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by David Callan P.E., CEM, LEED AP, Senior Vice President, Director,
and Shreshth Nagpal, LEED® AP, Sustainability Specialist,
Sustainable
Design & High Performance
Building Technology
The low-hanging fruits are being picked. The United States Green
Building Council (USGBC)’s LEED® rating system has helped
put an inventory of sustainable strategies at our fingertips. In
fact, LEED guidelines are accepted so widely today that the USGBC
and the American Society of Heating, Refrigerating and Air-Conditioning
Engineers (ASHRAE) are writing a standard to be adopted into the
International Building Code. So, what’s next?
What
is the next level of building green?
Currently, there is a
cerebral separation between architects and engineers, and both
are to blame. While many architects are attempting to design sustainable
buildings in isolation, their engineering partners are satisfied
with plugging in whatever sustainable systems as can fit the space.
This brings up the need to drive engineers and architects together;
integrating systems design with aesthetics where we begin engineering
the architecture to create a truly high-performance facility – going
beyond LEED.
As a case
in point, consider a military utility vehicle and a midsize
hybrid car for everyday family use. The Hummer represents today’s typical energy hog of a building,
designed and built to unnecessary specifications, with disregard to the environment
and the climate surrounding it. The slapping of a sexy renewable technology
like photovoltaics or a wind turbine to illustrate “environmental consciousness” only
makes it “less bad”. In the words of Bill McDonough of William McDonough
+ Partners, “Being less bad is not being good.”
On the other hand, the Toyota Prius represents a building that
is the product of truly integrated design. With systems and materials
specified to complement the building’s environment and its function, without economically unjustified
technologies, it incorporates simple green design throughout. A building like
the Hummer will have continuing adverse impact on the environment, while a Prius-type
facility will sustain without impact for years to come. Needless to say, our
buildings should be designed and engineered like the Toyota Prius.
The next generation of green buildings must be “climate-responsive” with
careful configuration of building form and systems to take advantage of local
climate’s positive attributes and minimize its less desirable impacts.
Consider two simple dwellings, an arctic igloo and a tropical thatch hut, each
designed with regional materials to respond to the dissimilar climates appropriately.
However, “qualified professionals” today do not hesitate in building
structures with identical forms, materials and technologies no matter where it
is to be built.
So, how to go about it?
Once the site has been identified, a
climate analysis should inform the structure’s massing and orientation. The first building
element, then, to consider is the building’s envelope - the cornerstone
of climate-responsive design and indoor environmental quality. Engineers can
help architects to select materials and optimize daylight and solar control with
the up-and-coming façade technologies.
The next major component for the engineers to attack is the
M&E systems.
Typically created with “worst-case” engineering, these
are designed to perform during the building’s highest peak
demand loads. Although this is crucial, climate responsiveness
can reduce systems demands to work most efficiently at part-load
conditions. Additionally, engineers can design alternative M&E
systems including daylight controls, displacement ventilation,
radiant, chilled beam, mixed mode and natural ventilation systems
to achieve energy savings and indoor air quality to the maximum
potential.
As to how we often “miss the forest through the trees,” on
average, a building owner spends annually about $2 per square foot
in energy costs, $20 per square foot if you amortize to the cost
of constructing the building over 25 years and $200 per square
foot if you add up all of the salaries for the occupants. This
2-20-200 thumb-rule argues that by designing a climate-responsive
building that enhances indoor air quality, creates positive psychological
impacts and subsequently increases productivity by 10%, the building
pays for itself.
This kind of design, however, requires a talented and integrated
team to take conceptual sketches on paper and make them perform
in bricks and mortar. Technology itself constantly improves and
the architect’s and engineer’s collaboration comes
into play in the application of technology though design and analysis
to make the greatest impact.
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