CEN/TR 15316-6-3:2017

Energy performance of buildings - Method for calculation of system energy requirements and system efficiencies - Part 6-3: Explanation and justification of 15316-3, Module M3-6, M4-6, M8-6

This Technical Report refers to standard EN 15316 3 1, modules Space Distribution Systems Module M3-6 heating / M4-6 cooling / M8-6 domestic hot water
It contains information to support the correct understanding, use and national adaptation of standard EN 15316-3-1.

Heizungsanlagen und Wasserbasierte Kühlanlagen in Gebäuden - Verfahren zur Berechnung der Energieanforderungen und Nutzungsgrade der Anlagen - Teil 6-3: Begleitende TR zur EN 15316-3 (Wärmeverteilungssysteme für die Raumheizung (Trinkwarmwasser, Heizen und Kühlen))

Performance énergétique des bâtiments - Méthode de calcul des besoins énergétiques et des rendements des systèmes - Partie 6-3 : Explication et justification de l’EN 15316-3, Module M3-6, M4-6, M8-6

Le présent Rapport technique fait référence à l’EN 15316 3, modules Systèmes de distribution des locaux, Module M3-6 chauffage/M4-6 refroidissement/M8-6 eau chaude sanitaire.
Il contient des informations permettant d’assurer une compréhension, une utilisation et une adaptation nationale correctes de la norme EN 15316 3.

Energijske lastnosti stavb - Metoda za izračun energijskih zahtev in učinkovitosti sistema - 6-3. del: Razlaga in utemeljitev EN 15316-3 - Moduli M3-6, M4-6 in M8-6

To tehnično poročilo (CEN/TR 15316-6-3) določa podrobnosti za standard EN 15316-3 in podaja dodatne informacije za uporabo standarda EN 15316-3.

General Information

• Status: Published
• Publication Date: 18-Apr-2017
• ICS: 91.120.10 - Thermal insulation of buildings
• ICS: 91.140.10 - Central heating systems
• ICS: 91.140.30 - Ventilation and air-conditioning systems
• ICS: 91.140.65 - Water heating equipment
• Technical Committee: CEN/TC 228 - Heating systems in buildings
• Drafting Committee: CEN/TC 228/WG 4 - Calculation methods and system performance and evaluation
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 19-Apr-2017
• Due Date: 15-Aug-2015
• Completion Date: 19-Apr-2017
• Directive: 2010/31/EU - Directive 2010/31/eu of the European Parliament and of the Council of 19 May 2010 on the energy performance of buildings (recast)
• Mandate: M/480 - Mandate to CEN, CENELEC and ETSI for the elaboration and adoption of standards for a methodology calculating the integrated energy performance of buildings and promoting the energy efficiency of buildings, in accordance with the terms set in the recast of the Directive on the energy performance buildings (2010/31/EU)
• Ref Project: SIST-TP CEN/TR 15316-6-3:2018 - Energy performance of buildings - Method for calculation of system energy requirements and system efficiencies - Part 6-3: Explanation and justification of 15316-3, Module M3-6, M4-6, M8-6

Standards Content (Sample)

SLOVENSKI STANDARD
01-maj-2018
(QHUJLMVNHODVWQRVWLVWDYE0HWRGD]DL]UDþXQHQHUJLMVNLK]DKWHYLQXþLQNRYLWRVWL
VLVWHPDGHO5D]ODJDLQXWHPHOMLWHY(10RGXOL00LQ0
Energy performance of buildings - Method for calculation of system energy requirements
and system efficiencies - Part 6-3: Explanation and justification of 15316-3, Module M3-
6, M4-6, M8-6
Heizungsanlagen und Wasserbasierte Kühlanlagen in Gebäuden - Verfahren zur
Berechnung der Energieanforderungen und Nutzungsgrade der Anlagen - Teil 6-3:
Begleitende TR zur EN 15316-3 (Wärmeverteilungssysteme für die Raumheizung
(Trinkwarmwasser, Heizen und Kühlen))
Performance énergétique des bâtiments - Méthode de calcul des besoins énergétiques
et des rendements des systèmes - Partie 6-2 : Explication et justification de l’EN 15316-
2, Module M3-5, M4-5
Ta slovenski standard je istoveten z: CEN/TR 15316-6-3:2017
ICS:
91.140.10 Sistemi centralnega Central heating systems
ogrevanja
91.140.65 Oprema za ogrevanje vode Water heating equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

CEN/TR 15316-6-3
TECHNICAL REPORT
RAPPORT TECHNIQUE
April 2017
TECHNISCHER BERICHT
ICS 91.120.10; 91.140.10; 91.140.30; 91.140.65
English Version
Energy performance of buildings - Method for calculation
of system energy requirements and system efficiencies -
Part 6-3: Explanation and justification of 15316-3, Module
M3-6, M4-6, M8-6
Performance énergétique des bâtiments - Méthode de Heizungsanlagen und Wasserbasierte Kühlanlagen in
calcul des besoins énergétiques et des rendements des Gebäuden - Verfahren zur Berechnung der
systèmes - Partie 6-2 : Explication et justification de Energieanforderungen und Nutzungsgrade der
l'EN 15316-2, Module M3-5, M4-5 Anlagen - Teil 6-3: Begleitende TR zur EN 15316-3
(Wärmeverteilungssysteme für die Raumheizung
(Trinkwarmwasser, Heizen und Kühlen))

This Technical Report was approved by CEN on 27 February 2017. It has been drawn up by the Technical Committee CEN/TC
228.
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, Serbia, 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
© 2017 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 15316-6-3:2017 E
worldwide for CEN national Members.

Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Symbols and abbreviations . 6
4.1 Symbols . 6
4.2 Subscripts . 7
5 Information on the methods . 7
6 Method description . 8
6.1 Thermal loss calculation and auxiliary energy in distribution systems . 8
6.1.1 Basic principles . 8
6.1.2 Ribbon heater in DHW distribution systems . 12
6.1.3 Auxiliary energy calculation . 12
6.1.4 Recoverable and recovered auxiliary energy . 16
6.1.5 Calculation of linear thermal resistance . 17
6.1.6 Time steps . 18
6.1.7 Assumptions . 18
6.1.8 Data input . 18
6.1.9 Simplified input . 18
7 Input correlations to the length of pipes in zones (buildings) . 19
7.1 Introduction . 19
7.2 Network for space heating and space cooling systems . 19
7.2.1 Sections . 19
7.2.2 Input data to the correlation . 20
7.2.3 Correlations. 20
7.2.4 Boundary conditions . 21
7.3 Network for domestic hot water systems . 21
7.3.1 Sections . 21
7.3.2 Input data to the correlation . 22
7.3.3 Correlations. 22
7.3.4 Boundary conditions . 23
8 Input correlations to linear thermal transmittance of pipes in zones (buildings) . 23
8.1 Introduction . 23
8.2 Network for space heating, space cooling and domestic hot water systems . 24
8.2.1 Sections . 24
8.2.2 Correlations. 24
9 Input correlations to constants for distribution pumps . 25
9.1 Introduction . 25
9.2 Constants for the calculation of the expenditure energy factor of distribution pumps . 25
10 Input correlations to additional resistances and resistance ratio . 26
10.1 Introduction . 26
10.2 Network for space heating, space cooling and domestic hot water systems . 26
10.2.1 Correlations for pressure loss per length . 26
10.2.2 Correlations for resistance ratio . 26
10.2.3 Correlations additional resistances . 27
10.2.4 Input correlations factor for recoverable auxiliary energy . 27
11 Worked out examples - Calculation details . 27
12 Application range . 27
12.1 Energy performance . 27
12.1.1 Thermal expenditure energy factor. 27
12.1.2 Primary energy related expenditure energy factor . 28
12.2 Energy certificate . 28
12.3 Inspection . 28
12.4 Building or system complexity . 28
13 Regulation use . 28
14 Quality issues . 28
Annex A (informative) Calculation example . 29
Annex B (informative) Data catalogue example . 39
Bibliography . 40

European foreword
This document (CEN/TR 15316-6-3:2017) has been prepared by Technical Committee CEN/TC 228
“Heating systems and water based cooling systems in buildings”, the secretariat of which is held by DIN.
This document has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
Introduction
The set of EPB standards, technical reports and supporting tools
In order to facilitate the necessary overall consistency and coherence, in terminology, approach,
input/output relations and formats, for the whole set of EPB-standards, the following documents and
tools are available:
a) a document with basic principles to be followed in drafting EPB-standards:
CEN/TS 16628:2014, Energy Performance of Buildings - Basic Principles for the set of EPB
standards [1];
b) a document with detailed technical rules to be followed in drafting EPB-standards;
CEN/TS 16629:2014, Energy Performance of Buildings - Detailed Technical Rules for the set of
EPB-standards [2];
c) the detailed technical rules are the basis for the following tools:
1) a common template for each EPB-standard, including specific drafting instructions for the
relevant clauses;
2) a common template for each technical report that accompanies an EPB standard or a cluster of
EPB standards, including specific drafting instructions for the relevant clauses;
3) a common template for the spreadsheet that accompanies each EPB standard, to demonstrate
the correctness of the EPB calculation procedures.
Each EPB-standards follows the basic principles and the detailed technical rules and relates to the
overarching EPB-standard, EN ISO 52000-1 [3].
One of the main purposes of the revision of the EPB-standards is to enable that laws and regulations
directly refer to the EPB-standards and make compliance with them compulsory. This requires that the
set of EPB-standards consists of a systematic, clear, comprehensive and unambiguous set of energy
performance procedures. The number of options provided is kept as low as possible, taking into
account national and regional differences in climate, culture and building tradition, policy and legal
frameworks (subsidiarity principle). For each option, an informative default option is provided
(Annex B).
Rationale behind the EPB technical reports
There is a risk that the purpose and limitations of the EPB standards will be misunderstood, unless the
background and context to their contents – and the thinking behind them – is explained in some detail
to readers of the standards. Consequently, various types of informative contents are recorded and made
available for users to properly understand, apply and nationally or regionally implement the EPB
standards.
If this explanation would have been attempted in the standards themselves, the result is likely to be
confusing and cumbersome, especially if the standards are implemented or referenced in national or
regional building codes.
Therefore each EPB standard is accompanied by an informative technical report, like this one, where all
informative content is collected, to ensure a clear separation between normative and informative
contents (see CEN/TS 16629 [2]):
— to avoid flooding and confusing the actual normative part with informative content;
— to reduce the page count of the actual standard; and
— to facilitate understanding of the set of EPB standards.
This was also one of the main recommendations from the European CENSE project [5] that laid the
foundation for the preparation of the set of EPB standards.
1 Scope
This Technical Report refers to standard EN 15316-3, modules Space Distribution Systems Module M3-
6 heating / M4-6 cooling / M8-6 domestic hot water
It contains information to support the correct understanding, use and national adaptation of standard
EN 15316-3.
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.
EN 15316-3, Energy performance of buildings - Method for calculation of system energy requirements and
system efficiencies - Part 3: Space distribution systems (DHW, heating and cooling), Module M3-6, M4-6,
M8-6
EN ISO 7345:1995, Thermal insulation - Physical quantities and definitions (ISO 7345:1987)
EN ISO 52000-1:2017, Energy performance of buildings - Overarching EPB assessment - Part 1: General
framework and procedures (ISO 52000-1:2017)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN ISO 7345:1995,
EN ISO 52000-1:2017 and the following apply.
3.1
tapping profile
depending on the definition in M8-3
3.2
setback
operation Mode for pumps at the end of scheduled usage time
3.3
boost
operation Mode for pumps before the begin of scheduled usage time
4 Symbols and abbreviations
4.1 Symbols
For the purposes of this Technical Report, the symbols given in EN ISO 52000-1:2017, in EN 15316-3
(the accompanied EPB standard) and the specific symbols listed in Table 1 apply.
Table 1 — Specific symbols and units
Symbol Name of quantity Unit
n Tapping profile 1/h
Tap
4.2 Subscripts
For the purposes of this Technical Report, subscripts given in EN ISO 52000-1:2017, in EN 15316-3 and
the specific subscripts listed in Table 2 apply.
Table 2 — Specific Subscripts
boost Boost heating dis Distribution W Operation mode
X,dis,aux
setb Setback mode dis Distribution W Operation mode
X,dis,aux
nom nominal heat loss dis Distribution Q
w,dis,nom
stub open circuited stubs dis Distribution Q
W,dis,stub
5 Information on the methods
The calculation of the thermal losses of pipes is well known and is used in this standard as a simplified
model without any dynamic aspects like heat capacity of the pipes und changing of transfer coefficients.
It is always taken into account that within a time step the heat flux from the mean water temperature in
the pipe to the surrounding room is constant.
In closed circuits like for space heating and space cooling the mean supply and mean return
temperature within a time step is constant.
In open circuits like in domestic hot water systems with a circulation loop the open circuited stubs the
temperature drops down depending on the time after a tapping. The calculation method in this
standard allows calculating the temperature after the last tapping and then a mean temperature in this
period without tapping. Because of the problem that the time after a tapping is mostly not known the
calculation method in this standard allows calculating the mean temperature directly as an
approximation depending on the thermal linear resistance.
In domestic hot water systems without a circulation loop the thermal loss of the hot water pipes in total
can be calculated like open circuited stubs either with the detailed calculation of the temperature after
the last tapping or with the approximation of the mean temperature depending on the thermal linear
resistance.
As long as the tapping profile only gives the number of tapping’s per day it is not possible to determine
the time after the last tapping. Therefore the approximation should prefer.
The calculation of the thermal resistance for insulated or not insulated pipes is well known and is given
in this standard for the most relevant cases. Depending on national regulations often minimum values
of thermal resistances are postulated so that in the standard values for the most relevant cases in the
pipe sections are given.
The equations in the standard refer to the length of the pipes in the corresponding section of the
network. If the length of the pipes is known the calculations are directly possible. In an early design
stage or in existing buildings the length of pipes is not known. Therefore is a method in the standard
developed where the length of pipes can be calculated depending on the size of the corresponding zone
(building).
The auxiliary energy in distribution systems for space heating or space cooling corresponds to the
circulation pumps. In distribution systems for domestic hot water the auxiliary energy is either the
energy for the circulation pump or for a ribbon heater.
The auxiliary energy for pumps depends very much from the part load operation. Europump, the
European Association of Pump Manufacturers, has established a common method to calculate the
expenditure energy for distribution pumps, so that this method is used in this standard. Meanwhile a
product label EEI (energy efficiency index) according to the EU regulations is available (not for all kind
of pumps – only for circulation pumps (wet running meter) in the range of 1 W to 2 500 W of hydraulic
power). If this EEI of a real pump is known in the standard a method is developed to take it into
account.
6 Method description
6.1 Thermal loss calculation and auxiliary energy in distribution systems
6.1.1 Basic principles
The input data are the actual input and output temperatures of the circuit as well as the volume flow
and the part load in the time step of calculation. The increasing fluid temperature in the circuit is not
calculates in this module.
The thermal loss of a pipe and the relevant values in a pipe section j are shown in Figure 1.

Key
1 Qdiss,ls 4 θmean
2 θamb 3 - Ψ
5 L 6 Pipe j
Figure 1 — Thermal loss of a pipe and relevant values
The thermal loss in a distribution system is calculated by the basic equation which for a pipe section
and a time step is given by:
Q ⋅⋅Ψθ − θ ⋅ LL+ ⋅ t [kWh] (1)
( )
( )
dis,ls mean amb equi c
where
θ [°C] is the surrounding temperature in the zone
amb
L [m] is the length of the pipe in the zone (unconditioned or conditioned)
Lequi [m] is the equivalent Length of the pipe for valves, hangers etc. in the zone
(unconditioned or conditioned)
t [h] is the time step
c
=
Ψ [W/mK] is the linear thermal resistance
In the standard the basic Formula (1) is only adapted to the different boundary conditions and also
completed with the summation over the different parts of the network where the boundary conditions
are constant (i.e. constant surrounding temperature, constant linear thermal resistance). Also a
summation over all time steps is added.
In distribution systems with closed loops for space heating and space cooling (see Figure 2) the mean
water temperature is represented by the mean value of the supply and return temperature and given
by:
θθ+
in out
θ = [°C] (2)
mean
Key
1 Emitter 6 W
X,dis,aux
2 θX,em,in 7 Δp

3 θX,em,out 8
V
4 QX,dis,ls 9 Generator / Storage Tank
5 L
max
Figure 2 — Distribution system for space heating or space cooling systems – closed loop (Index X
for H = heating; C = cooling)
In distribution systems for DHW with a circulation loop (see Figure 3) the mean water temperature is
given by:
∆θ
W
θθ − [°C] (3)
mean W
where
θ [°C] is the hot water temperature
W
=
∆θ [°C] is the temperature difference between hot water tapping temperature to the
W
return temperature in a circulation loop system

Key
1 θ 8 L
W max
2 θW,avg 9 WW,dis,aux
3 θW,atap 10 Δp
4 Q 11 
W,dis,stub
V
5 θ 12 θ
W W
6 Tap 13 θW - ΔθW
7 QW,diss,ls 14 Generator / Storage Tank
Figure 3 — Distribution system for DHW with circulation loop
The thermal loss of the circulation loop in a DHW system is similar to the distribution system for space
heating or space cooling as long the circulation loop is operating. The calculation of the thermal loss in
the circulation loop when the circulation is not operating is just similar. Only the mean water
temperature depends on the time after the last operation of the circulation. An additional thermal loss
for the open circuited stubs is given (see Figure 3) in the time when it is operating and in the time when
there is no tapping because the temperature drops down depending on the time after a the last tapping.
If the number of tapping’s and the volume of water within the pipes in the open circuited stubs are
known the mass flow can be calculated and under the assumption that between the tapping’s the hot
water temperature drops down to the surrounding temperature the thermal loss can be calculated by:
The mass flow of hot water in open circuited stubs mw,dis,stub during operation is given by:

m Vn⋅⋅ρ
W,,dis stub j W tap, j
∑
j
[kg/h] (4)
where
V [m ] is the volume of pipes in open circuited stubs per zone
ρ [kg/m ] is the density of water
W
ntap,j [1/h] is the number of tapings per zone
The additional thermal loss for distribution pipes with open circuited stubs Q per time step is
W,dis,stub
given by:

Q mc⋅⋅ θθ− ⋅ t
( )
Wd,,is stub Wd,,is stub w W Wa, mb, j ci
[kWh] (5)
where
c [kWh/kgK] is the specific heat of water
W
m [kg/h] is the mass flow of hot water in open circuited stubs
W,dis,stub
If the time after the last tapping or the last circulation in circulation loops is known it is possible to
calculate the temperature after the last tapping. In addition the heat capacity of the pipes and the heat
flow rate per length shall be known respectively shall be calculated.
The hot water temperature after a tapping during a time without operation θ is given by:
W,dis,atap
−C
i
θ θ +−θθ ⋅ e [°C] (6)
( )
W,dis,atap,i W,,ah j W W,amb, j
where
C [-] is the exponent in pipe section i (see Formula (13)
i
The exponent C for the calculation of the temperature drop after a tapping is given by:
i
q ⋅ Lt⋅
i i atap
C ⋅ (7)
i
c ⋅ ρ ⋅+V cm⋅
θθ−
W W i p pi,
( )
W W,,amb i
where
V [m ] is the volume of pipes in section i
c [kg/m ] is the specific heat of pipe
P
m [kg] is the mass of pipe in section i
P
t [h] is the time after a tapping before next tapping
atap
q [W/m] is the heat flow rate per length (see Formula (8)
i
The heat flow per length is given by:
[W/m] (8)
q=Ψθ⋅ − θ
( )
i i W W,,amb j
=
=
=
=
By knowing the temperature after a tapping the thermal loss of the open circuited stubs can be
calculated by Formula (1) using the mean temperature during the time of the last tapping and the start
of the next tapping. This mean temperature is given by:
θθ+
W W,,dis atap
θ = [°C] (9)
W,avg
The same calculation method can be used for domestic hot water systems without a circulation circuit.
In this case the pipe length is the total length of the pipes from the generator to the tap.
Q ⋅Ψ⋅ ϑ − ϑ ⋅+LL ⋅ t [kWh] (10)
( ) ( )
W,,dis nom j W,avg W,amb, j equi ci
j
If the tapping profile don’t give the information about the time after the last tapping and also the
dimension of the pipes aren’t known an approximation of the mean temperature in hot water pipes (see
Figure 3) without circulation is given by:
−0,2
θ θΨ25⋅ [°C] (11)
W,,em mean W,avg
With this approximation Formula (1) resp. (10) can directly be used.
The equations in the standard refer to the length of the pipes in the corresponding section of the
network. If the length of the pipes is known the calculations are directly possible. In an early design
stage or in existing buildings the length of pipes is not known. Therefore a method in the standard is
developed as an example where the length of pipes can be calculated depending on the size of the
corresponding zone (building).
The total thermal loss in a DHW distribution system in total (see Figure 3) is given by:
— Heat loss of circulation system during operation Q + heat loss of circulation system without
W,dis,ls
operation Q + thermal loss for distribution pipes with open circuited stubs Q
w,dis,nom W,dis,stub
[kWh] (12)
Q =Q ++Q Q
W,,dis ls,total W,,dis ls W,,dis nom W,,dis stub
6.1.2 Ribbon heater in DHW distribution systems
In domestic hot water systems sometimes the thermal losses of the pipes are compensated by a ribbon
heater. In this cases the auxiliary energy demand for a ribbon heater W is given by:
W,dis,rib
[kWh] (13)
WQ=
W,,dis rib W,,dis ls
where
Q [kWh] is the calculated according to Formula (1), taking into account only the length
W,dis.ls
of the hot water pipes.
6.1.3 Auxiliary energy calculation
The auxiliary energy in distribution systems with circuits is given by the electrical energy of the
circulation pumps.
Because of the same calculation method for the auxiliary energy of circulation pumps only the boundary
conditions are different. In space heating and space cooling systems the flow rate is depending on the
momentum power which has to deliver to the systems and the related supply and return temperature.
The momentum flow rates and the design flow rates are not calculated in this module.
= =
=
The differential pressure of a pipe system (delivery height) depends on the maximum length of the
pipes from begin to the most far end of the circuit, the pressure loss of the pipes and additional
resistances such as valves, flanges, fittings etc. Taking into account that the pressure loss of the pipes
are mean values in the whole network and that they are constant because of the dimensioning of the
diameters the calculation of the differential pressure Δ of the piping system in a zone is given by:
pX,des
∆∆p =1+ fR⋅ ⋅+L p [kPa] (14)
( )
X,des comp X,,max max X add
where
f [-] is the resistance ratio of components in the piping system see Annex C of
comp
the standard
R [kPa/m] is the pressure loss per length see Annex C of the standard
X,max
L [m] is the maximum length of the circuit
max
Δp [kPa] is the pressure losses of additional resistances see Annex C of the
X,add
standard
Formula (14) is valid for design conditions, which are responsible for designing the pump. The
differential pressure under operating conditions is proportional to the square of the flow.
As long as the maximum length of the pipes in the circuit is known Formula (14) can be used directly. In
case of an early design stage or on existing buildings the maximum length of pipes can be calculated
depending on the size of the corresponding zone (building).
The auxiliary energy calculation of distribution pumps is based on the hydraulic power at design
conditions and the part load conditions. The part load conditions are given by the variable flow in the
network which can be found according to the proportional laws. This leads in a net curve in operation
which is different from the design net curve.
At design point the pump has an efficiency which gives the relation between the hydraulic power to the
electrical power. Under operation conditions the electrical power depends on the control mode of the
pump (see Figure 4). If the pump has no speed control the operation point follows the pump curve to
operation point A, if the pump has a Δ – speed control the pump will operate at point B and if the
pconst
pump has a Δ – speed control the operation point is at point C (see Figure 4).
pvar
Key
1 pump curve 5 Δp [kPa]
2 net curve in operation A no control
3 designpoint B Δpconst
4 C Δpvar


m
V

h

Figure 4 — Pump and net curve with pump control mechanism
Under design conditions the hydraulic design power of a circulation pump P is given by:
X,hydr,des

∆pV⋅
des des
P = [kW] (15)
hydr,des
where
[kPa] is the differential pressure in a zone (piping system) at design point
Δpdes

[m /h] is the flow at design point
V
des
The hydraulic energy demand W under part load conditions is given by:
X,dis,hydr,an
[kWh] (16)
W P ⋅ β⋅ tf⋅
dis,,hydr an hydr,des dis op,an corr
where
ß [-] is the part load of the distribution system
dis
t [h] is the operation time of the distribution system
op,an
f [-] is the correction factor for special design conditions of the distribution
corr
system
The mean part load β of the distribution system is not calculated in this module-
dis
The part load conditions are calculated by a common method based on the hydraulic energy demand
and an expenditure energy factor of circulation pumps. The auxiliary energy demand W is given
dis,aux,an
by:
=
[kWh] (17)
W W ⋅ ε
dis,,aux an dis,hydr,an dis
where
ε [-] is the expenditure energy factor of the distribution pump
dis
The expenditure energy factor of circulation pumps ε is based on a common efficiency curve of
dis
pumps which is represented by a factor for efficiency. For part load conditions the expenditure energy
factor depends on the part load, two constants for the control mode and a factor taking into account real
product information:
EEI
−1
εβ=fC⋅ +⋅C ⋅ [-] (18)
dis e ( P12P dis )
0,25
where
f [-] is the factor for efficiency;
e
C [-] is the constant depending on control system of the pump – see Annex C
P1
C [-] is the constant depending on control system of the pump – see Annex C
P2
EEI [-] is the energy efficiency index taking into account product values of circulation
pumps.
The energy efficiency index of the real pump which is measured and labelled according to the EU-
regulation (ErP) is only available for circulation pumps in space heating or space cooling systems, not
for pumps in DHW distribution systems.
The factor for efficiency f in general is given by:
e
P
ref
f = [-] (19)
e
P
hydr,des
where
P [-] is the reference power of the pump
ref
For circulation pumps (wet running meter) with hydraulic power 0,001 < P < 2,5 kW the
HC,hydr,des
reference power is according to EU-Regulation Nr. 622/2012 given by:
 
−03, ⋅P
−3
HC,,hydr des
RP1,7⋅ + 17⋅−1 e ⋅ 10 [kW] (20)
 

HC,ref HC,,hydr des

 
For all other pumps in Formula (18) EEI shall set to EEI = 0,25 and the factor for efficiency f is then
e
given by:
05,


02.

f=1,25+⋅ b [-] (21)

e

P

hydr,des


where
b [-] is the factor for pump design selection.
If the pump is selected with operation point next to the design point the factor b is set to 1 otherwise
specially in existing buildings b is set to 2.
=
=
For existing installations, it is approximately correct to use the power rating given on the label at the
pump for (in case of non-controlled pumps with more than one speed level, shall be
P P
el,pmp el,pmp
taken from the speed level at which the pump is operated). Then the factor for efficiency is given by:
P
el,pmp
f = [-] (22)
e
P
HCW,,hydr des
where
P [kW] is the power rating on the label at existing pump (at speed level of pump
el,pmp
operation).
With this approximation the expenditure factor is to be calculated with Formula (18) and to set
EEI = 0,25 also.
For intermittent operation of circulation pumps in space heating or space cooling systems there are
three different phases:
— regular mode;
— setback mode;
— boost period.
For the setback operation the pump is operated at minimum speed, the power is assumed to be
constant 30 % of the electrical power at design point and then the auxiliary energy demand W ,
dis,aux,setb
taking into account a mean pump efficiency of 30 %, is given by:
[kWh] (23)
W Pt⋅
dis,,aux setb hdr,des c
For boost mode operation the power of the pump is the electrical power at design point. The auxiliary
energy demand W , also taking a mean pump efficiency into account, is given by:
X,dis,aux,boost
[kWh] (24)
W =33,⋅⋅Pt
dis,,aux boost hydr,des c
When the real power of the circulation pump in the different modes is available the calculation should
be use this data.
Calculation of recoverable thermal losses
The recoverable thermal loss of distribution systems for space heating, space cooling and DHW Q in
dis,rbl
the zone is given by Formula (12) under the boundary condition that the pipes with length L are
j
located in conditioned spaces. Therefore the recoverable thermal loss as a part f of the total losses
dis,rbl
is given as:
[kWh] (25)
Qf ⋅ Q
HW,,dis rbl HW _dis_rbl HW,,dis ls,total
Q =−⋅fQ [kWh] (26)
C,,dis rbl C _dis_rbl C,,dis ls,total
In case of distribution systems for space cooling the losses are negative which means that the energy
demand for cooling in the conditioned space is increased.
6.1.4 Recoverable and recovered auxiliary energy
The recoverable auxiliary energy for distribution systems for space heating and DHW Qdis,rbl as heat flux
to the zone is given by:
=
=
[kWh] (27)
Q fW⋅
dis,,rbl rbl dis dis
where
f [-] is the factor for recoverable auxiliary energy in distribution systems.
rbl,dis
For no insulated pumps the factor for recoverable auxiliary energy could set as an approximation to
0,25 and for insulated pumps to 0,1. Detailed product values are not available.
In case of distribution systems for space cooling the heat flux to the zone is given by using the same
factor for recoverable energy but becomes negative, so that the energy demand in the conditioned space
is increased:
[kWh] (28)
Q fW⋅
HW,aux,rbl rbl,dis HW,,dis aux
The recovered auxiliary energy for distribution systems for space heating and DHW Q in the
HW,dis,rvd
zone as heat flux to the fluid is given by:
Q =1−⋅f W [kWh] (29)
( )
HW,,dis rvd rbl,dis HW,,dis aux
In case of distribution systems for space cooling the heat flux to fluid in the zone is given by using the
same factor for recoverable energy but becomes negative, so that the energy demand for cooling the
fluid is increased:
Q =− 1− f ⋅ W [kWh] (30)
( )
C,aux,rvd rbl,dis C,,dis aux
6.1.5 Calculation of linear thermal resistance
The linear thermal transmittance Ψ for insulated pipes in air with a total heat transfer coefficient
including convection and radiation at the outside is given by:
π
Ψ = [W/m∙K] (31)
 
d
a
 ⋅+ln 
 
2 ⋅⋅λ d hd
D i a a
 
where
d , d [m] is the the inner diameter (without insulation) and outer diameter (with
i a
insulation) of the pipe;
h [W/(m K] is the outer total surface coefficient of heat transfer (convection and
a
radiation) – in most cases 8 W/(m K);
λ [W/mK] is the thermal conductivity of insulation.
D
For embedded pipes the linear thermal transmittance Ψ is given by:
em
π
Ψ = [W/m∙K] (32)
em

d
11 1 4 ⋅ z
a
⋅+ln ⋅ ln
2 λ ddλ

D i em a

where
z [m] is the the depth of pipe from surface;
λ [W/(mK)] is the thermal conductivity of embedded material.
em
=
=
For non-insulated pipes the linear thermal transmittance Ψ is given by:
non
π
[W/m∙K] (33)
Ψ =
non
d
11pa,
⋅+ln
2 ⋅⋅λ d hd
P pi,,a pa
where
d , d [m] is the the inner and outer diameter of the pipe;
p,i p,a
λ [W/mK] is the thermal conductivity of the pipe material.
P
As an approximation the linear thermal transmittance Ψ is given by:
non
Ψπh⋅ ⋅ d [W/m∙K] (34)
non a p,a
6.1.6 Time steps
The calculation method can be used with the following time steps:
— hourly;
— monthly;
— yearly.
The bin-method can also be used because in this method only identical time steps are summarized.
No dynamic effects are explicitly taken into account because there are no significant time constants.
6.1.7 Assumptions
In the simplified method for calculation the average temperature in DHW distribution systems (see
Formula (11) an approximation is used. These values are very close to the values when the calculation
is made according to Formulae (6) – (9) taking into account a time of approximately 3 h after last
tapping. If the exact time after the last tapping is not exactly known this simplification should be used.
This simplification is also very close to the method which was in Annex B of the former EN 15316-3-2.
To take into account the setback and boost mode for circulation pumps it is assumed that the power of
the pump in the setback mode is constant 30 % of the electrical power at design point and also a mean
pump efficiency of 30 %. For boost mode operation it is assumed that the power of the pump is the
electrical power at design point and also a mean pump efficiency of 30 %.
6.1.8 Data input
The input data are the operation conditions of temperatures and flows in the circuits and the control
modes of the pumps. If the length of pipes are not known input correlations are given as an example
depending on the size of the corresponding zone (building). Also if the detailed kind of insulation is not
known input correlations are given as standard values depending on the section in the network.
The product data for pumps – EEI – is taking into account if available (only for circulators (wet running
meter) in the range of 1 W to 2 500 W of hydraulic power).
6.1.9 Simplified input
In all basic equations for thermal distribution losses the length of pipes in the individual section i are
required. If this length is not known during the design process or measurement in existing buildings an
approximation depending on the size of the zone (building), the type of network and the section is given
as an example in C.1.
=
7 Input correlations to the length of pipes in zones (buildings)
7.1 Introduction
Losses of distribution subsystems are calculated summing the losses of each homogeneous section
according to the specific equations. This annex identifies:
types of distribution networks;
sections of the distribution networks type;
correlations to get the input data of the length of pipes for each section and type of distribution network
7.2 Network for space heating and space cooling systems
7.2.1 Sections
This type of network, shown in Figure 5 is divided in the following sections:
A connection of radiators to vertical shafts
S vertical shafts
V base distributor/collector
Key
1 Section A
2 Section S
3 Section V
A LL
B LW
C Hfl
Figure 5 — Typically network of space heating and space cooling systems
7.2.2 Input data to the correlation
Input data to the correlation (see Figure 5):
LL [m] is the length of the building;
LW [m] is the width of the building;
Hfl [m] is the floor height;
Nlev [-] is the number of floors (levels).
7.2.3 Correlations
For a block building the length of the pipes for each section is given by the following correlation tables.
In this table are also included the correlations for surrounding temperatures in each section.
Table 3 — Two-Pipe-Syste
...