Utilising the geothermal tax credits available for nonprofit organisations that were signed into law in 2022, NGWA selected Jackson Geothermal of Mansfield, Ohio, to drill 20 boreholes for a vertical closed loop system. The company drilled two test boreholes with its Versa-Drill V-100NG drilling rig in the lower level of the building's parking lot that were both set with 65ft of temporary casing.
The drilling formations encountered were: 0-2in asphalt, 2in-1ft gravel fill, 1-18ft sandy grey clay, 18-36ft coarse gravel, 36-45ft sand, 45-58ft clay and gravel, 58-65ft hard grey shale, 64-108ft light grey shale, and 108-305ft grey shale. All bedrock was dry. Jackson Geothermal drilled the top 65ft with fluid drilling, then set casing, and drilled out of the casing with air. It used a polycrystalline diamond compact (PDC) bit to drill the rock formation.
After drilling the borehole, the loop was set, the borehole was then grouted from the bottom all the way up to the bottom of the casing at 65ft. The casing was then removed, and the remainder of the hole was grouted up to the surface.
The 18 remaining boreholes are scheduled to be drilled over the next month. The vertical closed loop system will replace the Association's outdated HVAC system that it has used since moving to its current location in September 1996.
This is not the first time NGWA has supported geothermal. The Association had an open loop heat pump using a water well installed in a new building that became its headquarters in 1985 in Dublin, Ohio. Its Airport Drive building in 1995 in Columbus was fully geothermal where more than 100 boreholes were drilled by the company of long-time geothermal advocate, the late Ralph Cadwallader of Texas. There was a geothermal unit set up for training among many others (dozens).
Like at its previous headquarters, NGWA will use its vertical closed loop system to educate the industry and public about geothermal.
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