1、BRITISH STANDARD BS EN 61725:1997 IEC61725: 1997 Analytical expression for daily solar profiles The European Standard EN 61725:1997 has the status of a British Standard ICS 27.160BSEN 61725:1997 This British Standard, having been prepared under the directionof the Electrotechnical Sector Board, was
2、published underthe authority of the Standards Board and comes intoeffect on 15 December 1997 BSI 03-1999 ISBN 0 580 29027 1 National foreword This British Standard is the English language version of EN 61725:1997. It is identical with IEC61725:1997. The UK participation in its preparation was entrus
3、ted by Technical Committee GEL/82, Solar photovoltaic energy, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor r
4、elated international and European developments and promulgate them in the UK. A list of organizations represented on this committee can be obtained on request to its secretary. From 1 January 1997, all IEC publications have the number 60000 added to the old number. For instance, IEC27-1 has been ren
5、umbered as IEC60027-1. For a period of time during the change over from one numbering system to the other, publications may contain identifiers from both systems. Cross-references Attention is drawn to the fact that CEN and CENELEC Standards normally include an annex which lists normative references
6、 to international publications with their corresponding European publications. The British Standards which implement these international or European publications may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Fi
7、nd” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from lega
8、l obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, theEN title page, pages2to 5 andaback cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on th
9、e inside front cover. Amendments issued since publication Amd. No. Date CommentsBSEN 61725:1997 BSI 03-1999 i Contents Page National foreword Inside front cover Foreword 2 Text of EN 61725 3ii blankEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 61725 September 1997 ICS 27.160 English version A
10、nalytical expression for daily solar profiles (IEC 61725:1997) Expression analytique des profils solaires journaliers (CEI 61725:1997) Analytische Darstellung fr solare Tagesstrahlungsprofile (IEC 61725:1997) This European Standard was approved by CENELEC on 1997-07-01. CENELEC members are bound to
11、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 Central
12、 Secretariat or to any CENELEC 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 CENELEC member into its own language and notified to the Central Secretariat has the same statu
13、s as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CENELEC European Committee for E
14、lectrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B-1050 Brussels 1997 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref.
15、No. EN 61725:1997 EEN61725:1997 2 BSI 03-1999 Foreword The text of document 82/164/FDIS, future edition 1 of IEC61725, prepared by IEC TC 82, Solar photovoltaic energy systems, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN61725 on 1997-07-01. The following dates we
16、re fixed: Endorsement notice The text of the International Standard IEC61725:1997 was approved by CENELEC as a European Standard without any modification. Contents Page Foreword 2 Introduction 3 1 Scope 3 2 Definitions 3 3 Analytical solar irradiance profile 4 4 Ranges of validity 4 5 Examples 4 Fig
17、ure 1 Definition of symbols 3 Figure 2 Examples of analytical solar irradiance profiles 5 Figure 3 Range of validity of the analytical solar irradiance profiles 5 latest date by which the ENhas to be implemented at national level by publication of an identical national standard or by endorsement (do
18、p) 1998-04-01 latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 1998-04-01EN61725:1997 BSI 03-1999 3 Introduction This International Standard provides module manufacturers, installers and users with a means for synthesizing solar irradiance profiles. Thes
19、e profiles can be used as a reference in conjunction with user-supplied performance simulation programs for sizing and comparing photovoltaic systems. They can also be used in tenders or proposals. NOTETo compare PV systems, perform system sizing and evaluate specific PV system performance, other pa
20、rameters such as ambient temperature, wind speed, spectral irradiance distribution and PV device characteristics are required. 1 Scope This procedure provides a normative equation for analytically deriving a set of data points or a curve of irradiance versus time of day for a synthetic solarday. The
21、 coefficients of the normative equation for the analytical solar irradiance profiles are determined from measured or estimated values of maximum solar irradiance, daily solar irradiation and the number of daylight hours. These three input data define the curve of the analytical solar irradiance prof
22、iles. Depending on the objectives, these data may represent, for example, the worst winter day of a certain place, or the average day of a summer season, etc. CAUTION While the results from the normative equation match measured clear sky data reasonably well, it is not intended to predict or simulat
23、e a real day. A daily solar irradiance profile is defined based on user-selected values for peak irradiance, daily irradiation and total daylight hours. 2 Definitions The following symbols are defined and illustrated inFigure 1: G = solar irradiance, W.m 2 G max = the desired maximum solar irradianc
24、e at solar noon (t = 0), W.m 2 H = daily solar irradiation, Wh.m 2 H d = the desired daily solar irradiation for the synthesized solar day profile, Wh.m 2 t = time of day t 0 = time of sunrise + t 0 = time of sunset h = daylight hours (2.t 0 ), hours Figure 1 Definition of symbolsEN61725:1997 4 BSI
25、03-1999 3 Analytical solar irradiance profile The normative equation defining the analytical solar irradiance profiles (seeFigure 2) is: where s, the shape factor, is given by: where d, the data set factor, is given by: The data set factor shall be within the range of validity specified in clause4.
26、If the data set factor is not valid, then the input data shall be checked for plausibility. NOTEIf the daily solar irradiation value, H d , is not available, set the shape factor, s, to zero. The resulting curve will then be a cosine distribution (type C, seeFigure 2 andFigure 3). 4 Ranges of validi
27、ty To apply the normative equation (1) in a practical manner, the ratio, G/G maxshall be within the range: 5 Examples Figure 2 illustrates three example distributions. (1) (2) (3) The shape factor, s, shall be within the range: 1 # s # + 1 and the data set factor, d, within the range: 0,5 # d # 0,77
28、 (seeFigure 3).EN61725:1997 BSI 03-1999 5 Figure 2 Examples of analytical solar irradiance profiles Figure 3 Range of validity of the analytical solar irradiance profilesBS EN 61725:1997 IEC61725: 1997 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent nat
29、ional body responsible for preparing BritishStandards. It presents the UK view on standards in Europe and at the international level. It is incorporated by Royal Charter. Revisions BritishStandards are updated by amendment or revision. Users of BritishStandards should make sure that they possess the
30、 latest amendments or editions. It is the constant aim of BSI to improve the quality of our products and services. We would be grateful if anyone finding an inaccuracy or ambiguity while using this BritishStandard would inform the Secretary of the technical committee responsible, the identity of whi
31、ch can be found on the inside front cover. Tel:02089969000. Fax:02089967400. BSI offers members an individual updating service called PLUS which ensures that subscribers automatically receive the latest editions of standards. Buying standards Orders for all BSI, international and foreign standards p
32、ublications should be addressed to Customer Services. Tel:02089969001. Fax:02089967001. In response to orders for international standards, it is BSI policy to supply the BSI implementation of those that have been published as BritishStandards, unless otherwise requested. Information on standards BSI
33、 provides a wide range of information on national, European and international standards through its Library and its Technical Help to Exporters Service. Various BSI electronic information services are also available which give details on all its products and services. Contact the Information Centre.
34、 Tel:02089967111. Fax:02089967048. Subscribing members of BSI are kept up to date with standards developments and receive substantial discounts on the purchase price of standards. For details of these and other benefits contact Membership Administration. Tel:02089967002. Fax:02089967001. Copyright C
35、opyright subsists in all BSI publications. BSI also holds the copyright, in the UK, of the publications of the internationalstandardization bodies. Except as permitted under the Copyright, Designs and Patents Act 1988 no extract may be reproduced, stored in a retrieval system or transmitted in any f
36、orm or by any means electronic, photocopying, recording or otherwise without prior written permission from BSI. This does not preclude the free use, in the course of implementing the standard, of necessary details such as symbols, and size, type or grade designations. If these details are to be used for any other purpose than implementation then the prior written permission of BSI must be obtained. If permission is granted, the terms may include royalty payments or a licensing agreement. Details and advice can be obtained from the Copyright Manager. Tel:02089967070.
