CEN/TR 16798-6:2017

SLOVENSKI STANDARD
01-julij-2018
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LQ(10HWRGH]DL]UDþXQSRWUHEQHHQHUJLMH]DVLVWHPH
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Energy performance of buildings - Ventilation for buildings - Part 6: Interpretation of the
requirements in EN 16798-5 -1 and EN 16798-5-2 - Calculation methods for energy
requirements of ventilation and air conditioning systems (Modules M5-6, M5-8, M 6-5,
M6-8 , M7-5, M7-8)
Energieeffizienz von Gebäuden - Lüftung von Gebäuden - Teil 6: Interpretation der
Anforderungen der EN 16798-5-1 und EN 16798-5-2 - Berechnungsmethoden für den
Energiebedarf von Lüftungs- und Klimaanlagen (Module M5-6, M5-8, M6-5, M6-8, M7-5,
M7-8)
Performance énergétique des bâtiments - Ventilation des bâtiments - Partie 6 :
Interprétation des exigences de l'EN 16798-5-1 et de l'EN 16798-5-2 - Méthodes de
calcul des besoins énergétiques des systèmes de ventilation et de conditionnement d'air
(Modules M5-6, M5-8, M6-5, M6-8, M7-5, M7-8)
Ta slovenski standard je istoveten z: CEN/TR 16798-6:2017
ICS:
91.140.30 3UH]UDþHYDOQLLQNOLPDWVNL Ventilation and air-
VLVWHPL conditioning systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

CEN/TR 16798-6
TECHNICAL REPORT
RAPPORT TECHNIQUE
June 2017
TECHNISCHER BERICHT
ICS 91.120.10; 91.140.30
English Version
Energy performance of buildings - Ventilation for buildings
- Part 6: Interpretation of the requirements in EN 16798-5
-1 and EN 16798-5-2 - Calculation methods for energy
requirements of ventilation and air conditioning systems
(Modules M5-6, M5-8, M 6-5, M6-8 , M7-5, M7-8)
Performance énergétique des bâtiments - Ventilation Energieeffizienz von Gebäuden - Lüftung von
des bâtiments - Partie 6 : Interprétation des exigences Gebäuden - Teil 6: Interpretation der Anforderungen
de l'EN 16798-5-1 et de l'EN 16798-5-2 - Méthodes de der EN 16798-5-1 und EN 16798-5-2 -
calcul des besoins énergétiques des systèmes de Berechnungsmethoden für den Energiebedarf von
ventilation et de conditionnement d'air (Modules M5-6, Lüftungs- und Klimaanlagen (Module M5-6, M5-8, M6-
M5-8, M6-5, M6-8, M7-5, M7-8) 5, M6-8, M7-5, M7-8)

This Technical Report was approved by CEN on 27 February 2017. It has been drawn up by the Technical Committee CEN/TC
156.
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 16798-6:2017 E
worldwide for CEN national Members.

Contents Page
European foreword . 4
Introduction . 7
1 Scope . 9
2 Normative references . 9
3 Terms and definitions . 9
4 Symbols, subscripts and abbreviations. 9
4.1 Symbols . 9
4.2 Subscripts . 9
4.3 Abbreviations . 10
5 Brief description of the methods and routing . 10
5.1 Output of the methods . 10
5.2 General description of the methods . 10
5.2.1 Method 1 . 10
5.2.2 Method 2 . 11
5.3 Selection criteria between the methods . 11
5.4 Application and implementation of the methods . 12
5.4.1 Method 1 . 12
5.4.2 Method 2 . 13
6 Calculation method 1 (EN 16798-5-1) . 13
6.1 Output data . 13
6.2 Calculation time interval and calculation period . 13
6.3 Input data . 13
6.3.1 Source of data . 13
6.3.2 Product data . 14
6.3.3 System design data . 14
6.3.4 Operating conditions . 14
6.3.5 Constants and physical data . 14
6.4 Calculation procedure, method 1 . 15
6.4.1 Applicable calculation interval . 15
6.4.2 Distribution calculation . 15
6.4.3 Generation calculation . 18
7 Calculation method 2 (EN 16798-5-2) . 35
7.1 Output data . 35
7.2 Calculation interval . 35
7.3 Input data . 36
7.3.1 Source of data . 36
7.3.2 Product data . 36
7.3.3 System design data . 36
7.3.4 Operating conditions . 36
7.4 Calculation procedure . 36
7.4.1 Applicable timestep . 36
7.4.2 Operating conditions calculation . 37
7.4.3 Energy calculation . 39
8 Quality control . 43
9 Compliance check . 43
10 Worked out examples, method 1 . 43
10.1 Example 1 . 43
10.1.1 Description . 43
10.1.2 Calculation details . 47
10.1.3 Observations . 47
11 Worked out examples, method 2 . 48
11.1 Description . 48
11.2 Calculation details . 52
11.3 Observations . 52
12 Validation of the calculation procedures . 52
Annex A (informative) Input and method selection data sheet — Template . 53
A.1 General . 53
A.2 References . 53
A.3 Product description data . 53
A.4 Product technical data . 53
A.5 System design data . 53
Annex B (informative) Input and method selection data sheet — Default choices . 54
B.1 General . 54
B.2 References . 54
B.3 Product description data . 54
B.4 Product technical data . 54
B.5 System design data . 55
Annex C (informative) Calculation method for ground preheating and -cooling . 56
Annex D (informative) Calculation method for rotary heat exchangers . 58
D.1 Calculation. 58
D.2 Data . 58
Annex E (informative) Calculation examples . 59
E.1 Spreadsheet . 59
E.2 Example 1 (method 1) . 59
E.3 Example 2 (method 2) . 88
Bibliography . 118

European foreword
This document (CEN/TR 16798-6:2017) has been prepared by Technical Committee CEN/TC 156
“Ventilation for buildings”, the secretariat of which is held by BSI.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent
rights.
This document has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association.
The necessary editorial revisions were made to comply with the requirements for each EPB technical
report.
This document has been produced to meet the requirements of Directive 2010/31/EU 19 May 2010 on
the energy performance of buildings (recast), referred to as “recast EPDB”.
For the convenience of Standards users CEN/TC 156, together with responsible Working Group
Conveners, have prepared a simple table below relating, where appropriate, the relationship between
the ‘EPBD’ and ‘recast EPBD’ standard numbers prepared by Technical Committee CEN/TC 156
“Ventilation for buildings”.
EPBD EN Recast EPBD EN
Title
Number Number
Energy performance of buildings – Ventilation for buildings –
Part 1: Indoor environmental input parameters for design
EN 15251 EN 16798-1 and assessment of energy performance of buildings
addressing indoor air quality, thermal environment, lighting
and acoustics (Module M1-6)
Energy performance of buildings – Ventilation for buildings –
Part 2: Interpretation of the requirements in EN 16798-1 –
Indoor environmental input parameters for design and
N/A CEN/TR 16798-2
assessment of energy performance of buildings addressing
indoor air quality, thermal environment, lighting and
acoustics (Module M1-6)
Energy performance of buildings – Ventilation for buildings –
Part 3: For non-residential buildings – Performance
EN 16798-3
requirements for ventilation and room-conditioning systems
EN 13779
(Modules M5-1, M5-4)
Energy performance of buildings – Ventilation for buildings –
Part 4: Interpretation of the requirements in EN 16798- 3 –
N/A CEN/TR 16798-4 For non-residential buildings – Performance requirements
for ventilation and room-conditioning systems (Modules M5-
1, M5-4)
Energy performance of buildings – Ventilation for buildings –
Part 5-1: Calculation methods for energy requirements of
ventilation and air conditioning systems (Modules M5-6, M5-
EN 15241 EN 16798-5-1
8, M6-5, M6-8, M7-5, M7-8) – Method 1: Distribution and
generation
Energy performance of buildings – Ventilation for buildings –
Part 5-2: Calculation methods for energy requirements of
ventilation systems (Modules M5-6.2, M5-8.2) – Method 2:
EN 15241 EN 16798-5-2
Distribution and generation
Energy performance of buildings – Ventilation for buildings –
Part 6: Interpretation of the requirements in EN 16798-5–1
N/A CEN/TR 16798-6 and EN 16798-5-2 – Calculation methods for energy
requirements of ventilation and air conditioning systems
(Modules M5-6, M5-8, M 6-5, M6-8 , M7-5, M7-8)
Energy performance of buildings – Ventilation for buildings –
Part 7: Calculation methods for the determination of air flow
EN 15242 EN 16798-7
rates in buildings including infiltration (Module M5-5)

Energy performance of buildings – Ventilation for buildings –
Part 8: Interpretation of the requirements in EN 16798-7 –
N/A CEN/TR 16798-8
Calculation methods for the determination of air flow rates in
buildings including infiltration – (Module M5-5)
Energy performance of buildings – Ventilation for buildings –
EN 15243 EN 16798-9 Part 9: Calculation methods for energy requirements of
cooling systems (Modules M4-1, M4-4, M4-9) – General
Energy performance of buildings – Ventilation for buildings –
Part 10: Interpretation of the requirements in EN 16798-9 –
Calculation methods for energy requirements of cooling
N/A CEN/TR 16798-10
systems (Module M4-1,M4-4, M4-9) – General

Energy performance of buildings – Ventilation for buildings –
EN 15243 EN 16798-13 Part 13: Calculation of cooling systems (Module M4-8) –
Generation
Energy performance of buildings – Ventilation for buildings –
EN 15243 CEN/TR 16798-14 Part 14: Interpretation of the requirements in EN 16798-13 –
Calculation of cooling systems (Module M4-8) – Generation
Energy performance of buildings – Ventilation for buildings –
N/A EN 16798-15 Part 15: Calculation of cooling systems (Module M4-7) –
Storage
Energy performance of buildings – Ventilation for buildings –
N/A CEN/TR 16798-16 Part 16: Interpretation of the requirements in EN 16798-15 –
Calculation of cooling systems (Module M4-7) – Storage
Energy performance of buildings – Ventilation for buildings –
EN 15239 and
EN 16798-17 Part 17: Guidelines for inspection of ventilation and air-
EN 15240
conditioning systems (Module M4-11, M5-11, M6-11, M7-11)
Energy performance of buildings – Ventilation for buildings –
Part 18: Interpretation of the requirements in EN 16798-17 –
N/A CEN/TR 16798-18
Guidelines for inspection of ventilation and air-conditioning
systems (Module M4-11, M5-11, M6-11, M7-11)

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]; and
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, and
3) a common template for the spreadsheet that accompanies each EPB standard, to demonstrate
the correctness of the EPB calculation procedures.
Each EPB standard follows the basic principles and the detailed technical rules and relates to the
overarching EPB-standard, EN ISO 52000-1:2017 [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.
This Technical Report
This Technical Report accompanies the suite of EPB standards on the calculation of the energy
performance of ventilation systems. It relates to the European standards EN 16798-5-1 and
EN 16798-5-2, which form part of a set of standards related to the evaluation of the energy
performance of buildings (EPB).
The role and the positioning of the accompanied standards in the set of EPB standards is defined in the
Introduction to the standards.
Accompanying spreadsheet(s)
Concerning the accompanied standards EN 16798-5-1 and EN 16798-5-2, the following spreadsheets
were produced:
— on EN 16798-5-1; and
— on EN 16798-5-2.
In this Technical Report, examples of each of these calculation sheets are included.
1 Scope
This Technical Report refers to standards EN 16798-5-1 and EN 16798-5-2.
It contains information to support the correct understanding and use of these standards.
This Technical Report does not contain any normative provision.
2 Normative references
Not applicable.
NOTE More information on the use of EPB module numbers for normative references between EPB standards
is given in CEN ISO/TR 52000-2:2017.
3 Terms and definitions
For the purposes of this document, the terms and definitions as mentioned and given in the
EN 16798-5-1 and EN 16798-5-2 apply.
More information on some key EPB terms and definitions is given in CEN ISO/TR 52000-2:2017.
4 Symbols, subscripts and abbreviations
4.1 Symbols
For the purposes of this document, the symbols as mentioned and given in EN 16798-5-1 and
EN 16798-5-2 apply.
More information on key EPB symbols is given in CEN ISO/TR 52000-2:2017.
NOTE If new symbols are needed, indeed, please refer to the EPB standards template and Annex C of
EN ISO 52000-1:2017 for detailed rules.
Additional symbols are given in Table 1.
Table 1 — Symbols and units
Symbol Quantity Unit
u damper position —
γ concentration various
4.2 Subscripts
For the purposes of this document, the subscripts as mentioned and given in EN 16798-5-1 and
EN 16798-5-2 apply.
More information on key EPB subscripts is given in CEN ISO/TR 52000-2:2017.
NOTE If new subscripts are needed, indeed, please refer to the EPB standards template and Annex C of
EN ISO 52000-1:2017 for detailed rules.
Additional subscripts are given in Table 2.
Table 2 — Subscripts
Subscript Term
Bal balanced
D damper
F fan
Fld full load
Gas going to the gas
R resistance
SP setpoint
4.3 Abbreviations
For the purposes of this document, the abbreviations as mentioned and given in EN 16798-5-1 and
EN 16798-5-2 apply.
More information on key EPB abbreviations is given in CEN ISO/TR 52000-2:2017.
NOTE If new abbreviations are needed, indeed, please refer to the EPB standards template and Annex C of
EN ISO 52000-1:2017 for detailed rules.
Additional abbreviations are given in Table 3.
Table 3 — Abbreviations
Abbreviation Term
C Central controller
CR Zone based controller
R Resistance
VOC Volatile oxide components
5 Brief description of the methods and routing
5.1 Output of the methods
The accompanied EPB standards, EN 16798-5-1 and EN 16798-5-2, cover two different methods for the
calculation of the energy performance of ventilation and/or air conditioning systems.
Because the scope and the applicability range of the two methods are different, it was decided to divide
the description in two separate documents.
5.2 General description of the methods
5.2.1 Method 1
The method covers the calculation of:
— the volume flow rates provided to the ventilation zones served by the system, based on the
required values;
— the supply air temperature and moisture content, based on the required values;
— the ventilation generation input (electric energy required by fans);
— the humidification generation input;
— heating (including humidification in case of reheat with adiabatic humidification) and cooling input
to the air handling unit (to be transferred to the connected heating and cooling distribution systems
calculation);
— the recoverable heat or cold losses from ventilation/air conditioning system for heating or cooling;
— the ventilation auxiliary energy (electric energy for drives of, e.g. rotary or pumped circuit heat
recovery devices, control devices, actuators, etc.);
— the electric energy required for humidification (only for specific humidifier types); and
— the humidification auxiliary energy.
The time interval of the output can be:
a) hourly, or
b) bin,
according to the application of the standard and interval of the input.
5.2.2 Method 2
The method covers the calculation of:
— the volume flow rates provided to a single ventilation zone (no multi ventilation zones modelling)
served by the system, based on the required values;
— the supply air temperature, based on the required values;
— the ventilation generation input (electric energy required by fans);
— heating and cooling input to the air handling unit (to be transferred to the connected heating and
cooling distribution systems calculation);
— the recoverable heat or cold losses from ventilation/air conditioning system for heating or cooling;
and
— the ventilation auxiliary energy (electric energy for drives, control devices, actuators, .).
The time interval of the output can be:
a) monthly,
b) yearly, or
c) bin,
according to the application of the standard and time interval of the input.
5.3 Selection criteria between the methods
The criteria for the selection are:
— the technologies covered by the methods; and
— the calculation interval.
Method 1 is applicable for full air conditioning systems, including heating, cooling, humidification,
dehumidification, covering different control options such as constant and variable air volume flow
rates, different fan controls, different heat recovery types with different frost protection technologies,
constant and variable recirculation air, and adiabatic cooling. It is mainly dedicated to larger
customized air handling units and distribution networks. It can only be applied to hourly calculation
intervals and – with the respective technique provided – with bins.
Method 2 is applicable for ventilation systems with heating and cooling, including heat recovery and
recirculation. It does, however, not cover humidification and dehumidification. On the other hand, it
covers the use of extract air heat as a source of heat for domestic hot water production and includes the
heat generation by heat pumps. It is dedicated to packaged systems including heat generation and/or
DHW production, as they are mainly used in residential buildings. But the application is by intention not
restricted though the building use type. The method can be applied to monthly and yearly calculation
intervals and bins.
5.4 Application and implementation of the methods
5.4.1 Method 1
The method contains a lot of options, the choice of which needs to be made, in order to consider:
— different air treatment stages, which may or may not be present in the system to be represented
(e.g. recirculation, heat recovery, heating, cooling, humidification, dehumidification, adiabatic
cooling);
— different types of components for certain treatment stages (e.g. heat recovery types, humidifier
types); and
— different control options.
In the implementation of the method in the accompanying spreadsheet [3], a “system configuration”
sheet was added. It allows making the relevant choices, which influence the calculation procedure, as
shown in Figure 1.
The layout of the choices refers to the scheme shown above, which originates from Figure 1 in
EN 16798-5-1:2017.
Some choices of the presence of principal treatment stages are controlled by the presence of the
respective energy supply at the data input interface (heating, cooling), or by the presence of the
respective set points at the respective data input interface (humidification, dehumidification). This
means, no special keywords and identifiers are present in the standard for the choice of these options.
Figure 1 — System configuration table from the spreadsheet
5.4.2 Method 2
The method contains a lot of options, the choice of which needs to be made in order to consider
different air treatment stages, which may or may not be present in the system to be represented (e.g.
recirculation, heat recovery, heating, cooling).
In the implementation of the method in the accompanying spreadsheet, all relevant choices, which
influence the calculation procedure, have their input in the “Input_series” sheet and “Method_input”
sheet.
6 Calculation method 1 (EN 16798-5-1)
6.1 Output data
No further explanations.
6.2 Calculation time interval and calculation period
The method described in Clause 6 is mainly suitable for an hourly calculation interval. For the
application to bins, see 6.4.1.
6.3 Input data
6.3.1 Source of data
This method covers a large variety of technologies and design options. Accordingly, the amount of
required input data and option choices is also large.
For the typical type of systems the method is designed for, the respective data may be available from
design and/or maintenance documents, since these systems are usually operated by professional
facility managers.
However, there may be cases where it is difficult or impossible to get the respective data in a reasonable
amount of time. For these cases, the recommendation is to refer to the default values in Annex B of
EN 16798-5-1:2017, or to a respective national Annex provided. The latter may be necessary due to
differences in the frequency of technologies used in specific countries.
In special cases, the amount of data are reduced by the choice of a specific technology. For example, a
plate heat exchanger for the heat recovery requires drastically less input data than other types. Also, the
abandonment of specific technologies on a national basis may lead to a reduced amount of necessary
input data.
6.3.2 Product data
6.3.2.1 Product description data (qualitative)
No further explanations.
6.3.2.2 Product technical data
6.3.2.2.1 General
No further explanations.
6.3.2.2.2 Duct leakage factors
The duct leakage factors can be precalculated according to Formulae (1) and (2), based on measured
data according to product related standards (EN 14239, EN 12237 and EN 1507, depending on the form
of the ducts).
In the absence of detailed information, tabled duct leakage factors can be used depending on the duct
air tightness class.
6.3.2.2.3 Air handling unit leakage factors
In a similar way the air handling unit leakage factor can be precalculated in Formula (3), based on data
according to EN 1886.
In the absence of detailed information, tabled duct leakage factors can be used depending on the AHU
air tightness.
6.3.3 System design data
6.3.3.1 Process design
No further explanations.
6.3.3.2 Control
No further explanations.
6.3.4 Operating conditions
No further explanations.
6.3.5 Constants and physical data
No further explanations.
6.4 Calculation procedure, method 1
6.4.1 Applicable calculation interval
This procedure has been designed and tested for an hourly calculation interval.
For the application to bins, as indicated in EN 16798-5-1, it may be necessary to provide bins for several
independent operational and boundary condition parameters. For example, volume flow rate may vary
with the heating/cooling load, the outdoor proportion depends on the occupation, and the system is
dependent on the outdoor temperature via the heat recovery operation. This leads to a multi-
dimensional matrix of bins. The process for the generation of these bins is rather complex. Therefore it
may in many cases be simpler to do a sequential hourly calculation.
6.4.2 Distribution calculation
6.4.2.1 Operating conditions calculation
6.4.2.1.1 Volume flow rates
6.4.2.1.1.1 Detailed calculation
For this calculation, the supply and extract volume flow rates to and from the specific ventilation zones
are required inputs from the emission calculation (module 5-5). If they are not available, the simplified
calculation according to 6.4.2.1.1.2 is applied.
The required volume flow rates to be provided by the air handling unit to the distribution duct system
are modified by the leakage of the duct system (Formulae (4)a) and (5a)).
The supply volume flow rate really entering the distribution system and the extract volume flow rate
really leaving the distribution system are calculated further down in the generation part (Formulae (23)
and (24), 6.4.3.2.1), depending on the control type. They are generally not equal to the required flow
rates; for some control options they are.
The volume flow rates supplied to and extracted from specific ventilation zones served by the system
are calculated by distributing the real supply/extract flow rates proportionally to the required flow
rates (Formulae (6) and (7)). This is a simplification and may not occur precisely in practise, due to the
different pressure drops in the different branches.
The leakage volume flow rates going to or extracted from a specific zone are calculated with
Formulae (8) and (9). The zone can be a ventilation zone or a thermal zone. They are needed for the
mass flow balance in the zone (module 5-5). The supply leakage flow rate is also needed to calculate the
thermal losses due to the leakage, recoverable in the specific thermal zone (Formulae (21) and (22), see
6.4.2.2). Recoverable heat losses are recoverable in a thermal zone. Therefore, this term is used here.
For the distinction between the ventilation zone and thermal zone see EN ISO 52000-1:2017, Clause 10
(where the ventilation zone is called a service area) and 6.4.2.1.2, including the example in Figure 2. The
leakage volume flow rate going to the non-conditioned space calculated in Formula (10) leads to a non-
recoverable thermal loss (Formula (21)).
The maximum volume flow rate factor f calculated in Formula (11)a) is needed later for the fan
V;max
energy calculation (6.4.4.1)
6.4.2.1.1.2 Simplified calculation
For this calculation, instead of the individual supply and extract volume flow rates to and from the
specific thermal zones, only the part load factor and the diversity of the flow rates for the current time
step are required inputs.
The volume flow rates required to be provided by the air handling unit to the distribution duct system
are calculated with the part load factor of the current time step and the maximum (design) supply and
extract volume flow rates of the system in Formulae (4)b) and (5)b).
The maximum volume flow rate factor f is calculated in Formula (11)b) with the current part load
V;max
factor and the volume flow rate diversity Δf at the current time step, which is a required local input.
V
6.4.2.1.2 Air temperature and humidity change in the ductwork
These calculations are restricted to situations with overpressure in the supply and underpressure in the
extract air system, leading to a leakage flow rate going from the supply air system to its surrounding
and from the surrounding to the extract air system (not vice versa, the normal situation with balanced
air systems with air handling units and ductwork).
Both the required and the real supply air temperatures are modified in the duct due to the thermal
losses of the ducts (Formulae (12) and (13)).
Again, the distinction is made between the temperature drop in the non-conditioned space
(Formula (14)) and the one to the conditioned thermal zones (Formula (15)). The calculation is given
only for one specific zone.
Both the required and actual supply air humidity content remain unchanged (Formulae (16) and (17)).
For the extract air, only the leakage and the transmission heat exchange from the unconditioned space
is taken into account. It is assumed that the extract air temperature is close enough to the conditioned
zone temperatures to neglect these effects in the conditioned zones (Formulae (18) and (19)).
For the humidity content of the extract air, there is an additional contribution from the non-conditioned
surroundings due to the entering leakage flow rate (Formula (20)).
There are a lot of different possible situations, with different ventilation and thermal zones. Therefore it
is not possible to give a general method to cover all situations. The general method is explained with an
example shown in Figure 2.
Figure 2 — Ventilation and thermal zone example
In this example, an air handling unit (AHU) is situated in a non-conditioned space. It serves the
ventilation zone zv. In EN ISO 52000-1:2017, the entity called here a ventilation zone is referred to as a
ventilation service area.
The supply and extract ducts are crossing the non-conditioned space, a thermal zone zt , not served by
the ventilation system, and finally the thermal zone zt , which is identical to the ventilation zone zv
served by the system.
In this setup, the system has:
— a leakage flow from the AHU to the non-conditioned space; the losses associated to this are not
recoverable;
— a leakage flow from the supply air duct to the non-conditioned space; the losses associated to this
are not recoverable;
— thermal losses from the supply air duct to the non-conditioned space; they are not recoverable;
— a leakage flow from the supply air duct to the conditioned thermal zone zt ; the losses associated to
this are recoverable in thermal zone zt ;
— thermal losses from the supply air duct to the conditioned thermal zone zt ; they are recoverable in
thermal zone zt ;
— a leakage flow from the supply air duct to the ventilation zone zv (identical to the conditioned
thermal zone zt ); the flow is considered in the air flow balance of ventilation zone zv, and the
losses associated to this are recoverable in thermal zone zt ;
— thermal losses from the supply air duct to the ventilation zone zv (identical to the conditioned
thermal zone zt ); they are recoverable in thermal zone zt ;
1 1
— thermal losses from the extract air duct to the non-conditioned space; they are not recoverable;
— a leakage flow to the extract air duct from the conditioned thermal zone zt ; this is accounted for in
the mass balance of the system, the losses associated to this are neglected;
— thermal losses from the extract air duct to the conditioned thermal zone zt ; they are neglected;
— a leakage flow to the extract air duct from the ventilation zone zv (identical to the conditioned
); the flow is considered in the air flow balance of ventilation zone zv and of the
thermal zone zt1
system, and the losses associated to this are neglected; and
— thermal losses from the extract air duct to the ventilation zone zv (identical to the conditioned
thermal zone zt ); they are neglected.
In order to calculate this, the system should be considered in different parts. The leakage flow rates and
temperature differences are calculated separately for each piece situated in a diff
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