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DIVA Day / Introduction to SImulating LEEDv4 Daylighting Credit Compliance 12 October 2014
Introduction to Simulating LEEDv4 Daylighting Credit Compliance and IES-LM-83
2 October 2014
J. Alstan [email protected]
CTO, Solemma LLC
DIVA Day / Introduction to SImulating LEEDv4 Daylighting Credit Compliance 22 October 2014
A Very Brief History of LEED Simulation-based Daylight Credit Compliance
LEED 2.1 (2002)
LEED 2.2 (2005)
LEED 2009 (2009)
LEED 2009 Addendum
LEEDv4 (2013)
Achieve a minimum Daylight Factor of 2% (excluding all direct sunlight penetration)
in 75% of all space occupied for critical visual tasks.
Achieve at least 25fc illuminance in 75% of all regularly occupied areas under clear sky
conditions at noon on the equinox.
Achieve at least 25fc but no more than 500fc illuminance in 75% of all regularly
occupied areas under clear sky conditions at 9AM and 3PM on the equinox.
Achieve at least 10fc but no more than 500fc illuminance in 75% of all regularly
occupied areas under clear sky conditions at 9AM and 3PM on the equinox.
Achieve a Spatial Daylight Autonomy (sDA300lx,50%) in 55% (2pts) or 75% (3pts) with
Annual Sunlight Exposure (ASE1000lx,250h) below 10% in all regularly occupied floor areas.
DIVA Day / Introduction to SImulating LEEDv4 Daylighting Credit Compliance 32 October 2014
IES-LM-83: What is it?
• In short, where the LEEDv4 daylighting compliance requirements come from.
• An approved method by the Illuminating Engineering Society (IES) Daylight Metrics Committee. This
resulted in two new metrics for daylit spaces.
∆ Spatial Daylight Autonomy (sDA300lx,50%)
∆ Annual Sunlight Exposure (ASE1000lx,250h)
• LM-83 also attempts to standardize many unknowns in typical simulation processes.
∆ Shading controls
∆ Occupancy
∆ Unknown material reflectances
∆ Workplane height and sensor spacing
∆ Modelling guidelines (furniture, window mullions, context)
∆ Simulation parameters (light reflections, simulation detail)
DIVA Day / Introduction to SImulating LEEDv4 Daylighting Credit Compliance 42 October 2014
Standardized Occupancy Schedules
8AM - 6PM daily, 365 days per year. 10 * 365 = 3650 occupied hours in a standard year.
DIVA Day / Introduction to SImulating LEEDv4 Daylighting Credit Compliance 52 October 2014
Shading Controls
When more than 2% of a space’s floor area is covered by 1000lx of illuminance from direct sunlight
(as in a 0 ‘ambient bounce’ lighting calculation), shading devices will be lowered to block the sunlight.
6.9% Direct Sunlight7am Sept 21, Boston, MA USA
24.6% Direct Sunlightnoon Sept 21, Boston, MA USA
2.7% Direct Sunlight5pm Sept 21, Boston, MA USA
Percentages of direct sunlight present in a space as calculated with DIVA.
DIVA Day / Introduction to SImulating LEEDv4 Daylighting Credit Compliance 62 October 2014
Modeling Guidelines
When unknown, use the following...
- 30% vertical exterior surfaces reflectance
- 20% trees reflectance
- 10% ground reflectance
- 20% floor reflectance
- 50% wall reflectance
- 70% ceiling reflectance
- 50% furniture reflectance
Material Properties
Model fixed furniture 36” above the floor and
greater within 6” of accuracy.
Furniture
DIVA Day / Introduction to SImulating LEEDv4 Daylighting Credit Compliance 72 October 2014
sDA300lx,50%
Three Annual Simulations Piece Together Results
Shades Open
• sDA300lx
Percentage of occupied hours
where 300 lx is met by daylight
alone.
• sDA300lx,50%
If the sDA300lx percentage
of hours > 50%, the area
represented by the sensor is
daylit. Typically the floor area
meeting this requirement.
• LEEDv4
If sDA300lx,50% comprises > 55%
of floor area, you get two LEED
points. >75% of floor area,
three LEED points.
Shades Closed (*N states)
Direct Sunlight Only (ab 0)Close shades when
sunlit area > 2%
Hour 1
.
.
.
Hour 09
Hour 10
Hour 11
Hour 12
Hour 13
Hour 14
Hour 15
Hour 16
Hour 17
.
.
.
Hour 8760
dir
ect
sun
nlig
ht
>2%
flo
or
area
DIVA Day / Introduction to SImulating LEEDv4 Daylighting Credit Compliance 82 October 2014
sDA300lx,50%: Three Annual Simulations, Pieced Together
Shades open. Red = 300 lx.
sDA300lx Results
Note: Shades close when the floor area exposed to direct sunlight >2% of the total.
Shades closed. Red = 300 lx.
Direct sunlight (ab 0). Red = 1000 lx.
DIVA Day / Introduction to SImulating LEEDv4 Daylighting Credit Compliance 92 October 2014
ASE1000lx,250h: Very Simple
• No window shades. One 0 ambient bounce simulation --
direct sunlight only.
• Result is the number of occupied hours greater than 1000lx.
• Try to have less than 250h (6.85% occ-h).
ASE1000lx Results
Direct sunlight (ab 0). Red = 1000 lx.
Direct sunlight (ab 0). Red = 1000 lx.
DIVA Day / Introduction to SImulating LEEDv4 Daylighting Credit Compliance 102 October 2014
Example Building: Net Zero Energy School in Boston Climate
Note: Furniture is actually not included in these simulations.
DIVA Day / Introduction to SImulating LEEDv4 Daylighting Credit Compliance 112 October 2014
Second Floor Analysis
DIVA Day / Introduction to SImulating LEEDv4 Daylighting Credit Compliance 122 October 2014
Daylit Areas (green)
DIVA Day / Introduction to SImulating LEEDv4 Daylighting Credit Compliance 132 October 2014
LEED NC2.1: Daylight Factor
2
0
1
1.5
0.5
Daylight Factor(%)
18.4% of floor area has a DF%>2.
Requirement: 75% of floor area.
DIVA Day / Introduction to SImulating LEEDv4 Daylighting Credit Compliance 142 October 2014
LEED 2009 Addendum: Equinox Illuminance at 9AM
500
> 500
illuminance (fc)
10
< 10
255
378
133
62.5% of floor area is between 10-500fc at 9AM
on a clear equinox day.
DIVA Day / Introduction to SImulating LEEDv4 Daylighting Credit Compliance 152 October 2014
LEED 2009 Addendum: Equinox Illuminance at 3PM
500
> 500
illuminance (fc)
10
< 10
255
378
133
51.2% of floor area is between 10-500fc at 3PM
on a clear equinox day.
DIVA Day / Introduction to SImulating LEEDv4 Daylighting Credit Compliance 162 October 2014
LEED 2009 Addendum: Both Illuminance Calculations
comply
9am does not comply
3pm does not comply
both do not comply
51.2% of floor area is between 10-500fc at 9AM
and 3PM on a clear equinox day.
Requirement: 75% of floor area.
DIVA Day / Introduction to SImulating LEEDv4 Daylighting Credit Compliance 172 October 2014
LEEDv4: Spatial Daylight Autonomy
100sDA (% occ.-h)
0
50
75
25
27.5% of the floor area has a sDA300lx value
greater than 50% of occupied hours.
Requirement: 55% of floor area (2pts).
75% of floor area (3pts).
DIVA Day / Introduction to SImulating LEEDv4 Daylighting Credit Compliance 182 October 2014
LEEDv4: Annual Sunlight Exposure
250
> 250
ASE >1000lx (h)
0
125
188
63
10.9% of the floor area has a ASE1000lx value
greater than 250 hours.
Requirement: Less than 10% of floor area.
DIVA Day / Introduction to SImulating LEEDv4 Daylighting Credit Compliance 192 October 2014
Panel Discussion
Ed Clark Eddy Santosa Kevin Van Den Wymelenberg
Associate Professor, U. Idaho
Director, Integrated Design Lab
Chair, IESNA Daylight Metrics
Committee
Building and Energy
Performance Group, Callison
Associate, ZGF Architects LLP