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2002-2003 AE Senior Thesis Allison M Clarke
Capital One Northern Virginia Campus ConsolidationCapital One Northern Virginia Campus ConsolidationMcLean, VAMcLean, VA
Comparison of Air Distribution Comparison of Air Distribution SystemsSystemsUnderfloor Air
vs.Ceiling-Based Systems
2002-2003 AE Senior Thesis Allison M Clarke
Capital One Northern Virginia Campus ConsolidationCapital One Northern Virginia Campus ConsolidationMcLean, VAMcLean, VA
Presentation OutlineExisting Building & SystemsUnderfloor Air DistributionCeiling-Based SystemComparisonConclusion & Recommendations
Introduction
Existing Building & Systems
Underfloor Air System
Ceiling-Based System
Comparison
Recommendation
Conclusions
2
2002-2003 AE Senior Thesis Allison M Clarke
Capital One Northern Virginia Campus ConsolidationCapital One Northern Virginia Campus ConsolidationMcLean, VAMcLean, VA
Project TeamOwner - Capital One Financial Corporation
Owner’s Rep - Jones Lang LaSalle
Architect - Ai Architecture
GC - James G. DAVIS Construction
Structural Engr - Rathgeber/Goss Associates
MEP Engr - Ai Engineering
Introduction
Existing Building & Systems
Underfloor Air System
Ceiling-Based System
Comparison
Recommendation
Conclusions
2002-2003 AE Senior Thesis Allison M Clarke
Capital One Northern Virginia Campus ConsolidationCapital One Northern Virginia Campus ConsolidationMcLean, VAMcLean, VA
ArchitectureIntroduction
Existing Building & Systems
Underfloor Air System
Ceiling-Based System
Comparison
Recommendation
Conclusions
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2002-2003 AE Senior Thesis Allison M Clarke
Capital One Northern Virginia Campus ConsolidationCapital One Northern Virginia Campus ConsolidationMcLean, VAMcLean, VA
Location & Site1600 Scotts Crossing Road McLean, VA26 AcresBorders I-495 Capital Beltway
Introduction
Existing Building & Systems
Underfloor Air System
Ceiling-Based System
Comparison
Recommendation
Conclusions
StructureBase Building – Floors 1 & 2
Cast-in-Place Concrete with Post Tension BeamsTower – Floors 3 – 14
Steel StructureConcrete Slab on Metal Deck18” Raised Concrete CoreTypical Floor Space
2002-2003 AE Senior Thesis Allison M Clarke
Capital One Northern Virginia Campus ConsolidationCapital One Northern Virginia Campus ConsolidationMcLean, VAMcLean, VA
Introduction
Existing Building & Systems
Underfloor Air System
Ceiling-Based System
Comparison
Recommendation
Conclusions
MechanicalUnderfloor Air Distribution System in TowerFour 600 ton Chillers4-Cell Cooling TowerTwo 22,000 cfm AHU’s per Typical Floor
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2002-2003 AE Senior Thesis Allison M Clarke
Capital One Northern Virginia Campus ConsolidationCapital One Northern Virginia Campus ConsolidationMcLean, VAMcLean, VA
Underfloor Air DistributionBackground InformationSystem ComponentsConstruction Methods/ScheduleEnergy UseCostsLessons Learned
Introduction
Existing Building & Systems
Underfloor Air System
Ceiling-Based System
Comparison
Recommendation
Conclusions
2002-2003 AE Senior Thesis Allison M Clarke
Capital One Northern Virginia Campus ConsolidationCapital One Northern Virginia Campus ConsolidationMcLean, VAMcLean, VA
Background InformationAlternative to conventional ceiling-based air distribution systemsPreviously used for spaces with high heat loadsIntroduces air at floor level
Occupied Zone – floor to head levelUnoccupied Zone – head level to ceiling
Introduction
Existing Building & Systems
Underfloor Air System
Ceiling-Based System
Comparison
Recommendation
ConclusionsOccupied Zone
Unoccupied Zone
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2002-2003 AE Senior Thesis Allison M Clarke
Capital One Northern Virginia Campus ConsolidationCapital One Northern Virginia Campus ConsolidationMcLean, VAMcLean, VA
Background InformationBenefits
Improved thermal comfort for occupantsImproved ventilation efficiency & indoor air qualityReduced energy use from mechanical systemsReduced life cycle building costsReduced floor-to-floor height in new constructionImproved occupant satisfaction and productivity
Introduction
Existing Building & Systems
Underfloor Air System
Ceiling-Based System
Comparison
Recommendation
Conclusions
2002-2003 AE Senior Thesis Allison M Clarke
Capital One Northern Virginia Campus ConsolidationCapital One Northern Virginia Campus ConsolidationMcLean, VAMcLean, VA
Background InformationBarriers
New & unfamiliar technologyPerceived higher costsLack of information & design guidelinesLimited applicability to retrofit constructionProblems with applicable standards & codesProblems with spillage and dirt entering underfloor plenumConcerns of condensation and dehumidification problems
Introduction
Existing Building & Systems
Underfloor Air System
Ceiling-Based System
Comparison
Recommendation
Conclusions
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2002-2003 AE Senior Thesis Allison M Clarke
Capital One Northern Virginia Campus ConsolidationCapital One Northern Virginia Campus ConsolidationMcLean, VAMcLean, VA
System ComponentsTypical Floor
Two 22,000 cfm AHU’s28 fan powered terminal boxes supply perimeterStatic pressure sensors22,500 sf Access floor panelsPassive & VAV floor diffusers
Introduction
Existing Building & Systems
Underfloor Air System
Ceiling-Based System
Comparison
Recommendation
Conclusions
Source: Tate Access Floors
Typical Mechanical Room Section
2002-2003 AE Senior Thesis Allison M Clarke
Capital One Northern Virginia Campus ConsolidationCapital One Northern Virginia Campus ConsolidationMcLean, VAMcLean, VA
Construction Methods/ScheduleLocal Jurisdiction Code Requirements
Underfloor is a plenum
Supply Air DiffusersRedundant installation
Underfloor Air SpaceMoisture concerns
Above Ceiling Air SpaceSuspended ceiling not absolutely necessary
Introduction
Existing Building & Systems
Underfloor Air System
Ceiling-Based System
Comparison
Recommendation
Conclusions
7
2002-2003 AE Senior Thesis Allison M Clarke
Capital One Northern Virginia Campus ConsolidationCapital One Northern Virginia Campus ConsolidationMcLean, VAMcLean, VA
Construction Methods/ScheduleTypical Floor Schedule
219 Work Days
Introduction
Existing Building & Systems
Underfloor Air System
Ceiling-Based System
Comparison
Recommendation
Conclusions
2002-2003 AE Senior Thesis Allison M Clarke
Capital One Northern Virginia Campus ConsolidationCapital One Northern Virginia Campus ConsolidationMcLean, VAMcLean, VA
Construction Methods/ScheduleTower Schedule
289 Work Days
Introduction
Existing Building & Systems
Underfloor Air System
Ceiling-Based System
Comparison
Recommendation
Conclusions
8
2002-2003 AE Senior Thesis Allison M Clarke
Capital One Northern Virginia Campus ConsolidationCapital One Northern Virginia Campus ConsolidationMcLean, VAMcLean, VA
Energy UseTypical Floor Design Loads
72060
Total Tower Load(tons)
Typical Floor Load(tons)
Introduction
Existing Building & Systems
Underfloor Air System
Ceiling-Based System
Comparison
Recommendation
Conclusions
Design Load Distribution
39%
29%
14%
10%
8% OA Load (tons)
Lighting Load(tons)Equipment Load(tons)Envelope Load(tons)Occupant Load(tons)
2002-2003 AE Senior Thesis Allison M Clarke
Capital One Northern Virginia Campus ConsolidationCapital One Northern Virginia Campus ConsolidationMcLean, VAMcLean, VA
Energy UseAnnual Energy Consumption
Binmaker Weather Data3,120 hours
Introduction
Existing Building & Systems
Underfloor Air System
Ceiling-Based System
Comparison
Recommendation
Conclusions
701,35258,446Total Ton-hours
Total TowerTypical Floor
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2002-2003 AE Senior Thesis Allison M Clarke
Capital One Northern Virginia Campus ConsolidationCapital One Northern Virginia Campus ConsolidationMcLean, VAMcLean, VA
CostConstruction Costs
$ 13.66 per square foot $ 5,136,160 Tower Cost
Operating CostsEnergy Consumption 2,912,721 kWhAnnual Cost $ 206,803
Lifecycle Cost30 years $ 9,084,118
Introduction
Existing Building & Systems
Underfloor Air System
Ceiling-Based System
Comparison
Recommendation
Conclusions
2002-2003 AE Senior Thesis Allison M Clarke
Capital One Northern Virginia Campus ConsolidationCapital One Northern Virginia Campus ConsolidationMcLean, VAMcLean, VA
Lessons LearnedMoisture detection in underfloor plenum
Outdoor air load oversized20 cfm/occupant needed43 cfm/occupant used
“Green” technologyRecognized by USGBC
Introduction
Existing Building & Systems
Underfloor Air System
Ceiling-Based System
Comparison
Recommendation
Conclusions
10
2002-2003 AE Senior Thesis Allison M Clarke
Capital One Northern Virginia Campus ConsolidationCapital One Northern Virginia Campus ConsolidationMcLean, VAMcLean, VA
Introduction
Existing Building & Systems
Underfloor Air System
Ceiling-Based System
Comparison
Recommendation
Conclusions
Ceiling-Based System• Background Information• System Components• Construction Methods/Schedule• Energy Use• Costs• Lessons Learned
2002-2003 AE Senior Thesis Allison M Clarke
Capital One Northern Virginia Campus ConsolidationCapital One Northern Virginia Campus ConsolidationMcLean, VAMcLean, VA
Background InformationTraditional approach to HVAC designAir supplied & returned at ceiling
Conditions entire space
Introduction
Existing Building & Systems
Underfloor Air System
Ceiling-Based System
Comparison
Recommendation
ConclusionsConditioned Space
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2002-2003 AE Senior Thesis Allison M Clarke
Capital One Northern Virginia Campus ConsolidationCapital One Northern Virginia Campus ConsolidationMcLean, VAMcLean, VA
Background InformationBenefits
Designers & contractors more familiarCheaper to buildAvailable standards & codesSuspended ceiling systems made access easierCurrently found in most U.S. buildings
Introduction
Existing Building & Systems
Underfloor Air System
Ceiling-Based System
Comparison
Recommendation
Conclusions
2002-2003 AE Senior Thesis Allison M Clarke
Capital One Northern Virginia Campus ConsolidationCapital One Northern Virginia Campus ConsolidationMcLean, VAMcLean, VA
Background InformationBarriers
No individual controlExpensive to modify or reconfigureCan be noisyUsually cramped into ceiling plenum with other systems
Introduction
Existing Building & Systems
Underfloor Air System
Ceiling-Based System
Comparison
Recommendation
Conclusions
12
2002-2003 AE Senior Thesis Allison M Clarke
Capital One Northern Virginia Campus ConsolidationCapital One Northern Virginia Campus ConsolidationMcLean, VAMcLean, VA
Introduction
Existing Building & Systems
Underfloor Air System
Ceiling-Based System
Comparison
Recommendation
Conclusions
System ComponentsTypical Floor
Two 22,000 cfm AHU’sVAV box & thermostat controlled zones
Perimeter zonesInterior zones
Ducted supply, return air plenum
Source: Trane
2002-2003 AE Senior Thesis Allison M Clarke
Capital One Northern Virginia Campus ConsolidationCapital One Northern Virginia Campus ConsolidationMcLean, VAMcLean, VA
Construction Methods/ScheduleTypical Floor Schedule
181 Work Days
Introduction
Existing Building & Systems
Underfloor Air System
Ceiling-Based System
Comparison
Recommendation
Conclusions
13
2002-2003 AE Senior Thesis Allison M Clarke
Capital One Northern Virginia Campus ConsolidationCapital One Northern Virginia Campus ConsolidationMcLean, VAMcLean, VA
Construction Methods/ScheduleTower Schedule
290 Work Days
Introduction
Existing Building & Systems
Underfloor Air System
Ceiling-Based System
Comparison
Recommendation
Conclusions
2002-2003 AE Senior Thesis Allison M Clarke
Capital One Northern Virginia Campus ConsolidationCapital One Northern Virginia Campus ConsolidationMcLean, VAMcLean, VA
Introduction
Existing Building & Systems
Underfloor Air System
Ceiling-Based System
Comparison
Recommendation
Conclusions
Energy UseTypical Floor Design Loads
72060
Total Tower Load(tons)
Typical Floor Load(tons)
Design Load Distribution
39%
29%
14%
10%
8% OA Load (tons)
Lighting Load(tons)Equipment Load(tons)Envelope Load(tons)Occupant Load(tons)
14
2002-2003 AE Senior Thesis Allison M Clarke
Capital One Northern Virginia Campus ConsolidationCapital One Northern Virginia Campus ConsolidationMcLean, VAMcLean, VA
Energy UseAnnual Energy Consumption
Binmaker Weather Data3,120 hours
Introduction
Existing Building & Systems
Underfloor Air System
Ceiling-Based System
Comparison
Recommendation
Conclusions
701,35258,446Total Ton-hours
Total TowerTypical Floor
2002-2003 AE Senior Thesis Allison M Clarke
Capital One Northern Virginia Campus ConsolidationCapital One Northern Virginia Campus ConsolidationMcLean, VAMcLean, VA
CostConstruction Costs
$ 10.18 per square foot $ 3,827,680 Tower Cost
Operating CostsEnergy Consumption 3,470,577 kWhAnnual Cost $ 246,410
Lifecycle Cost30 years $ 8,531,753
Introduction
Existing Building & Systems
Underfloor Air System
Ceiling-Based System
Comparison
Recommendation
Conclusions
15
2002-2003 AE Senior Thesis Allison M Clarke
Capital One Northern Virginia Campus ConsolidationCapital One Northern Virginia Campus ConsolidationMcLean, VAMcLean, VA
Lessons LearnedMajor mechanical equipment are correct sizes
Due to underfloor system being oversized
Introduction
Existing Building & Systems
Underfloor Air System
Ceiling-Based System
Comparison
Recommendation
Conclusions
2002-2003 AE Senior Thesis Allison M Clarke
Capital One Northern Virginia Campus ConsolidationCapital One Northern Virginia Campus ConsolidationMcLean, VAMcLean, VA
ComparisonIntroduction
Existing Building & Systems
Underfloor Air System
Ceiling-Based System
Comparison
Recommendation
Conclusions$ 3,827,680$ 246,410$ 8,531,753
$ 5,136,160$ 206,803$ 9,084,118
Costs:ConstructionOperatingLifecycle
3,470,577 kWh2,912,721 kWhEnergy Use
181 work days290 work days
219 work days289 work days
Construction Schedule:Typical Floor12 Floors
Two AHU’s/floorSupply ductControl zones
Two AHU’s/floorAccess floor panelsSwirl diffusers
System Components
Ceiling-Based System
Underfloor System
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2002-2003 AE Senior Thesis Allison M Clarke
Capital One Northern Virginia Campus ConsolidationCapital One Northern Virginia Campus ConsolidationMcLean, VAMcLean, VA
RecommendationDedicate chiller plant equipment to areas utilizing underfloor air
distribution
Two systems:Base building – Floors 1 & 2
Supply air temperature at 58˚FTower – Floors 3 – 14
Supply air temperature at 65˚F
Introduction
Existing Building & Systems
Underfloor Air System
Ceiling-Based System
Comparison
Recommendation
Conclusions
2002-2003 AE Senior Thesis Allison M Clarke
Capital One Northern Virginia Campus ConsolidationCapital One Northern Virginia Campus ConsolidationMcLean, VAMcLean, VA
RecommendationReduction in Cooling Coil Load
Underfloor system requires almost ½ the load
Introduction
Existing Building & Systems
Underfloor Air System
Ceiling-Based System
Comparison
Recommendation
Conclusions
Underfloor System:
Load = (1.08) x (44,000cfm) x (77-65F) / (12,000 Btu/hr/ton)
Load = 48 tons
Ceiling-Based System:
Load = (1.08) x (44,000cfm) x (77-55F) / (12,000 Btu/hr/ton)
Load = 87 tons
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2002-2003 AE Senior Thesis Allison M Clarke
Capital One Northern Virginia Campus ConsolidationCapital One Northern Virginia Campus ConsolidationMcLean, VAMcLean, VA
Recommendation“Snowball Effect”
Cooling Coil Load Decreases
Air Handling Unit Size Decreases
Chiller Size Decreases
Less Cooling Water Needed / Lower GPM
Smaller Pumps
Introduction
Existing Building & Systems
Underfloor Air System
Ceiling-Based System
Comparison
Recommendation
Conclusions
2002-2003 AE Senior Thesis Allison M Clarke
Capital One Northern Virginia Campus ConsolidationCapital One Northern Virginia Campus ConsolidationMcLean, VAMcLean, VA
Conclusions
Underfloor air distribution system
Easy to reconfigure office spaceMore productive workersPotential for energy savings
Future phases of project use design changes
Introduction
Existing Building & Systems
Underfloor Air System
Ceiling-Based System
Comparison
Recommendation
Conclusions
18
2002-2003 AE Senior Thesis Allison M Clarke
Capital One Northern Virginia Campus ConsolidationCapital One Northern Virginia Campus ConsolidationMcLean, VAMcLean, VA
Acknowledgements
DAVIS ConstructionRon Juban, Bill Moyer, Josh Peters, Mike Pittsman
AE FacultyDr. Messner, Prof. Freihaut, Jonathan Dougherty
My ClassmatesEspecially Becky & Joe
Introduction
Existing Building & Systems
Underfloor Air System
Ceiling-Based System
Comparison
Recommendation
Conclusions
2002-2003 AE Senior Thesis Allison M Clarke
Capital One Northern Virginia Campus ConsolidationCapital One Northern Virginia Campus ConsolidationMcLean, VAMcLean, VA
QuestionsIntroduction
Existing Building & Systems
Underfloor Air System
Ceiling-Based System
Comparison
Recommendation
Conclusions
