Greenbriar East Elementary School Fairfax, Virginia Michelle L. Siano Mechanical Option Spring 2005 Senior Thesis

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



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



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



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


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


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



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


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



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



Questions?Questions?

Documents

Greenbriar East Elementary School Fairfax, Virginia Michelle L. Siano Mechanical Option Spring 2005 Senior Thesis