Pumps as Turbines (eBook)

Preface 6
Acknowledgements 8
Contents 9
Theoretical Aspects 16
1 Introduction 17
Abstract 17
1.1 Micro/Pico Hydroelectric Power Stations 18
1.2 Micro/Pico Hydraulic Turbines 20
1.2.1 The Pelton/Turgo Turbine 20
1.2.2 The Cross Flow Turbine 22
1.2.3 The Propeller Turbine 23
1.2.4 The Pump as Turbine (PAT) 23
1.3 Field of PAT Application 27
1.3.1 Introduction 27
1.3.2 Natural Streams 28
1.3.3 Water Supply 30
1.3.4 Other Users 33
References 39
2 Reverse Pump Theory 41
Abstract 41
2.1 PAT Components 42
2.1.1 The Volute 42
2.1.2 The Impeller 43
2.1.3 The Draft Tube 44
2.2 PAT Theory 44
2.3 Flow Pattern in a Pump and in a PAT 47
2.4 Application of Computational Fluid Dynamics (CFD) to a PAT 50
2.4.1 Importance of CFD 50
2.4.2 Mathematical Approach 51
2.4.3 PAT Geometry Modeling and Mesh Generation 52
2.4.4 CFD Solutions for a PAT 56
2.5 Cavitation in a PAT 59
2.6 Pressure Surge Analysis in a PAT 62
References 70
3 Industrial Aspects of PAT Design Improvement 72
Abstract 72
3.1 Impeller Refinement 73
3.1.1 Rounding of the Blade’s Leading Edge and the Hub/Shroud Inlet Edges of a PAT 73
3.1.2 Impeller Diameter (Trimming Effect) 75
3.2 Inlet/Outlet Part Refinement 75
3.3 PAT Reliability 78
3.4 PAT Life Cycle 83
References 85
PAT Based Micro/Pico Hydropower Stations 87
4 PAT Selection 88
Abstract 88
4.1 Theoretical and Practical Methods 88
4.2 Estimation of Characteristic Curves 94
4.3 Rotational Speed Selection 98
4.4 Impeller Diameter Selection 99
4.5 PATs in Parallel 99
4.6 PAT-Pump Direct Coupling 101
References 106
5 PAT Control Systems 108
Abstract 108
5.1 Operating Conditions in a WSN 109
5.2 PAT Working Conditions 114
5.2.1 The HR Mode 115
5.2.2 The ER Mode 115
5.2.3 The HER Mode 116
5.2.4 The SSP Mode 117
5.3 Plant Effectiveness 119
5.3.1 System Capability 119
5.3.2 System Reliability 120
5.3.3 System Flexibility 121
5.3.4 System Sustainability 121
5.4 PAT Selection 122
References 127
6 Civil Engineering Design, Electromechanics, Installation and Operation 128
Abstract 128
6.1 Civil Engineering Design 128
6.1.1 Intake and Turbine Inlet 129
6.1.2 The Powerhouse 132
6.1.3 Turbine Outlet 134
6.2 Mechanical Components 134
6.2.1 The Shaft 136
6.2.2 The Shaft Seal 136
6.2.3 The Bearing 137
6.2.4 The Coupling 138
6.3 Electrical components 138
6.4 Installation Procedure 144
6.5 Operation and Maintenance 146
References 147
Applications and Impacts 148
7 Location of a PAT in a Water Transmission and Distribution System 149
Abstract 149
7.1 Selecting the Site 150
7.2 Flow Rate and Head Measurement 152
7.3 Pressure Control in Water Transmission Systems 157
7.4 Identification of Dissipation Points 158
7.5 Dynamic Control of Pressure 162
7.6 Numerical Methods 164
7.6.1 Hydraulic Modelling 164
7.6.2 Control Valves 166
7.6.3 Runaway Conditions 169
7.7 Pressure Surge Control 171
7.7.1 Basic Considerations 171
7.7.2 PAT Shutdowns with Control Valve Closure 177
7.7.3 PAT Start-Up and Control Valve Opening 178
7.7.4 Overspeed Effect in a PAT 178
References 179
8 PAT System Economic Analysis 182
Abstract 182
8.1 Fundaments 183
8.2 Time Value of Money 185
8.3 Methods of Economic Evaluation 187
8.3.1 Net Present Value (NPV) 188
8.3.2 Benefit/Cost Ratio (B/C) 188
8.3.3 Internal Rate of Return (IRR) 188
8.3.4 Payback Period (T) 189
8.3.5 Economic Feasibility 189
8.4 Effects of the Lifetime Cycle 190
References 195
9 Application of PAT Technology 197
Abstract 197
9.1 Working Plants 198
9.1.1 Malecòn, Spain 198
9.1.2 San Vito di Cadore, Italy 202
9.1.3 Capodacqua, Italy 205
9.1.4 Conejeras and Cartuja, Spain 207
9.1.5 San Antonio, Chile 208
9.1.6 Beliche, Portugal 210
9.2 Pilot Plants 212
9.2.1 Naples, Italy, Pilot Plant 212
9.2.2 Lisbon, Portugal, Pilot Plant 216
References 225