World’s Tallest Passive House Is Set to Open for Occupancy Fall 2017Vicki
When you’re the biggest, the tallest, the best or maybe even the “greenest”… seems everyone wants to talk about you. From its high-profile groundbreaking day in June 2016, we’ve continued to see LOTS of press on the Cornell Tech Passive House Project on Roosevelt Island in New York. Dozens of pages of articles on the topic appear when you do a Google search.
So what’s all the “buzz” about?
“The House” as it has been dubbed, is a 26-story, multi-unit building that is part of Cornell’s 2.1 million-square-foot technology campus in New York City. The Roosevelt Island Campus, which will include 350 residences for students, staff, and faculty, has been billed as the tallest (and largest) passive house in the world.
Passive House (PH) is a strict international building standard that drastically reduces energy consumption while creating a healthier, more comfortable living environment for a fraction of residents’ usual energy costs.
“Constructing the first Passive House residential high rise in the world is the latest and most exciting example of our effort to set new benchmarks in sustainability and innovation,” said Cornell Tech Dean Daniel Huttenlocher. “We hope this will serve as a model for how Passive House standards can be brought to scale in the United States and create a new template for green design here in New York City.”
Cornell Tech enlisted well-known NY developer the Hudson Companies to handle this prestigious project. Plans to achieve the Passive House standards were developed by a team of experts, including Handel Architects, Steven Winter Associates (Passive House Consultants), Buro Happold (engineers), Passive House Academy (certification), Monadnock Construction and co-owner Related Companies.
“The most exciting part of this project was the design development process with the entire team,” remarked Lois Arena, director of passive house services for Steven Winter Associates. “On a project this complex, everyone has to be brought in earlier in the process and has to work together to succeed.”
To achieve Passive House (PH) standards, Cornell Tech Residences will incorporate a number of sustainability focused design elements:
- The façade, constructed of a prefabricated metal panel system, acts as a thermally insulated blanket wrapping the building structure.
- The exterior of the southwest façade (facing Manhattan) opens to reveal a louver system that extends the entire height of the building. This system is designed to be the “gills” of the building, literally providing an enclosed, louvered exterior space where the heating and cooling equipment live, allowing the building to breathe.
- The building’s exterior shimmers, using a state-of-the-art, color-changing paint that, when reflecting light, naturally shifts color from silver to warm champagne.
- The interior spaces are designed to provide a comfortable living experience that reinforces the social and intellectual connectivity that is at the heart of Cornell’s mission and features a number of collaborative spaces, both inside and outside, to facilitate collective academic creativity.
In addition to all these glitzy design elements – the passive house has scores of equally exciting, yet more functional features as well, including its HVAC system… or should we say the LACK of an HVAC system. Passive buildings incorporate a super insulated building façade and an airtight building envelope, which will keep it warm in the winter and cool in the summer. So there was no need for a traditional HVAC system.
Instead, the building is designed with a sophisticated energy recovery ventilation (ERV) system to create a comfortable interior climate without drafts and cold spots. The ERV system constantly pulls in fresh air and removes stale air, while recovering the energy in the climate-controlled air leaving the building. Purified fresh air will be ducted into each bedroom and living room, and stale air will be exhausted from every kitchen and bathroom, thereby providing superior indoor air quality.
The ERV system starts with 2 rooftop units, each with 2 fans (1 supply and 1 exhaust) for a total of 4 fans. These 4 fans and the accompanying delivery risers and ductwork would service more than 1600 vents throughout the building. A complex system such as this requires a massive amount of individual ductwork for very little (but vital) airflow. So it became clear very early in the design process that ensuring a tight duct system would be essential to the ultimate success of the project.
According to Lois Arena, “We knew there was no way we were going to be able to get everything in this building to perform as required without sealing the ductwork. Aeroseal, was the only choice to reach the expected standards”
So, Aeroseal service provider Taitem Engineering from Ithaca, NY, was brought in to utilize the patented Aeroseal technology. “We insisted that ALL the ductwork was in place before we began,” said Aeroseal Operations Manager Evan Hallas. “Our job was make sure we sealed and tested all the ductwork from the fans on the roof all the way to the end of the duct runs. When we left the job site they knew that all their sheet metal was sealed to basically to 0% leakage, and we provided a Certificate of Performance that provided measurable and verified results.”
Airtight ductwork, coupled with the PH requirement for the airtight facade (measured as air changes per hour or ACH) provided for 0.6 ACH, ten times tighter than typical new construction. (New construction buildings average 6-8 ACH, while typical brownstones average 25 ACH.) Compared to conventional construction, the building is projected to save 882 tons of CO2 per year, equal to planting 5,300 new trees.
Considered the most rigorous energy efficiency standard in the world, PH buildings consume 60-70% less energy than typical building stock, surpassing modern standards like LEED and NYSERDA. Aeroseal was proud to play a part in the energy-savings process. Hallas noted, “In this case, it was not so much that the Aeroseal process was the energy savings measure…it was that it allowed the system to perform optimally so that the energy savings measures could be implemented”
Currently the building is in the final testing and balancing phase to ensure that there no leakage between apartments and everything is performing as expected. When the Cornell Tech Passive House opens for occupancy this fall, it will be the tallest building on Cornell Tech’s campus and an iconic marker. In addition, the PH design will offer a tremendous economic benefit for its new residents: they can expect to see this savings reflected in their electricity bills.
For More Information
For more information on the Cornell Tech Passive House project, check out this video on its unique development: