The Cascade Meadow Wetlands and Environmental Science Center, located in Rochester, Minnesota, was designed to be a standing example of sustainable construction. While the facility has many features that generate energy, such as wind turbines and solar panels, it also has several features that reduce the use of energy, such as electronically tintable glass. Completed in November 2010 and opened to the public in June 2011, Cascade Meadow is a two-level, 16,000-sq.-ft. facility located on 80 acres.
Green building is also a focus for Alvin E. Benike, Inc., the Rochester, Minnesota-headquartered contractor for the Cascade Meadow project (www.benike.com). Mike Benike, Project Manager with Alvin E. Benike, has always been interested in sustainable construction, and in 2008 received his LEED accreditation.
The company is pursuing LEED Platinum certification with this project, which drove decisions to be made with energy and water conservation in mind. “There was much discussion about the types of materials to use,” Benike says. “And the primary goal of the building was energy efficiency.”
Demonstrating sustainable technologies
Because “Connecting people and communities through water, energy and sustainability education” is the mission of Cascade Meadow, sustainable construction initiatives were a priority.
“Some sustainable strategies, such as innovative stormwater management (see sidebar on next page), were undertaken for environmental reasons and not necessarily economics,” says Benike. “Other strategies, like the highly insulated building envelope and high-efficiency glazing and geothermal heating/cooling were implemented for economic payback.”
By implementing sustainable technologies, Benike expects the center to use less than half the energy of a standard, code-compliant building.
Anne Ryan, Project Architect with LHB Corp., was also involved in the design of the Cascade project. “To reduce energy, the team chose two large windows from SAGE Electrochromics, Inc.,” she explains. These windows have electronically tintable glass that can be switched from clear (if it is cloudy) to tinted (if it is sunny). “We suggested different types of glazing in the main areas based on how much sun is to be let in or how much heat is to be gained. There is more glazing facing the south to block out sun,” she says.
TPO (thermoplastic polyolefin) was also used on a few flat roofs because the material is white, which means a lower heat gain.
In partnership with Rochester Public Utilities (RPU), the Cascade Meadow site includes several key renewable energy technologies.
Solar Photo-Voltaic (electricity).
Cascade Meadow features three photo-voltaic arrays, all purchased, installed and maintained by RPU, with each demonstrating a different technology:
- PV Station 1 showcases “thin film” solar cell technology and is mounted on a rack system that tracks the sun as it moves across the sky.
- PV Station 2 also tracks the sun, but uses a more common polycrystalline solar cell technology.
- PV Station 3 has polycrystalline solar cells like Station 2, but rather than tracking the sun, the array is mounted on a rack that is adjusted based on the angle of the sun.
Wind (horizontal and vertical axis)
- RPU purchased two wind power generation technologies at Cascade Meadow — a 1kW vertical axis wind turbine (VAWT) by Urban Green Energy and a 10kW horizontal axis wind turbine (HAWT) by Bergey. The windmills, along with a solar array, account for 7.5% of the electricity produced on site.
- The horizontal turbine is mounted on a 100-ft. pole to better access consistent winds above the ground. It is expected to generate between 15,000 and 18,000 kilowatt hours (kWh) of electricity every year — which equals the energy two average Minnesota homes use per year (averaging 700 kWh per month).
- The vertical axis turbine is mounted on a 23-ft. pole and features a compact design more suitable for urban or suburban wind power generation. It is expected to generate about 750 kWh per year, which is the equivalent of about one month’s electricity for a typical Minnesota home.