Thermal Needle Probe measurement Thermal Needle Probe measurement
Thermal needle probe measurements are used to measure ground conductivity at shallow depths.
Thermal needle probe measurements are used to measure ground conductivity at shallow depths.
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What is a Needle Probe Measurement?
A needle probe measurement is a testing method used to determine the thermal conductivity of the ground at shallow depths, typically where a horizontal ground loop is being considered for a ground source heat pump system.
This method is especially useful during the early design phase of a system, providing important data to inform the size and layout of horizontal ground collectors.
How It Works:
- The ground is lightly augured (bored) by a technician to create access at specific depths.
- A thermal needle probe, which contains both a heating element and a temperature sensor, is inserted into the soil.
- The probe applies a controlled amount of heat while recording how the temperature changes over time.
- This data is then analysed using thermal equations to calculate the soil’s thermal conductivity.
- Multiple readings may be taken across the site to improve accuracy, and the results are combined to produce a geometric mean thermal conductivity value for the location.
Why It’s Useful:
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Non-invasive and low-cost – ideal for small to mid-scale projects.
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Helps ensure the horizontal ground array is correctly sized and spaced.
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Assists in predicting system efficiency and long-term performance.
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Quicker and simpler than full-scale Thermal Response Testing, especially where boreholes are not planned.
When Is It Used?
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On sites proposing horizontal ground loops for GSHP systems.
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When shallow ground conditions need to be assessed.
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During feasibility studies or preliminary design stages.
Needle probe testing gives designers and installers like Geowarmth a reliable, data-backed understanding of local ground conditions—ensuring efficient, well-sized systems with reduced design risk.
Contact Us
If you’re unsure what’s right for your home or commercial space, provide some details here and we can get in touch to talk to you about your property
Contact Us
If you’re unsure what’s right for your home or commercial space, provide some details here and we can get in touch to talk to you about your property