Geothermal HVAC. Modern. Engineering and Control Applications. Greg Cunniff. Jay Egg. Carl D. Orio. Mc Graw Hill Education

Transcription

1 Modern Geothermal HVAC Engineering and Control Applications Jay Egg Greg Cunniff Carl D. Orio Mc Graw Hill Education New York Chicago San Francisco Lisbon London Madrid Mexico City Milan New Delhi San Juan Seoul Singapore Sydney Toronto

2 Contents Preface Acknowledgments xi xiii 1 Low-Temperature Geothermal or Earth Coupling 1 Longevity versus Energy Savings 4 Engineered Failure 7 Comfort Level 8 Water to Water 9 Hydronic Heating and Cooling 9 Pool Heating 10 Understanding the Geothermal Heat-Pump Concept 10 General Methods of Earth Coupling 13 Applications of the Various Types of Earth Coupling 14 Summary from David Hoffman, PE 18 Pump Sizing 18 Pump Operation 19 Hydronic Specialties 19 Water-to-Water Heat Pumps 20 Desuperheaters 21 Commissioning 21 Miscellaneous Efficiency Items 22 Review Questions 22 2 Geothermal Heat-Pump Equipment 25 Cabinet Construction 25 Sound Levels 25 Compressor 26 Fan Type 26 Drain-Pan Construction 27 Valve Options 27 Domestic Hot-Water Options 27 Integrated Pump Kits 27 Flow Restrictors 28 Solenoid and Proportional Valves 29 Some Other Specialties 29 Superefficient DC Systems 31 Equipment Orientation 33 Direct-Expansion Geothermal Heat Pump 34 Commercial Chillers, Geothermal-Sourced 36 Variable-Refrigerant-Volume Systems 37 V

3 vi Contents Summary 39 Review Questions 41 3 Variations in Earth Coupling 43 Efficiency 47 First Cost 49 Geology 49 Maintenance 50 Regulatory Requirements 51 Thermal Stability 51 Designing Geothermal Heat-Pump Systems 52 Lessons Learned from Geothermal Projects 53 Lend Lease 57 New Hampshire Nursing Home 60 Smart Controls 61 Outside the Heat-Pump Box 62 Specify the Best, and Let the Customer Decide 79 Do Geothermal Systems Wear Out? 85 Hydronic Geothermal? 90 Agricultural Geothermal Applications 92 Animals 92 Fruits and Vegetables 93 Dual-Purpose Wells: Geothermal and Domestic 93 The Riversdale Museum Standing-Column Well Installation 94 YWCA in Canton, Ohio, Switches Over from Closed Loop to Open Loop by Yoder Geothermal 96 Review Questions Application of Earth Coupling with Regard to Site Conditions Closed-Loop Ground-Coupled Systems 105 Surface-Water Closed-Coupled Systems 105 Pump and Reinjection Earth-Coupled Systems 107 Direct-Expansion Geothermal Systems 107 Types of Earth and Related Conductivity 109 Designing the Closed-Loop Heat Exchanger Open Fields/Schools Under Parking Lots Under Buildings Front or Back Yards Rights-of-Way and Under Streets Common Areas/Golf Courses/Parks 114 Bid Specifications for Drilling 115 Cooling Towers 115 More on Geothermal versus Evaporative Cooling Towers 123 Geothermal Case Studies 126 Remediation of Failed Geothermal Systems 126 Direct-Expansion Geothermal HVAC Systems 127 Review Questions 131

4 Contents vii 5 Closed-Loop Earth Coupling and Fusion 133 Horizontal Ground Loop 134 Vertical Ground Loop 134 Surface-Water Systems 135 The Invention of Standardized Geothermal HVAC 138 Closed-Loop Design Considerations 139 Thermal Conductivity Testing and Evaluation 139 Design of the Heat-Exchanger Loop 142 Bin Data and Degree Days 143 Header Design 144 Design of the Geothermal System Including the Heat-Exchanger Field Exchanger Pipe Size Borehole Size Borehole Spacing Length of Borehole per Ton Pumping Power for the Ground Loop 151 Ground-Loop Guidelines 151 Pipe Joining Method: Heat Fusion 152 A Comment from a Geothermal Expert in Switzerland 155 Review Questions Plate-Frame Heat Exchanger: When Is It Needed? 157 What Is a Plate-Frame Heat Exchanger? 157 Electrolysis versus Chemical/Abrasive Wear and Corrosion 157 Electrolysis Conditions 158 When Is a Plate Heat Exchanger Required? 161 Design Cost and Efficiency 161 Freezing Potential 161 Cleaning 162 Best Uses 163 Hydraulic Separators 165 Review Questions Standing Column and Open Geothermal Systems 167 Where Does a Standing-Column Well Fit? 167 Efficiency 169 First Cost 169 Geology 170 Maintenance 170 Regulatory Issues 170 Thermal Stability 171 Designing a Standing-Column Well 175 Standing-Column Wells in the Field 178 Standing-Column Well Controls 189 Offset Piping Layout 190 Bleed Circuit 191 Final Assembly 193

5 yjjj Contents What to Expect 194 Regulatory Factors 195 Glossary 196 Review Questions Fundamentals of Comfort, Psychrometrics, and Thermodynamics 201 What Is Comfort? 201 Engineering Laws of Thermodynamics 206 HVAC Applications of the Laws of Thermodynamics 208 Heating and Cooling Load Calculations 209 Manual Heat Load Calculations 210 Automated Heating and Cooling Load Calculations 212 The Refrigeration Cycle 213 Rating Refrigeration Energy Efficiency 215 Heat Pumps 216 Practical Applications: Effects of Building Construction and HVAC Systems 218 Conclusion 224 Review Questions Heating, Ventilation, and Air-Conditioning System Basics 227 Basic Hydronic Systems 227 Central Plant Components 227 Boilers 227 Chillers 229 Piping 230 Pumps 230 Delivery/Terminal Devices 231 Accessories 232 Alternative Approaches 232 Hydronic Piping Systems 233 Hydronic Terminal Units 237 Basic Air Systems 241 Refrigerant or Direct-Expansion Systems 249 Choosing a System 250 Review Questions Hydronic Heating, Ventilation, and Air-Conditioning System Equipment 255 Closed- and Open-Loop Piping Systems 255 Pumps and Pumping 256 Centrifugal Pumps Overview 256 Centrifugal Pump Types 257 Base-Mounted Centrifugal Pumps 257 Vertical In-line Centrifugal Pumps 257 Horizontal Base-Mounted Centrifugal Pumps 259 Split-Case Centrifugal Pumps 259 Wet-Rotor Centrifugal Pumps 259

6 Contents ix Hydraulic Efficiencies and the Best Efficiency Point 261 Affinity Laws 261 Pump Curves 262 System Curves 262 Parallel Pumping 263 Variable-Speed Pumping 263 Air Elimination 264 Ways to Remove Air 266 Types of Air-Removal Devices 267 Expansion Control 269 Air Control through Pressure Control 269 Pressure Control through Air Control 273 Location of Expansion Tank 275 Air-Cushion Plain-Steel Expansion Tanks 277 Heat Exchangers 279 Types of Heat Exchangers 280 Conclusion 283 Review Questions Variations and Improvements to Hydronic Systems 287 History of Hydronic Systems 287 Modern Hydronic System Innovations 288 Primary-Secondary Piping 288 Closely Spaced or Twin Tees 288 Single-Pipe Hydronic Systems 290 Single-Pipe System Design 292 Temperature Management 292 Secondary-Circuit Control 295 Balancing and Variable-Volume Flow 296 A Modern Single-Pipe System: LoadMatch 296 Radiant-Cooling Systems 298 Chilled-Beam Systems 299 Chilled Ceilings (Panels) 300 Passive Chilled Beams 302 Active Chilled Beams 303 Chilled-Beam System Advantages 304 Chilled-Water Flow 304 Low-Flow Injection Pumping 305 Modern Low-Flow Injection Pumping: The LOFlo System 306 Chilled-Beam System Design Considerations 309 Dedicated Outdoor Air System Design Guidelines 310 Review Questions Control Systems 313 History of Control Systems 313 Pneumatic Controls 313 Direct Digital Controls 315 Types of Control Loops 316

7 X Contents Types of Building Automation Systems 323 Review Questions Load Sharing and Energy Recovery 331 How We Got Here 332 Proper Operation and Calibration of Controls 343 Natatoriums (or Indoor Swimming Pools) 345 The Big Picture for Thermal Advantage 346 Review Questions 349 Efficiencies Calculating System Comparing Water, Air, and Refrigerant Systems 351 Moving British Thermal Units around a Building 353 Radiant Cooling and Chilled Beams 354 Dehumidification 356 Variable-Speed Technology 356 Comparing Energy Efficiency 357 Review Questions Geothermal Rebates, Incentives, and Renewables Legislation 371 Is It Shiny? 373 Commercial Geothermal HVAC Tax Incentives 375 Energy-Efficient Commercial Building Tax Deductions 377 Barriers to Geothermal HVAC Funding 377 Some Current Funding Options Energy Services Companies 378 Property Assessed Clean Energy Funding 378 Energy-Efficiency Power Purchase Agreements 379 Managed Energy Services Agreement 379 Utility Involvement: On-Bill Financing by Electric Utilities Legislative and Political Progress 380 Geothermal Exchange Organization 381 GEO's Focus: Federal and State Levels 382 GEO's 2012 Federal Legislative Issues 383 Successful Outcomes for the Industry 386 GEO Supports State Geothermal Initiatives 388 Review Questions 392 A Geothermal HVAC Resources 395 B Answers to Review Questions 403 Index 405