In urban areas, moving hot and cold air efficiently is essential. By connecting suitable customer heat and cold demands with available heat and cold sources, resource use can be lower when compared to conventional heat and cold supply, such as boilers and air conditioners. Chapters about the fundamental idea, energy markets, customer demands, load variations, supply, environmental impact, distribution, substations, system functioning, economics, planning, historical development, current and future use, organization, and information sources concerning the flows of heat and cold in district heating and cooling systems are included.

11 Preface 15 Chapter 1 Introduction 17 Chapter contents 20 Terminology and nomenclature 22 Literature 23 Chapter 2 The fundamental idea of district heating 29 Literature 29 Study questions for Chapter 2 31 Chapter 3 Energy, heat, and cold markets 31 Energy markets 35 Literature 35 Heat markets 38 Cold markets 42 Literature 43 Study questions for Chapter 3 45 Chapter 4 Heat and cold demands 45 Space heating 56 Literature 56 Domestic hot water supply 59 Literature 60 Specific heat use in buildings 62 Literature 63 Industrial heat demands 64 Literature 64 Other heat demands 65 Literature 66 Cold demands 68 Literature 69 Study questions for chapter 4 71 Chapter 5 Heat and cold loads 71 Heat load definition 72 Aggregate heat loads before substations 80 Distribution heat losses 80 Heat loss calculations 85 Temperature drop in the respective directions of flow 85 Annual heat losses 88 Literature 89 Heat and cold loads in distribution networks 91 Aggregate heat loads after heat supply units 91 Seasonal heat load variations 92 Heat load weather dependence 95 Daily heat load variations 98 Heat load composition 99 Short-term heat load forecasting 100 Literature 100 Heat load parameters 100 Diversity 101 Capacity utilisation 109 Design heat load 110 Literature 111 Cold loads 116 Literature 116 Study questions and problems for chapter 5 119 Chapter 6 Heat and cold supply 119 A wide range of possible energy supply sources 128 Boilers and solid fuel combustion 141 Literature 142 Flue gas cleaning and flue gas condensation 142 Flue gas cleaning 145 Boiler efficiency and flue gas condensation 151 Combined flue gas cleaning and condensation 152 Literature 153 Combined heat and power 154 The CHP concept 156 Basic CHP idea illustrated by a gas turbine plant 159 Performance measures 162 Back pressure steam cycle CHP plant 170 High efficiency steam CHP plant 171 Extraction-condensing steam CHP plant 176 Theoretical Carnot cycle CHP plant 178 Combined cycle CHP plant 180 Small-scale CHP plant 190 Normalised P-Q diagram with efficiency measures 191 CHP versus small-scale heat pumps 195 Carbon capture and storage CHP 196 Literature 198 Waste incineration (Waste-to-Energy 202 Literature 203 Heat recycling from industrial processes 210 Literature 210 Polygeneration 212 Literature 212 Geothermal district heating and cooling 212 Overview 213 Size of the geothermal resource 214 Ground source heat pumps, a definition issue 214 Geographical distribution and temperature levels 216 Geothermal district heating technology 218 Geothermal combined heat and power 222 Literature 223 Large-scale ambient cold sources 224 Literature 226 Large heat pumps and chillers 226 Vapour compression heat pumps and chillers 235 Absorption heat pumps and chillers 243 Literature 244 Solar district heating and cooling 248 Literature 249 Nuclear district heating 251 Literature 252 Electric boilers 253 Peak and backup heat generation 257 Literature 258 Heat and cold storage 259 Load shifting 261 Short-time heat storage technology and flowcharts 265 Short-time cold storage technology 268 Literature 268 Study questions and problems for Chapter 6 271 Chapter 7 Environmental impact and opportunities 271 Local and regional air quality 275 Benefits of district cooling 275 Climate change 278 Literature 279 7.4 Environmental opportunities – summing up 280 Study questions and problems for Chapter 7 281 Chapter 8 Heat and cold distribution technology 281 Historical development of heat distribution technology 282 First generation: Steam distribution 287 Second generation: Hot water distribution inside ducts 290 On the way to third-generation heat distribution technology 292 The third generation of heat distribution technology 296 Literature 297 Joints 299 Valves 303 Literature 304 Durability and methods of laying rigid pipes 304 Stress-based design of carrier pipes of rigid, bonded pipe assemblies 308 Solid mechanics of restrained thermal expansion 312 Pipe-laying methods 316 Strain- and fatigue-based design of carrier pipes 322 Literature 323 Insulation foam and jacket pipes 329 Literature 330 Insulation sizing 336 Literature 336 Underground installation of rigid pipes 342 Literature 342 Flexible pipes 348 Literature 348 Overland pipes, pipes in tunnels, and pipes inside houses 349 Literature 350 Number of pipes in parallel 352 Literature 353 Cold carrier distribution 359 Literature 360 Water chemistry 366 Literature 366 Study questions and problems for chapter 8 369 Chapter 9 Substations 369 The substation concept 372 Literature 373 Desired temperature performance 375 Literature 375 Hydraulic separation 379 Examples of detailed layouts 385 Literature 385 Cascading 388 Literature 389 Selection of equipment 389 Heat exchangers 392 Valves and controls 396 Hot water storage tanks 400 Testing the equipment 400 Literature 401 Sizing of equipment 401 Overall considerations 405 Heat exchangers 410 Hot water storage tanks 410 Control valves 413 Literature 414 Adapting hydronic space heating systems 414 Energy saving measures 414 Elimination of recirculation and three-way valves 418 Optimised radiator flow rate and supply temperature 419 Single-pipe hydronic heating systems 420 Literature 421 District cooling substations 427 Literature 427 Metering in substations 440 Literature 441 Study questions and problems for Chapter 9 443 Chapter 10 System functioning 443 Grid structures and maps 443 Heat density 445 Typical growth structures 447 Typical network structures 449 Developed network structure 450 Regional district heating systems 452 Literature 453 Heat and cold distribution 454 Flow distribution 454 Pressure drop 458 Pumping power 459 Pressure head gradients and pressurisation 467 Pressure surges 469 Carrier pipe sizing and choice of flow velocity 473 Literature 475 Temperature levels 481 Literature 482 Heat demand and load control 484 Grid control and four operating modes 487 Central maximum supply temperature control 487 Local minimum supply temperature control at the grid periphery 487 Central and local maximum pressure control 488 Central and local minimum pressure control 488 Four operating modes 490 System responses to altered demand conditions 491 Dynamic load responses 493 Literature 493 Heat supply from multiple sources 496 System monitoring 496 Short term planning 498 System supervision 499 Documentation and analyses 499 Literature 500 Reliability and availability issues 500 Reliability level 502 Operating problems 504 Maintenance 505 Literature 507 Development of system functioning 509 Study questions and problems for Chapter 10 511 Chapter 11 Economics and planning 513 Cash flow based profitability analysis 514 Present value and the Net Present Value decision rule 516 Investment periods and hurdle rates in district heating 517 Profitability in existing operations 518 Valuation of incremental investments 518 Allocation of synergy benefits 524 Literature 525 Heat supply optimisation 530 Literature 531 Distribution costs 536 Literature 537 Extension planning 540 Literature 541 Price models 544 Literature 544 Heat supply costs versus local energy efficiency measures 547 Literature 547 Economy-of-size 548 District cooling 550 Study questions and problems for chapter 11 553 Chapter 12 District heating and cooling development 553 District heating 558 Literature 559 District cooling 564 Literature 565 Future district heating and cooling 566 Structure definition 571 Identification 571 Adaptation 572 Study questions and problems for chapter 12 573 Chapter 13 Organisation 573 Legislation 574 Literature 574 Market rules 577 Literature 578 Ownership 580 Literature 580 Study questions and problems for Chapter 13 581 Chapter 14 Information sources 581 Textbooks 582 Literature 582 Handbooks 583 Literature 583 Journals 585 Conferences 585 Statistics 587 Literature 588 Trade associations 588 Research programs 590 Literature 591 Index