SIST CWA 16975:2017

Eco-efficient Substations for District Heating

The target is to describe what is an eco-efficient substation (EES), how this eco-efficient substation is considered, tested and certified. EES concept includes as much substation efficient design as possible, without trying to cover an exhaustive point of view. The scope of the EES is to focus on a reachable future, realistic compliance with the existing system and ways of handling substation issues in a harmonized manner across Europe.
The proposed standard is compliable with the expected development in Europe in the future such as:
•   New buildings with less demand for energy and more demands for lower temperatures.
•   The connection systems should be standardized in order to make the substation replacement as easy as possible.
The aim is to consider the whole life of the system, including all seasons and not only the peak load operation. The most important period to consider, is the long duration time with both heating and domestic hot water demands.
EES should be certified, and marked according to certification that is given according to testing result and environmental ranking. Only EES with capacity up to 500kW per heat exchanger for heating and domestic hot water respectively, can be certified. Small substations intended for single-family houses or flats, shall not be certified. A certificate can include one specific substation or a series of substations.
This document contains 3 main parts:
Technical: Describes the main and optional components of the EES
Environmental: Describes the various parameter and components that give the efficiency to the substation, how these are ranked and the marking procedure
Testing and certification: The testing and certification procedures.

Öko-effiziente Unterstationen

Eko učinkovite postaje za daljinsko ogrevanje

Cilj je opisati, kaj je eko učinkovita postaja (EES), ter opredeliti postopke obravnave, preskušanja in certificiranja eko učinkovite postaje. Koncept eko učinkovite postaje vključuje kar se da učinkovito načrtovanje postaje, pri čemer ne poskuša zajeti celotnega vidika načrtovanja postaje. Cilj eko učinkovite postaje je osredotočanje na dosegljive cilje v prihodnosti, dejansko skladnost z obstoječimi sistemi in usklajene načine obravnavanja težav postaj v celotni Evropi.
Predlagani standard je skladen s pričakovanim prihodnjim razvojem v Evropi, kar vključuje:
• Nove stavbe bodo porabljale manj energije in sistemi za nizkotemperaturno ogrevanje bodo bolj razširjeni.
• Priključitvene sisteme je treba standardizirati, da se omogoči lažja zamenjava postaj.
Cilj je upoštevati celotno življenjsko dobo sistema, vključno z vsemi letnimi časi, in ne samo obdobja delovanja pod največjo obremenitvijo. Najpomembnejše obdobje, ki ga je treba upoštevati, je dolgo obdobje s povečanim ogrevanjem in potrebami po topli sanitarni vodi.
Eko učinkovite postaje je treba certificirati in ustrezno označiti skladno s certifikatom, ki je izdan na podlagi rezultatov preskusov in razvrstitve glede na okoljski vpliv. Certificira se lahko samo eko učinkovite postaje z zmogljivostjo do 500 kW na toplotni prenosnik za ogrevanje in sanitarno toplo vodo. Majhne postaje, namenjene enodružinskim hišam ali stanovanjem, ne bodo certificirane. Certifikat lahko vključuje posamezno postajo ali skupino postaj.
Ta dokument je sestavljen iz treh glavnih delov:
Tehnični del: opisuje glavne in izbirne komponente eko učinkovite postaje.
Okoljski del: opisuje različne parametre in komponente, ki zagotavljajo učinkovitost postaj, njihovo razvrstitev glede na okoljski vpliv ter postopek označevanja.
Preskušanje in certificiranje: opisuje preskusne postopke in postopke certificiranja.

General Information

• Status: Published
• Publication Date: 27-Sep-2017
• ICS: 27.010 - Energy and heat transfer engineering in general
• ICS: 91.140.10 - Central heating systems
• Technical Committee: I13 - Imaginarni 13
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 27-Sep-2017
• Due Date: 02-Dec-2017
• Completion Date: 28-Sep-2017
• Ref Project: CWA 16975:2015 - Eco-efficient Substations for District Heating

RELATIONS

• Corrected By: SIST CWA 16975:2017/AC:2017 - Eco-efficient Substations for District Heating
• Effective Date: 27-Jul-2016

Standards Content (sample)

SLOVENSKI STANDARD
SIST CWA 16975:2017
01-november-2017
(NRXþLQNRYLWHSRVWDMH]DGDOMLQVNRRJUHYDQMH
Eco-efficient Substations for District Heating
Öko-effiziente Unterstationen
Ta slovenski standard je istoveten z: CWA 16975:2015
ICS:
27.010 Prenos energije in toplote na Energy and heat transfer
splošno engineering in general
91.140.10 Sistemi centralnega Central heating systems
ogrevanja
SIST CWA 16975:2017 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST CWA 16975:2017
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SIST CWA 16975:2017
CEN
CWA 16975
WORKSHOP
December 2015
AGREEMENT
ICS 27.010; 91.140.10
English version
Eco-efficient Substations for District Heating

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,

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 worldwide for CEN national Members.

Ref. No.:CWA 16975:2015 E
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CWA 16975:2015 (E)
Contents
Page

European Foreword ........................................................................................................................................................................4

1 Scope ........................................................................................................................................................................................5

2 Conformance .......................................................................................................................................................................5

3 Technical Part.....................................................................................................................................................................8

3.1 Introduction.........................................................................................................................................................................8

3.2 Terms and definitions....................................................................................................................................................8

3.3 Eco-efficient substation (EES) definition .........................................................................................................10

3.3.1 General.................................................................................................................................................................................10

3.3.2 Marking of EES.................................................................................................................................................................11

3.3.3 Commissioning, service and maintenance of EES.......................................................................................11

3.3.4 Choice of materials .......................................................................................................................................................11

3.4 Connection principles and standardized schemes ....................................................................................12

3.4.1 General Scheme of a substation ............................................................................................................................12

3.4.2 Parallel connection.......................................................................................................................................................12

3.4.3 Two step connection ....................................................................................................................................................12

3.5 Efficiency of Substation ..............................................................................................................................................13

3.5.1 Temperature and pressure levels in DH network......................................................................................13

3.5.2 Low temperature system ..........................................................................................................................................14

3.5.3 Pressure drop ..................................................................................................................................................................14

3.5.4 Efficiency of heat exchangers .................................................................................................................................15

3.5.5 Procedure to determine heat exchanger return temperature (T12)................................................15

3.6 Domestic hot water system......................................................................................................................................16

3.6.1 Functionalities.................................................................................................................................................................16

3.6.2 Choice of materials .......................................................................................................................................................17

3.6.3 Temperatures, Environmental and Health Requirements for the domestic hot water .......17

3.6.4 Dimensioning ...................................................................................................................................................................17

3.7 Heating systems..............................................................................................................................................................17

3.7.1 Dimensioning of Heat Exchangers for heating services..........................................................................17

3.7.2 Temperature levels for heating systems .........................................................................................................18

3.8 Control system and communication...................................................................................................................18

3.8.1 General.................................................................................................................................................................................18

3.8.2 Delivered heat control ................................................................................................................................................18

3.8.3 DHW control system ....................................................................................................................................................18

3.8.4 Accuracy of control system ......................................................................................................................................19

3.8.5 Advanced features.........................................................................................................................................................19

3.9 Substation components -including heat exchanger, pump, safety equipment, valves .........20

3.9.1 Generalities about the components....................................................................................................................20

3.9.2 Filter ......................................................................................................................................................................................21

3.9.3 Control valve ....................................................................................................................................................................21

3.9.4 Piping ....................................................................................................................................................................................21

3.9.5 Sensors.................................................................................................................................................................................21

3.9.6 Pumps:..................................................................................................................................................................................22

3.10 Insulation: ..........................................................................................................................................................................22

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4 Environmental Part ......................................................................................................................................................22

4.1 Environmental part General ...................................................................................................................................22

4.2 Heat losses in substation...........................................................................................................................................23

4.3 Pressure losses in secondary side heating .....................................................................................................24

4.4 Cooling of the return temperature ......................................................................................................................24

4.4.1 General.................................................................................................................................................................................24

4.4.2 Demands to Space Heating .......................................................................................................................................25

4.4.3 Demands to DHW...........................................................................................................................................................26

4.5 Energy saving functions .............................................................................................................................................27

4.5.1 General.................................................................................................................................................................................27

4.5.2 Control and limitation of max capacity / primary flow...........................................................................27

4.5.3 Indoor temperature data ..........................................................................................................................................27

4.5.4 Remote monitoring and control ...........................................................................................................................28

4.5.5 Eco function.......................................................................................................................................................................28

4.6 Labelling system.............................................................................................................................................................29

4.6.1 Eco-efficient substation labelling system and summary of rating points in case of

DHW and spice heating side(s)..............................................................................................................................29

4.6.2 Eco-efficient substation labelling system and summary of rating points in case of

only spice heating side(s) .........................................................................................................................................30

5 Testing and certification part.................................................................................................................................31

5.1 Certification process....................................................................................................................................................31

5.1.1 Introduction......................................................................................................................................................................31

5.1.2 Object ....................................................................................................................................................................................31

5.1.3 General rules ....................................................................................................................................................................31

5.1.4 Administration, Organisation ................................................................................................................................32

5.1.5 Certification procedure..............................................................................................................................................32

5.1.6 Conditions for certification and quality marking .......................................................................................34

5.2 Testing procedures.......................................................................................................................................................37

5.2.1 Assumption and preparations ...............................................................................................................................37

5.2.2 Test methods ....................................................................................................................................................................44

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SIST CWA 16975:2017
CWA 16975:2015 (E)
European Foreword

CWA 16975 is a technical agreement, developed and approved by an open, independent Workshop

structure within the framework of the CEN-CENELEC system. CWA 16975 reflects the agreement only

of the registered participants responsible for its content, and was developed in accordance with the

CEN-CENELEC rules and practices for the development and approval of CEN/CENELEC Workshop

Agreements. CWA 16975 does not have the status of a European Standard (EN) developed by CEN and

its national Members. It does not represent the wider level of consensus and transparency required for

a European Standard (EN) and is not intended to support legislative requirements or to address issues

with significant health and safety implications. For these reasons, CEN are not accountable for the

technical content of CWA 16975 or for any possible conflicts with national standards or legislation. The

Workshop participants who drafted and approved CWAWS 73 are indicated in the Foreword. The

copyright in CWA VW 73 is owned exclusively by CEN. Copies of CWA VS 73 are available from the

[national standards bodies of the following countries: 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.

Foreword

CWA 16975 was developed in accordance with CEN-CENELEC Guide 29 “CEN/CENELEC Workshop

Agreements – The way to rapid agreement” and with the relevant provisions of CEN/CENELEC Internal

Regulations - Part 2. It was agreed on 2015-09-11 in a Workshop by representatives of interested

parties, approved and supported by CEN following a public call for participation made on 2015-09-11. It

does not necessarily reflect the views of all stakeholders that might have an interest in its subject

matter.

The final text of CWA 16975 was submitted to CEN for publication on 2015-11-19. It was developed and

approved by: Paolo Arrus - Giacomini, Anna Boss - SP Swedish National Testing and Research Institut,

Aleš Cjuha - Energetika Ljubljana, Daniele Delboca - Giacomini, Mieczyslaw Dzierzgowski - OPEC

Gdynia, Bertrand Guillemot- Dalkia France, Niklas Jeppsson - SWEP International, Markus Köfinger -

AIT, Alexander Midtsjø - Hafslund Varme, Gunnar Nilsson - Svensk Fjärrvärme, Timo Peltola-Ouman,

Igor Radovic - Grundfos Holding, Fabrice Renaude - Gylergie Cofely's Research Center, Henrik Rietz -

SWEP International, Marko Riipinen - Helsinki Energy, Janusz Rozalski - OPEC Gdynia, Jaroslaw

Szczechowiak - OPEC Gdynia, Jan Eric Thorsen – Danfoss, Jonas Wallenskog - Svensk Fjärrvärme, Wim

Wolfs- Giacomini, Teijo Aaltonen - Alfa Laval Nordic.

It is possible that some elements of CWA 16975 will be subject to patent rights. The CEN-CENELEC

policy on patent rights is set out in CEN-CENELEC Guide 8 “Guidelines for Implementation of the

Common IPR Policy on Patents (and other statutory intellectual property rights based on inventions)”.

CEN shall not be held responsible for identifying any or all such patent rights.

The Workshop participants have made every effort to ensure the reliability and accuracy of the

technical and non-technical content of CWA 16975, but this does not guarantee, either explicitly or

implicitly, its correctness. Users of CWA 16975 should be aware that neither the Workshop participants,

nor CEN can be held liable for damages or losses of any kind whatsoever which may arise from its

application. Users of CWA 16975 do so on their own responsibility and at their own risk.

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SIST CWA 16975:2017
CWA 16975:2015 (E)
1 Scope

The target is to describe what is an eco-efficient substation (EES), how this eco-efficient substation is

considered, tested and certified. EES concept includes as much substation efficient design as possible,

without trying to cover an exhaustive point of view. The scope of the EES is to focus on a reachable

future, realistic compliance with the existing system and ways of handling substation issues in a

harmonized manner across Europe.

The proposed standard is compliable with the expected development in Europe in the future such as:

• New buildings with less demand for energy and more demands for lower temperatures.

• The connection systems should be standardized in order to make the substation replacement

as easy as possible.

The aim is to consider the whole life of the system, including all seasons and not only the peak load

operation. The most important period to consider, is the long duration time with both heating and

domestic hot water demands.

EES should be certified, and marked according to certification that is given according to testing result

and environmental ranking. Only EES with capacity up to 500kW per heat exchanger for heating and

domestic hot water respectively, can be certified. Small substations intended for single-family houses or

flats, shall not be certified. A certificate can include one specific substation or a series of substations.

This document contains 3 main parts:
Technical: Describes the main and optional components of the EES

Environmental: Describes the various parameter and components that give the efficiency to the

substation, how these are ranked and the marking procedure
Testing and certification: The testing and certification procedures.
2 Conformance

All DH equipment and the system as a whole shall be approved in accordance with international,

European Union and national laws, regulations, building codes and standards. In addition, all laws and

rules from the national health and environmental authorities shall be taken into consideration.

National DH organizations and Euroheat & Power should make efforts towards harmonizing such rules

and standards throughout the EU, in order for these rules and standards to be as much as possible in

line with the characteristics of DH. The aforementioned organizations may also issue technical

recommendations themselves.
The following EU directives and standards are relevant for this document:

• Directive 2012/27/EU (EED directive): Energy efficiency directive introduces a framework of

measures to use energy more efficiently at all stages of energy chain. The directive is especially

focused on energy efficiency improvements in households, industry and transport sector.

• Directive 2010/31/EU (EPBD directive): Energy performance of buildings directive introduces

the new methodology for calculating the energy efficiency of buildings, minimum requirements

for energy efficiency of new and renovated buildings, minimum requirements for energy

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CWA 16975:2015 (E)

efficiency of building equipment, plans for implementing more nearly zero energy buildings,

regular inspections of heating and air conditioning systems in buildings and implementation of

energy performance certificates for buildings.

• Directive 2010/30/EU: Directive establishes a framework for labelling and introducing

general product information on consumption of energy and other energy-related products.

• Directive 2009/125/EC: Directive represents a framework for minimum Eco design

requirements of product that use energy and water (light bulbs, refrigerators, heat Owen,

insulation materials, etc.).

• Regulation No. 641/2009 with amending regulation No. 622/2012 and regulation No.

547/2012: Regulations present eco-design requirements for water pumps.
• Directive 2004/22/EC (MID directive): Measuring instrument directive specifies

methodology and requirements for measuring instruments such as heat, water, gas and electric

energy meters, exhaust gas analysers, taximeters, etc.

• Directive 98/83/EC (DWD directive): Drinking water directive sets the minimum standards for

quality of drinking water in distribution systems, regarding microorganisms and chemical

parameters.

• Directive 97/23/EC (PED directive): Pressure equipment directive presents requirements for

design and fabrication of pressure equipment such as pressure vessels, piping, safety valves and

other components subjected to pressure load.

• Regulation EC 66/2010 (ECO labelling): Regulation presents rules for application of voluntary

environmental labelling system for eco-friendly products.
• European standard EN 1434 (Heat meters standard): Standard specifies minimum

requirements for heat meters regarding construction, data exchange, testing, verification,

installation, commissioning, monitoring and maintenance.

• European standard EN 13445 (Pressure vessels standard): Standard specifies requirements for

design, construction, inspection and testing of unfired pressure vessels made from steel, cast

iron and aluminium.

• European standard EN 1148:1998, EN 1148:1998/A1:2005 (Heat exchangers standard):

Standard specifies test procedures for establishing the performance data of water to water heat

exchangers for district heating.

• European standard EN 247:1997 (Heat exchangers standard): Standard specifies heat

exchangers terminology.

• European standard EN 12828:2012 (Heating systems in buildings standard): Standard specifies

the design of water based heating systems.

• European standard EN 14336:2004 (Heating systems in buildings standard): Standard specifies

the installation and commissioning of water based heating systems.
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• European standard EN 15316 series (Heating systems in buildings standard): Standard

specifies methods for calculation of system energy requirements and system efficiencies; with

special focus on Part 4-5 'Space heating generation systems, the performance and quality of

district heating and large volume systems.

All electrical components of the EES shall be electrically protected according to the applicable rules.

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3 Technical Part
3.1 Introduction

The aim of this part is to describe the technical specifications that a substation has to fulfil to be

regarded as an Eco-efficient substation.
3.2 Terms and definitions

Here is a simplified drawing of a substation that gives the location of the various components described

in the definition.
District Heating
Customer side
T T
11 42
DH supply
DHW supply T° DHW
T° supply
T DHW
41 T
Pressure Supply PS 61
DHW Circulation (T° C)
Cold water (T° CW)
SUBSTATION
T22
Heating supply
DH return T° HS
Heating
12 T
T° return
PR Pressure return Heating return
T° HR
Figure 1 - Definition drawing
DHW: Domestic Hot Water: Water heated for sanitary use.

DHW circulation loop: Piping where DHW continuously flows in order to keep the system active and the

temperature on such a level that both comfort and health requirements are delivered to the customer.

Cold Water: Is the fresh water coming from the water services that feed the DHW system.

DH: District Heating Network.
ΔP: Pressure difference between supply and return pipes.
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Definition of variables in a counter-flow heat exchanger
T Primary supply temperature from DH,
11 :
T Heating supply temperature, to customer,
22:
T Primary return temperature to DH,
12:
T21: Heating return temperature, from customer,
T DHW: Primary supply temperature from DH,
31:
T DHW supply temperature to customer,
42:
T DHW Primary return temperature to DH,
32:
Figure 2 - Variables in a heating counter-flow
heat exchanger
T DHW cold water and circulation loop temperature,
41:
ΔΤ2 Temperature difference secondary side,
T51: Cold Water temperature,
T61: Circulation loop return temperature,
ϑ Temperature difference heating (T12–T21) or DHW
side (T32– T41),
ϑ2 Temperature difference Primary side (T11–T22) or (T31–
T ).
Figure 3 - Variables in a DHW counter-flow heat
exchanger
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In this document, the following verbal forms are used:
• “Shall” indicates a requirement
• “Should” indicates a recommendation;
• “May” indicates a permission;
• “Can” indicates a possibility or a capability.
3.3 Eco-efficient substation (EES) definition
3.3.1 General

The purpose of this document is to describe what an Eco-efficient substation is. The substation is the

system in a district heating network, that connects the customer or group of customers to the network.

It complies with European and local regulations. Many various system designs are existing and this

document will describe those that provide the best ratio between energy efficiency, life cycle cost, the

most common use and new services that the substation might provide.

The EES provides both heat service (HS) and domestic hot water production (DHW) or the systems

might be considered separately if just one of the two is needed. It is suitable to consider Rehva request

and/or bacteriological risks according to national regulations when DHW is planned and installed.

To be efficient the Eco-efficient Substation (EES) shall deliver a reasonably low return temperature to

the network and create a reasonably low pressure drop across the system on the secondary side.

The EES shall be equipped to provide the customer and the district heating company with a secure,

energy effective and economically reliable connection to the DH-network. To achieve this target, the

EES shall include at least:

• One efficient heat exchanger per service such as brazed heat exchanger or any other

technology that provide the similar efficient service.
• Each heat exchanger shall be insulated.

• Control valve to control the energy delivered and control the temperature delivered to the

customer in an as efficient manner as possible. A control valve for temperature control

acts on the primary side for each service, heating and DHW.
• Filter should be installed on primary side
• Heat meter should be mounted according to EN 1434.

The number, quality and range of the devices shall be adjusted to the size of the substation. EES shall be

insulated to prevent heat losses, risk of injury and high ambient temperature in the substation room.

Other components can increase the scope of the services of the EES, but as they are strongly linked to

where they have to be implemented in the sizing and design, they are not in the scope of this document.

These components are for exam
...