GSHPs” co-authored by Hugh I. Henderson, Jr., P.E., Steven W. Carlson, P.E. and Adam C. Walburger of CDH Energy Corp, reported the first 12 months of monitored performance data for the ground-source hotel. They found that the pilings portion of the ground loop had better heat transfer performance than the conventional bore field. Marine Discovery Center: a Canada- Austria Collaboration. Bermingham Foundation Solutions of Hamilton, Ont., partnering with Enercret, proposed and installed a geo-exchange system to meet 100% of the cooling and heating needs of the Canadian Marine Discovery Center, opened in 2003. The building’s foundation piles also function as an energy source, providing both heating and cooling to the building. The system consists of 51 foundation piles, supplemented by 20 borehole pipes. Each circuit is then connected to a manifold in the building where heat pumps utilize the nearly constant ground temperature to provide the building’s heating and cooling. Projects in Washington State. Art Stable, an environmentally-friendly urban living/work space in Seattle, was completed in 2009. Kulchin Foundation Drilling installed the building’s geothermal foundation, inserting high-density geothermal tubes through auger-cast structural piles supporting the building. Since then, Kulchin became the first U.S. contractor to be involved in multiple energy foundation projects. In 2010, Kulchin installed its next Living Foundation™ at a lake residence near Seattle. Most recently, Kulchin teamed with GI as sub-consultant to WSP Flack & Kurtz engineers for the Federal Center South in Seattle, said Kulchin president Steve Kulchin. The Federal Center’s geothermal foundation features 45.7 cm (18 in) diameter, 45.7 m (150 ft) deep close-ended driven pipe piles. Denver Housing Authority. An 8- story LEED (Leadership in Energy and Environmental Design) Platinum Denver Housing Authority building, opened in March 2012, has heat exchanger tubes within two of its foundation piles. John McCartney, Ph.D., University of Colorado Boulder, led a research team that evaluated the energy foundations, which were coupled with a conventional GSHP system. The building has 40 boreholes, 143.3 m (470 ft) deep, for the conventional GSHP system outside the building’s footprint. The 60 foundation piles supporting the building are less than 16 m (50 ft) deep. Two of these foundation piles were “converted” into energy foundations, McCartney explained. By using the full-scale energy foundations in the Denver building, the research team could examine the typical temperature variations within the foundation, along with the thermally induced strain distributions, during typical heating and cooling operations, McCartney said. He concluded that if all of the foundations in the building had been converted to energy foundations, they could supply 10 to 20% of the building’s peak thermal loads; the back-up conventional system would be needed only during peak heating or cooling events. will cover the base heating and cooling demands on a day-to-day basis, with a conventional system to back them up during peak heating and cooling events. Demonstration of the foundations is funded by a Department of Defense environmental research program. Virginia Tech Collaborations. Virginia Tech’s Olgun, stressed the impor- tance of “university-industry collabora- tion” to answer key questions about long- term thermo-mechanical and geothermal energy pile group performance, and provide new industry design guidelines and field testing procedures. The energy foundation project at Virginia Tech involves field testing at five sites across the U.S., along with advanced numerical modeling, and technology transfer and outreach. “GI has been directly involved in this technology transfer effort,” Olgun said. “Industry participants are exchanging information about their geothermal foundation projects, as well as helping USAFA building under construction (Photo Credit: Karen Henry, U.S. Air Force Academy) U.S. Air Force Academy, Colorado Springs. McCartney is collaborator and Karen S. Henry, Ph.D., U.S. Air Force Academy, is principal investigator for an energy foundation project at the Academy. A new structure there will have 8 energy foundations 0.6 m (2 ft) in diameter and 16 m (50 ft) deep. Three different heat exchanger configurations are being evaluated in the different foundations. McCartney said the energy foundations Virginia Tech design its field studies as part of its ongoing research program.” Trevor Day School. A building for Trevor Day School, under construction in New York City, will feature 324 mm (12.75 in) diameter, ±20 m (±65 ft) deep cased displacement energy foundation piles. Olgun is overseeing instrumentation in the energy piles as part of the Virginia Tech/DFI field tests of energy pile behavior. Tom Nichols, GI Endurant’s East Coast regional DEEP FOUNDATIONS • SEPT/OCT 2012 • 85
