Green roof progresses sustainability | The Triangle

Green roof progresses sustainability

In what is estimated to be one of the largest green retrofitting projects in U.S. history, a makeover of the Jacob K. Javits Convention Center is underway in New York City. The cost of the transformation is on the order of $463 million. While the effects that the green technology will have on the massive convention center and its surrounding environment are not yet known, they will be closely monitored by a team of engineers from Drexel University and The Cooper Union for the Advancement of Science and Art.

The 6.75-acre green roof is the centerpiece of a series of renovations designed to make the 27-year-old building an example of retrofitting for sustainability. When it opened in 1986, the Javits Center was, according to many architects, outdated by sustainable design measures before it even opened.


“In the last few years, the City of New York has made major commitments to sustainability and to different forms of green infrastructure,” Franco Montalto, a professor at Drexel’s College of Engineering and the team’s lead researcher, said. “The Javits Center green roof exemplifies the kind of environmentally sensible urban redevelopment projects that the City wants to encourage. The retrofit building will reduce urban runoff, mitigate the urban heat island effect, and potentially have a cooling effect on the streets and buildings that surround it. Our research will seek to quantify these benefits.”

Under the direction of FXFOWLE Epstein in New York City, a joint venture between FXFOWLE Architects and Epstein Global, the Javits Center’s major renovation project includes replacement of the building’s curtain wall, upgrades to the mechanical and electrical systems, and interior reconfigurations that will enhance the visitor experience as well as operational efficiency. These modifications are in addition to the green roof, which, at 292,000 square feet, will be the second-largest green roof on a single freestanding building in the United States.

As part of the research study, four climate stations will be installed on and around the green roof. Flumes, thermistors, soil sensors and a series of weighing lysimeters will be installed within the green roof itself. Together, these instruments will be used to evaluate what effect the green roof has on its immediate microclimate by measuring how much rainwater ultimately runs off and/or evaporates from its surface and to what extent the roof — and the intake for the convention center’s air conditioning system — is cooler once the vegetation is in place.

The design and installation of the sensor system will be led by Montalto’s research team, which is currently monitoring more than 15 other green infrastructure sites in New York, New Jersey and Pennsylvania. Students from The Cooper Union will monitor the data and use it to learn about and model functional sustainable design projects.

“The Javits Center green roof project provides Cooper Union students with a significant learning opportunity to study sustainable design and use New York City as a learning laboratory,” Joseph Cataldo, a professor in the Albert Nerken School of Engineering at The Cooper Union, said.

The students are currently developing a model that will use climate and infrared data to predict the thermal behavior of the green roof. This model will help them better understand the temperature patterns in green roofs and New York City.

“Water and energy are intimately linked through the process of evapotranspiration. Incident solar radiation changes liquid water, originally deposited on the roof by precipitation, into water vapor, which then leaves the roof surface, Montalto said. “The energy consumed by this process keeps the roof and building cooler than it otherwise would be, since without the green roof this energy would simply heat up the roof surface. At the same time, if the air in the vicinity of the air conditioner intake pipes is cooler, these units have to work less to cool the already cooler building.”

The architects at FXFOWLE Epstein predict that the renovations will decrease the center’s energy consumption by as much as 26 percent.