decoding of Refrigerants 76

2.3.1 Prefixes 76

2.3.2 Decoding the Number 77

2.3.3 Isomers 78

2.4 Secondary Refrigerants 79

2.5 Refrigerant-absorbent Combinations 80

2.6 Stratospheric Ozone Layer 82

2.6.1 Stratospheric Ozone Layer Depletion 84

2.6.2 Ozone Depletion Potential 85

2.6.3 Montreal Protocol 88

2.7 Global Warming 89

2.7.1 Global Warming Potential 93

2.8 Clean Air Act 94

2.8.1 Significant New Alternative Policies Program 94

2.8.2 Classification of Substances 96

2.9 Key Refrigerants 103

2.9.1 R-134a 103

2.9.2 R- 123 105

2.9.3 Nonazeotropic (Zeotropic) Mixtures 106

2.9.4 Azeotropic Mixtures 108

2.9.5 Ammonia (R-717) 110

2.9.6 Propane (R-290) 111

2.9.7 Carbon Dioxide (R-744) 113

2.10 Selection of Refrigerants 115

2.11 Thermophysical Properties of Refrigerants 116

2.12 Lubricating Oils and their Effects 120

2.13 Concluding Remarks 122

Study Problems 122

References 125

3 Refrigeration System Components 127

3.1 Introduction 127

3.2 History of Refrigeration 128

3.3 Main Refrigeration Systems 130

3.4 Refrigeration System Components 131

3.5 Compressors 132

3.5.1 Hermetic Compressors 133

3.5.2 Semi-hermetic Compressors 135

3.5.3 Open Compressors 136

3.5.4 Classification of Compressors 136

3.5.5 Positive Displacement Compressors 137

3.5.5.1 Reciprocating Compressors 137

3.5.5.2 Rotary Compressors 137

3.5.6 Dynamic Compressors 144

3.5.6.1 Centrifugal Compressors 144

3.5.6.2 Axial Compressors 147

3.5.7 Thermodynamic Analysis of Compressor 147

3.5.8 Compressor Capacity and Performance Assessment 149

3.5.8.1 Compression Ratio 149

3.5.8.2 Compressor Efficiency 150

3.5.8.3 Compressor Capacity Control for Better Performance 151

3.6 Condensers 156

3.6.1 Water-cooled Condensers 157

3.6.2 Air-cooled Condensers 157

3.6.3 Evaporative Condensers 158

3.6.4 Cooling Towers 159

3.6.5 Thermodynamic Analysis of Condenser 160

3.7 Evaporators 165

3.7.1 Liquid Coolers 165

3.7.2 Air and Gas Coolers 166

3.7.3 Thermodynamic Analysis of Evaporator 167

3.8 Throttling Devices 172

3.8.1 Thermostatic Expansion Valves 172

3.8.2 Constant Pressure Expansion Valves 173

3.8.3 Float Valves 173

3.8.4 Capillary Tubes 174

3.8.5 Thermodynamic Analysis of Throttling Valve 174

3.9 Auxiliary Devices 177

3.9.1 Accumulators 177

3.9.2 Receivers 178

3.9.3 Oil Separators 178

3.9.4 Strainers 179

3.9.5 Dryers 179

3.9.6 Check Valves 179

3.9.7 Solenoid Valves 179

3.9.8 Defrost Controllers 179

3.10 Concluding Remarks 180

Nomenclature 180

Study Problems 182

References 187

4 Refrigeration Cycles and Systems 189

4.1 Introduction 189

4.2 Vapor-compression Refrigeration Systems 189

4.2.1 Evaporation 190

4.2.2 Compression 190

4.2.3 Condensation 190

4.2.4 Expansion 191

4.3 Energy Analysis of Vapor-compression Refrigeration Cycle 192

4.4 Exergy Analysis of Vapor-compression Refrigeration Cycle 195

4.5 Actual Vapor-compression Refrigeration Cycle 200

4.5.1 Superheating and Subcooling 201

4.5.1.1 Superheating 201

4.5.1.2 Subcooling 203

4.5.2 Defrosting 204

4.5.3 Purging Air in Refrigeration Systems 205

4.5.3.1 Air Purging Methods 206

4.5.4 Twin Refrigeration System 209

4.6 Air-standard Refrigeration Systems 210

4.6.1 Energy and Exergy Analyses of a Basic Air-standard Refrigeration Cycle 211

4.7 Absorption Refrigeration Systems 216

4.7.1 Basic Absorption Refrigeration Systems 218

4.7.2 Ammonia-water (NH₃-H₂O) Absorption Refrigeration Systems 219

4.7.3 Energy Analysis of an Absorption Refrigeration System 221

4.7.4 Three-fluid (Gas Diffusion) Absorption Refrigeration Systems 224

4.7.5 Water-lithium Bromide (H₂O -LiBr) Absorption Refrigeration Systems 225

4.7.5.1 Single-effect Absorption Refrigeration Systems 226

4.7.5.2 Double-effect Absorption Refrigeration Systems 227

4.7.5.3 Crystallization 229

4.7.6 Steam Ejector Recompression Absorption Refrigeration Systems 230

4.7.7 Electrochemical Absorption Refrigeration Systems 231

4.7.8 Absorption-augmented Refrigeration System 232

4.7.9 Exergy Analysis of an Absorption Refrigeration System 239

4.7.10 Performance Evaluation of an Absorption Refrigeration System 243

4.8 Concluding Remarks 245

Nomenclature 245

Study Problems 247

References 258

5 Advanced Refrigeration Cycles and Systems 261

5.1 Introduction 261

5.2 Multistage Refrigeration Cycles 262

5.3 Cascade Refrigeration Systems 268

5.3.1 Two-stage Cascade Systems 269

5.3.2 Three-stage (Ternary) Cascade Refrigeration System 274

5.4 Multi-effect Absorption Refrigeration Systems 280

5.5 Steam-jet Refrigeration Systems 311

5.6 Adsorption Refrigeration 317

5.7 Stirling Cycle Refrigeration 322

5.7.1 Performance Assessment 325

5.8 Thermoelectric Refrigeration 328

5.8.1 Performance Assessment of Thermoelectric Coolers 329

5.9 Thermoacoustic Refrigeration 332

5.10 Metal Hydride Refrigeration 334

5.10.1 Operational Principles 335

5.10.2 Regeneration Process 336

5.10.3 Refrigeration Process 336

5.11 Magnetic Refrigeration 337

5.11.1 Magnetic Refrigeration Cycle 339

5.11.2 Active Magnetic Regenerators 340

5.12 Supermarket Refrigeration Practices 345

5.12.1 Direct Expansion Systems 346

5.12.2 Distributed Systems 347

5.12.3 Secondary Loop Systems 348

5.13 Concluding Remarks 349

Nomenclature 349

Study Problems 351

References 354

6 Renewable Energy-based Integrated Refrigeration Systems 357

6.1 Introduction 357

6.2 Solar-powered Absorption Refrigeration Systems 358

6.3 Solar-powered Vapor-compression Refrigeration Systems 364

6.4 Wind-powered Vapor-compression Refrigeration Systems 368

6.5 Hydropowered Vapor-compression Refrigeration Systems 371

6.6 Geothermal-powered Vapor-compression Refrigeration Systems 375

6.7 Ocean Thermal Energy Conversion Powered Vapor-compression Refrigeration Systems 379

6.8 Biomass-powered Absorption Refrigeration Systems 383

6.9 Concluding Remarks 393

Nomenclature 394

Study Problems 395

Reference 398

7 Heat Pipes 399

7.1 Introduction 399

7.2 Heat Pipes 400

7.2.1 Heat Pipe Use 403

7.3 Heat Pipe Applications 403

7.3.1 Heat Pipe Coolers 404

7.3.2 Insulated Water Coolers 404

7.3.3 Heat Exchanger Coolers 404

7.4 Heat Pipes for Electronics Cooling 405

7.5 Types of Heat Pipes 407

7.5.1 Micro Heat Pipes 408

7.5.2 Cryogenic Heat Pipes 408

7.6 Heat Pipe Components 408

7.6.1 Container 410

7.6.2 Working Fluid 411

7.6.3 Selection of Working Fluid 413

7.6.4 Wick or Capillary Structure 414

7.7 Operational Principles of Heat Pipes 417

7.7.1 Heat Pipe Operating Predictions 418

7.7.1.1 Gravity-aided Orientation 419

7.7.1.2 Horizontal Orientation 419

7.7.1.3 Against Gravity Orientation 420

7.7.2 Heat Pipe Arrangement 421

7.8 Heat Pipe Performance 421

7.8.1 Effective Heat Pipe Thermal Resistance 423

7.9 Design and Manufacture of Heat Pipes 424

7.9.1 Thermal Conductivity of a Heat Pipe 427

7.9.2 Common Heat Pipe Diameters and Lengths 427

7.10 Heat-transfer Limitations 428

7.11 Heat Pipes in Heating, Ventilating and Air Conditioning 429

7.11.1 Dehumidifier Heat Pipes 430

7.11.1.1 Working Principle 431

7.11.1.2 Indoor Dehumidifier Heat Pipes 432

7.11.2 Energy Recovery Heat Pipes 433

7.12 Concluding Remarks 436

Nomenclature 436

Study Problems 437

References 439

8 Food Refrigeration 441

8.1 Introduction 441

8.2 Food Deterioration 442

8.3 Food Preservation 443

8.4 Food Quality 444

8.5 Food Precooling and Cooling 446

8.6 Food Precooling Systems 448

8.6.1 Energy Coefficient 449

8.6.2 Hydrocooling 450

8.6.2.1 Hydrocooling using Ice or Ice-slush Cooling 453

8.6.2.2 Hydrocooling using Artificial Ice 453

8.6.2.3 Hydrocooling using Natural Ice 454

8.6.2.4 Hydrocooling using Natural Snow 455

8.6.2.5 Hydrocooling using Compacted Snow 455

8.6.3 Forced-air Cooling 456

8.6.3.1 Methods of Forced-air Cooling 459

8.6.3.2 Cold-wall-type Tunnel Forced-air Cooling 461

8.6.3.3 Serpentine Cooling 463

8.6.3.4 Single-pallet Forced-air Cooling 464

8.6.3.5 Room Cooling (with Storage and Shipping) 464

8.6.3.6 Ice-bank Forced-air Cooling System 464

8.6.3.7 Forced-air Cooling with Winter Coldness 465

8.6.3.8 Technical Details of Forced-air Cooling Systems 466

8.6.3.9 Engineering/economic Model for Forced-air Cooling Systems 468

8.6.4 Hydraircooling 469

8.6.5 Vacuum Cooling 471

8.6.6 Hydrovac Cooling 475

8.6.7 Evaporative Cooling 475

8.6.8 Ice Cooling 476

8.7 Precooling of Milk 477

8.8 Food Freezing 479

8.9 Cool and Cold Storage 480

8.9.1 Chilling Injury 481

8.9.2 Optimum Storage Conditions 481

8.9.2.1 Optimum Temperature 481

8.9.2.2 Optimum Relative Humidity 482

8.9.3 Technical Aspects of Cold Stores 485

8.9.3.1 Shape and Size 486

8.9.3.2 Construction Methods 486

8.9.3.3 Insulation 487

8.9.3.4 Vapor Barriers 488

8.9.3.5 Floors 488

8.9.3.6 Cold-air Distribution 488

8.9.3.7 Defrosting 489

8.9.3.8 Cold Store Planning 489

8.9.3.9 Refrigeration 490

8.9.4 Calculation of Cold Store Refrigeration Loads 490

8.9.5 Energy-efficient Cold Store 492

8.9.6 Photovoltaic-powered Cold Store 493

8.10 Controlled Atmosphere Storage 496

8.10.1 Controlled Atmosphere Storage Ripening and Waxing 500

8.10.2 Container-controlled Atmospheres 501

8.10.2.1 Controlled Modified Atmosphere Systems 501

8.10.2.2 Modified Atmospheres in Containers 502

8.10.2.3 Modified Atmospheres in Packaging 502

8.10.2.4 Pressure Swing Absorption Systems 502

8.10.2.5 Membrane Separation Systems 502

8.10.3 Packaging 503

8.10.4 Definitions 503

8.10.5 Modified Atmosphere Packaging 503

8.10.6 Modified Atmosphere Cooling 505

8.11 Refrigerated Transport 506

8.11.1 Reefer Technology 507

8.11.1.1 Controlled-atmosphere Reefer Containers 507

8.11.2 Quality Aspects of Products 507

8.11.3 Effective Packaging for Quality 508

8.11.4 Transport Storage 509

8.11.5 Temperature Control 511

8.11.5.1 Temperature Control and Monitoring 512

8.11.5.2 Temperature Monitoring Systems 513

8.11.6 Transportation Aspects 513

8.11.7 Recommended Transit and Storage Procedures 514

8.11.8 Developments in Refrigerated Transport 514

8.11.8.1 Sea and Land Transport 515

8.11.8.2 Air Transport 515

8.12 Respiration (Heat Generation) 515

8.12.1 Measurement of Respiratory Heat Generation 516

8.13 Transpiration (Moisture Loss) 516

8.13.1 Shrinkage 521

8.14 Cooling Process Parameters 522

8.14.1 Cooling Coefficient 522

8.14.2 Lag Factor 523

8.14.3 Half Cooling Time 523

8.14.4 Seven-eighths Cooling Time 523

8.15 Analysis of Cooling Process Parameters 524

8.15.1 Lin et al.'s Model for Irregular Shapes 527

8.16 Fourier-Reynolds Correlations 529

8.16.1 Development of Fourier-Reynolds Correlations 530

8.17 Cooling Heat-transfer Parameters 533

8.17.1 Specific Heat 533

8.17.1.1 Some Correlations for Specific Heat 534

8.17.2 Thermal Conductivity 535

8.17.2.1 Some Correlations for Thermal Conductivity 536

8.17.3 Thermal Diffusivity 538

8.17.4 Effective Heat-transfer Coefficients 540

8.17.4.1 Smith et al.'s Model 543

8.17.4.2 Ansari's Model 544

8.17.4.3 Stewart et al.'s Model 544

8.17.4.4 Dincer and Dost's Models 545

8.17.4.5 Some Methods for Effective Heat-transfer Coefficients 546

8.17.5 Modeling for Thermal Diffusivity and Heat-transfer Coefficient 547

8.17.6 Effective Nusselt-Reynolds Correlations 555

8.17.7 The Dincer Number 557

8.18 Conclusions 560

Nomenclature 561

Study Problems 563

References 565

9 Food Freezing 573

9.1 Introduction 573

9.2 Food Freezing Aspects 574

9.2.1 Enzymatic Reactions 575

9.2.2 Microbiological Activities 576

9.3 Quick Freezing 577

9.4 Enthalpy 577

9.5 Crystallization 578

9.6 Moisture Migration 579

9.7 Weight Loss 579

9.8 Blanching 580

9.9 Packaging 582

9.10 Quality of Frozen Foods 582

9.10.1 Objective Tests 583

9.10.2 Sensory Tests 583

9.10.3 Tests on the Kinetics of Quality Loss 583

9.11 Food Freezing Process 585

9.11.1 Freezing of Fruits 586

9.11.2 Freezing of Vegetables 586

9.12 Freezing Point 588

9.13 Freezing Rate 589

9.14 Freezing Times 590

9.14.1 Plank's Model 592

9.14.2 Mellor's Model 592

9.14.3 Pham's Model 593

9.14.4 Cleland and Earle's Model 594

9.14.5 Mannapperuma et al.'s Model 595

9.15 Freezing Equipment 598

9.15.1 Tunnel Freezers 599

9.15.1.1 Packaged Tunnel Freezers 600

9.15.1.2 Modular Tunnel Freezers 601

9.15.1.3 Multipass Tunnel Freezers 602

9.15.1.4 Contact Belt Tunnel Freezers 603

9.15.1.5 Drag Thru Doly Freezers 603

9.15.2 Spiral Freezers 604

9.15.2.1 Packaged Spiral Freezers 605

9.15.2.2 Site-built Spiral Freezers 606

9.15.3 Plate (Tray) Freezers 606

9.15.3.1 Packaged Tray Freezers 608

9.15.4 Impingement Jet Freezers 608

9.15.5 Cryogenic Freezers 609

9.15.5.1 Immersing Cryogenic Freezers 611

9.15.5.2 Tunnel Cryogenic Freezers 612

9.15.6 Control in Freezers 612

9.16 Ice Making 613

9.16.1 Block Ice Manufacture 613

9.16.2 Shell Ice Manufacture 614

9.16.3 Flake Ice Manufacture 614

9.16.4 Tube Ice Manufacture 614

9.16.5 Plate Ice Manufacture 615

9.16.6 Slush, Slurry or Binary Ice Manufacture 615

9.17 Thawing 615

9.18 Freeze-drying 616

9.18.1 Operation Principles 617

9.18.2 Freeze-drying Times 619

9.18.3 Freeze-dryers 621

9.18.3.1 Batch-type Freeze-dryers 622

9.18.3.2 Continuous-type Freeze-dryers 624

9.18.3.3 Microwave and Dielectric Freeze-dryers 625

9.18.4 Atmospheric Freeze-drying 625

9.19 Conclusions 625

Nomenclature 626

Study Problems 627

References 628

10 Environmental Impact and Sustainability Assessment of Refrigeration Systems 631

10.1 Introduction 631

10.2 Environmental Concerns 633

10.3 Energy and Environmental Impact 637

10.4 Dincer's Six Pillars 638

10.5 Dincer's 3S Concept 638

10.6 System Greenization 639

10.7 Sustainability 641

10.8 Energy and Sustainability 643

10.9 Exergy and Sustainability 645

10.10 Concluding Remarks 667

Study Problems 668

References 668

Appendix A Conversion Factors 671

Appendix B Thermophysical Properties 675

Appendix C Food Refrigeration Data 701

Index 719