webinar: daylighting design · pdf file1 caroline m clevenger, pe, ra architectural energy...

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Caroline M Clevenger, PE, RAArchitectural Energy CorporationBoulder, Coloradowww.archenergy.com

Webinar: Daylighting Design

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Provides information and tools to architects, engineers, lighting designers, and building owners to create more energy efficient buildings in California. Administered by the following utility companies:

Energy Design ResourcesEnergy Design Resources

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© Architectural Energy Corporation

OutlineOutline

Daylighting:– Motivation

– Challenges

– Design Goals

– Design Strategies

– Designer’s Tool Kit

– Case Studies

– Resources

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Daylighting MotivationDaylighting Motivation

Hagia Sofia, IstanbulPantheon, Rome

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MotivationMotivation

Kimball Museum, Fort Worth, Texas

"...Light is really the source of all being.... [a]ll material in nature, the mountains and the streams and the air and we, are made of Light which has been spent. . .” - Louis KahnGuggenheim, New York

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• Potential of improved educational performance – A study of 21,000 students in three school

districts involving 2,000 classrooms– Daylighting through skylights and large

windows indicated a beneficial effect on educational performance, with a 99% statistical certainty

Daylighting in Schools (1999, 2001, 2003) -- Heschong Mahone Group

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• Educational study indicated that students in the most daylit classrooms progressed :

– 20% faster on math tests than those students with the least daylight

– 26% faster on reading tests than those students with the least daylight

Daylighting in Schools (1999, 2001, 2003) -- Heschong Mahone Group


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• Potential of Improved retail performance

– A study of revenue from 108 stores of a chain retailer, where two-thirds had skylights and one-third did not

– Skylights indicated a positive and significant correlation to higher sales, with a 99% statistical certainty

Skylights and Retail Stores (1999, 2003) -- Heschong Mahone Group


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• Retail study indicated:

– A skylit store had, on average, sales revenue 40% higher than a store without skylights

– If a non-skylit store averaged $2/sf in revenue, a skylit store would average between $2.61 to $2.98/sf in revenue

Skylights and Retail Stores (1999, 2003) -- Heschong Mahone Group


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• “Artificial” windows installed in patient rooms:

– Patients hospitalized for shorter periods– Complained less– Required less pain medication

Stanford University Hospital Study


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• Achieve greater occupant well-being, happiness, and satisfaction

• Improve employee retention and reduce employee “churn”

• Reduce absenteeism• Reduce environmental impact of the

building

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• Enhances design

• Sets body’s circadian rhythm / biological clock

• Increases connection to outdoors

• Full spectrum lighting

• Potential energy savings

Benefits of Daylight

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Full Spectrum Lighting

www.lightingdesignlab.com/articles/cri/cribig.htm

Color Rendering Index

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Heat gain (watts) per 1,000 lumens

Incandescent

T12 fluorescent withmagnetic ballast

T8 fluorescent withelectronic ballast

Clear glass

Reflectivebronze glass

0 20 40 60

Spectrally selective,tinted low-e glass

Electriclighting

Daylighting

Heat Gain from Different Light SourcesHeat Gain from Different Light SourcesEfficient Heat Gain

Based on E Source

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Winter Day Electrical Load ShapeWinter Day Electrical Load Shape

Exterior lightingInterior lightingOther

CoolingVentilationWater heating, cooking,and refrigeration

Heating

Winter Peakaverage of all U.S. commercial buildings

1,500

500

04 8 12 16 20 24

Hours

1,000

Source: EPRI CommendDatabase

Potential Energy Savings

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Summer Peakaverage of all U.S. commercial buildings

2,000

1,500

1,000

500

04 8 12 16 20 24

Hours

Exterior lightingInterior lightingOther

CoolingVentilation

Heating

Water heating, cooking,and refrigeration

Source: EPRI CommendDatabaseSummer Day Electrical Load ShapeSummer Day Electrical Load Shape

Potential Energy Savings

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Savings From Increased Productivity

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Why Use Daylight? A Review

• Architectural Factors– Space definition– Establishes character of space– Establishes exterior expression

• Human Factors– Psychological connection to outdoors– Improve occupant health and well-being– Improve worker productivity – Improve occupant satisfaction with indoor

environment• Energy Efficiency

– Lighting a major building load & cost– Reduces coincident electricity demand

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Daylighting ChallengesDaylighting Challenges

• Variable Solar Resource• Heat Gain• Problematic Glare• Contrast Ratios• Unbalanced Luminous

Environment • UV damage

Opryland Hotel, Nashville, Tennessee

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Variable Resource Variable Resource

Variable Light Source

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Daylighting GeometryDaylighting Geometry

Winter

Altitude A = 90 - Latitude L +/- Declination D

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Daylighting GeometryDaylighting Geometry

Parallel Solar Rays

Solar Intensity

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UV3%

Visible(45%) Near-infrared (52%)

300 500 700 900 1,100 1,300 1,500 1,700 1,900Wavelength (nm)

Spectral distribution of solar radiation

Eye sensitivity curve

Relativeintensity

Solar SpectrumSolar Spectrum

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Diffuse and Direct ComponentsDiffuse and Direct Components

Earth’s Atmosphere and Daylighting

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Variable Solar ResourceVariable Solar Resource

Relationship of Clouds and Solar Resource

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Problematic GlareProblematic Glare

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Luminance RatiosLuminance Ratios

• Background of visual task: Environment 3:1

• Background of visual task: Peripheral field 10:1

• Light Source: Adjourning field of view 20:1

• Interior in general 40:1

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Glare Index Glare Index

Electric Daylight

• Public Spaces (dark surroundings) 22 24

• Working spaces 19 22(occasional visual task)

• Visual Task (high contrast) 16 20

• Visual Task (low contrast) 10 16

Weighted ratio of the light source and background illuminance

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Daylighting DefinedDaylighting Defined

The purposeful use of daylight to meet the illumination requirements of an architectural space.

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Daylighting Design Goals

• Provide 100% of ambient lighting

• Meet illuminance requirements

• Minimize glare and high contrast ratios

• Provide balanced luminous environment

• Integrate with electric lighting system

• Integrate with HVAC system

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Design Goals

• Provide 100% of Ambient Lighting

– Employ ambient - task - accent lighting scheme

– Reduce/eliminate need for electric lighting– Compatible with VDT work environments– Create peaceful, calming luminous

environment

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Design Goals

• Meet Illuminance Requirements

– Address the visual requirements of the space

– Address requirements of the visual task (IES-RP-1-1993 Office Lighting, etc.)• Provide adequate levels of light• Provide proper placement/directionality of light• Provide adequate visual acuity

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Design Goals• Minimize Glare and High Contrast Ratios

– Use reflected light when possible– Light from the sky-dome, not the sun – Use care in selecting window and interior

finishes and colors– Avoid direct sunlight penetration and

associated sun patches on workplane

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Design Goals• Provide Balanced Luminous Environment

– Provide even illuminance in daylit space– Provide balanced lighting

• Light from multiple directions, if possible• Avoid high contrast ratios

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Design Goals• Integrate with Electric Lighting System

– Blend with architecture and interior design scheme

– Match colors of light– Provide reliable automatic control

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Design GoalsDesign Goals

• Integrate with Mechanical System– Account for reduced cooling load in HVAC

equipment sizing– Combine with daylight - occupancy controls

-- to regulate supply air delivery to the daylit space

http://www.hpac.com/member/feature/2002/0212/0212daley6.gif

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Savings from Daylighting ControlsSavings from Daylighting Controls

Source: Scott Ellinwoodand Associates

Energy use(kWh) inthousands

0

20

40

60

80

100

Lights HVAC(Heat pumps)

Total

No controls Two-step on/off controls

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Source: SouthernCalifornia Edison

Top daylighting

Side daylighting

Daylighting StrategiesDaylighting Strategies

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• Side Daylighting

– Daylight access from perimeter

– Orientation dependent– Typical for multi-story

buildings, such as offices, schools, etc.

– Control of direct sunlight penetration onto work surfaces essential

– Control of glare and contrast ratios essential

– Creates perimeter zone (up to 70% of floor can be perimeter space.)

Strategies: Side-lightingStrategies: Side-lighting

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Lightshelves

Light Redirecting Systems


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• “Tune” glazing optical properties by function and by orientation

• Separate “view” glass from “daylight” glass

• Direct daylight to ceiling

• Control occupant view of daylight glazing

View Glass

Daylighting GlassInterior Light She lf

Daylighting Glass Shade Control

View Glass Shade Control


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• Top Daylighting

– Daylight access from roof– Typically limited to top floor or

single story buildings – Can provide uniform

illumination– System orientation

independent of building orientation

Strategies: Top-lightingStrategies: Top-lighting

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Clerestories

Tubular Skylights


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• “Tune” glazing optical properties by orientation

• Control (minimize) direct sunlight penetration to reduce solar heat gain and glare

• Diffuse daylight for uniform illuminance levels


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Strategies: Solar ControlStrategies: Solar Control

http://gaia.lbl.gov/hpbf/techno_a.htm

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Daylighting Designer’s ToolkitDaylighting Designer’s Toolkit

Use Analysis:– Physical Models

– Computer Simulations

To Inform:– Architectural Design

– Solar Control Systems

– Glazing Selection

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Designer’s ToolkitDesigner’s Toolkit

Spectrally Selective Glazing

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Designer’s ToolkitDesigner’s Toolkit

Physical Scale Models

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Physical Scale ModelsPhysical Scale Models

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Computer ModelingComputer Modeling

Radiosity Backward Ray Tracing

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• SkyCalchttp://www.energydesignresources.com/tools/

skycalc.html

• SPOT™http://www.archenergy.com/SPOT

• SuperLitehttp://eetd.lbl.gov/btp/superlite20.html

Software SurveySoftware Survey

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• Radiancehttp://radsite.lbl.gov/deskrad/

– Desktop Radiancehttp://radsite.lbl.gov/deskrad/

– Rayfronthttp://www.schorsch.com/rayfront/

• AGI3.2http://www.agi32.com/

• Lightscape http://www.lightscape.com/

Software Survey, cont.Software Survey, cont.

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• Trace-Prohttp://www.lambdares.com/

• Lumen Microhttp://www.lighting-technologies.com/

• Ecotecthttp://www.squ1.com/

Software Survey, cont.Software Survey, cont.

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Computer Simulation: RadianceComputer Simulation: Radiance

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Photographs Simulations


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Computer Simulation: SkyCalcComputer Simulation: SkyCalc

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Computer Simulation: SPOT TMComputer Simulation: SPOT TM

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Daylighting Case StudiesDaylighting Case Studies

Xilinx Corporation, Longmont ColoradoDTJ Design, Inc.

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Case Study: XilinxCase Study: Xilinx

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7474



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Case Study : CTLMCase Study : CTLM

Center for Technology and Learning Media, Golden ColoradoAnderson Mason Dale Architects

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www.energydesignresources.com• Design Briefs and Guidelines• Case Studies• Software tools (Skycalc, SPOT, eQuest)• Online Tools: EDR Charrette• eNewsletter• Training Seminars (webinars, on-site,

on-line)

Daylighting Tools and ResourcesDaylighting Tools and Resources

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• www.savingsbydesign.com• Set guidelines for exceeding T-24

standards• Design assistance• Incentives for owner ($150k max)• Incentives for design team ($50k max)• Two approaches:

– system or component– whole building

Savings By Design ProgramSavings By Design Program

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• www.pge.com/biz• New construction design assistance• Cash incentives• Customized energy efficiency/demand

response incentives• Energy efficiency equipment rebates• Self generation incentives and rates• Education and training

PG&E Tools and ResourcesPG&E Tools and Resources

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• www.pge.com/pec/• PEC architectural

programs provide information to assist designers

• Tools available such as the Heliodon for shading studies

• Education and training classes and printed material

Pacific Energy Center ResourcesPacific Energy Center Resources

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• LEED Green Building Rating System®– www.usgbc.org

• Whole Building Design Guide– www.wbdg.org

• Smart Communities Network– www.smartcommunities.ncat.org/buildings

/gbintro.shtml• Collaborative for High Performance Schools

– www.chps.net

Other Relevant ResourcesOther Relevant Resources

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• Building Green– www.buildinggreen.com

• Great Energy Efficient Buildings– www.greatbuildings.com/types/types

/geeb.html • National Renewable Defense Council

– www.nrdc.org/buildinggreen/• State of California

– www.green.ca.gov/default.htm

Other Relevant ResourcesOther Relevant Resources

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Caroline M Clevenger, PE, RAArchitectural Energy CorporationBoulder, Coloradowww.archenergy.com

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webinar: daylighting design · pdf file1 caroline m clevenger, pe, ra architectural energy...

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