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Part 2: Ground-Source Heat Pump Improves School's Energy Efficiency
By Chris Matt, Associate Editor
August 2008 -
Energy Efficiency Article Use Policy
Phase II of the BEX was a 6-year, $398 million capital levy voters approved in 2001. The levy addressed the design, renovation and construction of 17 schools, including Madison Middle School.
Before its renovation, the core of the school had three parts: the original building constructed in 1925; a 1931 addition; and a gymnasium built in the 1960s. During BEX II construction, the 1925 and 1931 facilities underwent historic renovations, the gymnasium was remodeled, four portable classrooms were removed, and a one-story building West of Madison was demolished. Madison also received an addition during the project. The $37.6 million project spanned 126,800 square feet and was completed in September 2005.
“One of the main issues was mechanical and electrical,” Gillmore says. “All of the mechanical (system) was removed from the building. All the electrical (system) was removed from the building. And we rebuilt the mechanical system with a ground-source heat pump.”
The ground-source heat pump system consists of about 175 wells 300 feet deep. Each well features two 1-inch polyvinyl chloride pipes looped at the bottom. The wells are 6 inches in diameter and filled with concrete, helping the system withstand most conditions outside of an earthquake. The only parts of the system that enter the building are six hydronic pumps.
“All it takes to maintain that system is to maintain the motors on those six pumps,” Gillmore says. “That is the entire central plant for that building.”
The mechanical-system renovation significantly reduced the maintenance load at Madison because technicians do not have to maintain boilers or chillers. The ground-source heat pump has reduced Madison’s environmental footprint by 300 tons of carbon dioxide annually and has saved the district $15,000-20,000 in natural gas costs each year.
“The maintenance obligation has gone way down,” Gillmore says. “All the electrical has been redone so it’s up to standards. We’ve been increasing electrical loads due to technology (advances), so the rooms are all now wired adequately for technology for many years in the future. So maintenance will not be required to add additional circuits to rooms for technology.”
Head of the Class: Deferred Maintenance
Part 1: High-Performance Buildings: Managers Influence Design, Construction
Part 3: Sustainable School Specifies Bio-Swale, Daylighting System
Part 4: Cost Considerations for Historic Renovations