SIST 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)

A standard on geothermal testing methods is necessary because of the rapidly growing market in Europe of heat exchangers installation. Geothermal heat exchangers are used for heating and cooling and may be used in warmer and cooler areas throughout Europe. The use of geothermal energy leads to a reduction of coal and oil and therefore also of CO2 emissions. The drilling, installation of geothermal heat exchangers and testing for geothermal conductivity has to be determined by a standardised testing procedure.

Geotechnische Erkundung und Untersuchung - Geothermische Versuche - Bestimmung der Wärmeleitfähigkeit von Boden und Fels unter Anwendung von Erdwärmesonden (ISO 17628:2015)

Reconnaissance et essais géotechniques - Essais géothermiques - Détermination de la conductivité thermique de sol et roche dans les sondes géothermiques (ISO 17628:2015)

L'ISO 17628:2015 spécifie les exigences relatives à l'essai de réponse géothermique. Cet essai comprend la détermination in situ de la conductivité thermique dans un sol et une roche saturés et non saturés à l'aide d'une sonde géothermique. Pour cet essai, des liquides caloporteurs ne subissant pas de changements de phase sont utilisés.
La conductivité thermique est un paramètre important utilisé dans la conception des systèmes de stockage et d'échange thermiques.
Un essai de réponse géothermique mesure la réponse en température au forçage thermique d'une sonde géothermique ou l'extraction d'énergie thermique d'un forage. La réponse en température est liée aux paramètres thermiques du sol et du forage tels que la conductivité thermique et la résistance du forage ; elle est donc utilisée pour obtenir des estimations de ces paramètres importants.
L'ISO 17628:2015 s'applique aux sondes géothermiques installées dans des forages verticaux ou inclinés d'une profondeur courante allant jusqu'à 400 m, par exemple, et d'un diamètre allant jusqu'à 200 mm.

Geotehnično preiskovanje in preskušanje - Geotermalno preskušanje - Ugotavljanje toplotne prevodnosti zemlje in skal z uporabo vrtine toplote (ISO 17628:2015)

Standard, ki ureja geotermalne preskusne metode, je potreben zaradi hitro rastočega trga toplotnih izmenjevalnikov v Evropi. Geotermalni toplotni izmenjevalniki se uporabljajo za ogrevanje in hlajenje in se lahko uporabljajo v toplejših in hladnejših območjih v Evropi. Uporaba geotermalne energije zmanjšuje uporabo premoga in nafte ter posledično emisij CO2. Vrtanje, namestitev geotermalnih izmenjevalnikov toplote in preskušanje geotermalne prevodnosti mora biti določeno s standardiziranim preskusnim postopkom.

General Information

• Status: Published
• Public Enquiry End Date: 17-Oct-2013
• Publication Date: 22-Sep-2015
• ICS: 27.190 - Biological sources and alternative sources of energy
• ICS: 93.020 - Earthworks. Excavations. Foundation construction. Underground works
• Technical Committee: KON.007 - Geotechnics
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 06-Aug-2015
• Due Date: 11-Oct-2015
• Completion Date: 23-Sep-2015
• Ref Project: 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)

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN ISO 17628:2015
01-oktober-2015
*HRWHKQLþQRSUHLVNRYDQMHLQSUHVNXãDQMH*HRWHUPDOQRSUHVNXãDQMH
8JRWDYOMDQMHWRSORWQHSUHYRGQRVWL]HPOMHLQVNDO]XSRUDERYUWLQHWRSORWH,62

Geotechnical investigation and testing - Geothermal testing - Determination of thermal
conductivity of soil and rock using a borehole heat exchanger (ISO 17628:2015)
Geotechnische Erkundung und Untersuchung - Geothermische Versuche - Bestimmung
der Wärmeleitfähigkeit von Boden und Fels unter Anwendung von Erdwärmesonden
(ISO 17628:2015)
Reconnaissance et essais géotechniques - Essais géothermiques - Détermination de la
conductivité thermique de sol et roche dans les sondes géothermiques (ISO
17628:2015)
Ta slovenski standard je istoveten z: EN ISO 17628:2015
ICS:
27.190 Biološki viri in drugi Biological sources and
alternativni viri energije alternative sources of energy
93.020 Zemeljska dela. Izkopavanja. Earthworks. Excavations.
Gradnja temeljev. Dela pod Foundation construction.
zemljo Underground works
SIST EN ISO 17628:2015 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 17628:2015

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SIST EN ISO 17628:2015

EUROPEAN STANDARD
EN ISO 17628

NORME EUROPÉENNE

EUROPÄISCHE NORM
July 2015
ICS 93.020; 13.080.20
English Version
Geotechnical investigation and testing - Geothermal testing -
Determination of thermal conductivity of soil and rock using a
borehole heat exchanger (ISO 17628:2015)
Reconnaissance et essais géotechniques - Essais Geotechnische Erkundung und Untersuchung -
géothermiques - Détermination de la conductivité thermique Geothermische Versuche - Bestimmung der
des sols et des roches dans les sondes géothermiques Wärmeleitfähigkeit von Boden und Fels unter Anwendung
(ISO 17628:2015) von Erdwärmesonden (ISO 17628:2015)
This European Standard was approved by CEN on 23 April 2015.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same
status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United
Kingdom.





EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2015 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 17628:2015 E
worldwide for CEN national Members.

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SIST EN ISO 17628:2015
EN ISO 17628:2015 (E)
Contents Page
European foreword .3

2

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SIST EN ISO 17628:2015
EN ISO 17628:2015 (E)
European foreword
This document (EN ISO 17628:2015) has been prepared by Technical Committee CEN/TC 341 “Geotechnical
Investigation and Testing”, the secretariat of which is held by BSI, in collaboration with Technical Committee
ISO/TC 182 "Geotechnics".
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by January 2016, and conflicting national standards shall be withdrawn at
the latest by January 2016.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
Endorsement notice
The text of ISO 17628:2015 has been approved by CEN as EN ISO 17628:2015 without any modification.
3

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SIST EN ISO 17628:2015

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SIST EN ISO 17628:2015
INTERNATIONAL ISO
STANDARD 17628
First edition
2015-07-15
Geotechnical investigation and
testing — Geothermal testing
— Determination of thermal
conductivity of soil and rock using a
borehole heat exchanger
Reconnaissance et essais géotechniques — Essais géothermiques —
Détermination de la conductivité thermique des sols et des roches
dans les sondes géothermiques
Reference number
ISO 17628:2015(E)
©
ISO 2015

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SIST EN ISO 17628:2015
ISO 17628:2015(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2015, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. [phone]
Fax [phone]
[e-mail]
www.iso.org
ii © ISO 2015 – All rights reserved

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SIST EN ISO 17628:2015
ISO 17628:2015(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviations . 3
5 Installation of borehole heat exchangers . 4
5.1 Drilling rigs and ancillary equipment . 4
5.1.1 General. 4
5.1.2 Requirements for the drilling rigs and equipment . 4
5.2 Borehole heat exchangers, filling, and annular space filling materials . 5
5.2.1 Borehole heat exchanger material . 5
5.2.2 Heat transfer fluid of the borehole heat exchanger tubes . 5
5.2.3 Annular space filling material . 5
5.3 General requirements prior to installation . 6
5.3.1 Requirements on the drilling and installation site . 6
5.3.2 Selection of drilling techniques and installation methods . 6
5.3.3 Preliminary information needed before starting drilling and installation . . 6
5.3.4 Environmental requirements . 7
5.3.5 Safety requirements . 7
5.4 Execution. 7
5.4.1 Drilling . 7
5.4.2 Installation of borehole heat exchangers . 8
5.4.3 Annular space filling . 8
5.4.4 Functional testing . 9
5.4.5 Site reinstatement . . .12
6 Geothermal response testing .12
6.1 General .12
6.2 Test equipment .13
6.3 Test procedure .13
6.4 Test results.15
6.5 Evaluation of the test results .15
7 Report .16
7.1 Field report .16
7.1.1 Record of the installation of the heat exchanger tubes .17
7.1.2 Annular space filling record .17
7.1.3 Checking record .18
7.1.4 Record of measured values and test results .18
7.1.5 Record of evaluated test results .18
7.2 Report of the results .18
Annex A (informative) Example of a form for the preliminary information on the intended
installation of heat exchanger .20
Annex B (informative) Field reports .22
Annex C (informative) Example of the graphical presentation of the installed borehole heat
exchanger and the geology along the borehole .27
Bibliography .28
© ISO 2015 – All rights reserved iii

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SIST EN ISO 17628:2015
ISO 17628:2015(E)

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any
patent rights identified during the development of the document will be in the Introduction and/or on
the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information
ISO 17628 was prepared by European Committee for Standardization (CEN) Technical Committee
CEN/TC 341, Geotechnical investigation and testing, in collaboration with ISO Technical Committee
ISO/TC 182, Geotechnics, Subcommittee SC 1, in accordance with the agreement on technical cooperation
between ISO and CEN (Vienna Agreement).
iv © ISO 2015 – All rights reserved

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SIST EN ISO 17628:2015
INTERNATIONAL STANDARD ISO 17628:2015(E)
Geotechnical investigation and testing — Geothermal
testing — Determination of thermal conductivity of soil
and rock using a borehole heat exchanger
1 Scope
This International Standard specifies requirements for the Geothermal Response Test (GRT). This test
comprises the in situ determination of the thermal conductivity in saturated and unsaturated soil and
rock in a heat exchanger installed in a borehole. For this test, liquid heat transfer media not subjected to
phase changes are used.
The thermal conductivity is an important parameter used in the design of thermal storage and thermal
exchange systems.
A Geothermal Response Test measures the temperature response to a thermal energy forcing of a
borehole heat exchanger (BHE) or the extraction of thermal energy from a borehole. The temperature
response is related to the thermal parameters of the ground and borehole filling material, such as
thermal conductivity and borehole resistivity, and is therefore used to obtain estimated or derived
values of these parameters.
This International Standard applies to heat exchangers installed in vertical or inclined boreholes with
length up to e.g. 400 m and with a diameter of up to 200 mm.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 14688-1, Geotechnical investigation and testing — Identification and classification of soil — Part 1:
Identification and description
ISO 14689-1, Geotechnical investigation and testing — Identification and classification of rock — Part 1:
Identification and description
ISO 22475-1, Geotechnical investigation and testing — Sampling methods and groundwater measurements —
Part 1: Technical principles for execution
EN 16228-1, Drilling and foundation equipment - Safety - Part 1: Common requirements
EN 16228-2, Drilling and foundation equipment - Safety - Part 2: Mobile drill rigs for civil and geotechnical
engineering, quarrying and mining
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 22475-1 and the following apply.
3.1
borehole heat exchanger
BHE
one or two U-tubes or one coaxial tube in a borehole through which the exchanger fluid circulates
Note 1 to entry: See Figure 1 and Figure 2.
© ISO 2015 – All rights reserved 1

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s
r
r
s
SIST EN ISO 17628:2015
ISO 17628:2015(E)

s
r1
B
F
E
a) single U-tube
s
r
1
B
F
E
b) double U-tube c) coaxial tube
Key
r borehole radius λ thermal conductivity of the annular space filling
1 F
r inner radius λ thermal conductivity of the inner borehole tube
i w
r outer radius λ thermal conductivity of the outer borehole tube
a s
r inner radius of the outer tube λ thermal conductivity of the ground
o E
r outer radius of the outer tube B tube spacing
s
Figure 1 — Cross-section of examples of borehole heat exchanger tubes
2 © ISO 2015 – All rights reserved
r
0
0
r

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SIST EN ISO 17628:2015
ISO 17628:2015(E)

6
1
2
3
4
5
Key
1 heat exchanger outlet
2 heat exchanger inlet
3 borehole wall
4 annular space filling
5 connection
6 ground level
Figure 2 — Example of a borehole heat exchanger including annular space filling
3.2
geothermal response test
test to obtain the thermal conductivity
4 Symbols and abbreviations
Table 1 — List of symbols and abbreviations
Symbol Designation Unit
2
A total cross sectional area of a conducting surface m
B tube spacing m
H length of the borehole heat exchanger m
k slope
m mass of a substance kg
3
ρc volume related thermal capacity J/m /K
p
Q heat supply W
r borehole radius m
0
r inner radius m
i
© ISO 2015 – All rights reserved 3

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SIST EN ISO 17628:2015
ISO 17628:2015(E)

Table 1 (continued)
Symbol Designation Unit
r outer radius m
a
r inner radius of the outer tube m
o
r outer radius of the outer tube m
s
Re Reynold’s number
R borehole resistance
b
T temperature °C
T undisturbed ground temperature °C
0
T fluid temperature at time t °C
f
t minimum test duration
1
x thickness of the conducting surface separating two different temperatures m
λ thermal conductivity W/m/K
λ thermal conductivity of the ground W/m/K
E
λ effective thermal conductivity W/m/K
eff
λ estimated thermal conductivity W/m/K
est
λ thermal conductivity of the annular space filling W/m/K
F
λ thermal conductivity of the outer borehole tube W/m/K
s
λ thermal conductivity of the inner borehole tube W/m/K
w
5 Installation of borehole heat exchangers
5.1 Drilling rigs and ancillary equipment
5.1.1 General
The drilling equipment selected shall be of the appropriate size and type in order to produce the
required quality.
5.1.2 Requirements for the drilling rigs and equipment
Drilling rigs with appropriate stability, power, and equipment such as drill rods, casing, core barrels,
and bits shall be selected in order that the required depth and stability of the borehole can be achieved.
The drilling rig and equipment shall allow all drilling functions to be adjusted accurately.
When specified, the following drilling parameters should be measured and recorded against depth:
a) penetration rate (m/min);
b) drilled length (m);
c) flushing medium recovery rate (l/min);
d) azimuth and inclination (degree);
e) borehole diameter (mm);
f) casing and casing length (m);
g) flush medium.
4 © ISO 2015 – All rights reserved

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SIST EN ISO 17628:2015
ISO 17628:2015(E)

5.2 Borehole heat exchangers, filling, and annular space filling materials
5.2.1 Borehole heat exchanger material
The material of the borehole heat exchanger tubes and bottom concerning the following shall be selected
related to the purpose and the design:
a) quality;
b) durability;
c) corrosion;
d) thermal resistance;
e) impact resistance;
f) hydraulic resistance;
g) compressive strength;
h) resistance to deformation;
i) safety, related to contamination of the ground and ground water;
j) dimensions (diameter, wall thickness, and distance).
Plastic tubes shall have the quality of at least PE 100 black pipe for non-potable underground use and should
be made of the same material as the borehole heat exchanger which will be installed for the later BHE-array.
Tube spacers shall be attached to U-tubes in order to avoid thermal shortcuts. The minimum spacer
distance shall be at least 2 m.
Beginning at the bottom of the borehole heat exchanger, the tubes shall possess length marks every
meter in numerical order starting at zero and increasing to the end of the tubes to check the installed
length at all times.
5.2.2 Heat transfer fluid of the borehole heat exchanger tubes
The heat transfer fluid of the borehole heat exchanger tubes shall fulfil the requirements of the test
design and the environmental regulations.
Water or de-ionized water should be used because of its good hydrodynamic properties and it does not
endanger the ground and the groundwater, if a leakage of the borehole heat exchanger occurs.
The specific thermal capacity of the heat transfer fluid shall be known.
The use of antifreeze additives shall be justified. If used, the annular space filling has to be adapted to
freezing and thawing conditions in order to avoid cracks.
The design shall take into account the minimum temperature of the heat transfer fluid.
5.2.3 Annular space filling material
The annular space filling material shall provide the thermal transport from the ground to the borehole
heat exchanger and vice versa. It shall seal the borehole to the ground level to prevent contaminants
from entering and aquifers that might have been penetrated. The filling material shall ensure a durable,
physically and chemically stable incorporation of the borehole heat exchanger in the ground. It shall be
suited for all the respective deployment temperatures.
The filling material shall be selected according to expected thermal conductivity of the surrounding
ground and ground water.
© ISO 2015 – All rights reserved 5

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SIST EN ISO 17628:2015
ISO 17628:2015(E)

Thermally improved filling materials with a thermal conductivity of > 2 W/mK should be used.
The material shall be chemically harmless for the environment and health.
5.3 General requirements prior to installation
5.3.1 Requirements on the drilling and installation site
Drilling points shall be marked on the site before drilling commences. Their location and elevation shall
be surveyed correctly and in accordance with site conditions and entered in a site plan on completion
of the installation.
Drilling and installation sites shall be investigated with respect to relevant hazards, underground
utilities, former or current underground mining activities, natural cavities, and unexpected, unexploded
ordnance and, if necessary, appropriate actions have to be taken. Installation locations on contaminated
ground have to be dealt with by special procedures.
The environmental impact of drilling and installation shall be considered. Special principles have to
be applied in
— water supply areas,
— areas with artesian or confined groundwater conditions,
— areas with multiple aquifers, and
— grounds with swellable or collapsible rocks or soils.
The distance to existing buildings should be at least 2 m; the stability may not be jeopardized.
5.3.2 Selection of drilling techniques and installation methods
The techniques and methods for drilling and installation shall be selected according to the purpose of
the borehole heat exchanger in relation to the expected geological and hydrogeological conditions.
If installation in unstable ground is necessary, stable or stabilized boreholes are required using casings
or suitable flushing media.
Sampling techniques, sample transportation, and storage procedures shall be selected according to
ISO 22475-1 on the basis of the required sample quality class.
The knowledge of the geological and hydrogeological conditions is necessary for the interpretation of
the results of the Geothermal response test and for the selection of the annular space filling material.
5.3.3 Preliminary information needed before starting drilling and installation
The following preliminary information shall be available before starting drilling and installation:
a) location of the planned borehole heat exchanger;
b) requirements on numbering of boreholes;
c) identification and planned depths of boreholes based on the outline design;
d) orientation, inclination, and acceptable deviations in boreholes;
e) installation plan of the borehole heat exchanger including the annular space filling;
f) tolerances of borehole depth and installation length;
g) expected geology and hydrogeology;
6 © ISO 2015 – All rights reserved

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SIST EN ISO 17628:2015
ISO 17628:2015(E)

h) space requirements, accessibility of the drilling site, transport routes;
i) environmental and safety risks associated with, e.g. flushing media or additives intended to be used
as well as regulations for their use;
j) possible risks, e.g. underground and overhead services, traffic, unexpected and unexploded
ordnance, contamination;
k) preparation of the disposal of drilling mud and cuttings;
l) supply of auxiliary materials, water and energy;
m) sampling method and sampling category intended;
n) sample handling, storage, and transport intended according to ISO 22475-1;
o) requirements concerning planned measurements in the borehole heat exchanger;
p) required accuracy and uncertainty of measurements;
q) frequency of measurements;
r) in situ tests intended;
s) site reinstatement;
t) environmental care;
u) emergency arrangements;
v) clarification of necessary permissions;
w) name of contact person;
x) planned flow of information.
5.3.4 Environmental requirements
Regarding nuisance and environmental protection, for each particular situation, the respective national
standards, specifications or statutory requirements or respective international standards shall be applied.
5.3.5 Safety requirements
Regarding safety on the site and safety of the working practices, the respective national standards,
specifications or statutory requirements or respective international standards shall be applied.
Drill rigs shall be in accordance with EN 16228-1 and EN 16228-2.
Every borehole shall be fenced or temporarily capped in a safe manner until the installation has been finished.
5.4 Execution
5.4.1 Drilling
The drilling methods have to be selected according to the expected geology and hydrogeology. In the
case th
...