SIST-TP CWA 17941:2022

SLOVENSKI STANDARD
SIST CWA 17941:2022
01-december-2022
Smernice za celostni pristop k projektom prenove stavb na podlagi izboljšanih
plitvih geotermalnih tehnologij
Guidelines for an integrated approach of building retrofitting projects based on enhanced
shallow geothermal technologies
Planungs- und Installationsrichtlinien für ein Gebäudesanierungskonzept auf Basis von
EGS (Enhanced Geothermal Systems)
Ta slovenski standard je istoveten z: CWA 17941:2022
ICS:
27.190 Biološki viri in drugi Biological sources and
alternativni viri energije alternative sources of energy
91.140.10 Sistemi centralnega Central heating systems
ogrevanja
SIST CWA 17941:2022 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST CWA 17941:2022

---------------------- Page: 2 ----------------------
SIST CWA 17941:2022


CEN
CWA 17941

WORKSHOP
October 2022

AGREEMENT


ICS 27.190; 91.140.10
English version


Guidelines for an integrated approach of building
retrofitting projects based on enhanced shallow
geothermal technologies
This CEN Workshop Agreement has been drafted and approved by a Workshop of representatives of interested parties, the
constitution of which is indicated in the foreword of this Workshop Agreement.

The formal process followed by the Workshop in the development of this Workshop Agreement has been endorsed by the
National Members of CEN but neither the National Members of CEN nor the CEN-CENELEC Management Centre can be held
accountable for the technical content of this CEN Workshop Agreement or possible conflicts with standards or legislation.

This CEN Workshop Agreement can in no way be held as being an official standard developed by CEN and its Members.

This CEN Workshop Agreement is publicly available as a reference document from the CEN Members National Standard Bodies.

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



EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2022 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members.


Ref. No.:CWA 17941:2022 E

---------------------- Page: 3 ----------------------
SIST CWA 17941:2022
CWA 17941:2022 (E)
Contents Page
Foreword . 3
Introduction . 4
1 Scope . 7
2 Normative references . 7
3 Terms, definitions, and abbreviations . 7
4 Steps for an integrated approach . 8
4.1 Building the integrated project design team . 8
4.1.1 Clients . 9
4.1.2 Designers . 10
4.1.3 Contractors . 11
4.1.4 Managers . 11
4.2 Defining main phases and identifying primary roles in the SGE building retrofitting
project . 12
4.2.1 Project life-cycle phases . 12
4.2.2 Primary roles of actors . 13
4.3 Developing a collaborative workflow schedule . 23

2

---------------------- Page: 4 ----------------------
SIST CWA 17941:2022
CWA 17941:2022 (E)
Foreword
This CEN Workshop Agreement (CWA 17941:2022) has been developed in accordance with the CEN-
CENELEC Guide 29 “CEN/CENELEC Workshop Agreements – A rapid way to standardization” and with
the relevant provisions of CEN/CENELEC Internal Regulations - Part 2. It was approved by a Workshop
of representatives of interested parties on 2022-09-30, the constitution of which was supported by CEN
following the public call for participation made on 2022-02-25. However, this CEN Workshop Agreement
does not necessarily include all relevant stakeholders.
The final text of this CEN Workshop Agreement was provided to CEN for publication on 2022-10-04.
Results incorporated in this CWA received funding from the European Union’s Horizon 2020 research
and innovation programme under grant agreement No 792210.
The following organizations and individuals developed and approved this CEN Workshop Agreement:
• COMSA INSTALACIONES Y SISTEMAS INDUSTRIALES SA (Antonio Galindo Fernandez)
• FAHRENHEIT GMBH (Ursula Wittstadt)
• i.LECO NV (Adriaan Brebels)
• IDP INGENIERIA Y ARQUITECTURA IBERIA SLU (Mikel Borràs / Eduard Loscos)
• IDS GEORADAR SRL (Guido Manacorda)
• NATIONAL UNIVERSITY OF IRELAND GALWAY (Marcus M. Keane / Luis M. Blanes)
• NOBATEK INEF 4 (Romain Lhomer)
• R2M SOLUTION SRL (Marco Calderoni)
• SINDEQ BORRTEKNIK AB (Lasse Aman)
Attention is drawn to the possibility that some elements of this document may be subject to patent rights.
CEN-CENELEC policy on patent rights is described in CEN-CENELEC Guide 8 “Guidelines for
Implementation of the Common IPR Policy on Patent”. CEN shall not be held responsible for identifying
any or all such patent rights.
Although the Workshop parties have made every effort to ensure the reliability and accuracy of technical
and nontechnical descriptions, the Workshop is not able to guarantee, explicitly or implicitly, the
correctness of this document. Anyone who applies this CEN Workshop Agreement shall be aware that
neither the Workshop, nor CEN, can be held liable for damages or losses of any kind whatsoever. The use
of this CEN Workshop Agreement does not relieve users of their responsibility for their own actions, and
they apply this document at their own risk. The CEN Workshop Agreement should not be construed as
legal advice authoritatively endorsed by CEN/CENELEC.
3

---------------------- Page: 5 ----------------------
SIST CWA 17941:2022
CWA 17941:2022 (E)
Introduction
In Europe, the building sector is responsible for 40% of the total energy consumption and represents
about a third of Europe’s CO emissions. Heating and cooling accounts for 50% of annual energy
2
1
consumption in EU, making it the biggest energy end-use sector ahead of both transport and electricity ).
This is a huge socioeconomic and environmental problem, considering that roughly 75% of EU buildings
2)
are not energy efficient , and that approximately 75% of heating and cooling is still generated from fossil
3)
fuels . On this basis, buildings represent a large energy-savings potential, once renovated and upgraded,
if the heating and cooling sector sharply reduces its energy consumption and cuts its use of fossil fuels to
fulfil the EU’s climate and energy goals. However, today the annual renovation rate of the building stock
varies from just 0.4 to 1.2% in the Member States. According to the European Green Deal, this rate will
need to at least double to reach the EU’s energy efficiency and climate objectives.
Given the labour-intensive nature of the construction sector, which is largely dominated by local
businesses, building renovation plays a crucial role in European economic recovery especially following
the COVID-19 pandemic. To kick-start the recovery, the Commission has launched several initiatives to
2)
further support the renovation of EU buildings .
To pursue this dual ambition of energy savings and economic growth, in 2020 the Commission published
a new strategy to boost energy-efficient building retrofitting called "A Renovation Wave for Europe –
Greening our buildings, creating jobs, improving lives". Also, the EU has established a legislative
framework (which includes the Energy Performance of Buildings Directive 2010/31/EU (EPBD) and the
Energy Efficiency Directive 2012/27/EU), providing direction to the future sustainable built
environment by supporting low carbon energy usage in buildings.
In this context, shallow geothermal energy (SGE) is a renewable energy source (RES) with large potential
to facilitate energy savings and GHG emissions reduction in the building sector and therefore help to
achieve all major objectives of the EU’s energy policy. Moreover, the main reference organisations - such
4) 5)
as ECTP and RHC-ETIP - have promoted and roadmapped the cost-effective integration of RES into
building technical systems. The development of effective and affordable enhanced geothermal systems
(EGSs) is crucial to exploit the EU geothermal potential as a major source of energy supply for heating
and cooling purposes, by targeting bottlenecks that hinder the full deployment of geothermal systems as
one of the key concepts in energy efficient building retrofitting.
This CWA is motivated by the main goals of the EU Horizon 2020 GEOFIT innovation project
(funded under grant agreement number 792210). It is meant to provide general management
guidelines for stakeholders involved in a building retrofit project based on SGE technologies.
The type of SGE building retrofit project which is addressed in this CWA focuses on the
technologies described below. However, it is necessary to consider that SGE building retrofitting
does not explicitly require the use of all these specific technologies.

1
) https://ec.europa.eu/energy/topics/energy-efficiency/heating-and-cooling
2
) https://ec.europa.eu/energy/topics/energy-efficiency/energy-efficient-buildings
3
) Eurostat 2019
4
) ECTP European Construction, built environment and energy efficient building Technology Platform
5
) RHC-ETIP European Technology and Innovation Platform on Renewable Heating and Cooling
4

---------------------- Page: 6 ----------------------
SIST CWA 17941:2022
CWA 17941:2022 (E)
• Information and communication technologies (ICT) tools for ground research and worksite
monitoring: non-invasive and integrated techniques for ground research, worksite and building
monitoring.
The following innovative technologies can be considered:
— Monitoring tools capable of assessing the stability of buildings involved in retrofitting
operations, for example Ground Based Interferometric Synthetic Aperture Radar (GBInSAR).
— Radar interferometry enabling 3-D spatial measurements.
— Ground Penetrating Radar (GPR), with automatic detection process.
— Interface between the GPR and Web Map Services (WMS) to download/upload the underground
asset maps before/after the survey.
— Building information modeling (BIM) integration of structural building monitoring tools during
drilling works.
— Drone monitoring.
• Drilling technologies: adapted to the context of SGE building retrofitting:
— Vertical drilling.
— Trenchless - horizontal directional drilling (HDD) techniques that enable the deployment of
horizontal loops like geothermal heat exchangers in this context.
• Geothermal/ground source heat exchangers (GHEX): with corresponding suitable configurations
for SGE building retrofitting and effective installation.
— Vertical borehole type heat exchangers.
— Earth basket and helical type heat exchangers.
— Shallow horizontal or slinky type heat exchangers.
• Ground Source Heat Pumps (GSHPs): optimized for the use of geothermal heat and building
retrofit applications. As existing buildings are less flexible compared to new buildings, this issue must
be addressed explicitly.
— Hybrid (thermally and electrically driven) heat pump (HP) system for high temperature lifts
which integrates better with a smaller GHEX compared to conventional systems.
— Electrically driven HP system for high temperature lifts which integrates better with a normal
sized GHEX.
— Integration of other RES (e.g., photovoltaic and solar thermal) to increase the total RES share.
• Heating and cooling solutions for energy-efficient building retrofitting.
— Easy-to-install and efficient heating solutions, for example low-temperature heating (LTH)
technology suitable for GSHPs.
5

---------------------- Page: 7 ----------------------
SIST CWA 17941:2022
CWA 17941:2022 (E)
— Easy-to-install and efficient cooling solutions, for example high-temperature cooling (HTC)
technology enables a high coefficient of performance (COP) of GSHPs used in building
retrofitting. The possibility to get cooling with direct use of the cold water in the bedrock can be
also considered, as a very energy efficient method where the only energy required is that
required to pump the liquid around.
• ICT based control systems and building energy management systems (BEMS) that enables the
full utilization of the EGS in retrofitted buildings by unlocking energy flexibility services using
demand side response techniques.
• BIM enabled tools for management of SGE building retrofitting.
Considering the interoperability of the aforementioned technologies, this document provides a
general methodological management framework using an Integrated Design and Delivery
Solutions (IDDS) approach for the SGE building retrofitting process, adaptable to project and site
specificities.
IDDS was launched in 2009 and developed as a new priority theme of the board of the worldwide CIB
organization (International Council for Research and Innovation in Building and Construction or “Conseil
6)
International du Bâtiment” in French). The CIB White Paper on IDDS defines it as “the use of
collaborative work processes and enhanced skills, with integrated data, information, and knowledge
management to minimize structural and process inefficiencies and to enhance the value delivered during
design, build, and operation, and across projects”.
This IDDS vision extends beyond new buildings to encompass modifications and upgrades, particularly
those aimed at improving local and area sustainability goals. IDDS will therefore facilitate greater
flexibility of design options, work packaging strategies and collaboration with suppliers and
tradespeople, which will be essential to meet evolving sustainability targets.
The four key IDDS elements are: collaborative processes across all project phases, enhanced skills of the
team, integrated information and automation systems, and knowledge management.

6
) Owen, R., Palmer, M., Dickinson, J.K., Tatum, B., Kazi, A.S., Amor, R., & Prins, M.M. (2009). CIB White Paper on IDDS
Integrated Design & Delivery Solutions [328].
6

---------------------- Page: 8 ----------------------
SIST CWA 17941:2022
CWA 17941:2022 (E)
1 Scope
This CEN Workshop Agreement (CWA) provides orientation for the management of building retrofitting
projects based on enhanced shallow geothermal technologies.
This document provides guidelines for the classification of an integrated design team and the
identification of the primary roles of actors among the whole project life-cycle. This document also
provides a general workflow for building retrofitting projects based on enhanced shallow geothermal
technologies, to be adapted or modified considering the specificities of each project requirements, and
site characteristics, and stakeholder profiles involved in the process.
This CWA is not designed to support European legislative requirements or to address issues with
significant health and safety implications. CEN and CENELEC are not accountable for its technical content
or any possible conflict with national standards or legislation.
2 Normative references
There are no normative references in this document.
3 Terms, definitions, and abbreviations
No terms and definitions are listed in this document.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
 ISO Online browsing platform: available at https://www.iso.org/obp/
 IEC Electropedia: available at https://www.electropedia.org/
BEMS Building energy management systems
BIM Building Information Modelling
BMS Building Management Systems
BPE Building performance evaluation
DHW Domestic Hot Water
EGS Enhanced Geothermal Systems
FEM Finite Element Method
GBInSAR Ground Based Interferometric Synthetic Aperture Radar
GHEX Ground Source Heat Exchanger
GPR Ground Penetrating Radar
GSHP Ground-Source Heat Pump
HP Heat Pump
HTC High-Temperature Cooling
HVAC Heating, Ventilation, and Air Conditioning
IDDS Integrated Design and Delivery Solutions
LTH Low-temperature Heating
RES Renewable Energy Source
SGE Shallow Geothermal Energy
7

---------------------- Page: 9 ----------------------
SIST CWA 17941:2022
CWA 17941:2022 (E)
4 Steps for an integrated approach
4.1 General
Building retrofitting is a complex and holistic process in which decisions should be taken by considering
a large diversity of constraints, stakeholders, and specific objectives.
The integrated IDDS-based approach of a SGE building retrofitting project comprises three major aspects:
people, processes, and technologies. For implementing the integrated approach of the project, three main
steps should be followed (see Figure 1 for an explanatory scheme):
• Building the project’s integrated team: The first step is to clearly identify the project team and to
classify these actors according to their expertise and skills.
• Defining project phases and identifying primary roles of the team members: This step aims to
define the main phases of the project and to identify the team responsibilities for each phase.
• Developing a collaborative workflow schedule: This phase aims to integrate all involved actors to
develop the workflow and dataflow and to implement the BIM platform for the project site.

Figure 1 — Main steps for implementing the integrated approach of a SGE building retrofitting
project
4.2 Building the integrated project design team
4.2.1 General
To support an integrated project approach, a building retrofit project should comply with systems
associated with different kinds of users. The four main actor categories in an integrated project are (1)
clients, (2) designers, (3) contractors, and (4) managers. Each of these categories encompass different
types of actors. They should establish a high-level of collaboration with one another to pursue common
objectives.
8

---------------------- Page: 10 ----------------------
SIST CWA 17941:2022
CWA 17941:2022 (E)
Within these four actor categories, those who should be considered at the earliest stage of a SGE building
retrofitting project are shown in Figure 2. A variety of views, scientific or technical approaches, objectives,
working methods, etc. are inherently present within a project. It is therefore necessary to define a
management framework in order to deal with this diversity, to keep focus on the essentials and to ensure
good communication between actors, to drive effective and collaborative work.

Figure 2 — Main categories and sub-categories of actors for a SGE building retrofitting project
4.2.2 Clients
In a SGE building retrofitting project, clients are broadly defined as the local stakeholders who are likely
to be directly or indirectly affected by the intervention (building occupants) and any individual or group
who may influence the management of the project. They can be for instance the building owners, the end
users, the building operators, or the facility managers. All these actor profiles could interact with the
building, its management and its systems after the project, and are therefore considered as clients using
the systems or services provided by the project.
Building owners: According to the Integrated Project Delivery (IPD) Guide (Richard Cook 2007),
building owners in particular take “an active role in evaluating and influencing design options”. In addition,
building owners may “participate to establish project metrics at an earlier stage than in a traditional
project” and will also “assist designers and constructors to solve issues”.
Building users: It is necessary to involve a representative of residents/building occupants/other
consumer-users of a building (or proxy thereof) who would be directly impacted by the retrofitting works
in terms of disturbance, comfort improvement, accessibility, aesthetics, etc. The local project partners
can facilitate the involvement of users and communicate relevant information to the project team. The
consultation should take into account both the likely lower technical knowledge of this group, and the
need for inclusive and accessible consultation processes.
9

---------------------- Page: 11 ----------------------
SIST CWA 17941:2022
CWA 17941:2022 (E)
Building operators or facility managers: Essential in SGE building retrofitting projects is the
involvement of building operators or facility managers. Commissioning, monitoring and especially
maintenance are critical during the retrofitting, but also during the building operation and the post-
occupancy phases. During the construction, they can act as material suppliers. After commissioning, at
least one person responsible for the building maintenance should be designated and trained accordingly
or, instead, one operator and maintainer (O&M) should be outsourced.
4.2.3 Designers
Designers can be cost consultants, architects, specialised engineers (structural, mechanical, civil,
environmental design and energy efficient design, geotechnical, soil, geothermal), commissioning
agencies and other specialists (ecologist, daylighting, marketing expert, surveyor, R&D, consultant office)
who take part in the design. As IDDS is a collaborative process, clients and contractors are also involved
in the design, but they are not the appointed designers.
Regulatory specialists/facilitators: should be designated within the project team to facilitate
communication between clients and regulatory authorities. A partner with appropriate knowledge of
local regulation is recommended for this role, with support from geothermal and drilling specialists, local
engineers and planning consultants (the latter are necessary in some countries).
Quality auditors and commissioning authorities: should be designated within the project team to
oversee process quality and adequate documentation management. These actors should work in
collaboration with the rest of the technical partners.
Cost consultants: should be designated within the project team to ensure that the budgeted costs are
compliant with the market trends. This task is normally undertaken by the role of a quantity surveyor in
many countries.
Architects and designers: are typically not very involved in a SGE building retrofitting project. More
involvement would be required if major façade elements are to be considered, if internal layout of the
systems is of high importance, or if it’s a major large scale renovation project. Otherwise, the technical
equipment is normally concentrated in a technical room of the building, and the only visible part of the
installation could be the distribution piping and the heat emitters, which are under the responsibility of
the building owners. On the other hand, the drilling activities and the installation of undergrounded heat
exchangers could affect the surrounding visual appearance. The aesthetic issues should be discussed with
the building owners and occupants.
Specialised engineers: the design team of a SGE building retrofitting project should include the
following specialised engineers:
— Ground specialists for ground detection, drilling and excavation works.
These specialists are required for surveying and producing utility maps for private engineering
companies, DOT and municipalities. The identification of underground utilities should include: the
collection of all information in the project area, the application for the intervention authorization
from the local municipality, the execution of the data collection on site, the analysis of the collected
data and localisation of features, the drafting of a report (including properly formatted computer-
aided design drawings), the execution of a field cross check to compare the achieved output
(cartography map) with real time radar data (if required), and the final delivery the project to the
client.
They are also required to measure possible displacement of the building/structures close to the area
where excavation will occur.
Within this actor category, rig designers and producers can be also considered for the rig and
ancillary equipment selection to get the optimal tool material and tool geometry.
10

---------------------- Page: 12 ----------------------
SIST CWA 17941:2022
CWA 17941:2022 (E)
— Specialists of ground heat exchangers design for shallow geothermal systems.
— Specialists of heating, ventilation, and air-conditioning (HVAC) facility design and sizing: geothermal
HPs, heat storage, hydronics, emitters…
— Specialists of control strategies and monitoring systems.
Control engineers or building management systems (BMS) integrators are required for controlling a
BMS. Electrical engineering specialists are required for studying the impact of the SGE systems on
the grid, since an increase in the peak capacity can be foreseen. They shall perform a study of the
available power and the maximum additional power for the HP system. It can be necessary or
recommended to modify a BMS to a building energy management system (BEMS). The best working
period for the HP can be indicated by estimating the required demand for the next period (typically
24 – 48h). This is intended for the system to use electricity when it is cheapest and to avoid additional
peaks on the import of net energy. When there is also local energy production (as with solar panels)
the surplus of electricity should be stored as heat in a buffer tank. This functionality can be added to
the local BMS or come from services in the cloud that analyse and predict consumption, production
and checks the available electricity prices on a contractual basis.
Additional specialists: BIM specialists, structural health survey specialists or demand response
specialists can be included in this actor category.
Regarding BIM specialists, a team focused on data curation and management is required for a digitalised
project. This team should also have expertise in internet of things (IoT), simulation and artificial
intelligence (AI) to support the creation of digital mirrors.
Regarding structural health survey specialists, it is recommended that they have expertise in:
— Design an excavation plans to avoid/limit vibration propagations during excavation – in cooperation
with a drilling company.
— Building monitoring during the excavation phase for rapid building health assessment before and
during drilling.
Other additional specialists can be required depending on the project specificities.
4.2.4 Contractors
Contractors are actors taking part in construction. They can be construction companies, a construction
manager, or equipment and material suppliers.
General contractors and specialised contractors: should have operational knowledge of the different
system parts. This category includes groundwork contractors, general building contractors, and
mechanical and electrical (M&E) contractors.
Industrial manufacturers and supply-chain vendors or distributors with technical sales who can
provide added value: the designer team of a SGE building retrofitting project should include suppliers of
the main components of the new SGE system (e.g., GSHPs, GHEXs, HVAC systems, monitoring and control
devices).
4.2.5 Managers
Managers are responsible for controlling and/or administering the entire project. Two types of managers
can be considered in an IDDS project: the IDDS facilitator, and the project manager or the building
program representative.
IDDS facilitators: provide guidelines for project management, “allowing team members to focus on their
tasks and goals, while at the same time fosterin
...