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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

0

10

20

30

40

50

60

0 200 400 600 800 1000

illuminance threshold [lux]

Day

ligh

t A

uto

no

my

[%]

measured

simulated

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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0.25

0.5

0.75

1

0 100 200 300 400 500 600minimum work plane illuminance [lux]

swit

ch-o

n p

rob

abil

ity

at a

rriv

al

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

NO

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

NO0

0.2

0.4

0.6

0.8

1

0 100 200 300 400 500 600minimum work plane illumiance [lux]

sw

itc

h-o

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rob

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Hunt

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: creinhart@mit.edu

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