The Science Behind DIVA - Solemma · DIVA DAY – Oct 19th 2012 Energy Considerations The Science...
Transcript of The Science Behind DIVA - Solemma · DIVA DAY – Oct 19th 2012 Energy Considerations The Science...
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Christoph ReinhartDIVA DAY – Oct 19th 2012Christoph ReinhartDIVA DAY – Oct 19th 2012
Energy Considerations
The Science Behind DIVAAnd how to present it to your clients
Visualization Daylighting Metrics Annual Glare Maps
Operational EnergyPoint in Time GlareRadiation Map
DIVA ApproachDIVA links validated performance simulation engines to Rhino and thusgives users access to meaningful, actionable data from the beginning of aproject. We believe this early integration empowers creative,consequential, and lasting design interventions.
Radiation MapsRadiation MapsClimate‐based MetricsClimate‐based MetricsVisual ComfortVisual ComfortRadianceRadiance
Rhino ModelRhino Model
Annual Glare MapsAnnual Glare Maps Thermal LoadsThermal LoadsVisualizationsVisualizationsEvalglalreEvalglalre DaysimDaysim GenCumulativeSkyGenCumulativeSky DaysimDaysim EnergyPlusEnergyPlus
GrasshopperGrasshopper
DIVA links validated performance simulation engines to Rhino and thusgives users access to meaningful, actionable data from the beginning of aproject. We believe this early integration empowers creative,consequential, and lasting design interventions.
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BPS TodayBuilding Performance Simulation: An computer-based attempt to model the various energy and mass flows within a building in order to predict one or several performance aspects of a design.
Operational EnergyOperational Energy Solar RadiationSolar Radiation DaylightDaylight
Return on InvestmentReturn on Investment Occupant ComfortOccupant Comfort WalkabilityWalkability
BPS TodayA field in transition…
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DIVA’s specific focus areas are daylighting, glare, occupant comfort and operational energy use.
DIVA Approach to Daylighting
Figure from Daylighting Manual (Reinhart)
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What is the relationship between daylight availability and building massing, i.e. how much
of a building can be daylit depending on its overall shape and surrounding context?
Daylight Availability and the Daylit Area
Source Daylighting Manual (Reinhart)
How can we determine the daylit area in a space?
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Daylight Autonomy
Source Daylighting Manual (Reinhart)
Daylight autonomy (DA) is a daylight availability metric that corresponds to the percentage of the occupied time when the target illuminance at a point in a space is met by daylight.
According to the IESNA a point is ‘daylit’ if the Daylight Autonomy at 300 lux is above 50%.
We expect DA to be adopted by LEED and other Green building Standards.
Ok, that’s what the computer tells us.How well does daylight autonomy relate to
occupant assessments of spaces?
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Carpenter Center Study
Source Daylighting Manual (Reinhart)
C F Reinhart and D Weissman, "The Daylit Area - Correlating architectural student assessments with current and emerging daylight availability metrics", Building and Environment, 50, pp. 155-162, 2012.
Daylight Autonomy Comparison
Comparison for this one space encouraging.
Daylight Autonomy300lux[50%]
Mean Occupant Assessment
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dynamic interaction of light and building form
DA500lux[50%]
DA150lux[50%]
DA300lux[50%]
MIT (USA) Miami University (USA) Parsons (USA)
Iowa (USA) Paraiba (Brazil) UFSC (Brazil)
Concordia (Canada) Idaho (USA)
Ok, I am signed up for Daylight Autonomy. How can I calculate it?
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Significance of the Simulation EngineComparison of a Best Practice Model using Ecotect-Split-Flux vs. Radiance
Best Practice Model Ecotect
Mean Daylight Factor = 0.55%
Percentage of floor area >2% = 0%
Best Practice Model Radiance
Mean Daylight Factor = 2.59%
Percentage of floor area >2% = 42%
dramatic difference between both engines due to wall thicknessPaper: Ibarra D, Reinhart C F, "Daylight factor simulations - 'How close do simulation beginners 'really' get?“, Proceedings Building Simulation 2009
climate Data: i
Light. Res. & Technology Mardaljevic, 1995
Validation Studies for Radiance/Daysim
Energy & Buildings Reinhart, Walkenhorst 2001
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illuminance threshold [lux]
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Energy & Buildings Reinhart, Andersen 2006
The Radiance/Daysim daylight simulation program can efficiently andreliably model annual illuminance time series with a mean relative errorof 20%.
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SimulationChecklist
Book Chapter: Reinhart C F, “Simulation-based Daylight Performance Predictions“ in Building Performance Simulation for Design and Operation, Editors J Hensen and R Lamberts, Taylor & Francis, 2011
http://daysim.ning.com/
Ongoing Daysim Activities
Fully documented API supported by the US DOE. We are giving up the Daysim JAVA GUI.
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Ongoing Daysim Activities
LBNL & Penn State: Greg Ward’s new three phase Methods is currently being fully integrated into DAYSIM. This will allows users to run annual daylight calculations BTDF functions from Windows 6 in Daysim.
Penn State: Addition of explicit electric lighting calculations in Daysim. This will allow users to specify and model actual luminaries and place photocell sensors in Daysim and link them to an annual electric lighting calculation.
Fraunhofer ISE: Linking of forward raytracing (photon mapping) into Daysim. Test version completed last week.
Once fully tested and matured, we will be adding these new functionalities to DIVA.
DIVA Approach to Daylighting
Figure from Daylighting Manual (Reinhart)
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Multidirectional Time-Lapse Simulation
Design: Jeff Niemasz
PaperJ A Jakubiec, C F Reinhart, “The Use of Glare Metrics in the Design of Daylit Spaces: Recommendations for Practice", LightingResearch and Technology 2012.
DGP yields most plausible results in these spaces.
Concept of the Adaptive Zone
Design: Jeff Niemasz
Annual DG Calculation: Fixed view looking forwardAnnual DG Calculation: Fixed view looking forward
Annual DG Calculation: +/‐ 45 degrees rotational freedomAnnual DG Calculation: +/‐ 45 degrees rotational freedom
The concept helps to quantify the benefits of flexible furniture settings etc.
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Occupant Behavior
architecture: Meier-Weinbrenner-Single, Nürtingenarchitecture: Meier-Weinbrenner-Single, Nürtingen
Monitoring User Behavior
Paper: Reinhart C F, Voss K, “Monitoring manual control of electric lighting andblinds.” Lighting Research & Technology, 35:3 pp. 243-260, 2003.
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HOBO data logger
IlluminanceTemperature
occupancy
Monitoring Setup in the Offices
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swit
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Hunt 1978
Lamparter 2000
Switch-On Probability (II)
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Switch lights on
Is work place already occupied?
YES
stochastic process:switch on probability
(Fig. 7-5)
NO
NO
YES
NOYES
Has the room been deserted for longer than sensor
delay time?
Are lights switched on?
Does occupant arrive?
Is there an occupancy sensor?
YES
YES
Switch lights off
NO YES
Does occupant leave?
Are lights switched on?NO
YES
stochastic process:Pigg’s switch off probability with or without occupancy
sensor (Fig. 7-5)
NONO
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Switch lights off
YES
YES
Does occupant leave?
NO
YES
stochastic process:intermediate switch on
probability (Fig. 7-7)
NO YES
Switch lights on
Does occupant arrive?YES
NO
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Lamparter
stochastic process:switch on probability
Lightswitch - Manual Lighting Control
Daylighting Dashboard
Paper Reinhart C F, J Wienold, “The Daylighting Dashboard - A Simulation-Based Design Analysis for Daylit Spaces”. Building andEnvironment, 2011 46:2 386-396
Daylit Area: 73% of the space 44% of the space
% Occupied hours
Potential glare: 50% of the year no glare View: 100% 50%
Question: Should I specify blinds or not?
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Daylighting vs. Thermal Model
workspace with high visual comfort
Once zone model with all surface facing outward. The link between the daylighting model and the thermal model is
the schedule file.
Daylighting Dashboard
Daylit Area: 73% of the space 44% of the space
% Occupied hours
Potential glare: 50% of the year no glare View: 100% 50%
Question: Should I specify blinds or not?
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Thank YouContactChristoph ReinhartAssociate Professor Massachusetts Institute of TechnologyEmail: [email protected]
MIT Sustainable Design LabKarthik Dondeti (MIT)Timur Dogan (MIT)Diego Ibarra (GSD)Alstan Jakubiec (MIT)Holly W Samuelson (GSD)John Sullivan (MIT)Tarek Rakha (MIT)
Solemma LLCAlstan JakubiecKera LagiosJeff NiemaszJonnie Sargent
www.daylight1-2-3.com
www.daysim.com