Karla Assign 2

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DCS 598 – Daylighting | Karla Grijalva | April 19th, 2011

AGI32 Daylighting Simulation and Performance Analysis

Tempe Transpor tat ion Center



DCS 598 – Daylighting | Assignment 2: AGi32 | 2

Project

The Tempe Transportation Center is located at 200 E. Fifth Street at the base of A-Mountain. The 40,300square foot facility has an exterior shaded courtyard and a transit plaza serving the METRO light rail andlocal and regional bus patrons. The building’s nearest coordinates are W111.937 and N33.426. Thebuilding is placed on site approximately 22.92 clockwise from North.

.Project Description The Tempe Transportation Center is a 3-story building that is programmatically organized in two bars: Atranslucent one that houses most office space and a more enclosed one in where private offices,conference areas, services and restroom are located.

Owner: City of TempeGross square footage: 40,300 sq. ft.Cost: $18.1 millionCompletion date: December 2008Architect: Architekton and Otak




The building’s groundfloor includes retail,transit store, securityoffice, and bicycle cellar(with bike repair andaccessories). Thesecond floor includesthe city of TempeTransportation Officeand Don CassanoCommunity Room. Thethird floor houses theTransit OperationsCenter and leasingspace.

Dayl ight ing Study

For this study the Southeast portion of second floor has been selected for the daylight analysis. Importantto note that this building is glass dominated on the North, East and South elevations. The West sidefunctions as a solid linear block providing thermal mass to this side of the building.

The following page describes the environmental goals that the project had, as the team design objectiveand client’s initiative was to foreseen LEED Platinum Certification . The items related to daylight arehighlighted.

http://www.tempe.gov/tim/Bike/pdfs/bicyclecellar.pdf

http://www.tempe.gov/tim/Bike/pdfs/bicyclecellar.pdf




Project Goals – environmental responseStrategies used to reduce the energy footprint by 52%:

green vegetated desert roof underfloor air distribution system solar hot water system natural lighting

energy efficient emergency electrical generation double-pane/low-emissive glass

retractable exterior shade screens – currently not working and they are in process of beingreplaced with a new system.

operable windows for natural ventilation

On-going sustainable practices in the facility:

public transportation regional bike station with secure parking, showers, lockers, services green cleaning and maintenance program water collection and reuse flexible design = 100 year building life green Touchscreen interactive educational program green leases for tenant spaces

Strategies supporting a healthy and productive work environment:

low emitting paints, sealants, carpets and agrifiber adjustable underfloor air distribution system natural lighting and window views from all regularly occupied offices

Reduced impact on natural resources:

construction waste reduced by 94% rapidly renewable materials regional materials recycled content in carpet, tile, millwork, ceiling finishes no/low emitting paints, sealants, carpets and agrifiber

“Reuse & Recycle” signage program innovative stormwater retention and reuse drought resistant native landscaping low flow/dual flush plumbing fixtures and waterless urinals graywater collection and reuse

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1 http://www.tempe.gov/greenprograms/transitcenter.htm

http://www.tempe.gov/greenprograms/transitcenter.htm







AGI32 Compu ter Model for the Dayl ight in g An alysis

The area of study is approximately 80 ft by 38 ft. As indicated by the yellow area in the below image.

Important points to indicate on regards the spaces and the study are the following:

1. 75% of the square footage the second and third level is open space that has been subdivided withremovable partitions. Partitions and furniture have not been included in this study. However this isquite important for a future analysis due to material might absorb some of the daylight coming insidethe space.

2. The open space between levels is connected by a central stair case, there are no walls surrounding onthree sides. Since the study is in the second level some light transmittance might flow in betweenlevels.

3. The community room exterior envelope might bounce light into the interior spaces in the northern sideof the building. This element was not included in the study.




Considerat ions pr ior to import the model

The basic model was in Revit, the necessary portion to model the 2nd

floor was extracted and exported toCAD format, then imported to AGI32.

Setting the Basic Model in AGi32

To export: Set a Box View only the

potion of second floor

Eliminate objects fromview that are not

applicable or not need tobe included in the study

Export to CAD only the3D view assigned to thesecond floor insteadexporting the whole file

After importing: Delete surfaces that are

not needed for analysis.

Simplify glazing units(Revit creates a box per

glazing panel-six surfacesper unit)

Split and organize glazingobjects in 5 differentlayers, this is the numberof glazing type units in thesecond floor of the building

Clean file from surfacesthat are doble (Revitcreates quite detailsassemblies not necessaryfor the model)

When importing: Apply material type and

properties per layer

Change the mesh to 1.1 tomake calculations run

faster2

Daylight Exterior ON modeto exterior surface

Daylight Exterior OFF forinterior material

Double sided surfaces

Single sided surfaces

Flip surfaces that are in theopposite direction to theanalysis

Materials

The following considerations where done during the assignation of materials to the building’s interior surfaces.

Materials with Light Reflectance (LR)Ceiling-4’x4’ acoustical panels 75%Wall 83%Carpet 75%Exposed Structure 0%Door Frames 50%Doors 29%

Concrete Masonry Wall 50%Curtain Wall Frame 70%

Material with TransparencyExterior Screen (South) 50%Small West Glazing 50%

2 This needs to be change carefully, changing the mash and patches might change calculations results.

See Appendix 1, Section B.

REVIT AutoCAD AGI32




For materials with transparency perhaps the most challenging part was the curtain wall system on theNorth, South and East elevations on the 2

ndfloor. This curtain wall system has several types of glazing

units (5 in total). All are insulated glass units (double pane), low Emissivity (Low E).

For this, the general glazing layer coming from Revit, was manipulated in CAD to have one different layerper type of glazing unit. These layers had to be imported one at time to the AGI model. The glazing typenumber corresponds to the data coming from the construction drawings.

The following table shows the types (per Architectural specifications):GlazingType

Outer Pane Inter Pane VLT

SC AssemblyThickness

6 ¼” thick clear glass PPG Solar Ban 60Low E glass on clear

69% 0.44 1”

7 ¼” PPG Caribia glass PPG Solar Ban 60Low E glass ontranslucent

52% 0.35 1”

8 ¼” PPG Caribia glass PPG Solar Ban 60Low E glass on clear

64% 0.45 1”

9 ¼” PPG Caribia glass PPG Solar Ban 60

Low E glass onspandrel

- - 1”

KT Fully TemperedGlass

N/A 69% 0.35 1/4” min

AGI32 Image from Surface Edit / Project Manager Menu

Type 8 glass was in fact modeled with a 59% Transparency blue filter, which provided the bluish colorthat building elevation, reflects in reality.

Setting the glazing properties in AGi32Sunlight in AGi is transmitted directly into the interior space by the “Daylight Transition Glass” andopenings in the model. For this reason it was really important in this exercise to set as accurate aspossible the different types of glazing in Tempe Transportation Center to obtain a good calculation. Since




glass units act as luminaries in AGi calculations, the existing variations in color and visible transmittance(VT) of the glass play an important role when choosing the surface type and its properties.

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Distr ibut ion and Performance

The goal set for the assignment was to calculate the daylight illuminance on two horizontal planes: at floorlevel and at work plane; as well as one vertical plane along the wall on the west side of the open space,for the equinox and solstice days for 2011 at 9am, 12pm and 3pm.

Dayl ight Analys is – At floor level on a 4’x 4’ grid on the Southeast corner of the building

Use of sky dome – It has a virtual ground plane with 18% reflectance.

Adaptive Subdivision – Maximum Subdivision Level 2, Minimum element Area (sq Ft) 0.50 and Element Iluminance Threshold 15.

Generat ion of Calculat ions

Even though calculations might run faster on the Model Mode tab, I decided to run the calculation under

the Render Tab. In this way I could be able to see how the light will propagate the space and stop thecalculation if I saw something not expected before the calculation was completed.

The method of calculation used was the Full Radiosity Method, which allows seeing the evolution of theradiosity process during calculations. This was an exciting part of the assignment.

The radiosity process exchanges the light via individual surfaces within the mesh until all light emitted andbouncing around the environment is accounted for. This state is called Convergence.

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The following pages include the Calculation Points and the Raytrace and Pseudo Color images for eachof the runs performed.

Note that the calculation point are indicating for noon time the percentage of points above the rage of 25

to 500 fc, this is LEED criteria for achieving the daylighting points for its rating system.

5

3 Refer to Appendix 1, part A.

4AGi32 version 2.1 Tutorials, Instant Gratification, page 9

5 Refer to Appendix 1, part C.




Equ ino x | March 20, 2011 Calculation Points

9:00amlluminance (Fc) Average= 893.63Maximum= 3104.379Minimum= 74.5501 Avg/Min= 11.92Max/Min= 41.39

12:00pmlluminance (Fc) Average= 346.97Maximum= 5104.73Minimum= 57.16 Avg/Min= 6.09Max/Min= 89.56 Max/Avg=12.79No.Points=194%Pts.Range(25-500)=93.81%

3:00pmlluminance (Fc) Average=268.76Maximum=4958Minimum=56.7 Avg/Min=4.74Max/Min=87.44




Sols t ice | Jun e 21, 2011 Calculation Points

9:00amlluminance (Fc)

Average= 417.09Maximum= 4456.46

Minimum= 28.44

Avg/Min= 14.69Max/Min= 156.92

12:00pmlluminance (Fc) Average= 120.62

Maximum= 339.49Minimum= 25.80 Avg/Min= 4.68

Max/Min= 13.16 Max/Avg=2.81No.Points=194

%Pts.Range(25-500)=100%

3:00pmlluminance (Fc)

Average= 79.73Maximum= 188.55

Minimum= 23.28





Equin ox | Septemb er 23, 2011 Calculation Points

9:00amlluminance (Fc)

Average= 901.8Maximum=

3442

Minimum= 32


12:00pmlluminance (Fc) Average= 143.53

Maximum= 399.48

Minimum= 30.86 Avg/Min= 4.64

Max/Min= 12.93Max/Avg=2.78No.Points=194%Pts.Range(25-500)=100%


Average= 122.45

Maximum= 2499.42Minimum= 17.71





Sols t ice | December 22, 2011 Calculation Points

9:00amIlluminance (Fc)Average=566.51Maximum=1300.10Minimum=33.68Avg/Min=16.81Max/Min=38.58

12:00pmIlluminance (Fc)Average=319.25Maximum=3170.45Minimum=27.74Avg/Min=11.53Max/Min=114.45Max/Avg=9.93

No.Points=194%Pts.Range(25-500)=88.14%

3:00pmIlluminance (Fc)Average=174.8Maximum=1909.13Minimum=14.71Avg/Min=11.89Max/Min=129.87




Raytrace Renderings

9:00am 12:00pm 3:00pm

Equinox | March 20, 2011

Solstice | June 21, 2011

Equinox | September 23, 2011

Solstice | December 22, 2011




Pseudo Color Renderings

9:00am 12:00pm 3:00pm

Equinox | March 20, 2011

Solstice | June 21, 2011

Equinox | September 23, 2011

Solstice | December 22, 2011




Il lum inance | Calculat ion Points _Numerical Summ ary

This table is the summary of the calculation points’ information provided in the previous pages. Thosestudies corresponded to the Solstice and Equinox days and the surface analyzed was the floor plane.

The maximum Illumination point in footcandels is register in Mach Equinox at noon and the minimumillumination point in December’s Solstice at 3pm. However, during September’s Equinox at 9am thehighest average of illuminance is registered among all studies. The lowest average corresponds to Juneat 3pm. Refer to table on following page.

The interior area has quite concentration of glare spots during the morning hours. Nonetheless, at noonthe illumination levels become more even (120-140 fc) during June and September. March andDecember have elevated illumination levels at this time varying from almost 400fc to 320fc.

The following graph reflects the comparison of the average iIlluminance in foot-candles (fc) at floor planeduring Equinox and Solstice days in 2011.

Ilumination(fc)

Date Time Avg Max Min Avg/Min Max/Min

20-Mar-11 9:00:00 AM 199.91 512.30 36.11 5.54 14.19

12:00:00 PM 397.10 5080.30 31.99 12.41 158.76

3:00:00 PM 165.96 4100.95 18.25 9.07 224.10

21-Jun-11 9:00:00 AM 417.09 4456.46 28.44 14.69 156.92

12:00:00 PM 120.62 339.49 25.80 4.68 13.16

3:00:00 PM 79.73 188.55 23.28 3.42 8.09

23-Sep-11 9:00:00 AM 901.80 3442.16 31.68 28.45 108.59

12:00:00 PM 143.53 399.47 30.86 4.64 12.93

3:00:00 PM 122.45 2499.42 17.71 6.92 141.21

22-Dec-11 9:00:00 AM 566.51 1300.10 33.68 16.81 38.58

12:00:00 PM 319.25 3170.45 27.74 11.53 114.45

3:00:00 PM 174.80 1909.13 14.71 11.89 129.87




Solst ice | Jun e 21, 2011 | Noon @ Work plane Calculation Points

Raytrace


Average= 901.8Maximum= 3442

Minimum= 32


Pseudo Color

0.00

100.00

200.00

300.00

400.00

500.00

600.00

700.00800.00

900.00

1000.00

9 : 0 0 A

M

1 2 : 0 0 P

M

3 : 0 0 P

M

9 : 0 0 A

M

1 2 : 0 0 P

M

3 : 0 0 P

M

9 : 0 0 A

M

1 2 : 0 0 P

M

3 : 0 0 P

M

9 : 0 0 A

M

1 2 : 0 0 P

M

3 : 0 0 P

M

20-Mar-11 21-Jun-11 23-Sep-11 22-Dec-11

F o o t c a n d e l s

Tempe Transportation Center Illuminace - Average @ Floot Level

Average




For noon summer solstice, the difference between floor plane and work plane studies turned to be anapproximately 11% decrease from the average illumination at floor.

This indicates one of the factors that materials play for daylight reduction levels in interior spaces. This isthat certain illumination is absorbed and the rest is reflected to the space.

Figure - Floor material reflectance

106.78

324.62

24.06

120.62

339.49

25.80

0.00

50.00

100.00

150.00

200.00

250.00

300.00

350.00

400.00

Avg Max Min

F o o t c a n

d e l s

Tempe Transportation Center Comparison among Floor and Work Plane - Solstice | June 21, 2011 - noo n

Work Plane

Floor




Sols t ice | Jun e 21, 2011 | Noon – Overcast & Screen

The next step on the analysis looked into the overcast sky condition for June 21, at noon time.Additionally, I looked into the external shade on the east elevation to see the illumination levels at thesetwo conditions and compare them also to the Clear Sky calculations previously simulated for this day.

Overcast Condition Exterior Screen Option Illuminance (Fc) Average=59.48Maximum=286Minimum=5.6 Avg/Min=10.62Max/Min=50.98Max/Avg=4.80No.Points=194%Pts.Range(25-500)=75.77%

Illuminance (Fc) Average=147.44Maximum=402Minimum=45.9 Avg/Min=3.21Max/Min=8.76Max/Avg=2.73No.Points=194%Pts.Range(25-500)=100%

Veil Screen




The table below shows that the average illumination levels are approximately 49% below with a Clear Skycondition. While the Exterior Screen increases the average illuminance in the interior of the office space.Upon the color of the screen this reflectance might be attenuated or eliminated to avoid more glare to theinterior of the space.

Ilumination

(fc)Date Description Avg Max Min Avg/Min Max/Min

June 21, 2011@noon - WorkPlane

Clear Sky 106.78 324.62 24.06 4.43 13.47

Overcast 59.48 285.55 5.59 10.62 50.98

Screen (40% VT) 147.44 402.00 45.90 3.21 8.76

324.62

285.55

402.00

106.78

59.48

147.44

24.065.59

45.90

0.00

50.00

100.00

150.00

200.00

250.00

300.00

350.00

400.00

450.00

Clear Sky Overcast Screen (40% VT)

F o o t c a n d e l s

Tempe Transportation Center Comparison among Sky Types and Screen - Sols tice | Ju ne 21, 2011

Max

Avg

Min




Sols t ice | Jun e 21, 2011 | Noon – Ilum inance at West Inter ior Wal l

For the vertical illuminance calculation point analysis, it was selected the wall on the west side of theopen office space. The values vary from 113 fc to 29 fc. Having the highest points located at the bottomedge of the wall.

Sols t ice | Jun e 21, 2011 | Noon – Exitance

The exitance calculations of the same wall resulted in a variation of approximately 20 foot-candles, whichresults from the color absorption of the wall.




Second Floo r Images - March 28 2011 @ 9am

When visiting the Tempe Transportation offices, I noticed the lack of use the artificial lighting except forthe reception area; most other fixtures were in the off mode.

Reception Area Open office space looking South




Open office space looking Northwest – No light are in on mode




View along west wall Staff Room located at the Southwest corner




Light Measurements - March 28 2011 @ 9am

During the visit to the building a light meter was used to measure foot-candle ’s levels along a work andfloor plane.

Point locationDistance from Window (ft) (fc)

Floor Plane 7 ft -14 8121 6628 40

Work Plane (3ft)

7 ft 21814 13421 9828 64




Findings

The goals set during the design development of the project were to provide the following horizontalillumination criteria (in footcandels):

Corridors 10

Offices (daylit) 20 ambient / up to 40 for taskConference Rooms 25Break Room 25Restrooms 15Storage 5

By looking the analysis results:

The design maximized daylighting, but it goes beyond the illumination criteria set bythe energy consultants. The daylight results in high levels of glare during morninghours on the east side of the building. Also this could be contributing to additional heatloads in the building.

Simulation and on-site measurements indicated foot-candles similar measurements,but they are above the proposed criteria.

The challenge is to provide sun control for the hours that sun light penetrates directlyinto the spaces.

Options:

Interior Shading This helps to control glare in the interior, but the contribution to reduce heating loads is minimal.Currently, roll down shades have been installed in the second floor only.

Exterior Shading Tempe Transportation Center has a mechanical Solar Veil Shading for sun control, as mentionedpreviously. However, it is not working properly. A new system might be implemented in thecoming months.

The type of exterior sun control is an important point since to study in most buildings located inPhoenix area. Those that have implemented a mechanical sun control system have shown withtime that the system requires high level of maintenance, which makes it complicated for theowner and maintenance operators of the building to keep them functioning properly.

A more passive solution for exterior shading controls that maximize views and minimize heatgains could be applied.




Sun Light Contro ls – From the Project’s Archive

Curious note:During the Design Development phase of the project, the energy consultants recommended the verticalfocused shading control device. However a Solar Veil was selected.This is the consultants’ recommendation of systems ordered by higher performance:

1. Focused Shading2. Egg Crate Shading3. Solar Veil Shading

It is quite possible that the selection of the system could have been value engineered, resulting on theapplication of the system less recommended. This makes another important point on regards the designand selection the right daylight strategies elements for a project. If the proposed design is quite intrinsic tothe project’s exterior envelope, it could result difficult to eliminate them from the project’s scope of work.







Appendix 1

A. Things to keep in mind when analyzing Daylighting in AGi32

The key to accurate daylight analysis using AGi32 is the assignment of the correct Surface Typedesignation to glazing and exterior surfaces. Interior surfaces require no special treatment.

Daylighting calculations using AGi32 follow several important assumptions:

1. AGi32 considers the following daylight components: sunlight, skylight and light reflected from a“virtual” ground plane.

2. Daylight can only be seen by an interior surface (interior of a Room or Object) AFTER it haspassed through a “Daylight Transition <Surface>.”

This is typically Daylight Transition Glass but can be a simple Daylight Transition Opening.3. All exterior surfaces must be classified as “Daylight Exterior Surfaces” to accumulate daylightcomponents.

4. “Daylight Transition Surfaces” will consider light reflected ONLY from “Daylight Exterior

Surfaces.”

5. Daylight models MUST contain at least one “Daylight Transition Surface” or “Daylight Exterior Surface” in order to compute daylight component.

6. The virtual exterior ground surface is automatically assigned a reflectance of 18% (averagereflectance of an exterior scene, by Eastman Kodak, circa 1904).

With these ideas in mind, we can create any model, classify all exterior surfaces as “Exterior DaylightSurfaces” and classify all glazing as “Daylight Transition Glass.” All interior surfaces may remainSingle-Sided or Double-Sided, as created using the Room or Object tools, or imported (importedsurfaces become Objects).

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If calculations are performed under clear or partly cloudy skies, you will want to enable AGi32’sAdaptive Subdivision feature with parameters set to “High” (Calculate Menu). This will ensure the bestpossible definition of sun patches on interior surfaces. For perfect sun patches, run a post-radiosityprocess ray trace on the render views of choice.

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B. Mesh Level

It indicates the Mesh Level of the selected surfaces. Mesh Level may be modified as necessary:increased to improve the surface's response to its environment, or decreased to improve calculationtimes (opposite considerations).The Mesh Level value may be entered directly (e.g., 4.1), or specified in the Mesh Level dialog. Touse the Mesh Level dialog, click in the Mesh Level text box and then click on the ellipsis (dots) icon(or Press F4).The Mesh Level syntax is as follows: <Patch level>.<Element Level>, per the Radiosity process usedin AGi32. Increasing the Patch Level and/or Element Level will increase your calculation times.

Note: Increasing the Patch Level, automatically increases the number of elements in each surface(even without additionally increasing the Element Level).

6AGi32 version 2.1 Tutorial, Daylighting, page 57




Transition Surfaces: Daylight Transition Glass (transparent) and Daylight Transition Opening surfacetypes only use the Patch Level specification and are originally meshed based on the "Initial Meshing -Transition Surface Types" settings in the Advanced System Settings dialog. These surface types donot include Elements (all light hitting the surfaces from other Patches or direct electric sources isabsorbed). Diffuse Daylight Transition Glass (diffuse) surface types are composed of Patches andElements and are originally meshed based on the "Initial Meshing -General Surface Types" settingsin the Advanced System Settings dialog.

Note: Changing the Mesh Level manually in the Surface Edit dialog requires a thorough knowledge ofhow patches and elements are used in the radiosity calculations. Changing these valuesinappropriately can lead to unreasonably long calculations times (at best) or to inaccurate simulations(at worst).

If you are unfamiliar with AGi32's radiosity process and need to refine your mesh, consider usingAdaptive Subdivision instead.

Adaptive Subdivision changes the sampling level of all surfaces based on the electric lighting and/ordaylighting beam patterns to create more accurate representations of the beam's interactions with thesurfaces. Applying Adaptive Subdivision generally results in more accurate renderings and calculated

values, with the necessary requirement of longer calculation times. Without exception, AdaptiveSubdivision should be applied to all Full Radiosity Method calculated environments before the finalresults are outputted from AGi32... For Daylighting, the High setting of 5 is recommended and insurescrisp shadows in direct sunlight cases.

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C. LEED Requirements for DaylightingThe United States Green Building Council's Leadership in Energy and Design (LEED) requirementsfor daylight spaces includes a criterion that 75% of the work plane illuminance should fall between 25and 500 footcandles.

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Some of the calculations performed placed an illuminance grid that included a parameter to show thepercentage of points in this range. Most of which exceeded the 75% criterion.

8AGi32 version 2.1 Help Systems, Adaptive Subdivision, page 350


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Karla Assign 2