Well Field Developer David Lamothe, P.E.s3.amazonaws.com/ebcne-web-content/fileadmin/pres/... · 4/11/2012  · Well Field Developer David Lamothe, P.E. GZA GeoEnvironmental, Inc

Well Field Developer

David Lamothe, P.E.

GZA GeoEnvironmental, Inc

Panel Discussion: Genesis of a Geothermal Project

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Genesis of a Geothermal Project

Development of the Well Field

EBC Renewable Energy Program

Geothermal Energy Development in New England

April 11, 2012

David Lamothe, P.E., IGSHPA AI

Senior Project Manager

GZA GeoEnvironmental, Inc.

603-232-8716

david.lamothe@gza.com

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GZA and Geothermal – 3-Phase Approach

Phase I - Feasibility Study

Educate Owners

GZA w/ Energy Modeler, System Designer inputs

Recommend a ground loop type (SCW, CL, ODW)

Test well

Phase II - Design

System Designer w/ GZA input

Phase III - Installation

Driller w/ GZA observation

4

GZA and Geothermal – 3-Phase Approach

Phase I - Feasibility Study

Educate Owners

GZA w/ Energy Modeler, System Designer inputs

Recommend a ground loop type (SCW, CL, ODW)

Test well

Phase II - Design

System Designer w/ GZA input

Phase III - Installation

Driller w/ GZA observation

5

Geothermal Feasibility Study

Physical restrictions – available space for well field

Soil, bedrock, and groundwater conditions

Environmental conditions

Permitting requirements

Client’s risk tolerance – O&M, water quality

Estimated payback (typ. provide cost input to team)

6

Selection of Ground Loop

Physical restrictions – available space for well field

Closed loop closer spacing but more wells typ. required

Soil, bedrock, and groundwater conditions

Depth to rock, water quantity and quality

Environmental conditions

Soil or groundwater contamination in vicinity?

AUR/AUL?

Client’s risk tolerance to O&M, water quality issues

(Risk tolerance is often primary factor in selection)

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Ground Heat Exchanger (Ground Loop)

• Open systems (direct use of groundwater)

– Open to Diffusion Wells (ODW)

100+ feet spacing

– Standing Column Wells

75 to 100 ft on center

• Closed Loops

– Vertical wells

20 to 25 ft on center

– Horizontal

Also - Pond Loops

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Permit Considerations

State UIC registration

(Underground Injection Control)

MassDEP, RIDEM, CTDEP/CTDPH/CTDCP

More rigorous permitting for Open Loop vs. Closed Loop in Massachusetts

1 page UIC registration for CL

Open systems – UIC registration, water withdrawal reporting/registration/permitting for > 100,000 gpd (=70 gpm), [determination of non-consumptive use]

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Permit Considerations (Continued)

Open Loop

Raw Water Quality Testing Required

Selected Organics

Primary inorganics (As, nitrate/nitrite)

Radiological (Gross Alpha/Beta, Radium, Uranium)

Secondary inorganics (Na, Cl, Fe, Mn)

pH

Bacteria (total coliform [fecal and E. coli]) for discharge water

Bleed – should return to same aquifer

If > 5% to different aquifer, requires justification

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Permit Considerations (Continued)

Closed Loop

Allowed antifreeze

Propylene glycol

Ethanol

R-22/134A/407C allowed refrigerants for DX

Pipe Materials

HDPE

Fiberglass

Copper (DX Only)

Grout - Bentonite slurry/Bentonite and sand (cement allowed for DX)

11

GZA and Geothermal – 3-Phase Approach

Phase I - Feasibility Study

Educate Owners

GZA w/ Energy Modeler, System Designer inputs

Recommend a ground loop type (SCW, CL, ODW)

Test well

Phase II - Design

System Designer w/ GZA input

Phase III - Installation

Driller w/ GZA observation

12

Test Well

• Test well or “first” well of the geothermal

well field for consideration in design of

remaining well field

• Obtain site-specific geologic information

(soil, depth to and type of rock, groundwater

quantity and quality)

• Obtain thermal properties via thermal

conductivity test (CL)

• Pump test and water quality testing (SCW or

ODW)

13

GZA and Geothermal – 3-Phase Approach

Phase I - Feasibility Study

Educate Owners

GZA w/ Energy Modeler, System Designer inputs

Recommend a ground loop type (SCW, CL, ODW)

Test well

Phase II - Design

System Designer w/ GZA input

Phase III - Installation

Driller w/ GZA observation

14

Well Field Construction

• Well depth and construction

• Pressure Testing

– U-bends

– Circuits

– Headers

– Well Field

• Circuit piping Configuration

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Well Field Construction

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Well Field Construction

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Well Field Construction

• Loop photos Looping and grouting

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Well Field Construction

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Well Field Construction

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Well Field Construction

Vault construction and manifold

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Well Field Construction

Main supply and return lines

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New England Geothermal Prof. Assn.

Mission To educate and advocate for the advancement of

the Geothermal Heat Pump industry in New England to increase energy efficiency and reduce

dependency on fossil fuels

www.negpa.org

• To become part of NEGPA

Membership@negpa.org

• Information on NEGPA

Info@negpa.org