Task 39 Handbook is Available Now!

Bridging the gap between basic science and technological applications, this is the first 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 first 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 fields, 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 labs.

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Table of Contents

About the Editors XV

List of Contributors XVII

IEA Solar Heating and Cooling Programme XXI

Acknowledgments XXIII

Part I 1

1 Principles 3
Markus Peter

• 1.1 Introduction 3
• 1.2 Solar Irradiance in Technical Applications 6
• 1.3 Quantifying Useful Solar Irradiation 6
• 1.4 Solar Thermal Applications 7
• 1.5 Calculating the Solar Contribution 10
• 1.6 Conclusions 10

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

• 2.1 Introduction 13
• 2.2 Collector Types 14
• 2.2.1 Unglazed Collectors 14
• 2.2.2 Flat Plate Collectors (FPC) 15
• 2.2.3 Evacuated Flat Plate Collector (EFPC) 16
• 2.2.4 Evacuated Tube Collectors (ETC) 16
• 2.2.5 Concentrating Collectors 16
• 2.2.6 Air Collectors 18
• 2.2.7 Market Share of Different Collector Types 18
• 2.3 Regional Markets 19
• 2.4 Market Trends 22
• 2.4.1 Global Market Development 22
• 2.4.2 Global Market Forecast 25
• 2.4.3 Focus on Europe 25
• Links Providing Updated Market Data and Forecasts 26
• References 26

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

• 3.1 Solar Thermal Systems and Technical Requirements 29
• 3.2 Overview of Solar Thermal Applications 29
• 3.2.1 Swimming Pool Heating Applications 31
• 3.2.2 Domestic Hot Water Preparation for Single Family Houses 33
• 3.2.3 Domestic Hot Water Preparation for Multi-family Houses 39
• 3.2.4 Space Heating and DHW Preparation 40
• 3.2.5 Solar Cooling Applications 44
• 3.2.6 Solar Assisted District Heating 47
• 3.2.7 Process Heat Applications 49
• 3.3 Solar Thermal Collectors 50
• 3.3.1 Basic Principle of a Solar Thermal Collector 50
• 3.3.2 Unglazed Collector 53
• 3.3.3 Glazed Flat Plate Collector 56
• 3.3.4 Evacuated Tubes 58
• 3.3.5 Other Types of Collectors 60
• 3.3.6 Selective Coatings for Solar Absorbers 62
• 3.4 Small to Medium Size Storages 63
• 3.4.1 Classification of Heat Storages 64
• 3.4.2 Domestic Hot Water Storages 65
• 3.4.3 Non-domestic Hot Water Storages 67
• 3.4.4 Non-water Based Storage 68
• 3.5 Sources of Further Information 70
• 3.5.1 Related International Energy Agency Solar Heating and Cooling Tasks 70
• 3.5.2 Web Sites and Projects Related to Solar Thermal Systems 70
• References 70

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

• 4.1 Collectors 73
• 4.1.1 Transparent Covers 75
• 4.1.2 Absorber Plate Risers and Manifolds 75
• 4.1.3 Absorber Coatings 76
• 4.1.4 Thermal Insulation 77
• 4.2 Material Properties of Insulations 79
• 4.2.1 Casing 80
• 4.2.2 Sealing 80
• 4.2.3 Collector Mounting Structures 80
• 4.3 Heat Store 81
• 4.4 Other Components 84
• 4.5 Analysis of Typical Combisystems 86
• 4.5.1 Combisystems Analyzed 86
• 4.5.2 Weight of the Components 86
• 4.5.3 Materials Used in the Systems 86
• 4.5.4 Materials Used in the Components 88
• 4.6 Definition of Polymeric Based Solar Thermal Systems 92
• 4.7 Life Cycle Assessment Based on Cumulated Energy Demand, Energy Payback Time, and Overall Energy Savings 97
• 4.8 Cumulated Energy Demand, Energy Payback Time, and Overall Energy Savings for Conventional and Polymeric Based Domestic Hot Water Systems 98
• 4.8.1 System Boundary 100
• 4.8.2 Cumulative Energy Demand 100
• 4.8.2.1 Cumulative Energy Demand for Production 100
• 4.8.3 Conventional Reference System for the Determination of the Primary Energy Saved by the Solar Thermal System 101
• 4.8.4 Fractional Energy Savings 102
• 4.8.5 Lifetime 102
• 4.8.6 Calculation for Solar Domestic Hot Water Systems 102
• 4.8.6.1 Materials and Masses of the Systems Used for the Reference System (DHW1) 102
• 4.8.6.2 Materials and Masses of the Systems Used for the Polymeric System (DHW2) 102
• 4.8.6.3 Input Values and Results for Determination of the CED 102
• 4.8.6.4 Overall Energy Savings and Energy Payback Time 104
• References 106

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

• 5.1 Introduction 107
• 5.2 Results of Monitoring Temperature Loads 107
• 5.3 Measures for Reduction of the Temperature Loads 114
• References 117

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

• 6.1 Introduction 119
• 6.2 Collectors 119
• 6.2.1 Testing of Solar Collectors for Durability and Reliability 120
• 6.2.2 Testing of Solar Collectors for Thermal Performance 120
• 6.3 Solar Thermal Systems 121
• 6.3.1 Testing of Solar Thermal Products 124
• 6.3.1.1 CSTG Method 125
• 6.3.1.2 DST Method 125
• 6.3.2 CTSS Method 125
• 6.4 Conclusion 125
• Part II 127

7 Plastics Market 129
Katharina Resch and Gernot M. Wallner

• References 134

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

• 8.1 Introduction 135
• 8.2 Material Structure and Morphology of Polymers 136
• 8.3 Inner Mobility and Thermal Transitions of Polymers 143
• 8.4 Polymer Additives and Compounds 146
• 8.4.1 Stabilizing Additives 147
• 8.4.2 Antioxidants 147
• 8.4.3 Light Stabilizers 148
• 8.4.4 Modifying Additives 148
• References 149

9 Processing 151

• 9.1 Structural Polymeric Materials 151
• Helmut Vogel
• 9.1.1 Introduction to Polymer Processing 151
• 9.1.2 Extrusion Based Processes 152
• 9.1.2.1 Profile Extrusion 152
• 9.1.2.2 Film Blowing 154
• 9.1.2.2.1 Cast Film Extrusion 154
• 9.1.2.3 Calender Stack Process for Plates 155
• 9.1.2.4 Blow Molding 157
• 9.1.2.4.1 Extrusion Blow Molding 159
• 9.1.2.4.2 Injection Blow Molding 160
• 9.1.3 Injection Molding 161
• 9.1.3.1 Injection Molding Cycle 162
• 9.1.4 Thermoforming 164
• 9.1.5 Fiber Reinforced Polymer 165
• 9.1.5.1 Sheet Molding Compound (SMC) 165
• 9.1.5.2 Glass Mat Thermoplastics (GMT) 165
• References 166
• 9.2 Paint Coatings for Polymeric Solar Absorbers and Their Applications 167
• Ivan Jerman, Matja
  z Ko
  zelj, Lidija Slemenik Per4se, and Boris Orel
• 9.2.1 Outline of Content 167
• 9.2.2 General Remarks about Selective Paint Coatings 168
• 9.2.3 Preparation of Selective Paints 169
• 9.2.3.1 Effect of Dispersants on Pigment Dispersions 170
• 9.2.3.2 Dispersants 171
• 9.2.3.3 Trisilanol T7 POSS Dispersants for Colored TISS Paint Coatings 174
• 9.2.4 Application Techniques for Spectrally Selective Paints 175
• 9.2.4.1 Brush and Hand Roller Application 175
• 9.2.4.2 Spray Application 176
• 9.2.4.3 Case Study: Application of TISS Paint on a Polymeric Substrate by Using Simple Silane Dispersants 178
• 9.2.4.4 Direct Coating Application Techniques 179
• 9.2.4.5 Dip Coating 180
• 9.2.4.6 Dip and Flow Coating 180
• 9.2.4.7 Roll Coating 182
• 9.2.4.8 Coil Coating 182
• 9.2.5 Conclusions 185
• References 185

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

• 10.1 Introduction 187
• 10.2 Polymeric Glazing 188
• 10.3 Polymeric Absorbers and Heat Exchangers 189
• 10.3.1 Overview of Relevant Polymer Material Properties and Requirements 191
• 10.3.2 Additional Material Considerations 196
• 10.3.2.1 Fillers to Improve Thermal Conductivity and Strength 196
• 10.3.2.2 Scaling 198
• 10.3.2.3 Oxidation 199
• 10.3.3 Absorbers 201
• 10.3.3.1 Material Selection 201
• 10.3.3.2 Polymer Absorber Applications 203
• 10.3.4 Heat Exchangers 204
• 10.3.4.1 Material Selection 205
• 10.3.4.2 Polymer Heat Exchanger Applications 205
• 10.4 Conclusion 206
• References 207

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

• 11.1 Introduction 211
• 11.2 How to Select the Right Material 211
• 11.3 Material Databases 212
• 11.4 Selection Criteria 213
• 11.5 Real Life Example: Standard Collector in Plastic (1:1 Substitution) 213
• 11.5.1 Preselection 214
• 11.5.1.1 Housing 215
• 11.5.1.2 Absorber 216
• 11.5.1.3 Sealing 217
• 11.5.1.4 Glazing 217
• 11.5.1.5 Insulation 217
• 11.6 Summary 218

Part III 219

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

• 12.1 Solar Collectors 221
• 12.1.1 Pool Absorbers 221
• 12.1.2 Material Substitution in Conventional Collector Designs 222
• 12.1.3 Glazed Flat-Plate Collectors with Polymeric Absorbers 224
• 12.1.4 Air Collector Systems 224
• 12.1.5 Integrated Storage Collectors and Thermosiphon Systems 225
• 12.1.6 Collector Glazing 227
• 12.1.7 Integrated and Multifunctional Applications 228
• 12.1.8 Absorber Designs from a Polymer Engineering Point of View 229
• 12.1.9 Summary 231
• 12.2 Small to Mid-Sized Polymeric Heat Stores 231
• 12.2.1 Introduction 231
• 12.2.2 Challenges 235
• 12.3 Polymeric Liners for Seasonal Thermal Energy Stores 235
• 12.3.1 Envelope Design of Thermal Energy Stores 236
• 12.3.2 Liner of Pilot and Research Thermal Energy Stores 237
• 12.3.3 Summary 239
• References 241

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

• 13.1.1 Introduction and Scope 243
• 13.1.2 Methodology 244
• 13.1.3 Results, Discussion, and Outlook 246
• 13.1.3.1 Characterization of Physical and Chemical Aging of Polymeric Solar Materials by Mechanical Testing 246
• 13.1.3.2 Aging Behavior of Polymeric Solar Absorber Materials – Part 1: Engineering Plastics 247
• 13.1.3.3 Aging Behavior of Polymeric Solar Absorber Materials – Part 2: Commodity Plastics 248
• 13.1.3.4 Aging Behavior and Lifetime Modeling for Polymeric Solar Absorber Materials 249
• 13.1.3.5 Aging Behavior of Polymeric Solar Absorber Materials: Aging on Component Level 250
• References 252
• 13.2 Thermotropic Layers for Overheating Protection of all-Polymeric Flat Plate Solar Collectors 255
• Katharina Resch, Robert Hausner, Gernot M. Wallner, and Reinhold W. Lang
• 13.2.1 Introduction 255
• 13.2.2 Materials and Sample Preparation 256
• 13.2.3 Physical Characterization of the Polymers 257
• 13.2.4 Results and Discussion 258
• 13.2.5 Effect of Thermotropic Layers on Collector Efficiency and Stagnation Temperatures 262
• 13.2.6 Outlook 263
• References 264
• 13.3 Application of POSS Compounds for Modification of the Wetting Properties of TISS Paint Coatings 267
• Ivan Jerman, Boris Orel, and Matja
  z Ko
  zelj
• 13.3.1 Introduction 267
• 13.3.2 Wetting of Surfaces 270
• 13.3.2.1 Basic Principles – Learning from Nature 270
• 13.3.2.2 Surface Energy 272
• 13.3.2.3 Surface Roughness 273
• 13.3.2.4 Morphology of TISS Paint Coatings 275
• 13.3.3 POSS Nanocomposites as Low Surface Energy Additives for Coatings 276
• 13.3.3.1 Synthesis and Structural Characteristics of POSS Molecules 276
• 13.3.4 Anti-wetting Properties of Coatings with Smooth Surfaces – Lacquers for Polymeric Glazing 278
• 13.3.4.1 Structure of Fluoropolymer Resin Binders – General Remarks 279
• 13.3.4.2 Contact Angles and Surface Properties of Lumiflon Resin Binders 280
• 13.3.4.3 Interaction of POSS – SEM Micrographs and Optical Transmission 281
• 13.3.5 Anti-wetting Properties of Coatings on Rough Surfaces – TISS Paint Coatings 282
• 13.3.5.1 Wetting Properties of TISS Coatings 282
• 13.3.6 Conclusions 284
• References 284

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

• 14.1 Introduction 287
• 14.2 Calculation of Collector Efficiency 287
• 14.3 Flow Optimization 291
• 14.4 Optimization of the Fluid Dynamics in Polymeric Collectors 291
• 14.4.1 Optimization of the Absorber 291
• 14.4.2 Optimization of the Fluid Dynamics in the Header 292
• 14.4.3 Optimization of the Fluid Dynamics Non-rectangular Collectors 292
• 14.5 Collector Mechanics 295
• 14.6 Conclusion 297
• References 299

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

• 15.1 Introduction 301
• 15.2 Solar Absorber Made of High-Performance Plastics 301
• 15.2.1 General Presentation 301
• 15.2.2 Detailed Description 302
• 15.2.3 Experiences with Development of the Products 307
• 15.3 Flate Plate Collector with Overheating Protection 307
• 15.3.1 General Presentation 307
• 15.3.2 Detailed Description 307
• 15.3.3 Experience Gained with Development of the Products 309
• 15.4 Flat Plate Collectors with a Thermotropic Layer 310
• 15.4.1 General Presentation 310
• 15.4.2 Detailed Description 310
• 15.4.3 Experience Gained with Development of the Products 313
• 15.5 Solar Storage Tank with Polymeric Sealing Technology with Storage Volumes from 2 to 100 m3 313
• 15.5.1 General Presentation 313
• 15.5.2 Detailed Description 314
• 15.5.3 Experience Gained with Development of the Products 314
• References 317

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

• 16.1 Introduction 319
• 16.2 Twenty Years Outdoor Weathering of Polymeric Materials for use as Collector Glazing 320
• 16.2.1 Introduction 320
• 16.2.2 Material Selection 320
• 16.2.3 Exposure 321
• 16.2.4 Evaluation of Optical Properties 322
• 16.2.5 Results 323
• 16.2.5.1 PMMA 323
• 16.2.5.2 PC 325
• 16.2.5.3 Fluoropolymers 326
• 16.2.5.4 UP 329
• 16.2.5.5 PET and PVC 330
• 16.2.6 Conclusion 330
• 16.3 Accelerated Lifetime Testing of a Polymeric Absorber Coating 332
• 16.3.1 Introduction 332
• 16.3.2 Application of the ALT Test Procedure on the TISS Painted Absorber 333
• 16.3.3 Adaption of the ALT Procedure to the TISS Painted Absorber 333
• 16.3.4 Conclusions 337
• 16.4 Evaluation of Temperature Resistance of a Polymer Absorber in a Solar Collector 337
• 16.4.1 Background 337
• 16.4.2 Method 338
• 16.4.3 Experiments 339
• 16.4.4 Service Life for a Plastics Absorber Made in PPS 341
• 16.4.5 Conclusion 343
• 16.5 Determination of Water Vapor Transport through Polymeric Materials at Raised Temperatures 343
• 16.5.1 Measurement Setup/Testing Rig 344
• 16.5.2 Results 346
• 16.5.3 Conclusion 347
• References 347

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

• 17.1 Introduction 351
• 17.2 Architectural Integration as a Marketing Tool 351
• 17.3 Web Database 353
• 17.4 Examples 354
• References 357

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

• 18.1 Introduction 359
• 18.2 Internal Absorber Pressure Test 359
• 18.2.1 Description of the Specific Test and Test Procedure 359
• 18.2.2 Why this is a Problem for Polymeric Collectors or Why this Test Does not Reflect the Requirements for Polymeric Collectors 360
• 18.2.3 Possible Alternative Procedure 360
• 18.3 High-Temperature Resistance and Exposure Tests 360
• 18.3.1 Description of the Specific Test and Test Procedure 360
• 18.3.2 Why this is a Problem for Polymeric Collectors or Why this Test does not Reflect the Requirements for Polymeric Collectors 361
• 18.3.3 Possible Alternative Procedure 361
• 18.3.3.1 General Comments 361
• 18.3.3.2 Comments on Overheating Protection 362
• 18.3.3.3 Passive Devices 362
• 18.3.3.4 Active Devices 363
• 18.4 Mechanical Load Test 363
• 18.4.1 Description of the Specific Test and Test Procedure 363
• 18.4.2 Why this is a Problem for Polymeric Collectors or Why this Test does not Reflect the Requirements for Polymeric Collectors 364
• 18.4.2.1 Typical Data for Snow Load (According to EN12975 and to PV Norms such as EN61646 etc.) 364
• 18.4.2.2 Typical Data for Wind Load (According to EN12975 and to PV Norms such as EN61646 etc.) 364
• 18.4.2.3 Typical Normative Requirements 364
• 18.4.3 Possible Alternative Procedure 365
• 18.5 Impact Resistance Test 365
• 18.5.1 Description of the Specific Test and Test Procedure 365
• 18.5.2 Why this is a Problem for Polymeric Collectors or Why this Test does not Reflect the Requirements for Polymeric Collectors 365
• 18.5.2.1 Typical Data for Steel Ball Test of 150 g (According to EN12975) 366
• 18.5.2.2 Typical Data for Ice Stones Test of Different Sizes (According to EN12975 and to PV Norms such as EN61646 etc.) 366
• 18.5.2.3 Typical Normative Requirements 366
• 18.5.3 Possible Alternative Procedure 366
• 18.6 Discontinuous Efficiency Curves 366
• 18.6.1 Description of the Specific Test and Test Procedure 366
• 18.6.2 Problems Regarding Polymeric Collectors 367
• 18.6.2.1 The Limit is Dependent Mainly on the Absorber Temperature 367
• 18.6.2.2 The Limit is Dependent on the Absorber Temperature and on the Ambient Temperature 367
• 18.6.3 Possible Alternative Procedures 368
• 18.6.3.1 Determination of the Validity Limit for the Standard Procedures 368
• 18.6.3.2 Determination of Stagnation Temperature 369
• Reference 370

Glossary 371

Polymeric Materials 371

Abbreviations 371

Terms and Definitions 372

Solar Thermal Systems 379

Abbreviations 379

Terms and Definitions 379

Index 385