Four Resilient Design Approaches Mitigating Extreme Heat Time:2022/12/29 14:50:00 Hit:116
By J.D. Harper
December 12, 2022
Avocet Tower in Bethesda, Maryland. (Cooper Carry)
New research from First Street Foundation, a nonprofit research and technology group, reveals an “extreme heat belt” will emerge in the next 30 years from Texas to Illinois, where at least one day a year, the heat index could be 125°F. Just this past year we saw what the New York Times dubbed “A summer of climate disasters,” with climate crises such as European infrastructure buckling under hazardous heatwaves and a “heat dome” that roasted the Western U.S., with temperatures soaring above 110°F.
The science tells us extreme heat will become a growing issue for more cities and we should be designing our built environment accordingly. Whenever possible, we are recommending climate-resilient design strategies to future-proof our projects for the decades to come. As it relates to extreme heat, our strategies include:
Giving the Building Shades
Since we know the hottest parts of summer are when our mechanical systems are most vulnerable, we look to ensure buildings are designed to maintain thermal comfort in the event mechanical systems are down.
At Avocet Tower, which recently received the NAIOP DC|MD Chapter Award of Excellence for Best Sustainable Project, we implemented a curtain wall glazing system called “View Glass.” The system has the ability to create shade on command and turn darker like transition lenses on sunglasses when there is extreme heat.
Embracing Passive House Principles.
A structure is defined as “passive” if it is designed to be comfortable for occupants, both in winter and in summer, without an active heating or cooling system. New construction projects have the opportunity to build passive house principles into the building design, with an emphasis on a tighter building envelope, high-performance doors and windows, and energy-recovery ventilation.
Tate Student Center at the University of Georgia in Athens, Georgia. (Cooper Carry)
As one example, our team leverages planting design and orientation to help cool buildings from the outside. We design our canopy tree placement to block solar radiation from the building and aggregate pockets of trees and shrubs to create cool microclimates near the buildings and, in particular, for spaces where people will gather. After studying wind directions and patterns, we design to channel airflow into these spaces in the warmer months of the year to maintain active airflow.
A “purple roof” at Hilton property in Columbus, Ohio. (Cooper Carry)
Mitigating the Urban Heat Island Effect
An urban heat island is a cosmopolitan area that is significantly warmer than surrounding rural areas due to human activity. In addition to orientation and material considerations, designing soft spaces in and around buildings allow for excess heat to be absorbed and gives our cities the opportunity to cool down overnight.
At a hotel we recently completed in Ohio, we incorporated an innovative vegetated roofing system that serves to absorb heat and utilizes a new technology, dubbed a “Purple Roof System.” Differing from a conventional green roof system, this “purple roof” incorporates approximately 14,000 square feet of vegetation above the grand ballroom space and works to hold and retain stormwater beyond a typical release point, acting as a detention system. Stormwater that is collected on this level, and above, is then filtered into an elevated stormwater detention vault suspended from the fifth-floor elevator lobby slab and then reused to support the cooling tower process water. This design feature played a significant role in achieving the project’s sustainability goal of LEED Gold certification.
The Foundry Apartments in Alexandria, Virginia.
In many cases, all-electric building systems are seen as cost-prohibitive, but we encourage developers to explore their options. For instance, at The Foundry in Alexandria, Virginia, we converted an empty, obsolete 13-story, 600,000-square-foot (5,574.2 sq m) government office building into a 16-story, 520-unit mixed-use residential building. The cost to add gas lines to every apartment unit was extremely costly and going all-electric was the smarter decision for the environment, construction budget, and long-term operating costs of the project.
As people who shape the future of our built environment, it is our responsibility to push the boundaries of traditional design and consider new ways of creating spaces that are resilient in the face of extreme heat. We owe it to the generations who follow us to prepare for the unprecedented climate crises to come.
J.D. HARPER, LEED AP BD+C, Fitwel Ambassador, RELi AP, and Assoc. AIA, is sustainability leader at Cooper Carry.
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