1 Ball State Architecture | ENVIRONMENTAL SYSTEMS 1 | Grondzik 1 DAYLIGHTING CONCEPTS Mt. Angel Library by Alvar Aalto; featuring a major daylight “fixture” Ball State Architecture | ENVIRONMENTAL SYSTEMS 1 | Grondzik 2 Daylighting Daylighting has always been of major importance, but somehow during the 1960s, we forgot everything we knew about the art and science of daylighting. Cheap energy and air conditioning did us in. William Caudill in the Foreword to Daylight in Architecture a reference to the allure and power of active systems
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Ball State Architecture | ENVIRONMENTAL SYSTEMS 1 | Grondzik 1
DAYLIGHTINGCONCEPTS
Mt. Angel Library by Alvar Aalto; featuring a major daylight “fixture”
Ball State Architecture | ENVIRONMENTAL SYSTEMS 1 | Grondzik 2
Daylighting
Daylighting has always been of major importance, but somehow during the 1960s, we forgot everything we knew
about the art and science of daylighting. Cheap energy and air conditioning
did us in.
William Caudill in the Foreword to Daylight in Architecture
a reference to the allure and power of active systems
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^^ Kimbell Art Museum, Ft. Worth, TX
Mt. Angel Library, Mt. Angel, OR >>
daylighting offers great opportunities for creative design
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Daylight Components
The daylight reaching a given point within a building generally consists of a mix of the following components (which show up as variables in some design analysis methods):
a sky component (SC)
an externally reflected component (ERC) an internally reflected component (IRC)
these components are related to — but not the same as — the direct, diffuse, and reflected components that comprise light falling on an aperture
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Daylight Components
DF = SC + ERC + IRC
the “sky” component is not the same as “direct solar” radiation
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A Daylighting Design Process
• Establish lighting system Owner’s Project Requirements• Daylighting may be a reasonable means of achieving OPR• If so, select a likely daylighting implementation method
(an approach or approaches)• Validate that the approach actually works (that the result
can meet intent and criteria) using appropriate design tools• Refine the initial design solution as required using
appropriate analysis tools; validate the final design solution• Develop construction drawings and specifications• Apply the commissioning process to the daylighting system
design (especially controls)• Construct the daylighting system and commission it• Occupy building; validate system in place and in use; learn
and communicate the lessons learned
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Daylighting Design Concerns
• The source of light is variable– addressed through the design process
– addressed via coordination with electric lighting
– addressed during usage by space occupants and controls
• The source of light is outside the building– light must be brought into a building
– light must be skillfully distributed from an aperture located at the periphery of a space
These are primarily architectural design issues– architects must take the lead
– daylighting potential is established with the first design moves (plan, orientation, and massing)
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General Daylighting Approaches
• Sidelighting– Unilateral or bilateral– Windows– Clerestories (if low)
• Toplighting– Skylights– Clerestories (if high)
• Hybrids and combinations
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what about “bottomlighting”?
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Sidelighting (if unilateral)
illuminance drops off fairly quickly as distance from aperture increases
illuminance pattern (lux, FC or DF) on horizontal task plane
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Sidelighting (if bilateral)
illuminance drops off fairly quickly as distance from aperture increases;but two opposing apertures help to balance light distribution across space;magnitude of drop-off is a function of distance between apertures
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Toplighting (if single aperture)
illuminance drops off fairly quickly as distance from edge of aperture increases
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Hybrid Approaches
illuminance from skylight fills in “gap” caused by sidelight distribution pattern;
overlapping patterns will increase illuminance
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Elements of a Daylighting System
• Daylight source the sky (not direct sun)
• Apertures (openings—such as windows or skylights)
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Daylighting System Elements
• Source (the sky not direct solar)– Macro scale: this is a function of geographic locale
– Micro scale: influenced by specific site conditions
• Apertures (openings)– These are a function of design decisions (placement in
building, size, number, orientation)
• Aperture modifications (lightshelves, shading devices, glazings, …)– These are a function of design decisions (and, to some
extent, product availability)
the site provides a resource that the designer can use, abuse, or ignore
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Daylighting System Elements
• Space geometry– This is a function of design decisions optimize
space layout and use the space itself to help distribute light
• Reflectances – These are a function of design decisions use
reflective surface finishes to spread light
• Illuminated thing (task, surface, …)– This is a function of space type and usage
good daylighting design is good architectural design
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More About Daylighting Glazing
• Glazing location (orientation, tilt, surroundings) is important
• Glazing aperture area and DF are related in a generally linear manner
• Usually, daylighting glazing should have a high VT (visible transmittance) and a low SHGC (solar heat gain coefficient)—characteristics that will be incompatible in many typical products
• Generally daylighting should involve no direct solar radiation (provide shading devices to ensure this without blocking diffuse daylight)
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More About Lightshelves
These elements are used with daylighting windows to more evenly distributedaylight in a space; they do not substantially increase the amount of daylight that is captured
– They can be external, internal, or both
– When used, they split a window area into “view” and “non-view” sections
– They can assist with shading against direct solar radiation (thus reducing heat gain and glare)
– Performance is not well documented—lightshelf design is more an art than a science
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Lightshelves
Inland Revenue (UK), image from LBL
exterior lightshelves, Milwaukee, winter
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Philips Exeter Academy, Exeter, NH; Library, Louis Kahn (1967)
campus contextbuilding context
Daylighting Example
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building massing
façade texture and layers
Philips Exeter Academy
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reading carrels and lounge area
Philips Exeter Academy
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grand entry staircase and structure
Philips Exeter Academy
note difference in “warmth” of light
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various views of structure (contrast of wood and concrete)
Philips Exeter Academy
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views up into central volume, showing minimal toplighting and smoke vents
Philips Exeter Academy
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bookshelf engages structure
user of stair engages structure
Philips Exeter Academy
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