| Thermal Conductivity Test and Analysis |
A thermal conductivity test includes the drilling of a single borehole, as associated pipe and grouting to facilitate the acquisition of data from the rock formation beneath the site in which you wish to install a vertical ground heat-exchanger. The gathered data will provide information regarding the thermal conductivity, thermal diffusivity, and undisturbed temperature of the earth at a depth of 100 meters from the earth’s surface. Thermal conductivity/diffusivity of the ground is essentially the ability of the ground to absorb and/or release energy. This information is necessary in order to accurately design a ground heat-exchanger capable of transferring energy to and from the earth for the purpose of heating and cooling a building.
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| A Thermal Conductivity Test includes: |
- Transport of all necessary drilling, grouting, and testing equipment to the site.
- Drilling of a single borehole of 6” diameter to a depth of 100 meters from the earth’s surface at a suitable location.
- Installation of a 1” high density polyethylene plastic pipe and u-tube assembly manufactured to standard SDR11, fusion welded at all joints, pressure tested, and charged with potable water.
- Provide a permanent environmental seal of the entire borehole using a limestone based grout, sand, and water mixture. The grout mixture shall be pumped from the bottom of the borehole upward to the very top.
- A detailed thermal conductivity testing report.
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| General Thermal Conductivity Drilling and Testing Procedure: |
The table below describes the procedure for a thermal conductivity test and analysis:
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| Steps |
Timeline |
| 1. Equipment Transportation and Set-up |
1 day |
| 2. Drilling, Piping, and Grouting of 100 meter borehole |
3 days |
3. Undisturbed Earth Temperature
In order measure the undisturbed temperature of the earth, the finished geothermal borehole must remain in the earth until it assumes the same temperature as the earth |
5 days |
| 4. Conductivity Test* |
48 hours (continuous) |
| 5. Conductivity Analysis |
2 weeks |
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* If the conductivity test is interrupted during the 48 hour test, the geothermal borehole must be allowed to return to the steady-state conditions of the earth before the test is attempted again. |
