Utilities Infrastructure Heating Distributio - APPA · Utilities Infrastructure Heating...
Transcript of Utilities Infrastructure Heating Distributio - APPA · Utilities Infrastructure Heating...
APPA Institute – Session 301C EU © GLHN Architects & Engineers,Inc.
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Utilities InfrastructureHeating Distribution
APPA Institute for
Facilities Management
Dallas Jan 2017
Bill Nelson PE
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Purpose of Today’s Presentation
• To share information about currenttechnologies related to central plants
• To provide some useful handoutmaterial with sizing guides
• To provide a broad understanding ofcentral heating distribution systems
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Agenda
• Introduction
Steam Piping System
Radial vs looped
Hot Water Piping
Reverse Return
APPA Institute – Session 301C EU © GLHN Architects & Engineers,Inc.
Design and OperationalIssues
–Heating Media
•Steam
•Hot Water
Steam Systems
–High Press – over 350 psig
–Med Press – 15 to 350 psig
–Low Press – up to 15 psig
Hot Water Systems
–High Temp – over 350 ° F
–Medium Temp – 250 to 350 ° F
–Low Temp – under 250 ° F
APPA Institute – Session 301C EU © GLHN Architects & Engineers,Inc.
Velocity Limits
–Steam 7500 fpm
–Hot water 8 fps (500fpm)
Design Issues
– Thermal Expansion
(anchors, expansion control, pipe guides)
– Insulation (factory applied, field applied)
– Access for Maint and Repair
– Safety
Design Issues
–Building Connections
• Steam
PRV, convertors, traps, meters
• Hot Water
Control valves, pumps, meters
APPA Institute – Session 301C EU © GLHN Architects & Engineers,Inc.
System Architecture
–Radial vs. Looped
–Radial – from plant to load
–Loop – from plant to load & back
Radial vs Looped
–Radial
limited flexibility for expansion
–Loop
ability to expand
easy to isolate
higher cost
more planning required
Radial Piping System
APPA Institute – Session 301C EU © GLHN Architects & Engineers,Inc.
Looped Pipe System
Types of DistributionSystems
–Direct Bury (Boring)
–Utilidors
–Tunnels
Direct Bury Utility Systems
–Poured in place insulation
–Pre-insulated pipe (HDPE)
–Lowest first cost
–Easy installation
–Expansion loops
–Access Vaults
APPA Institute – Session 301C EU © GLHN Architects & Engineers,Inc.
Pipe Boring
–At times the best alternative
–Can be expensive
–Requires excavations at both ends
–Limited flexibility
Utilities Typically Buried
– Steam and Hot Water
– Chilled Water
– Water, Nat Gas, Sewers
– Primary Electrical
HDPE pre-insulated pipe
• Steam or Hot Water Direct Bury
APPA Institute – Session 301C EU © GLHN Architects & Engineers,Inc.
Direct Bury Piping Detail
Trench Detail
Pipe Anchor
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Wall Penetration
Large Direct Bury Project
Expansion Loop
APPA Institute – Session 301C EU © GLHN Architects & Engineers,Inc.
Expansion Joint (winter)
Utilidors
–Shallow covered structure
–Accessible and non-accessible top
–One option -
poured slab with pre-cast top
–More protection and life than bury
–Less costly than tunnels
Utilidor Diagram
APPA Institute – Session 301C EU © GLHN Architects & Engineers,Inc.
Utilidor Design
Pre-Cast Utilidor
Winter time Utilidor
APPA Institute – Session 301C EU © GLHN Architects & Engineers,Inc.
Tunnels
–Big and deep enough to walk in
(some crawl tunnels)
–Tops often sidewalks
–Long Life (50 + years)
–Maximum access
–Greatest flexibility for expansion
–Highest Cost
Tunnels
–Poured in place concrete
–Pre-manufactured
–Typically utilities on one side
–Ventilation
–Lighting & power
–Drains
–Highest first cost
Box Style Tunnel
APPA Institute – Session 301C EU © GLHN Architects & Engineers,Inc.
Box Style Tunnel
Arch Style Tunnel
Arch Style Tunnel
APPA Institute – Session 301C EU © GLHN Architects & Engineers,Inc.
Pre-Manufactured Tunnel
Operation and MaintenanceIssues
– Vaults & manholes (bury & utilidor)
– Structure, joints, seals (utilidors &tunnels)
– Steam
traps, pumps, PRV’s, valves, insulation
– Hot Water
valves, pump seals, insulation
Utility Vault
APPA Institute – Session 301C EU © GLHN Architects & Engineers,Inc.
Pre-Cast Utilidor
• Steam Traps
• Insulation
• Flash Tank
Expansion Joint
APPA Institute – Session 301C EU © GLHN Architects & Engineers,Inc.
Expansion Joint and Anchor
Cost of Construction
–First Cost vs. Life Cycle Cost
–Expandability
–Long Term Reliability
Direct Bury
–Welded pipe for low temp Hot Water
$500 + per foot
–Welded pipe for high temp Hot Water
$700 + per foot
–Welded pipe for Steam
$800 + per foot
–Boring – get estimates
APPA Institute – Session 301C EU © GLHN Architects & Engineers,Inc.
Utilidors
–$2000 to $3000 per ft
–Common size is 5 ft W by 3 ft deep
Tunnels
–$4000 to $7000 per ft
–Common size is 8 ft W by 8 ft H
–But will last 100+ years
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HVAC System:Steam and Condensate
• General Arrangement
Boiler Feed Pumps Condensate Pumps
Deaerator
Condensate Tank
Boiler
Building
APPA Institute – Session 301C EU © GLHN Architects & Engineers,Inc.
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Steam Piping Design• Distribution System Types
• Walking Tunnel
• Shallow Tunnel
• Direct Buried
• Material Types
• Carbon Steel (ANSI B 16.9 A106)
• Other
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Piping Design• Insulation Types
• Factory applied (Perma Pipe)
• Field applied
• Pitch
• Velocity/pressure limits
• Condensate Returns/Trapping
• Effect of Leaks
• Expansion devices
• Supports/guides/anchors
• Hookups/Accessories
APPA Institute – Session 301C EU © GLHN Architects & Engineers,Inc.
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Condensate Return-Traps• Typical Application
• Types
• Thermostatic
• Liquid expansion
• Balanced pressure
• Bimetallic
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Condensate Return-Traps• Types (cont’d)
• Mechanical
• Bucket
• Float
• Thermodynamic
• Impulse
• Disc
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Typical Application
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Mechanical-Float & Thermostatic
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Expansion-Basic Restraint
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Expansion-Sliding Joint
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Expansion-Bellows
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Hookup-Main Drips
Bad
Good
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Hookup-Takeoff
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Waterhammer-Steam Induced
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Tunnel Flooding-Condensate Generation
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STEAM SYSTEM PIPING CAPACITY 1000 lb/hr(1000 ft2)
[HP]
Steam QuantityAreaFeedwater Pump HP
This chart is intended to be used for obtaining an initialestimate of required pipe size and cost. Actual systemdesign must be based on values obtained specifically forthe project. Total installed cost per linear ft. of buriedsupply & return (2 pipes) piping. Price includes trenching,insulation, fittings, backfill & moderate amounts ofsurfacing repairs. For total project cost add A-E fees,testing, escalations, contingencies, etc.
Building SQFT values are based on 60 Btuh/sqft peakaverage combined load (building heat and domestichot water). For winter lows below +25 F: at 0 Fmultiply building SQFT by 0.8, at -20 F multiply buildingSQFT by 0.6.
Steam lines are sized to approximately 10,000 ft/min.
Condensate lines are sized to approximately yieldpressure drops less than 2’/100’.
Prices shown are construction cost for a direct burieddual conduit piping system.