The greening of Greendale
By Sarah J. Worthman
Greendale High School is the first school in the state to heat both its hot water and pool water with solar power. The changeover should pay for itself and begin saving money in less than four years. It was made possible through assistance from the state’s Focus on Energy program, WE Energies and Johnson Controls. Many other schools and businesses have cut energy costs through these programs.
But Greendale has gone even greener by implementing a digital energy management system, timing lighting and recycling the heat that escapes from the pool’s surface. Grants from both WE Energies and Focus on Energy helped fund the pool’s thermal heating system. The total cost was just over $55,000 but Greendale paid only 30 percent, with grants from Focus on Energy ($19,343) and WE Energies ($19,343) paying the rest.
solar panels at Greendale high school
Long, black rubber strips line the outside of the roof over the pool. These strips collect the sun’s energy and heat the pool water that runs through the tubes and into five holding tanks. “A good description is that this uses the principle of laying a garden hose out in the sun,” says Brian Koffarnus, director of Food Service, Buildings and Grounds for the Greendale School District.
The system will be used April through October, and the district will use standard water heaters in colder months.
“The system uses 32 collectors pumping approximately 200 gallons of heated pool water,” he says. “The sun heats the collector water to a range of 90 to 105 degrees. The solar collectors are used to offset some of the natural gas used by the boilers.”
The total cost for the thermal hot water system was $68,000, but Greendale paid for only half, with the rest coming from grants from Focus on Energy ($16,988) and WE Energies ($16,988).
The old monster
Today, there’s an empty space where the school’s old 1976 Pacific water heater used to sit. This monstrous unit had a crack in the bottom and lost up to 3,000 gallons of water per week. Now 15 glazed solar panels sit atop the school building to harness the sun’s power and heat the school’s water.
“The glazed panels heat a glycol solution which then uses a heat exchanger to heat the domestic water,” says Koffarnus. “The panels can heat the water up to 130 degrees and will reduce the need for the boilers and natural gas.”
The greening of Greendale also has educational benefits. Terri Tessmann, a science teacher at the school, says the new heating systems can be used to teach students about solar energy. She asks students how they could create a solar powered iPod or skateboard by applying what they learn from the solar panels.
“It’s their world now,” says Tessmann. “These kids are growing up with this stuff, so I ask them, ‘how can we do this better?”
In its efforts to go green, Greendale has also made other changes: Installing T-8 energy efficient lighting and all new windows; Mounting sensors in every room so when there’s no movement, the lights automatically switch off; Installing new restroom plumbing and fixtures; Replacing all drinking fountains with energy saving models; and installing a digital energy management system to more efficiently control all lights and computers.
Greendale’s efforts have won it a Leadership Award from the Indoor Air Quality “Tools for Schools” program of the U.S. Environmental Protection Agency.
“These are real dollar savings that will increase as energy costs increase, balancing the budget in these tight fiscal times,” says Erin Green, business manager for the Greendale School District.
Focusing for over a decade
The Wisconsin Legislature started the Focus on Energy program in 1999. Since 2001, this has saved Wisconsin businesses $172 million in annual energy costs, according to Amanda Wollin, marketing manager for Focus on Energy. Between 2001 and 2008, Focus has partnered with 1,570 public and private schools in Wisconsin.
The WE Energies Website lists all these schools and offers live data recorded from the usage of their thermal energy systems.
Johnson Controls partners with Focus on Energy and has installed the new heating fixtures at many schools and organizations, including Milwaukee Area Technical College, Concordia University, Milwaukee Central Library and Outpost Natural Foods.
Greendale has signed onto Lieutenant Governor Barbara Lawton’s Energy Challenge to reduce energy use by 10 percent. The district expects to succeed. “That’s an achievable goal,” Koffarnus says.