ashrae aedg k12.ppt [read-only] - ashrae® kansas …€¦ · · 2011-09-28poor hydronic...

ASHRAE Kansas City 4/17/08 1

Kirk Mescher, PEKirk Mescher, PE

EducationEducation

Performance Innovation ExperiencePerformance Innovation Experience

Wxá|zÇ

ASHRAEASHRAEAEDG KAEDG K--1212

Why Geothermal Why Geothermal HVAC Systems Fill The BillHVAC Systems Fill The Bill

P PESimply Efficient

1ENGINEERING

Bright Solutions in Engineering

ENGINEERING

2ASHRAE Kansas City 4/17/08


AEDG ComponentsAEDG Components

Problem IdentificationProblem IdentificationGoal SettingGoal Setting-- Overall SYSTEM EfficiencyOverall SYSTEM Efficiency

Building envelopeBuilding envelopeSystemsSystemsLighting and PowerLighting and PowerOperationOperationService Water heatingService Water heating

VerificationVerificationTraining Training OperationOperation


Goal SettingGoal Setting


DOE Climatic ZonesDOE Climatic Zones


Determining an Energy BudgetDetermining an Energy BudgetEPA-Energy Budget SoftwareDeveloped By Stephen Kavanaugh, Phd.


Where is the energy used?Where is the energy used?

Source: ASHRAE AEDG K-12 2008


Compliance ResponsibilitiesCompliance Responsibilities


Prescriptive ApproachPrescriptive Approach


System ChoicesSystem Choices


The GoalThe Goal-- Provide an effective efficient Provide an effective efficient engineering solution to the client.engineering solution to the client.

Identifying the problemIdentifying the problemEvaluate System Load ComponentsEvaluate System Load ComponentsIdentify Possible system solutionsIdentify Possible system solutionsDesign an effective efficient engineering solutionDesign an effective efficient engineering solution

RenewablesRenewablesSystem ComplexitySystem ComplexitySystem CostSystem Cost


Load IdentificationLoad Identification

What are the primary components of the HVAC load?What are the primary components of the HVAC load?RoofRoofWallWallFenestrationFenestrationVentilationVentilationOccupantsOccupantsInternal LoadsInternal Loads


Cooling Load Components

Solar Loads

Wall transmission

Roof transmission

Glass transmission

Door transmission

Floor Transmission

Lighting

Power

People

10% Safety

Ventilation

Fans

Load IdentificationLoad Identification

Ventilation Represents 30Ventilation Represents 30--40% of Load40% of Load

Ventilation

Envelope

PeoplePower Lights

Solar

Conduction/ envelope represents Conduction/ envelope represents <20%<20% of the system loadof the system load


Identifying the Big Targets?Identifying the Big Targets?

50%


Enthalpy Energy Recovery Enthalpy Energy Recovery


20

40

60

80

100

120

0 20 40 60 80 100

Dry Bulb Temperature - Degree F

Hum

idity

Rat

io -

Gra

ins o

f Moi

stur

e

5

15

25

35

Enthalpy - BTU per

Pound Dry Air

Energy Recovery: The Real StoryEnergy Recovery: The Real Story

Outdoor Air conditions to HVAC System with Total Energy Recovery Preconditioning (TERS)

Outdoor air conditions to HVAC system without energy recovery


Load ResultsLoad Results

Total Transmission lossesTotal Transmission losses-- 118,000 Btuh118,000 BtuhSolar LoadSolar Load-- 57,000 Btuh57,000 BtuhVentilation Load (2700 CFM) 117,000 BtuhVentilation Load (2700 CFM) 117,000 Btuh

Energy Savings Potential for 75% effective ERVEnergy Savings Potential for 75% effective ERV

88,000 BTUH88,000 BTUH


This Means?This Means?

Building transmission losses are dictated by envelope Building transmission losses are dictated by envelope configuration and materials.configuration and materials.Building internal heat gains are controlled by lighting Building internal heat gains are controlled by lighting and use of the building.and use of the building.System Energy use is dictated by efficiencySystem Energy use is dictated by efficiency-- (system (system selection)selection)

Simulation shows that the Building EER for the cooling Simulation shows that the Building EER for the cooling system is 13.5system is 13.5When energy recovery is taken into account, Building EER When energy recovery is taken into account, Building EER raises to 14.3raises to 14.3System EER is improved by 6%System EER is improved by 6%


Want to control Humidity??Want to control Humidity??


What does this mean for the What does this mean for the architect?architect?

Envelope trade offs are not allowed. The base design Envelope trade offs are not allowed. The base design must comply with Standard 90.1.must comply with Standard 90.1.To gain building efficiencyTo gain building efficiency--

The base building must exceed envelope requirementsThe base building must exceed envelope requirementsControl of lighting and internal heat producing appliances is asControl of lighting and internal heat producing appliances is asimportant as a good envelopeimportant as a good envelopeMechanical Engineer Must select efficient systems which Mechanical Engineer Must select efficient systems which controlcontrol

Ventilation Control Ventilation Control High mechanical efficiencyHigh mechanical efficiencyGood space control.Good space control.


Heat pump / Unitary approachHeat pump / Unitary approach

When Speaking of water to air heat pumps a few questions should be considered during design.

1- Do these systems require constant temperature water?2- Do these systems require constant flow?3- What is their static pressure capacity?4- Should I use VAV distribution with them?


A High Efficiency SystemA High Efficiency System

Provide a demand centered heating, cooling and Provide a demand centered heating, cooling and ventilation systemventilation systemSimplified System DesignSimplified System DesignSimple maintenance and operator interface Simple maintenance and operator interface Low first costLow first cost


Components of System efficiencyComponents of System efficiency

Fan powerFan powerPump PowerPump PowerChilling equipment powerChilling equipment powerHeating Equipment energyHeating Equipment energyDuct sizingDuct sizingPipe sizingPipe sizingFiltration SelectionFiltration SelectionMaintenanceMaintenance


Pumping PowerPumping Power

Rather than looking at improved equipment Rather than looking at improved equipment efficiency look at equipment loads.efficiency look at equipment loads.


System Efficiency KillersSystem Efficiency Killers

Poor Hydronic DesignPoor Hydronic DesignHigh pump horse powersHigh pump horse powersControl malfunction / poor designControl malfunction / poor designPoor Duct DesignPoor Duct DesignImproper filter selection and filter maintenanceImproper filter selection and filter maintenanceThe moose on the loose The moose on the loose –– outside air control.outside air control.


What is next?What is next?

What % of building load is conduction?What % of building load is conduction?What % of building load is Occupancy Driven?What % of building load is Occupancy Driven?Can Mechanical systems be designed thatCan Mechanical systems be designed that

Are occupancy driven and control humidity with Are occupancy driven and control humidity with occupancy ?occupancy ?Are properly sized to meet Unoccupied loads?Are properly sized to meet Unoccupied loads?


Getting Started with Ground SourceGetting Started with Ground Source

ReferencesReferencesASHRAE Commercial Geothermal System design ASHRAE Commercial Geothermal System design Manual Manual –– Rafferty and KavanaughRafferty and KavanaughASHRAE HVAC SimplifiedASHRAE HVAC Simplified-- KavanaughKavanaughGCHPCALCGCHPCALC-- Loop sizing program Loop sizing program ––Steve Steve KavanaughKavanaughIGSHPAIGSHPA-- Various articlesVarious articles


A Few A Few ““Ground RulesGround Rules””

Central Pumping is a Parasitic load Central Pumping is a Parasitic load NO MORE THAN 5HP/100 tons of coolingNO MORE THAN 5HP/100 tons of cooling

Loops spacing must be kept 20Loops spacing must be kept 20’’ on centerson centersThermally enhanced grout which is pumped into the Thermally enhanced grout which is pumped into the BOTTOM of the heat exchanger (BOTTOM of the heat exchanger (BentoniteBentonite has a TC has a TC of .3)of .3)Conduct Test Bore and Thermal Conductivity Test in Conduct Test Bore and Thermal Conductivity Test in the DESIGN phase of the projectthe DESIGN phase of the projectUse Design Conditions of 85Use Design Conditions of 85ººF and 45F and 45ººFFKeep it simple, Avoid Buzzers and Bells.Keep it simple, Avoid Buzzers and Bells.


Ground Source SystemsGround Source Systems

Can have Higher first costsCan have Higher first costsBudget ConsiderationsBudget Considerations

Well Drilling Well Drilling –– 20002000--3000 $/ton of cooling3000 $/ton of coolingCompressor noise must be evaluatedCompressor noise must be evaluatedMust be Simply implemented to provide superior Must be Simply implemented to provide superior energy efficiency.energy efficiency.

VAV systems add residual minimum static pressure to the air VAV systems add residual minimum static pressure to the air distribution systems. Some zones may require reheat to distribution systems. Some zones may require reheat to maintain conditions during minimum flow.maintain conditions during minimum flow.Do we need to discuss multi zone applications? Simultaneous Do we need to discuss multi zone applications? Simultaneous heating and cooling during shoulder seasons.heating and cooling during shoulder seasons.


Why Simply Designed?Why Simply Designed?

Basically its $Basically its $Boiler and tower plants 1100Boiler and tower plants 1100--1800 $/ton1800 $/tonWell DrillingWell Drilling-- 2000 2000 -- 3000 $/ton3000 $/tonAnnual Energy savings 175Annual Energy savings 175--250 $/ton250 $/tonPayback on boiler plant 4Payback on boiler plant 4--7 years, without regard for 7 years, without regard for maintenance costs.maintenance costs.

Complexity adds $ but does not add VALUEComplexity adds $ but does not add VALUE


Typical Complex AdditionsTypical Complex Additions

Variable speed pumping systemsVariable speed pumping systemsMotorized valves at each unitMotorized valves at each unitDDC controlDDC control-- 66--12 points per unit12 points per unitVariable Volume Boxes with hot water reheatVariable Volume Boxes with hot water reheat


Maintenance Costs Maintenance Costs -- ASHRAEASHRAE

Various HVAC Systems Maintenance Costs in 2004 Dollars ($/ft2-yr)

Age of System (Years)0 2 5 10 20

GSHP (WLHP less Cooling Tower)* 0.208$ 0.215$ 0.226$ 0.243$ 0.277$

WLHP 0.360$ 0.367$ 0.378$ 0.395$ 0.429$

DX-Cooling/Electric Heating 0.382$ 0.388$ 0.399$ 0.416$ 0.450$

2-Pipe Fan Coil w/ CI Boiler & Recip Chiller 0.523$ 0.530$ 0.541$ 0.558$ 0.592$

VAV w/ Firetube Boiler & Recip Chiller 0.634$ 0.641$ 0.651$ 0.668$ 0.703$ 4-Pipe Fan Coil w/ CI Boiler & Recip Chiller 0.686$ 0.693$ 0.703$ 0.720$ 0.755$

* Cooling Tower Reduction Estimate not in ASHRAE ChapterOriginal work in 1983 dollars, here inflated to 2004 dollars using US Dept of Commerce CPI rate of 1.90ASHRAE 1995 Applications Handbook, Chapter 33, Table 4Based upon analysis by Dohrmann and Alereza (1986)Costs are from office buildings only


Geothermal DesignGeothermal Design(the bucket theory)(the bucket theory)

Flow into the bucket =Heat of rejection from Heat pumps

Leak out of the bucket =Thermal capacity of the well field

Bucket volume =Short term thermal Capacity of the well field

Level =

Temperature rise

Temperature fall


What Are Geothermal SystemsWhat Are Geothermal Systems

Geothermal Well FieldThermal Storage

HVAC System with Recycled Energy

Thermal Conductivity

Heating Season

Cooling Season


Hybrid SystemsHybrid Systems

Beyond the scope of this presentation but:Beyond the scope of this presentation but:Hybrid systems offer a way to balance the energy Hybrid systems offer a way to balance the energy load on a well field. load on a well field. In cooling dominated climates, a supplemental fluid In cooling dominated climates, a supplemental fluid cooler would be necessary to put a well field in cooler would be necessary to put a well field in balance. The heating load would be much smaller balance. The heating load would be much smaller and the well field could be designed to meet the and the well field could be designed to meet the heating requirement. heating requirement.


Thermal Conductivity TestingThermal Conductivity Testing

y = 5.1007Ln(x) + 64.27

R2 = 0.9806

0

10

20

30

40

50

60

70

80

90

0 5 10 15 20 25 30 35 40 45 50

GPM

temp in

temp out

average Temp

Log. (average Temp)

Time Period Slope Average He (Btu/hr-ft) at Input (W/ft) Thermal Conductivity (Btu/hr-ft-°F)

10—44 4.3 72.5 21.25 1.34


The Conventional WayThe Conventional Way

System flow is designed to provide 12ºF at the loop field.

12ºF

M M M

PD VFD

T T T


The SolutionThe Solution

Geothermal heat pumpsGeothermal heat pumpsSimplified piping Simplified piping design design Thermostat operator Thermostat operator interfaceinterfaceOccupied and Unoccupied operational modesOccupied and Unoccupied operational modesMERV 6 to 10 filtrationMERV 6 to 10 filtrationLower classroom noise levels over previous unit ventilation Lower classroom noise levels over previous unit ventilation systemssystemsSpace by Space demand oriented systemSpace by Space demand oriented system


Well Field SizingWell Field Sizing

Thermal Conductivity testing provides essential information for Thermal Conductivity testing provides essential information for the sizing of well fieldthe sizing of well fieldEnergy Simulations which indicate the Energy Simulations which indicate the ““PulsesPulses”” of energy to the of energy to the well field are essential to field designwell field are essential to field designTest bore is essential to describe the drilling conditions and Test bore is essential to describe the drilling conditions and methods to contractorsmethods to contractorsMaximumMaximum Heat exchanger DepthHeat exchanger Depth--500 ft.500 ft.RememberRemember-- the ground is a heat sink and a heat source without the ground is a heat sink and a heat source without proper energy inputs the heat sink will be oversized or proper energy inputs the heat sink will be oversized or undersized.undersized.Continuous operation of poorly designed pumps represent a Continuous operation of poorly designed pumps represent a significant load on the well field (cooling load).significant load on the well field (cooling load).


Sample Well FieldSample Well FieldHDPE SDR 11UNI-LOOP

Thermally enhanced grout

Total Field Pressure Loss20’ H20

20’ MIN

Once it’s in the ground, you can add to it but you can’t stretch the loops apart.


Well Field DonWell Field Don’’tstsPVC or Copper

BentoniteGrout

•Don’t use vaults•Don’t require cross trenching•Always use reverse return or close headers•Don’t use Pure Bentonite Grout•Put wells any closer than 20’ OC.


Improving System EfficiencyImproving System Efficiency

A well designed unitary approach fills the bill For short run, low pressure loss air distribution.


Is variable frequency performance Is variable frequency performance linear?linear?

Does inverter efficiency remain at a constant Does inverter efficiency remain at a constant 90+% efficiency over the range of control?90+% efficiency over the range of control?Is the additional complexity of Inverter logic Is the additional complexity of Inverter logic worth it?worth it?Due to Static pressure control do we ever gain Due to Static pressure control do we ever gain on system Efficiency?on system Efficiency?Is there another way?Is there another way?


Variable Frequency Drive Variable Frequency Drive PerformancePerformance

Source:ASHRAE ResearchNY 08-044Dr. Sally McInerny

INVERTER EFFICIENCY

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 10 20 30 40 50 60 70 80 90 100

LOAD

INPU

T EF

FICE

INCY 1

5

10

25

100


Parallel Pump CurveParallel Pump Curve

Parallel pump operating point3.1 HP (3.8 HP/100 tons)

Individual pump operating point1.75HP (2.1 HP/100 tons)

Single pump and Parallel pump operation allows for greatly reduced pump horsepower usage during normal operation. No speed control is required.

200 gpm @ 40’ Parallel Pumps165 gpm @27’ Single pump


One Pipe System AdvantagesOne Pipe System Advantages

Primary pumps can be sized to match block load instead of Primary pumps can be sized to match block load instead of equipment flow requirements.equipment flow requirements.System energy usage is directly connected to system load and System energy usage is directly connected to system load and equipment demand without variable flow controls.equipment demand without variable flow controls.Low primary flow system headLow primary flow system head

Reduced piping length (Lower first cost)Reduced piping length (Lower first cost)Reduced piping system complexityReduced piping system complexity

Single Pipe Technology

P PESimply Efficient

1


Normal Schools Renovation Project Normal Schools Renovation Project RequirementsRequirements

Provide space cooling at no additional operating cost to the Provide space cooling at no additional operating cost to the Owner vs. heating only application.Owner vs. heating only application.Individual classroom temperature controlIndividual classroom temperature controlIndividual classroom ventilation controlIndividual classroom ventilation controlEasily maintained systemsEasily maintained systemsNO DDC controlNO DDC controlComply with ASHRAE and IBC standards Comply with ASHRAE and IBC standards Project Budget $16.00 Project Budget $16.00 -- $18.00/ ft^2$18.00/ ft^2

$ $ $ $


Initial ConditionInitial Condition


Existing SystemExisting System

Room mounted heating only unit ventilatorsRoom mounted heating only unit ventilatorsExcessive fan noiseExcessive fan noisePrevious piping system repair replaced under floor system Previous piping system repair replaced under floor system with with ““in roomin room”” mounted distribution pipingmounted distribution piping


3 different mechanical rooms and boiler systems to correspond to building physical requirements.


New SystemNew System

New room by room New room by room vertical unit ventilatorsvertical unit ventilatorsQuiet design Quiet design Setback thermostats, Setback thermostats, integrated with lighting.integrated with lighting.Individual ventilation Individual ventilation dampersdampers


System DesignSystem Design

Pumping strategyPumping strategyParallel Primary Pumping based on thermal demandParallel Primary Pumping based on thermal demandPrimary Circulation pumps designed for 12Primary Circulation pumps designed for 12ººF, when F, when considering building considering building blockblock load.load.Unit by unit constant volume Unit by unit constant volume

Room Temperature controlRoom Temperature controlThermostat Control (space by space)Thermostat Control (space by space)Setback Interlocked with LightingSetback Interlocked with Lighting

Building DiversityBuilding DiversityPiping system offers space by space load diversityPiping system offers space by space load diversity


Mechanical / Electrical SystemsMechanical / Electrical Systems

Systems Systems cannotcannot impede learning impede learning New designs mustNew designs must

Minimize mechanical system noise Minimize mechanical system noise Provide Proper Temperature and Humidity ControlProvide Proper Temperature and Humidity ControlExhibit Poor Humidity ControlExhibit Poor Humidity ControlControl Particulate dispersion through the spaceControl Particulate dispersion through the spaceProvide appropriate ventilation/ oxygenationProvide appropriate ventilation/ oxygenationBe energy efficientBe energy efficientMust be adaptable to the changing educational Must be adaptable to the changing educational environmentenvironment

EducationEducation

Performance Innovation ExperiencePerformance Innovation Experience

Wxá|zÇ


Comparison04-05 to 06-07

Energy Usage – 37.3% Energy $ - 77% 206% increase in $/kbtuh

Oakdale Energy Use

0.0

100,000.0

200,000.0

300,000.0

400,000.0

500,000.0

600,000.0

700,000.0

800,000.0

Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May

Month

Ener

gy (K

btu)

04-05

05-06

06-07

07-08

Oakdale Energy Cost

$-

$0.0100

$0.0200

$0.0300

$0.0400

$0.0500

$0.0600


Month

$/kb

tu

04-05

05-06

06-07

07-08

Oakdale SchoolOakdale School-- Normal IllinoisNormal IllinoisSystem resultsSystem results

Total energy budgetInitial-59 kbtu/ft^2/yrAs renovated-28 kbtu/ft^2/yr


84


Repeatable ResultsRepeatable ResultsOakdale Energy Use

0.0

100,000.0

200,000.0

300,000.0

400,000.0

500,000.0

600,000.0

700,000.0

800,000.0


Month

Ener

gy(K

btu)

04-05

05-06

06-07

07-08

Glenn Energy Usage

0.0

50,000.0

100,000.0

150,000.0

200,000.0

250,000.0

300,000.0

350,000.0

400,000.0


Month

Ener

gy (K

btu)

04-05

05-06

06-07

07-08

Base electrical usage Carbon Equivalent Savings

510 tons/year

Oakdale School –Energy usage 28.1 KBTU/sq ft

Glenn School –Energy usage 27.9 KBTU/sq ft


88

Carbon Equivalent Savings510 Tons per Year


AEDG ResultsAEDG Results

54.4 kBTU/FT^2-yr


AEDG Results AEDG Results

59.8 kBTU/FT^2-yr


ConclusionsConclusions

Geothermal solutions offer low first cost solutions to energy Geothermal solutions offer low first cost solutions to energy efficiency.efficiency.Using a system where energy is recycled will result in substantiUsing a system where energy is recycled will result in substantial al primary source energy savings.primary source energy savings.It does not take sophisticated control systems to provide It does not take sophisticated control systems to provide superior comfort and energy efficiencysuperior comfort and energy efficiencyControl of lighting and plug loads represents a MAJOR area for Control of lighting and plug loads represents a MAJOR area for system load rightsizing.system load rightsizing.Ventilation, everyoneVentilation, everyone’’s whipping boy, presents an opportunity s whipping boy, presents an opportunity for space humidity control if properly managed.for space humidity control if properly managed.Apply sound thermodynamics and system design principals Apply sound thermodynamics and system design principals before falling on the control sword. An improperly designed before falling on the control sword. An improperly designed system will never be fixed with controls. system will never be fixed with controls.


The FutureThe Future

Active Chilled Beams

Energy recoveryventilation dehumidifier

15 cfm per person/.33 cfm/sq. ft./ 24 grains �G

Decoupling Humidity and Temperature Control


Questions?Questions?


Out of the Box WayOut of the Box Way(distributed primary secondary system)(distributed primary secondary system)

One pipe configuration allows primary pumps to be sized for block cooling and heating loads

TC

S1

S2

System flow is designed to provide 12ºF at the loop field.During part load, one primary circulating pump may be used Reducing system horsepower consumption significantly

12ºF

ashrae aedg k12.ppt [read-only] - ashrae® kansas …€¦ · · 2011-09-28poor hydronic...

Documents