Polymeric Materials for Solar Thermal Applications

Edited by Michael Köhl, Michaela G. Meir, Philippe Papillon, Gernot M. Wallner, Sandrin Saile

Solar Heating and Cooling

Köhl • M

eir • Papillon W

allner • Saile (Eds.)Polym

eric Materials for

Solar Thermal A

pplications

Bridging the gap between basic science and technological applications, this is the fi rst book devoted to polymers for solar thermal applications.Clearly divided into three major parts, the contributions are written by experts on solar thermal applications and polymer scientists alike. The fi rst part explains the fundamentals of solar thermal energy especially for representatives of the plastics industry and researchers. Part two then goes on to provide introductory information on polymeric materials and processing for solar thermal experts. The third part combines both of these fi elds, discussing the potential of polymeric materials in solar thermal applications, as well as demands on durability, design and building integration.With its emphasis on applications, this monograph is relevant for researchers at universities and developers in commercial companies.

Sandrin Saile, M.A.

Subtask A,Fraunhofer Institute forSolar Energy Systems ISE,Freiburg, Germany

Dr.-Ing. Michael Köhl

Operating Agent IEA SHCTask 39, Fraunhofer Institutefor Solar Energy Systems ISE,Freiburg, Germany

Dr. scient. Michaela Meir

Subtask Leader A,University of Oslo, Department of Physics, Oslo, Norway

Prof. Dr. mont. Gernot M. Wallner

Subtask Leader C, Institute of Polymeric Materials and Testing, Johannes KeplerUniversity, Linz, Austria

Dr.-Ing. Philippe Papillon

Subtask Leader B,INES Institut National del`Energie Solaire, CEA,Le Bourget du Lac, France

9 783527 332465

ISBN 978-3-527-33246-5

www.iea-shc.org www.wiley-vch.de

ISSN 2194-0665

57268File AttachmentCover.jpg

Edited by

Michael Köhl, Michaela G. Meir,

Philippe Papillon, Gernot M. Wallner,

and Sandrin Saile

Polymeric Materials for

Solar Thermal Applications

Related Titles

Wolf, E. L.

Nanophysics of Solar andRenewable Energy

2012

ISBN: 978-3-527-41052-1

Vogel, W., Kalb, H.

Large-Scale Solar Thermal Power

Technologies, Costs and Development

2010

ISBN: 978-3-527-40515-2

Keyhani, A., Marwali, M. N., Dai, M.

Integration of Green and RenewableEnergy in Electric Power Systems

2010

ISBN: 978-0-470-18776-0

Armaroli, N., Balzani, V.

Energy for a Sustainable World

From the Oil Age to a Sun-Powered

Future

2010

ISBN: 978-3-527-32540-5

Pagliaro, M., Palmisano, G., Ciriminna, R.

Flexible Solar Cells

2008

ISBN: 978-3-527-32375-3

Mathers, R. T., Meier, M. A. R. (eds.)

Green Polymerization Methods

Renewable Starting Materials, Catalysis

and Waste Reduction

2011

ISBN: 978-3-527-32625-9

Stolten, D., Emonts, B. (eds.)

Fuel Cell Science and Engineering

Materials, Processes, Systems and

Technology

2012

ISBN: 978-3-527-33012-6

Edited by Michael Köhl, Michaela Georgine Meir,Philippe Papillon, Gernot Michael Wallner, and Sandrin Saile

Polymeric Materials for Solar ThermalApplications

The Editors

Dr. Michael KöhlFraunhofer-Institutfür Solare Energiesysteme ISEDepartment Weathering and ReliabilityHeidenhofstraße 279110 FreiburgGermany

Dr. Michaela Georgine MeirUniversity of OsloDepartment of PhysicsPO Box 1048 Blindern0316 OsloNorway

Dr. Philippe PapillonINES Institut National del`Energie SolaireBoite postale 33273377 Le Bourget du LacFrance

Prof. Dr. Gernot Michael WallnerJohannes-Kepler-UniversitätAltenberger Straße 694040 LinzAustria

Sandrin Saile, M.A.Fraunhofer-Institutfür Solare Energiesysteme ISEDepartment of Weathering and ReliabilityHeidenhofstr. 279110 FreiburgGermany

All books published by Wiley-VCH are carefully pro-duced. Nevertheless, authors, editors, and publisher donot warrant the information contained in these books,including this book, to be free of errors. Readers areadvised to keep in mind that statements, data, illustra-tions, procedural details or other items may inadvertentlybe inaccurate.

Library of Congress Card No.: applied for

British Library Cataloguing-in-Publication DataA catalogue record for this book is available from theBritish Library.

Bibliographic information published bythe Deutsche NationalbibliothekThe Deutsche Nationalbibliothek lists this publication inthe Deutsche Nationalbibliografie; detailed bibliographicdata are available on the Internet at http://dnb.d-nb.de.

# 2012 Wiley-VCH Verlag & Co. KGaA,Boschstr. 12, 69469 Weinheim, Germany

All rights reserved (including those of translationinto other languages). No part of this book may bereproduced in any form – by photoprinting, microfilm, orany other means – nor transmitted or translated into amachine language without written permission from thepublishers. Registered names, trademarks, etc. used inthis book, even when not specifically marked as such, arenot to be consideredunprotected by law.

Print ISBN: 978-3-527-33246-5ePDF ISBN: 978-3-527-65963-0ePub ISBN: 978-3-527-65962-3mobi ISBN: 978-3-527-65961-6oBook ISBN: 978-3-527-65960-9ISSN: 2194-0665eISSN: 2194-8135

Composition Thomson Digital, Noida, IndiaPrinting and Binding Markono Print Media Pte Ltd,Singapore

Printed in SingaporePrinted on acid-free paper

Contents

About the Editors XVList of Contributors XVIIIEA Solar Heating and Cooling Programme XXIAcknowledgments XXIII

Part I 1

1 Principles 3Markus Peter

1.1 Introduction 31.2 Solar Irradiance in Technical Applications 61.3 Quantifying Useful Solar Irradiation 61.4 Solar Thermal Applications 71.5 Calculating the Solar Contribution 101.6 Conclusions 10

2 Solar Thermal Market 13Karl-Anders Weiß, Christoph Zauner, Jay Burch, and Sandrin Saile

2.1 Introduction 132.2 Collector Types 142.2.1 Unglazed Collectors 142.2.2 Flat Plate Collectors (FPC) 152.2.3 Evacuated Flat Plate Collector (EFPC) 162.2.4 Evacuated Tube Collectors (ETC) 162.2.5 Concentrating Collectors 162.2.6 Air Collectors 182.2.7 Market Share of Different Collector Types 182.3 Regional Markets 192.4 Market Trends 222.4.1 Global Market Development 222.4.2 Global Market Forecast 252.4.3 Focus on Europe 25

Links Providing Updated Market Data and Forecasts 26References 26

V

3 Thermal Solar Energy for Polymer Experts 29Philippe Papillon and Claudius Wilhelms

3.1 Solar Thermal Systems and Technical Requirements 293.2 Overview of Solar Thermal Applications 293.2.1 Swimming Pool Heating Applications 313.2.2 Domestic Hot Water Preparation for Single Family Houses 333.2.3 Domestic Hot Water Preparation for Multi-family Houses 393.2.4 Space Heating and DHW Preparation 403.2.5 Solar Cooling Applications 443.2.6 Solar Assisted District Heating 473.2.7 Process Heat Applications 493.3 Solar Thermal Collectors 503.3.1 Basic Principle of a Solar Thermal Collector 503.3.2 Unglazed Collector 533.3.3 Glazed Flat Plate Collector 563.3.4 Evacuated Tubes 583.3.5 Other Types of Collectors 603.3.6 Selective Coatings for Solar Absorbers 623.4 Small to Medium Size Storages 633.4.1 Classification of Heat Storages 643.4.2 Domestic Hot Water Storages 653.4.3 Non-domestic Hot Water Storages 673.4.4 Non-water Based Storage 683.5 Sources of Further Information 703.5.1 Related International Energy Agency Solar Heating and

Cooling Tasks 703.5.2 Web Sites and Projects Related to Solar Thermal Systems 70

References 70

4 Conventional Collectors, Heat Stores, and Coatings 73Stephan Fischer, Harald Drück, Stephan Bachmann,Elke Streicher, Jens Ullmann, and Beate Traub

4.1 Collectors 734.1.1 Transparent Covers 754.1.2 Absorber Plate Risers and Manifolds 754.1.3 Absorber Coatings 764.1.4 Thermal Insulation 774.2 Material Properties of Insulations 794.2.1 Casing 804.2.2 Sealing 804.2.3 Collector Mounting Structures 804.3 Heat Store 814.4 Other Components 844.5 Analysis of Typical Combisystems 864.5.1 Combisystems Analyzed 86

VI Contents

4.5.2 Weight of the Components 864.5.3 Materials Used in the Systems 864.5.4 Materials Used in the Components 884.6 Definition of Polymeric Based Solar Thermal Systems 924.7 Life Cycle Assessment Based on Cumulated Energy Demand, Energy

Payback Time, and Overall Energy Savings 974.8 Cumulated Energy Demand, Energy Payback Time, and Overall

Energy Savings for Conventional and Polymeric Based DomesticHot Water Systems 98

4.8.1 System Boundary 1004.8.2 Cumulative Energy Demand 1004.8.2.1 Cumulative Energy Demand for Production 1004.8.3 Conventional Reference System for the Determination of the

Primary Energy Saved by the Solar Thermal System 1014.8.4 Fractional Energy Savings 1024.8.5 Lifetime 1024.8.6 Calculation for Solar Domestic Hot Water Systems 1024.8.6.1 Materials and Masses of the Systems Used for the

Reference System (DHW1) 1024.8.6.2 Materials and Masses of the Systems Used for the Polymeric

System (DHW2) 1024.8.6.3 Input Values and Results for Determination of the CED 1024.8.6.4 Overall Energy Savings and Energy Payback Time 104

References 106

5 Thermal Loads on Solar Collectors and Options fortheir Reduction 107Christoph Reiter, Christoph Trinkl, and Wilfried Zörner

5.1 Introduction 1075.2 Results of Monitoring Temperature Loads 1075.3 Measures for Reduction of the Temperature Loads 114

References 117

6 Standards, Performance Tests of Solar Thermal Systems 119Stephan Fischer and Christoph Zimmermann

6.1 Introduction 1196.2 Collectors 1196.2.1 Testing of Solar Collectors for Durability and Reliability 1206.2.2 Testing of Solar Collectors for Thermal Performance 1206.3 Solar Thermal Systems 1216.3.1 Testing of Solar Thermal Products 1246.3.1.1 CSTG Method 1256.3.1.2 DST Method 1256.3.2 CTSS Method 1256.4 Conclusion 125

Contents VII

Part II 127

7 Plastics Market 129Katharina Resch and Gernot M. WallnerReferences 134

8 Polymeric Materials 135Gernot M. Wallner, Reinhold W. Lang, and Karl Schnetzinger

8.1 Introduction 1358.2 Material Structure and Morphology of Polymers 1368.3 Inner Mobility and Thermal Transitions of Polymers 1438.4 Polymer Additives and Compounds 1468.4.1 Stabilizing Additives 1478.4.2 Antioxidants 1478.4.3 Light Stabilizers 1488.4.4 Modifying Additives 148

References 149

9 Processing 1519.1 Structural Polymeric Materials 151

Helmut Vogel9.1.1 Introduction to Polymer Processing 1519.1.2 Extrusion Based Processes 1529.1.2.1 Profile Extrusion 1529.1.2.2 Film Blowing 1549.1.2.2.1 Cast Film Extrusion 1549.1.2.3 Calender Stack Process for Plates 1559.1.2.4 Blow Molding 1579.1.2.4.1 Extrusion Blow Molding 1599.1.2.4.2 Injection Blow Molding 1609.1.3 Injection Molding 1619.1.3.1 Injection Molding Cycle 1629.1.4 Thermoforming 1649.1.5 Fiber Reinforced Polymer 1659.1.5.1 Sheet Molding Compound (SMC) 1659.1.5.2 Glass Mat Thermoplastics (GMT) 165

References 166

9.2 Paint Coatings for Polymeric Solar Absorbers and Their Applications 167Ivan Jerman, Matja�z Ko�zelj, Lidija Slemenik Per4se, and Boris Orel

9.2.1 Outline of Content 1679.2.2 General Remarks about Selective Paint Coatings 1689.2.3 Preparation of Selective Paints 1699.2.3.1 Effect of Dispersants on Pigment Dispersions 1709.2.3.2 Dispersants 171

VIII Contents

9.2.3.3 Trisilanol T7 POSS Dispersants for Colored TISS Paint Coatings 1749.2.4 Application Techniques for Spectrally Selective Paints 1759.2.4.1 Brush and Hand Roller Application 1759.2.4.2 Spray Application 1769.2.4.3 Case Study: Application of TISS Paint on a Polymeric Substrate

by Using Simple Silane Dispersants 1789.2.4.4 Direct Coating Application Techniques 1799.2.4.5 Dip Coating 1809.2.4.6 Dip and Flow Coating 1809.2.4.7 Roll Coating 1829.2.4.8 Coil Coating 1829.2.5 Conclusions 185

References 185

10 Polymer Durability for Solar Thermal Applications 187Susan C. Mantell and Jane H. Davidson

10.1 Introduction 18710.2 Polymeric Glazing 18810.3 Polymeric Absorbers and Heat Exchangers 18910.3.1 Overview of Relevant Polymer Material Properties and

Requirements 19110.3.2 Additional Material Considerations 19610.3.2.1 Fillers to Improve Thermal Conductivity and Strength 19610.3.2.2 Scaling 19810.3.2.3 Oxidation 19910.3.3 Absorbers 20110.3.3.1 Material Selection 20110.3.3.2 Polymer Absorber Applications 20310.3.4 Heat Exchangers 20410.3.4.1 Material Selection 20510.3.4.2 Polymer Heat Exchanger Applications 20510.4 Conclusion 206

References 207

11 Plastics Properties and Material Selection 211Ulrich Endemann and Andreas Mägerlein

11.1 Introduction 21111.2 How to Select the Right Material 21111.3 Material Databases 21211.4 Selection Criteria 21311.5 Real Life Example: Standard Collector in Plastic (1:1 Substitution) 21311.5.1 Preselection 21411.5.1.1 Housing 21511.5.1.2 Absorber 21611.5.1.3 Sealing 217

Contents IX

11.5.1.4 Glazing 21711.5.1.5 Insulation 21711.6 Summary 218

Part III 219

12 State of the Art: Polymeric Materials in Solar Thermal Applications 221Michaela Meir, Fabian Ochs, Claudius Wilhelms, and Gernot Wallner

12.1 Solar Collectors 22112.1.1 Pool Absorbers 22112.1.2 Material Substitution in Conventional Collector Designs 22212.1.3 Glazed Flat-Plate Collectors with Polymeric Absorbers 22412.1.4 Air Collector Systems 22412.1.5 Integrated Storage Collectors and Thermosiphon Systems 22512.1.6 Collector Glazing 22712.1.7 Integrated and Multifunctional Applications 22812.1.8 Absorber Designs from a Polymer Engineering Point

of View 22912.1.9 Summary 23112.2 Small to Mid-Sized Polymeric Heat Stores 23112.2.1 Introduction 23112.2.2 Challenges 23512.3 Polymeric Liners for Seasonal Thermal Energy Stores 23512.3.1 Envelope Design of Thermal Energy Stores 23612.3.2 Liner of Pilot and Research Thermal Energy Stores 23712.3.3 Summary 239

References 241

13.1 Structural Polymeric Materials – Aging Behavior of Solar AbsorberMaterials 243Suanne Kahlen, Gernot M. Wallner, and Reinhold W. Lang

13.1.1 Introduction and Scope 24313.1.2 Methodology 24413.1.3 Results, Discussion, and Outlook 24613.1.3.1 Characterization of Physical and Chemical Aging of Polymeric

Solar Materials by Mechanical Testing 24613.1.3.2 Aging Behavior of Polymeric Solar Absorber Materials – Part 1:

Engineering Plastics 24713.1.3.3 Aging Behavior of Polymeric Solar Absorber Materials – Part 2:

Commodity Plastics 24813.1.3.4 Aging Behavior and Lifetime Modeling for Polymeric Solar

Absorber Materials 24913.1.3.5 Aging Behavior of Polymeric Solar Absorber Materials: Aging

on Component Level 250References 252

X Contents

13.2 Thermotropic Layers for Overheating Protection of all-PolymericFlat Plate Solar Collectors 255Katharina Resch, Robert Hausner, Gernot M. Wallner, and Reinhold W. Lang

13.2.1 Introduction 25513.2.2 Materials and Sample Preparation 25613.2.3 Physical Characterization of the Polymers 25713.2.4 Results and Discussion 25813.2.5 Effect of Thermotropic Layers on Collector Efficiency and

Stagnation Temperatures 26213.2.6 Outlook 263

References 264

13.3 Application of POSS Compounds for Modification of the WettingProperties of TISS Paint Coatings 267Ivan Jerman, Boris Orel, and Matja�z Ko�zelj

13.3.1 Introduction 26713.3.2 Wetting of Surfaces 27013.3.2.1 Basic Principles – Learning from Nature 27013.3.2.2 Surface Energy 27213.3.2.3 Surface Roughness 27313.3.2.4 Morphology of TISS Paint Coatings 27513.3.3 POSS Nanocomposites as Low Surface Energy Additives

for Coatings 27613.3.3.1 Synthesis and Structural Characteristics of POSS Molecules 27613.3.4 Anti-wetting Properties of Coatings with Smooth Surfaces –

Lacquers for Polymeric Glazing 27813.3.4.1 Structure of Fluoropolymer Resin Binders – General Remarks 27913.3.4.2 Contact Angles and Surface Properties of Lumiflon Resin Binders 28013.3.4.3 Interaction of POSS – SEMMicrographs and Optical Transmission 28113.3.5 Anti-wetting Properties of Coatings on Rough Surfaces – TISS

Paint Coatings 28213.3.5.1 Wetting Properties of TISS Coatings 28213.3.6 Conclusions 284

References 284

14 Conceptual Design of Collectors 287Karl-Anders Weiss, Steffen Jack, Axel Müller, and John Rekstad

14.1 Introduction 28714.2 Calculation of Collector Efficiency 28714.3 Flow Optimization 29114.4 Optimization of the Fluid Dynamics in Polymeric Collectors 29114.4.1 Optimization of the Absorber 29114.4.2 Optimization of the Fluid Dynamics in the Header 29214.4.3 Optimization of the Fluid Dynamics Non-rectangular Collectors 29214.5 Collector Mechanics 295

Contents XI

14.6 Conclusion 297References 299

15 Collectors and Heat Stores 301Stefan Brunold, Philippe Papillon, Micha Plaschkes,John Rekstad, and Claudius Wilhelms

15.1 Introduction 30115.2 Solar Absorber Made of High-Performance Plastics 30115.2.1 General Presentation 30115.2.2 Detailed Description 30215.2.3 Experiences with Development of the Products 30715.3 Flate Plate Collector with Overheating Protection 30715.3.1 General Presentation 30715.3.2 Detailed Description 30715.3.3 Experience Gained with Development of the Products 30915.4 Flat Plate Collectors with a Thermotropic Layer 31015.4.1 General Presentation 31015.4.2 Detailed Description 31015.4.3 Experience Gained with Development of the Products 31315.5 Solar Storage Tank with Polymeric Sealing Technology

with Storage Volumes from 2 to 100 m3 31315.5.1 General Presentation 31315.5.2 Detailed Description 31415.5.3 Experience Gained with Development of the Products 314

References 317

16 Durability Tests of Polymeric Components 319Stefan Brunold,Florian Ruesch,Roman Kunic, John RekstadMichaela Meir, and Claudius Wilhelms

16.1 Introduction 31916.2 Twenty Years Outdoor Weathering of Polymeric Materials for

use as Collector Glazing 32016.2.1 Introduction 32016.2.2 Material Selection 32016.2.3 Exposure 32116.2.4 Evaluation of Optical Properties 32216.2.5 Results 32316.2.5.1 PMMA 32316.2.5.2 PC 32516.2.5.3 Fluoropolymers 32616.2.5.4 UP 32916.2.5.5 PET and PVC 33016.2.6 Conclusion 33016.3 Accelerated Lifetime Testing of a Polymeric Absorber Coating 33216.3.1 Introduction 332

XII Contents

16.3.2 Application of the ALT Test Procedure on the TISS PaintedAbsorber 333

16.3.3 Adaption of the ALT Procedure to the TISS Painted Absorber 33316.3.4 Conclusions 33716.4 Evaluation of Temperature Resistance of a Polymer Absorber in

a Solar Collector 33716.4.1 Background 33716.4.2 Method 33816.4.3 Experiments 33916.4.4 Service Life for a Plastics Absorber Made in PPS 34116.4.5 Conclusion 34316.5 Determination of Water Vapor Transport through Polymeric

Materials at Raised Temperatures 34316.5.1 Measurement Setup/Testing Rig 34416.5.2 Results 34616.5.3 Conclusion 347

References 347

17 Architecturally Appealing Solar Thermal Systems – A Marketing Toolin Order to Attract New Customers and Market Segments 351Ingvild Skjelland, John Rekstad, Karl-Anders Weiss, andMaria Christina Munari Probst

17.1 Introduction 35117.2 Architectural Integration as a Marketing Tool 35117.3 Web Database 35317.4 Examples 354

References 357

18 Obstacles for the Application of Current Standards 359Stephan Fischer, Christoph Zauner, Philippe Papillon, Andreas Bohren,Stefan Brunold, and Robert Hausner

18.1 Introduction 35918.2 Internal Absorber Pressure Test 35918.2.1 Description of the Specific Test and Test Procedure 35918.2.2 Why this is a Problem for Polymeric Collectors or Why this Test Does

not Reflect the Requirements for Polymeric Collectors 36018.2.3 Possible Alternative Procedure 36018.3 High-Temperature Resistance and Exposure Tests 36018.3.1 Description of the Specific Test and Test Procedure 36018.3.2 Why this is a Problem for Polymeric Collectors or Why this Test does

not Reflect the Requirements for Polymeric Collectors 36118.3.3 Possible Alternative Procedure 36118.3.3.1 General Comments 36118.3.3.2 Comments on Overheating Protection 36218.3.3.3 Passive Devices 362

Contents XIII

18.3.3.4 Active Devices 36318.4 Mechanical Load Test 36318.4.1 Description of the Specific Test and Test Procedure 36318.4.2 Why this is a Problem for Polymeric Collectors or Why this

Test does not Reflect the Requirements for Polymeric Collectors 36418.4.2.1 Typical Data for Snow Load (According to EN12975 and to

PV Norms such as EN61646 etc.) 36418.4.2.2 Typical Data for Wind Load (According to EN12975 and to

PV Norms such as EN61646 etc.) 36418.4.2.3 Typical Normative Requirements 36418.4.3 Possible Alternative Procedure 36518.5 Impact Resistance Test 36518.5.1 Description of the Specific Test and Test Procedure 36518.5.2 Why this is a Problem for Polymeric Collectors or Why this Test does

not Reflect the Requirements for Polymeric Collectors 36518.5.2.1 Typical Data for Steel Ball Test of 150 g (According to EN12975) 36618.5.2.2 Typical Data for Ice Stones Test of Different Sizes (According to

EN12975 and to PV Norms such as EN61646 etc.) 36618.5.2.3 Typical Normative Requirements 36618.5.3 Possible Alternative Procedure 36618.6 Discontinuous Efficiency Curves 36618.6.1 Description of the Specific Test and Test Procedure 36618.6.2 Problems Regarding Polymeric Collectors 36718.6.2.1 The Limit is Dependent Mainly on the Absorber Temperature 36718.6.2.2 The Limit is Dependent on the Absorber Temperature and on

the Ambient Temperature 36718.6.3 Possible Alternative Procedures 36818.6.3.1 Determination of the Validity Limit for the Standard Procedures 36818.6.3.2 Determination of Stagnation Temperature 369

Reference 370

Glossary 371

Polymeric Materials 371Abbreviations 371Terms and Definitions 372Solar Thermal Systems 379Abbreviations 379Terms and Definitions 379

Index 385

XIV Contents

About the Editors

Dr.-Ing. Michael Köhl, physicist, has been actively involvedin the field of solar energy conversion since 1977. He pre-sently works on service-life analysis of solar collectors andphotovoltaic modules in the department Weathering andReliability at Fraunhofer ISE. He was the coordinator ofthe EU projects SUNFACE and SOLABS and leader of Sub-task 5 of the IP PERFORMANCE. Dr. Köhl is the currentOperating Agent of the Task 39 ‘‘Polymeric Materials forSolar Thermal Applications’’of the Solar Heating and Cool-ing Programme of the International Energy Agency IEA.

Dr. scient. Michaela Meir, physicist, has been working withR&D on solar thermal and energy systems for more than 15years, with particular focus on the development of solarcollectors using polymeric materials. She is presentlyemployed part-time by the University of Oslo and by AventaAS. She is Chairman of the Norwegian Solar Energy Societyboard and leader of Subtask A ‘‘Information’’of IEA SHCTask 39.

Sandrin Saile, M.A. received her M.A. in British and NorthAmerican Cultural Studies from the University of Freiburg.She joined the Fraunhofer ISEs department ‘‘Weatheringand Reliability’’ in 2009 where she is responsible for themanagement and dissemination of the departments solarthermal activities, in particular the projects SCOOP andSpeedColl. Within IEA SHC Task 39 she is mainly activein Subtask A ‘‘Information’’ and played an active role inestablishing the Solar Heating and Cooling Series.

XV

Prof. Dr. mont. Gernot M. Wallner, graduated with a ‘‘Diplo-mingenieur’’ degree in Polymer Engineering and Science atthe University of Leoben (Austria) in 1994, and he obtained aPhD degree in the same field at the University of Leoben in2000. In 2008 Prof. Wallner obtained a Venia Docendi in thefield of ‘‘Functional Polymeric Materials’’ with special focuson solar energy applications. Since 2010, Prof. Wallner hasbeen Deputy Head at the Institute of Polymeric Materials andTesting (IPMT) at the Johannes Kepler University Linz (JKU,

Austria). Prof. Wallner is a member and leading person in several solar relatedworking groups and committees. Since the establishment of IEA SHC Task 39 in2006, he has been leader of the Subtask C ‘‘Materials’’.

Dr.-Ing. Philippe Papillon has been a senior expert in the fieldof solar thermal energy at INES (Institut National de lEnergieSolaire - CEA) since December 2005. He has been active inthe field of thermal solar energy for more than 20 years, andhas experience as coordinator as well as WP leader in Eur-opean projects and also large national research projects.Beyond his research activities within INES, he is also anexpert in European and French standardization committees,and is a member of the European Technology Platform on

Renewable Heating and Cooling board. From 2006–2010 he acted as leader of theIEA SHC Task 39 Subtask B ‘‘Collectors’’.

XVI About the Editors

List of Contributors

Stephan BachmannUniversity of StuttgartInstitute for Thermodynamics andThermal Engineering (ITW)Pfaffenwaldring 670550 StuttgartGermany

Andreas BohrenUniversity of Applied SciencesRapperswil HSRInstitute for Solar Technology SPFOberseestr. 108640 RapperswilSwitzerland

Jay Burch1617 Cole Blvd.MS 52/2Golden, CO 80401USA

Stefan BrunoldUniversity of Applied SciencesRapperswil HSRInstitute for Solar Technology SPFOberseestr. 108640 RapperswilSwitzerland

Jane H. DavidsonUniversity of MinnesotaDepartment of MechanicalEngineering111 Church Street SEMinneapolis, MN 55455USA

Harald Dr€uckUniversity of StuttgartInstitute for Thermodynamics andThermal Engineering (ITW)Pfaffenwaldring 670550 StuttgartGermany

Ulrich EndemannBASF – The Chemical CompanySegment Management UniversalBASF SE, E-KTE/IU-F 20667056 LudwigshafenGermany

Stephan FischerUniversity of StuttgartInstitute for Thermodynamics andThermal Engineering (ITW)Pfaffenwaldring 670550 StuttgartGermany

jXVII

Robert HausnerAEE‐Institute for SustainableTechnologiesFeldgasse 198200 GleisdorfAustria

Steffen JackBäckerstr. 5031785 HamelnGermany

Ivan JermanNational Institute of ChemistryL02 Laboratory for the Spectroscopyof MaterialsHajdrihova 191000 LjubljanaSlovenia

Suanne KahlenPolymer Competence Center LeobenGmbH Roseggerstr. 128700 LeobenAustria

and

Borealis Polyolefine GmbHSt. Peter-Str. 254021 LinzAustria

Matja9z Ko9zeljNational Institute of ChemistryL02 Laboratory for the Spectroscopyof MaterialsHajdrihova 191000 LjubljanaSlovenia

Roman KunicFaculty of Civil and GeodeticEngineeringJamova 21000 LjubljanaSlovenia

Reinhold W. LangJohannes Kepler UniversityInstitute of Polymeric Materials andTestingAltenberger Str. 694040 LinzAustria

Andreas M€agerleinBASF – The Chemical CompanySegment Management UniversalBASF SE, E-KTE/IU-F 20667056 LudwigshafenGermany

Susan C. MantellUniversity of MinnesotaDepartment of MechanicalEngineering111 Church Street SEMinneapolis, MN 55455USA

Michaela MeirUniversity of OsloDepartment of PhysicsPost Box 1048 Blindern0316 OsloNorway

Axel MüllerHTCO GmbHRabenkopfstraße 479102 Freiburg i.Br.Germany

Maria Christina Munari ProbstEcole Polytechnique Federale deLausanneLE 0 04 (Building LE)Station 181015 LausanneSwitzerland

XVIIIj List of Contributors

Fabian OchsUniversity of StuttgartInstitute for Thermodynamics andThermal Engineering (ITW)Pfaffenwaldring 670550 StuttgartGermany

Boris OrelNational Institute of ChemistryL02 Laboratory for the Spectroscopyof MaterialsHajdrihova 191000 LjubljanaSlovenia

Philippe PapillonInstitut National de l’Energie SolaireCommissariat à l’Energie Atomiqueet aux Energies Alternatives50 avenue du Lac Leman73377 Le Bourget du LacFrance

Markus Peterdp2 – Intelligent use of EnergyMengeweg 259494 SoestGermany

Lidija Slemenik Per9seNational Institute of ChemistryL02 Laboratory for the Spectroscopyof MaterialsHajdrihova 191000 LjubljanaSlovenia

Micha PlaschkesMAGEN-ECOENERGYProduct and Process DevelopmentKibutz Magen-85465Israel

Christoph ReiterIngolstadt University of AppliedSciencesEsplanade 1085049 IngolstadtGermany

John RekstadUniversity of OsloDepartment of PhysicsPost Box 1048 Blindern0316 OsloNorway

Katharina ReschUniversity of LeobenInstitute of Materials Science andTesting of PlasticsOtto-Gl€ockel-Str. 28700 LeobenAustria

Florian RueschUniversity of Applied SciencesRapperswil HSRInstitute for Solar Technology SPFOberseestr. 108640 RapperswilSwitzerland

Sandrin SaileFraunhofer Institute for Solar EnergySystems ISEDepartment Weathering andReliabilityHeidenhofstr. 279110 FreiburgGermany

Karl SchnetzingerAdvanced Polymer CompoundsKurzheim 228793 GaiAustria

List of Contributors jXIX

Ingvild SkjellandAventa Solar/Aventa ASTrondheimsveien 436a0962 OsloNorway

Elke StreicherUniversity of StuttgartInstitute for Thermodynamics andThermal Engineering (ITW)Pfaffenwaldring 670550 StuttgartGermany

Beate TraubUniversity of StuttgartInstitute for Thermodynamics andThermal Engineering (ITW)Pfaffenwaldring 670550 StuttgartGermany

Christoph TrinklIngolstadt University of AppliedSciencesEsplanade 1085049 IngolstadtGermany

Jens UllmannInstitute for Thermodynamics andThermal Engineering (ITW)Pfaffenwaldring 670550 StuttgartGermany

Helmut VogelUniversity of Osnabr€uckAlbrechstr. 3049076 Osnabr€uckGermany

Gernot M. WallnerJohannes Kepler UniversityInstitute of Polymeric Materials andTestingAltenberger Str. 694040 LinzAustria

Karl-Anders WeißFraunhofer Institute for Solar EnergySystems ISEDepartment Weathering andReliabilityHeidenhofstr. 279110 FreiburgGermany

Claudius WilhelmsUniversity of KasselKurt-Wolters-Str. 6934125 KasselGermany

Christoph ZaunerAITAustrian Institute of TechnologyGiefinggasse 21210 ViennaAustria

Christoph ZimmermannInstitute for Thermodynamics andThermal Engineering (ITW)Pfaffenwaldring 670550 StuttgartGermany

Wilfried Z€ornerIngolstadt University of AppliedSciencesEsplanade 1085049 IngolstadtGermany

XXj List of Contributors

IEA Solar Heating and Cooling Programme

The Solar Heating and Cooling Programme was founded in 1977 as one of the firstmultilateral technology initiatives (‘‘Implementing Agreements’’) of the Interna-tional Energy Agency. Its mission is to ‘‘advance international collaborative effortsfor solar energy to reach the goal set in the vision of contributing 50% of the lowtemperature heating and cooling demand by 2030.’’

The member countries of the Programme collaborate on projects (referred to as‘‘Tasks’’) in the field of research, development, demonstration (RD&D), and testmethods for solar thermal energy and solar buildings.

A total of 47 such projects have been initiated to date, 38 of which have beencompleted. Research topics include:

� solar space heating (Tasks 19, 26, 44),� solar heat for industrial or agricultural processes (Tasks 29, 33, 34, 49),� solar district heating (Tasks 7, 45),� solar cooling (Tasks 25, 38, 48),� solar buildings/architecture (Tasks 11, 13, 20, 21, 22, 23, 28, 31, 37, 41, 47),� materials/components for solar heating and cooling (Tasks 10, 18, 27,

32, 39, 42),� standards, certification & test methods (Tasks 14, 34, 43),� resource assessment (Tasks 17, 36),� storage of solar heat (Tasks 7, 42).

In addition to the project work, several special activities – Memorandum ofUnderstanding with solar thermal trade organizations, statistics collection andanalysis, conferences and workshops – have been undertaken. An annual inter-national conference on Solar Heating and Cooling for Buildings and Industry waslaunched in 2012. The first of these conferences, SHC2012, was held in SanFrancisco.

XXI

Current members of the IEA SHC are:Australia Finland SingaporeAustria France South AfricaBelgium Italy SpainCanada Mexico SwedenDenmark Netherlands SwitzerlandEuropean Commission Norway United StatesGermany Portugal

Further information:For up to date information on the IEA SHCwork, including many free publications,please visit the web site www.iea-shc.org

XXII IEA Solar Heating and Cooling Programme

Acknowledgments

The process of compiling this handbook was a collaborative effort involving theexperience and expertise of many people. While the handbook consists of separatechapters with individual authors responsible for their own contents, it is also theproduct of a progressive development process to which all participating Task 39experts (see, for example, http://www.iea-shc.org/about/members/task.aspx?Task=39) contributed either during discussions in experts meetings or by sharingtheir experience and the results of numerous funded research projects.

As it is not possible to thank all of the many people involved, we hereby acknowl-edge the essential support from funding agencies and the industry as a whole.Furthermore, we thank the Task 39 experts for their active and inspiring work – theircontributions greatly added to the vivid and dynamic nature of Task 39 and naturallyalso to the contents of this book.

As is the case with every publication, the final result would have not been feasiblewithout the help of a great number of people working hard behind the scenes. Wewould like to take this opportunity to acknowledge their passion and endurance,which have allowed the project to come to fruition. The editors and authors are verygrateful to Bente Flier, Lesley Belfit, Dr. Frank Weinreich, and the rest of the Wiley-VCH team for their patient and constructive support throughout the project as wellas to Sarah Greuter and Raphael Präg for their tireless assistance in preparing themanuscript.

Michael Köhl, Freiburg, GermanySandrin Saile, Freiburg, Germany

Michaela Meir, Oslo, NorwayPhilippe Papillon, Chambery, France

Gernot M. Wallner, Linz, Austria

XXIII

Part I

Polymeric Materials for Solar Thermal Applications, First Edition. M. K€ohl, M.G. Meir, P. Papillon,G.M. Wallner, and S. Saile� 2012 Wiley-VCH Verlag GmbH & Co. KGaA. Published 2012 by Wiley-VCH Verlag GmbH & Co. KGaA.

j1

1PrinciplesMarkus Peter

1.1Introduction

Apart from fossil and nuclear energy sources, so-called renewable energy is available.The already located and predicted resources of fossil fuels and fissile materialsevidently underline that in a limited system like the earth only renewable energy canassure a long-lasting existence. Three categories of renewable energies, based ondifferent primary sources, are available:

. solar energy: thermonuclear (fusion) processes in the sun;

. geothermal energy: residual heat from the genesis of earth and decay of isotopesinside the earth;

. tidal energy: gravity caused by planetary (orbs) motion.

Within the ability and experience of humankind only these energy sources areinexhaustible.

Renewable energy like heat in the upper lithosphere or wind is a mixture of two ormore primary sources. In the case of heat in the upper lithosphere geothermal andsolar energy are relevant, for wind the rotation of earth, planetary motion, and solarirradiance are important.

The largest flux of energy available on earth is solar irradiation. The total poweremitted by the sun is approximately 380� 1018 MW. This corresponds to 62.6MWm�2 related to a surface calculated from the diameter of the sun. Even sources withhigh capacity too, the potential of geothermal and tidal energy are orders ofmagnitude smaller than that of solar irradiation.1)

The energy emitted by the sun results from different fusion processes (mainly thefusion of 4Hþ to 1He). Owing to the distance between the sun and earth (approx-imately 1.5� 108 km) the electromagnetic radiation arrives at the outer atmospherehighly diluted, with a power density of approximately 1367Wm�2. This so-calledsolar constant, measured outside the atmosphere, has a fluctuation range of about

1) Solar energy approximately 5.6� 106 EJ a�1; geothermal energy approximately 9.7� 102 EJ a�1; tidalenergy approximately 9.4� 101 EJ a�1.

Polymeric Materials for Solar Thermal Applications, First Edition. M. K€ohl, M.G. Meir, P. Papillon,G.M. Wallner, and S. Saile� 2012 Wiley-VCH Verlag GmbH & Co. KGaA. Published 2012 by Wiley-VCH Verlag GmbH & Co. KGaA.

j3

�3.5% that is mainly caused by the variation of the distance between the sun and theearth, sun activity, and sunspots (Figure 1.1).

The fraction of energy reaching the earth is only 0.045 � 10�6% of the amountemitted by the sun. Related to this the actual worldwide primary energy consumptionis less than 0.01%.

Outside the atmosphere electromagnetic radiation from the sun consists ofwavelengths in a range 10�20 to 104m. However, solar radiation is mainly emittedin wavelengths between 0.2 and 5mm. Approximately 90% of the radiation is emittedwith wavelengths between 0.3 and 1.5mm, reaching from the near UV-B to UV-A,visible light, and near-infrared. The sun radiates similarly to a black body with atemperature of approximately 5800K. For most of the radiation the atmosphere ispractically opaque; however, an optical window that is transparent for wavelengths inthe range 0.29–5mm enables radiation with a total power of approximately 1000Wm�2 to pass. While even further diluted while passing through the atmosphere, theaforesaid optical window enables more than 90% of visible light within the solarspectrum to reach earths surface. In the range 0.38–0.78mm visible light representsalmost 50%of the transmitted energy. This range ismost important for the biosphereand also for technical use.

Figure 1.2 gives the spectral distribution of solar radiation outside the atmosphere.The range shown contains approximately 95% of the radiation power of the solarspectrum.

Extraterrestrial solar radiation (outside the atmosphere) is the sole direct radiationcoming from the direction of the sun. Direct solar radiation is characterized by thecapability to cause shadow and the possibility to be concentrated. On entering theatmosphere, part of this direct radiation is reflected (scattered) or absorbed byaerosols, dust, and diverse molecules (e.g., H2O and O3). The measure of extinctionwithin the atmosphere depends on the amount and kinds of particles and the lengthof the path. In this respect and for calculating of the solar irradiation that is availableon earth, the so-called air mass is an important figure. For solar radiation withperpendicular (normal) incidence an air mass of 1 is defined. An air mass of 1.5corresponds to an incidence angle, �Zenith of 48.19 � (Figure 1.3).

Figure 1.1 Geometrical proportions between the sun and the earth.

4j 1 Principles