ISO/TR 52016-2:2017

Energy performance of buildings - Energy needs for heating and cooling, internal temperatures and sensible and latent heat loads - Part 2: Explanation and justification of ISO 52016-1 and ISO 52017-1

ISO/TR 52016-2:2017 contains information to support the correct understanding and use of ISO 52016‑1 and ISO 52017‑1. These documents give calculation methods for the assessment of: - the (sensible and latent) energy load and need for heating and cooling, based on hourly calculations; - the (sensible and latent) energy need for heating and cooling, based on monthly calculations (ISO 52016‑1); - the internal temperature, based on hourly calculations; and - the design (sensible and latent) heating and cooling load, based on hourly calculations. ISO/TR 52016-2:2017 does not contain any normative provisions. NOTE A description of the rationale behind the reorganization of the cluster of strongly related and partly overlapping ISO and CEN standards is given in Annex H.

Performance énergétiques des bâtiments — Besoins d'énergie pour le chauffage et le refroidissement, les températures intérieures et les chaleurs sensible et latentes — Partie 2: Explication et justification pout ISO 52016-1 et ISO 52017-1

General Information

• Status: Published
• Publication Date: 20-Jun-2017
• ICS: 91.120.10 - Thermal insulation of buildings
• Technical Committee: ISO/TC 163/SC 2 - Calculation methods
• Drafting Committee: ISO/TC 163/SC 2/WG 15 - Energy Performance calculation methods
• Current Stage: 6060 - International Standard published
• Start Date: 21-Jun-2017
• Completion Date: 13-Dec-2025

Overview

ISO/TR 52016-2:2017 is an informative ISO Technical Report that explains and justifies the calculation approaches given in ISO 52016‑1 and ISO 52017‑1 for the energy performance of buildings. It does not introduce normative requirements; instead it provides background, rationale, worked examples and guidance to support correct use of the hourly and monthly calculation methods for: energy needs and loads for heating and cooling (sensible and latent), internal temperatures, and design heating/cooling loads.

Key topics and technical content

The report organizes and clarifies the methods and assumptions used in ISO 52016‑1 and ISO 52017‑1. Major subjects covered include:

• Scope, terms and definitions, and lists of symbols, subscripts and abbreviations to ensure consistent use of terminology.
• Description of output data: energy needs, hourly and monthly outputs, and peak design loads.
• Hourly calculation procedures (detailed routing of models from inputs to hourly outputs): thermal zoning, heat transfer, internal and solar gains, ventilation, moisture (latent heat) loads, and internal environment thermal capacity.
• Monthly calculation procedures: simplified monthly energy need computations, utilization factors, intermittency corrections and overheating indicators.
• Input data and assumptions: geometrical and thermophysical properties, boundary and operating conditions, and selection templates.
• Zoning and thermal coupling: guidance on zone size, heat exchange between zones and unconditioned spaces.
• Validation, verification and quality control: BESTEST-related verification cases, compliance checks, worked examples and reporting templates (Annexes A & B).
• Annex H (noted) explains the rationale for reorganization of related ISO/CEN standards.

Practical applications

ISO/TR 52016-2:2017 is a supporting document for practical building energy assessment and modeling tasks:

• Interpreting and applying ISO 52016‑1 (hourly and monthly calculation methods) and ISO 52017‑1 (reference hourly method).
• Ensuring consistent inputs and assumptions for energy performance certifications, compliance checks and design studies.
• Guiding development and validation of building simulation software and calculation tools.
• Informing HVAC design for accurate determination of sensible and latent heating/cooling loads and internal temperature predictions.

Who should use this standard

• Building energy modelers and simulation engineers
• HVAC designers and load calculation specialists
• Energy assessors and certification bodies
• Software developers creating compliant calculation tools
• Researchers and policymakers working on building energy performance standards

Related standards

• ISO 52016‑1 (calculation methods for energy needs - hourly and monthly)
• ISO 52017‑1 (reference hourly method) Note: ISO/TR 52016‑2 provides explanation and justification to support correct use of these standards rather than new normative requirements.

Keywords: ISO/TR 52016-2:2017, energy performance of buildings, heating and cooling energy needs, hourly and monthly calculations, sensible and latent heat loads, internal temperatures, ISO 52016‑1, ISO 52017‑1.

Standards Content (Sample)

TECHNICAL ISO/TR
REPORT 52016-2
First edition
2017-06
Energy performance of buildings —
Energy needs for heating and cooling,
internal temperatures and sensible
and latent heat loads —
Part 2:
Explanation and justification of ISO
52016-1 and ISO 52017-1
Performance énergétiques des bâtiments — Besoins d’énergie pour
le chauffage et le refroidissement, les températures intérieures et les
chaleurs sensible et latentes —
Partie 2: Explication et justification pout ISO 52016-1 et ISO 52017-1
Reference number
©
ISO 2017
© ISO 2017, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. [phone]
Fax [phone]
[e-mail]
www.iso.org
ii © ISO 2017 – All rights reserved

Contents Page
Foreword .vi
Introduction .vii
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols, subscripts and abbreviations . 2
4.1 Symbols . 2
4.2 Subscripts . 2
4.3 Abbreviations . 3
5 Brief description of the method(s) and routing . 3
5.1 Output of the method . 3
5.1.1 Reference hourly method in ISO 52017‑1 . 3
5.1.2 Hourly method in ISO 52016‑1 . 3
5.1.3 Monthly method in ISO 52016‑1 . 3
5.1.4 Overall and partial energy performance . 4
5.2 General description of the methods in ISO 52016-1 and ISO 52017-1 . 4
5.2.1 Hourly calculation procedures in ISO 52016‑1 and ISO 52017‑1 . 4
5.2.2 The hourly method in ISO 52017‑1 . 4
5.2.3 The hourly method in ISO 52016‑1 . 5
5.2.4 Monthly calculation procedures in ISO 52016‑1 . 7
5.2.5 Other differences between ISO 52016-1 and ISO 13790:2008 which
it supersedes . 7
5.2.6 Input data and assumptions for hourly and monthly method in ISO 52016‑1 . 8
5.2.7 Choices between methods in ISO 52016-1 . 8
6 Calculation method in ISO 52016-1 . 8
6.1 Output data . 8
6.1.1 General data on the assessed object and application . 8
6.1.2 Calculated data . 9
6.2 Calculation time intervals and calculation period . 9
6.3 Input data . 9
6.3.1 Source of data - General . 9
6.3.2 Deviating subscripts . 9
6.3.3 General data on the assessed object and application . 9
6.3.4 Geometrical characteristics .10
6.3.5 Thermophysical parameters of the building and building elements .10
6.3.6 Loops between input and output variables .11
6.3.7 Operating and boundary conditions .11
6.3.8 Constants and physical data.12
6.3.9 Input data from Annex A (Annex B) .12
6.4 Zoning of the assessed object .12
6.4.1 General.12
6.4.2 Thermal zoning procedures .12
6.4.3 Size of the thermal zones .13
6.4.4 Heat exchange between thermal zones and service areas .13
6.4.5 Adjacent thermally unconditioned zones.14
6.4.6 Residential buildings or building units, adjustment for spatial
average temperature .15
6.4.7 Thermally coupled or uncoupled zones .18
6.5 Hourly calculation procedures .19
6.5.1 Principle .19
6.5.2 Applicable time interval and calculation period .19
6.5.3 Assumptions and specific conditions .19
6.5.4 Calculation procedure .19
6.5.5 Calculation of (sensible) heating and cooling loads and temperatures .20
6.5.6 Overall energy balance of a thermal zone .21
6.5.7 Type of construction dependent properties of the nodes .25
6.5.8 Thermal transmission properties .25
6.5.9 Temperature of adjacent thermally unconditioned zone .28
6.5.10 Ventilation heat transfer coefficient, supply temperature and moisture content 28
6.5.11 Thermal capacity of the internal environment of the thermal zone .29
6.5.12 Internal heat gains .29
6.5.13 Solar gains .29
6.5.14 Moisture content and latent heat load .29
6.5.15 Calculation of key monthly data from hourly output .30
6.6 Monthly calculation procedures .30
6.6.1 Principle .30
6.6.2 Applicable time interval and calculation period .30
6.6.3 Assumptions .31
6.6.4 Energy need for space heating and cooling .31
6.6.5 Heat transfer by transmission .32
6.6.6 Heat transfer by ventilation .35
6.6.7 Internal heat gains .35
6.6.8 Solar heat gains .35
6.6.9 Internal effective heat capacity of a zone .35
6.6.10 Utilization factors .36
6.6.11 Calculation temperature and intermittency modes .37
6.6.12 Corrections for intermittency .38
6.6.13 Overheating indicator . .46
6.6.14 Length of the heating and cooling season for operation of season-length-
dependent provisions .47
6.6.15 Humidification and dehumidification .47
7 Quality control in ISO 52016-1 .48
7.1 Calculation report .48
7.2 Hourly method: verification cases .48
7.2.1 Choice for BESTEST cases .48
7.2.2 Description of the verification test cases .49
7.2.3 Results of the verification test cases .49
7.2.4 Comparison with available BESTEST results of other programs .49
7.2.5 Limited scope .49
7.2.6 Specific deviations allowed.49
7.2.7 Availability of the data file with hourly values .50
7.2.8 More details on description of the verification test cases .50
7.2.9 Results of comparison with “reference” programs .50
7.2.10 Peak hourly loads .51
7.3 Hourly method: validation in case of specific alternative calculation procedures .52
7.4 Specific validation cases.52
7.4.1 Heat transfer through ground floor .52
7.4.2 Solar shading .52
8 Compliance check in ISO 52016-1 .52
9 Worked out examples on ISO 52016-1 .53
9.1 Example 1 .53
9.1.1 Description . . .53
9.1.2 Description of construction elements of envelope .53
9.1.3 Calculation details .59
9.1.4 Remarks and comments .59
9.2 Example 2 .59
9.2.1 Description . . .59
9.2.2 Description of construction elements of envelope .60
9.2.3 Other data .62
iv © ISO 2017 – All rights reserved

9.2.4 Calculation details .62
9.2.5 Remarks and comments .62
10 Validation of the calculation procedures .62
Annex A (informative) ISO 52016-1: Input and method selection data sheet — Template .63
Annex B (informative) ISO 52016-1: Input and method selection data sheet — Default choices .64
Annex C (informative) ISO 52016-1: Regional references in line with ISO Global relevance policy 67
Annex D (informative) ISO 52016-1: Multi-zone calculation with thermal coupling
between zones .68
Annex E (informative) ISO 52016-1: Heat transfer and solar heat gains of windows and
special elements.69
Annex F (informative) ISO 52016-1: Calculation of solar shading reduction factors .78
Annex G (informative) ISO 52016-1: Dynamic transparent building elements.89
Annex H (informative) Rationale behind reorganization of suite of standards .90
Annex I (informative) Discussion on the hourly versus the monthly calculation methods in
ISO 52016-1 .95
Annex J (informative) Accuracy of the methods in ISO 52016-1 .104
Annex K (informative) Explanation and derivation of monthly utilization factors .110
Annex L (informative) Calculation examples .120
Bibliography .126
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO’s adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following
URL w w w . i s o .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 163, Thermal performance and energy
use in the built environment, Subcommittee SC 2, Calculation methods, in cooperation with the European
Committee for Standardization (CEN) Technical Committee CEN/TC 89 Thermal performance of
buildings and building components, in accordance with the Agreement on technical cooperation between
ISO and CEN (Vienna Agreement).
A list of all parts in the ISO 52016 series can be found on the ISO website.
vi © ISO 2017 – All rights reserved

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,
[1]
Energy Performance of Buildings — Basic Principles for the set of EPB standards ;
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-
[2]
standards .
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-standard follows the basic principles and the detailed technical rules and relates to the
[3]
overarching EPB-standard, ISO 52000-1 .
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
[2]
contents (see CEN/TS 16629 ):
— 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 [ ] that laid the
foundation for the preparation of the set of EPB standards.
This document
This document accompanies ISO 52016-1 and ISO 52017-1, 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 accompanying standards in the set of EPB standards is defined in
the Introduction to the standards.
[50] [51]
Brief articles on the subject can be found in to .
Accompanying spreadsheets
An extensive spreadsheet was produced on ISO 52016‑1, covering both the hourly and the monthly
calculation method. Examples of the calculation sheet can be found in this document. This spreadsheet
(including possible updated version) is available at www .epb .center.
No spreadsheet was produced on ISO 52017‑1, because this EPB standard (with reference hourly
thermal balance calculation procedures) is not directly used for calculations.
History of this Technical Report and the accompanying standards
The first series of standards on thermal and hygrothermal properties of building components and
elements were prepared by ISO Technical Committee 163 in the 1980s, as a result of growing global
concern on future fuel shortages and inadequate health and comfort levels in buildings. During the
following decades these first standards were revised and new standards were added, to cope with new
developments and additional needs. From the 1990s on, many of these standards were developed in
close collaboration with CEN (see further on).
[26]
As part of the Mandate 343 of the EC to CEN to support the EPBD (2003) , the series of standards
[25]
were scrutinized to see which changes would be needed for the purpose of supporting the EPBD .
This resulted in new versions of a number of standards, most of them published in 2007. The standards
[28]
were further revised in the 2010s as part of Mandate 480 of the EC to CEN , to support the EPBD
recast [ ].
More extensive background information and history of the set of EPB standards is given in the
[4]
Introduction to ISO/TR 52000-2 , the Technical Report accompanying the overarching EPB standard
[47],[48],[49]
and in recent ISO papers ( ).
Application area of ISO 52016-1:
ISO 52016-1 presents a coherent set of calculation methods at different levels of detail, for the (sensible)
energy needs for the space heating and cooling and (latent) energy needs (de‑)humidification of a
building and/or internal temperatures and heating and/or cooling loads.
The effect of specific system properties can also be taken into account, such as the maximum heating
or cooling power, and the impact of specific system control provisions. This leads to system-specific
energy loads and needs, in addition to the basic energy loads and needs.
ISO 52016‑1 contains both hourly and monthly calculation procedures. These are closely linked:
they use as much as possible the same input data and assumptions. And the hourly method produces
as additional output the key monthly quantities needed to generate parameters for the monthly
calculation method. This means that a number of (nationally) representative cases can be run with the
hourly method and from the key monthly quantities the monthly correlation factors can be derived
ISO 52016-1 has been developed for buildings that are, or are assumed to be, heated and/or cooled
for the thermal comfort of people, but can be used for other types of building or other types of use
(e.g. industrial, agricultural, swimming pool), as long as appropriate input data are chosen and the
impact of special physical conditions on the accuracy is taken into consideration.
NOTE 1 For instance, it can be used when a special model is needed but is missing.
viii © ISO 2017 – All rights reserved

Depending on the purpose of the calculation, it can be decided nationally to provide specific calculation
rules for thermal zones that are dominated by process heat (e.g. indoor swimming pool, computer/server
room or kitchen in a restaurant).
NOTE 2 For instance, in the case of a building energy certificate and/or building permit, e.g. by ignoring the
process heat or using default process heat for certain processes (e.g. shops: freezers, lighting in shop window).
Design heating and cooling load
Upon request of CEN/TC 156, the method to calculate the design heating and cooling and latent heat
load from prEN 16798-11:2015[ ], prepared by CEN/TC 156, has been integrated in ISO 52016‑1.
ISO 52016‑1 includes specification of the method and the boundary conditions for the calculation of
the design heating and cooling load, including latent load, as a basis for the dimensioning of equipment
on zone level and on central level for cooling and dehumidification. It specifies also the methods and
conditions for the calculation of the humidification load.
The method given for the design heat load is intended especially for the cases where the cooling load
calculation needs to be done (for instance when cooling is necessary) and/or an hourly calculation is
used for the energy needs calculation. The principle idea is that there is only one method needed for
load and energy calculations for heating and cooling in case of an hourly calculation interval.
A simplified steady state calculation method for the design heat load is given in EN 12831‑1[ ].
Link between the two standards, ISO 52017-1 and ISO 52016-1
In short, ISO 52017‑1 contains a generic (reference) hourly calculation method for building (zone). This
method is based on and replaces that in ISO 13791. This document contains no specific assumptions,
boundary conditions, specific simplifications or input data that are not needed to apply the generic
calculation method. Compared with ISO 13791, the heat flows describing the energy needs for heating
and cooling are added to increase the application range. This document does not include validation
cases (unlike ISO 13791). For validation, specific assumptions and input data would need to be given
that only apply to the validation cases. To keep a clear distinction between the generic method and a
specific application, verification and validation cases are adopted in ISO 52016‑1.
[5]
ISO 52016-1 replaces the information in ISO 13790:2008 . It contains a (new) hourly calculation
method and a monthly calculation method. The hourly calculation method is a specific application of
the generic method provided in ISO 52017‑1. ISO 52016‑1 further contains specific boundary conditions,
specific simplifications and input data for the application: calculation of energy needs for heating and
cooling. Amended simplifications and input data are provided for the application to calculate the design
heating and design cooling load and (e.g. summer) internal temperatures.
In this way the generic calculation method (ISO 52017‑1) is clearly separated from the specific
application with all specific assumptions, simplifications and specific input data (ISO 52016‑1). Due to
these changes, ISO 52016-1 together with ISO 52017-1 also replace ISO 13792.
The hourly method in ISO 52016‑1 produces as additional output the key parameters needed to generate
parameters for the monthly calculation method. This means that a number of (nationally) representative
cases can be run with the hourly method and from the output, the key monthly parameters for the
different cases, the monthly correlation factors can be derived.
See flowchart in Figure 1.
Figure 1 — Relationship between ISO 52016-1 and ISO 52017-1
Input-output relations between the two standards and other standards of the set of EPB
standards
As explained above, ISO 52017‑1 plays a role as a reference calculation method. For instance as reference
method for ISO 52016-1.
For the input‑output relations with the other EN and ISO standards in the set of EPB standards, only
ISO 52016-1 is relevant.
There are many inputs from and many interactions with many other EPB standards. More details are
given in the core of this document.
See flowchart in Figure 2.
x © ISO 2017 – All rights reserved

Figure 2 — Relationship between ISO 52016-1 and other EPB standards
NOTE 3 The list of referenced standards can be found in ISO 52016-1:2017, Table B.1.
TECHNICAL REPORT ISO/TR 52016-2:2017(E)
Energy performance of buildings — Energy needs for
heating and cooling, internal temperatures and sensible
and latent heat loads —
Part 2:
Explanation and justification of ISO 52016-1 and ISO
52017-1
1 Scope
This document contains information to support the correct understanding and use of ISO 52016-1 and
ISO 52017-1.
These documents give calculation methods for the assessment of:
— the (sensible and latent) energy load and need for heating and cooling, based on hourly calculations;
— the (sensible and latent) energy need for heating and cooling, based on monthly calculations
(ISO 52016-1);
— the internal temperature, based on hourly calculations; and
— the design (sensible and latent) heating and cooling load, based on hourly calculations.
This document does not contain any normative provisions.
NOTE A description of the rationale behind the reorganization of the cluster of strongly related and partly
overlapping ISO and CEN standards is given in Annex H.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
More information on the use of EPB module numbers, in all EPB standards, for normative references to
[4]
other EPB standards is given in ISO/TR 52000-2 .
ISO 52016-1:2017, Energy performance of buildings — Energy needs for heating and cooling, internal
temperatures and sensible and latent heat loads — Part 1: Calculation procedures
ISO 52017-1, Energy performance of buildings — Sensible and latent heat loads and internal temperatures
— Part 1: Generic calculation procedures
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 52016-1 and ISO 52017-1 apply.
This clause provides an explanation of some of the terms and definitions given in ISO 52016‑1:2017,
Clause 3 and ISO 52017-1: 2017, Clause 3.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at http:// www .iso .org/ obp
NOTE 1 Explanations on the terms and definitions that are copied from ISO 52000‑1 are given in ISO/TR
52000‑2. For instance on the difference between useful floor area and reference floor area. But also, more general
explanations, on the difference between a definition of a term (given in Clause 3) and a specification of a term
(procedure to assess the term).
NOTE 2 For terms that are sensitive to national or regional policy, building tradition or legal context, the EPB
standards contain a definition, but leave the specification to be provided at national or regional level, if possible
using Annex A (normative template) and Annex B (informative default choice).
NOTE 3 The term “load” is used in (sensible) heating or cooling load, latent heating or cooling load and
humidification or dehumidification moisture load. It is defined, for hourly calculations, as the hourly mean value
of the heat or mass flow rate supplied to or extracted from the internal environment to maintain the intended
space temperature or moisture conditions. The unit is Watt (J/s, for heat) or kg (for moisture; sometimes more
specifically called kg /s). See 6.5.14 for an explanation of the calculation of the moisture load versus latent
H2O
heat load for (de‑)humidification in the application of ISO 52016‑1. The load under design conditions, conditions
that are assumed for the design (sizing) of the system, is called “design load”.
NOTE 4 The term “power” is used for the heat flow rate that is available from the system to cover the load. If
the power is insufficient to cover the load, the system is called “undersized” and the operative temperature or air
moisture level in the internal environment exceeds the limit of the set-point in question.
NOTE 5 The term “need” is used for the heat to be delivered to, or extracted from the internal environment
to maintain the intended space temperature or moisture conditions during a given period of time. This period is
typically a month or a year. The unit is kWh (for heat) or kg (for moisture). See also 6.5.3 on the distinction
H2O
between “basic need” versus “system specific need” calculations.
4 Symbols, subscripts and abbreviations
4.1 Symbols
For the purposes of this document, the symbols given in ISO 52016-1 and ISO 52017-1 and the
following apply.
More information on key EPB symbols is given in ISO/TR 52000‑2.
Symbol Quantity Unit
ω ratio of the total solar radiation -
4.2 Subscripts
For the purposes of this document, the subscripts given in ISO 52016-1 and ISO 52017-1 and the
following apply.
2 © ISO 2017 – All rights reserved

More information on key EPB subscripts is given in ISO/TR 52000‑2.
Subscript Term Subscript Term
al air layer sw solar wall
hem hemispherical t transparent element
ref reflected te external thermal
transmittance
NOTE ISO 52016‑1 needs input data from many technology fields. In the exceptional cases that subscripts
in ISO 52016-1 are different from subscripts in other EPB standards that produce output needed as input to
ISO 52016-1, these differences are reported in a special column in the tables with the overview of input data in
6.3. This can occur when the source documents use subscripts that are crucial for that specific technology field,
but conflict with subscripts that are crucial for another specific technology field.
EXAMPLE Subscript g for glazing and for ground.
4.3 Abbreviations
For the purposes of this document, the abbreviations given in ISO 52016‑1 and ISO 52017‑1 apply.
More information on key EPB abbreviations is given in ISO/TR 52000‑2.
5 Brief description of the method(s) and routing
5.1 Output of the method
5.1.1 Reference hourly method in ISO 52017-1
ISO 52017‑1 is a generic reference hourly calculation method to calculate the thermal balance in
a building or building zone. The main output quantities are the indoor air and indoor mean radiant
temperature and (derived from these two) the operative temperature. The energy need for heating or
cooling can also be produced as output, at given heating and/or cooling set points for the operative
temperature. However, the actual conditions and temperature control specifications depend on the
application. ISO 52016‑1 contains such a specific hourly calculation method.
ISO 52017-1 also contains a moisture balance formula to calculate the moisture balance in a building
or building zone. The main output quantities are the moisture content of the internal air, the moisture
load and the latent energy load and need. Again in a generic way, because the actual moisture and latent
heat load depends on the specific application. This is covered in ISO 52016‑1.
5.1.2 Hourly method in ISO 52016-1
ISO 52016‑1 contains a specific hourly method to calculate the energy loads and needs for heating
and cooling and the hourly indoor temperature (air, mean radiant and operative). It also contains a
specific hourly method to calculate the moisture and latent energy loads and needs for humidification
and dehumidification and the hourly indoor air moisture content (humidity). The assumptions and
simplifications have been chosen in such a way that sufficient accuracy is obtained (e.g. in relation to
the reliability of input data and boundary conditions), with a minimum of required input data. The input
data to be gathered by the user of the calculation procedures is equal or equivalent to the input data for
the simplified monthly calculation method.
5.1.3 Monthly method in ISO 52016-1
ISO 52016‑1 contains also a specific monthly method to calculate the (monthly) energy needs for
heating and cooling, plus a specific simple monthly method to calculate the (monthly) energy needs for
(de‑)humidification.
5.
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