exhaust stack discharge velocity reduction study for labs21 2009

Safely Achievable Reductions Safely Achievable Reductions in Exhaust Fan Energy in in Exhaust Fan Energy in

Laboratory BuildingsLaboratory BuildingsChet Wisner, President, Ambient Air TechnologiesChet Wisner, President, Ambient Air Technologies

Jay Hayashi, P2S EngineeringJay Hayashi, P2S EngineeringMarc Gomez, Director, UCI EH&SMarc Gomez, Director, UCI EH&S

Fred Bockmiller, Principal Engineer, UCI FacilitiesFred Bockmiller, Principal Engineer, UCI FacilitiesChris Abbamonto, Energy Manager, UCI FacilitiesChris Abbamonto, Energy Manager, UCI Facilities

University of California, IrvineUniversity of California, Irvine

Large research universityLarge research university$16M annual utilities budget$16M annual utilities budget

Lab buildings consume 2/3 of campus energyLab buildings consume 2/3 of campus energyMany energy initiatives to reduce carbon footprintMany energy initiatives to reduce carbon footprint

Campus Energy $avings ChallengeCampus Energy $avings Challenge Recipe for SuccessRecipe for Success

SafetyManagement

Visionary & Supportive

UpperManagement

Engineers

FacilityManagersPatience

Team Synergy

Supportive Users/Researchers

AgendaAgenda

Smart Lab Overview Smart Lab Overview Lab Exhaust System ComponentsLab Exhaust System Components Study MethodologyStudy Methodology Wind Tunnel TestingWind Tunnel Testing Cost and Energy SavingsCost and Energy Savings SummarySummary

Can We BuildCan We Build“Smart Labs” “Smart Labs”

that Greatly Reduce that Greatly Reduce Energy Use?Energy Use?

Past PracticesPast Practices

Labs21 Best PracticesLabs21 Best Practices

Smart Lab Stretch Goal: Smart Lab Stretch Goal:

Outperform ASHRAE 90.1/CA Title 24 by 50%Outperform ASHRAE 90.1/CA Title 24 by 50%

Efficient Laboratory Design EvolutionEfficient Laboratory Design Evolution

Smart Laboratory ConceptSmart Laboratory ConceptBalancing Laboratory Safety and Climate SafetyBalancing Laboratory Safety and Climate Safety

Create lab buildings that out perform ASHRAE 90.1 / CA Title 24 by 40-50%. Combine energy initiatives such as centralized demand controlled ventilation (CDCV), low flow (high performance) fume hoods, reduced building exhaust stack airspeeds, and use of energy-efficient lighting.

Building Exhaust System

Labs w/CDCVreal time lab air monitoring4 ach occupied2 ach unoccupied

Energy efficientlighting

Labs with low flow fume hoods(as appropriate)

Centralized Demand Controlled Ventilation (CDCV)Centralized Demand Controlled Ventilation (CDCV)Utilizing real time lab air monitoring, reduce air changes in labs from approximately 6 ACH to 4 ACH while the lab is occupied and 2 ACH when lab is unoccupied.

Low Flow (High Performance) Fume HoodsLow Flow (High Performance) Fume HoodsUtilize fume hoods that are designed to operate safely at lower face velocities, i.e., 70 FPM rather than 100 FPM.

Exhaust plenum

Deeper work surface

Unique airfoil design

Advanced baffle design

Lab Area LPD from 1.1 to 0.55

Lab Prep LPD from 0.9 to 0.36

Prep Room LPD from 2.0 to 1.0

Corridor LPD from 0.6 to 0.3

Laboratory Lighting ControlsLaboratory Lighting ControlsReduce Power Density by 50%Reduce Power Density by 50%

- Daylight sensors for fixtures near windows- Occupancy sensing by lab bay

Lab Building Exhaust Fan Energy ReductionLab Building Exhaust Fan Energy Reduction

Building Exhaust System

Slightly higher stacks

Variable speed fans (wind responsive if necessary)

Air handler with fresh air intake

AgendaAgenda

Smart Lab OverviewSmart Lab Overview Lab Exhaust System ComponentsLab Exhaust System Components Study MethodologyStudy Methodology Wind Tunnel TestingWind Tunnel Testing Cost and Energy SavingsCost and Energy Savings SummarySummary

Can We Reduce Lab Building Can We Reduce Lab Building Exhaust Discharge RatesExhaust Discharge Rates

& Achieve Real Energy Savings & Achieve Real Energy Savings Without Compromising Safety?Without Compromising Safety?

This InitiativeThis Initiative

Lab Building Exhaust Stack Lab Building Exhaust Stack Discharge StudyDischarge Study

Prior to this study, we thought:Prior to this study, we thought:

Wind tunnel testing produces conservative designsWind tunnel testing produces conservative designs Field dispersion studies are not performed on new or Field dispersion studies are not performed on new or

renovated exhaust systemsrenovated exhaust systems Energy savings may be realizedEnergy savings may be realized Find a “one size fits all” solutionFind a “one size fits all” solution

Lab Exhaust Diagram AnimatedLab Exhaust Diagram Animated

Wind

Exhaust Fan Bypass Damper

Plenum

Fume Hood

Supply Fan Duct

Balcony

Re-Entrainment of Contaminated Air

AgendaAgenda

Smart Lab OverviewSmart Lab Overview Lab Exhaust System ComponentsLab Exhaust System Components Study MethodologyStudy Methodology Wind Tunnel TestingWind Tunnel Testing Cost and Energy SavingsCost and Energy Savings SummarySummary

Study MethodologyStudy Methodology

Selection of buildings – characteristics:Selection of buildings – characteristics:

Building size and age Building size and age Number of laboratoriesNumber of laboratories Fume hoods and hazardous contentsFume hoods and hazardous contents Types of fans – constant/variable fans, Types of fans – constant/variable fans,

induced airinduced air Exhaust stack parametersExhaust stack parameters Hazardous exhaust flowHazardous exhaust flow

Study MethodologyStudy Methodology

Final Three buildings:Final Three buildings:

Biological Sciences 3Biological Sciences 3 Natural Sciences 1Natural Sciences 1 Sprague HallSprague Hall

Study MethodologyStudy Methodology

Final three buildings were selected for the Final three buildings were selected for the following characteristics:following characteristics:

Representative of our campus environmentRepresentative of our campus environment Representative exhaust stack parametersRepresentative exhaust stack parameters Significant lab activitySignificant lab activity Induced-air fansInduced-air fans Curved metal roofsCurved metal roofs Manifolded exhaustsManifolded exhausts Modern design approachModern design approach

AgendaAgenda

Smart Lab OverviewSmart Lab Overview Lab Exhaust System ComponentsLab Exhaust System Components Study MethodologyStudy Methodology Wind Tunnel TestingWind Tunnel Testing Cost and Energy SavingsCost and Energy Savings SummarySummary

Wind Tunnel TestingWind Tunnel Testing

Wind Tunnel TestingWind Tunnel Testing

Removing Conservatism Requires Extra Removing Conservatism Requires Extra CareCare More comprehensive wind tunnel testingMore comprehensive wind tunnel testing Commissioning the renovated systemCommissioning the renovated system Educate lab usersEducate lab users

Wind Tunnel TestingWind Tunnel Testing

Build model of campusBuild model of campus

Wind Tunnel TestingWind Tunnel Testing

Build model of campusBuild model of campus Install model stacksInstall model stacks

Wind Tunnel TestingWind Tunnel Testing

Build model of campusBuild model of campus Install model stacksInstall model stacks Install air sampling Install air sampling

points (“receptors”)points (“receptors”)

Wind Tunnel Testing Wind Tunnel Testing MethodologyMethodology

Build model of campusBuild model of campus Install model stacksInstall model stacks Install air sampling Install air sampling

points (“receptors”)points (“receptors”) Ensure correct Ensure correct

approach flowapproach flow

Wind Tunnel Testing Wind Tunnel Testing MethodologyMethodology

Build model of campusBuild model of campus Install model stacksInstall model stacks Install air sampling points Install air sampling points

(“receptors”)(“receptors”) Ensure correct approach Ensure correct approach

flowflow Wind tunnel testingWind tunnel testing Data analysisData analysis

Establish Appropriate Design Establish Appropriate Design CriteriaCriteria

ASHRAE Recommendation for Labs isASHRAE Recommendation for Labs is 400 (µg m 400 (µg m-3-3)/(g s)/(g s-1-1))

ANSI Z9.5 Recommendation for Labs isANSI Z9.5 Recommendation for Labs is 750 (µg m 750 (µg m-3-3)/(g s)/(g s-1-1))

Adjust up or down based on specific Adjust up or down based on specific materials and activities in the labmaterials and activities in the lab

AgendaAgenda

Smart Lab OverviewSmart Lab Overview Lab Exhaust System ComponentsLab Exhaust System Components Study MethodologyStudy Methodology Wind Tunnel TestingWind Tunnel Testing Cost and Energy SavingsCost and Energy Savings SummarySummary

Typical Timeline of Exit Typical Timeline of Exit Velocity RequirementsVelocity Requirements

0102030405060708090

1 3 5 7 9 11 13 15 17 19 21 23

Time

CF

M x

100

0

Typical Design

1% Design

Required by Dispersion

Required by High Air Change Rate

Required by Low AirChange Rate

Energy & Cost SavingsEnergy & Cost SavingsBiological Sciences 3Biological Sciences 3

(based on $0.11/kWh)(based on $0.11/kWh)

ActionsActions SavingsSavings Payback Payback PeriodPeriod

General LaboratoryGeneral LaboratoryIncrease stacks (5 feet)Increase stacks (5 feet)Reduce flow (13,000 cfm/stack)Reduce flow (13,000 cfm/stack)

Up to 58 kWUp to 58 kW

$61K/year$61K/year

1.6 years1.6 years

BSL 3 LaboratoryBSL 3 LaboratoryIncrease stacks (4 feet)Increase stacks (4 feet)Reduce flow (270 cfm/stack)Reduce flow (270 cfm/stack)

Up to 5.6 kWUp to 5.6 kW

$6K/Year$6K/Year

5.1 years5.1 years

Energy & Cost SavingsEnergy & Cost SavingsNatural Sciences 1Natural Sciences 1 (based on $0.11/kWh)(based on $0.11/kWh)

ActionsActions SavingsSavings Payback Payback PeriodPeriod

Safety and Energy SavingsSafety and Energy SavingsIncrease stacks on Nat Sci 1 Increase stacks on Nat Sci 1

(4 feet)(4 feet)Install variable frequency drivesInstall variable frequency drivesInstall wind responsive Install wind responsive

equipmentequipmentReduce exhaust fan flows Reduce exhaust fan flows

Up to 39 kWUp to 39 kW

$41K/year$41K/year

3.7 to 5.3 3.7 to 5.3 yearsyears

Energy & Cost SavingsEnergy & Cost SavingsSprague HallSprague Hall

(based on $0.11/kWh)(based on $0.11/kWh)

ActionsActions SavingsSavings Payback Payback PeriodPeriod

Do not modify exhaust stack heightsDo not modify exhaust stack heights Install Variable Frequency Drives on Install Variable Frequency Drives on

each faneach fanDisable or remove the existing Disable or remove the existing

bypass dampersbypass dampersSet the minimum exhaust flow to Set the minimum exhaust flow to

25,000 cfm (6 air changes)25,000 cfm (6 air changes)

Up to 46 kWUp to 46 kW

$48K/year$48K/year

1.7 years1.7 years

AgendaAgenda

Smart Lab OverviewSmart Lab Overview Lab Exhaust System ComponentsLab Exhaust System Components Study MethodologyStudy Methodology Wind Tunnel TestingWind Tunnel Testing Cost and Energy SavingsCost and Energy Savings SummarySummary

QuestionQuestion

Can We Reduce Laboratory Can We Reduce Laboratory Building Exhaust Stack Building Exhaust Stack

Discharge RatesDischarge Rates& Save Energy & Save Energy

Without Compromising Safety?Without Compromising Safety?

AnswerAnswer

Yes.Yes. Establish design criteria/performance Establish design criteria/performance

guidelinesguidelines Wind tunnel screening studyWind tunnel screening study Audit new and renovated designsAudit new and renovated designs Conduct field commissioning studiesConduct field commissioning studies Sufficient wind tunnel receptorsSufficient wind tunnel receptors

Study SummaryStudy Summary

What we learned:What we learned:

Wind tunnel testing, as it is used in design, is Wind tunnel testing, as it is used in design, is conservativeconservative

Field dispersion studies are not performed on new or Field dispersion studies are not performed on new or renovated exhaust systemsrenovated exhaust systems

Energy savings can be realizedEnergy savings can be realized Didn’t find a “one size fits all” solutionDidn’t find a “one size fits all” solution

Thank You!Thank You!

Review Existing Exhaust Review Existing Exhaust SystemSystem

Review as-built hazardous exhaust Review as-built hazardous exhaust mechanical systemsmechanical systems

Examine system configuration, fan type, Examine system configuration, fan type, redundancy, sequence of operation, etc.redundancy, sequence of operation, etc.

Review exhaust fan curves Review exhaust fan curves CRITICALCRITICAL

Variable volume vs. constant volumeVariable volume vs. constant volume

Smart Labs & Energy $avings Smart Labs & Energy $avings ChallengeChallenge

Balance energy savings & safetyBalance energy savings & safety

Maximize

Energy

Savings

Createa SaferLab

Identify & Test Alternative Identify & Test Alternative Renovation DesignsRenovation Designs

Identify exhaust system renovations which can Identify exhaust system renovations which can be economically implementedbe economically implementedto reduce exit velocitiesto reduce exit velocities

Install VFDsInstall VFDs Stack extensionsStack extensions Manifolding & clusteringManifolding & clustering Re-Sequencing multipleRe-Sequencing multiple

fan setsfan sets

23 = 8a

Energy Proportional to Velocity Cubed

Identify & Test Alternative Identify & Test Alternative Renovation DesignsRenovation Designs

Identify exhaust system renovations which can Identify exhaust system renovations which can be economically implementedbe economically implementedto reduce exit velocitiesto reduce exit velocities

Install VFDsInstall VFDs Stack extensionsStack extensions Manifolding & clusteringManifolding & clustering Re-Sequencing multipleRe-Sequencing multiple

fan setsfan sets

Test the design alternatives in the wind tunnel to Test the design alternatives in the wind tunnel to determine safety of personnel and research determine safety of personnel and research animalsanimals

Commission TestingCommission Testingof Exhaust Dispersionof Exhaust Dispersion

Field tracer gas studyField tracer gas study

Overall check on entire exhaust system Overall check on entire exhaust system including plume dispersionincluding plume dispersion

Ensures margin of safety is actually Ensures margin of safety is actually achievedachieved

AgendaAgenda

Lab Exhaust System ComponentsLab Exhaust System Components Study MethodologyStudy Methodology Wind Tunnel TestingWind Tunnel Testing Cost and Energy SavingsCost and Energy Savings Saving Energy for Your Lab BuildingSaving Energy for Your Lab Building Saving Energy for Your CampusSaving Energy for Your Campus SummarySummary

BYPASSBYPASS

NOT MANIFOLDEDNOT MANIFOLDED

MANIFOLDEDMANIFOLDED

Study MethodologyStudy Methodology

Buildings considered:Buildings considered:

Biological Sciences Biological Sciences Natural Sciences 1Natural Sciences 1 Natural Sciences 2Natural Sciences 2 Croul HallCroul Hall Hewitt HallHewitt Hall Sprague HallSprague Hall Cal-IT2Cal-IT2 Engineering Lab FacilityEngineering Lab Facility Engineering GatewayEngineering Gateway

Wind Tunnel Testing Wind Tunnel Testing MethodologyMethodology

Build model of campusBuild model of campus Install model stacksInstall model stacks Install air sampling points Install air sampling points

(“receptors”)(“receptors”) Ensure correct approach Ensure correct approach

flowflow Wind tunnel testingWind tunnel testing