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Modeling To Inform Design. IBPSA - USA. Integrated Design Process Modeling Procedures Case Studies. 1. Modeling and the Building Life Cycle. 2. Performance Impact. Level of Effort. Early Decisions Are The Most Important. Typical energy modeling timeframe. HIGH. Level of Effort. - PowerPoint PPT Presentation
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Modeling To Inform Design
INTEGRATED DESIGN PROCESSMODELING PROCEDURES
CASE STUDIES
IBPSA - USA
1
Modeling Fundamentals
Performance Rating Method Best Practices Inform Design Measurement &
Verification
IBPSA - USAMODELING AND THE BUILDING LIFE CYCLE
2
Modeling Fundamentals
Performance Rating Method Best Practices Inform Design Measurement &
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
3
Modeling Fundamentals
Performance Rating Method Best Practices Inform Design Measurement &
Verification
IBPSA - USAINTEGRATED DESIGN PROCESSTIME COMPARISON
Typical Integrated
Design Development
Construction Documents
Schematic Design
Construction AdminProject Closeout
Pre-design
Design Development
Construction Documents
Schematic Design
Construction Admin
Pre-design
Project Closeout
4
Modeling Fundamentals
Performance Rating Method Best Practices Inform Design Measurement &
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
5
Modeling Fundamentals
Performance Rating Method Best Practices Inform Design Measurement &
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
6
Modeling Fundamentals
Performance Rating Method Best Practices Inform Design Measurement &
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
7
Modeling Fundamentals
Performance Rating Method Best Practices Inform Design Measurement &
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!
8
Modeling Fundamentals
Performance Rating Method Best Practices Inform Design Measurement &
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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Modeling Fundamentals
Performance Rating Method Best Practices Inform Design Measurement &
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
10
Modeling Fundamentals
Performance Rating Method Best Practices Inform Design Measurement &
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
11
Modeling Fundamentals
Performance Rating Method Best Practices Inform Design Measurement &
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
13
IBPSA - USA
AIA Top 10 Green Projects-2007
NELHA CASE STUDYINTEGRATED HIGH PERFORMANCE BUILDING
14
IBPSA - USA
Regenerative Design
Warm Air
Cool Air
Condensate waterfor irrigation
Warm air
Cool water
NELHA
15
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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Modeling to Inform Design
SUPPORTING THE BUSINESS CASE
CAR DEALERSHIP
IBPSA - USA
17
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
18
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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Modeling to Inform Design
SUPPORTING THE BUSINESS CASE
EMPIRE STATE BUILDING
IBPSA - USA
21
IBPSA - USAEMPIRE STATE BUILDING (ESB) APPLICATION OF TECHNICAL POTENTIAL
www.esbsustainability.com
22 22
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
24
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
25
IBPSA - USA
Current Energy Use
Annu
al E
nerg
y Us
e
1EEMs
2
What is the maximum level of energy savings for this building given today’s technology?
Cool
ing
Ener
gy U
se
RaiseCoolingSetpoint Envelope
& OA Savings
ReduceInternalGains Cooling
Efficiency
Cooling T-MinExisting
Cooling
65% Savings
ESB: TECHNICAL POTENTIAL EXERCISE
90 kBtu/sf/yr
26
IBPSA - USA
Current Energy Use
Annu
al E
nerg
y Us
e
1EEMs
2
Technical Potential
3
Constraints4
Implementable Minimum
5
What is the maximum level of energy savings for this building given today’s technology?
90 kBtu/sf/yr
ESB: TECHNICAL POTENTIAL EXERCISE
27
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
29
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 to Inform Design
MODELING PROCEDURES
IBPSA - USA
31
Modeling Fundamentals
Performance Rating Method Best Practices Inform Design Measurement &
Verification
IBPSA - USA
MODELING PROCEDURES
Pre Design
Schematic Design
Design Development
Construction Documents
How is energy modeling best utilized during each phase?
What are the key steps to be followed during each phase?
32
Modeling Fundamentals
Performance Rating Method Best Practices Inform Design Measurement &
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
33
Modeling Fundamentals
Performance Rating Method Best Practices Inform Design Measurement &
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
Modeling Fundamentals
Performance Rating Method Best Practices Inform Design Measurement &
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
Modeling Fundamentals
Performance Rating Method Best Practices Inform Design Measurement &
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
36
Modeling Fundamentals
Performance Rating Method Best Practices Inform Design Measurement &
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
Modeling Fundamentals
Performance Rating Method Best Practices Inform Design Measurement &
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
Modeling Fundamentals
Performance Rating Method Best Practices Inform Design Measurement &
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
39
Modeling Fundamentals
Performance Rating Method Best Practices Inform Design Measurement &
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
40
Modeling Fundamentals
Performance Rating Method Best Practices Inform Design Measurement &
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
41
Modeling to Inform Design
CONSTRUCTION DOCUMENTS CASE STUDY
UH C-MORE LAB
IBPSA - USA
42
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
43
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
44
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
45
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