Modeling To Inform Design

Modeling To Inform Design

INTEGRATED DESIGN PROCESSMODELING PROCEDURES

CASE STUDIES

IBPSA - USA

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Modeling Fundamentals

Performance Rating Method Best Practices Inform Design Measurement &

Verification

IBPSA - USAMODELING AND THE BUILDING LIFE CYCLE

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Verification

IBPSA - USA

Performance Impact

TimeProject Start

Project Finish

HIGH

LOWLevel of Effort

Leve

l of E

ffort

Typical energy modeling timeframe

EARLY DECISIONS ARE THE MOST IMPORTANT

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Verification

IBPSA - USAINTEGRATED DESIGN PROCESSTIME COMPARISON

Typical Integrated

Design Development

Construction Documents

Schematic Design

Construction AdminProject Closeout

Pre-design

Design Development


Schematic Design

Construction Admin

Pre-design

Project Closeout

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Verification

IBPSA - USAINTEGRATED DESIGN PROCESSOVERVIEW

• Align team around energy-related goals• Make design recommendations EARLY to increase potential for

impact• Identify where efforts should be focused to maximize energy

savings and equipment downsizing• Maximize opportunity for energy efficiency

Goal Setting Technical Potential

“Right Steps” Energy

Modeling

Activities

Modeling Objectives

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Verification

IBPSA - USAINTEGRATED DESIGN PROCESSGOAL SETTING

Use Energy Modeling to Quantify Targets

Types of GoalsOverall Target Values• EISA 2007• EUI < 35 kBtu/sf/yr• Net Zero operating carbon

• Demand < 3 W/sf

Comparative• 55% better than ASHRAE 90.1-2007

• Lowest EUI of any U.S. museum

• 80% water reduction from current use

Certifications• LEED Platinum• Energy Star score• ASHRAE Building Energy Quotient

• Living Building Challenge

End Use Specific• 80% reduction in lighting energy from natural daylight

• 100% of heating from waste heat and solar thermal

kBTU/sf/yr% reduction

below ASHRAE 90.1

No mechanical

coolingGoal Setting Charrette

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Verification

IBPSA - USAINTEGRATED DESIGN PROCESSTECHNICAL POTENTIAL

WHAT IS IT??The minimum level of energy consumption possible for a building, given today’s technology (excluding renewables).

HOW DO WE DETERMINE THIS?• Start with a baseline or current

design• Removes the losses and

inefficiencies with best available technology

WHY DO WE CARE?• Challenges conventional ways of thinking• Not limited by industry benchmarks/norms• Leads to more aggressive design targets• Explicitly determines where ground has

been lost

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Verification

IBPSA - USAINTEGRATED DESIGN PROCESSTHE RIGHT STEPS IN THE RIGHT ORDER

(1) Define Needs(2) Identify Appropriate Measures

(3) Reduce Loads(4) Select Appropriate & Efficient Technology

(5) Plan System Layouts(6) Optimize Operation

(7) Seek Synergies(8) Explore Alternative Power

Most people start here!

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Verification

IBPSA - USAINTEGRATIVE DESIGN PROCESSITERATIVE ANALYSIS PROCEDURE

Optimize Load Reduction Strategies

Resize and Reselect

Mechanical Equipment

Compare Metrics to Benchmarks

and Goals

Use LCCA to Evaluate Options

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Verification

IBPSA - USAINTEGRATIVE DESIGN PROCESSSUPPORTING THE BUSINESS CASE

• Include all cash flows• Identify “business as

usual” baseline

40,000 60,000 80,000 100,000 120,000 140,000 160,000

($20,000,000)

($10,000,000)

$0

$10,000,000

$20,000,000

$30,000,000

$40,000,000

NPV Mid

15-Year NPV of Package versus Cumulative CO2 Savings

Cumulative Metric Tons of CO2 Saved over 15 YearsNet P

rese

nt V

alue

of M

easu

res

Pack

age NPV

Max

NPV Neu-tral

Max CO2 Re-duction

• Packages of measures– Downsize HVAC equipment

• Identify packages that meet various goals

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Verification

IBPSA - USA

Evaluate heating and cooling load breakdowns to identify impactful load reduction measures….this is how you can downsize HVAC systems!

** Use “Design Day” Feature

Peak Cooling Load Contributions

Potential Cooling Load Reduction

INTEGRATIVE DESIGN PROCESSSUPPORTING THE BUSINESS CASE

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Verification

IBPSA - USA

Show a path to a desired goal – communicate to the owner/architect early on that this is important!

INTEGRATIVE DESIGN PROCESSSUPPORTING THE BUSINESS CASE

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Modeling to Inform Design

INTEGRATED DESIGN CASE STUDY:NELHA

IBPSA - USA

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IBPSA - USA

AIA Top 10 Green Projects-2007

NELHA CASE STUDYINTEGRATED HIGH PERFORMANCE BUILDING

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IBPSA - USA

Regenerative Design

Warm Air

Cool Air

Condensate waterfor irrigation

Warm air

Cool water

NELHA

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IBPSA - USA

Annual Energy Use: 8.6kBtu/sf

Annual Energy Cost Savings: $25,437

Indoor Potable Water Use: 11,700 gal/yr

Indoor Potable Water Use Reduction: 73%

Outdoor Potable Water Use: Zero

LEED NC V2.1 Platinum

Date Completed: November 2005

NELHA

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SUPPORTING THE BUSINESS CASE

CAR DEALERSHIP

IBPSA - USA

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IBPSA - USA

• Select “ripe” dealerships• Energy audits

Information Seeking

• Calibrated energy models• Define Business as Usual (BAU)• Brainstorm EEMs• Calculate operating cost savings and capital cost requirements

Analysis

• Create packages of measures• Downsize HVAC for each package & determine capital cost savings• Analyze LCC of packages• Create “recommended” package

LCCA

• Recost with local contractors and revise LCC numbers• Implement measures with local contractorsImplementation

CAR DEALERSHIP CASE STUDYLIFE CYCLE COST ANALYSIS

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IBPSA - USA

Hot & Humid

Winter Haven, FL

Space Cool-ing

17%

Fans7%

Exte-rior

Lights32%

Plug Loads

7%

Air Compressor

0.5%

Interior Lights37%

CAR DEALERSHIP CASE STUDYEND USE BREAKDOWNS

Space Cooling6%

Space Heating

34%

Hot Water0.2%

Fans5%

Exterior Lights23%

Plug Loads5%

Air Com-

pressor0%

Interior Lights26%

Cold

Chicago, IL19

IBPSA - USACAR DEALERSHIP CASE STUDYSUMMARY OF RESULTS

IMPACT OF Life Cycle Cost Analysis (LCCA)• Forced the dealers to consider metrics beyond SPP• Gave “credit” for downsizing HVAC• By considering integrated packages of measures, we were

able to “finance” measures with non-quantifiable benefits– Improved thermal comfort– Increased sales and worker productivity from daylighting

Estimated 53 – 80% operating cost

savings per pilot project

Average simple payback of 7.5

years

Dealers have chosen the most

aggressive package of measures

At least one dealer is attempting to

achieve (operating) carbon neutrality with on-site PV

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SUPPORTING THE BUSINESS CASE

EMPIRE STATE BUILDING

IBPSA - USA

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IBPSA - USAEMPIRE STATE BUILDING (ESB) APPLICATION OF TECHNICAL POTENTIAL

www.esbsustainability.com

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IBPSA - USAESB PRE-RETROFIT

Prior to 2008, the Empire State Building’s performance was average compared to most U.S. office buildings.

Annual utility costs: $11 million ($4/sq. ft.)

Annual CO2 emissions: 25,000 metric tons (22 lbs/sq. ft.)

Annual energy use: 88 kBtu/sq. ft.

Peak electric demand: 9.5 MW (3.8 W/sq. ft. inc. HVAC)

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IBPSA - USAESB PROCESS

Motivation of ESB Ownership: To demonstrate how to cost-effectively retrofit a large multi-tenant office building to inspire others to embark on whole-building retrofits.

8

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IBPSA - USA

Current Energy Use

Annu

al E

nerg

y Us

e

1

What is the maximum level of energy savings for this building given today’s technology?

ESB: TECHNICAL POTENTIAL EXERCISE

90 kBtu/sf/yr

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IBPSA - USA

Current Energy Use

Annu

al E

nerg

y Us

e

1EEMs

2


Cool

ing

Ener

gy U

se

RaiseCoolingSetpoint Envelope

& OA Savings

ReduceInternalGains Cooling

Efficiency

Cooling T-MinExisting

Cooling

65% Savings


90 kBtu/sf/yr

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IBPSA - USA

Current Energy Use

Annu

al E

nerg

y Us

e

1EEMs

2

Technical Potential

3

Constraints4

Implementable Minimum

5


90 kBtu/sf/yr


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IBPSA - USAESB: TECHNICAL POTENTIAL EXERCISE

Technical Potential: 30 kBtu/sf/yr

Baseline: 90 kBtu/sf/yr

67% Savings

29% not cost effective or

implementable

Implementable Minimum:

57 kBtu/sf/yr

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IBPSA - USAESB: IMPLEMENTABLE MINIMUM

Energy and CO2 savings result from 8 key projects.

Baselin

e

Balanc

e of D

DC

Tenan

t Day

/lighti

ng/Plug

s

VAV AHU's

Retrofi

t Chill

er Plan

t

Building

window

s

Tenan

t Ene

rgy M

gmt

Radiat

ive ba

rrier

Tenan

t DCV

Energy

Use0

100,000,000

200,000,000

300,000,000

9%6%

5% 5%5% 3% 3% 2%

Annual Energy Savings by Measure

Annu

al E

nerg

y Us

e (k

Btu)

38% Reduction

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IBPSA - USA

ESB SUMMARYEight integrated

efficiency measures

38% energy use reduction

CO2 emissions reduced by

105,000 metric tons

Peak cooling loads reduced by 33% (1600

tons)

Immediate and future

CapEx avoidance

Peak demand reduced by

3.5 MW

Cost saving

Enhanced work

environments

Improved worker

productivity

Green Certifications

Pursuing LEED Gold EB

EnergyStar score of 90

3030


MODELING PROCEDURES

IBPSA - USA

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Verification

IBPSA - USA

MODELING PROCEDURES

Pre Design

Schematic Design

Design Development


How is energy modeling best utilized during each phase?

What are the key steps to be followed during each phase?

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Verification

IBPSA - USAMODELING PROCEDURESPRE-DESIGN

Establish and align team around energy-savings goals

Use energy modeling “technical potential” analysis to drive goal setting

Perform modeling to inform early design decisions regarding: building siting and orientation, geometry, massing and program layout, passive strategies, glazing size and location, shading and daylighting strategies

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Erik Kolderup

Notes were not for this slide and have been deleted.



Verification

IBPSA - USAMODELING PROCEDURESPRE-DESIGNConfirm critical assumptions and big picture analysis• Take what you know (footprint, building type, etc) and construct

a 90.1-2007 model• Document all assumptions, note values to be validated• Evaluate the end-use breakdown to identify major savings

opportunities• Evaluate peak heating and cooling load contributions to identify

ways to downsize mechanical systems• Analyze certain measures that are early design decisions and

will be difficult to change later• Determine the “technical potential” for reduced energy

consumption to challenge the actual design34



Verification

IBPSA - USAMODELING PROCEDURESSCHEMATIC DESIGN

Be timely• Decision-making can happen quickly. If modeling is time constrained,

consider simplifying schedules, spaces/HVAC zones and window geometry. Recommendations made based on a targeted, simplified analysis are better than no recommendations.

Address design components that are laid-out and decided-upon in SDs• Low pressure-drop system design with energy recovery• Floor-to-floor height and space layout to maximize daylight-use potential• Integrated systems – UFAD, natural ventilation, mixed-mode ventilation

Respond to and leverage the project specifics• Client motivations• Design team need for information• The project story

35

Erik Kolderup

Notes could be updated. They correspond to an earlier version of this slide.



Verification

IBPSA - USAMODELING PROCEDURESSCHEMATIC DESIGN• Review all available documents (Owner’s Requirements, Narratives,

Drawings). Extract known data, document assumptions.• Compile schedules, LPD, EPD design data for team to review, get info

for ASHRAE fan power calculation (filters, sound attenuation, etc.)• Evaluate those things that can’t be modeled with alternative methods

(e.g. thermodynamic equivalent, spreadsheet, 8760 schedule, etc.)• Evaluate impact of change from “reference” to “technical potential”• Define several HVAC alternatives• Expand EEMs to include synergistic elements• Make series of runs that include one EEM at a time to facilitate QC • Define packages to cover range of targets• Check results against metrics (site, plant, end-use) and targets

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Erik Kolderup




Verification

IBPSA - USAMODELING PROCEDURESDESIGN DEVELOPMENT

Right-sizing of systems• Size most systems to just meet design loads• Over-sizing (typically systems with VFDs): allow room for

expansion, and benefit from improved efficiencies at part load

Inform value engineering decisions• Convey the cumulative impact of efficiency measures• Analyze the impact of value engineering options

Inform the design relative to fine-tuning of efficiency strategies• Controls: Staging / delta T / resets / VAV minimums / etc.• Shading characteristics – width of overhangs / fins, etc.

37

Erik Kolderup

Notes could be updated. Correpond to an earlier version of this slide.



Verification

IBPSA - USAMODELING PROCEDURESDESIGN DEVELOPMENT

• Update model input with latest design info, document assumptions• Identify any gaps in the plans & specifications (e.g. fenestration properties, fan

bhp, sequence of operations, etc.) and request clarifications. • For lifecycle cost analysis or value engineering, identify efficiency measures

already incorporated into the design, and use parametric cases to show performance without these measures

• Identify and analyze efficiency measures not analyzed in earlier phases• Fine-tune efficiency measures in design

• control parameters• exterior shade depths • chiller selection (using part-load curves)

• Verify equipment capacities will meet comfort conditions without jeopardizing energy efficiency

38

Erik Kolderup




Verification

IBPSA - USAMODELING PROCEDURESCONSTRUCTION DOCUMENTS

Ensure project efficiency strategies remain in the building design

Finalize Performance and Savings Estimates

Document savings for LEED / EPACT / other

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Verification

IBPSA - USAMODELING PROCEDURESCONSTRUCTION DOCUMENTS• Check for changes to building form, orientation, or thermal zones• Verify envelope input parameters• Identify any changes to LPD, EPD, or schedules• Identify any changes to fan bhp, air flow, and other HVAC equipment• Identify any changes to controls• Revise model to reflect current design• Check results against DD results, metrics, targets• Ensure that documentation appropriately responds to information

requested by Authority Having Jurisdiction• Provide full justification for all savings claimed• Provide a narrative justifying any non-standard inputs or outputs

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Erik Kolderup




Verification

IBPSA - USACONSTRUCTION DOCUMENTS LEED SUBMITTAL REQUIREMENTS

Input Summary

• Identify each major Baseline and Proposed Case Input. Examples: • R-13+R3.8ci steel-

framed walls, U-0.064

• Supply temperature reset based on worst case zone between 55 deg. F & 60 deg. F

• Identify where exceptions have been taken (e.g. system type exceptions, no Energy recovery modeled for 100% OSA system, etc.)

Output Summary

• Enter energy consumption by end-use

• Enter peak demand by end-use (for month with highest peak demand)

• Enter energy cost by energy type

Renewable / Exceptional Calculations

• Renewable Calculations• EAc2: full

explanation of calcs• Explain variations

between virtual energy cost for energy model and average energy cost offset by renewables

• Exceptional Calculations• Provide detailed

narrative with justification for all assumptions made

• Provide a copy of studies used

• Provide calculations

Backup documents

• Simulation output summary reports• Energy consumption

by end-use• Energy cost by

energy type• Unmet load hours• Envelope summary

• Simulation input summary reports• Envelope• Sample system• Sample thermal

zone• Mechanical Schedule

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CONSTRUCTION DOCUMENTS CASE STUDY

UH C-MORE LAB

IBPSA - USA

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IBPSA - USAUH C-MORE CASE STUDYCONSTRUCTION DOCUMENTATION REVIEWS

Goal of CD Reviews: To ensure inclusion of all sustainability measures and LEED points.

CD Energy Modeling: Completion of Exceptional Calculation Measures.

52% energy savings

31% energy cost

savings

Pursuing LEED Gold

ASHRAE 90.1-2004

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IBPSA - USA

Error in Lab ACH Turndown

4% energy cost savings

1-2 LEED EAc1* points

Recommended SAT reset with

humidity controls

5% energy cost savings

1-2 LEED EAc1 points

No OA measuring

devices shown on drawings

IEQ c1*

UH C-MORE CASE STUDYCD REVIEW

*EAc1 Optimize Energy Performance**IEQc1 Outdoor Air Delivery Monitoring

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IBPSA - USA

Energy Savings

Operating Cost

Savings

LEED EAc1 Points

Without ECM 29% 19% 3

With ECM 52% 31% 6

Heat Recovery Schematic

Tank T=140F

Heat Pump

COP=2.8

Boiler η=0.82

Chiller

AHU Loads from

eQUEST

Coil Loads

from eQUEST

Losses

UH C-MORE CASE STUDYEXCEPTIONAL CALCULATION METHOD

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Modeling To Inform Design

Documents

design changes

design levels

concept design

later design phases

early design phases

typical design process

section modeling

project team