The document discusses energy efficiency in buildings. It defines renewable and non-renewable energy sources. Renewable sources include solar, wind, and hydro power that can be replenished, while non-renewable sources like fossil fuels are finite. The document then discusses the Hearst Tower in New York City, designed by Norman Foster. It has a diagrid steel frame that uses 20% less steel. 90% of the steel is recycled. The tower achieves LEED Gold certification and uses efficient lighting and rainwater collection.

1. THE
HEARST
TOWER
ENERGY EFFICIENT BUILDINGS

2. 1Building Science
ENERGY
Energy, in building science, is a fuel or resource in building science used to operate machinery,
for heating and cooling puposes.
The sources of energy are broadly classified into two main groups: Renewable and Non-
renewable
Renewable Energy
Renewable energy is the energy which is generated from natural sources i.e. sun, wind, rain,
tides and can be generated again and again as and when required. They are available in plenty
and by far most the cleanest sources of energy available on this planet. For eg: energy that we
receive from the sun can be used to generate electricity. Similarly, energy from wind,
geothermal, biomass from plants, tides can be used to fulfill our daily energy demands
Non-Renewable Energy
Non-Renewable energy is the energy which is taken from the sources that are available on the
earth in limited quantity and will vanish fifty-sixty years from now. Non-renewable sources are
not environmental friendly and can have serious affect on our health. They are called non-
renewable because they cannot be re-generated within a short span of time. Non-renewable
sources exist in the form of fossil fuels, natural gas, oil and coal.
Efficient energy use, sometimes simply called energy efficiency, is the goal to reduce the
amount of energy required to provide products and services. For energy conservation and
efficiency, we can use several methods. They are mainly classified as:
 Active energy
 Passive energy
Energy efficiency has proved to be a cost-effective strategy for building economies without
necessarily increasing energy consumption.

3. 2Building Science
THE HEARST TOWER
Architects: Foster and Partners
Location: Midtown Manhattan, New York City,
New York, USA
Architect: Foster and Partners
Project Design: Norman Foster
Structural Engineer: WSP Cantour Seinuk
Construction: Turner Construction
Project Year: 2006
Hearst Tower is the world headquarters of
the Hearst Corporation, bringing together for the
first time their numerous publications and
communications companies under one roof,
including, among others, Cosmopolitan, Esquire
Marie Claire, Harper's Bazaar, Good
Housekeeping and Seventeen.
Hearst Tower was the first skyscraper to break ground in New York City after September 11, 2001.
The building received the 2006 Emporis Skyscraper Award, citing it as the best skyscraper in the
world completed that year. The original cast stone facade has been preserved in the new design
as a designated Landmark site. Originally built as the base for a proposed skyscraper, the
construction of the tower was postponed due to the Great Depression. The new tower addition
was completed nearly eighty years later.
The first “green” high rise office building to be completed in New York City, Hearst Tower
accurately represents the talent and intellect that drives Foster and Partners toward innovative
and ground breaking design.
The building's symmetrically jagged silhouette is easily recognizable in its surroundings. The
diagrid facade comprised of triangulated steel frame was designed to use 21% less steel than
traditional buildings of it's type. Also impressive is the statistic which states that 90% of the
10,480 tons of steel used is derived from recycled material.

4. 3Building Science
INTRODUCTION
Hearst Tower is a 46-storey office tower whose
landmark six-story cast stone base is ornamented
with columns and allegorical statues, while the
tower portions’ diagrid cladding is profiled
stainless steel and low-E clear glass. Hearst Tower
is located on 8th Avenue between 56th and 57th
Streets.
The former six-story headquarters building was
commissioned by its founder, William Randolph
Hearst, and awarded to the architect Joseph
Urban. The building was completed in 1928.
Because the building is a designated landmark
site, the original cast stone facade has been
preserved in the new. Originally built as the base
for a proposed skyscraper, the construction of the
tower was postponed due to the Great
Depression. The new tower addition was
completed nearly 80 years later. The tower—
designed by the architect Norman Foster,
developed by Tishman Speyer, and constructed by Turner Construction—is 46 stories tall,
standing 597 feet with 856,000 square feet of office space. The uncommon triangular framing
pattern (also known as a diagrid) required 10,480 tons of structural steel—20% less than a
conventional steel frame. Hearst Tower was the first skyscraper to break ground in New York City
after September 11, 2001.
A number of amenities were addded to better serve tenants, including restroom upgrades,
workstations, a wellness center, ongoing seminars and events on various health issues, the Club
(a fitness facility), Café 57 (a 340-seat corporate cafeteria), a newsstand, function spaces
(including the Joseph Urban Theater and the 44th floor), state-of-the-art technology, Studio D
(a professional photography studio), and Studio 57 (a full HD broadcast studio). All 80
conference rooms on the office floors are equipped with high-standard AV technology and are
set to “plug and play.” There is IPTV for employees to view television programming or a live
broadcast of a presentation taking place in the Joseph Urban Theater, as well as a media lab
and IT training rooms.
Located two blocks south of Central Park, the building is within walking distance of Midtown
Manhattan and all that New York City has to offer. The property is easily accessible by the
Columbus Circle subway station and several NYC Metropolitan Bus routes.

5. 4Building Science
Key Details
 First building in New York City to receive a LEED® Gold certification for New
Construction™ - Commerical Interiors™
 Diagrid frame contains roughly 20% less steel than would a conventional perimeter
frame, saving approximately 2,000 tons of steel
 Each triangle in the diagrid is four stories tall, or 54 feet
 Over 90% of its structural steel contains recycled material
 Daylight sensors control lighting and reduce energy use
 95% of office space has daylighting; 80% has views
 Over one mile of glass office fronts
 15 passenger elevators utilizing the Schindler Miconic 10 destination dispatch vertical
transportation system
 High-speed fiber-optic data transmission; fully Wi-Fi enabled
 Nine-story atrium lobby with a six-story fresco, Riverlines, and a three-story glass water
feature, Icefall
Sustainability
 LEED® Gold for Existing Buildings™
 LEED® for Existing Building: Platinum
 In 2011, Hearst Tower achieved an ENERGY STAR® score of 88. Efforts are now under
way to improve the score further by ensuring that all possible measures are being taken
to reduce energy consumption.

6. 5Building Science
The glass and steel addition sits atop a six-story cast
stone base, which was designed by Joseph Urban in 1928
at a cost of $2 million. Founded by William Randolph
Hearst, the 40,000 square feet was designated a
Landmark site during the initial designs of the addition.
The new tower stands 46 stories tall, housing 80,000
square meters of office space.
Hearst Tower entered the scene at a very important
historical moment in American history, as it was the first
skyscraper to be built after September 11, 2011. Foster
and Partners' dedication to incomparable design
becomes clearer with each project, with the Hearst
Tower receiving the 2006 Emporis Skyscraper Award as
the best skyscraper of the year in the world.
New York City’s Hearst Tower is
largely made from recycled steel and
uses rainwater for 50% of its needs

7. 6Building Science
Foster and Partners pushed the boundaries with their long list of environmental considerations
which lead to the designation of Hearst Tower as New York City's first LEED Gold certified
skyscraper. Heat conductive limestone paves the atrium floor, covering polyethylene tubing that
circulates water year round to help control the ambient temperature of the building. During the
rain, water is collected on the roof and then stored in the basement. This becomes key in the
floor tubing, irrigation, and the water sculpture in the lobby.
Icefall, the water
sculpture that reaches
three stories high, is
constructed with
thousands of glass
panels and also
contributes to the
thermal conditions of
the building by cooling
and humidifying the air
using the recycled
rainwater. Hearst Tower
remains at a comfortable
temperature for a
majority of the year by
natural ventilation.

8. 7Building Science
Another obvious way to bring down the financial and
environmental costs of the skyscraper is by optimizing the
amount of natural light flowing through the building. To
maximize the penetration of light, Foster limited the
amount of interior walls so as to block less light. Light
sensors are used to measure amounts of natural light and
react automatically depending on what is needed.

9. 8Building Science
BUILDING TECHNOLOGY
Victor Ganzi, president and CEO of PM's parent
company, Hearst, approved the tower just one
month after 9/11, committing to keep its
headquarters and 2000 local employees in New
York. The project posed a unique challenge for
British architect Norman Foster, internationally
acclaimed for graceful, modernist designs. The
contemporary skyscraper was to sit atop the
original Hearst building, a six-story 1928 art deco
landmark.
Foster's solution was to leave the limestone facade
intact, but to carve out the building's center to
create a vast atrium, and then lift the new tower
above it with huge steel-and-concrete beams. The
resulting nine-story interior, with its 30-ft.-high
waterfall and clerestory windows, promises to be one of the most dramatic spaces in New York.
"The concept," Foster says, "was to create an 'urban living room.'"
The tower's distinctive framework is a "diagrid" of interlinked triangles, so structurally efficient
that the building uses 20 percent less steel than conventional designs require. Floor-to-ceiling
windows cast light on 95 percent of the occupied space.
Thanks to dozens of energy-saving features, from motion sensors to high-efficiency ventilation
equipment, the total energy consumption of the building will be 22 percent less than that of a
typical skyscraper of comparable size-a savings of 2 million kilowatt-hours of electricity a year.
Elements throughout the building reduce the use of resources: Carpets, ceiling tiles and
furnishings were made with recycled materials; rainwater collected in 14,000-gal. tanks will
humidify the atrium. The tower is on track to become the first commercial skyscraper in New
York to receive a "gold" rating under the U.S. Green Building Council's program for Leadership in
Energy and Environmental Design.

10. 9Building Science
WATER CIRCULATION
Engineers tested the design of the lobby's 30-ft.-high waterfall using a model (above). The full-
scale version flanks both sides of the escalator, contributing to aesthetics and important building
functions. Replenished by rainwater collected on the roof, the water feature helps maintain an
ideal relative humidity of 30 to 50 percent, depending on the season, and cuts the atrium's
summer air-conditioning load by 5 percent. Water circulating through polyethylene pipes
embedded in the atrium floor provides radiant heating and cooling (below). In winter, this system
warms the granite floor to 78 F, supplying 36 percent of the atrium's heating. During the summer,
it chills the floor to 72 F, supplying 10 percent of the atrium's cooling.
GOING UP
An escalator will lead employees from the street-level entrance to the third-floor atrium level.
Manufactured in one piece, the 56-ft.-long escalator had to be hoisted into the gutted interior of
the 1928 building while the roof was off. It sat protected by plywood for more than a year before
it was installed.
Water feature

11. 10Building Science
CURTAIN WALL
The diagrid pattern intrinsic to the tower's basic construction
is traced on the exterior by stainless steel cladding. "By
expressing the structure in a sculptural way and casing it in
reflective stainless steel, it becomes the identity of the
tower," Foster says, "especially from a distance." Installing
the cladding required a custom-built, double-tier monorail
scaffold system that could move side to side as well as up and
down. Because of the building's shape, the installation of
windows proved tricky, too. "On any given floor you can have
as many as 30 different window configurations," says Syed
Alkarimi, the architectural coordinator in charge of the
facade. The double-pane glass has a low-E coating to let
visible light through while reflecting heat-causing
wavelengths. Laminate on the inner pane is twice as thick as
is typical; it should remain intact in the event of a disaster,
while the outer pane is designed to shatter.
MULTIFACETED
The 46-story edifice incorporates the original Hearst building,
finished in 1928, which was intended to support a tower that was
never built. "The challenge was to respond, at some 70 years'
remove, to the original vision of the building," Foster says. He did
so by creating a transition zone of clerestory glass that floods the
atrium with daylight. "By lifting the tower up 10 floors, we
achieved a separation from the original building, and the tower
appears to float above it." Because there are no columns on the
perimeter, the corners instead form eight-story-high "bird's
mouths." Cleaning them requires a custom-built scaffold. The
system has a raised track on the roof and articulating arms to move
the platforms in and out with the glass. "It's like a ride at
Disneyland," Borland says. Adds Alkarimi, "It's a little scarier than
that."

12. 11Building Science
BUILDING MATERIALS
The tower – designed by the architect Norman Foster is 46 stories tall, standing 182 m (597 ft)
with 80,000 m² (856,000 ft²) of office space. The uncommon triangular framing pattern (also
known as a diagrid) required 9,500 metric tons (10,480 tons) of structural steel – reportedly
about 20% less than a conventional steel frame.
The Hearst Tower has a host of features that contribute to it's gold LEED rating, including low-
emitting glass, light sensors to control the amount of artificial light used based on the amount of
natural light available from outside, high-efficiency HVAC systems, Energy Star appliances, and
the use of outside air for cooling and ventilation during 75 percent of the year. Rainwater
collection and reuse provides about half of the watering needs while also humidifying and chilling
the 10-story atrium as necessary. Low-vapor and low-
toxicity paints are used on walls and concrete surfaces, and
furnishings are formaldehyde-free. Floors and ceilings
were manufactured with recycled content and wood from
sustainable forests. The Hearst Tower is designed to be
26% more energy-efficient than a standard office building.
The tower is supported by 12 raking mega-columns.
Exterior cladding by Permasteelisa with Avesta linen-
finish stainless steel and Guardian Luxguard glass

13. 12Building Science
Exterior lighting by WE:EF; controls by Lutron
Acoustic ceilings by USG and Decoustics;
interior lighting by Zumtobel
Demountable partitions by IOC; pin-up wall by
Maharam Carnegie

14. 13Building Science
The atrium features escalators which run through a 3-story water sculpture titled Icefall, a wide
waterfall built with thousands of glass panels, which cools and humidifies the lobby air
Hearst Tower is the first green
building completed in New York City,
with a number of environmental
considerations built into the plan. The
floor of the atrium is paved with heat
conductive limestone. Polyethylene
tubing is embedded under the floor
and filled with circulating water for
cooling in the summer and heating in
the winter. Rain collected on the roof
is stored in a tank in the basement for
use in the cooling system, to irrigate
plants and for the water sculpture in
the main lobby. The building was
constructed using 80% recycled steel. Overall, the building has been designed to use 25% less
energy than the minimum requirements for the city of New York, and earned a gold designation
from the United States Green Building Council’s LEED certification program.
The atrium features escalators which run through a 3-story water sculpture titled Icefall, a wide
waterfall built with thousands of glass panels, which cools and humidifies the lobby air. The water
element is complemented by a 70-foot (21.3 m) tall fresco painting entitled Riverlines by artist
Richard Long.

15. 14Building Science
Structure
Obstructed views on the west side of the site forced the architects to move the elevator core
from the center to the west side of the building. However, by doing this, it meant that the east
side of the facade may have been left unstable and vulnerable to lateral wind forces. The
solution was either a hefty moment frame or a visually and physically lighter diagrid.
The diagrid solution reduces the total amount of steel by 20 percent (then a conventional steel
frame)while increasing structural rigidity and reducing weight. It also has the effect of allowing
40 foot spans, maximizing column, free space and permitting the elimination of corner
supports. The structure utilizes an impressive 85 percent of recycled steel.
Climate-Control System, Reflective Pavers, Low-E Glazing & Sensors
The climate control system incorporates “free air-cooling”, using filtered outside air without
temperature adjustment 75 percent of the year. Reflective pavers are utilized to increase
energy efficiency by reducing solar absorption in the in roof, while low-E coated glass ushers in
daylight without heat-producing radiation. Sensors are used throughout the building to
conserve both electricity and water.

16. 15Building Science

17. 16Building Science
ENERGY EFFICIENCY
Energy-saving features in the tower include:
 Glass coating to reduce solar radiation and therefore cooling load - the glass has a
special 'low-E' coating that allows for internal spaces to be flooded with natural light
while keeping out the invisible solar radiation that causes heat
 A limestone atrium floor with embedded polyethylene tubing for circulating water for
cooling in the summer and heating in the winter
 Sensors that control artificial light based on the amount of natural light
 Motion sensors to turn off lights and computers when an area is unoccupied
 High-efficiency heating and air-conditioning equipment that uses outside air for cooling
and ventilation for 75% of the year
 A roof that collects rainwater in a 14,000gal basement reclamation tank, which then
replaces water lost to evaporation in the office air-conditioning system and feeds into a
pumping system to irrigate plantings and trees inside and outside of the building
 The 'Icefall,' a two-storey waterfall that chills the ten-storey atrium, drawing off warm-
season heat using rainwater from the roof
 Few internal walls and low workstation partitions to maximise natural light
 Walls are coated with low-vapour paints
 Low-toxicity furniture, finishes and carpeting have content that is recycled or harvested
from sustainable forests
 Concrete surfaces are treated with low-toxicity sealants

18. 17Building Science
Site + Climate:
The building envelope was designed to limit glare from low angle sun during the early morning
and evenings.
Form + Massing:
The massing was predetermined by the footprint of the existing Hearst building. The design of
the tower, sought to protect the existing podium, whilst extending the building with a
distinctive new tower.
Passive Design:
To minimise solar gain, the building envelope contains high performance low emission glass,
with integral roller blinds which can be used to reduce glare. The building is naturally
overshadowed by the surrounding buildings so large skylights were used at the podium level to
bring daylight into the atrium space.
Environmental Systems:
The atrium contains a radiant floor, a tempered water wall and temperature controlled walls. In
the office spaces, an economiser cycle on the AHUs provide fresh air ventilation for 75% of
year.
Mobility + Connectivity:
The design included an upgrade to the local subway station, and reinstated an entrance within
the building, giving employees direct access to public transport.
Materials + Waste:
The diagrid structure uses 20 per cent less steel than a conventionally framed structure, and it
was built using 85 per cent recycled steel. Locally sourced materials are used throughout.
Water:
Harvested rainwater from the roof is fed into a central tank and used for irrigation and to feed
the water feature. This, alongside water efficient fixtures and fittings, has led to a 30%
reduction in water usage compared to a typical building.
Land + Ecology:
The design ensured that all existing trees on site were protected, and to ensure their long term
vitality, they are now irrigated through the rainwater harvesting system.
Culture + Heritage:

19. 18Building Science
The design preserved the façade of the existing structure and establishes a creative dialogue
between the old and new. The forty-two-storey tower rises above the old building and has
resulted in an award winning addition to the New York Sky Line.
Wellbeing:
At the base of the tower, there is a large atrium space for the building users. A water feature
helps enhance the microclimate by thermally tempering the space, providing acoustic
dampening and humidity control. Daylight floods the space through high level sky lights, helping
to create a healthy, vibrant space.
Prosperity:
Local construction firms were chosen where possible, to enhance the local economy. In
operation, the building has helped to regenerate the surrounding area.
Performance in Use:
First LEED Gold commercial office building in New York. Since completion it has gone on to
achieve LEED Platinum for its operation and maintenance.

20. 19Building Science

21. 20Building Science

22. 21Building Science
SUSTAINABILITY POLICY
"We can not ignore the damage that our buildings inflict on the natural environment. As the
consequences of our past inaction becomes ever more apparent, designing for a sustainable
future becomes a necessity, not a choice. Sustainable design means doing the most with the least
means. Following the logic of ‘less is more,’ it employs passive architectural means to reduce
energy consumption, minimising the use of nonrenewable fuel and reducing the amount of
pollution. Responsible sustainable design is not simply about individual buildings; it should be
implemented at all scales - from product design to the design of cities. In the final analysis,
sustainability is about good design. The higher the quality of design, and the more efficient the
project is, the longer the project will have a role, and in sustainability terms, longevity is a good
thing. The following Sustainability Policy outlines Foster + Partners’ approach to sustainable
design."
– Norman Foster

23. 22Building Science
BIBLIOGRAPHY
o www.fosterandpartners.com
o http://en.wikipedia.org/wiki/Hearst_Tower_(Manhattan)
o www.hearst.com
o www.sustainablecitiescollective.com
o www.designbuild-network.com
o www.building.co.uk
o archnet.org
o www.archdaily.com
o www.slideshare.net