CBT Architects present how they are integrating IES building performance analysis into their design process using the Fitchburg State Science Project as an example for this Case Study. This an interesting insight into how this architectural firm is going about incorporating early stage analysis into their processes, BIM and working in a more integrated manner with the engineer. The presentation is based on one given to a group from the Harvard Business School’s facilities and construction department.

1. FITCHBURG STATE
Liam O’Sullivan
UNIVERSITY
Chad Reilly Building Performance
Alfred Wojciechowski Modeling
Presenters
Energy Reduction
Strategies
October 27, 2011

2. agenda
part 1:
cbt – tools + process
a. software
b. products
part 2:
fitchburg state science project
a. overview of the building design
b. the players in building performance
part 3:
collaboration – team + process
a. mep engineer
b. commissioning agent
c. energy modeling consultant
part 4:
cbt – ies + process
total cost savings / lessons learned

3. fsu project overview
• 105,425 total square feet
– 55,625 addition
– 49,800 renovation
• LEED silver targeted (state mandated)
• new wing: biology (8 labs), chemistry
(3 labs), student lounges
• existing wing: physics (3 labs), geology
(2 labs), classrooms, faculty offices
• on main campus road and terminus of
main quad

4. fsu site location

5. fsu site context
biology labs + support
shared sciences
physics labs + classrooms

6. fsu elevations

7. cbt process evidence based design + building information modeling (bim)
3D visualization – design communication coordination
• sketchup, photoshop, revit, navisworks, physical models
data rich – capture and retrieve information
• revit
simulations – building components and elements
• ecotect, ies

8. 3D visualization sketchup + photoshop

9. data rich revit – schematic design building area + program analysis

10. 3D visualization sketchup + cad + photoshop

11. 3D visualization revit – bim model
• structure
• floor slab
• plumbing
• fire protection
• hvac
• electrical
• walls + ceiling
• furniture +
cabinetry

12. 3D visualization revit – bim model
• completed building
• combined revit model

13. 3D visualization revit – bim model

14. simulations ecotect

15. simulations ies (integrated environmental solutions)

16. collaboration
team + process

17. energy reduction collaboration
core design team members
cbt – architect
• overall coordination
• building performance modeling
mechanical, electrical + plumbing
engineer
• develop systems
• maintain code compliance
energy modeling consultant
• traditional energy modeling
• identify energy reduction
opportunities
commissioning agent
• advise end user on operations
• identify energy reduction
opportunities

18. mep design systems development (sd phase)

19. commissioning energy + water savings strategies report (dd phase)
key components
• building description + proposed mep
systems
• proposed energy + water savings
strategies
• labs21 benchmarking analysis
• ashrae integrating energy strategies
in accademic lab facilities
• case studies
• bridgewater state college
• umass amherst new science
building
• yale university new engineering
building
• national renewable energy lab

20. commissioning comparative analysis (dd phase)

21. energy modeling analysis + recommendations (dd phase)

22. collaboration outstanding issues matrix (dd phase)

23. building performance modeling integrated, evidence based design
9000
8000
7000
6000
5000
Load (Btu/h)
4000
3000
2000
1000
0
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 01
Date: Mon 01/Dec to Wed 31/Dec
Heating plant sensible load: 301 Lab Organic (all_fins_dec.aps) Heating plant sensible load: 314 Nursing / Indust (all_fins_dec.aps)

24. energy modeling verification report

25. cbt
ies + process

26. specifics of building performance modeling
revit generated model ies generated model
main topics:
• site conditions
• building envelope
• building facade
• daylight harvesting
• artificial lighting
• natural ventilation

27. site solar shading analysis of adjacent hill
23 M ay 18: 00
23 May – 6:00 PM
zone of influence

28. building envelope insulation – wall
• wall insulation (base case) • wall insulation (20% above code)
• 2 ½ʺrigid insulation • 4ʺrigid insulation
• U-value = 0.062 BTU/hr∙ft²∙ºF • U-value = 0.043 BTU/hr∙ft²∙ºF
• additional $0.85/sf over 14,920 sf
• hypothesis
• more insulation will result in lower energy use and operating costs

29. building envelope insulation – wall
MARGINALLY REDUCED HEATING LOAD NEGLIGIBLY IMPROVED COOLING LOAD
450000 350000
2 ½ʺ
400000 300000
insulation
350000
4ʺ insulation 250000
300000 200000
Load (Btu/h)
Load (Btu/h)
250000 150000
200000 100000
150000 50000
100000 0
Sun Mon Tue Wed Thu Fri Sat Sun Sun Mon Tue Wed Thu Fri Sat Sun
Date: Sun 21/Dec to Sat 27/Dec Date: Sun 20/Jul to Sat 26/Jul
Heating plant sensible load: 96 rooms (increase wall to 4 inch insulation.aps) Heating plant sensible load: 96 rooms (base_case.aps) Cooling plant sensible load: 96 rooms (increase wall to 4 inch insulation.aps) Cooling plant sensible load: 96 rooms (base_case.aps)
heating plant sensible loads during winter solstice cooling plant sensible loads during summer solstice
$290/ yr.
• results
• increasing insulation beyond 2 ½ʺresulted in very minimal savings and made no
difference in envelope performance
• net first cost savings to NOT use 4ʺthick insulation: $12,500

30. building envelope insulation – roof
• roof insulation (base case) • roof insulation (20% above code)
• 5ʺminimum rigid insulation • 6ʺminimum rigid insulation
• U-value = 0.048 BTU/hr∙ft²∙ºF • U-value = 0.040 BTU/hr∙ft²∙ºF
• additional $1.50/sf over 31,750 sf
• hypothesis
• more insulation will result in lower energy use and operating costs
MARGINALLY REDUCED HEATING LOAD NEGLIGIBLY IMPROVED COOLING LOAD
420000 350000
400000
300000
380000
360000
250000
340000
320000 200000
Load (Btu/h)
Load (Btu/h)
300000
5ʺ insulation
280000 150000
6ʺ insulation
260000
100000
240000
220000
50000
200000
180000 0
00:00 06:00 12:00 18:00 00:00 00:00 06:00 12:00 18:00 00:00
Date: Wed 24/Dec Date: Sun 20/Jul
Heating plant sensible load: 96 rooms (increase roof insulation.aps) Heating plant sensible load: 96 rooms (base_case.aps) Cooling plant sensible load: 96 rooms (increase roof insulation.aps) Cooling plant sensible load: 96 rooms (base_case.aps)
heating plant sensible loads (dec. 24th) cooling plant sensible loads (july 20th)

31. building envelope insulation – roof
$4,260/ yr. 5ʺ insulation
+$186/ yr. 6" insulation
modeling results of upgrading roof insulation to code (5ʺminimum thickness)
and to 20% above code (6ʺminimum thickness) – condike roof
$205/ yr. 6" insulation
modeling results of upgrading roof insulation to 20% above code
(6ʺminimum thickness) – new addition roof
• results
• increasing insulation to code (5ʺ minimum thickness resulted in savings of
)
$4,260 annually
• increasing insulation to 6ʺresulted in very minimal savings and made no
difference in envelope performance
• minor heating savings achieved during the winter are offset during remaining
seasons when it is beneficial to have less insulation trapping heat within the
building
• net first cost savings to NOT use insulation thicker than 5ʺ: $47,500

32. building envelope heating + cooling loads
400000
HEATING LOAD DOMINANCE
350000
300000
250000
Load (Btu/h)
200000
150000
100000
50000
0
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan
Date: Wed 01/Jan to Wed 31/Dec
Cooling plant sensible load: 96 rooms (increase wall to 4 inch insulation.aps) Heating plant sensible load: 96 rooms (increase wall to 4 inch insulation.aps)
annual heating and cooling plant sensible loads

33. building envelope glass
• high perfomance glass • super high perfomance glass
• ¼ʺviracon glazing • ¼ʺsolarban glazing
• ½ʺ air space cavity • ½ʺ airspace cavity
• ¼ʺclear float glazing • ¼ʺ clearfloat glazing
• U-value = 0.28 BTU/hr∙ft²∙ºF • U-value = 0.28 BTU/hr∙ft²∙ºF
• solar heat gain coefficient = 0.35 • solar heat gain coefficient = 0.27
• additional $25/sf over 8,008 sf
• hypothesis
• super high performance glass will lower operating costs and be worth the initial
cost increase

34. building envelope glass
high performance
glass
Delta = 4,000 MBTU / year (0.59% of max)
super high
performance glass
• cooling loads: reduced by 45%
• heating loads: increased by 3.9%
• heating loads are much greater than cooling loads,
so the modest increase in heating loads more than
cancels the energy savings from cooling
ies virtual environment model and components

35. building envelope glass
450000
400000
350000
300000
Load (Btu/h)
250000
200000
super high performance glass 150000
INCREASE IN HEATING LOAD
high performance glass 100000
Sun Mon Tue Wed Thu Fri Sat Sun
Date: Sun 21/Dec to Sat 27/Dec
Heating plant sensible load: 96 rooms (upgrade to solarban.aps) Heating plant sensible load: 96 rooms (base_case.aps)
heating plant sensible loads during winter solstice
- $2,457/ yr.
modeling results of super high performance glass
• results
• decrease in solar heat gain coefficient results in requirement for additional reheat
energy that more than offsets the electrical savings
• in a new england climate, with minimal summer course offerings, super high
performance glass resulted in equal or poorer performance in overall energy use
• net first cost savings to NOT use super high performance glass: $200,000

36. building facade overhangs at glass entry pavilion
1 foot overhangs
7 foot overhangs
• hypothesis
• increasing the depth of the overhangs will reduce cooling loads

37. building facade overhangs at glass entry pavilion
110000
100000
90000 SIGNIFICANT COOLING LOAD REDUCTION
80000
Load (Btu/h)
70000
60000 1 foot overhangs
50000
40000
7 foot overhangs
30000
20000
10000
0
00:00 06:00 12:00 18:00 00:00
Date: Mon 21/Jul
Cooling plant sensible load: lobby level 2 & 310A Atrium / Lounge (base_case_all_shades.aps)
Cooling plant sensible load: lobby level 2 & 310A Atrium / Lounge (base_case_no_shades.aps)
cooling plant sensible loads during single day peak time (july 21st)
21% reduction
in cooling load
7029 BTU/hr. 7 foot overhangs
8918 BTU/hr. 1 foot overhangs
cooling plant sensible loads during summer cycle
• results
• 9,804,000 BTU of cooling saved annually
• significant annual cooling cost savings to use 7 foot overhangs

38. facade and roof plant loads during peak heating periods
greenhouse – no shades Cooling load
Heating load
greenhouse glass entry
pavilion
entry lobby – horizontal shades
Heating load

39. building facade exterior shading – solar simulation model
west facing lab 301
east facing lab 314
sun path diagram –
building orientation
horizontal shade
vertical shade
“frame” climate data –
sun movement
ies software – model

40. building facade exterior shading – horizontal fins
12" deep horizontal fins
36" deep horizontal fins
• hypothesis
• increasing the depth of the horizontal fins will reduce cooling loads

41. building facade exterior shading – horizontal fins
opportunity
for
savings
WEST FACING LAB
EAST FACING LAB
annual cooling plant sensible loads (ies software generated graph)
• results
• increasing horizontal fins beyond 12ʺ resulted in very minimal electrical energy
savings due to reductions in cooling
• decreasing the amount of solar gain within the building resulted in an increase
in reheat energy, which more than offsets the electrical savings
• net first cost savings to NOT use 36ʺ deep horizontal fins: $65,000

42. building facade exterior shading – vertical fins
8" deep vertical fins
36" deep vertical fins
• hypothesis
• increasing the depth of the vertical fins will reduce cooling loads

43. building facade exterior shading – vertical fins
13000
12000
11000
10000
9000
8000
Load (Btu/h)
7000
INCREASE IN HEATING LOAD
6000
5000
4000
36ʺ vertical fins
3000
2000
8ʺ vertical fins
1000
0
00:00 06:00 12:00 18:00 00:00
Date: Tue 23/Dec
Heating plant sensible load: 301 Lab Organic (dec_vert_fins.aps) Heating plant sensible load: 314 Nursing / Indust (dec_vert_fins.aps)
Heating plant sensible load: 301 Lab Organic (dec_vert_fins_36.aps) Heating plant sensible load: 314 Nursing / Indust (dec_vert_fins_36.aps)
heating plant sensible loads (dec. 23rd)
• results
• increasing vertical fins beyond 8ʺresulted in very minimal electrical energy
savings due to reductions in cooling
• decreasing the amount of solar gain within the building resulted in an increase
in reheat energy, which more than offsets the electrical savings
• net first cost savings to NOT use 36ʺ deep vertical fins:$68,000

44. building facade exterior shading – summary data
MAY COOLING DEC HEATING
no shades no shades no shades no shades
1.899 1.669 2.272 1.357
horizontal shades horizontal shades horizontal shades horizontal shades
1.694
vertical shades vertical shades vertical shades vertical shades
horiz. and vert. shades horiz. and vert. shades horiz. and vert. shades horiz. and vert. shades
1.251 2.342 1.491
heating and cooling plant sensible loads comparing shade layouts

45. daylight harvesting ies software – radiance analysis
daylight levels (fc) 53.669 increased
percentage area 44.7 increased
above threshold (fc)

46. daylight harvesting internal light shelves
no light shelves light shelves
effective natural light penetration into space decrease in natural light penetration into space
• results
• net first cost savings to NOT use light shelves: $687,000

47. daylight harvesting windows and depth
OFF ON ON
effective natural light penetration into space
• analysis
• how deep does effective natural light penetrate into the classrooms and labs?

48. daylight harvesting windows and depth
28% of daytime lighting needs in the lab can be met with no light shelves
• results
• net savings: in 1/3 of the space, artificial lighting can be turned off through the
use of sensors to maximize natural daylight harvesting
• significantly lower operational costs

49. artificial lighting light layouts and lamping – base design (linear)
1.4 Watts/Square Foot allowable
31 fc (low)
171 fc (high)
102 fc (avg)
typical classroom at condike
base design: 3.71 W/SF
(2.31 W/SF over)
• hypothesis
• through foot candle targets modeling, first cost and energy costs can be reduced

50. artificial lighting light layouts and lamping – revised design (gridded)
• comparison
• design development layout based on electrical engineer, manufacturing data,
and architectural decisions versus prioritizing energy reduction, architectural
layouts, and "effective and even lighting" levels
8 fc (low)
54 fc (high)
27 fc (avg)
• results revised design: .94 W/SF
(0.46 W/SF under)
• effective and even lighting levels achieved with a 30%
watts per square foot lighting power density reduction
• net savings:
• first cost: $100,500
• operating costs: $10,500/year
• potential utility company incentives: $16,000/year

51. natural ventilation glass enclosed stairways
dynamic modeling of envelope, air movement, and shading
• hypothesis
• natural ventilation can provide comfort and reduce operating costs versus
a mechanical cooling system

52. natural ventilation glass enclosed stairways – improving temperatures
naturally ventilated unventilated
stair temp stair temp
improvementby
improvement by
unventilated
natural ventilation
natural ventilation stair temp
exterior temp
naturally ventilated unventilated
naturally ventilated stair temp stair temp
stair temp exterior temp
exterior temp
temperature changes in stairways throughout the school year (ies software generated graphs)

53. natural ventilation glass enclosed stairways – increasing thermal comfort
Natural ventilation reduces the
occurrence of temperatures
above 72ºF during operating
hours from more than 20% of the
time to less than 10% of the time
in the south stair.
stair temperatures by hour without natural ventilation
stair temperatures by hour with natural ventilation
• results
• elimination of 4 tons of cooling by NOT using air conditioning units
• first cost savings to naturally ventilate stairways: $34,500

54. project savings
site conditions
neighborhood hillside. . . . . . . . . . . . . . . . n/a
building envelope
glass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . $200,000
insulation – wall . . . . . . . . . . . . . . . . . . . . $12,500
insulation – roof . . . . . . . . . . . . . . . . . . . . $47,500
building facade
exterior shading – vertical fins . . . . . . . . $68,000
exterior shading – horizontal fins . . . . . . $65,000
overhang at glass entry pavilion . . . . . . . n/a
daylight harvesting
windows and depth . . . . . . . . . . . . . . . . . . n/a
internal light shelves . . . . . . . . . . . . . . . . $687,000
artificial lighting
light layouts and lamping . . . . . . . . . . . . . $100,500
natural ventilation
glass enclosed stairways . . . . . . . . . . . . . $34,500
total first cost savings . . . . . . . . . . . . . . . . . $1,500,000
total operating cost savings
. . . . . . . . . . . . $34,300 per year

55. lessons learned
1. multi disciplines should participate together
to inform low operating goals first costs
2. ʺrulesof thumbʺ and manufacturer„s data
are too general ; simulation results should
be specific to your project in your location
3. do continuous experimentation through the
design phases to maximize effective decision
making
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