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Greenbriar East Elementary Greenbriar East Elementary SchoolSchool
Fairfax, VirginiaFairfax, Virginia
Michelle L. SianoMichelle L. SianoMechanical OptionMechanical Option
Spring 2005 Senior ThesisSpring 2005 Senior Thesis
Presentation OutlinePresentation Outline
Project BackgroundProject Background Current Mechanical SystemCurrent Mechanical System Redesign ObjectivesRedesign Objectives Mechanical RedesignMechanical Redesign Daylighting RedesignDaylighting Redesign ConclusionsConclusions AcknowledgementsAcknowledgements QuestionsQuestions
Greenbriar East Elementary Greenbriar East Elementary SchoolSchool
Project BackgroundProject Background Location: Fairfax, VirginiaLocation: Fairfax, Virginia
Site: 10 acres surrounded by Site: 10 acres surrounded by residential neighborhoodsresidential neighborhoods
Building Size: Building Size: – 59,000 sq. ft. renovation59,000 sq. ft. renovation– 14,000 sq. ft. addition14,000 sq. ft. addition– Total of 73,000 sq. ft. Total of 73,000 sq. ft.
when completewhen complete
Dates of Construction: Dates of Construction: – December 2003 - January 2006December 2003 - January 2006
Construction Cost: $6.8 millionConstruction Cost: $6.8 million
Project TeamProject Team
OwnerOwner– Fairfax County Public SchoolsFairfax County Public Schools
Architect/EngineersArchitect/Engineers– Hayes, Seay, Mattern and Mattern Hayes, Seay, Mattern and Mattern
(HSMM)(HSMM)
General ContractorGeneral Contractor– Caldwell and Santmyer, Inc.Caldwell and Santmyer, Inc.
HSMM
Presentation OutlinePresentation Outline
Project BackgroundProject Background Current Mechanical SystemCurrent Mechanical System Redesign ObjectivesRedesign Objectives Mechanical RedesignMechanical Redesign Daylighting RedesignDaylighting Redesign ConclusionsConclusions AcknowledgementsAcknowledgements QuestionsQuestions
Current Mechanical SystemCurrent Mechanical System
ClassroomsClassrooms– Served by a Served by a
Dedicated Dedicated Outdoor Air Outdoor Air System (DOAS) System (DOAS) with a Parallel with a Parallel Unit Ventilator Unit Ventilator SystemSystem
– 5 100% OA units 5 100% OA units ranging in size ranging in size from 1,480 to from 1,480 to 2,460 cfm2,460 cfm
Space
Current Mechanical SystemCurrent Mechanical System
Non-classroom spacesNon-classroom spaces– Constant Volume SystemConstant Volume System– Served by 7 rooftop units ranging in size Served by 7 rooftop units ranging in size
from 1,750 to 8,050 cfmfrom 1,750 to 8,050 cfm– Rooftop units provide full ventilation, Rooftop units provide full ventilation,
heating, and coolingheating, and coolingRA
OA SARTU
Current Mechanical SystemCurrent Mechanical SystemEvaluationEvaluation
ASHRAE Standard 62-2001ASHRAE Standard 62-2001ASHRAE Standard 62-2001 Compliance
0
1000
2000
3000
4000
5000
6000
7000
RTU-1
RTU-2
RTU-3
RTU-4
RTU-5
RTU-6
RTU-7
MAU-1
MAU-2
MAU-3
MAU-4
MAU-5
Unit
Ven
tila
tio
n A
irfl
ow
(C
FM
)Design Ventilation Required Ventilation
Required – 26,910 cfmRequired – 26,910 cfm Designed – 16,110 cfmDesigned – 16,110 cfm
Presentation OutlinePresentation Outline
Project BackgroundProject Background Current Mechanical SystemCurrent Mechanical System Redesign ObjectivesRedesign Objectives Mechanical RedesignMechanical Redesign Daylighting RedesignDaylighting Redesign ConclusionsConclusions AcknowledgementsAcknowledgements QuestionsQuestions
Redesign ObjectivesRedesign Objectives
Meet ASHRAE Standard 62Meet ASHRAE Standard 62– Removes indoor air pollutants from the spaceRemoves indoor air pollutants from the space– Results in better health among the occupantsResults in better health among the occupants
Provide humidity controlProvide humidity control– Minimizes the potential for bacterial growthMinimizes the potential for bacterial growth– Mold can trigger asthma attacksMold can trigger asthma attacks
Asthma has risen 49% since 1982Asthma has risen 49% since 1982
Use energy efficient equipment to lower Use energy efficient equipment to lower operating costsoperating costs
Presentation OutlinePresentation Outline
Project BackgroundProject Background Current Mechanical SystemCurrent Mechanical System Redesign ObjectivesRedesign Objectives Mechanical RedesignMechanical Redesign Daylighting RedesignDaylighting Redesign ConclusionsConclusions AcknowledgementsAcknowledgements QuestionsQuestions
Mechanical RedesignMechanical Redesign
Provides ventilation air Provides ventilation air and meets some of the and meets some of the thermal loadsthermal loads
BenefitsBenefits– always meet always meet
ventilation ventilation requirements due to a requirements due to a lack of mixinglack of mixing
– reduces amount of reduces amount of ventilation airventilation air
– reduces duct and reduces duct and equipment sizesequipment sizes
Supply Airflow Comparison Between the Current System and DOAS
Unit
CurrentSystem
SupplyAirflow (cfm)
DOASSupply Airflow
(cfm)
RTU-1 2595 279
RTU-2 8095 3507
RTU-3 5160 819
RTU-4 4000 1133
RTU-5 1750 478
RTU-6 1840 436
RTU-7 1840 431
MAU-1 1645 3544
MAU-2 1650 3803
MAU-3 1480 3307
MAU-4 2255 1963
MAU-5 2460 3501
TOTAL 34770 23201
Dedicated Outdoor Air SystemDedicated Outdoor Air System
Mechanical RedesignMechanical RedesignDOAS EquipmentDOAS Equipment
Energy Recovery Energy Recovery Units by SemcoUnits by Semco– EPHC Model - EPHC Model -
Enthalpy Wheel Enthalpy Wheel plus full heating plus full heating and coolingand cooling
8 units needed 8 units needed of approx. 3000 of approx. 3000 cfmcfm
$33,000 - $33,000 - $39,000$39,000
Mechanical RedesignMechanical RedesignDOAS EquipmentDOAS Equipment
Reduction in Coil Reduction in Coil SizesSizes
Energy Recovery Unit Cooling Loads
0
50000
100000
150000
200000
250000
0 2 4 6 8 10
Energy Recovery Unit
Co
olin
g L
oa
d (
BT
Uh
)
Without Enthalpy Wheel With Enthalpy Wheel
Energy Recovery Unit Heating Loads
0
50000
100000
150000
200000
1 2 3 4 5 6 7 8
Energy Recovery Unit
He
ati
ng
Lo
ad
(B
TU
h)
Without Enthalpy Wheel With Enthalpy Wheel
29% Reduction in
Cooling Coil
46% Reduction in
Heating Coil
Mechanical RedesignMechanical RedesignParallel SystemParallel System
Geothermal Heat PumpsGeothermal Heat Pumps– Dependent on large amounts of water or groundDependent on large amounts of water or ground– Utilizes the constant temperature of the groundUtilizes the constant temperature of the ground
Results in highly efficient systemResults in highly efficient system
HPHP
Ground Loop
Refrigerant Loop
Mechanical RedesignMechanical RedesignParallel SystemParallel System
Console Units for Console Units for Classroom spacesClassroom spaces– Allows for reuse of Allows for reuse of
current piping for current piping for refrigerant looprefrigerant loop
Horizontal Ceiling Horizontal Ceiling units for non-units for non-classroom spacesclassroom spaces– Serve multiple Serve multiple
spacesspaces
Heat Pump
Mechanical RedesignMechanical RedesignParallel SystemParallel System
Ground LoopGround Loop– Sized for 55.4 tons of heating vs. 52 Sized for 55.4 tons of heating vs. 52
tons of coolingtons of cooling– Typical Soil – 200-300 ft/tonTypical Soil – 200-300 ft/ton
Sized based on 250 ft/ton Sized based on 250 ft/ton 13,573 ft of 13,573 ft of ground pipeground pipe
Cost of $750/ton Cost of $750/ton $41,550 for piping $41,550 for piping and installationand installation
Mechanical RedesignMechanical RedesignDOAS SavingsDOAS Savings
Chilled Water System
Current System Redesigned System
UnitCapacity
(MBH)GPM Unit
Capacity(MBH)
GPM
Make-up Air Units 462.0 92.4
Fan Coil Units 111.3 22.1
Unit Ventilators 1157.2 230.5
TOTAL 1730.5 345.0 TOTAL 0 0
Hot Water System
Current System Redesigned System
UnitCapacity
(MBH)GPM Unit
Capacity(MBH)
GPM
Make-up Air Units 679.0 67.9Energy Recovery Units 754.0 75.4
Cabinet Heaters 258.9 25.8 Cabinet Heaters 258.9 25.8
Unit Heaters 101.2 10.1 Unit Heaters 101.2 10.1
Fan Coil Units 79.2 8.5
Unit Ventilators 781.5 80.3
Fin Tube Radiators 20.6 2.0
TOTAL 1920.4 194.6 TOTAL 1114.1 111.3
Mechanical RedesignMechanical RedesignDOAS SavingsDOAS Savings
Mechanical System Energy Cost Estimates
GasUtilization
Gas CostElectricityUtilization
Electric Cost Total Cost
Current System 1920.4 $ 97,514.07 1730.5 $ 70,200.50 $ 167,714.57
Redesigned System 1114.1 $ 56,571.77 0 $ - $ 56,571.77
Savings 806.3 $ 40,942.30 1730.5 $ 70,200.50 $ 111,142.80
Presentation OutlinePresentation Outline
Project BackgroundProject Background Current Mechanical SystemCurrent Mechanical System Redesign ObjectivesRedesign Objectives Mechanical RedesignMechanical Redesign Daylighting RedesignDaylighting Redesign ConclusionsConclusions AcknowledgementsAcknowledgements QuestionsQuestions
Basis for EvaluationBasis for Evaluation
Daylighting AnalysisDaylighting Analysisfor Current Classroomfor Current Classroom
Average IlluminanceAverage Illuminance– 2.94 fc2.94 fc
Maximum Maximum IlluminanceIlluminance– 41.8 fc41.8 fc
Minimum Minimum IlluminanceIlluminance– 0.3 fc0.3 fc
Classroom RedesignClassroom Redesign
Eight 2’ x 3’ Eight 2’ x 3’ windows at 5’ from windows at 5’ from finished floorfinished floor
Daylighting AnalysisDaylighting Analysisfor Classroom Redesignfor Classroom Redesign
Average IlluminanceAverage Illuminance– 12.86 fc12.86 fc
Maximum Maximum IlluminanceIlluminance– 33.5 fc33.5 fc
Minimum Minimum IlluminanceIlluminance– 0.7 fc0.7 fc
Presentation OutlinePresentation Outline
Project BackgroundProject Background Existing ConditionsExisting Conditions Current Mechanical SystemCurrent Mechanical System Redesign ObjectivesRedesign Objectives Mechanical RedesignMechanical Redesign Daylighting RedesignDaylighting Redesign ConclusionsConclusions AcknowledgementsAcknowledgements QuestionsQuestions
ConclusionsConclusions
DOASDOAS– Reduced Ventilation Quantity by 33%Reduced Ventilation Quantity by 33%– ERUs utilized enthalpy wheels to reduce heating ERUs utilized enthalpy wheels to reduce heating
and cooling loadsand cooling loads Geothermal Heat PumpsGeothermal Heat Pumps
– Utilize the constant temperature of the ground for Utilize the constant temperature of the ground for heating and coolingheating and cooling
CombinationCombination– Removes need for chillerRemoves need for chiller– Saves $111,000 in energy use for chilled and hot Saves $111,000 in energy use for chilled and hot
water systemswater systems Daylighting RedesignDaylighting Redesign
– Improved average illuminance to 12.86 fcImproved average illuminance to 12.86 fc
Presentation OutlinePresentation Outline
Project BackgroundProject Background Current Mechanical SystemCurrent Mechanical System Redesign ObjectivesRedesign Objectives Mechanical RedesignMechanical Redesign Daylighting RedesignDaylighting Redesign ConclusionsConclusions AcknowledgementsAcknowledgements QuestionsQuestions
AcknowledgementsAcknowledgements
AE Faculty and StaffAE Faculty and Staff– Dr. FreihautDr. Freihaut
HSMMHSMM– Mike KirkpatrickMike Kirkpatrick– Cortney HoughlandCortney Houghland
Fairfax County Public SchoolsFairfax County Public Schools– Dave BeckerDave Becker
My family, James, and friendsMy family, James, and friends
Presentation OutlinePresentation Outline
Project BackgroundProject Background Current Mechanical SystemCurrent Mechanical System Redesign ObjectivesRedesign Objectives Mechanical RedesignMechanical Redesign Daylighting RedesignDaylighting Redesign ConclusionsConclusions AcknowledgementsAcknowledgements QuestionsQuestions
Questions?Questions?