Concept ETFE Rooftop Urban Farm by SYSTEMarchitects:
Natalie Jeremijenko, an aerospace engineer and environmental health professor at New York University, came up with a rooftop design to solve these common problems for urban farming. Her fixtures may be more economical than other urban farm concepts because they take up real estate that otherwise goes unused, and unlike other urban farm designs, they can pack in the plants, because everything, from the integrated systems to their bubble shape, is a slave to efficiency.
Not all roofs can support the hundreds or thousands of pounds of soil and water that a farm needs. That was a major obstacle in Viraj Puri’s hunt for a rooftop to cultivate. Puri runs Gotham Greens, a startup that’s trying to become New York City’s first commercial rooftop farming operation. Finding the appropriate site is the first thing he mentions when listing the challenges. “You have to look at the structural composition of the building and line that up with what your operations are going to be,” he says.
Jeremijenko’s design sidesteps this issue with legs. The steel stilts splayed out underneath distribute the structure’s weight to the building’s load-bearing walls. And the farms weigh less because they grow in hydroponic, soil-free trays.
The curved shape of the farms optimizes sun exposure and doesn’t require moving parts or grow lights, unlike many greenhouse designs. “The building doesn’t have to rotate to follow the sun,” says Jeremy Edmiston, principal at SYSTEMarchitects in Manhattan and co-designer of the Urban Space Station, as Jeremijenko calls the design. “There’s enough change within the shape of the building to allow for variations.”
The streamlined form also fares well on windy rooftops. A series of computer models show that decreasing wind resistance helps keep the farm intact. “The wind wants to blow the thing off the roof,” Edmiston says. “So, much of the structure is about holding it down rather than holding it up.” To get a streamlined shape, Jeremijenko’s design incorporates a skin of Ethylene tetrafluoroethylene (ETFE) stretched over curved ribs of steel. ETFE is a supertough, translucent polymer used to cover stadiums and other big spaces.
Beneath its skin, the greenhouse is linked to the building below, sharing energy, air and water. Imagine homes and offices where garden-fresh breezes waft through the vents. The breezes may do more than improve the scent. Plants cull carbon dioxide and increase the oxygen content in air, and some species can filter other harmful gases, such as formaldehyde, as well.
Besides the air, the farms would also recycle and purify gray water, which is wastewater from sinks, bathtubs and drinking fountains. Jeremijenko is experimenting with retrofits of a building’s upper two stories. They would circulate water and air through the farm and back again for people to use.