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HVAC / Loop Contractor Partnering

HVAC / Loop Contractor Partnering. ACCA Geothermal Roundtable October 19, 2011 Nashville, Tennessee Jeff Persons, Geo Source One Inc. . Subsurface conditions play a major role in selecting the correct loop contractor for the project.

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HVAC / Loop Contractor Partnering

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  1. HVAC / Loop Contractor Partnering ACCA Geothermal Roundtable October 19, 2011 Nashville, Tennessee Jeff Persons, Geo Source One Inc.

  2. Subsurface conditions play a major role in selecting the correct loop contractor for the project

  3. Subsurface conditions can change rapidly within the same county and property

  4. Formations • Mud rotary drilling methods • High density drilling fluid helps to maintain an open bore Unconsolidated Clay Silt Sand and Gravel

  5. Formations • Sonic drilling methods • Vibrate casing to maintain an open bore for loop installation • Minimize surface debris and mud Unconsolidated Clay Silt Sand and Gravel

  6. Formations • Moist clay soils are conducive to directional boring • Minimizes surface disturbance Unconsolidated

  7. Formations • Drilled with air / mud rotary methods Soft Rock Shale Siltstone Sandstone

  8. Formations • Require down-hole hammer air-rotary drilling methods Hard rock Hard Limestone Metamorphic (Granite) Igneous (Basalt)

  9. Drilling conditions are a significantcontributor to installation cost • Stabile formations that allow for “open hole” drilling or bedrock near the surface can often allow for inexpensive skid steer mounted percussion /rotary drilling equipment

  10. A given service area may employ at least three or more drilling methods

  11. Know the subsurface conditions in your service area • Knowledge of the subsurface conditions will help focus your search for a contractor based on the type of drilling and anticipated conditions. • Sources of information: • Web search for your state’s Department of Natural Resources • Health department • Water well drilling logs • Bedrock geology • http://www.welldrilling.com/Regulatory%20Agencies_and_Industry_Associations.htm

  12. Each drilling method has an associated cost

  13. Variable drilling conditions may require partnering with more than one drilling contractor

  14. Two sources for locating accredited geothermal drilling contractors

  15. Web Links for locating an accredited geothermal vertical loop drilling contractor http://www.igshpa.okstate.edu/ http://www.ngwa.org http://www.wellowner2.org/2009

  16. Vertical Loop Installer Accreditation / certification programs IGSHPA and NGWA have jointly developed a Certified Vertical Closed Loop Driller (CVCLD) program to identify those drilling contractors who have this level of professional expertise

  17. Previous accreditation for vertical loop installers was made via the IGSHPA Accredited Installer and Vertical Loop Installer training program • Many loop installers continue to maintain their accreditation as an Accredited Installer or Vertical Loop Installer • These accreditations carry the IGSHPA designation AI and VI

  18. The Certified Vertical Closed Loop Driller (CVCLD) standard was developed to focus specifically on the drilling and grouting operations of geothermal vertical loops and for the safeguarding of the fresh water aquifers which share the same geologic strata as the vertical closed loops • Drilling contractors who are certified or are re-certifying under the new program will carry the CVCLD rating

  19. IGSHPA locate a loop installer

  20. NGWA / Wellowner.org site

  21. NGWA certified well contractors and Certified Vertical Closed Loop Design contractors (CVCLD)

  22. Survey Vertical Loop Contractors in Your Area • What credentials do they have for geothermal work • Type of equipment they operate • Conditions they are best equipped to work with; example (sand and gravel, soft rock, hard rock) • Relative cost per foot for vertical loops • Does this cost differ for the drilling conditions? • Ability to quote projects in your service area

  23. Grouting method and type of grout used • Bentonite may be fine for saturated boreholes that penetrate the water table and have excellent heat transfer with the surrounding formation. • Thermally enhanced grouts are preferred for dry hole drilling and can contain up to 75% silica sand. Sand is hard on grout pumps and adds cost to the drilling quote. (When there is no water present to enhance heat transfer, you may need to use an enhanced grout to help assure performance of the geothermal system.)

  24. Past projects that attest to the drillers experience • Ratings / reviews with BBB / Angie’s List • Ability to clean up after the drilling • Is a vacuum truck needed to prevent runoff from entering adjacent properties or the storm sewer system? • Who will notify the utility location services • Who will identify the location of sanitary fields and sewer lines?

  25. Does the drilling contractor have Workers’ Compensation insurance? • General Liability insurance? • Is a permit required for drilling in your area? • If so, who is responsible for the permit purchase and filing?

  26. Question and Answer A full text of questions for consideration when selecting a vertical loop contractor is found in the accompanying hand-out or on line at www.wellowner.org

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