Attch 24iii. Coburn Gore Final Geothermal Study 2025 09 06.pdf
PDF 6 MB Posted
- Solicitation number
- 47PB0025R0044
About this file
This document is a Geothermal Feasibility Report for the Coburn Gore Land Port of Entry (LPOE) in Maine, prepared for the U.S. General Services Administration (GSA). The report details a comprehensive geothermal system assessment for a new facility, which includes constructing a new main building, renovating the historic main building, and relocating four existing residences. The geothermal approach involves a vertical closed-loop system utilizing two test boreholes drilled to 500 feet, with thermal conductivity testing revealing formation temperatures around 47.4-48.4°F and thermal conductivity between 1.33-1.37 Btu/hr-ft-F.
The proposed geothermal system is estimated to require up to 16,300 linear feet of vertical bores across multiple buildings, with 15 vertical bores for the new main building, 10 bores for the historical building renovation, and 2 bores each for the four relocated residences. Peak heating and cooling loads were calculated using Trane's Trace 700 modeling software, with the new main building requiring 306.4 MBH of heating and 19.4 tons of cooling. The report recommends using a Certified Geo-Exchange Designer to finalize the system design and notes that the geothermal installation will need to comply with Maine Department of Environmental Protection regulations and meet specific setback requirements for the existing on-site well.
View the file
Other files
Show all 50
On GovTribe
Work with this file
- Download the original file
- Contacts named in this file
- Similar government files
- Ask GovTribe AI about this file
Text version
September 6, 2024 Final Report PDN Number: EP-47PB0022F0053
COBURN GORE LAND PORT OF ENTRY (LPOE)
COBURN GORE, MAINE
Prepared For: Prepared By:
General Services Administration Thomas P. O’Neill, Jr., Federal Building 10 Causeway Street, Room 1100 Boston, MA 02222
Coburn Gore Land Port of Entry (LPOE) Geothermal Feasibility Study
PROPERTY OF THE UNITED STATES GOVERNMENT. COPYING,
DISSEMINATION, OR DISTRIBUTION OF THESE DRAWINGS AND/OR
DOCUMENTS WITHOUT THE EXPLICIT PERMISSION OF THE
U.S.GENERAL SERVICES ADMINISTRATION IS PROHIBITED.
DISTRIBUTION TO THOSE WITH OTHER THAN A NEED TO KNOW IS
STRICTLY FORBIDDEN.
285.082.002 – Needs Assessment Report September 6, 2024
COBURN GORE LAND PORT OF ENTRY (LPOE), MAINE
Geothermal Feasibility Report
PROPERTY OF THE UNITED STATES GOVERNMENT
FOR OFFICIAL USE ONLY
Contents
EXECUTIVE SUMMARY 2
Introduction and Overview of the Project 2
Coburn Gore LPOE, Coburn Gore, ME 2
Geothermal Solution Approach 3
Due Diligence 3
Bedrock Geology 3
Surficial Geology 4
Hydrologic 5
Drilled Wells 6
Oil and Hazardous Spill, Remediation Sites 8
Geothermal Recommendations 10
Geothermal System Type 10
Geothermal System Scale 11
Other Geothermal Considerations 12
Data Gathering Approach 14
Permits/Regulatory 15
Environmental Impacts 16
APPENDICES
Appendix A: Main Building Preliminary Geothermal Sizing Appendix B: New Main Building Preliminary Geothermal Sizing Appendix C: 1932 Residence Preliminary Geothermal Sizing Appendix D: 1967 Residence Preliminary Geothermal Sizing Appendix E: Ground Source Heat Exchange Evaluation Report CG-GTB-1 Appendix F: Ground Source Heat Exchange Evaluation Report CG-GTB-2
285.082.002 – Needs Assessment Report September 6, 2024
Geothermal Feasibility Report
PROPERTY OF THE UNITED STATES GOVERNMENT
FOR OFFICIAL USE ONLY
EXECUTIVE SUMMARY
Introduction and Overview of the Project Colby Company has prepared this Geothermal Feasibility Report for the U.S. General Services Administration (GSA). The objective of this study is to define the geothermal situation at the Coburn Gore LPOE, along with the development of possible alternatives, and ultimately the selection of a preferred alternative based on this information.
This report also includes a full evaluation of the existing property, along with the sizing loads of the preferred building alternative that was noted in the Parsons feasibility study dated November 29, 2018, including the addition of an entirely new facility to be located on the north side of State Route 27.
Coburn Gore LPOE, Coburn Gore, ME The Coburn Gore LPOE is located in Coburn Gore, ME, a small unorganized township in Franklin County.
Coburn Gore is an isolated setting about 20 miles northwest of the small town of Eustis, Maine. Coburn Gore is across the border from Woburn, Quebec. The LPOE consists of a Main Building and four stand-alone residences on 3.6 acres of property; which straddle both sides of State Route 27. See Figure 1 for a map showing the location of the Coburn Gore LPOE.
(Figure 1.)
285.082.002 – Needs Assessment Report September 6, 2024
Geothermal Feasibility Report
PROPERTY OF THE UNITED STATES GOVERNMENT
FOR OFFICIAL USE ONLY
Geothermal Solution Approach The geothermal approach of this needs assessment is to outline the geothermal situation at the Preferred Alternative in the Parsons ‘Feasibility Study LPOE Coburn Gore, Coburn Gore, ME’ report dated 29 November 2018. The intent is to understand the suitability of an Earth-coupled geothermal system as a ground-coupled heat source-sink for HVAC heating and cooling. The Preferred Alternative, Alternative 3b, consists of the following main items of interest related to a geothermal system:
● Land acquisition
● Construction of a new Main Building
● Renovation and conversion of Historic Main Building into Relief Quarters
● Construction of new hotel style housing for 10 officers with common spaces for kitchen recreation, and health and wellness
● Relocation of four Historic GSA residences
The new LPOE facility is intended to be located on the existing site and the land acquisition which abuts the existing LPOE property to the South, East and North. There will be a mix of existing, relocated and new buildings. This needs assessment will focus on the geologic and environmental review and suitability, preferred earth-coupling method, and scale of potential earth-coupling geothermal designs.
Due Diligence Various geologic, hydrologic, and environmental resources were researched for the project site and surrounding area. This information as a whole assists in determining the most viable and realistic geothermal earth-coupling method. Information was obtained online via the Maine Department of Environmental Protection (DEP), Bureau of Remediation and Waste Management and the Maine Department of Agriculture, Conservation & Forestry, Maine Geological Survey (MGS). See summary below.
Bedrock Geology The MGS’s Bedrock Geologic Map of Maine shows that the underlying bedrock at the project site is labeled D1 (see Figure 2). It is described as granite rock from the Devonian period.
285.082.002 – Needs Assessment Report September 6, 2024
Geothermal Feasibility Report
PROPERTY OF THE UNITED STATES GOVERNMENT
Figure 2
Surficial Geology The MGS’s Surficial Geologic Map of Maine shows that the overburden deposits at the site are labeled ‘go’, consisting of sand and gravel glacial outwash deposits. See Figure 3.
285.082.002 – Needs Assessment Report September 6, 2024
Geothermal Feasibility Report
PROPERTY OF THE UNITED STATES GOVERNMENT
Figure 3
Hydrologic The site is located within a significant aquifer of 10-50 gallons/min. There is a public water supply well at the site. See Figure 4 for Maine DEP mapping of the site.
285.082.002 – Needs Assessment Report September 6, 2024
Geothermal Feasibility Report
PROPERTY OF THE UNITED STATES GOVERNMENT
Figure 4
Drilled Wells Information on nearby wells was collected from the MGS Well Database and the Maine DEP Drinking Water Program to understand various subsurface conditions near the site. As noted above, there also is a public water supply well at the site, which is at a depth of 325 ft. More information on this well was
285.082.002 – Needs Assessment Report September 6, 2024
Geothermal Feasibility Report
PROPERTY OF THE UNITED STATES GOVERNMENT
FOR OFFICIAL USE ONLY
not obtained. One nearby well was found about 1000 ft to the East of the site (see Figure 5). Pertinent information on the two wells can be found in Table 1.
Based on the well information collected, the following observations were made:
● overburden thickness (soils on top of bedrock) was 45 ft for the nearby well
● well depths ranged from 160 to 325 ft
● water yield was 6 gpm for the nearby well
● water static levels were not available
See Appendix A for detailed information on the two thermal test wells that were installed at the site in July 2024. The test bores were installed to the full anticipated depth of 500 ft. Notably, bore 2 encountered cobbles and boulders above bedrock which allowed hole collapse, so methods were changed to utilize casing advance system. Both bores encountered bedrock at between 22 and 33 ft below ground surface, and during drilling an estimated 0.25 to 15 gpm of water production was encountered.
Table 1
285.082.002 – Needs Assessment Report September 6, 2024
Geothermal Feasibility Report
PROPERTY OF THE UNITED STATES GOVERNMENT
Figure 5
Oil and Hazardous Spill, Remediation Sites The Maine DEP Bureau of Remediation and Waste Management online maps and data revealed that there are multiple reported Oil and Hazardous Spill Sites, no Remediation Sites, and one closed solid waste landfill at or within 1000 ft of the project site. However, the site has a public water supply well and the other nearby water well is within 350 ft of the closed landfill. See Figure 6.
● Spill A-235-2006 notes alleged drums of agent orange buried behind border station on boundary line
● Other spills are diesel or gasoline
285.082.002 – Needs Assessment Report September 6, 2024
Geothermal Feasibility Report
PROPERTY OF THE UNITED STATES GOVERNMENT
Figure 6
285.082.002 – Needs Assessment Report September 6, 2024
Geothermal Feasibility Report
PROPERTY OF THE UNITED STATES GOVERNMENT
FOR OFFICIAL USE ONLY
Geothermal Recommendations
Geothermal System Type There are several methods of installing geothermal systems. The best system for a particular site can vary depending on multiple factors, including geology, hydrology, available space near the buildings, and depth to bedrock. The due diligence research in the previous section reveals the following:
● The type of bedrock, the surficial geology, and hydrology at the site do not reveal any significant concerns about installing any geothermal system type other than utilizing a casing advance system to prevent overburden borehole collapse.
● Wells on or near the site indicate bedrock depths, water yields, and static water levels that are good candidates for installing a geothermal system.
● Though there are multiple documented Spill Sites at or within 1000 ft of the existing LPOE site, there are no Remediation Sites on or within 0.25 miles of the site. The Spill Sites for diesel and gasoline spills indicate minimal anticipated issues for installing a geothermal system. It is unknown what impact the ‘alleged’ buried agent orange barrels may pose.
● The closed landfill that is within 1000 ft of the site has minimal potential contamination issues for a geothermal system since there is a domestic water well within 350 ft of the closed landfill, and there is a public water supply well on the site.
Closed-loop geothermal systems are the most prevalent in non-residential buildings. They are comprised of a network of pipes in the ground, and the heat transfer fluid pumped through the piping remains fully within the piping.
Open systems pump actual ground water from a water producing well through the geothermal heat pumps, then return the water back to the ground. Open systems are popular with single family residences that have a water well that supplies the domestic water needs, and can use the same well for geothermal heating and cooling. Open systems are subject to the water chemistry and sedimentation that occur in the well, which can have excessive maintenance issues that are typically not desired. It is difficult to evaluate the water chemistry and sedimentation aspects at the site without extensive costs relative to the size of the buildings and the geothermal system, so pursuing an open geothermal system is not recommended.
Closed-loop geothermal can be installed either with horizontal piping buried 6 to 10ft deep, or with vertical boreholes drilled into bedrock hundreds of feet deep. The thermal properties of the horizontal system type in Northern Maine, combined with much larger surface area and possibly stones and boulders, makes that configuration not desirable for the project site.
285.082.002 – Needs Assessment Report September 6, 2024
Geothermal Feasibility Report
PROPERTY OF THE UNITED STATES GOVERNMENT
FOR OFFICIAL USE ONLY
Therefore, the recommended type of geothermal system for the project site is a vertical closed-loop system.
The vertical closed-loop test boreholes installed at the site confirmed the viability of installing a vertical closed-loop geothermal system and provided pertinent information to consider in designing a geothermal system to meet the heating and cooling needs of the facility. See the full test well report in Appendix A for details and a summary of the main considerations below.
● The test bores were successfully installed to the target depth of 500 ft.
● Bedrock was at 22 and 33 ft below ground surface at the test bore locations. These depths, if they are somewhat consistent across the site, would keep the casing costs to a minimum
● A relatively low water production of 0.25 to 15 gpm was encountered during drilling, which was able to be managed successfully during installation. If other bores encounter similar amounts of water production, the water management efforts and costs should be minimal.
● Thermal properties were measured as follows for the installed 500 ft deep test boreholes
○ Thermal conductivity 1.33 to 1.37 Btu/hr-ft-F
○ Thermal diffusivity 0.71 to 0.73 ft^2/day
○ Undisturbed formation temperature 47.4 to 48.4 F
Geothermal System Scale The geothermal system scale is directly related to the heating and cooling loads of the building(s) being conditioned. For this study, the preliminary sizing of a closed-loop vertical geothermal system was estimated based on the anticipated peak heating and cooling loads. For the Preferred Alternative, the peak loads are estimated at the following:
New Main Building:
● 19.4 tons of cooling
● 306.4 MBH of heating
Main Historical Building Renovation:
● 11.1 tons of cooling
● 204 MBH of heating
1932 Residences (each of 2 units)
● 1.5 tons of cooling
● 30 MBH of heating
285.082.002 – Needs Assessment Report September 6, 2024
Geothermal Feasibility Report
PROPERTY OF THE UNITED STATES GOVERNMENT
FOR OFFICIAL USE ONLY
1967 Residences (each of 2 units)
● 1.75 tons of cooling
● 35 MBH of heating
The resultant closed-loop vertical geothermal system needed to support these peak loads is estimated to require up to 16,300 lineal feet of vertical bore total for all buildings, with each bore being in the range of 450 to 500 ft deep and spaced 20 ft apart (see Appendix B for assumptions and results of geothermal system sizing software). This preliminary geothermal borefield system sizing resulted in 15 vertical bores for the New Main Building, 10 bores for the Main Historical Building Renovation, and 2 bores for each of the 4 relocated residences. These bores would need to be connected to each building with horizontal piping. (Note that the installed test bore was installed with 1.25 inch diameter HDPE piping, but the preliminary sizing resulted in the bores needing 1.0 inch piping. This will need to be considered in the final geothermal design.)
Other Geothermal Considerations The horizontal piping connecting the vertical closed-loop boreholes should be installed below expected freezing depths, or about 9ft deep. The geothermal bores and piping would need to be coordinated with other site features, such as underground utilities. Also, the geothermal system would need to meet all applicable setbacks, specifically for the existing well on site. The Maine Well Drillers Rules have specific setbacks for closed-loop geothermal for the borehole wells, see Figure 7.
285.082.002 – Needs Assessment Report September 6, 2024
Geothermal Feasibility Report
PROPERTY OF THE UNITED STATES GOVERNMENT
Figure 7
The final locations of geothermal bores and the piping system will need to be carefully coordinated during the design phase for the building. It appears that there is adequate area for the estimated bores at 20 ft separation near each of the buildings. The bore locations and underground piping details will also need to be coordinated with other site improvements for the new parcel of land and the final site plans.
A Certified Geo-Exchange Designer (CGD) should design the geothermal earth-coupling systems to ensure the best design and highest performance of the geothermal system. The heating and cooling peak loads, as well as estimates for annual energy, must be determined by the final design engineers/designers based upon the actual building updates.
285.082.002 – Needs Assessment Report September 6, 2024
Geothermal Feasibility Report
PROPERTY OF THE UNITED STATES GOVERNMENT
Data Gathering Approach Trane’s Trace 700 (Trace) modeling software was used to determine the HVAC requirements for the Coburn Gore LPOE facility. The results of the Trace modeling are provided for sizing the ground source heat pump/geothermal technology to determine feasibility.
The Trace modeling was based on the floor plans provided for the preferred building alternative in the Parsons Feasibility Study completed for the Coburn Gore LPOE in 2018. The preferred building alternative included construction of a new main building, which will occupy all the square footage as required by the POR and won’t disturb the existing historical main building location. This alternative also included renovation of the historic main building and complete relocation of the four residences. The historic main building renovation plans to house relief quarters for the officers and be used for some of the GSA spatial requirements.
For the new construction, the Trace model treated any areas that weren’t living quarters, bathrooms/locker rooms, exercise rooms, or the public area, as general office space. Since the exact occupancies could not be determined from the feasibility study, the areas treated as general office space had an occupant density of 143 square feet per person with a 250 Btu/h sensible heat load and 200 Btu/h latent heat load per person. The office spaces also accounted for a 0.5 watts per square foot load for standard office equipment. The outside air ventilation requirements for the rooms treated as general office space were calculated with values from ASHRAE 62.1 2016 being 5 cfm per person and
0.06 cfm per square foot. The outside air ventilation requirements for the living bathrooms/locker rooms, exercise rooms, and the public area were also determined from what is required of ASHRAE 62.1 2016 for the intended use of those spaces.
For the renovation of the existing historic building, most of the space was used for officer living quarters.
The outside air ventilation requirement for these spaces was 5 cfm per person and 0.06 cfm per square foot. Again, since there was no way to determine at this stage of the project what the occupancy requirements were for these spaces, it was estimated that there would be one officer per living quarter.
The four residences that are to be relocated had four room types being kitchen space, living space, bedrooms, and bathrooms. These room type outside air ventilation rates were pulled from ASHRAE 62.1 2016 and the occupancies were estimated. It was estimated that only one person would occupy the bedrooms, but there may be 3 occupying the kitchen, dining, and living spaces at one time.
The entirety of the new addition and existing building renovation were given a 0.3 air changes per hour infiltration rate for new construction, which was accounted for in the total heating and cooling loads.
The four residences were given a 0.6 air changes per hour infiltration rate, as the construction of the building is old and most likely not as tight as the other main building.
285.082.002 – Needs Assessment Report September 6, 2024
Geothermal Feasibility Report
PROPERTY OF THE UNITED STATES GOVERNMENT
FOR OFFICIAL USE ONLY
For construction of the new addition, renovation of the existing LPOE building, and the four residences, the slab, wall, and roof U-factors were taken from the 2015 International Energy Conservation Code (IECC) for new construction. The U-factors for the existing building renovation and the four residences were assumed the same in the model as the new building since an update to the wall, roof, and insulation types would most likely be considered to meet current standards if the buildings are going to receive geothermal technology.
The Trace model's total heating load for the new main building was 306.4 MBH and total cooling load was 19.4 tons. For a 13,000 square foot building, the heating load averaged to 23.6 Btus per hour per square foot and the cooling load averaged to 17.9 Btus per hour per square foot.
The Trace model's total heating load for the renovation of the existing main historical building was 204,000 MBH and total cooling load was 11.1 tons. For a 6,500 square foot building, the heating load averaged to 31.4 Btus per hour per square foot and the cooling load averaged to 20.5 Btus per hour per square foot.
The Trace model's total heating load for the 1932 residences was 30 MBH and total cooling load was 1.5 tons. For a 902 square foot building, the heating load averaged to 33.3 Btus per hour per square foot and the cooling load averaged to 20 Btus per hour per square foot.
The Trace model's total heating load for the 1967 residences was 35 MBH and total cooling load was
1.75 tons. For a 1002 square foot building, the heating load averaged to 35 Btus per hour per square foot and the cooling load averaged to 21 Btus per hour per square foot.
These heating and cooling rates fall within expected norms of the building design.
Permits/Regulatory If the geothermal project were to disturb one acre or more of land, stormwater permitting would be required by the Maine Department of Environmental Protection (DEP). The site disturbance of the geothermal system is estimated to be less than 15,000 sf based on the most boreholes and up to 400 sf per bore.
The State of Maine regulates geothermal bores through the ME Dept of Environmental Protection (MEDEP) Underground Injection Control (UIC) program. The geothermal system must be registered via the following forms prior to operating the system.
● Class V Underground Injection Control (UIC) Well Registration
● Supplemental Geothermal Well Information Form
The well drilling contractor must be licensed by the Maine Well Drillers Commission, and they must meet standards found in 144 CMR 232 Well Drillers and Pump Installers Rules.
285.082.002 – Needs Assessment Report September 6, 2024
Geothermal Feasibility Report
PROPERTY OF THE UNITED STATES GOVERNMENT
FOR OFFICIAL USE ONLY
The Parsons Feasibility Study completed for the Coburn Gore LPOE in 2018 considered wetlands mapped by the United States Fish and Wildlife Service (USFWS) National Wetland Inventory (NWI). Per USFWS NWI mapping, there are no wetlands on the LPOE property. However, a freshwater pond and wetlands are mapped close to the expanded LPOE Preferred Alternative site. It is possible that wetlands may exist within the expanded project area. A wetland delineation of the expanded project area is recommended prior to geothermal design, to determine the exact extent of wetlands or waterways in the project area.
Depending on the wetland location and type in relation to the project, a Maine DEP Permit By Rule may be required to satisfy the Natural Resources Protection Act.
Environmental Impacts Maine DEP erosion and sedimentation control best management practices should be implemented during construction. Environmental impacts from sedimentation for the geothermal project are expected to be minimal.
285.082.002 – Needs Assessment Report September 6, 2024
Geothermal Feasibility Report
PROPERTY OF THE UNITED STATES GOVERNMENT
Appendix A Main Building Preliminary Geothermal Sizing
Coburn LPOE Main Building Renovation
LoopLink PRO Design Report
Timothy Roos v.1.2.2
PRELIMINARY
ENTERING WATER TEMPERATURES
The Entering Water Temperatures defined for all of the equipment operating in this Zone Group are as follows.
EWTmin 32 °F EWTmax 80 °F
ZONE GROUP DESIGN DAY
The Zone Group Design Day is the aggregated load including all consituent zones and hot water elements in the zone group. The Zone Group Design Day is the loading profile for which the ground loop is sized.
Cooling (kBtuh) Heating (kBtuh)
8:00AM-12:00PM 80.0 204.0
12:00PM-4:00PM 133.2 122.4
4:00PM-8:00PM 106.6 163.2
8:00PM-8:00AM 66.6 163.2
SPACE SENSIBLE HEAT FACTOR
The zone group space sensible heat factor is the weighted average space sensible heat factor for all zones in the zone group.
Space Sensible Heat Factor (SHF) 0.75
ZONE GROUP CAPACITY
Zone Group Capacity is the aggregated equipment performance defined across all load elements in the Zone Group. These values represent the performance and efficiency of the entire system connected to the loopfield.
Cooling Heating
Total Capacity (kBtuh) 255.6 206.5 Sensible Capacity (kBtuh) 173.1 ---
Percent Total Sizing 191.9 101.2 Percent Sensible Sizing 173.3 ---
Efficiency (EER/COP) 20.3 4.2 Demand (kW) 6.5 14.2
PRELIMINARY ENERGY SUMMARY
ANNUAL ENERGY REQUIREMENTS
The following table describes the annual energy requirements of the Zone Group organized by use.
Cooling Heating
Space Conditioning (kBtu) 62,216 202,138 Hot Water Generation (kBtu) --- 0
Total (kBtu) 62,216 202,138
ENERGY SOURCES AND SINKS
The following table describes how the annual energy requirements of the Zone Group are distirbuted across system sources and sinks.
Cooling Heating
Ground Energy (kBtu) 62,216 202,138
Net Ground Energy (kBtu) -139,922
PRELIMINARY ACTIVE GHEX
COBURN - MAIN RENO 2X5
Active GHEX Type Vertically Bored
GEOMETRY
Rows 2 Bores Per Row 5 Number of Bores 10
Average C-C Spacing 20.00 ft
Length Per Bore The required active length for each bore are calculated as follows. The design length is always the longest of the four.
Cooling Heating
Y1 LENGTH/BORE (ft) 195 453 Y25 LENGTH/BORE (ft) 182 496
DESIGN LENGTH/BORE (ft) 496
Length Total The required active total bore lengths are calculated as follows. The design length is always the longest of the four.
Cooling Heating
Y1 TOTAL LENGTH (ft) 1,949 4,528 Y25 TOTAL LENGTH (ft) 1,820 4,958
TOTAL DESIGN LENGTH (ft) 4,958
FORMATION PROPERTIES
Deep Earth Temperature 48.0 °F
Thermal Conductivity 1.35 Btu/hr ft °F Thermal Diffusivity 0.72 Btu/hr ft °F
U-BEND CONFIGURATION
The U-Bend Configuration defines the number and position of u-bends within the bore.
U-Bend Configuration Single U-Bend Typical (B/C)
BOREHOLE DEFINITION
Bore Diameter 6.00 in
Design Path Piping The design path piping describes the defined type and size of pipe used within the active section of the ground heat exchanger design.
Material HDPE 4710 Dimension Ratio 11 Nominal Diameter 1.00 in
Thermal Grout Conductivity The installed bore is assumed to have an annulus filled from bottom to top with a grouting material with the following thermal conductivity.
Thermal Grout Conductivity 1.20 Btu/hr ft °F
TEMPERATURE PENALTIES
Temperature penalty describes the change in the deep earth temperature immediately surrounding the installed loopfield after extended periods of system operation.
Y1 Penalty -0.17 °F Y25 Penalty -1.24 °F
CIRCULATING FLUID
Antifreeze Type Propylene Glycol Antifreeze Concentration 25 %
Freezing Temperature 15.1 °F
OPERATING TEMPERATURES
EWTmax 80.0 °F EWTmin 32.0 °F
LWTmax 89.3 °F LWTmin 25.9 °F
LOOPFIELD DESIGN FLOW
Preliminary assumes flow is based on Peak Block (Unitary). Which means, flow is a function of the block flow per ton and the aggregated peak block load for the entire zone group. The interior building loop is directly coupled to the exterior GHEX piping where the inside and outside flow rates must be the same.
Block Flow Per Ton 3 gpm
Total Loopfield Flow (gpm) 33.3 51.0
Flow Per Path (gpm) 3.3 5.1 Velocity Per Path (ft/s) 1.2 1.8
Reynold's Number 5,485 2,712
Head Loss /100ft (ft) 0.88 2.24
A head loss table for a Step-Down Step-Up Reverse-Return (SDSU-RR) header is provided in the appendix.
Preliminary Appendix A: Equipment Schedules
PRELIMINARY EQUIPMENT SCHEDULE
WATER-TO-AIR EQUIPMENT
Cooling Heating
Zone Manufacturer Model Tons (nom) QTY
Head Loss (ft
H₂O)
Unit Flow
(gpm)
EATdb (°F)
EATwb (°F)
Air Flow (cfm)
Unit Flow
(gpm)
EATdb (°F)
Air Flow (cfm)
Coburn Gore, Main
Reno - Final for
Feasibility
Trane DXH060
(ECM) 5.00 4 8.8 15.0 80.0 67.0 1,700.0 15.0 70.0 1,700.0
Appendix B: Head Loss Tables
SDSU-RR HEADER (DESIGN FLOW)
The table below describes the exterior head loss in a single headered group during worst case (highest flow) system operation. Interior head loss and pressure drop across attached equipment is not included.
Pipe Run DR Nominal Size (in)
Distance (ft)
Design Flow (gpm)
Design Head Loss/100
(ft)
Design Head Loss (ft)
Mechanical - Bore 1 11.0 3.00 80.0 25.5 0.4 0.3 Bore 1 - Bore 2 11.0 3.00 20.0 20.4 0.3 0.1 Bore 2 - Bore 3 11.0 2.00 20.0 15.3 1.0 0.2 Bore 3 - Bore 4 11.0 1.50 20.0 10.2 1.5 0.3 Bore 4 - Bore 5 11.0 1.00 20.0 5.1 2.2 0.4
Flowpath (HDPE 4710) 11.0 1.00 991.6 5.1 2.2 22.2 Return To Mechanical 11.0 3.00 160.0 25.5 0.4 0.6
Total 24.1
SDSU-RR HEADER (FLUSHING FLOW)
The table below describe the head loss of the system during flushing at the specified 2.0ft/s flushing flow velocity. The flushing flow rate is based on attaing flushing velocity through the flowpath. It has been calculated that using the flushing flow the specified design will not achieve flushing velocity in all sections. An adjusted flushing table has been provided on the following page and is recommended.
Pipe Run DR Nominal Size (in)
Distance (ft)
Flushing Flow (gpm)
Flushing Velocity
(ft/s)
Flushing Head
Loss/100 (ft)
Flushing Head Loss
(ft)
Mechanical - Bore 1 11.0 3.00 80.0 28.3 1.4 0.3 0.3 Bore 1 - Bore 2 11.0 3.00 20.0 22.7 1.1 0.2 0.0 Bore 2 - Bore 3 11.0 2.00 20.0 17.0 1.8 0.8 0.2 Bore 3 - Bore 4 11.0 1.50 20.0 11.3 1.9 1.2 0.2 Bore 4 - Bore 5 11.0 1.00 20.0 5.7 2.0 2.0 0.4
Flowpath (HDPE 4710) 11.0 1.00 991.6 5.7 2.0 2.0 20.2 Return To Mechanical 11.0 3.00 160.0 28.3 1.4 0.3 0.5
Total 21.8
SDSU-RR HEADER (ADJUSTED FLUSHING FLOW)
The table below describes the head loss of the system during flushing at the specified 2.0ft/s flushing flow velocity. However, the flow rate is adjusted to ensure flushing velocity occurs in all sections.
Pipe Run DR Nominal Size (in)
Distance (ft)
Flushing Flow (gpm)
Flushing Velocity
(ft/s)
Flushing Head
Loss/100 (ft)
Flushing Head Loss
(ft)
Mechanical - Bore 1 11.0 3.00 80.0 50.2 2.5 0.9 0.7 Bore 1 - Bore 2 11.0 3.00 20.0 40.1 2.0 0.6 0.1 Bore 2 - Bore 3 11.0 2.00 20.0 30.1 3.3 2.3 0.5 Bore 3 - Bore 4 11.0 1.50 20.0 20.1 3.4 3.2 0.6 Bore 4 - Bore 5 11.0 1.00 20.0 10.0 3.5 5.5 1.1
Flowpath (HDPE 4710) 11.0 1.00 991.6 10.0 3.5 5.5 54.7 Return To Mechanical 11.0 3.00 160.0 50.2 2.5 0.9 1.4
Total 59.1
285.082.002 – Needs Assessment Report September 6, 2024
Geothermal Feasibility Report
PROPERTY OF THE UNITED STATES GOVERNMENT
Appendix B New Main Building Preliminary Geothermal Sizing
New Main Building
LoopLink PRO Design Report
The Entering Water Temperatures defined for all of the equipment operating in this Zone Group are as follows.
EWTmin 32 °F EWTmax 80 °F
ZONE GROUP DESIGN DAY
The Zone Group Design Day is the aggregated load including all consituent zones and hot water elements in the zone group. The Zone Group Design Day is the loading profile for which the ground loop is sized.
Cooling (kBtuh) Heating (kBtuh)
8:00AM-12:00PM 140.0 306.4
12:00PM-4:00PM 323.8 184.0
4:00PM-8:00PM 186.2 245.0
8:00PM-8:00AM 116.4 245.0
SPACE SENSIBLE HEAT FACTOR
The zone group space sensible heat factor is the weighted average space sensible heat factor for all zones in the zone group.
Space Sensible Heat Factor (SHF) 0.75
ZONE GROUP CAPACITY
Zone Group Capacity is the aggregated equipment performance defined across all load elements in the Zone Group. These values represent the performance and efficiency of the entire system connected to the loopfield.
Cooling Heating
Total Capacity (kBtuh) 383.4 309.8 Sensible Capacity (kBtuh) 259.7 ---
Percent Total Sizing 118.4 101.1 Percent Sensible Sizing 106.9 ---
Efficiency (EER/COP) 20.3 4.2 Demand (kW) 15.9 21.4
The following table describes the annual energy requirements of the Zone Group organized by use.
Cooling Heating
Space Conditioning (kBtu) 151,242 303,603 Hot Water Generation (kBtu) --- 0
Total (kBtu) 151,242 303,603
ENERGY SOURCES AND SINKS
The following table describes how the annual energy requirements of the Zone Group are distirbuted
Ground Energy (kBtu) 151,242 303,603
Net Ground Energy (kBtu) -152,361
COBURN - NEW MAIN 3X5
Active GHEX Type Vertically Bored
GEOMETRY
Rows 3 Bores Per Row 5 Number of Bores 15
Average C-C Spacing 20.00 ft
Length Per Bore The required active length for each bore are calculated as follows. The design length is always the longest of the four.
Cooling Heating
Y1 LENGTH/BORE (ft) 291 451 Y25 LENGTH/BORE (ft) 278 488
DESIGN LENGTH/BORE (ft) 488
Length Total The required active total bore lengths are calculated as follows. The design length is always the longest of the four.
Cooling Heating
Y1 TOTAL LENGTH (ft) 4,372 6,765 Y25 TOTAL LENGTH (ft) 4,173 7,327
TOTAL DESIGN LENGTH (ft) 7,327
FORMATION PROPERTIES
U-Bend Configuration Single U-Bend Typical (B/C)
BOREHOLE DEFINITION
Bore Diameter 6.00 in
Design Path Piping The design path piping describes the defined type and size of pipe used within the active section of the ground heat exchanger design.
Material HDPE 4710 Dimension Ratio 11 Nominal Diameter 1.00 in
Thermal Grout Conductivity The installed bore is assumed to have an annulus filled from bottom to top with a grouting material with the following thermal conductivity.
Thermal Grout Conductivity 1.20 Btu/hr ft °F
TEMPERATURE PENALTIES
Temperature penalty describes the change in the deep earth temperature immediately surrounding the installed loopfield after extended periods of system operation.
Y1 Penalty -0.16 °F Y25 Penalty -1.19 °F
CIRCULATING FLUID
Antifreeze Type Propylene Glycol Antifreeze Concentration 25 %
Freezing Temperature 15.1 °F
OPERATING TEMPERATURES
block flow per ton and the aggregated peak block load for the entire zone group. The interior building loop is directly coupled to the exterior GHEX piping where the inside and outside flow rates must be the same.
Block Flow Per Ton 3 gpm
Total Loopfield Flow (gpm) 81.0 76.6
Flow Per Path (gpm) 5.4 5.1 Velocity Per Path (ft/s) 1.9 1.8
Reynold's Number 8,888 2,716
Head Loss /100ft (ft) 2.01 2.25
Cooling Heating
Zone Manufacturer Model Tons (nom) QTY
Head Loss (ft
H₂O)
Unit Flow
(gpm)
EATdb (°F)
EATwb (°F)
Air Flow (cfm)
Unit Flow
(gpm)
EATdb (°F)
Air Flow (cfm)
Coburn Gore, New
Main - Final for
Feasibility
Trane DXH060
(ECM) 5.00 6 8.8 15.0 80.0 67.0 1,700.0 15.0 70.0 1,700.0
The table below describes the exterior head loss in a single headered group during worst case (highest flow) system operation. Interior head loss and pressure drop across attached equipment is not included.
Pipe Run DR Nominal Size (in)
Distance (ft)
Design Flow (gpm)
Design Head Loss/100
(ft)
Design Head Loss (ft)
Mechanical - Bore 1 11.0 3.00 80.0 25.5 0.4 0.3 Bore 1 - Bore 2 11.0 3.00 20.0 20.4 0.3 0.1 Bore 2 - Bore 3 11.0 2.00 20.0 15.3 1.0 0.2 Bore 3 - Bore 4 11.0 1.50 20.0 10.2 1.5 0.3 Bore 4 - Bore 5 11.0 1.00 20.0 5.1 2.2 0.4
Flowpath (HDPE 4710) 11.0 1.00 976.9 5.1 2.2 21.9 Return To Mechanical 11.0 3.00 160.0 25.5 0.4 0.6
Total 23.9
The table below describe the head loss of the system during flushing at the specified 2.0ft/s flushing flow velocity. The flushing flow rate is based on attaing flushing velocity through the flowpath. It has been calculated that using the flushing flow the specified design will not achieve flushing velocity in all sections. An adjusted flushing table has been provided on the following page and is recommended.
Pipe Run DR Nominal Size (in)
Distance (ft)
Flushing Flow (gpm)
Flushing Velocity
(ft/s)
Flushing Head
Loss/100 (ft)
Flushing Head Loss
(ft)
Mechanical - Bore 1 11.0 3.00 80.0 28.3 1.4 0.3 0.3 Bore 1 - Bore 2 11.0 3.00 20.0 22.7 1.1 0.2 0.0 Bore 2 - Bore 3 11.0 2.00 20.0 17.0 1.8 0.8 0.2 Bore 3 - Bore 4 11.0 1.50 20.0 11.3 1.9 1.2 0.2 Bore 4 - Bore 5 11.0 1.00 20.0 5.7 2.0 2.0 0.4
Flowpath (HDPE 4710) 11.0 1.00 976.9 5.7 2.0 2.0 19.9 Return To Mechanical 11.0 3.00 160.0 28.3 1.4 0.3 0.5
Total 21.5
SDSU-RR HEADER (ADJUSTED FLUSHING FLOW)
The table below describes the head loss of the system during flushing at the specified 2.0ft/s flushing flow velocity. However, the flow rate is adjusted to ensure flushing velocity occurs in all sections.
Pipe Run DR Nominal Size (in)
Distance (ft)
Flushing Flow (gpm)
Flushing Velocity
(ft/s)
Flushing Head
Loss/100 (ft)
Flushing Head Loss
(ft)
Mechanical - Bore 1 11.0 3.00 80.0 50.2 2.5 0.9 0.7 Bore 1 - Bore 2 11.0 3.00 20.0 40.1 2.0 0.6 0.1 Bore 2 - Bore 3 11.0 2.00 20.0 30.1 3.3 2.3 0.5 Bore 3 - Bore 4 11.0 1.50 20.0 20.1 3.4 3.2 0.6 Bore 4 - Bore 5 11.0 1.00 20.0 10.0 3.5 5.5 1.1
Flowpath (HDPE 4710) 11.0 1.00 976.9 10.0 3.5 5.5 53.8 Return To Mechanical 11.0 3.00 160.0 50.2 2.5 0.9 1.4
Total 58.3
285.082.002 – Needs Assessment Report September 6, 2024
Geothermal Feasibility Report
PROPERTY OF THE UNITED STATES GOVERNMENT
Appendix C 1932 Residence Preliminary Geothermal Sizing
1932 Residences
LoopLink PRO Design Report
The Entering Water Temperatures defined for all of the equipment operating in this Zone Group are as follows.
EWTmin 32 °F EWTmax 80 °F
ZONE GROUP DESIGN DAY
The Zone Group Design Day is the aggregated load including all consituent zones and hot water elements in the zone group. The Zone Group Design Day is the loading profile for which the ground loop is sized.
Cooling (kBtuh) Heating (kBtuh)
8:00AM-12:00PM 10.8 30.0
12:00PM-4:00PM 18.0 18.0
4:00PM-8:00PM 14.4 24.0
8:00PM-8:00AM 9.0 24.0
SPACE SENSIBLE HEAT FACTOR
The zone group space sensible heat factor is the weighted average space sensible heat factor for all zones in the zone group.
Space Sensible Heat Factor (SHF) 0.75
ZONE GROUP CAPACITY
Zone Group Capacity is the aggregated equipment performance defined across all load elements in the Zone Group. These values represent the performance and efficiency of the entire system connected to the loopfield.
Cooling Heating
Total Capacity (kBtuh) 40.3 31.0 Sensible Capacity (kBtuh) 28.5 ---
Percent Total Sizing 223.8 103.4 Percent Sensible Sizing 211.1 ---
Efficiency (EER/COP) 20.5 4.3 Demand (kW) 0.9 2.0
The following table describes the annual energy requirements of the Zone Group organized by use.
Cooling Heating
Space Conditioning (kBtu) 8,399 29,913 Hot Water Generation (kBtu) --- 0
Total (kBtu) 8,399 29,913
ENERGY SOURCES AND SINKS
The following table describes how the annual energy requirements of the Zone Group are distirbuted
Ground Energy (kBtu) 8,399 29,913
Net Ground Energy (kBtu) -21,514
COBURN - 1932 & 1967 RES
Active GHEX Type Vertically Bored
GEOMETRY
Rows 1 Bores Per Row 2 Number of Bores 2
Average C-C Spacing 20.00 ft
Length Per Bore The required active length for each bore are calculated as follows. The design length is always the longest of the four.
Cooling Heating
Y1 LENGTH/BORE (ft) 133 424 Y25 LENGTH/BORE (ft) 127 440
DESIGN LENGTH/BORE (ft) 440
Length Total The required active total bore lengths are calculated as follows. The design length is always the longest of the four.
Cooling Heating
Y1 TOTAL LENGTH (ft) 267 847 Y25 TOTAL LENGTH (ft) 253 880
TOTAL DESIGN LENGTH (ft) 880
FORMATION PROPERTIES
U-Bend Configuration Single U-Bend Typical (B/C)
BOREHOLE DEFINITION
Bore Diameter 6.00 in
Design Path Piping The design path piping describes the defined type and size of pipe used within the active section of the ground heat exchanger design.
Material HDPE 4710 Dimension Ratio 11 Nominal Diameter 1.00 in
Thermal Grout Conductivity The installed bore is assumed to have an annulus filled from bottom to top with a grouting material with the following thermal conductivity.
Thermal Grout Conductivity 1.20 Btu/hr ft °F
TEMPERATURE PENALTIES
Temperature penalty describes the change in the deep earth temperature immediately surrounding the installed loopfield after extended periods of system operation.
Y1 Penalty -0.03 °F Y25 Penalty -0.26 °F
CIRCULATING FLUID
Antifreeze Type Propylene Glycol Antifreeze Concentration 25 %
Freezing Temperature 15.1 °F
OPERATING TEMPERATURES
block flow per ton and the aggregated peak block load for the entire zone group. The interior building loop is directly coupled to the exterior GHEX piping where the inside and outside flow rates must be the same.
Block Flow Per Ton 3 gpm
Total Loopfield Flow (gpm) 4.5 7.5
Flow Per Path (gpm) 2.2 3.8 Velocity Per Path (ft/s) 0.8 1.3
Reynold's Number 3,705 1,993
Head Loss /100ft (ft) 0.45 0.98
Cooling Heating
Zone Manufacturer Model Tons (nom) QTY
Head Loss (ft
H₂O)
Unit Flow
(gpm)
EATdb (°F)
EATwb (°F)
Air Flow (cfm)
Unit Flow
(gpm)
EATdb (°F)
Air Flow (cfm)
Coburn Gore, 1932 Res - Final for Feasibility
Trane DXV036
(ECM) 3.00 1 10.5 9.0 80.0 67.0 1,140.0 9.0 70.0 1,140.0
The table below describes the exterior head loss in a single headered group during worst case (highest flow) system operation. Interior head loss and pressure drop across attached equipment is not included.
Pipe Run DR Nominal Size (in)
Distance (ft)
Design Flow (gpm)
Design Head Loss/100
(ft)
Design Head Loss (ft)
Mechanical - Bore 1 11.0 1.00 80.0 3.8 1.0 0.8 Flowpath (HDPE 4710) 11.0 1.00 880.2 3.8 1.0 8.6 Return To Mechanical 11.0 1.00 80.0 3.8 1.0 0.8
Total 10.1
The table below describe the head loss of the system during flushing at the specified 2.0ft/s flushing flow velocity.
Pipe Run DR Nominal Size (in)
Distance (ft)
Flushing Flow (gpm)
Flushing Velocity
(ft/s)
Flushing Head
Loss/100 (ft)
Flushing Head Loss
(ft)
Mechanical - Bore 1 11.0 1.00 80.0 5.7 2.0 2.0 1.6 Flowpath (HDPE 4710) 11.0 1.00 880.2 5.7 2.0 2.0 17.9 Return To Mechanical 11.0 1.00 80.0 5.7 2.0 2.0 1.6
Total 21.2
285.082.002 – Needs Assessment Report September 6, 2024
Geothermal Feasibility Report
PROPERTY OF THE UNITED STATES GOVERNMENT
Appendix D 1967 Residence Preliminary Geothermal Sizing
1967 Residences
LoopLink PRO Design Report
The Entering Water Temperatures defined for all of the equipment operating in this Zone Group are as follows.
EWTmin 32 °F EWTmax 80 °F
ZONE GROUP DESIGN DAY
The Zone Group Design Day is the aggregated load including all consituent zones and hot water elements in the zone group. The Zone Group Design Day is the loading profile for which the ground loop is sized.
Cooling (kBtuh) Heating (kBtuh)
8:00AM-12:00PM 12.6 35.0
12:00PM-4:00PM 21.0 21.0
4:00PM-8:00PM 16.8 28.0
8:00PM-8:00AM 10.5 28.0
SPACE SENSIBLE HEAT FACTOR
The zone group space sensible heat factor is the weighted average space sensible heat factor for all zones in the zone group.
Space Sensible Heat Factor (SHF) 0.75
ZONE GROUP CAPACITY
Zone Group Capacity is the aggregated equipment performance defined across all load elements in the Zone Group. These values represent the performance and efficiency of the entire system connected to the loopfield.
Cooling Heating
Total Capacity (kBtuh) 52.1 40.2 Sensible Capacity (kBtuh) 36.6 ---
Percent Total Sizing 248.2 114.8 Percent Sensible Sizing 232.1 ---
Efficiency (EER/COP) 20.9 4.3 Demand (kW) 1.0 2.4
The following table describes the annual energy requirements of the Zone Group organized by use.
Cooling Heating
Space Conditioning (kBtu) 9,770 34,980 Hot Water Generation (kBtu) --- 0
Total (kBtu) 9,770 34,980
ENERGY SOURCES AND SINKS
The following table describes how the annual energy requirements of the Zone Group are distirbuted
Ground Energy (kBtu) 9,770 34,980
Net Ground Energy (kBtu) -25,209
COBURN - 1932 & 1967 RES
Active GHEX Type Vertically Bored
GEOMETRY
Rows 1 Bores Per Row 2 Number of Bores 2
Average C-C Spacing 20.00 ft
Length Per Bore The required active length for each bore are calculated as follows. The design length is always the longest of the four.
Cooling Heating
Y1 LENGTH/BORE (ft) 154 461 Y25 LENGTH/BORE (ft) 146 481
DESIGN LENGTH/BORE (ft) 481
Length Total The required active total bore lengths are calculated as follows. The design length is always the longest of the four.
Cooling Heating
Y1 TOTAL LENGTH (ft) 308 922 Y25 TOTAL LENGTH (ft) 293 961
TOTAL DESIGN LENGTH (ft) 961
FORMATION PROPERTIES
U-Bend Configuration Single U-Bend Typical (B/C)
BOREHOLE DEFINITION
Bore Diameter 6.00 in
Design Path Piping The design path piping describes the defined type and size of pipe used within the active section of the ground heat exchanger design.
Material HDPE 4710 Dimension Ratio 11 Nominal Diameter 1.00 in
Thermal Grout Conductivity The installed bore is assumed to have an annulus filled from bottom to top with a grouting material with the following thermal conductivity.
Thermal Grout Conductivity 1.20 Btu/hr ft °F
TEMPERATURE PENALTIES
Temperature penalty describes the change in the deep earth temperature immediately surrounding the installed loopfield after extended periods of system operation.
Y1 Penalty -0.04 °F Y25 Penalty -0.27 °F
CIRCULATING FLUID
Antifreeze Type Propylene Glycol Antifreeze Concentration 25 %
Freezing Temperature 15.1 °F
OPERATING TEMPERATURES
LWTmax 89.3 °F LWTmin 25.8 °F block flow per ton and the aggregated peak block load for the entire zone group. The interior building loop is directly coupled to the exterior GHEX piping where the inside and outside flow rates must be the same.
Block Flow Per Ton 3 gpm
Total Loopfield Flow (gpm) 5.2 8.8
Flow Per Path (gpm) 2.6 4.4 Velocity Per Path (ft/s) 0.9 1.5
Reynold's Number 4,322 2,325
Head Loss /100ft (ft) 0.59 1.29
Cooling Heating
Zone Manufacturer Model Tons (nom) QTY
Head Loss (ft
H₂O)
Unit Flow
(gpm)
EATdb (°F)
EATwb (°F)
Air Flow (cfm)
Unit Flow
(gpm)
EATdb (°F)
Air Flow (cfm)
Coburn Gore, 1967 Res - Final for Feasibility
Trane DXV048
(ECM) 4.00 1 13.1 12.0 80.0 67.0 1,520.0 12.0 70.0 1,520.0
The table below describes the exterior head loss in a single headered group during worst case (highest flow) system operation. Interior head loss and pressure drop across attached equipment is not included.
Pipe Run DR Nominal Size (in)
Distance (ft)
Design Flow (gpm)
Design Head Loss/100
(ft)
Design Head Loss (ft)
Mechanical - Bore 1 11.0 1.00 80.0 4.4 1.3 1.0 Flowpath (HDPE 4710) 11.0 1.00 961.1 4.4 1.3 12.4 Return To Mechanical 11.0 1.00 80.0 4.4 1.3 1.0
Total 14.5
The table below describe the head loss of the system during flushing at the specified 2.0ft/s flushing flow velocity.
Pipe Run DR Nominal Size (in)
Distance (ft)
Flushing Flow (gpm)
Flushing Velocity
(ft/s)
Flushing Head
Loss/100 (ft)
Flushing Head Loss
(ft)
Mechanical - Bore 1 11.0 1.00 80.0 5.7 2.0 2.0 1.6 Flowpath (HDPE 4710) 11.0 1.00 961.1 5.7 2.0 2.0 19.6 Return To Mechanical 11.0 1.00 80.0 5.7 2.0 2.0 1.6
Total 22.8
285.082.002 – Needs Assessment Report September 6, 2024
Geothermal Feasibility Report
PROPERTY OF THE UNITED STATES GOVERNMENT
Appendix E Ground Source Heat Exchange Evaluation
Report CG-GTB-1
Colby Company Engineering, LLC| 08.26.2024 | 10838.012-003
August 26, 2024
Mr. Ben Townsend, P.E., Vice President Colby Co. Engineering 47A York Street Portland, Maine 04101
Re: Ground Source Heat Exchange Evaluation Report | Land Port of Entry Facility |
Coburn Gore, Maine | CG-GTB-1
Dear Mr. Townsend:
Haley Ward, Inc. (Haley Ward) has prepared this report to provide you with geological and geothermal information for use in assessing a ground source heat exchange (GHEX) system at the existing Coburn Gore United States Land Port of Entry Facility (LPOE) located at 6085 in Coburn Gore, Maine (the Site). Note that the geothermal test bore/well (CG- GTB-1) is the original well located north of The Arnold Trail. The GHEX report associated with the additional well (CG-GTB-2), located south of The Arnold Trail, will submitted separately.
This evaluation is based in part on our documentation of the GHEX test bore drilling and geothermal loop and grout observations, as well as our thermal response testing completed at the Site.
If you have any questions regarding this report, or if you require additional services, please feel free to contact us at (207) 989-4824.
Sincerely, Haley Ward, Inc.
Jeff W. McElroy Jacalyn A. Gorczynski, L.G.
Project Geologist Sr. Project Geologist/Project Manager/ Vice President
JWM/JAG/lmb Enc.
GROUND SOURCE HEAT
EXCHANGE EVALUATION
CG-GTB-1 (Original Well)
LPOE Coburn Gore 6085 The Arnold Trail Coburn Gore, Maine
Prepared for:
Colby Company Engineering, LLC 47A York Street | Portland, ME 04101
AUGUST 26, 2024
JN: 10838.012-003
Report Prepared By:
One Merchants Plaza, Suite 701 | Bangor, Maine 04401
JN: 10838.012-003 I Colby Company Engineering, LLC GHEX Evaluation: CG-GTB-1 LPOE Coburn Gore, Maine
TABLE OF CONTENTS
SECTION PAGE
SECTION 1 | INTRODUCTION
1.1 Purpose
1.2 Limiting Conditions and Methodology
SECTION 2 | SCOPE OF WORK
SECTION 3 | SITE SETTING AND PUBLISHED INFORMATION
3.1 Topographic Setting
3.2 Existing Site Conditions
3.3 Published Geologic Information
3.3.1 Bedrock Mapping
3.3.2 Surficial Mapping
3.3.3 Aquifer Mapping
3.3.4 Water Well Database
SECTION 4 | EXPLORATION AND TESTING
4.1 Geothermal Test Boring
4.2 Thermal Conductivity Testing
SECTION 5 | FINDINGS
5.1 Thermal Conductivity Testing
SECTION 6 | SUMMARY AND RECOMMENDATIONS
APPENDICES
Appendix A Site Location Map Appendix B Geothermal Test Boring Log Appendix C GeoPro, Inc. Thermal Grout Conductivity Analysis Report
Appendix D GLD Thermal Conductivity Report
JN: 10838.012-003 1 Colby Company Engineering, LLC
LPOE Coburn Gore, Maine
GROUND SOURCE HEAT EXHANGE EVALUATION
CG-GTB-1
LPOE COBURN GORE
6085 THE ARNOLD TRAIL, COBURN GORE, MAINE
SECTION 1 | INTRODUCTION
1.1 Purpose
We understand that the purpose of our evaluation is to provide in-situ geothermal information for the ground source heat exchange (GHEX) designer to develop a well field sizing plan to meet the proposed needs for potential construction application at the United States Land Port of Entry (LPOE) Facility located at 6085 The Arnold Trail in Coburn Gore, Maine.
We understand that a closed-loop (the water will exit from and return to the heat pump in a closed piping loop) geothermal system is being planned, or at least is proposed, for the proposed reconstruction project.
1.2 Limiting Conditions and Methodology
There were no limiting conditions or methodology.
SECTION 2 | SCOPE OF WORK
In accordance with our Proposal, we implemented a Scope of Work that included:
• Pre-marking the borehole location at the Site and contacting DigSafe and OKTODIG to notify member and non-member utilities prior to the exploration work at the Site.
• Contracting McLeod Water Wells, LLC (McLeod), a licensed Maine driller, to drill one approximately six-inch diameter 500-foot GHEX test borehole (well) and install a 1¼-inch (inside diameter) HDPE geothermal loop and geothermally enhanced grout tremied into the borehole.
• Escorting Centerline Utility Services to clear the marked borehole location for subsurface utilities at the Site.
• Observing and documenting the drilling, loop installation, and grouting.
• Collecting a sample of the mixed grout being installed in the well for submission to the grout manufacturer for thermal conductivity testing to confirm the designed thermal property requirement of at least 1.0 Btu/hr-ft-oF.
• After waiting a minimum of 120 hours after the GHEX loop installation was completed (grouted and loop pipe filled with fluid), performing a 48-hour thermal response test (a.k.a., thermal conductivity test) in accordance with ASHRAE 2007 HVAC Applications Handbook (pages 32.12-32.13) using a GeoCube Thermal Conductivity Testing Unit (GeoCube) manufactured by Precision Geothermal, LLC, a generator, and materials, as necessary.
JN:…
This is the start of the file's text. The full file is on GovTribe.
File details come from the government source that posted it. Updated .