GSB Library Atrium AnalysisKnight Management Building
John BrooksRichard JonesReid SenescuMin Jae SuhMatt Yamasaki
GSB Library Atrium Building AnalysisKnight Management Center
GSB Library Atrium AnalysisKnight Management Building
Options
Base
No Basement Skylights
Alternate
Basement Skylights
GSB Library Atrium AnalysisKnight Management Building
Options
Base
No Basement Skylights
Alternate
Basement Skylights
GSB Library Atrium AnalysisKnight Management Building
Potential Advantages of SkylightPlus Minus
Structure None expected Other beams bigger.Larger lateral deflections.More complex gravity framing
Energy More natural ventilation, less cooling load
Bigger temp. difference between bottom and top of libraryLess insulation, could create more heating/cooling load
Lighting More daylighting, .less energy Potential glare, sunshine on books
Acoustics None expected Louder, more sound absorbing material
CFD Nat. Ventilation better in the summer
Airflow from doors could decrease comfort in winter
Cost Lower life cycle cost Higher first cost, because of less homogenous design
Schedule None expected Added scope, longer duration
GSB Library Atrium AnalysisKnight Management Building
Outline
1. Goals and Preferences2. Structure 3. Lighting4. Acoustics5. Cost6. Schedule, 4D7. Energy Analysis8. CFD9. Value Summary10. Decision
For each tool:a) Inputsb) Assumptionsc) Metricsd) Resultse) Confidencef) Comparison
GSB Library Atrium AnalysisKnight Management Building
StructureETABS
Revit Structure 2008
GSB Library Atrium AnalysisKnight Management Building
Process• Begin with Revit model • Export exr file via CSIxRevit2008• Import files to ETABS• Correct geometry, rebuild moment frame,
establish foundation conditions.• Assign loading conditions• Generate deflection and moment conditions
– Screenshots to PPT
• Evaluate performance (deflections)• Evaluate efficiency (lb of steel/sf)
GSB Library Atrium AnalysisKnight Management Building
Assumptions• Default Static Loads
– Dead– Live – Wind
• 3 Types of Quake Analysis– Recreated ARUP user defined loads.– IBC 2006 Defaults.– IBC 2006 matching spectral acceleration to USGS
data.
GSB Library Atrium AnalysisKnight Management Building
Baseline Structural System
Y Direction: Braced FrameX Direction: Moment Frame
Baseline Moment Frame
GSB Library Atrium AnalysisKnight Management Building
Framing ChangesRevit
Structural framing changes made in Revit to allow for exchange with Building Explorer
GSB Library Atrium AnalysisKnight Management Building
MomentsOriginal Atrium
Revised Atrium
Virtually Identical
GSB Library Atrium AnalysisKnight Management Building
Deflections
GSB Library Atrium AnalysisKnight Management Building
Design Check
GSB Library Atrium AnalysisKnight Management Building
Efficiency CheckRevit
Original Structure Revised Structure
Family and Type Count Volume Units Count Volume Units
W16 303 319.11 cf 297 308.53 cf
W18 70 106.61 cf
W21 2 5.24 cf 2 5.24 cf
W24 94 213.41 cf 106 242.28 cf
HSS-BRB 30 37.18 cf 30 37.39 cf
Steel Volume 681.55 cf 593.44 cf
Weight of Steel 306,698 lb 267,048 lb
Building Area 44,220 sf 44,220 sf
Efficiency 6.94 lb/sf 6.04 lb/sf
GSB Library Atrium AnalysisKnight Management Building
Structure – MetricsGoal Metric Preference Criteria
-3 0 3
Direct Metrics
Use Materials Responsibly
Weight of Steel 3.4 +10 lb/sf 7 lb/sf
5 lb/sf
Minimize Liability
Deflections 3.0 >5.0 3.0 <1.0
Dependent Metrics
First Cost $
GSB Library Atrium AnalysisKnight Management Building
ConfidenceTotal Sub process Effectiveness:• 30% Confident in information transfer:
– Transfer between Revit and ETABS is error prone. • 20% Confident in accuracy of results:
– Worked through several pages of error messages over numerous iterations. Made substantial improvements in consistency of results. Still not completely confident about all inputs.
– Increased efficiency appears to be excessive relative to the framing changes made.
– Getting steel quantities from ETABS would be preferable.
GSB Library Atrium AnalysisKnight Management Building
Day LightDaySim
GSB Library Atrium AnalysisKnight Management Building
Lighting - Assumptions• Occupied 10 AM to 12 AM• Min. Illuminance: 300 lux• Active and Passive light switching and blind use• Motion and Daylight Sensors• Installed lighting power density 1.5 W/SF
GSB Library Atrium AnalysisKnight Management Building
Lighting – MetricsGoal Metric Preference Criteria
-3 0 3
Direct Metrics
Be Beautiful Spatial Quality of Interior Areas
4.0 Claustro-phobic
OK Beautiful
Provide Good Light
Cont. Daylight Autonomy >10%
4.8 0 0 60
Dependent Metrics
Minimize Operation Cost
Energy Cost Per sf / Yr 4.4 2 1.54 1.1
Minimize Net Energy Use
Energy Consumption / Yr 5.6 >2500 2000 1000
GSB Library Atrium AnalysisKnight Management Building
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Skylights provide more light…Annual Light Exposure (lux hours)
Base
No Basement Skylights
Alternate
Basement Skylights
GSB Library Atrium AnalysisKnight Management Building
Not much direct light…
Alternate
Basement Skylights
December 21, 2008, 2:00 PM
GSB Library Atrium AnalysisKnight Management Building
ConfidenceTotal Sub process Effectiveness:• 100% Confident in information transfer accuracy:
– Performed thorough verification of material transfer– Geometry transferred accurately as .dwg
• 75% Confident in results accuracy:– Architect did not assign materials thoughtfully in Revit– No way of verifying intended material and true material properties– Revit rendering tools (especially animation) seem overly simplistic
GSB Library Atrium AnalysisKnight Management Building
Alternate Provides More ValueGoal Metric Base Alternate
Prediction Score Prediction Score
Be Beautiful Spatial Quality of Interior Areas
Dark -2 Nice 1
Provide Good Light DAcon >10% (%) 0 0 24 1
Day Lighting Value -8 8.8
Minimize Operation Cost
Energy Cost Per Square Foot / Yr
$1049 N/A $968 N/A
Minimize Net Energy Use
Energy Consumption / Yr
7550 kwh N/A 6970 kwh N/A
GSB Library Atrium AnalysisKnight Management Building
AcousticsEcotect
GSB Library Atrium AnalysisKnight Management Building
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Information• Goal
What is the acoustic influence of 3 skylights on the 1st floor to the GSB Library?
• ModelsBaseline: Original GSB LibraryAlternate: GSB Library with 3 skylights
• ParameterTwo different volume(Base:11,289m³ vs. Alternate:13,815m³)Two different spots of speaker(Basement vs. 1st Floor)
• Expectative ValueAlternate model produces a longer Reverberation Time in the
two cases because of the bigger volume
GSB Library Atrium AnalysisKnight Management Building
Process• Put 3 Skylights to original• Simplify the Revit models with Revit
Architecture 2008• Convert .rvt file to .dxf file• Import .dxf file to ECOTECT 5.5• Design the process with NARRATOR• Refer to the Stakeholder Preference for
MACDAI
GSB Library Atrium AnalysisKnight Management Building
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Assumption• Material Condition (Fixed)
GSB Library Atrium AnalysisKnight Management Building
Assumption (Cont)• Sound Condition (Setup 1 speaker)
Baseline Model Alternate Model
1st
Floor
VS.
Basement
VS.
GSB Library Atrium AnalysisKnight Management Building
Assumption (Cont)• Sound influences only front half side of the building • Consider only Sabine Algorithm for Reverberation
Time• Consider Audible Speech Frequencies: 500Hz ~ 4KHz (http://squ1.org/wiki/Human_Ear)
• No influence from an outside weather and a noise• 200 Hard-back Chairs, 50% Occupancy
GSB Library Atrium AnalysisKnight Management Building
MetricsGoal Metric Preference Criteria
-3 0 3
Direct Metrics
Provide Acoustic
Performance
ReverberationTime (ms)
3.3 Over 7000ms
4000ms~
4999ms
Under 2000m
s
Dependent Metrics
Minimize Operation Cost
N/A
Minimize Net Energy Use
N/A
GSB Library Atrium AnalysisKnight Management Building
Base vs. Alternate• Sound Path (1st Floor)
BaselineAlternate
GSB Library Atrium AnalysisKnight Management Building
Base vs. Alternate (Cont)• Sound Path (Basement)
BaselineAlternate
GSB Library Atrium AnalysisKnight Management Building
Baseline500Hz~4KHz
Speech Audible Frequency
Base vs. Alternate (Cont)• 1st Floor RT
Alternate500Hz~4KHzSpeech Audible Frequency
GSB Library Atrium AnalysisKnight Management Building
Baseline500Hz~4KHz
Speech Audible Frequency
Base vs. Option (Cont)• Basement RT
Alternate500Hz~4KHzSpeech Audible Frequency
GSB Library Atrium AnalysisKnight Management Building
Conclusion• Sound Path
Skylights allow the intrusiveness to each floor, but little.
• Reverberation Time Accept Requirement
*Library RT Criteria: Under 2sec (2000ms) (Acoustical considerations in planning and design of library facilities, Denelle&John, Vol 17 No.4, 1999)
All RTs are over the requirement for a library.
Baseline Alternate
1st Floor 2250ms ( )Ⅹ 2525ms ( )Ⅹ
Basement 10040ms ( )Ⅹ 9540ms ( )Ⅹ
Average 6144ms ( )Ⅹ 6034ms ( )Ⅹ
GSB Library Atrium AnalysisKnight Management Building
Recommendation• Changing the materials to sound-absorbing materials in the basement for reducing sound reflecting Ex. Acoustical tile ceiling, Carpets,
Fiberglass panels, Fabric wrapped etc.
• Avoiding on parallel walls with sound reflecting surfaces Ex. One wall of the room is glass, the wall opposite should have a sound-absorptive treatment
GSB Library Atrium AnalysisKnight Management Building
Confidence• Total Sub process Effectiveness:
100% Confident in information transfer accuracy:– Geometry transferred accurately as .dwg– Performed thorough verification of material transfer
70% Confident in results accuracy:– Architect did not assign materials thoughtfully in Revit– Demolish some structure components in Revit– Material library is short to assign in Ecotect– No way of verifying intended material and true material properties– A noise might replace a speaker as people’s voice– Average reverberation time calculates for the MACDADI result
GSB Library Atrium AnalysisKnight Management Building
Baseline & Alternate Same Value
Goal Metric Base Alternate
Prediction Score Prediction Score
Provide Acoustic Performance
ReverberationTime (ms)
6000ms~6999ms
-2 6000ms~6999ms
-2
Acoustics Value -6.6 -6.6
GSB Library Atrium AnalysisKnight Management Building
Cost and Schedule, 4DBuilding Explorer
GSB Library Atrium AnalysisKnight Management Building
Process• Begin with Revitt model • Export database, ifc, scene file
– Assign assemblies to each component in bldngs
• Import files to Building Explorer• Verify Components/Assemblies• Assign geographical location• Produce Schedule• Produce Estimate• Screenshots to PPT…
GSB Library Atrium AnalysisKnight Management Building
Assumptions• BE RS Means Database Cost Info Correct
– Had to substitute a few assemblies
• BE Assembly Sequencing Correct– Distributes floor-wise, however structural members
have weird sequencing– Structural, slabs, walls, roof, interior, equipment
GSB Library Atrium AnalysisKnight Management Building
Baseline System
Baseline Structural System Baseline Architectural Model -few structural members
GSB Library Atrium AnalysisKnight Management Building
Baseline Architectural Costs
GSB Library Atrium AnalysisKnight Management Building
Baseline Structural Costs
GSB Library Atrium AnalysisKnight Management Building
Baseline Architectural ScheduleArchitectural Model
GSB Library Atrium AnalysisKnight Management Building
Baseline Structural Schedule
GSB Library Atrium AnalysisKnight Management Building
Baseline 4D Models
Baseline Arch 4D
Baseline Struct 4D
GSB Library Atrium AnalysisKnight Management Building
Alternate System
Baseline Structural System Baseline Architectural Model -few structural members
GSB Library Atrium AnalysisKnight Management Building
Alternate Architectural Costs
GSB Library Atrium AnalysisKnight Management Building
Alternate Structural Costs
GSB Library Atrium AnalysisKnight Management Building
Alternate Architectural ScheduleArchitectural Model
GSB Library Atrium AnalysisKnight Management Building
Alternate Structural Schedule
GSB Library Atrium AnalysisKnight Management Building
Alternate 4D Models
Baseline Arch 4D
Baseline Struct 4D
GSB Library Atrium AnalysisKnight Management Building
Summary• Baseline
– Arch Cost: $5,090,875.99– Struct Cost: $181,312.92 – Arch Duration: 308– Struct Duration: 23
• Alternate– Arch Cost: $5,784,021.25– Struct Cost: $216,957.11– Arch Duration: 340– Struct Duration: 28
~10% INCREASE
GSB Library Atrium AnalysisKnight Management Building
Metrics
Analysis Goal Metric -3 0 3
Cost/SchedMinimize First Cost $/sqft 195 148 0
Minimize Schedule Duratin days 548 365 0
Base Cost 0Alt Cost 0
Base Sched -1Alt Sched -1
score
GSB Library Atrium AnalysisKnight Management Building
Confidence
• Total sub process effectiveness:– 85% confident in information transfer
accuracy• Assembly database missing a few components
– Had to find something comparable
– 95% confident in results accuracy• For what was entered results seemed to be
accurate
GSB Library Atrium AnalysisKnight Management Building
Energy and CFDIES
GSB Library Atrium AnalysisKnight Management Building
Energy Analysis• Goal:
– To determine operating cost of building– To determine energy consumption of building– To determine environmental impact of building
GSB Library Atrium AnalysisKnight Management Building
Energy Analysis• Assumptions:
– Model inputs• HVAC System: Mixed System w/ natural ventilation
– VAV as main system– Natural Ventilation as auxiliary system.
• Weather file: Moffett Field, Mountain View, CA• Building type: Library• Building construction: Educational
– Code regulated floor and roof– Low-e double glazed windows and atrium glass
• Thermal condition: Atrium Each Floor– Fluorescent lighting – 1.5W/SF– People 65 from 10am-12am– Computers – 0.929W/SF– Miscellaneous – 1W/SF– Air exchanges:
» Base case: Natural ventilation – 1 ach, Infiltration: 0.167 ach» Alternative Case: Natural ventilation – 1 ach, infiltration – 0.25 ach
– Simulation• Run period: 1 Jan to 31 Dec• Time step: 10 minutes• Report interval: 60 minutes• Preconditioning: 10 days
GSB Library Atrium AnalysisKnight Management Building
Energy Analysis Metrics• Benchmarks (Office building)
– Energy cost: Northern CA average of $1.54– Energy usage: National average of 2000 MMBtu– CO2 emissions: West Coast average of 20lb/sf
Analysis Goal Metric Preference -3 0 3
Energy
Minimize Operation Cost Energy Cost Per sf / Yr 4.4 2 1.54 1.1
Minimize Net Energy Use Energy Consumption / Yr 5.6 >2500 2000 1000
Exhibit Environmental Sustainability Annual CO2 Emissions per sf 4.2 >30 20 0
GSB Library Atrium AnalysisKnight Management Building
Energy Analysis Results• Energy consumption:
– Base case: 2402.4MMBtu
– Alternative case: 2470.1MMBtu
Alternative case energy consumption
Base case energy consumption
GSB Library Atrium AnalysisKnight Management Building
Energy Analysis Results• CO2 Emissions
– Base Case: 601,404lb/yr– Alternative:– 636,976lb/yr
Base Case CO2 Emissions
Alternative Case CO2 Emissions
GSB Library Atrium AnalysisKnight Management Building
Energy Analysis Results• Heating/Cooling Loads
– Base Case:• 276.4MMBtu – heating• 661.5MMBtu – cooling
– Alternative Case:• 188.3MMBtu – heating• 1096.7MMBtu – cooling
Base Case Cooling Loads
Alternative Cooling Loads
GSB Library Atrium AnalysisKnight Management Building
Energy Analysis Results• Comparison Charts
Energy Cost
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
Jan01-31
Feb01-28
Mar01-31
Apr01-30
May01-31
Jun01-30
Jul01-31
Aug01-31
Sep01-30
Oct01-31
Nov01-30
Dec01-31
Month
Co
st
($)
Base Case
Alternative Case
CO2 Emissions
0
10000
20000
30000
40000
50000
60000
70000
Month
lbC
O2
Base Case
Alternative Case
Total Energy Usage
0
50
100
150
200
250
300
Month
En
erg
y (
MM
Btu
)
Base Case
Alternative Case
GSB Library Atrium AnalysisKnight Management Building
Energy Analysis - Confidence• Total sub process effectiveness:
– 90% confident in information transfer accuracy• Geometry transferred accurately• Room data transferred accurately• Unsure about atrium/open spaces
– 60% Confident in results accuracy• Had to build new model from scratch• Inconsistencies in program• Assumptions blackbox
GSB Library Atrium AnalysisKnight Management Building
Energy Analysis – Value Comparison
• Base Case provides more value
Goal
Metric
Base Alternative
Prediction Score Prediction Score
Minimize Operation Cost Energy Cost Per Square Foot / Yr 2.06 -3.00 2.17 -3.00
Minimize Net Energy Use Energy Consumption / Yr 2402 -1.67 2470 -1.90
Exhibit Environmental Sustainability Annual CO2 Emissions 13.6 1.28 14.4 1.12
Value -17.176 -19.136
GSB Library Atrium AnalysisKnight Management Building
CFD Analysis• Goals:
– Determine occupant comfort– Determine thermal condition of room affected by
alteration
GSB Library Atrium AnalysisKnight Management Building
CFD Analysis• Process
– Run ApacheSim to get MacroFlo parameters• Problem: Geometry translation• Solution: Necessary output found in ApacheSim
GSB Library Atrium AnalysisKnight Management Building
CFD Analysis - Metrics• Benchmark:
– IES<VE> Comfort Indices• 1 – unbearably cold• 7 – perfectly comfortable• 15 – unbearably hot
– Mean percentage of people dissatisfied• Subjective benchmark
– Predicted mean Vote• 0 – neutral• -3 – cold• +3 - hot
GSB Library Atrium AnalysisKnight Management Building
CFD Analysis - Metrics• Metrics
Analysis Goal Metric Preference -3 0 3
CFD
Provide Thermal Comfort Percentage of people dissatisfied 3.6 75% 20% 5%
Provide Thermal Comfort Predicted Mean Vote 3.6 3,-3 1,-1 0
Provide Thermal Comfort Comfort Index 3.6 1,13-15 4,10 7
GSB Library Atrium AnalysisKnight Management Building
CFD Analysis - Results• Base Case:
– Percentage dissatisfied:• Max: 28%• Min: 5%• Mean: 10%
– Predicted Mean Vote:• Max: 1.04• Min: -0.23• Mean: 0.35
– Comfort Index:• Max: 10• Min: 6• Mean: 8
• Alternative Case:– Percentage dissatisfied:
• Max: 28%• Min: 5%• Mean: 10%
– Predicted Mean Vote• Max: 1.04• Min: -0.23• Mean: 0.38
– Comfort Index:• Max: 10• Min: 6• Mean: 8
GSB Library Atrium AnalysisKnight Management Building
CFD Analysis• Graphical
Representation of results
Percentage of dissatisfied occupants
Predicted Mean Vote
GSB Library Atrium AnalysisKnight Management Building
CFD Analysis• Stacks study room thermal analysis
– Peak room loads
– Room conditions: Occupied
– Whole day
Room NameTemperature (°F) Relative Humidity (%) PPD (%)
Max Min Max Min Max Min
Base 75 64 70.5 25.7 16.8 5
Alternative 75 64 70.5 25.7 16.6 6
Room Name
Peak Room Conditioning Loads (Btu/h)Internal
*Cooling ChecksGains
Sensible Sensible Humidi- Dehumidi- (Btu/h)(Btu/h·ft²) (cfm/ft²)
Heating Cooling fication fication
Base 24790 26658 3147 8229 35948 5.42 0.35
Alternative 23401 28680 3145 8229 35948 5.83 0.38
Room NameTemperature (°F) Relative Humidity (%) PPD (%)
Max Min Max Min Max Min
18 Room 75 64 76.9 22.2 19.4 5
18 Room 75 64 76.8 22.2 19.3 5
GSB Library Atrium AnalysisKnight Management Building
CFD Analysis Confidence• Total sub process effectiveness:
– 0% confident in information transfer accuracy• No errors in geometry transfer• Still finds “external” holes in building even though new
model created– 60% confident in results accuracy
• “Blackbox” effect• Unsure how program treats atrium/open spaces
GSB Library Atrium AnalysisKnight Management Building
CFD – Value Comparison• Base case provides more value
Goal
Metric
Base Alternative
Prediction Score Prediction Score
Provide Thermal Comfort Percentage of people dissatisfied 10 2.00 10 2.00
Provide Thermal Comfort Predicted Mean Vote 0.35 1.60 0.38 1.48
Provide Thermal Comfort Comfort Index 8 2.00 8 2.00
Value 20.16 19.73
GSB Library Atrium AnalysisKnight Management Building
Options are close…..
Base – No Basement Skylights Alternate – Basement Skylights
-0.3 Weighted Value .07 Weighted Value
GSB Library Atrium AnalysisKnight Management Building
Include Skylights
Alternate – Basement Skylights
.07 Weighted Value