1、DISTRICT COOLING GUIDEComprehensive ReferencePlanning also includes information onoperations and maintenance and comprehensive terminology for district cooling“- Provided by publisher.ISBN 978-1-936504-42-8 (softcover)1. Air conditioning from central stations-Handbooks, manuals, etc. I. American Soc
2、iety of Heating, Refrigerating andAir-Conditioning Engineers.TH7687.75.D47 2013697.93-dc232013012051ASHRAE Staff Special Publications Mark S. Owen, Editor/Group Manager of Handbook and Special PublicationsCindy Sheffield Michaels, Managing EditorJames Madison Walker, Associate EditorRoberta Hirschbu
3、ehler, Assistant EditorSarah Boyle, Editorial AssistantMichshell Phillips, Editorial CoordinatorPublishing Services David Soltis, Group Manager of Publishing Services and Electronic CommunicationsJayne Jackson, Publication Traffic AdministratorTracy Becker, Graphics SpecialistPublisher W. Stephen Co
4、mstockFront1.fm Page iv Wednesday, May 29, 2013 3:01 PMAcknowledgmentsxiAcronyms.xiiiPurpose and Scope. 1.1District Cooling Background. 1.1Applicability 1.1Components 1.2Benefits. 1.3Environmental Benefits1.3Economic Benefits.1.3Typical Applications 1.4References 1.4Introduction 2.1Establish and Cla
5、rify Owners Scope 2.3Development of the Database. 2.4Alternative Development 2.5Codes and Standards2.5Local and Institutional Constraints .2.8Integrated Processes.2.8Phased Development and Construction.2.8Central Plant Siting 2.8Chiller Selection .2.9Chilled-Water Distribution Systems2.10Constructio
6、n Considerations and Cost.2.11Consumer Interconnection2.12Energy Cost2.13Operations and Maintenance Costs .2.14Economic Analysis and User Rates. 2.14Conclusions 2.15References 2.19Chapter 1 IntroductionChapter 2 System PlanningContentsFront2_TOC.fm Page v Wednesday, May 29, 2013 3:01 PMviDistrict Co
7、oling GuidePlant Components and Alternative Arrangements 3.1Temperature Design Basis for the Central Plant 3.2Chiller Basics 3.3Chiller Types.3.3Chiller Performance Limitations3.4Electrical-Driven Water-Cooled Centrifugal Chillers3.8Engine-Driven Chillers .3.8Absorption Chillers 3.9Chiller Configura
8、tion. 3.13Chiller Staging 3.14Chiller Arrangements and Pumping Configurations . 3.15Chiller Arrangements .3.15Circulating Fundamentals3.15Pumping Schemes 3.20Plant Pumping3.20Pressure Gradient in CHW Distribution Systems.3.21Distribution Network Pumping System Configurations .3.25CHW Primary Pumping
9、 Configuration 3.28Plant Condenser Pumping Arrangement3.30Condenser-Water Piping and Pumping forUnequal Numbers of Chillers and Cooling Towers 3.31Pumps 3.31Heat Rejection 3.32Heat Rejection Equipment.3.33Condenser Water 3.33Cooling Towers. 3.34Tower Selection .3.35Fan Speed Type.3.38Draft Type.3.39
10、Tower Basin .3.40Tower Fill Options3.42Materials of Construction3.43Water Sources3.43Water Filtration Systems. 3.46Air Venting 3.48Plant Piping and Insulation. 3.51Mechanical Room Design . 3.52Electrical Room Design. 3.54References 3.55Bibliography 3.55Introduction 4.1Distribution System Types 4.2Pi
11、ping and Jacketing Materials. 4.4Steel4.4Copper4.6Ductile Iron.4.6Cementitious Pipe4.6FRP.4.7Chapter 3 Central PlantChapter 4 Distribution SystemsFront2_TOC.fm Page vi Wednesday, May 29, 2013 3:01 PMContentsviiPVC.4.7PE and HDPE .4.7Piping Systems Considerations 4.7Leak Detection 4.11Cathodic Protec
12、tion 4.11Geotechnical Considerations 4.13Valve Vaults and Entry Pits. 4.14Valve Vault Issues 4.15Thermal Design Conditions. 4.18Soil Thermal Properties 4.19Soil Thermal Conductivity4.21Temperature Effects on Soil Thermal Conductivity and Frost Depth4.20Specific Heats of Soils.4.21Undisturbed Soil Te
13、mperatures 4.22Heat Transfer at Ground Surface 4.24Insulations and their Thermal Properties . 4.28Steady-State Heat Gain Calculations for Systems 4.28Single Un-Insulated Buried Pipe .4.29Single Buried Insulated Pipe .4.31Two Buried Pipes or Conduits 4.32When to Insulate District Cooling Piping 4.35I
14、mpact of Heat Gain.4.35Cost of Additional Chiller Plant Capacity4.36Impacts of Heat Gain on Delivered Supply Water Temperature4.39References 4.41Temperature Differential Control 5.1Connection Types. 5.2Direct Connection. 5.3Indirect Connection .5.6Components 5.7Heat Exchangers5.7Flow Control Devices
15、.5.11Instrumentation and Control5.12Temperature Measurement.5.13Pressure Measurement5.13Pressure Control Devices5.14Metering 5.14References 5.16Overview of TES Technology and Systems for District Cooling 6.1TES Technology Types 6.4Latent Heat TES.6.4Sensible Heat TES .6.7Comparing TES Technologies.6
16、.10Drivers for and Benefits of Employing TES in Distict Cooling Systems 6.10Primary Benefits of Using TES in District Cooling Systems 6.10Potential Secondary Benefits of Using TES in District Cooling Systems6.11Chapter 5 END USER INTERFACEChapter 6 THERMAL ENERGY STORAGEFront2_TOC.fm Page vii Wednes
17、day, May 29, 2013 3:01 PMviiiDistrict Cooling GuideSystem Integration 6.12Location of TES Equipment.6.12Hydraulic Integration of TES .6.14Sizing and Operation of TES. 6.17Full versus Partial-shift TES Systems.6.17Daily versus Weekly Cycle TES Configurations .6.19TES Control6.19Economics of TES in Di
18、strict Cooling . 6.20Capital Costs6.20An Actual Case Study of TES for District Cooling,with Economics (Andrepont and Kohlenberg 2005)6.21References 6.22Bibliography 6.23General . 7.1BMS or SCADA? 7.1Major Differences.7.1Summary 7.2System Components. 7.2Management Layer7.3Communication Layer7.3Automa
19、tion Layer.7.3Field Instruments Layer.7.4System Configuration . 7.5System Structure .7.5Plant Control Room .7.6System Features and Capabilities 7.7Operation Philosophy 7.8The ICMS for Plant Management7.8Control Philosophy Statement 7.8ICMS Global Monitoring and Alarming Procedure.7.12Interface with
20、BMS 7.13Rotation Sequence 7.13Energy and Operational Considerations . 7.14Condenser-Water Return Temperature Setpoint Reset.7.14CHWS Temperature Setpoint Reset .7.14TES Tanks 7.15 Introduction 8.1Workplace Safety 8.1Security. 8.2Water Treatment. 8.2Corrosion8.2Corrosion Protection and Preventive Mea
21、sures 8.3White Rust on Galvanized Steel Cooling Towers.8.4Scale Control 8.5Nonchemical Methods.8.6External Treatments.8.6Chapter 7 INSTRUMENTATION AND CONTROLSChapter 8 OPERATION AND MAINTENANCEFront2_TOC.fm Page viii Wednesday, May 29, 2013 3:01 PMContentsixBiological Growth Control. 8.6Control Mea
22、sures.8.7Legionnaires Disease8.10Suspended Solids and Deposition Control 8.10Mechanical Filtration8.11Selection of Water Treatment. 8.14Once-Through Systems (Seawater or Surface Water Cooling) .8.14Open Recirculating Systems (Cooling Towers)8.14Closed Recirculating Systems (Distribution System).8.15
23、European Practice in Closed Distribution Systems .8.16Water Treatment in Steam Systems .8.16Maintenance . 8.16References 8.17Integration with Heating and Power Generation. 9.1Unconventional Working Fluids 9.2References 9.3Case Study: Business Bay Executive Towers .A.1System Overview A.1System Perfor
24、mance Metrics. A.1Chiller Details A.1Pumping . A.2Water Treatment . A.2Cooling Towers . A.2Distribution System. A.2Consumer Interconnect A.3Special Features . A.3Contact for More Information. A.3Case Study: Texas Medical Center.A.4System Overview A.4System Performance Metrics. A.4Chiller Details A.4
25、Pumping A.4Water Treatment . A.4Cooling Towers . A.4Thermal Storage A.5Distribution System. A.5Consumer Interconnect A.5Special Features . A.5Contact for More Information. A.5Case Study: District Cooling St. PaulA.7System Overview A.7System Performance Metrics. A.7Electric Details A.7Chiller Details
26、 A.7Water Treatment . A.7Cooling Towers A.7Thermal Storage A.7Chapter 9 SYSTEM ENHANCEMENTSAppendix A CASE STUDIESFront2_TOC.fm Page ix Wednesday, May 29, 2013 3:01 PMxDistrict Cooling GuideDistribution System. A.8Consumer Interconnect A.8Special Features . A.8Environmental and Economic Benefits A.8
27、Published Articles on the System or Websites with Details . A.8Contact for More Information. A.8B.1Appendix B TERMINOLOGY FOR DISTRICT COOLINGFront2_TOC.fm Page x Wednesday, May 29, 2013 3:01 PMThe principal investigator and authors would like to thank the members of the ProjectMonitoring Subcommitt
28、ee (PMS) for their patience through the long process of creatingthis document. This includes many discussions of scope and content as well as the actualreview. This document has benefited tremendously from the careful review of the PMSmembers and their many suggestions based on the vast and diverse
29、knowledge of districtheating that their composite experience represents.The chair of the PMS, Steve Tredinnick, deserves special recognition for the count-less hours he has invested in this effort both in his role as the PMS chair and as a majorunpaid contributor and a sounding board for the princip
30、al investigator.Gary PhetteplaceJanuary 2013AcknowledgmentsFront3_Acknowledgments.fm Page xi Wednesday, May 29, 2013 3:03 PMFront3_Acknowledgments.fm Page xii Wednesday, May 29, 2013 3:03 PMABS acrylonitrile butadiene styreneAEE Association of Energy EngineersAFD adjustable-frequency driveAHRI Air-C
31、onditioning, Heating, and Refrigeration InstituteASME American Society of Mechanical EngineersASCE American Society of Civil EngineersBOD biochemical oxygen demandBMS building management systemsCFU colony-forming unitCEC California Energy CommissionCEN European Committee for StandardizationCFD compu
32、tational fluid dynamicsCHP combined heat all of that growth was districtcooling in the Middle East.APPLICABILITYDCSs are best used in markets where the thermal load density is high and the numberof equivalent full load hours of cooling (or operating hours) is high. A high load density isneeded to co
33、ver the capital investment for the transmission and distribution system, whichusually constitutes a significant portion of the capital cost for the overall system, oftenamounting to 50% or more of the total cost. This makes DCSs most attractive in servingdensely populated urban areas and high-densit
34、y building clusters with high thermal loads,especially tall buildings. Urban settings where real estate is very valuable are good places1IntroductionChapter 1.fm Page 1 Wednesday, May 29, 2013 3:04 PM1.2District Cooling Guidefor DCSs since they allow building owners to make maximum use of their foot
35、print bymoving most of the cooling equipment off-site. Low-density residential areas have usuallynot been attractive markets for district cooling. The equivalent full load hours of cooling areimportant because the DCS is capital intensive and maximum use of the equipment is nec-essary for cost recov
36、ery.COMPONENTSDCSs consist of three primary components: the central plant(s), the distribution net-work, and the consumer systems or customers interconnection (i.e., energy transfer sta-tion or ETS); seeFigure 1.1 District cooling system.Figure 1.1. In the central plant (see Chapter 3) chilled water
37、 is producedby one or more of the following methods:Absorption refrigeration machinesElectric-driven compression equipment (reciprocating, rotary screw, or centrifu-gal chillers)Gas/steam turbine or engine-driven compression equipmentCombination of mechanically driven systems and thermal energy driv
38、en absorp-tion systemsThe second component is the distribution or piping network that conveys the chilledwater (see Chapter 4). The piping may be the most expensive portion of a DCS. Chilledwater piping usually consists of uninsulated or preinsulated directly buried systems. Thesenetworks require su
39、bstantial permitting and coordinating with nonusers of the system forright-of-way if the networks are not on the owners property. Because the initial cost ishigh, it is important to maximize the use of the distribution piping network.The third component is the consumer interconnection to the distric
40、t cooling distribu-tion system, which includes in-building equipment. Chilled water may be used directly bythe building systems or isolated indirectly by a heat exchanger (see Chapter 5).Chapter 1.fm Page 2 Wednesday, May 29, 2013 3:04 PM1Introduction1.3BENEFITSEnvironmental BenefitsGenerating chill
41、ed water in a central plant is normally more efficient than using in-buildingequipment (i.e., decentralized approach) and thus the environmental impacts are normallyreduced. The greater efficiencies arise due to the larger, more efficient equipment and the abilityto stage that equipment to closely m
42、atch the load yet remain within the equipments range ofhighest efficiency. DCSs may take advantage of diversity of demand across all users in the sys-tem and may also implement technologies such as thermal storage more readily than individualbuilding cooling systems. For electric-driven district coo
43、ling plants, higher efficiency becomesthe central environmental benefit since in-building plants are normally electric driven as well.There may be additional environmental benefits from cooling supplied from a large centralplant, such as the ability to use treated sewage effluent as cooling tower ma
44、keup water and theability to handle refrigerants in a safer and more controlled environment.When fuels are burned to generate cooling via absorption or gas/steam turbine and/orengine-driven chillers, emissions from central plants are easier to control than those fromindividual plants, and on an aggr
45、egate generate less pollutants due to higher quality ofequipment, higher seasonal efficiencies, and higher level of maintenance. A central plantthat burns high-sulfur coal can economically remove noxious sulfur emissions, whereindividual combustors could not. Similarly, the thermal energy from munic
46、ipal wastes canprovide an environmentally sound system, an option not likely to be available on a build-ing scale system.Refrigerants and other chemicals can be monitored and controlled more readily in acentral plant. Where site conditions allow, remote location of the plant reduces many ofthe conce
47、rns with the use of ammonia systems for cooling.Economic BenefitsA DCS offers many economic benefits. Even though the basic costs are still borne bythe central plant owner/operator, because the central plant is large, the customer can real-ize benefits of economies of scale.Operating PersonnelOne of
48、 the primary advantages for a building owner is that operating personnel for theHVAC system can be reduced or eliminated. Most municipal codes require operatingengineers to be on site when high-pressure boilers, as would be used to drive absorptionchillers, are in operation. Some older systems requi
49、re trained operating personnel to be inthe boiler/mechanical room at all times. When chilled water is brought into the buildingas a utility, depending on the sophistication of the building HVAC controls, there willlikely be opportunity to reduce or eliminate operating personnel.InsuranceBoth property and liability insurance costs may be significantly reduced with theelimination of boilers, chillers, pumps, and electrical switch gear from within the buildingsince risk of a fire or accident is reduced.Usable SpaceUsable space in the building increases when a boile
