1. The Hearst Tower 959 Eighth Avenue New York, NY
Jessica Lucas
Mechanical Option

2. The Hearst Tower New York, NY
Presentation Outline
Introduction
Background
Current System
Proposed System
Cost Analysis
Electrical Breadth
Structural Breadth
Conclusions
Background
Current System
Proposed System
Cost Analysis
Electrical Breadth
Structural Breadth
Conclusions
Jessica Lucas
Mechanical Option

3. The Hearst Tower New York, NY
Site and Location
Located along 8th Avenue between 56th & 57th Street in Midtown Manhattan
Constructed through the center of the original Hearst Headquarters (1928)
Landmark building will be hollowed with new Tower constructed through center
Introduction
Background
Current System
Proposed System
Cost Analysis
Electrical Breadth
Structural Breadth
Conclusions
Jessica Lucas
Mechanical Option

4. The Hearst Tower New York, NY
Project Team
Building Owner: Hearst Corporation
Architect: Foster and Partners
Associate Architect: Adamson Associates
MEP: Flack+Kurtz
CM: Turner Construction
Introduction
Background
Current System
Proposed System
Cost Analysis
Electrical Breadth
Structural Breadth
Conclusions
Jessica Lucas
Mechanical Option

5. The Hearst Tower New York, NY
Size and Architecture
42 stories
856,000 SF
2000 Hearst Employees
Introduction
Background
Current System
Proposed System
Cost Analysis
Electrical Breadth
Structural Breadth
Conclusions
Architectural Program
Open Office
Auditorium
Test Kitchens
Television Studio
Most notable features:
Diagrid Facade
LEED Gold certification
Jessica Lucas
Mechanical Option

6. The Hearst Tower New York, NY
Existing Mechanical System
Central Chilled Water Plant serving a low temperature Variable Air Volume system
Waterside System
ton cooling towers on roof level
ton & ton electric chillers in basement chiller plant
Airside System
4-110,000 CFM AHU’s, serve office tower
Indoor Design Conditions
75F for cooling/50% RH cooling
70F for heating
Air supplied to spaces at 45F
Introduction
Background
Current System
Proposed System
Cost Analysis
Electrical Breadth
Structural Breadth
Conclusions
Jessica Lucas
Mechanical Option

7. The Hearst Tower New York, NY
Proposed Mechanical System:
Combining Steam Driven Absorption Cooling with a Dedicated Outdoor Air/ Radiant Floor System
Introduction
Background
Current System
Proposed System
Cost Analysis
Electrical Breadth
Structural Breadth
Conclusions
Replace electric chillers with double effect steam driven absorption
Replace the central VAV AHU’s with dedicated outdoor air (DOAS) units
Install radiant floors to parallel DOAS for both heating & cooling
Jessica Lucas
Mechanical Option

8. The Hearst Tower New York, NY
Goals of Proposed System
Ensure ASHRAE Std
compliance
Obtain the LEED point for IAQ
Lessen the Tower’s dependence on an
overextended electric grid
Lower annual operating cost
Meet the original criteria to create a reliable Class “A” office building
Introduction
Background
Current System
Proposed System
Cost Analysis
Electrical Breadth
Structural Breadth
Conclusions
Jessica Lucas
Mechanical Option

9. The Hearst Tower New York, NY
Proposed Mechanical System:
Dedicated Outdoor Air System
(DOAS)
What is DOAS?
100% OA unit based on ASHRAE Std.62.1
Decouples Sensible & Latent Loads
Utilizes Energy Recovery
DOAS for Hearst:
Std % OA for IAQ LEED point
Utilize an Enthalpy Wheel for total energy recovery
Maintain 45F supply air temperature
Introduction
Background
Current System
Proposed System
Cost Analysis
Electrical Breadth
Structural Breadth
Conclusions
Jessica Lucas
Mechanical Option

10. The Hearst Tower New York, NY
Proposed Mechanical System:
The resulting DOAS Design:
3-40,000 CFM Semco units with a molecular sieve desiccant coated enthalpy wheel
Chiller plant downsized by 30%
Cooling coil load decreased from 44 tons to tons
Supply Air at 45F and saturation
Introduction
Background
Current System
Proposed System
Cost Analysis
Electrical Breadth
Structural Breadth
Conclusions
Jessica Lucas
Mechanical Option

11. The Hearst Tower New York, NY
Proposed Mechanical System:
Radiant Floor Heating and Cooling
Optimize layout based on daylighting study using AGI32 software
Introduction
Background
Current System
Proposed System
Cost Analysis
Electrical Breadth
Structural Breadth
Conclusions
Jessica Lucas
Mechanical Option

12. The Hearst Tower New York, NY
Proposed Mechanical System:
Absorption Chillers
3-600 ton Double-effect chillers arranged in parallel
Lithium Bromide/Water- no CFC’s or HCFC’s
New chiller plant requires 60 kW of electric input, compared to 1,941 kW used in the electric chiller plant
Con Edison offers incentives for steam driven cooling during the cooling season
Introduction
Background
Current System
Proposed System
Cost Analysis
Electrical Breadth
Structural Breadth
Conclusions
Jessica Lucas
Mechanical Option

13. The Hearst Tower New York, NY
Proposed Mechanical System:
Additional Alternative
Can I save even more with an Electric Chiller Plant w/DOAS System?
Still 30% reduction in chiller plant size
Still only minimum CFM
Higher COP with vapor compression cycle
Introduction
Background
Current System
Proposed System
Cost Analysis
Electrical Breadth
Structural Breadth
Conclusions
Jessica Lucas
Mechanical Option

14. The Hearst Tower New York, NY
Proposed Mechanical System:
Cost Analysis
Electric w/VAV
Electric w/DOAS
Absorption w/DOAS
Total Electricity
$93.1 M
$41.2 M
$33.9 M
Total Steam
$31 M
$29.4 M
$39.4 M
Total O&M
$25.6 M
$14.5 M
$15.9 M
20 year LCC
$156.4 M
$93.4 M
$98.8 M
Introduction
Background
Current System
Proposed System
Cost Analysis
Electrical Breadth
Structural Breadth
Conclusions
Jessica Lucas
Mechanical Option

15. The Hearst Tower New York, NY
Proposed Mechanical System:
Mechanical Summary
Electric/DOAS
Lowest LCC
Lowest Operating Cost
Higher COP
However…
Still dependent on electric grid
Black-outs = diminished reliability
Recommendation: Absorption/DOAS Radiant
Introduction
Background
Current System
Proposed System
Cost Analysis
Electrical Breadth
Structural Breadth
Conclusions
Jessica Lucas
Mechanical Option

16. The Hearst Tower New York, NY
Electrical System Breadth
Current Electrical System:
amp service take-offs
Each takeoff is served by amp service switch
Each takeoff provides 480/277 V 3 phase service from primary transformers
Daylighting & Occupancy sensors used throughout for energy conservation
High efficiency ballasts, helped obtain rebates from NYSERDA
Introduction
Background
Current System
Proposed System
Cost Analysis
Electrical Breadth
Structural Breadth
Conclusions
Jessica Lucas
Mechanical Option

17. The Hearst Tower New York, NY
Electrical System Breadth
Existing Chiller Plant
Chiller 1&2: 2000 A fuses, 6 sets of MCM with 1-#3/0 ground in 3”conduit
Chiller 3: 800 A fuse, 2 sets of MCM with 1-#2/0 ground in 3.5” conduit
Cost of wiring & conduit: $932.00/LF
Introduction
Background
Current System
Proposed System
Cost Analysis
Electrical Breadth
Structural Breadth
Conclusions
New Plant
Chiller 1,2,3: 40 A fuses, 1 set of 3-#6 with 1-#10 ground in 1”conduit
Cost of wiring & conduit: $46.80/LF
Jessica Lucas
Mechanical Option

18. The Hearst Tower New York, NY
Electrical System Breadth
Existing VAV System
8 supply fans- 124 FLA
4 return fans- 65 FLA
MCC total connected load of 1,697 FLA
Introduction
Background
Current System
Proposed System
Cost Analysis
Electrical Breadth
Structural Breadth
Conclusions
Proposed DOAS System
3 supply fans- 77 FLA
3 return fans- 65 FLA
MCC total connected load of 632 FLA
Jessica Lucas
Mechanical Option

19. The Hearst Tower New York, NY
Electrical System Breadth:
Conclusions
Downsizing equipment results in:
Introduction
Background
Current System
Proposed System
Cost Analysis
Electrical Breadth
Structural Breadth
Conclusions
First cost savings for wire & conduits
Decreased switch sizes
Increased distribution board space
Allows for easier installation
Jessica Lucas
Mechanical Option

20. The Hearst Tower New York, NY
Structural System Breadth:
Current System
Half of the foundation is supported by
spread footings, half by caissons
Primary lateral support provided by the
perimeter Diagrid
Secondary lateral system defined by braced
frame at the service core
Structure below 10th floor
uses a mega-column system
to support a large unbraced
height
Introduction
Background
Current System
Proposed System
Cost Analysis
Electrical Breadth
Structural Breadth
Conclusions
Jessica Lucas
Mechanical Option

21. The Hearst Tower New York, NY
Structural System Breadth:
Effect of Radiant Floors
International Fire Code hour fire
rating
Vulcraft Deck 6” slab
Radiant tubes 1.5” concrete cover
Check deck, beams, girders with additional
concrete load
LRFD Manual example for
Composite W-shape flexural member design (unshored construction)
Introduction
Background
Current System
Proposed System
Cost Analysis
Electrical Breadth
Structural Breadth
Conclusions
Jessica Lucas
Mechanical Option

22. The Hearst Tower New York, NY
Structural System Breadth:
Conclusion
Allowable Shear Stud Capacity greater than
Maximum shear under applied loading
Vu < ΣQn i.e k < 451 k
Allowable Flexural Capacity exceeds
Maximum moment under the applied
factored loading
Mu < ФMn i.e. 428 ft-k < 450 ft-k
No changes needed to member sizes!
Introduction
Background
Current System
Proposed System
Cost Analysis
Electrical Breadth
Structural Breadth
Conclusions
Jessica Lucas
Mechanical Option

23. The Hearst Tower New York, NY
Conclusions
Proposed mechanical system satisfied criteria set forth at the beginning of the design process:
Lower annual operating costs
Obtain LEED point for IAQ
Lessen dependence on electric grid
Increase reliability
Maintain Class “A” market status
Positively impact electrical system by lowering first cost & allowing for easier installation
No nominal impact on Structural system
Introduction
Background
Current System
Proposed System
Cost Analysis
Electrical Breadth
Structural Breadth
Conclusions
Jessica Lucas
Mechanical Option

24. The Hearst Tower New York, NY
Acknowledgements
A huge Thank You to:
JJ, Dr. Freihaut, Dr. Bahnfleth, Dr. Mumma,
Dr. Srebric and the rest of the AE Faculty.
My fellow classmates especially Jenny, Jayme,
Yulien, Dave, Bryan, and Adam.
Paul Reitz of Flack+Kurtz
Introduction
Background
Current System
Proposed System
Cost Analysis
Electrical Breadth
Structural Breadth
Conclusions
Jessica Lucas
Mechanical Option

25. The Hearst Tower New York, NY
Introduction
Background
Current System
Proposed System
Cost Analysis
Electrical Breadth
Structural Breadth
Conclusions
Questions??
Jessica Lucas
Mechanical Option