More than 35 attendees learned geothermal drilling and grouting fundamentals during the NGWA short course, Geothermal Drilling and Grouting Fundamentals, on August 29 at its headquarters in Westerville, Ohio.
In the early stages of its geothermal retrofit, NGWA took advantage of the opportunity to host the short course at a time when the geothermal market has ramped up in activity due to the tax credits extension that was passed a year ago.
Jackson Geothermal of Mansfield, Ohio, drilled a 305-foot borehole with its 2012 Versa-Drill V100 drilling rig. A 6.25-inch stabilizer with a roller bit was used to fluid drill and set 60 feet of smooth wall steel casing. After casing was installed, the remaining borehole was completed using the air rotary drilling method. The shale bedrock made a considerable amount of dust so water injection was used to control it.
After the borehole was drilled, the 1-inch SDR11 heat exchanger was installed in the borehole. The borehole was then grouted from the bottom up to the casing. Casing was then removed, and the remaining borehole was grouted to the surface using a BENSEAL and EZ-MUD® grout with a 3/4-inch tremie line.
After grouting was completed, the pressure test was removed from the 1-inch heat exchanger and a water flow test was then preformed. After the flow test was completed, the tail ends of the heat exchanger were sealed shut and cleanup of the drill site and drilling were completed.
The second half of the short course featured presenter Stuart Lyle, geothermal sales director and technical support for ISCO Industries, leading a workshop on the proper methods of thermally fusing high density polyethylene (HDPE) pipe.
A total of 20 boreholes are being drilled for NGWA’s vertical closed loop system, which will replace the Association’s outdated HVAC system that it has used since moving to its current location in September 1996.
This isn’t 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).
NGWA’s geothermal retrofit is made possible by these industry partners:
- AMTROL Inc.
- Bergerson-Caswell Inc.
- ClimateMaster Inc.
- Enertech Global LLC (GeoComfort)
- Federal Elite Heating & Cooling Inc.
- Grundfos
- Jackson Geothermal
- Preferred Pump & Equipment
- Salas O’Brien
- WaterFurnace International Inc.
- Xylem.