SIST-TP CEN ISO/TR 52010-2:2017

Energy performance of buildings - External climatic conditions - Part 2: Explanation and justification of ISO 52010-1 (ISO/TR 52010-2:2017)

This new technical report refers to standard EN 52010-1 on calculation of solar irradiance on an arbitrary plane based on measured hourly weather data. It contains information to support the correct understanding, use and national adaptation of that standard. This technical report does not contain any normative provision.

Energieeffizienz von Gebäuden - Äußere Klimabedingungen - Teil 2: Erläuterung und Begründung von ISO 52010-1 (ISO/TR 52010-2:2017)

Performance énergétique des bâtiments - Conditions climatiques extérieures - Partie 2: Explication et justification de l’ISO 52010-1 (ISO/TR 52010-2:2017)

N/A

Energetska učinkovitost stavb - Zunanje podnebne razmere - 2. del: Obrazložitev in utemeljitev ISO 52010-1 (ISO/TR 52010-2:2017)

To novo tehnično poročilo se sklicuje na standard EN 52010-1 v povezavi z izračunom sončnega obsevanja na poljubni ravnini, ki temelji na izmerjenih urnih vremenskih podatkih. Vsebuje informacije za podporo pravilnega razumevanja, uporabe in nacionalne prilagoditve tega standarda. To tehnično poročilo ne vsebuje nobenih normativnih določb.

General Information

• Status: Published
• Public Enquiry End Date: 09-Jan-2017
• Publication Date: 15-Aug-2017
• ICS: 27.015 - Energy efficiency. Energy conservation in general
• ICS: 91.120.10 - Thermal insulation of buildings
• Technical Committee: TOP - Thermal insulation
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Aug-2017
• Due Date: 06-Oct-2017
• Completion Date: 16-Aug-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: CEN ISO/TR 52010-2:2017 - Energy performance of buildings - External climatic conditions - Part 2: Explanation and justification of ISO 52010-1 (ISO/TR 52010-2:2017)

Standards Content (Sample)

SLOVENSKI STANDARD
SIST-TP CEN ISO/TR 52010-2:2017
01-september-2017
(QHUJHWVNDXþLQNRYLWRVWVWDYE=XQDQMHSRGQHEQHUD]PHUHGHO2EUD]ORåLWHY
LQXWHPHOMLWHY,62,6275
Energy performance of buildings - External climatic conditions - Part 2: Explanation and
justification of ISO 52010-1 (ISO/TR 52010-2:2017)
Energieeffizienz von Gebäuden - Äußere Klimabedingungen - Teil 2: Erläuterung und
Begründung von ISO 52010-1 (ISO/TR 52010-2:2017)
Performance énergétique des bâtiments - Conditions climatiques extérieures - Partie 2:
Explication et justification de l’ISO 52010-1 (ISO/TR 52010-2:2017)
Ta slovenski standard je istoveten z: CEN ISO/TR 52010-2:2017
ICS:
27.015 (QHUJLMVNDXþLQNRYLWRVW Energy efficiency. Energy
2KUDQMDQMHHQHUJLMHQD conservation in general
VSORãQR
91.120.10 Toplotna izolacija stavb Thermal insulation of
buildings
SIST-TP CEN ISO/TR 52010-2:2017 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST-TP CEN ISO/TR 52010-2:2017

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SIST-TP CEN ISO/TR 52010-2:2017


CEN ISO/TR 52010-2
TECHNICAL REPORT

RAPPORT TECHNIQUE

July 2017
TECHNISCHER BERICHT
ICS 91.120.10
English Version

Energy performance of buildings - External climatic
conditions - Part 2: Explanation and justification of ISO
52010-1 (ISO/TR 52010-2:2017)
Performance énergétique des bâtiments - Conditions Energieeffizienz von Gebäuden - Äußere
climatiques extérieures - Partie 2: Explication et Klimabedingungen - Teil 2: Erläuterung und
justification de l'ISO 52010-1 (ISO/TR 52010-2:2017) Begründung von ISO 52010-1 (ISO/TR 52010-2:2017)


This Technical Report was approved by CEN on 24 February 2017. It has been drawn up by the Technical Committee CEN/TC 89.

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 ISO/TR 52010-2:2017 E
worldwide for CEN national Members.

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SIST-TP CEN ISO/TR 52010-2:2017
CEN ISO/TR 52010-2:2017 (E)
Contents Page
European foreword . 3
2

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SIST-TP CEN ISO/TR 52010-2:2017
CEN ISO/TR 52010-2:2017 (E)
European foreword
This document (CEN ISO/TR 52010-2:2017) has been prepared by Technical Committee ISO/TC 163
"Thermal performance and energy use in the built environment" in collaboration with Technical
Committee CEN/TC 89 “Thermal performance of buildings and building components” the secretariat of
which is held by SIS.
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.
This document has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association.
This document is part of the set of standards and accompanying technical reports on the energy
performance of buildings and has been prepared under a mandate given to CEN by the European
Commission and the European Free Trade Association (Mandate M/480, see reference [EF3] below).
Directive 2010/31/EU recasting the Directive 2002/91/EC on energy performance of buildings (EPBD,
[EF4]) promotes the improvement of the energy performance of buildings within the European Union,
taking into account all types of energy uses (heating, lighting, cooling, air conditioning, ventilation) and
outdoor climatic and local conditions, as well as indoor climate requirements and cost effectiveness
(Article 1).
The directive requires Member States to adopt measures and tools to achieve the prudent and rational
use of energy resources. In order to achieve those goals, the EPBD requires increasing energy efficiency
and the enhanced use of renewable energies in both new and existing buildings. One tool for this is the
application by Member States of minimum requirements on the energy performance of new buildings
and for existing buildings that are subject to major renovation, as well as for minimum performance
requirements for the building envelope if energy-relevant parts are replaced or retrofitted. Other tools
are energy certification of buildings, inspection of boilers and air-conditioning systems.
The use of European standards increases the accessibility, transparency and objectivity of the energy
performance assessment in the Member States facilitating the comparison of best practices and
supporting the internal market for construction products. The use of EPB-standards for calculating
energy performance, as well as for energy performance certification and the inspection of heating
systems and boilers, ventilation and air-conditioning systems will reduce costs compared to developing
different standards at national level.
The first mandate to CEN to develop a set of CEN EPBD standards (M/343, [EF2]), to support the first
edition of the EPBD [EF1] resulted in the successful publication of all EPBD related CEN standards in
2007-2008.
The mandate M/480 was issued to review the mandate M/343, as the recast of the EPBD raised the
need to revisit the standards and reformulate and add standards so that they become on the one hand
unambiguous and compatible, and on the other hand provide a clear and explicit overview of the
choices, boundary conditions and input data that need to be defined at national or regional level. Such
national or regional choices remain necessary, due to differences in climate, culture & building
tradition, policy and legal frameworks. Consequently, the set of CEN-EPBD standards published in
2007-2008 had to be improved and expanded on the basis of the recast of the EPBD.
The EPB standards are flexible enough to allow for necessary national and regional differentiation and
facilitate Member States implementation and the setting of requirements by the Member States.
3

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SIST-TP CEN ISO/TR 52010-2:2017
CEN ISO/TR 52010-2:2017 (E)
Further target groups are users of the voluntary common European Union certification scheme for the
energy performance of non-residential buildings (EPBD art.11.9) and any other regional (e.g. Pan
European) parties wanting to motivate their assumptions by classifying the building energy
performance for a dedicated building stock.
References:
[EF1] EPBD, Directive 2002/91/EC of the European Parliament and of the Council of
16 December 2002 on the energy performance of buildings
[EF2] Mandate M/343, Mandate to CEN, CENELEC and ETSI for the elaboration and adoption of
standards for a methodology calculating the integrated energy performance of buildings and estimating
the environmental impact, in accordance with the terms set forth in Directive 2002/91/EC; 30 January
2004
[EF3] 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 of buildings (2010/31/EU) of 14th December 2010
[EF4] EPBD, Recast of the Directive on the energy performance of buildings (2010/31/EU) of 14th
December 2010
Endorsement notice
The text of ISO/TR 52010-2:2017 has been approved by CEN as CEN ISO/TR 52010-2:2017 without any
modification.

4

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SIST-TP CEN ISO/TR 52010-2:2017
TECHNICAL ISO/TR
REPORT 52010-2
First edition
2017-06
Energy performance of buildings -
External climatic conditions —
Part 2:
Explanation and justification of ISO
52010-1
Performance énergétique des bâtiments — Conditions climatiques
extérieures —
Partie 2: Explication et justification de l’ISO 52010-1
Reference number
ISO/TR 52010-2:2017(E)
©
ISO 2017

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SIST-TP CEN ISO/TR 52010-2:2017
ISO/TR 52010-2:2017(E)

COPYRIGHT PROTECTED DOCUMENT
© 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

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SIST-TP CEN ISO/TR 52010-2:2017
ISO/TR 52010-2:2017(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and subscripts . 1
5 Description of the methods . 1
5.1 Output of the method . 1
5.2 General description of the method . 2
5.2.1 Calculation of the distribution of solar irradiance on a non-horizontal plane . 2
5.2.2 Calculation of solar shading by distant objects . 3
6 Calculation method . 4
6.1 Output data . 4
6.2 Calculation time intervals . 4
6.3 Input data . 4
6.4 Calculation procedure . 4
6.4.1 Calculation of the sun path . . 4
6.4.2 Split between direct and diffuse solar irradiance . 4
6.4.3 Solar reflectivity of the ground . 4
6.4.4 Calculation of the total solar irradiance at given orientation and tilt angle . 4
6.4.5 Calculation of shading by external objects . 5
6.4.6 Calculation of illuminance . 5
7 Quality control . 5
8 Compliance check . 5
9 Directional (spatial) distribution of hourly solar irradiation or illumination (not
covered in ISO 52010-1) . 5
9.1 General . 5
9.2 Tregenza elements . 6
9.3 Allocation of the radiation in each element . 6
9.4 Plane at certain orientation and tilt . 7
9.5 References . 9
10 Worked out examples . 9
10.1 Method calculation of the total solar irradiation at given orientation and tilt angle . 9
10.2 Calculation of shading by external objects . 9
11 Validation . 9
12 Information on the accompanying spreadsheet .12
Annex A (informative) Input and method selection data sheet — Template.13
Annex B (informative) Input and method selection data sheet — Default choices .14
Annex C (informative) Calculation examples on the solar irradiation at given orientation
and tilt angle .15
Annex D (informative) Calculation examples on the effect of solar shading .20
Bibliography .23
© ISO 2017 – All rights reserved iii

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SIST-TP CEN ISO/TR 52010-2:2017
ISO/TR 52010-2:2017(E)

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.
ISO/TR 52010-2 was prepared by ISO technical committee ISO/TC 163, Thermal performance and
energy use in the built environment, Subcommittee SC 2, Calculation methods, in collaboration 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 52010 series can be found on the ISO website.
iv © ISO 2017 – All rights reserved

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SIST-TP CEN ISO/TR 52010-2:2017
ISO/TR 52010-2:2017(E)

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 (calculation) 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 has been 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.
[10]
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.
© ISO 2017 – All rights reserved v

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SIST-TP CEN ISO/TR 52010-2:2017
ISO/TR 52010-2:2017(E)

This document
This document accompanies ISO 52010-1, which forms part of the set of EPB standards.
The role and the positioning of the accompanied standard in the set of EPB standards is defined in the
Introduction to ISO 52010-1.
[27] [28]
Brief articles on the subject can be found in and .
ISO 52010-1 provides the common standard climatic data to be used as input by all EPB standards. It
builds on ISO 15927-1, ISO 15927-2 and ISO 15927-4 and completes a missing link: the calculation of the
distribution of solar irradiation and illuminance on a non-horizontal plane based on measured hourly
solar radiation data on a horizontal surface; with or without taking into account solar shading.
Typical inputs for ISO 52010-1 are the hourly values for diffuse horizontal and direct beam solar irradiation.
However, these quantities are not necessarily directly measured. In many cases, only the global horizontal
irradiation is available as measured parameter, and the two components need to be calculated with a
model. There are alternative models provided, open for choice at national or regional level.
For ground reflectivity often a constant value of, e.g., 0,2 is used. However, the value depends greatly
on the surface conditions, and the influence on the irradiation is not negligible. Therefore, the option of
providing hourly values is included. This may be especially of importance for mountain regions or for
high latitudes.
For the solar shading calculation, the height and distance of each shading object are given per sector of
the horizon (360 degrees). The subdivision into sectors (small or large) is open for national or regional
[5]
choice. The same solar shading calculation procedure is adopted in ISO 52016-1 for the calculation of
the building energy needs and loads. This is especially important because if there are different shading
objects in the same sector, it will not be correct to calculate the effects separately in different standards.
It is up to national or regional choice to decide about the details of the solar shading calculations.
Accompanying spreadsheet
In line with the common template for all EPB standards, a spreadsheet has been prepared for
demonstration and validation. This spreadsheet shows an overview of all input variables, the (step by
step) hourly calculation procedures and an overview of all output variables.
This accompanying calculation spreadsheet (July 2016) provides:
— full year of hourly calculations of solar irradiance (split in components) on plane with any azimuth
and tilt angle;
— validated against BESTEST cases;
— hourly calculations of solar shading by multiple shading objects along the skyline. These calculations
[5]
also cover the calculation procedures for overhangs from ISO 52016-1 .
This spreadsheet (including possible updated version) is available at www .epb .center.
vi © ISO 2017 – All rights reserved

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SIST-TP CEN ISO/TR 52010-2:2017
TECHNICAL REPORT ISO/TR 52010-2:2017(E)
Energy performance of buildings - External climatic
conditions —
Part 2:
Explanation and justification of ISO 52010-1
1 Scope
This document contains information to support the correct understanding and use of ISO 52010-1.
This document does not contain any normative provision.
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.
ISO/ 52010-1:2010, Energy performance of buildings — External climatic conditions — Part 1: Conversion
of climatic data for energy calculations
NOTE More information on the use of EPB module numbers, in all EPB standards, for normative references
[4]
to other EPB standards is given in ISO/TR 52000-2 .
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 52010-1, apply.
[4]
More information on some key EPB terms and definitions is given in ISO/TR 52000-2 .
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
4 Symbols and subscripts
For the purposes of this document, the symbols and subscripts given in ISO 52010-1, apply.
[4]
More information on key EPB symbols and subscripts is given in ISO/TR 52000-2 .
5 Description of the methods
5.1 Output of the method
Beside solar radiation data, ISO 52010-1 also contains data regarding
— air temperature;
— atmospheric humidity;
© ISO 2017 – All rights reserved 1

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SIST-TP CEN ISO/TR 52010-2:2017
ISO/TR 52010-2:2017(E)

— wind speed;
— wind direction;
— longwave radiation.
The definitions and data are obtained from the ISO 15927 series regarding hygrothermal performance
[7] [8]
of buildings ( , ).
The reason for passing these data via this standard is to have one single and consistent source for all
EPB standards and to enable any treatment if needed for specific application. The above mentioned
climatic data are not processed in this standard.
5.2 General description of the method
5.2.1 Calculation of the distribution of solar irradiance on a non-horizontal plane
[20]
It is (Torres 2006 ,) of paramount importance for HVAC (heating, ventilating and air conditioning)
and photovoltaic systems designers to have suitable models requiring usually available data in order to
calculate the irradiance on the plane where conversion systems are located.
From all the models developed to fulfil this objective, the one of conversion or translation proposed
by Perez et al. (1986) has been widely used, as it considers all sky conditions ranging from completely
[17]
covered to clear sky (Pohlen et al., 1996 ).
Essentially, the model is composed of three different components:
1) a geometric representation of the sky dome,
2) a parametric representation of the insolation conditions, and
[15]
3) a statistic component linking both components mentioned before (Perez et al., 1987 ).
It is a model of anisotropic sky, where the sky dome is geometrically divided into three areas, each of
them showing a constant radiance, different from the other two (see Figure 1).
These three areas are:
— isotropic diffuse (for the sky hemisphere);
— circumsolar radiation;
— horizon brightness.
2 © IS
...

SLOVENSKI STANDARD
kSIST-TP FprCEN ISO/TR 52010-2:2017
01-januar-2017
(QHUJHWVNDXþLQNRYLWRVWVWDYE=XQDQMHSRGQHEQHUD]PHUHGHO2EUD]ORåLWHY
LQXWHPHOMLWHY,62,62'75
Energy performance of buildings - External climatic conditions - Part 2: Explanation and
justification of ISO 52010-1 (ISO/DTR 52010-2:2016)
Energieeffizienz von Gebäuden - Äußere Klimabedingungen - Teil 2: Erläuterung und
Begründung von ISO 52010-1 (ISO/DTR 52010-2:2016)
Performance énergétique des bâtiments - Conditions climatiques extérieures - Partie 2:
Explication et justification de l’ISO 52010-1 (ISO/DTR 52010-2:2016)
Ta slovenski standard je istoveten z: FprCEN ISO/TR 52010-2
ICS:
27.015 (QHUJLMVNDXþLQNRYLWRVW Energy efficiency. Energy
2KUDQMDQMHHQHUJLMHQD conservation in general
VSORãQR
91.120.10 Toplotna izolacija stavb Thermal insulation of
buildings
kSIST-TP FprCEN ISO/TR 52010-2:2017 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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kSIST-TP FprCEN ISO/TR 52010-2:2017

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kSIST-TP FprCEN ISO/TR 52010-2:2017
TECHNICAL ISO/TR
REPORT 52010-2
First edition
Energy performance of buildings -
External climatic conditions —
Part 2:
Explanation and justification of ISO
52010-1
Performance énergétique des bâtiments — Conditions climatiques
extérieures —
Partie 2: Explication et justification de l’ISO 52010-1
PROOF/ÉPREUVE
Reference number
ISO/TR 52010-2:2016(E)
©
ISO 2016

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kSIST-TP FprCEN ISO/TR 52010-2:2017
ISO/TR 52010-2:2016(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2016, 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 2016 – All rights reserved

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kSIST-TP FprCEN ISO/TR 52010-2:2017
ISO/TR 52010-2:2016(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and subscripts . 1
5 Description of the methods . 1
5.1 Output of the method . 1
5.2 General description of the method . 2
5.2.1 Calculation of the distribution of solar irradiance on a non-horizontal plane . 2
5.2.2 Calculation of solar shading by distant objects . 3
6 Calculation method . 4
6.1 Output data . 4
6.2 Calculation time intervals . 4
6.3 Input data . 4
6.4 Calculation procedure . 4
6.4.1 Calculation of the sun path . . 4
6.4.2 Split between direct and diffuse solar irradiance . 4
6.4.3 Solar reflectivity of the ground . 4
6.4.4 Calculation of the total solar irradiance at given orientation and tilt angle . 4
6.4.5 Calculation of shading by external objects . 5
6.4.6 Calculation of illuminance . 5
7 Quality control . 5
8 Compliance check . 5
9 Directional (spatial) distribution of hourly solar irradiation or illumination (not
covered in ISO 52010-1) . 5
9.1 General . 5
9.2 Tregenza elements . 6
9.3 Allocation of the radiation in each element . 6
9.4 Plane at certain orientation and tilt . 7
9.5 References . 9
10 Worked out examples . 9
10.1 Method calculation of the total solar irradiation at given orientation and tilt angle . 9
10.2 Calculation of shading by external objects . 9
11 Validation . 9
12 Information on the accompanying spreadsheet .12
Annex A (informative) Input and method selection data sheet — Template.13
Annex B (informative) Input and method selection data sheet — Default choices .14
Annex C (informative) Calculation examples on the solar irradiation at given orientation
and tilt angle .15
Annex D (informative) Calculation examples on the effect of solar shading .20
Bibliography .23
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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 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: www.iso.org/iso/foreword.html.
The committee responsible for this document is ISO/TC 163, Thermal performance and energy use in the
built environment, Subcommittee SC 2, Calculation methods.
A list of all parts in the ISO 52010- series, published under the general title Energy performance of
buildings — External climatic conditions, can be found on the ISO website.
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Introduction
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:
[2]
CEN/TS 16628 ;
b) a document with detailed technical rules to be followed in drafting EPB-standards;
[3]
CEN/TS 16629 ;
c) 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 (calculation) 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
1)
[4]
overarching EPB standard, ISO 52000-1 .
One of the main purposes of the revision of the EPB standards has been 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
[3]
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.
[8]
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.
1) To be published.
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This technical report
[1]
This technical report accompanies ISO 52010-1, which forms part of the set of EPB standards.
The role and the positioning of the accompanied standard in the set of EPB standards is defined in the
Introduction to ISO 52010-1. More information on the use of EPB module numbers, in all EPB standards,
[5]
for normative references to other EPB standards is given in ISO/TR 52000-2 .
[28]
A brief article on the subject can be found in .
ISO 52010-1 provides the common standard climatic data to be used as input by all EPB standards. It
builds on ISO 15927-1, ISO 15927-2 and ISO 15927-4 and completes a missing link: the calculation of the
distribution of solar irradiation and illuminance on a non-horizontal plane based on measured hourly
solar radiation data on a horizontal surface; with or without taking into account solar shading.
Typical inputs for ISO 52010-1 are the hourly values for diffuse horizontal and direct beam solar irradiation.
However, these quantities are not necessarily directly measured. In many cases, only the global horizontal
irradiation is available as measured parameter, and the two components need to be calculated with a
model. There are alternative models provided, open for choice at national or regional level.
For ground reflectivity often a constant value of, e.g., 0,2 is used. However, the value depends greatly
on the surface conditions, and the influence on the irradiation is not negligible. Therefore, the option of
providing hourly values is included. This may be especially of importance for mountain regions or for
high latitudes.
For the solar shading calculation, the height and distance of each shading object are given per sector
of the horizon (360 degrees). The subdivision into sectors (small or large) is open for national or
2)
[6]
regional choice. The same solar shading calculation procedure is adopted in ISO 52016-1 , for the
calculation of the building energy needs and loads. This is especially important because if there are
different shading objects in the same sector, it will not be correct to calculate the effects separately
in different standards. It is up to national or regional choice to decide about the details of the solar
shading calculations.
Accompanying spreadsheet
In line with the common template for all EPB standards, a spreadsheet has been prepared for
demonstration and validation. This spreadsheet shows an overview of all input variables, the (step by
step) hourly calculation procedures and an overview of all output variables.
This accompanying calculation spreadsheet (July 2016) provides:
— full year of hourly calculations of solar irradiance (split in components) on plane with any azimuth
and tilt angle;
— validated against BESTEST cases;
— hourly calculations of solar shading by multiple shading objects along the skyline. These calculations
[6]
also cover the calculation procedures for overhangs from ISO 52016-1 .
2) To be published.
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kSIST-TP FprCEN ISO/TR 52010-2:2017
TECHNICAL REPORT ISO/TR 52010-2:2016(E)
Energy performance of buildings - External climatic
conditions —
Part 2:
Explanation and justification of ISO 52010-1
1 Scope
This document contains information to support the correct understanding and use of ISO 52010-1.
This document does not contain any normative provision.
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.
There are no normative references in this document.
3 Terms and definitions
[1]
For the purposes of this document, the terms and definitions given in ISO 52010-1, apply.
[5]
More information on some key EPB terms and definitions is given in ISO/TR 52000-2.
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
4 Symbols and subscripts
[1]
For the purposes of this document, the symbols and subscripts given in ISO 52010-1, apply.
[5]
More information on key EPB symbols and subscripts is given in ISO/TR 52000-2 .
5 Description of the methods
5.1 Output of the method
Beside solar radiation data, ISO 52010-1 also contains data regarding
— air temperature;
— atmospheric humidity;
— wind speed;
— wind direction;
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— longwave radiation.
The definitions and data are obtained from the ISO 15927 series regarding hygrothermal performance
[8] [9]
of buildings ( , ).
The reason for passing these data via this standard is to have one single and consistent source for all
EPB standards and to enable any treatment if needed for specific application. The above mentioned
climatic data are not processed in this standard.
5.2 General description of the method
5.2.1 Calculation of the distribution of solar irradiance on a non-horizontal plane
[21]
It is (Torres 2006 ,) of paramount importance for HVAC (heating, ventilating and air conditioning)
and photovoltaic systems designers to have suitable models requiring usually available data in order to
calculate the irradiance on the plane where conversion systems are located.
From all the models developed to fulfil this objective, the one of conversion or translation proposed
by Perez et al. (1986) has been widely used, as it considers all sky conditions ranging from completely
[18]
covered to clear sky (Pohlen et al., 1996 ).
Essentially, the model is composed of three different components:
1) a geometric representation of the sky dome,
2) a parametric representation of the insolation conditions, and
[16]
3) a statistic component linking both components mentioned before (Perez et al., 1987 ).
It is a model of anisotropic sky, where the sky dome is geometrically divided into three areas, each of
them showing a constant radiance, different from the other two (see Figure 1).
These three areas are:
— isotropic diffuse (for the sky hemisphere);
— circumsolar radiation;
— horizon brightness.
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Key
a circumsolar radiation
b sunbeam
c atmosphere
d horizon brightening
Figure 1 — Sky hemisphere areas according to Perez
And to be added to these three:
— Isotropic ground reflected radiation.
This anisotropic diffuse (sky) radiation for the plane uses as input hourly values the diffuse horizontal
and direct beam solar radiation. Other inputs to the model include the sun’s incident angle to the plane,
the plane tilt angle from the horizontal, and the sun’s zenith angle.
The model is named after Mr Perez. Several improvements were made in the course of time, see the list
of references in the bibliography.
The calculation procedure described in ISO 52010-1 is based on the “simplified Perez model” proposed
in the early 90s.
5.2.2 Calculation of solar shading by distant objects
Objects in the environment may block part of the solar irradiation on a plane (e.g., hills, trees, other
buildings).
The same or other objects may also reflect solar radiation and consequently lead to a higher irradiation.
NOTE For example, on the northern hemisphere, a highly reflecting surface (e.g., glazed adjacent building) in
front of the North facing façade of the assessed building.
In order to avoid that for those objects, specific solar reflectivity data are gathered. It is, as simplification,
assumed that:
a) The direct radiation (including circumsolar irradiation) is partially blocked, if the object is in the
path between sun and plane;
b) the diffuse irradiation (including irradiation from ground reflectance) remains unaffected.
This is physically equal to the situation where the radiation reflected (and/or transmitted) by the
objects in the environment is equal to the diffuse radiation blocked by these objects.
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Examples of the calculation are presented in Clause 10.
An alternative method is to take diffuse shading into account. In order to do this sky view factors are
calculated. This can be simplified by dividing the skyline in different segments and calculate the sky
view factors for each segment separately assuming an equal skyline height over the segment. This
[6]
approach is presented as an option in ISO 52016-1, with informative calculation procedures provided
[7]
in ISO/TR 52016-2 .
6 Calculation method
6.1 Output data
No special limitations on the output are applicable.
6.2 Calculation time intervals
The conversion from measured solar irradiance on horizontal surface to an arbitrary inclined surface
is instantaneous. Most measured data are available integrated over a period of an hour. To convert
this data special care is taken for the calculation of the solar position used for the conversion. The
position is determined in the middle of the measured period. In the determination of the hour angle
(ISO 52010-1:—, 6.4.1.5) this is taken into account.
6.3 Input data
No additional information beyond the accompanied standard.
6.4 Calculation procedure
6.4.1 Calculation of the sun path
See explanation in 6.2 on the sensitivity of the calculation results for the position of the sun. See also
ISO 52010-1:—, Clause 7.
6.4.2 Split between direct and diffuse solar irradiance
A number of models, based on statistical analysis of measured data, have been developed in different
climates to enable global solar irradiance to be split into the direct and diffuse parts, if such split is not
directly available from measured data.
The European Solar Radiation Atlas (3rd edition) contains a complete description of methods for
[21]
analysing solar data. The European Solar Radiation Atlas (4th edition of 2000, ESRA 4 ) contains on a
CD-Rom not only a database but also 10 algorithmic chains for deriving modified quantities.
On Method 1 in ISO 52010-1:—, 6.4.2.1:
The global irradiance, measured on a horizontal plane, is split into the approximate direct and diffuse
[22]
fractions by calculating the diffuse fraction according to the statistical results in Erbs .
6.4.3 Solar reflectivity of the ground
No additional information beyond the accompanied standard.
6.4.4 Calculation of the total solar irradiance at given orientation and tilt angle
See also the general brief explanation given in 5.2.1.
[22]
The method in ISO 52010-1 is based on the Perez 1990 method as described in Duffie and Beckman .
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There are two minor points of discussion.
1) In different literature different values for the values for clearness parameter and brightness
coefficient are used (ISO 15010-1:—, Table 10). The values used in ISO 52010-1 are based on the
publication in Duffie and Beckman. The values found in other literature do not differ significantly.
2) In different literature several definitions of the a and b factors (ISO 52010-1:—, 6.4.2) are given.
The values are used to determine the circumsolar component. The definitions used are based on
the publication in Duffie and Beckman.
6.4.5 Calculation of shading by external objects
See the general brief explanation given in 5.2.2.
6.4.6 Calculation of illuminance
See the more detailed method described in Clause 9.
7 Quality control
A number of checks can be made to increase confidence in correct implementation of the calculation
procedures of the standard. These are presented in ISO 52010-1:—, Clause 7.
Annex C shows examples of such checks; see in particular Table C.5 and Figure C.2.
8 Compliance check
No additional information beyond the accompanied standard.
9 Directional (spatial) distribution of hourly solar irradiation or illumination
(not covered in ISO 52010-1)
9.1 General
The distribution of irradiation on a non-horizontal plane calculated hourly with the method described
in the standard can be used to provide a more detailed spatial distribution.
Such detailed spatial distribution can be used for situations where the directional distribution of the
[25]
solar radiation or luminance is relevant, for instance in case of non-isotropic window elements
(e.g., Venetian blinds), (other) daylight elements with Bi-directional Transmission (and Reflection)
Distribution Functions (BTDF), for instance for the assessment of task illuminance levels and/or to
assess the luminance distribution in a room, discomfort glare or other visual comfort related parameters
in a room (with or without additional artificial lighting).
The method used in the standard ISO 52010-1 (based on Perez) yields the following components:
— beam radiation (direct from the sun),
— circumsolar radiation from the immediate vicinity of the sun,
— isotropic diffuse radiation,
— near-horizon radiation,
— ground reflected radiation (assumed to be homogeneously diffuse).
The conversion from radiation to luminance can be done on the basis of the assumption of a constant
luminous efficacy (lm/W); see, e.g., ISO 52010-1:—, 6.4.6.
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9.2 Tregenza elements
[24]
It was Tregenza who suggested the distribution of the sky into 145 elements, to obtain the spatial
distribution of the (solar radiation and) luminance over the hemisphere seen by an object (see Figure 2).
Seen from a horizontal position, the 145 Tregenza
...