solar radition and daylight models

solar radition and daylight models

(Parte 1 de 6)

Solar Radiation and Daylight Models prelims.qxd 2/7/04 17:04 Page i prelims.qxd 2/7/04 17:04 Page i prelims.qxd 2/7/04 17:04 Page i

Solar Radiation and Daylight Models (with software available from companion web site)

T. Muneer Napier University, Edinburgh with a chapter on Solar Spectral Radiation by C.Gueymard, Solar Consulting Services, Denver, Colorado and H.Kambezidis, National Observatory of Athens, Athens

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Elsevier Butterworth-Heinemann Linacre House, Jordan Hill, Oxford OX2 8DP 200 Wheeler Road, Burlington, MA 01803

First published 1997 Second edition 2004

Copyright © 1997, 2004, Elsevier Ltd. All rights reserved

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ISBN 0 7506 5974 2

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Typeset by Charon Tec Pvt. Ltd, Chennai, India Printed and bound in Great Britain prelims.qxd 2/7/04 17:04 Page iv

For my parents prelims.qxd 2/7/04 17:04 Page v

Low in the earth

I lived in the realms of ore and stone; and then I smiled in many-tinted flowers; Then roving with the wild and wandering hours, Over earth and air and ocean’s zone,

In a new birth, I dived and flew, And crept and ran,

And all the secret of my essence drew Within a form that brought them all to view – And then my goal, Beyond the clouds, beyond the sky, In angel form; and then away Beyond the bounds of night and day*.

From Masnavi-ye-Manavi (Spiritual Couplets) by Jalaluddin Rumi (1207–73), Persian mystical poet.

*Metaphorically, the sun is a ‘whirling dervish’. The sect of the whirling dervishes was founded by Rumi’s followers.

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Introduction 35 2.1Monthly-averaged daily horizontal global irradiation36 2.2Monthly-averaged daily horizontal diffuse irradiation40 2.3 Annual-averaged diffuse irradiation 42 2.4Daily horizontal global irradiation45 2.5Daily horizontal diffuse irradiation46 2.6The inequality of the daily- and monthly-averaged regressions50 2.7Daily slope irradiation52 2.8 Exercises 56 References 57 prelims.qxd 2/7/04 17:04 Page vii


Introduction 61 3.1Monthly-averaged hourly horizontal global irradiation61 3.2Monthly-averaged hourly horizontal diffuse irradiation64 3.3Hourly horizontal global irradiation68 3.4Hourly horizontal diffuse irradiation100 3.5Hourly horizontal illuminance103 3.6 Daylight factor 118 3.7Solar climate characterisation122 3.8Frequency distribution of illuminance129 3.9 Exercises 133 References 135


Introduction 143 4.1Slope beam irradiance and illuminance144 4.2Sky clarity indices144 4.3Sky-diffuse irradiance models147 4.4Slope illuminance models167 4.5Radiance and luminance distributions173 4.6Luminance transmission through glazing188 4.7Quality control of cloud cover, sunshine, solar radiation and 190 daylight data 4.8Shadow band (shade ring) diffuse irradiance correction factor205 4.9 Exercises 216 References 216

5SOLAR SPECTRAL RADIATIONC. Gueymard and H. Kambezidis221 5.1Instruments and measurements221 5.2The earth’s atmosphere236 5.3 Extraterrestrial spectrum 247 5.4 Spectral modelling 250 5.5 Validation 270 5.6 Applications 278 References 296 viii CONTENTS prelims.qxd 2/7/04 17:04 Page viii


Introduction 317 7.1 Psychrometric properties 317 7.2Hourly temperature model320 References 322


CONTENTS ix prelims.qxd 2/7/04 17:04 Page ix prelims.qxd 2/7/04 17:04 Page x prelims.qxd 2/7/04 17:04 Page x

During the last decade there has been much research into solar radiation and daylighting in relation to environmental design. New data have been collected – particularly though the CIE/WMO Daylight Measurement Programme and its related projects – and new empirical models have been developed. Dr Muneer has been active in both aspects of the work.

Many numerical techniques now exist for calculating the distribution of radiation on and within buildings. This gives the designer a considerable predictive power, but it is at the cost of maintaining knowledge of a large and changing literature. Published algorithms vary in scope, accuracy and length; in some cases several alternative procedures are available for estimating the same physical quantity.

The value of this book is that an expert in the subject has made a personal selection of applicable formulae, and presented them in a comprehensive and consistent format, both on paper and in the form of computer programs. Books such as this are indispensable references for the research worker and for the practising engineer.

Peter Tregenza University of Sheffield prelims.qxd 2/7/04 17:04 Page xi prelims.qxd 2/7/04 17:04 Page xii prelims.qxd 2/7/04 17:04 Page xii

The aim of this work is to provide both a reference book and text on solar radiation and daylight models. The book grew out of author’s past 30 years of first hand experience of dealing with the relevant data from four continents: India, where the author grew up; USA, where he got his advanced schooling; Africa and UK where he taught and researched. Some of that work has been published in a series of technical articles. A concurrent and interesting activity in which the author is involved is the production of the new Chartered Institution of Building Services Engineers’Guide for Weather and Solar Data. This work provided an opportunity to liaise with colleagues from both sides of the Atlantic. The author was also fortunate to be awarded the Royal Academy of Engineering’s fellowship to visit Japan on an extended study leave. Through this opportunity the author was able to examine the abundance of solar irradiance and illuminance data now being collected in the Far East. The models presented herein are applicable for a very wide range of locations worldwide, in particular though for the European, American, Indian and other locations in the Pacific Rim.

The text also emphasises the importance of good structure in the presentation of the computational algorithms. The chapters and sections have been divided in a manner which represents not only a chronological development of the knowledge base, but also the algorithmic flow from coarse to a more refined basis of calculation.

FORTRAN is one of the most widely used programming languages in engineering applications. A special feature of this text is that it includes 43 programs, provided in the *.For and *.Exe formats. The former format enables the user to make any changes such as providing data via prepared electronic files or to embed these routines in their own simulation or other programs. For example, the earlier work performed by the author involved liaison with the developers of ESP and SERI-RES building energy simulation packages to incorporate some of the enclosed solar radiation routines. The *.Exe files are for users who may not have access to FORTRAN compilers. These files may be run directly from the DOS or Windows XP.

The enclosed suite of FORTRAN programs, available from companion web site, were designed and written by the author, based on several years of his research and consultancy experience. The programs cover almost all aspects of solar radiation and daylight related computations. All programs included herein are introduced via examples and the readers are encouraged to try them out as they progress through the book. Exercises as well as project work are additionally provided to enable further practice on the routines. Towards this end electronic files (data bases) with solar and other data are also available from companion web site.

The following program copying policy is to be maintained. Copies are limited to a one person/one machine basis. Backup copies may be kept by each individual reader as required. However, further distribution of the programs constitutes a violation of the copy prelims.qxd 2/7/04 17:04 Page xiii agreement and hence is illegal. Although prepared with great care and subject to rigorous quality control checks, neither the author nor the publisher warrant the performance or the results that may be obtained by using the enclosed suite of computer programs. Accordingly, the accompanying programs are licensed on an ‘as-is’basis. Their performance or fitness for any particular purpose is assumed by the purchaser or user of this book. The author welcomes suggestions for additions or improvements.

xivPREFACE TO THE FIRST EDITION prelims.qxd 2/7/04 17:04 Page xiv

Rapid sale of the first edition in a relatively short time plus the need to update information for an area of significant activity has dictated the need for the second edition of this book. Of late, the rapid deployment of solar photovoltaic technology across the globe has also demanded a need for the estimation of the local availability of the solar energy resource. In this respect the user will find that a considerable amount of new information, along with computational tools has been added in this edition.

New material and, in most cases, resulting computer programs on the following topics has been provided:

(a)Sun-path diagrams for abbreviated analysis. (b)New data files on measured data sets of irradiance and illuminance. (c)Distance between any two locations (solar radiation measurement site and location of its utilisation). (d)Characterisation of sky clarity indices and solar climate for any given location. (e)Corrections for sky-diffuse irradiance measurements using a shade-ring device. (f)Quality control of measured solar radiation and daylight data including outlier analysis. (g)Cloud radiation model. (h)Page radiation model (developed by Emeritus Professor John Page). (i)An extensive section on various forms of turbidity and their inter-relationships. (j)Newer generation of turbidity-based radiation models. (k)The European clear-sky solar radiation model (developed by Emeritus Professor

John Page). (l)Procedures for obtaining sunshine data from cloud cover information and vice versa. (m)Frequency of occurrence of diffuse and global illuminance. (n)Zenith luminance models. (o)New all-sky CIE standard for sky luminance distribution. (p) Spectral radiation. (q)Detailed measured data sets of solar radiation and other meteorological parameters. (r)Web sites that provide solar radiation and daylight data and other related information.

In response to a demand from readers and reviewers of this book a section on estimation of clear-sky solar irradiance for any part of the globe has been added.

Within the past 5 years there has been an acceleration of activity in the exploitation of solar energy and this has primarily resulted from protection of environment pressures. The Kyoto protocol for reduction of carbon dioxide has been an important instrument in this respect. Subsidies offered for the use of solar water heating and building integrated photovoltaic installations (BIPV technology) within the European Union countries have resulted in a rapid take-off of these and related technologies.

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Another contributing factor that will eventually lead to the use of solar power within the transport sector is the spiralling monetary and environment costs associated with the current use of fossil fuels. With the rapid decline in the oil reserves within the Gulf of Mexico basin, Iraq has become the linchpin in the US strategy to secure cheap oil. Between Saudi Arabia and Iraq, with their respective proven oil reserves of 262 and 112 billion barrels, a staggering 40% of world’s oil reserves is shared. With the US invasion of Iraq it appears that a new phase of ‘Energy wars’has started that may indeed spill over to other Opec countries. The repercussions of such actions and the fact that cheaper oil resulting from the ‘capture’ of oil reserves will lead to a faster consumption may indeed herald the true age of solar energy. In this respect world political leaders would be well advised to promote renewable energy technologies. That is the only and truly sustainable action for the abatement of the effects of an increase in atmospheric greenhouse gas loading.

xviPREFACE TO THE SECOND EDITION prelims.qxd 2/7/04 17:04 Page xvi

The author is indebted to the following individuals for their support: Z. Akber, W. A1-Naser, R. Angus, M. Asif, S. Baxter, K. Butcher, R. Claywell, F. Fairooz, S. Farhatullah, J. Fulwood, M. Gul, M. Gulam, B. Han, P. Haves, M. Holmes, A. Hussain, C. Kaldis, D. Kinghorn, Y. Koga, J. Kubie, A. Kudish, J. Lebrun, G. Levermore, P. Littlefair, G. Lopez, K. MacGregor, J. Mardaljevic, H. Nakamura, S. Natrajan, W. Platzer, G. Saluja, S. Samad, P. Tregenza, A. Wagner, G. Weir, A. Wright, B. Yallop, A. Young and X. Zhang.

The present text is the culmination of research undertaken by the author over the past two decades. Many organisations have either sponsored or actively supported author’s scholarly programme of work, noteworthy among them are: Scottish Education Department; Robert Gordon University; General Electric plc; University College, Oxford; The Leverhulme Trust; Université de Liège, Belgium; The Royal Academy of Engineering, London; The Chartered Institution of Building Services Engineers, London; and The British Council through its offices in Germany and Greece. Their contributions are gratefully acknowledged.

The help extended by the publishers Neil Warnock-Smith, Alex Hollingworth and

(Parte 1 de 6)