Water Well Journal
Issue link: http://read.dmtmag.com/i/705618
"There was a large side yard associated with the site but they didn't want to use that for the loop field," Nussbaum says. "When I first saw the site, I thought this would be simple. But we ended up having to work around existing structures and some tight borders." The equipment had to be brought up ramps from the alley, and—luckily—there was enough space in the backyard to accommodate the two boreholes needed to meet the home's heating and cooling demands. The Unity Temple The project for the 16,000-square-foot Unity Temple in Oak Park, just outside of Chicago, wasn't as simple. The Temple—which is home to a Unitarian Universalist Church—was designated a National Historic Landmark in 1970, and the U.S. Department of the Interior authorized its nomination, along with 10 other Frank Lloyd Wright build- ings, for listing as a UNESCO World Heritage Site in 2014. Like the Bach House, the loop field was located in a con- fined space—this time in the front yard of the Temple, which is only about the width of the building plus 20 feet. To complicate matters, the building has irregular load patterns. It could be empty; it could be at capacity for three events in a row; or it could be somewhere in between. Nussbaum completed an initial feasibility study in 2004 to prove air conditioning could be added to the building and geothermal would work. When funding came through for the geothermal project several years later, he began from scratch on the design. He first modeled the system with nine boreholes drilled to 500 feet and traditional U-bends. "The conventional boreholes were okay, but we were a lit- tle marginal for large events," he says. "So, we remodeled it using (HDPX technology from) Rygan." Nussbaum describes the product like a "standing column system." An outer casing is put down the borehole and then an inner pipe is dropped in. Water flows down the inner pipe and around the annulus in between the outer and inner pipe and back up the hole. Lane Lawless, now the operations and project manager for Rygan Corp. in Tulsa, Oklahoma, developed the technology with Dr. Mike Fraim, who now serves as Rygan's chief scientist. They could tell neither closed-loop or open-loop geothermal systems quite fit the bill. Open-loop systems—although most efficient—required ongoing well maintenance the company was unwilling to do. Closed-loop systems require less maintenance, but there was not enough space for the number of boreholes needed. "Most of these sites are on leased space," Lawless says. "If you go a fingernail beyond a property line, they want more money." Polyethylene pipe, Lawless and Fraim believed, caused closed-loop systems to be less efficient. "It's not meant to be a good heat exchanger," Lawless is of the opinion. "It has poor heat conductivity and high thermal memory—the opposite of what you want in heat exchange— and that's the reason you don't see plastic condenser tubes." They set out to create a better closed-loop system with low thermal memory and better conductivity, but one that was still strong, sturdy, and would resist the corrosive effects of direct burial over the decades. "The only material that had a track record for doing that in really high stress direct burial applications was composite fiberglass pipe, which is the essence of what our pipe is," Lawless says. "We can specifically engineer the composite resin that goes around the glass fibers to have low thermal re- sistance. We have a material and a vessel that's, at minimum, triple the strength of poly pipe." The pipe has an epoxy joint every 20 feet and is grouted with a high density carbon backfill to get the best thermal performance. With low thermal resistance and almost no thermal mem- ory, the company claims to get 100% better performance per foot of borehole. "Theoretically, if you need 10 boreholes drilled to 500 feet, you can get by on five holes drilled to the same depth," Nuss- baum figures. "We went ahead and put in nine holes, which gives us a lot of buffer. If the saying is true, it gives us a lot of fat." Great Lakes Geothermal in West Chicago, Illinois, com- pleted the drilling and the installation of the HDPX. Eight holes went smoothly, but the weight of the grout caused the pipe to collapse downhole on the ninth hole. The Unity Temple is part of a nomination of 11 Frank Lloyd Wright buildings to be listed as a UNESCO World Heritage Site. MODERNIZING from page 23 The Emil Bach House, designed by Frank Lloyd Wright, is on the U.S. Register of Historic Places. Photo by Thad Plumley. waterwelljournal.com 24 August 2016 WWJ