EN ISO 17628:2015 PDF

Overview

EN ISO 17628:2015 - Geotechnical investigation and testing - Geothermal testing - Determination of thermal conductivity of soil and rock using a borehole heat exchanger (ISO 17628:2015) specifies an in situ test method (Geothermal Response Test, GRT) for determining the thermal conductivity of soils and rock using a borehole heat exchanger (BHE). The standard covers installation and testing of vertical or inclined boreholes (examples given up to about 400 m length and diameters up to ~200 mm) using liquid heat transfer media that do not undergo phase change. EN ISO 17628:2015 is intended to provide reliable ground thermal parameters for the design of geothermal exchange systems and thermal storage.

Key topics and technical requirements

• Geothermal Response Test (GRT): measurement of temperature response to a known thermal forcing or extraction in a BHE to derive ground thermal properties (thermal conductivity, borehole thermal resistance).
• Borehole heat exchanger installation: requirements for drilling rigs, installation methods, BHE materials (U‑tubes or coaxial), annular space filling materials and heat transfer fluids.
• Test equipment and procedure: instrumentation, test execution, data recording, test duration and procedures for obtaining reproducible temperature response data.
• Data evaluation and reporting: methods to evaluate thermal conductivity and borehole resistivity, presentation of measured values and interpreted results.
• Site and safety requirements: pre-installation information, environmental protection, safety standards and site reinstatement following testing.
• Documentation: prescribed field reports, installation records, annular filling records and example forms and graphical presentations (annexes included).

Applications

EN ISO 17628:2015 is used to obtain accurate, site-specific ground thermal parameters critical for:

• Designing ground source heat pump systems and borehole field layouts
• Sizing geothermal heat exchangers and thermal storage systems
• Reducing design uncertainty for heating and cooling installations
• Supporting feasibility studies and energy performance modeling Using standardized geothermal testing methods improves system efficiency and contributes to carbon-emission reduction goals by enabling optimal use of geothermal energy.

Who should use this standard

• Geotechnical and geothermal engineers
• Energy consultants and HVAC designers
• Drilling and ground‑works contractors installing BHEs
• Research laboratories performing in situ thermal testing
• Project owners, building services designers and local authorities assessing geothermal projects

Related standards

Normative references commonly used with EN ISO 17628:2015 include:

• ISO 14688-1 (soil identification and description)
• ISO 14689-1 (rock identification and description)
• ISO 22475-1 (sampling methods and groundwater measurements)
• EN 16228‑1 / EN 16228‑2 (drilling equipment safety)

Keywords: EN ISO 17628:2015, geothermal testing, borehole heat exchanger, thermal conductivity, Geothermal Response Test, ground source heat pump, in situ thermal testing.