Planning & Installing Solar Thermal Systems A guide for installers, architects and engineers Fully revised & updated second edition NEW EDITION OF THE BESTSELLING INSTALLATION GUIDE Solar thermal systems available today offer efficiency and reliability. They can be applied in different conditions to meet space- and water-heating requirements in the residential, commercial and industrial building sectors. This fully updated edition of 2004’s bestselling guide offers clear guidance on planning and installing a solar thermal system, crucial to the successful uptake of this technology. All major topics for successful project implementation are included. Beginning with resource assessment and an outline of core components, it details the latest best practice in solar thermal system design, installation, operation and maintenance for single households, large systems, swimming pool heaters, solar air and solar cooling applications. Details on how to market solar thermal technologies, a review of relevant simulation tools and data on selected regional, national and international renewable energy programmes are also provided. This is the definitive source of guidance for professionals who wish to install solar thermal technology and is a highly valued resource for architects, engineers, roofers and anyone undertaking vocational training or with a specialized and practical interest in this field. About the Authors: German Solar Energy Society (DG S) is the German section of the International Solar Energy Society. Energy/Engineering www.earthscan.co.uk 9 781844 077601 ISBN 978-1-84407-760-1 Deutsche Gesellschaft für Sonnenenergie e.V. International Solar Energy Society, German Section DGS 222x297mm spine 18mm Planning & Installing Solar Thermal Systems second edition Planning and Installing Solar Thermal Systems A guide for installers, architects and engineers Second edition A01_PAI_Solar Thermal Systems_Prelims:therimpr.qxd 31/03/2010 16:46 Page i A01_PAI_Solar Thermal Systems_Prelims:therimpr.qxd 31/03/2010 16:46 Page ii Planning and Installing Solar Thermal Systems A guide for installers, architects and engineers Second edition London • Washington, DC A01_PAI_Solar Thermal Systems_Prelims:therimpr.qxd 31/03/2010 16:46 Page iii First published in 2010 by Earthscan Copyright © Deutsche Gesellshaft für Sonnenenergie, 2010 First edition published by James & James (Science Publishers) Ltd in the UK and USA in 2005 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, except as expressly permitted by law, without the prior, written permission of the publisher. While the author and publishers believe that the information and guidance given in this work are correct, all parties must rely upon their own skill and judgement when making use of them – it is not meant to be a replacement for manufacturer’s instructions and legal technical codes. Neither the author nor the publisher assumes any liability for any loss or damage caused by any error or omission in the work. Any and all such liability is disclaimed. This book was written using principally metric units. However, for ease of reference by readers more familiar with imperial units, the publisher has inserted these in the text in brackets after their metric equivalents. Please note that some conversions may have been rounded up or down for the purposes of clarity. Earthscan Ltd Dunstan House, 14a St Cross Street London EC1N 8XA, UK Earthscan LLC 1616 P Street, NW, Washington, DC 20036, USA Earthscan publishes in association with the International Institute for Environment and Development For more information on Earthscan publications, see www.earthscan.co.uk or write to earthinfo@earthscan.co.uk ISBN: 978-1-84407-760-1 Typeset by Saxon Graphics Ltd Cover design by Yvonne Booth A catalogue record for this book is available from the British Library Library of Congress Cataloging-in-Publication Data has been applied for. At Earthscan we strive to minimize our environmental impacts and carbon footprint through reducing waste, recycling and offsetting our CO2 emissions, including those created through publication of this book. For more details of our environmental policy, see www.earthscan.co.uk. This book is printed in the UK by Scotprint, an ISO 14001 accredited company. The paper used is FSC certified and the inks are vegetable based. A01_PAI_Solar Thermal Systems_Prelims:therimpr.qxd 31/03/2010 16:46 Page iv Contents Foreword xi CHAPTER 1: Solar radiation and arguments for its use 1 1.1 Solar radiation 1 1.1.1 Solar energy 1 1.1.2 Astronomical and meteorological bases 1 1.1.3 Influence of orientation and tilt angle 8 1.1.4 Collection of dust and need for cleaning 10 1.2 The finiteness of energy resources 11 1.3 Climate change and its consequences 13 1.4 Good arguments for solar systems 16 CHAPTER 2: Components of solar thermal systems 17 2.1 How does a solar thermal system work? 17 2.2 Collectors 18 2.2.1 Unglazed collectors 21 2.2.2 Glazed flat-plate collectors 21 2.2.3 Vacuum collectors 30 2.2.4 Collector accessories 34 2.2.5 Collector characteristic curves and applications 35 2.2.6 Stagnation temperature 35 2.3 Heat stores 36 2.3.1 Storage materials 36 2.3.2 Domestic hot water stores 37 2.3.3 Buffer store 40 2.3.4 Combination stores 40 2.3.5 The thermostatic mixing valve 46 2.3.6 Connection of washing machines and dishwashers 46 2.3.7 Legionella contamination 46 2.4 Solar circuit 47 2.4.1 Pipelines 47 2.4.2 Solar liquid 48 2.4.3 Solar pumps 50 2.4.4 Solar heat exchanger (heat transfer unit) 51 2.4.5 Return-flow prevention 52 2.4.6 Rapid air bleeders 52 2.4.7 Flowmeters 54 2.4.8 Safety devices in the solar circuit 54 2.4.9 Solar station 55 2.5 Controller 55 2.5.1 Control principles for temperature difference control 59 2.5.2 Digital controller with special functions 59 2.5.3 Temperature sensors 62 2.5.4 Overheating protection 65 CHAPTER 3: Systems for single-family houses 67 3.1 Introduction 67 3.2 Systems for charging/discharging the store 68 3.2.1 Charging by means of solar energy 68 v A01_PAI_Solar Thermal Systems_Prelims:therimpr.qxd 31/03/2010 16:46 Page v 3.2.2 Charging by means of auxiliary heating 69 3.2.3 Store discharge 70 3.3 Systems for heating domestic water 70 3.3.1 Standard system 70 3.3.2 Water heating using the flow-through principle 71 3.3.3 Water heating by means of tank-in-tank store 71 3.3.4 Water heating over external heat exchanger 71 3.3.5 Drain back system 72 3.4 Systems for heating domestic water and space heating 72 3.4.1 Combined store system (store-in-store system) 73 3.4.2 System with buffer store, internal heat exchanger for heat removal and downpipe 73 3.4.3 Stratified store with hot water heating in once-through flow and heating support 73 3.4.4 Twin store system 73 3.5 Planning and dimensioning 74 3.5.1 Important features for preparing the quotation 74 3.5.2 The dimensioning of systems for domestic water heating 77 3.5.3 Dimensioning of systems for heating domestic water and heating support (central European conditions) 89 3.6 Costs and yields 90 3.6.1 Prices and performance 90 3.6.2 Normalised solar heat costs 94 CHAPTER 4: Installation, commissioning, maintenance and servicing 97 4.1 A brief study of roofing and materials 97 4.1.1 The purpose of the roof 97 4.1.2 Types of roof 97 4.1.3 The components of the roof 98 4.1.4 Pitched roofs 103 4.1.5 Roof installations and mountings 103 4.1.6 Flat roofs 103 4.1.7 Materials 103 4.2 Installation methods and safety 107 4.2.1 UK safety regulations 107 4.2.2 UK personal access and working at heights 108 4.2.3 Working equipment 109 4.2.4 Transport techniques 110 4.2.5 Installation techniques 110 4.3 Installation 111 4.3.1 Delivery of material 111 4.3.2 Setting up the site, preparatory work 111 4.3.3 Collector installation 111 4.3.4 Installation of the solar circuit 126 4.3.5 Store installation 128 4.3.6 Installation of fittings 133 4.3.7 Installation of sensors and controllers 136 4.4 Starting up, maintenance and servicing 136 4.4.1 Flushing out the solar circuit 136 4.4.2 Leak testing 137 4.4.3 Filling with solar liquid 137 4.4.4 Setting the pump and controller 138 4.4.5 Maintenance 138 4.4.6 Detecting and rectifying faults 139 vi PLANNING AND INSTALLING SOLAR THERMAL SYSTEMS A guide for installers, architects and engineers A01_PAI_Solar Thermal Systems_Prelims:therimpr.qxd 31/03/2010 16:46 Page vi 4.5 Information sources for specific countries 146 4.5.1 USA 146 4.5.2 Australia 146 4.5.3 Canada 147 CHAPTER 5: Large-scale systems 149 5.1 The fundamentals of designing the system size 149 5.1.1 Possible application areas 149 5.1.2 Initial data required for planning the solar system 149 5.1.3 System planning and design 150 5.2 Systems 153 5.2.1 Systems with domestic water store(s) 153 5.2.2 Systems with thermal buffer stores 154 5.2.3 Integration of circulation systems 156 5.3 Control of the systems 156 5.3.1 Collector circuit/storage charging circuit 156 5.3.2 Buffer tank circuit discharging 161 5.4 Heat exchangers 162 5.4.1 Design types 162 5.4.2 Collector circuit heat exchangers 164 5.4.3 Buffer tank discharge circuit heat exchangers 165 5.5 Safety technology 168 5.5.1 Collector field 168 5.5.2 Collector circuit 169 5.5.3 Buffer store circuit 170 5.5.4 Expansion vessels 171 5.5.5 Fittings on the domestic water line 171 5.6 Economic considerations 172 5.6.1 Annuity method 172 5.6.2 Types of costs for solar energy systems 173 5.7 Solar contracting 174 5.8 Solar district heating 177 5.8.1 Solar energy systems with short-term heat storage 178 5.8.2 Solar systems with long-term heat storage 178 5.8.3 Guide values for the design of solar district heating systems 179 5.8.4 Components of solar district heating systems 179 5.8.5 Practical experience 181 CHAPTER 6: Solar concentrating systems 183 6.1 Concentration of solar radiation 183 6.2 Concentrating systems providing process heat 184 6.3 Concentrating solar thermal systems for electricity generation 189 6.3.1 Parabolic trough plants 189 6.3.2 Solar tower plants 193 6.3.3 Dish/Stirling systems 195 6.3.4 Economics and outlook 196 CHAPTER 7: Solar heating of open-air swimming pools 197 7.1 Introduction 197 7.2 Components 197 7.2.1 Absorbers 197 7.2.2 Piping and header pipes 201 7.2.3 Materials 202 CONTENTS vii A01_PAI_Solar Thermal Systems_Prelims:therimpr.qxd 31/03/2010 16:46 Page vii 7.2.4 Pumps, heat exchangers and other components 202 7.2.5 Controllers 204 7.2.6 Covering of the swimming pool 206 7.3 Systems 206 7.3.1 Solar private open-air pool heating 206 7.3.2 Solar heating of public open-air swimming pools 208 7.3.3 Combined solar domestic water heating, open-air pool heating and room heating support 210 7.4 Planning and dimensioning 211 7.4.1 Fundamental considerations 211 7.4.2 Approximation formulae for establishing absorber surface area, volumetric flow and pressure loss 211 7.4.3 Computer-aided system dimensioning 214 7.5 Installation 214 7.5.1 Absorbers 214 7.5.2 Pipeline installation 217 7.6 Operation and maintenance 219 7.7 Costs and yields 219 7.8 Examples 220 7.8.1 Solar heating of a private swimming pool 220 7.8.2 Solar heating of a municipal open-air pool complex 220 CHAPTER 8: Solar air systems 223 8.1 Introduction 223 8.2 Components 224 8.2.1 Collector types 224 8.2.2 Fans, blowers 229 8.2.3 Piping 230 8.2.4 Heat exchangers and heat recovery units (air/water), recovery- solar-box 230 8.2.5 Control 232 8.3 Systems 234 8.3.1 Central systems, decentralized systems and hybrid systems 234 8.3.2 Further terms of ventilation technology 234 8.3.3 Air collector systems in housing construction 235 8.3.4 Solar drying 239 8.3.5 Factories, halls and office buildings 240 8.4 Planning and dimensioning 242 8.4.1 Fundamental considerations 242 8.4.2 Calculation of required flow rate, required collector surface area and connections of collectors 243 8.4.3 Calculation of fan power 244 8.4.4 Dimensioning of an air-to-water heat exchanger 244 8.4.5 Computer-assisted system sizing 245 8.5 Installation 246 8.5.1 Collector installation 246 8.5.2 Installation of pipelines 248 8.5.3 Positioning of the fan 248 8.6 Costs and yields 248 8.7 Examples 249 8.7.1 Domestic building, Potsdam, Germany 249 8.7.2 Solarwall on General Motors building in Ontario 250 viii PLANNING AND INSTALLING SOLAR THERMAL SYSTEMS A guide for installers, architects and engineers A01_PAI_Solar Thermal Systems_Prelims:therimpr.qxd 31/03/2010 16:46 Page viii CHAPTER 9: Solar cooling 253 9.1 Introduction 253 9.2 Theoretical bases 255 9.2.1 Overview of thermally driven cooling processes 255 9.2.2 Absorption cooling 255 9.2.3 Adsorption cooling 256 9.2.4 Desiccant cooling system 257 9.3 Integrated planning of solar cooling/air-conditioning systems 259 9.4 System technology 262 9.4.1 Autonomous solar-powered systems versus solar-assisted systems 262 9.4.2 Which collector technology for which cooling technology? 263 9.4.3 Circuit variants 264 9.5 System design 268 9.5.1 General procedure when designing systems 269 9.5.2 System design using empirical values 270 9.5.3 System design according to the peak load 270 9.5.4 Design of autonomous solar-powered systems 271 9.5.5 System design according to primary energy saving 271 9.6 More information 273 CHAPTER 10: Electronic media and software within the area of solar thermal energy 275 10.1 Simulation programs for solar thermal systems 275 10.1.1 Utilization and possibilities of simulation programs 275 10.1.2 Market overview, organization and selection of simulation programs 276 10.1.3 Brief description of simulation programs 277 10.1.4 Evaluation of simulation results 289 10.1.5 Supplementary programs and data sources 289 10.1.6 Tools and utility programs 292 10.2 Materials from manufacturers 294 10.2.1 CD-ROMs, documentation, product catalogues 294 10.2.2 Simulation programs from manufacturers 294 10.3 Internet 294 10.3.1 Internet portals on the topic of solar energy 294 10.3.2 Manufacturer websites 294 10.3.3 Internet-based simulation 294 CHAPTER 11: Marketing and promotion 295 11.1 The fundamentals of solar marketing 295 11.1.1 Customer orientation: the central theme 295 11.1.2 The iceberg principle 295 11.1.3 The ‘pull’ concept 296 11.2 More success through systematic marketing 296 11.2.1 In the beginning is the benefit 296 11.2.2 The four pillars of the marketing concept 297 11.2.3 The range of marketing options 301 11.2.4 To the goal in six steps 311 11.3 The Soltherm Europe Initiative: European network of solar thermal marketing campaigns 315 11.3.1 Publications 315 11.3.2 Partnership 316 11.3.3 Campaigns and market activities 316 11.3.4 Co-operation 317 CONTENTS ix A01_PAI_Solar Thermal Systems_Prelims:therimpr.qxd 31/03/2010 16:46 Page ix [...]... 1300 and 1900 hours per year However, the radiation is a far more reliable figure to use when designing or installing solar energy systems M01_PAI _Solar Thermal Systems_ Ch01:ther01.qxd 31/03/2010 12:04 Page 6 6 PLANNING AND INSTALLING SOLAR THERMAL SYSTEMS A guide for installers, architects and engineers Table 1.2 Solar irradiation (kWh/m2 per day) around the world Figure 1.9 Monthly sum of global solar. .. M01_PAI _Solar Thermal Systems_ Ch01:ther01.qxd 31/03/2010 12:04 Page 7 SOLAR RADIATION AND ARGUMENTS FOR ITS USE 7 Figure 1.10 Total annual global radiation (on horizontal surface) Figure 1.10a Europe Figure 1.10b USA Figure 1.10c The world M01_PAI _Solar Thermal Systems_ Ch01:ther01.qxd 31/03/2010 12:04 Page 8 8 PLANNING AND INSTALLING SOLAR THERMAL SYSTEMS A guide for installers, architects and engineers... of practical approaches for successful solar marketing ■ Results of market research giving an overview of the suppliers of solar thermal systems A01_PAI _Solar Thermal Systems_ Prelims:therimpr.qxd 31/03/2010 16:46 Page xii M01_PAI _Solar Thermal Systems_ Ch01:ther01.qxd 31/03/2010 12:04 Page 1 1 1 Solar radiation and arguments for its use 1.1 Solar radiation 1.1.1 Solar energy The most important supplier... M01_PAI _Solar Thermal Systems_ Ch01:ther01.qxd 31/03/2010 12:04 Page 12 12 PLANNING AND INSTALLING SOLAR THERMAL SYSTEMS A guide for installers, architects and engineers THE FORECAST LIFETIME OF OIL AND NATURAL GAS RESERVES OIL The current estimate of secured oil reserves is between 118 and 180 billion tonnes: the latter figure includes so-called non-conventional oil reserves (heavy oils, tar sand, oil... procedures ■ The substitution of non-renewable for renewable energy sources And last but not least ■ Changes in consumer behaviour M01_PAI _Solar Thermal Systems_ Ch01:ther01.qxd 31/03/2010 12:04 Page 16 16 PLANNING AND INSTALLING SOLAR THERMAL SYSTEMS A guide for installers, architects and engineers 1.4 Good arguments for solar systems Every year the number of freshly installed collector surfaces increases,... 2.1 Standard solar water heating system with heating boiler for additional heating (S = temperature sensor) M02_PAI _Solar Thermal Systems_ Ch02:ther02.qxd 31/03/2010 12:05 Page 18 18 PLANNING AND INSTALLING SOLAR THERMAL SYSTEMS A guide for installers, architects and engineers transferred into the lower heat exchanger, where the heat is transferred to the stored domestic water In Australia, Israel and. .. receiving surfaces in (a) Berlin, (b) Vienna and (c) Bern Azimuth angle in Azimuth angle in M01_PAI _Solar Thermal Systems_ Ch01:ther01.qxd 31/03/2010 12:04 Page 10 10 PLANNING AND INSTALLING SOLAR THERMAL SYSTEMS A guide for installers, architects and engineers According to the annual average, optimum irradiance occurs with a southern alignment (α = 0°) and an inclination of β = 30° The graph also shows... irradiation in London Figure 1.4 Irradiation on three different days in Sydney, Australia Figure 1.5 Global solar irradiance and its components M01_PAI _Solar Thermal Systems_ Ch01:ther01.qxd 31/03/2010 12:04 Page 4 4 PLANNING AND INSTALLING SOLAR THERMAL SYSTEMS A guide for installers, architects and engineers When the sun is vertically above a location the sunlight takes the shortest path through the... volumetric flow rate and flow speed 338 C.9 Angles 338 C.10 Surfaces and lengths 338 C.11 System variables 339 C.12 Financing 339 C.13 Constants 339 References and further information 341 Index 343 A01_PAI _Solar Thermal Systems_ Prelims:therimpr.qxd 31/03/2010 16:46 Page xi xi Foreword The market for solar thermal systems is growing rapidly Building owners, planning engineers, architects, fitters and roofers... switched off ■ The solar system makes them less dependent on increases in energy prices ■ Solar system operators enjoy tax advantages and government funding in many countries (see Chapter 11) ■ Solar systems increase both the value of the property and its image Solar houses’ can be sold or rented out more easily ■ Thermal solar systems for the provision of hot water are technically mature and have a service . e.V. International Solar Energy Society, German Section DGS 222x297mm spine 18mm Planning & Installing Solar Thermal Systems second edition Planning and Installing Solar Thermal Systems A guide. AND INSTALLING SOLAR THERMAL SYSTEMS A guide for installers, architects and engineers A01_PAI _Solar Thermal Systems_ Prelims:therimpr.qxd 31/03/2010 16:46 Page x Foreword The market for solar thermal. Detecting and rectifying faults 139 vi PLANNING AND INSTALLING SOLAR THERMAL SYSTEMS A guide for installers, architects and engineers A01_PAI _Solar Thermal Systems_ Prelims:therimpr.qxd 31/03/2010 16:46