Crews Installing 36 Miles of Geothermal Pipes to Heat/Cool Event Center
A 36-mile circuit of geothermal piping is being installed under what will be the parking lot of the County Materials Complex in Eau Claire, Wisconsin. The massive Ayres-designed event center will be heated and cooled through the geothermal system comprising a grid of 190 geothermal bore holes – each 500 feet deep and laterally spaced 20 feet from each other. A pair of polyethylene pipes descends 500 feet (through 100 feet of sand and 400 feet of bedrock) down each bore hole, connected at the bottom by a U-shaped section that allows for the liquid inside the pipe to descend down one pipe and return up the other as it circulates through the system.
The network of pipes will soon be connected inside a vault, which will be buried near the complex, and a pair of 12-inch pipes will circulate the liquid between the vault and a mechanical room inside the County Materials Complex, which consists of the 172,502-square-foot Sonnentag Events Center, the 100-yard-long John and Carolyn Sonnentag Fieldhouse, and a Mayo Clinic Health System sports medicine facility.
The 6-inch-diameter vertical bore holes are drilled through the bedrock with a studded bit driven downward by a drill rig. Grout containing bentonite and graphite is pumped into each bore hole to fill in the space around the pipes, providing conductivity and protection.
This article from the University covered construction progress as the two-year project hits the half-way point. The article describes what students in an environmental course learned about the project’s commitment to an exceptional level of sustainability.