- Feasibility study
- Closed loop test coordination
- 80 production wells drills
- Quality assurance and control
Challenge
GZA supported the design team for geothermal in these four phases:
1) geothermal feasibility study, including conceptual wellfield design with cost estimates;
2) geothermal test well, to obtain thermal design parameters
3) geothermal wellfield design by a specialty geothermal mechanical designer;
and 4) construction, including review on contractor submittals and observation/documentation of well installation, surface piping and pressure testing.
Solution
Working with architectural firm, DiNisco Design, GZA provided engineering consulting services and performed a feasibility study of the geothermal conditions at the proposed well site located at the school’s athletic fields. GZA reviewed available hydrogeological information, applicable regulations, and permitting requirements, and published estimates of thermal capacity for bedrock at the site to prepare a conceptual well field design and solicit cost estimates form wellfield installation contractors. We recommended closed-loop wells based on regulatory requirements, overall cost, and long-term operations and maintenance requirements.
For the testing phase, GZA teamed with Skillings and Sons (S&S), a well drilling contractor, to install a test well to evaluate the drilling conditions at the site and estimate the thermal parameters for actual design of the well field. GZA’s team coordinated the drilling of a closed loop test well by S&S and conducted a 48-hour thermal conductivity test for use in obtaining site-specific information regarding drilling conditions, groundwater quality, groundwater temperature, and thermal characteristics at the site.
For the construction phase of the project, GZA provided construction oversight and engineering consulting services during the installation of 80 production wells and geothermal piping to confirm compliance with the project plans and specifications. GZA team members provided daily updates for the drilling, grouting, pipe fusion and pressure testing by the geothermal contractor.
Benefit
GZA was able to identify several quality issues during grouting and pressure testing installation that prevented potential later operational issues with geothermal system. The system was installed and is operational today.