GOING BEYOND LEED: Engineering today’s green buildings into tomorrow’s climate-responsible projects
May 09, 2007
Appeared in Real Estate Weekly
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.