The Hearst Tower
959 Eighth Avenue
New York, NY
Jessica Lucas
Mechanical Option
The Hearst Tower
New York, NY
Presentation Outline
Introduction
Background

Background
Current System

Current System
Proposed System

Proposed System
Cost Analysis

Cost Analysis
Electrical Breadth

Electrical Breadth
Structural Breadth

Structural Breadth
Conclusions

Conclusions
Jessica Lucas
Mechanical Option
The Hearst Tower
New York, NY
Site and Location
Located along 8th Avenue between 56th & 57th
Street in Midtown Manhattan

Introduction
Background

Current System

Proposed System

Cost Analysis

Electrical Breadth

Structural Breadth

Conclusions
Constructed through the center of the original
Hearst Headquarters (1928)
Landmark building will be hollowed with new
Tower constructed through center
Jessica Lucas
Mechanical Option
The Hearst Tower
New York, NY
Project Team

Introduction
Background

Current System

Proposed System

Cost Analysis

Electrical Breadth

Structural Breadth

Conclusions
Building Owner: Hearst Corporation
Architect: Foster and Partners
Associate Architect: Adamson Associates
MEP: Flack+Kurtz
CM: Turner Construction
Jessica Lucas
Mechanical Option
The Hearst Tower
New York, NY
Size and Architecture
• 42 stories

Introduction
Background

Current System

Proposed System

Cost Analysis

Electrical Breadth

Structural Breadth

Conclusions
• 856,000 SF
• 2000 Hearst Employees
Architectural Program
• Open Office
• Auditorium
• Test Kitchens
• Television Studio
Most notable features:
• Diagrid Facade
• LEED Gold certification
Jessica Lucas
Mechanical Option
The Hearst Tower
New York, NY
Existing Mechanical System

Introduction

Background
Current System

Proposed System

Cost Analysis
Central Chilled Water Plant serving a low
temperature Variable Air Volume system
Waterside System
•
4-1000 ton cooling towers on roof level
•
2-1200 ton & 1-400 ton electric chillers in
basement chiller plant
Airside System
•
4-110,000 CFM AHU’s, serve office tower
•
Indoor Design Conditions

Electrical Breadth

Structural Breadth
• 75F for cooling/50% RH cooling

Conclusions
• 70F for heating
•
Air supplied to spaces at 45F
Jessica Lucas
Mechanical Option
The Hearst Tower
New York, NY
Proposed Mechanical System:

Introduction

Background

Current System
Proposed System

Cost Analysis

Electrical Breadth

Structural Breadth

Conclusions
Combining Steam Driven Absorption
Cooling with a Dedicated Outdoor Air/
Radiant Floor System
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
The Hearst Tower
New York, NY
Goals of Proposed System

Introduction

Background

Current System
Proposed System

Cost Analysis

Electrical Breadth

Structural Breadth

Conclusions
•
Ensure ASHRAE Std. 62.1-2004
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
Jessica Lucas
Mechanical Option
The Hearst Tower
New York, NY
Proposed Mechanical System:
Dedicated Outdoor Air System
(DOAS)

Introduction

Background

Current System
Proposed System

Cost Analysis

Electrical Breadth

Structural Breadth

Conclusions
What is DOAS?
•
100% OA unit based on ASHRAE Std.62.1
•
Decouples Sensible & Latent Loads
•
Utilizes Energy Recovery
DOAS for Hearst:
•
Std. 62.1 +30% OA for IAQ LEED point
•
Utilize an Enthalpy Wheel for total energy
recovery
•
Maintain 45F supply air temperature
Jessica Lucas
Mechanical Option
The Hearst Tower
New York, NY
Proposed Mechanical System:

Introduction

Background

Current System
Proposed System

Cost Analysis

Electrical Breadth

Structural Breadth

Conclusions
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
10.5 tons
•
Supply Air at 45F and saturation
Jessica Lucas
Mechanical Option
The Hearst Tower
New York, NY
Proposed Mechanical System:
Radiant Floor Heating and Cooling

Introduction

Background

Current System
Optimize layout based on daylighting
study using AGI32 software
Proposed System

Cost Analysis

Electrical Breadth

Structural Breadth

Conclusions
Jessica Lucas
Mechanical Option
The Hearst Tower
New York, NY
Proposed Mechanical System:
Absorption Chillers

Introduction

Background

Current System
Proposed System

Cost Analysis

Electrical Breadth

Structural Breadth

Conclusions
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
Jessica Lucas
Mechanical Option
The Hearst Tower
New York, NY
Proposed Mechanical System:
Additional Alternative

Introduction

Background

Current System
Proposed System

Cost Analysis

Electrical Breadth

Structural Breadth

Conclusions
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
Jessica Lucas
Mechanical Option
The Hearst Tower
New York, NY
Proposed Mechanical System:
Cost Analysis

Introduction

Background

Current System

Proposed System
Cost Analysis

Electrical Breadth

Structural Breadth

Conclusions
Electric
w/VAV
Total
Electricity
Total
Steam
Total
O&M
20 year
LCC
Electric
w/DOAS
Absorption
w/DOAS
$93.1 M
$41.2 M
$33.9 M
$31 M
$29.4 M
$39.4 M
$25.6 M
$14.5 M
$15.9 M
$156.4 M
$93.4 M
$98.8 M
Jessica Lucas
Mechanical Option
The Hearst Tower
New York, NY
Proposed Mechanical System:
Mechanical Summary

Introduction

Background

Current System

Proposed System
Cost Analysis

Electrical Breadth

Structural Breadth

Conclusions
Electric/DOAS
• Lowest LCC
• Lowest Operating Cost
• Higher COP
However…
• Still dependent on electric grid
• Black-outs = diminished reliability
Recommendation: Absorption/DOAS Radiant
Jessica Lucas
Mechanical Option
The Hearst Tower
New York, NY
Electrical System Breadth
Current Electrical System:

Introduction
•
4-4000 amp service take-offs

Background
•

Current System
Each takeoff is served by 1-6000 amp
service switch

Proposed System
•

Cost Analysis
Each takeoff provides 480/277 V 3
phase service from primary
transformers
Electrical Breadth

Structural Breadth

Conclusions
Daylighting & Occupancy sensors used
throughout for energy conservation
High efficiency ballasts, helped obtain rebates
from NYSERDA
Jessica Lucas
Mechanical Option
The Hearst Tower
New York, NY
Electrical System Breadth
Existing Chiller Plant

Introduction

Background

Current System

Proposed System

Cost Analysis
Electrical Breadth
Chiller 1&2: 2000 A fuses, 6 sets of 3- 400 MCM
with 1-#3/0 ground in 3”conduit
Chiller 3: 800 A fuse, 2 sets of 3-500 MCM with
1-#2/0 ground in 3.5” conduit
Cost of wiring & conduit: $932.00/LF
New Plant

Structural Breadth
Chiller 1,2,3: 40 A fuses, 1 set of 3-#6 with
1-#10 ground in 1”conduit

Conclusions
Cost of wiring & conduit: $46.80/LF
Jessica Lucas
Mechanical Option
The Hearst Tower
New York, NY
Electrical System Breadth
Existing VAV System

Introduction

Background

Current System

Proposed System

Cost Analysis
Electrical Breadth

Structural Breadth

Conclusions
8 supply fans- 124 FLA
4 return fans- 65 FLA
MCC total connected load of 1,697 FLA
Proposed DOAS System
3 supply fans- 77 FLA
3 return fans- 65 FLA
MCC total connected load of 632 FLA
Jessica Lucas
Mechanical Option
The Hearst Tower
New York, NY
Electrical System Breadth:
Conclusions

Introduction
Downsizing equipment results in:

Background
First cost savings for wire & conduits

Current System
Decreased switch sizes

Proposed System
Increased distribution board space

Cost Analysis
Allows for easier installation
Electrical Breadth

Structural Breadth

Conclusions
Jessica Lucas
Mechanical Option
The Hearst Tower
New York, NY
Structural System Breadth:
Current System

Introduction

Background

Current System

Proposed System

Cost Analysis

Electrical Breadth
Structural Breadth

Conclusions
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
Jessica Lucas
Mechanical Option
The Hearst Tower
New York, NY
Structural System Breadth:
Effect of Radiant Floors

Introduction

Background

Current System

Proposed System

Cost Analysis

Electrical Breadth
Structural Breadth

Conclusions
• International Fire Code 2003 2 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)
Jessica Lucas
Mechanical Option
The Hearst Tower
New York, NY
Structural System Breadth:
Conclusion

Introduction

Background

Current System

Proposed System

Cost Analysis

Electrical Breadth
Structural Breadth

Allowable Shear Stud Capacity greater than
Maximum shear under applied loading
Vu < ΣQn i.e. 42.8 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!
Conclusions
Jessica Lucas
Mechanical Option
The Hearst Tower
New York, NY
Conclusions

Introduction
Proposed mechanical system satisfied criteria set
forth at the beginning of the design process:
Lower annual operating costs

Background

Current System
Lessen dependence on electric grid

Proposed System
Increase reliability

Cost Analysis
Maintain Class “A” market status

Electrical Breadth

Structural Breadth
Positively impact electrical system by
lowering first cost & allowing for easier
installation

Conclusions
No nominal impact on Structural system
Obtain LEED point for IAQ
Jessica Lucas
Mechanical Option
The Hearst Tower
New York, NY
Acknowledgements
A huge Thank You to:

Introduction

Background

Current System

Proposed System

Cost Analysis

Electrical Breadth

Structural Breadth

Conclusions
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
Jessica Lucas
Mechanical Option
The Hearst Tower
New York, NY

Introduction

Background

Current System

Proposed System

Cost Analysis

Electrical Breadth

Structural Breadth

Conclusions
Questions??
Jessica Lucas
Mechanical Option