The document discusses lighting simulation tools used in an architectural lighting course. It describes SketchUp, Ecotect, and Radiance software that students will learn. Ecotect is demonstrated for daylight factor analysis and shading studies. Limitations are noted regarding sky models and accounting for multiple reflections in Ecotect simulations.

1. ARCH 447 Electrical Services - LightingARCH 447 Electrical Services - Lighting
Christoph Reinhart, Ph.D.Christoph Reinhart, Ph.D.
Oct 20: Lighting Simulation I - EcotectOct 20: Lighting Simulation I - Ecotect
Shading analysisEcotect Daylight Factor analysis

2. 1 Sep 1 Vision and Color
2 Sep 8 History of Lighting
3 Sep 15 Electricity
4 Sep 22 Lamps
5 Sep 29 Field Trip – custom fixture manufacturing workshop tour
6 Oct 6 Building Simulation & Daylighting Principles
7 Oct 13 Fixtures & Introduction of Studio project
8 Oct 20 Lighting Simulation I – Ecotect
9 Oct 27 Lighting Simulation II – Radiance
10 Nov 3 Lighting Simulation III – Radiance
11 Nov 10 Midterm project critique and introduction of final project parameters
12 Nov 17 Field Trip – tour of Montreal architectural lighting installations
13 Nov 24 Daylighting Techniques
14 Dec 9 Final Project Critique
Course Outline

3. Does the course web site work for everybody?
(online courses >> Electrical Services – Lighting ARCH 447)
Any questions on term project?
Take attendance.
Kristina Bondy & Daniel Juck: You should have access to ARCH software.
Request SketchUp/Form Z. Demo will follow in this lecture for SketchUp. FormZ
demo in drop-in lab.
Square One shop closed until next Monday.
Misc

4. Sketch Up, FromZ,...Sketch Up, FromZ,...
EcotectEcotect
3ds file3ds file
Radtool (Radiance)Radtool (Radiance)
rad filerad file
Simulation Tools used in this Course

5. Sketch Up
Installed on all ARCH computers.
Sketch Up
Installed on all ARCH computers.
Ecotect
Installed on all ARCH computers.
Site license, maximum number of
five sessions at the same time.
Ecotect
Installed on all ARCH computers.
Site license, maximum number of
five sessions at the same time.
Availability of Tools
Desktop Radiance
Installed on all ARCH
computers.
Desktop Radiance
Installed on all ARCH
computers.

6. Sketch Up
Download from www.sketchup.com
License issue unfortunately still
unresolved.
Sketch Up
Download from www.sketchup.com
License issue unfortunately still
unresolved.
Ecotect
Download from Square One
website. $US90 oer student
licence (Windows only).
Ecotect
Download from Square One
website. $US90 oer student
licence (Windows only).
Setting up your own computer (optional)
Desktop Radiance
Download from LBNL web
site (Windows or Mac).
Desktop Radiance
Download from LBNL web
site (Windows or Mac).
More details under:
online courses >> Electrical Services – Lighting ARCH 447 >> 1.2 software

7. (1) Installation Instructions on Course web site
(2) Download from LBNL web site
(3) Install preferably under “C:Radiance”
(4) Set link in Ecotect
Install Desktop Radiance on your PC

8. • introduce some daylight performance metrics
• daylight factor calculations in Ecotect
• simulation models
• avoidance of direct sunlight
Objectives for this lecture

9. Daylight Performance Metrics

10. Review - Photometric Quantities
Characterize how a space is perceived.
Luminous
Flux
Luminance
Luminous
Intensity
Illuminance
Computer simulation: luminances and illuminances

11. Luminous Distribution, cd/m2
Luminance L (absolute brightness)
Photo

12. sunny summer day 70000 - 100000 lux
cloudy summer day 20000 lux
cloudy winter day 3000 lux
requirement for reading 100 lux
requirement for office work 300 - 800 lux
Review - Typical Illuminance Values

13. category material
classification
example of
materials
lighting
illuminance
limiting annual
exposure
I insensitive metal, stone, glass,
ceramic
no limit no limit
II low sensitivity canvases, frescos,
wood, leather
200 lux 600 000 lux h /yr
III medium
sensitivity
watercolor, pastel,
various paper
50 lux 150 000 lux h/yr
IV high
sensitivity
silk, newspaper,
sensitive pigments
50 lux 15 000 lux h/yr
Museum Lighting
CIE TC3-22 ‘Museum lighting and protection against radiation
damage’

14. Review - Daylighting Definitions
Architectural definition: the interplay of natural light and building form to
provide a visually stimulating, healthful, and productive interior
environment
Lighting Energy Savings definition: the replacement of indoor electric
illumination needs by daylight, resulting in reduced annual energy
consumption for lighting
Building Energy Consumption definition: the use of fenestration systems
and responsive electric lighting controls to reduce overall building energy
requirements (heating, cooling, lighting)
Load Management definition: dynamic control of fenestration and lighting
to manage and control building peak electric demand and load shape
Cost definition: the use of daylighting strategies to minimize operating
costs and maximize output, sales, or productivity
**
*

15. Green Building Rating Systems I
LEED and Green Globe provide daylight
credits for:
! daylight factor
! view to the outside
! specification of shading devices
(Green Globe only)
Compliance is verified via spreadsheet method.
Do daylight factor & view LEED to good daylighting?

16. Daylight Factor Definition
E point
E outside horizontal
DF = (E point/E outside horizontal) * 100%
The DF is only defined under overcast skies!

17. Credit 8.1 Daylight 75% of Spaces 1 Credit
• Archive a minimum Daylight factor of 2%
(excluding all direct sunlight penetration) in 75%
of all space occupied for critical visual tasks.
Spaces excluded from this requirement include
copy rooms, storage areas, mechanical plant
rooms, laundry and other low occupancy support
areas. Other explanations for spaces where tasks
would be hindered by the use of daylight will be
considered on their merits.
Green Building Rating Systems II

18. Credit 8.2 Views for 90% of Spaces 1 Credit
• Achieve direct line of sight to vision glazing for building occupants in 90%
of all regularly occupied spaces. Examples for exceptions copy rooms,
storage areas, mechanical, laundry and other low occupancy support
areas. Other exemptions will be considered on their merits.
Green Building Rating Systems III

19. Historical Background: “Right of Light”
Waldram 1945Waldram 1945

20. Daylight Factor Use in Design
Pro:
! intuitive quantity
! overcast sky as a worst case scenario
! venetian blinds (even if closed) still admit sufficient DL
7%
3,5%
0%

21. Daylight Simulations in Ecotect

22. • Performance Metrics (daylight factor, avoidance of direct sunlight)
• Building Model
• Area of Interest (analysis grid)
• Sky Model
• Simulation Model
• Material Properties
Elements needed for a DL Simulation

23. Ecotect Demo - Prepare a simple
model, add a grid, start a simulation

24. CIE clear sky CIE overcast sky
Overcast sky: zenith to horizon 3-1
Sky Models: CIE Sky Model

25. Square One web site
Design Sky values are derived from a statistical analysis of outdoor
illuminance levels. They represent a horizontal illuminance level that is
exceeded 85% of the time between the hours of 9am and 5pm throughout
the working year. Thus they also represent a worst-case scenario that you
can design to and be sure your building will meet the desired light levels at
least 85% of the time.
Limitation in Ecotect. Climate files are not used by lighting simulation.
Design Sky Values

26. Average Daylight Factor (spread sheet method, similar to IESNA method)
Original Split Flux Method (Daylight Factor Protractors)
Points of Equal Sky Illuminance
Split Flux Method in Ecotect
Daylight Factor Calculation Methods

27. W = The area of each window (m²),
ττττ = Transmittance of each glazing material
θθθθ = Vertical angle of the sky as seen from the centre of each window
m = Maintenance factor based on angle of glazing and the cleanliness of its
environment (0.5 – 0.9),
A = Total internal surface area of the space, including walls, floors, ceilings and
windows (m²),
R 2= Area weighted average reflectance of all surfaces making up A, (use 0.1 as
reflectance for glass).
Average Daylight Factor Calculation

28. SC = direct component
ERC = externally reflected component
IRC = internally reflected component
DF= SC + ERC + IRC
UK Building Research Establishment (BRE)
Split Flux Method

29. Daylight Factor Protractors
SC
ERC
Square One web site

30. Square One web site

37. DF = SC + ERC + IRC
= 1.52% + 0.0456% + 1.7586%
= 3.324 %
In Montreal:
Design sky = 7215 Lux
Light Level = 7215 Lux x 3.324%
= 240 Lux

38. Square One web site
Points of Equal Sky Illuminance

39. Square One web site
A geometric version of the Split Flux Method (BRE)
Raytracing: each ray represents an approximately equal solid angle of sky
Split Flux Method in Ecotect

40. Split Flux Method in Ecotect
Square One web site
A Sky Component (SC) is modified by:
• relative sky illuminance of that particular sky patch
•relative angle of sky patch makes with a horizontal surface
•visible transmittance of each glazing material through which it travels

41. Split Flux Method in Ecotect
Square One web site
An Externally Reflected Component (ERC) is modified by:
• luminance of the sky it would have hit
• reflectance of the material assigned to the external object
• relative surface angle and glazing transmittances

42. Split Flux Method in Ecotect
Square One web site
An Internally Reflected Component (IRC) is modified by:
• store internal surface reflectance of the object
• altitude angle of the ray is used to determine which parts of the IRC
formula the ray contributes to.

43. Split Flux Method in Ecotect
Summing up over ray contribution and comparing it against the total
unmodified illuminance gives the Daylight Factor.

44. BRE Daylight Factor method uses a relatively simple formula for the effect of
internal reflections. To be fully compliant with this method, Ecotect cannot
consider multiple reflections. Therefore, Ecotect underestimates indirect daylight
solutions that rely on the reflection of light off multiple surfaces to illuminate a
space. Limitations of the sky model (Ecotect does not use annual climate file data
for daylighting).
Limitations of the Ecotect Approach

45. Ecotect Demo – Open GL & parameter
study

46. Daylight Factor – design implications
window head height !!!!reference
glazing type !!!! narrow floor plan !!!!

47. Daylight Factor – design implications II
The daylight factor optimized building is fully glazed.

48. Daylight Factor – design implications III
Daylight factor does not take glare or solar gain control
into account. The consequence of too large glazings:
The blinds are closed most of the time.

49. Avoidance of Direct Sunlight
Avoidance during cooling period (often assumed to be Apr 1st
to Oct 1st) or according to climate file.
For Montreal: May 1st to Oct 1st.
Resulting building design form is improved from an energy
standpoint.
optimized for static shading device
louvers, lightshelves etc. !!!!

50. Assign Shaded As…
Save As Bitmap…
Open GL …
Ecotect Demo – Shading Analysis
& design of a simple lightshelf

51. Ecotect Demo - import a SketchUp file

52. Material Properties
visual transmittance: windows, skylights, lightshelves
reflectivity of internal surfaces
external elements site obstructions and applied shading devices

53. Material Properties – Opaque Surfaces
specular
reflectance
diffuse
reflectance
mixed
reflectance
For a perfectly diffuse
surface (Lambert surface)
holds:
E.g. paper, drywall
π
ρE
L =

54. Material Properties

55. Ecotect Demo – Electric Lighting

56. (1) Submit your project proposals.
(2) Carry out a daylight factor and avoidance of direct sunlight analysis in
an office building of your choice. Required minimum illuminance level:
300 lux. Avoid direct sunlight from Apr 1st to Oct 1st.
Assignments for next week

57. Questions…Questions…