SIST EN ISO 22975-3:2014
(Main)Solar energy - Collector components and materials - Part 3: Absorber surface durability (ISO 22975-3:2014)
Solar energy - Collector components and materials - Part 3: Absorber surface durability (ISO 22975-3:2014)
EN ISO 22975-3 is applicable to the determination of the long term behaviour and service life of selective solar absorbers for use in vented flat plate solar collectors working under conditions corresponding to that in a typical solar domestic hot water system or combisystem. This part of ISO 22975 specifies a failure criterion of a solar absorber based on changes in optical performance of the absorber. The optical properties of interest are solar absorptance and thermal emittance. This part of ISO 22975 specifies durability testing procedures focused on resistance to high temperatures and condensation of water on the absorber surface as well as high humidity in the presence of sulfur dioxide.
Thermische Solaranlagen und ihre Bauteile - Kollektoren - Teil 3: Qualifizierung der Beständigkeit von Solarabsorberflächen (ISO 22975-3:2014)
Diese Europäische Norm gilt für die Bestimmung des Langzeit-Verhaltens und der Lebensdauer von selek-tiven Solarabsorbern für Sonnenkollektoren, die unter typischen Bedingungen für Warmwasseranlagen in Wohn¬gebäuden arbeiten.
Diese Europäische Norm legt ein Ausfallkriterium für Solarabsorber auf Grundlage der Veränderungen in dessen optischer Leistung fest. Die betrachteten optischen Eigenschaften sind der solare Absorptions¬grad und der Wärmeemissionsgrad.
Diese Europäische Norm legt Verfahren zur Beständigkeitsprüfung mit Schwerpunkt auf Hoch¬temperatur-beständigkeit, Wasserkondensation auf der Absorberfläche und Luft mit hoher Feuchte und Schwefel-dioxidanteil fest.
Energie solaire - Composants et matériaux du collecteur - Partie 3: Durabilité de la surface de l'absorbeur (ISO 22975-3:2014)
L'ISO 22975-3:2014 est applicable à la détermination du comportement à long terme et de la durée de vie en service des absorbeurs solaires sélectifs destinés à être utilisés dans des capteurs solaires plan aéré fonctionnant dans des conditions correspondant à celles de systèmes solaires de types de production d'eau chaude sanitaire ou de système combiné.
L'ISO 22975-3:2014 spécifie un critère de défaillance d'un absorbeur solaire basé sur des modifications des performances optiques de l'absorbeur. Les propriétés optiques concernées sont l'absorptance solaire et l'émissivité thermique.
L'ISO 22975-3:2014 spécifie des modes opératoires d'essai de durabilité focalisés sur la résistance aux températures élevées et de la condensation d'eau sur la surface d'absorbeur autant que la résistance à une forte humidité en présence de dioxyde de soufre.
Sončna energija - Sestavni deli in materiali sprejemnikov sončne energije - 3. del: Obstojnost površine absorberja (ISO 22975-3:2014)
Standard EN ISO 22975-3 se uporablja za ugotavljanje dolgoročnega obnašanja in dobe trajanja selektivnih sončnih absorberjev za uporabo v prezračevanih ploščatih sprejemnikih sončne energije, ki delujejo pod pogoji, ki ustrezajo pogojem v običajnem sončnem toplovodnem sistemu v gospodinjstvu ali kombiniranem sistemu. Ta del standarda EN ISO 22975 določa merila za odpoved sončnega absorberja, ki temelji na spremembah v optični zmogljivosti absorberja. Preučevane optične lastnosti so sončna absorptanca in toplotna emisivnost. Ta del standarda ISO 22975 določa postopke preskušanja obstojnosti, osredotočene na odpornost na visoke temperature in kondenzacijo vode na površini absorberja ter tudi visoko vlažnost v prisotnosti žveplovega dioksida.
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 22975-3:2014
01-september-2014
6RQþQDHQHUJLMD6HVWDYQLGHOLLQPDWHULDOLVSUHMHPQLNRYVRQþQHHQHUJLMHGHO
2EVWRMQRVWSRYUãLQHDEVRUEHUMD ,62
Solar energy - Collector components and materials - Part 3: Absorber surface durability
(ISO 22975-3:2014)
Thermische Solaranlagen und ihre Bauteile - Kollektoren - Teil 3: Qualifizierung der
Beständigkeit von Solarabsorberflächen (ISO 22975-3:2014)
Energie solaire - Composants et matériaux du collecteur - Partie 3: Durabilité de la
surface de l'absorbeur (ISO 22975-3:2014)
Ta slovenski standard je istoveten z: EN ISO 22975-3:2014
ICS:
27.160 6RQþQDHQHUJLMD Solar energy engineering
SIST EN ISO 22975-3:2014 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 22975-3:2014
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SIST EN ISO 22975-3:2014
EUROPEAN STANDARD
EN ISO 22975-3
NORME EUROPÉENNE
EUROPÄISCHE NORM
July 2014
ICS 27.160
English Version
Solar energy - Collector components and materials - Part 3:
Absorber surface durability (ISO 22975-3:2014)
Energie solaire - Composants et matériaux du collecteur - Thermische Solaranlagen und ihre Bauteile - Kollektoren -
Partie 3: Durabilité de la surface de l'absorbeur (ISO 22975- Teil 3: Qualifizierung der Beständigkeit von
3:2014) Solarabsorberflächen (ISO 22975-3:2014)
This European Standard was approved by CEN on 7 May 2014.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same
status as the official versions.
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,
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Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2014 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 22975-3:2014 E
worldwide for CEN national Members.
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SIST EN ISO 22975-3:2014
EN ISO 22975-3:2014 (E)
ContentsPage
Foreword .3
2
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SIST EN ISO 22975-3:2014
EN ISO 22975-3:2014 (E)
Foreword
The text of ISO 22975-3:2014 has been prepared by Technical Committee ISO/TC 180 “Solar energy” of the
International Organization for Standardization (ISO) and has been taken over as EN ISO 22975-3:2014 by
Technical Committee CEN/TC 312 “Thermal solar systems and components” the secretariat of which is held
by ELOT.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by January 2015, and conflicting national standards shall be withdrawn at
the latest by January 2015.
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.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
Endorsement notice
The text of ISO 22975-3:2014 has been approved by CEN as EN ISO 22975-3:2014 without any modification.
3
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SIST EN ISO 22975-3:2014
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SIST EN ISO 22975-3:2014
INTERNATIONAL ISO
STANDARD 22975-3
First edition
2014-07-01
Solar energy — Collector components
and materials —
Part 3:
Absorber surface durability
Energie solaire — Composants et matériaux du collecteur —
Partie 3: Durabilité de la surface de l’absorbeur
Reference number
ISO 22975-3:2014(E)
©
ISO 2014
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SIST EN ISO 22975-3:2014
ISO 22975-3:2014(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2014
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
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Web www.iso.org
Published in Switzerland
ii © ISO 2014 – All rights reserved
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SIST EN ISO 22975-3:2014
ISO 22975-3:2014(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Requirements and classification . 2
5 Test methods for assessing material properties as measure of absorber performance .3
5.1 Sampling and preparation of test specimens . 3
5.2 Sample conditioning. 4
5.3 Solar absorptance . 4
5.4 Thermal emittance . 4
5.5 Adhesion . 4
6 Tests for assessing the thermal stability of absorber surfaces . 4
6.1 Principle . 4
6.2 Apparatus . 5
6.3 Procedure for execution of high temperature tests. 6
6.4 Qualification procedure . 7
7 Tests for determining the resistance to condensed water of absorber surfaces .7
7.1 Principle . 7
7.2 Apparatus . 8
7.3 Procedure for execution of constant condensation tests . 9
7.4 Qualification procedure .10
8 Test for determining absorber surface corrosion resistance to high humidity air
containing sulfur dioxide.10
8.1 Principle .10
8.2 Apparatus .11
8.3 Reference test specimen .12
8.4 Procedure for execution of corrosion test in high humidity air containing sulfur dioxide 12
8.5 Determination of shortest acceptable failure times in test by use of reference
test specimens .13
8.6 Qualification procedure .13
9 Test report .14
Annex A (normative) Procedure for determination of solar absorption and thermal emittance of
absorber surfaces .15
Annex B (normative) Temperature and failure time characteristics in assessment of thermal
stability of absorber surface .19
Annex C (normative) Temperature/condensation and failure time characteristics together
with qualification scheme in assessment of resistance to condensed water of
absorber surface .25
Annex D (informative) Suitable designs for test apparatus to be used in the qualification testing of
solar absorber surfaces .28
Bibliography .30
© ISO 2014 – All rights reserved iii
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SIST EN ISO 22975-3:2014
ISO 22975-3:2014(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 meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 180, Solar energy.
ISO 22975 consists of the following parts, under the general title Solar energy — Collector components
and materials:
— Part 3: Absorber surface durability
The following parts are under preparation:
— Part 1: Evacuated tubes – Durability and performance
— Part 2: Heat-pipe for solar thermal application — Durability and performance
iv © ISO 2014 – All rights reserved
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SIST EN ISO 22975-3:2014
ISO 22975-3:2014(E)
Introduction
To effectively select, use and maintain a material in a given application, its degradation under service
conditions must be predicted prior to use. Preferably, the durability of the material should be expressed
quantitatively in terms of an expected service life. Durability in this case is the ability of a material
to withstand deterioration caused by external factors in the environment, which may influence the
performance of the material under service conditions. Service life is defined as the period of time after
installation during which specific material properties important for the performance of the material
meet or exceed minimum acceptable values.
The service life of a material is, thus, not solely dependent on its physical and chemical properties, but
also on its performance requirement in the application considered, and on the external environmental
factors, which influence performance under service conditions. In design work, the important question
is if a specific material can be expected to have a service life longer than a certain value, the so-called
design service life; the latter dictated by life cost considerations taking into account the total system.
Service life assessment may be based on feed-back data from practice or on results from so-called
qualification or acceptance durability tests.
The present recommended qualification procedure for solar absorber surface durability is based on the
conduct of a series of short-term durability tests. During a test the optical performance of the absorber
surface tested is determined by measuring its solar absorptance and thermal emittance. From the loss
in optical performance of the absorber surface, its failure time in the test performed is assessed and
compared with the shortest acceptable failure time set by the design service life of the absorber. Design
service life, performance requirement defining failure time in terms of loss in optical performance,
classification of type and levels of environmental stress are set under the assumption, that the absorber
surface tested will be installed in a vented flat plate solar collector for use in domestic hot water systems
and combisystems or under similar operating conditions.
The recommended qualification procedure may favourably be used in the development and validation
of new kinds of absorber surfaces. From the results of tests, it can be concluded whether it is likely that
an absorber surface tested may meet the requirement for an acceptable service life also in practice.
The recommended durability testing procedure has proved to give results in fairly good agreement,
both qualitatively and quantitatively, with what has actually been observed on absorber surfaces tested
for longer time periods in solar collectors working under conditions corresponding to that in a typical
domestic solar hot water system or combisystem. Nevertheless, if the tested absorber could not be
qualified by present procedure, a more comprehensive investigation on durability is recommended and
can still lead to a qualification.
The present procedure consists of three parts to test the absorber with respect to its stability against
high temperature, against high humidity and condensation and against corrosion caused by atmospheric
sulfur dioxide. The three parts are independent and can be assessed individually.
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SIST EN ISO 22975-3:2014
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SIST EN ISO 22975-3:2014
INTERNATIONAL STANDARD ISO 22975-3:2014(E)
Solar energy — Collector components and materials —
Part 3:
Absorber surface durability
1 Scope
This part of ISO 22975 is applicable to the determination of the long term behaviour and service life
of selective solar absorbers for use in vented flat plate solar collectors working under conditions
corresponding to that in a typical solar domestic hot water system or combisystem.
This part of ISO 22975 specifies a failure criterion of a solar absorber based on changes in optical
performance of the absorber. The optical properties of interest are solar absorptance and thermal
emittance.
This part of ISO 22975 specifies durability testing procedures focused on resistance to high temperatures
and condensation of water on the absorber surface as well as high humidity in the presence of sulfur
dioxide.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 4624, Paints and varnishes — Pull-off test for adhesion
ISO 8407, Corrosion of metals and alloys — Removal of corrosion products from corrosion test specimens
ISO 9050, Glass in building — Determination of light transmittance, solar direct transmittance, total solar
energy transmittance, ultraviolet transmittance and related glazing factors
ISO 10062, Corrosion tests in artificial atmosphere at very low concentrations of polluting gas(es)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
design service life
time period of exposure under service conditions after installation during which the absorber surface is
expected to meet the performance requirement
3.2
failure time
time period of exposure in the test at which the performance requirement limit is reached
3.3
solar absorptance, α
s
fraction of solar radiation energy absorbed by an absorber surface
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SIST EN ISO 22975-3:2014
ISO 22975-3:2014(E)
3.4
thermal emittance, ε
ratio between the energy per unit area radiated by a surface at a given temperature and the corresponding
energy radiated by a perfect black body at the same temperature
3.5
performance criterion function
PC
change in performance of an absorber surface in terms of changes in solar absorptance and thermal
emittance
4 Requirements and classification
4.1 For classification of the durability of the absorber surface, the following performance requirement
shall apply:
PC=−ΔΔαε+≤05,,00 05 (1)
s
where
Δα is the change in the solar absorptance defined as
s
Δα = α − α (2)
s s,t s,i
with α equal to the value of the solar absorptance at the actual time of the test or at service, and
s,t
with α equal to the initial value of solar absorptance
s,i
where
Δε is the change in the thermal emittance
Δε = ε − ε (3)
t i
with ε equal to the value of the thermal emittance at the actual time of the test or at service and
t
with ε equal to the initial value of thermal emittance.
i
NOTE 1 This performance criterion function is primarily based on location averaged values of the performance
[4]
of typical solar domestic hot water systems and combisystems. But, in the IEA Task 10 testing procedure
referred to, a slightly different definition of PC is used, namely PC = −Δα – 0,25 × Δε. Investigations made by the
s
[9]
IEA MSTC group, however, showed that a weighting factor of 0,5 for the thermal emittance is more appropriate.
NOTE 2 Higher values for the PC function may be used if considered more appropriate. PC < 0,10 should mean
that the optical performance of absorber surface, and thus also the performance of solar domestic hot water
system and combisystems, is allowed to be reduced to a level equal to 90 % of its original value during the design
[4]
service life time period.
4.2 Before durability testing of an absorber surface, all test specimens, sampled and prepared as
specified in 5.1, shall be characterized with respect to their value for solar absorptance, determined as
specified in 5.2, and their value for thermal emittance, determined as specified in 5.3.
To be qualified for testing, the set of test specimens shall have a standard deviation in the determined
values for solar absorptance of less than 0,01 and for the determined values of thermal emittance a
standard deviation less than 0,04.
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SIST EN ISO 22975-3:2014
ISO 22975-3:2014(E)
4.3 For coated absorber surfaces, three extra test specimens shall be prepared and the adhesion of
coating on those test specimens shall be assessed, as specified in 5.5.
For the absorber to be qualified for testing, the adhesion of coating shall be > 0,15 MPa for all test
specimens (ISO 4624).
NOTE If considered accurate enough, the adhesion of the coating may be assessed by a more simple method.
[1]
The method of ISO 2409 may be used and the requirement for satisfactory adhesion be set at the degree of 1.
[2]
Alternatively, some suitable method in ISO 2819 may be used.
4.4 For an absorber surface to be qualified with respect to its thermal stability, the procedure of
durability testing as specified in Clause 6 shall be applied.
An absorber surface with sufficient thermal stability shall meet the requirement for test results as is
specified in 6.4.
4.5 For an absorber surface to be qualified with respect to its resistance to condensed water when used
in a non-airtight solar collector with more or less uncontrolled ventilation of air in the solar collector, the
procedure of durability testing as specified in Clause 7 shall be applied.
An absorber surface with sufficient resistance to condensed water shall meet the requirements for test
results as are specified in 7.4.
4.6 If an absorber surface should be qualified with respect to its resistance to degradation caused by
sulfur dioxide as an airborne pollutant, the procedure of durability testing as specified in Clause 8 shall
be applied (optionally).
An absorber surface may be qualified for use in two classes of solar collectors; the two classes
representing different severity classes as regards atmospheric corrosivity.
Solar collector of type A: Airtight solar collector or solar collector with controlled ventilation of air in
the space between the absorber surface and the cover plate. At the top and at the bottom of the frame
of the solar collector, it should be equipped with ventilation holes. The atmospheric corrosivity at the
bottom part of the solar collector under service conditions may typically correspond to a corrosion rate
2
of zinc of 0,1 g/m per year.
Solar collector of type B: Non-airtight solar collector with more or less uncontrolled ventilation of air
in the solar collector. The atmospheric corrosivity at the bottom part of the solar collector under service
2
conditions corresponds to a corrosion rate of zinc of 0,3 g/m per year.
An absorber surface with sufficient resistance to degradation caused by sulfur dioxide in high humidity
air, either regarding only a type A solar collector or regarding both type A and type B solar collectors,
shall meet the requirements for test results as are specified in 8.6.
5 Test methods for assessing material properties as measure of absorber perfor-
mance
5.1 Sampling and preparation of test specimens
For durability testing, test samples with an absorber surface area of preferably (50 × 50) mm shall be
prepared. Sampling from larger pieces of absorber plate shall be made in such a way that variation in
the optical properties between the different test specimens is minimized. Three extra test samples are
also required for the assessment of the adhesion of the coating of un-aged test samples. For execution
of the complete programme of durability tests of this recommended procedure, a minimum of 18 test
samples are required.
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SIST EN ISO 22975-3:2014
ISO 22975-3:2014(E)
5.2 Sample conditioning
Determine the mean of solar absorptance and the mean of thermal emittance of three samples. Determine
the possible maximum absorber temperature for a collector covered with anti-reflection (AR) coating
according Table B.1. Temper all 18 samples at this maximum absorber temperature for at least 5 h with
an apparatus similar to that described in 6.2. Test three test samples for adhesion according to 5.5 and
proceed with the other 15 test samples if they pass the test.
5.3 Solar absorptance
Determine the value of the solar absorptance for each of the 15 test samples from reflectance
measurements as specified in A.1. For the complete set of test samples calculate also the mean value and
standard deviation of solar absorptance.
5.4 Thermal emittance
Determine also the value for the thermal emittance for each of the 15 test samples as is specified in A.2.
For the complete set of test samples calculate also the mean value and the standard deviation of thermal
emittance.
5.5 Adhesion
Determine the adhesion of the absorber coating either according to ISO 4624 (use the general method
for testing both rigid and deformable substrates when selecting test assembly and use test cylinders
with a diameter of 20 mm) or by means of a simpler method for assessment of adhesion (see 4.3) and
proceed as specified in the relevant standard.
6 Tests for assessing the thermal stability of absorber surfaces
6.1 Principle
6.1.1 High-temperature ageing is frequently used in many technical application areas for the assessment
of thermal stability of materials. A high temperature accelerates all kinds of processes, normally leading
to an increased rate of degradation of materials. For a selective absorber coating composed of small metal
particles, a high temperature enhances oxidation of metal decreasing mainly the absorptance of coating.
6.1.2 When installed in a single-glazed flat plate solar collector, an absorber surface is exposed to
a temperature which may
...
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