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How Buildings Breathe
A savvy mix of high technology and age-old wisdom is delivering
healthier air to indoor spaces from office complexes to concert
halls.
By Julien Devereux and Martin C. Pedersen
March 2004
Modernist architects viewed the advent of air-conditioning as a
liberation. The dissemination of the International Style relied in part
upon the ability to design a building without too much regard for
regional climate variations—and that only became possible when you
could control the climate inside. But later architecture has often taken
this reliance on climate control too far, resulting in buildings that
show no regard to energy costs or to the effects of working and living
all day in an environment without fresh air or natural light.
Fortunately some architects have begun to redress this situation and
look for ways to ventilate buildings naturally without sacrificing
aesthetics. In fact, many of the pleasing forms in the buildings
examined here came about because they aided natural ventilation. These
four buildings marry modern materials and techniques with the ancient
architectural understanding of air and heat circulation to create
healthy, energy-efficient, and beautiful “breathing buildings.” |
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Arup Campus
Solihull, England
Arup Associates
When Arup Associates decided to consolidate their Coventry and
Birmingham offices, they picked a site midway between the two cities to
average out commute times. This bit of ecological efficiency and concern
for employees is well matched in the natural ventilation system employed
in the campus buildings, which opened in January 2001.
Daniel Jang Wong, an Australian project architect with Arup, used a
canny mix of daylighting and user flexibility to greatly expand the
typical size of a naturally ventilated building. “We defied the
conventional wisdom that a naturally ventilated building’s depth
should be no greater than fifteen meters,” he says. These buildings
are 24 meters (79 feet) deep, and the roofs are crowned with distinctive
“pods,” which increase the floor-to-ceiling heights of the
rooms while allowing cross-ventilation and natural lighting. As wind
passes over the back side of the pods, it helps to draw out the hot air
that has been gathering at the top of the building, much like a pop-up
vent on the hood of a hot rod draws out engine heat.
But what makes the ventilation system especially noteworthy is the
degree of control employees have over it. “The main parts of the
windows are operated by the occupants and are designed to allow
draft-free ventilation by opening sashes at both high and low
levels,” Wong says. “This gives the occupants intuitive
control over their own local environments and contributes to the overall
environmental quality of the space, but also to a feeling of
well-being.”
Though the building was severely tested by an uncharacteristically hot
summer in 2003, it has proven to be economically efficient in some
unexpected ways. Wong notes that employee absentee rates are down by at
least 5 percent, and estimates show that the campus has saved
approximately $147,000 a year in energy costs and $130,000 a year in
maintenance. “We used pretty much standard components and fabric to
achieve our aims,” he says. “The final result gives us living
proof that designing an innovative building doesn’t necessarily
mean increasing the up-front capital expenditure.” |
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Roof pods (above and below) serve as chimneys for light and ventilation
and also provide a defining aesthetic component to the building. |
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Sensor-controlled damper devices (1) and manually operated louvers (2)
work together to let in fresh air and indirect sunlight. Protruding roof
pods (3) harness wind and allow for stack ventilation. North- and
northwest-facing roof glazing (4) directs glare-free sunlight into the
space, and windows (5) look out onto surrounding greenery. |
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Experimental Media and Performing Arts Center
Rensselaer Polytechnic Institute,
Troy, New York
Nicholas Grimshaw & Partners
How does a 1,300-seat concert hall breathe? Located on the campus of
Rensselaer Polytechnic Institute, the Experimental Media and Performing
Arts Center (EMPAC) will use a displacement ventilation system.
“The way it works is you deliver air from a low level,” says
Denzil Gallagher, an associate at Buro Happold, the project’s
consulting engineer. “It can either be from a wall or from the
floor.”
To ventilate EMPAC, the engineers place a large volume of space
underneath the seating areas—a plenum where air is stored before it
is dispersed through the audience. “The air comes out of this big
duct and gets circulated through grills under each seat in the
house,” Gallagher says. “It comes out very slowly so that
it’s equalized across the concert hall, creating a blanket of air
along the entire floor.”
As the cooler ankle-high air meets and intermingles with the audience,
it picks up heat and rises, moving slowly out of the occupied space
toward vents in the ceiling. The stage area has a separate but similar
system—except the air traveling toward the ceiling vent moves much
faster because of intense heat from the stage lights.
The system has two major advantages. Air quality is greatly improved
because the rising air carries particulates off of audience members, up
with the warming air, and out of the auditorium. Second, it is more
energy efficient than traditional overhead ventilation systems.
“With an overhead system, when you finally get the air from the top
of the concert hall down to where the audience is sitting,”
Gallagher says, “you’ve got to make it pretty cold to make it
drop through that heat layer created by the audience.” Displacement
ventilation, in contrast, uses the natural tendencies of hot and cold
air. The building, designed by Nicholas Grimshaw & Partners, broke
ground in September and is scheduled for completion in 2006.
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The rear of the main performance space projects out over one of two main
entrances. |
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From here, visitors walk alongside the glass facade (above) upstairs to
a series of bridges that link the lobby to the interior of the
beehive-shaped hall (below). |
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Inside the hall, simple thermodynamics regulate air circulation.
Cushions of cool air are pumped into the hall from separate voids
located beneath the three tiers of seats, forcing warm air to rise and
expel through ceiling vents.
This page: second from bottom, courtesy Buro Happold; all others,
courtesy Nicholas Grimshaw & Partners. |
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