IEEE Spectrum September, 2010 - 13

4 terabits per square inch

the new record for data storage on a
ferroelectric medium. the density is about eight
times that of the most advanced magnetic hard drive, according to scientists at tohoku university, in Japan.

a pressure differential around the
tower, sending drafts ripping across
floors when workers exercise their
right to natural ventilation. "Sheets are
blowing from the tables and the doors
are smashing and the heat is going out,"
says Tom Geister, a senior architect
with Berlin-based Sauerbruch Hutton,
the firm that designed the Westarkade.
Sauerbruch Hutton worked with
Stuttgart-based firm Transsolar
KlimaEngineering to solve the
problem. The firms installed
180 vertical ventilation flaps in the
outer skin to manage air flows, creating
what they call a pressure-ring facade.
The building's control system takes
constant feedback from a rooftop
weather station and from 40 sensors
deployed throughout the building
that measure temperature, pressure,
and sunlight. The system continually
opens and closes individual flaps to
maintain a ring of consistent positive
pressure around the structure,
preventing strong winds from entering.
That should keep windows
from sabotaging the Westarkade's
high-efficiency heating and cooling
systems, which rely on such tricks
as geothermal heat exchangers, heat
captured from a basement data center,
and heat recovered from vented air.
Better still, in the fall and spring,
air from the open windows should
eliminate the need for mechanical
ventilation altogether. Throughout
the year, the control system will advise

the prevalence of feather
pecking," Roberts says.
What isn't clear yet is
whether the method will
provide an early enough
warning of future problems,
says animal behavior and
welfare researcher Bas
Rodenburg of Wageningen
University, in the
Netherlands. Fatalities in
flocks seem to result from
the tension between the
way chickens are raised and
some of their basic instincts.
spectrum.ieee.org

SEcond Skin: the Westarkade's control
system manipulates ventilation flaps on
the building facade to maintain a ring
of air pressure around the building.
photo: kfW Bankengruppe

occupants via an LED panel in offices
when open windows are a good idea,
but it gives the occupant the last word.
Of course, that's all theory.
"We will see if it works," said Axel
Hinterthan with a nervous laugh, as
he led journalists around the nearly
completed Westarkade a few months
ago. Hinterthan is director of project
management for KfW Bankengruppe,

Chicks hatched into today's
system are likely to be raised
in large numbers, in close
quarters, and with very
little training in how to be
hens, he says. Since they
can eat their fill with little
effort, their age-old instinct
to forage and peck for food
all day doesn't have an
outlet. "It's really important
to stimulate healthy foraging
early on," Rodenburg warns,
because birds who can't
forage the normal way-

which commissioned the Westarkade
as an expansion of its Frankfurt
headquarters complex. He admits
that KfW is taking a chance on new
technology to further green-building
design, which is an important role for
the state-owned development bank.
Created decades ago to implement the
Marshall Plan, KfW now administers,
among other things, low-interest federal
loans for energy-efficiency upgrades.
Transsolar engineer Björn Röhle
says his company is confident that
the pressure-ring facade is the most
efficient means of building windows
into a tower. He says that a team at the
University of Karlsruhe, in Germany,
will monitor the Westarkade's energy
consumption for two years to test
whether this approach works.
Oregon architect Perepelitza
expects that it will take two years
just to tune the Westarkade's
control systems for optimum energy
performance. He cautions that the
double-skin design was overhyped
and that some similar early projects
"didn't live up to the promise." But he is
nevertheless bullish about the pressure
ring's potential, which he says was
extensively modeled by Transsolar
and builds on the earlier designs. He
thinks it could point the way forward
for glass towers as natural ventilation
and energy efficiency grow in
importance. "This building represents
a new generation," Perepelitza says.
-Peter Fairley

by pecking the ground in
search of food-are likely to
peck at other things instead,
including their neighbors.
In recognition of these
problems, in 2012 the
European Union will outlaw
the smallest poultry cages
in favor of cages with more
room for chickens to wander
and express their foraging
instincts. But Rodenburg
notes that the trend toward
free-ranging flocks may
enable the most deranged

hens to harm more of their
coop mates. Dawkins and
Roberts, meanwhile, are
making larger-scale versions
of their system and aim to
share future detectors with
farmers and animal welfare
agencies for real-time
monitoring of other variables
and other species. "It doesn't
replace observant farmers,"
says animal scientist
Blokhuis, "but it could focus
the farmer's attention."
-Lucas Laursen

september 2010 * Ieee spectrum * NA

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Table of Contents for the Digital Edition of IEEE Spectrum September, 2010