Topics: Sustainability/Environment, Geothermal

June 28, 2011

James Lowe, Ball State’s director of engineering, construction and operations, inspects a portion of the green roof on top of the North District Energy Station, adjacent to the Duck Pond on McKinley Avenue.
As part of a strategic effort to incorporate environmentally conscious projects throughout campus, Ball State University has installed its first green roof on its newest building.

The university has placed about 7,000 square feet of GreenGrid — a modular, maintenance-free plant system made by Weston Solutions — on the roof of the North District Energy Station, adjacent to the Duck Pond on McKinley Avenue.

The two-story building will be one of two facilities that will pump heated and chilled water through a closed loop geothermal energy system, which is the largest in the nation. When Phase One of the geothermal project is finished this fall, the university will close down two coal-fired boilers and save more than $1 million in operating costs annually.

Construction of a second energy station, part of Phase Two, will begin in the fall. Completing Phase Two will double the monetary savings and reduce the university's carbon footprint by nearly half.

"This new green roof fits naturally into the university's long-standing commitment to the environment," said James Lowe, Ball State's director of engineering, construction and operations. "It sets the standard for the campus, since it will reduce energy needs for the new building as well as extend the life of the roof by eliminating exposure to ultraviolet light, which degrades roofing materials."

Lowe said the new roof will insulate the building and help reduce the amount of rainwater that flows into the local storm sewer system. Typically, water that hits flat surfaces such as roads and roofs picks up dirt, debris and chemicals before trickling into the nearby Cardinal Creek.

The green roof features pallets are made of 60 percent recycled plastic and filled with low-growing vegetation such as sedum, grasses, and other hearty, drought-resistant plants installed in four or five inches of soil. With a modular system, vegetation and growth media are in pallets. They come in varying sizes and are then placed on the existing roof, one after another.

Lowe said other benefits of the modular system include:

  • A green roof can reduce average daily energy demands for cooling
    by 50 percent or more compared to a typical flat roof.
  • Storm water runoff can be reduced by up to 95 percent following a 1-inch rain, lowering the impact of a building on the municipal storm drainage system and the surrounding watershed.
  • The modular design of GreenGrid systems means that roof maintenance and repairs can be performed easily as modules are simply moved to address maintenance issues and then readily put back into place.
  • Because of their light weight, removing and/or replacing selected modules can be done in just minutes with little effort.

Green roofs are common throughout Europe and have been implemented in new buildings in larger cities across North America. Chicago's city council has adopted a policy that requires green roofs to be installed on select, new buildings.

Lowe said the new green roof will nurture similar projects throughout campus as the university remodels existing buildings or constructs new facilities.

"We are going to look at installing green roofs as we move forward," he said. "The Teachers College Building is going to get a hard look even though it is 10 stories tall. Like the rest of the current buildings, we'll have to study whether it can support the system or has to be retrofitted to handle the additional weight. In future new buildings, we'll look at incorporating green roofs into our strategic construction plan."