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ENVIRONMENTAL DESIGN CONSULTANTS + LIGHTING DESIGNERS | atelierten.com
Circadian Daylight in PracticeDetermining a Simulation Method for the Design Process
Jessica Zofchak
A legacy of positive change
We are an international team of environmental design
consultants and lighting designers focused on delivering
sustainability to the planned and built environment.
International Experience
London
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Edinburgh
New York
New Haven
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We advocate creative, practical and appealing environmental
design strategies that improve energy efficiency, water
conservation, material selection, and carbon emissions reductions.
Enlightened perspective on the built environment
• Environmental Design
• Façade Optimization & Daylight Design
• Water System Optimization
• Resilience + Adaptation Planning
• Comfort + IEQ Consulting
• Lighting Design
• Benchmarking (LEED, LBC, etc.)
Services• Energy Analysis
• Net-Zero Consulting
• Verification
• Masterplanning
• Carbon Management
• Healthy Buildings
• MEP Engineering (international)
Circadian Lighting
Light regulates circadian
rhythms and production of
serotonin and melatonin, which
modulate sleep, energy and moods.
Factors Affecting Circadian Rhythm
• INTENSITY: Bright light resets the clock
• TIMING: light directed to the eye is only effective
when applied at a specific time.
• DURATION: Bright light has to be applied during a
certain amount of time depending on the intensity.
• WAVELENGTH: It is the use of white and/or blue
light that has an effect in melatonin suppression.
• SPATIAL DISTRIBUTION: the angle with which light
is projected towards the eye is very important. The
more the retina is covered by the light, the better
Circadian Daylight
Measuring Circadian Stimulus
Equivalent Melanopic Lux (EML) is a metric for measuring the biological effects of light on
humans. Photosensitive retinal ganglion cells (ipRGCs) regulate the human circadian response
to light. These are non-image forming photoreceptors within the eye. EML as a metric is
weighted to the ipRGCs response to light and translates how much the spectrum of a light
source stimulates ipRGCs and affects the circadian system
Light Exposure
Ancenstral
Modern
midnight dawn noon dusk midnight
brig
htn
ess
WELL Building Circadian Lighting Standard
“Light models or light calculations
(which may incorporate daylight) show
that at least 250 equivalent melanopic
lux is present at 75% or more of
workstations, measured on the vertical
plane facing forward, 1.2 m [4 ft] above
finished floor (to simulate the view of
the occupant). This light level is present
for at least 4 hours per day for every
day of the year” (WELL, 2016).
Simulation
Grasshopper Scripts
Method 1 – Transformed Horizontal Illuminance
Method 2 – Multi-Directional Vertical Illuminance
Comparative Results
Application
Existing Building Retrofit – Circadian Lighting Options
Existing Building Retrofit – Circadian Lighting Distribution
Existing Building Retrofit – Payback Analysis
Electric circadian lighting needs DOUBLE the Lighting Power Density (LPD) of typical energy efficient lighting design, so it’s use should be deployed
selectively to save energy, carbon, and cost.
More electric circadian lighting, meaning more energy use/cost, is needed without
an effective automated shading system (exterior shade would be even more
effective).
Incentives
85% of total workplace
costs are spent on salaries and
benefits, compared to less than
10% on rent and less than
1% on energy
Unhealthy
workplaces cost
organizations
approximately
$1,200 /person /year
Investments in
healthy
environments
have a
2 year payback
Recruitment and retention of
employees is greater for
organizations that invest in indoor
environmental quality. Turnover cost
of a professional is
1 year’s pay + benefits
ENVIRONMENTAL DESIGN CONSULTANTS + LIGHTING DESIGNERS | atelierten.com
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New York NY 10003
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Jessica Zofchak
