Solar and Heat Pump Systems for Residential Buildings E-Book

• Herausgeber: Wiley-VCH
• Kategorie: Wissenschaft und neue Technologien
• Serie: Solar Heating and Cooling
• Sprache: Englisch

Seitenzahl: 452

Veröffentlichungsjahr: 2015

Beschreibung

Die Kombination von Wärmepumpen und Solarthermie ist eine relativ neue Entwicklung und hat großes Potenzial, die Energieeffizienz von Heizungs- und Warmwasseranlagen wesentlich zu erhöhen. Damit kann die Gesamtenergiebilanz eines Gebäudes entscheidend verbessert werden. Das Buch ist ein Leitfaden für Entwurf, Simulation, Monitoring und Evaluation von Systemen aus Wärmepumpen und Solarthermie. Verschiedene Systeme werden verglichen und hinsichtlich ihrer Leistungsfähigkeit analysiert. Ergebnisse von Simulationen und Labortests werden ebenso beschrieben wie die Erfahrungen aus gebauten Projekten. Somit ermöglicht es dem Leser, entsprechend der jeweiligen Randbedingungen seines Projektes das effizienteste System zu entwerfen. Dieses Buch ist das erste, das sich eingehend mit dieser Kombination von Komponenten befasst und präsentiert den aktuellen Stand der Technik in diesem Bereich. Es basiert auf einem vierjährigen gemeinsamen Forschungsprojekt zweier Programme der Internationalen Energieagentur: 'Solar Heating and Cooling' (SHC) und 'Heat Pump'. Mehr als 50 renommierte Experten aus 13 Ländern waren an dem Projekt beteiligt.

Leseprobe

CONTENTS

Cover

Related Titles

Title Page

Copyright

About the Editor and the Supervisors

List of Contributors

IEA Solar Heating and Cooling Programme

Forewords

Acknowledgments

Chapter 1: Introduction

1.1 The Scope

1.2 Who Should Read This Book?

1.3 Why This Book?

1.4 What You Will Learn Reading This Book?

Internet Sources

Part One: Theoretical Considerations

Chapter 2: System Description, Categorization, and Comparison

2.1 System Analysis and Categorization

2.2 Statistical Analysis of Market-Available Solar Thermal and Heat Pump Systems

2.3 Conclusions and Outlook

2.4 Relevance and Market Penetration – Illustrated with the Example of Germany

References

Chapter 3: Components and Thermodynamic Aspects

3.1 Solar Collectors

3.2 Heat Pumps

3.3 Ground Heat Exchangers

3.4 Storage

3.5 Special Aspects of Combined Solar and Heat Pump Systems

References

Chapter 4: Performance and its Assessment

4.1 Introduction

4.2 Definition of Performance Figures

4.3 Reference System and System Boundaries

4.4 Environmental Evaluation of SHP Systems

4.5 Calculation Example

Appendix 4.A Reviewed Standards and Other Normative Documents

References

Chapter 5: Laboratory Test Procedures for Solar and Heat Pump Systems

5.1 Introduction

5.2 Component Testing and Whole System Testing

5.3 Experience from Laboratory Testing

5.4 Summary and Findings

References

Part Two: Practical Considerations

Chapter 6: Monitoring

6.1 Background

6.2 Monitoring Technique

6.3 Solar and Heat Pump Performance – Results from Field Tests

6.4 Best Practice Examples

References

Chapter 7: System Simulations

7.1 Parallel Solar and Heat Pump Systems

7.2 Series and Dual-Source Concepts

7.3 Special Collector Designs in Series Systems

7.4 Solar Thermal Savings Versus Photovoltaic Electricity Production

7.5 Comparison of Simulation Results with Similar Boundary Conditions

7.6 Conclusions

Appendix 7.A Appendix on Simulation Boundary Conditions and Platform Independence

Acknowledgment

References

Chapter 8: Economic and Market Issues

8.1 Introduction

8.2 Advantages of SHP Systems

8.3 The Economic Calculation Framework

8.4 A Nomograph for Economic Analysis Purposes

8.5 Application to Real Case Studies

References

Chapter 9: Conclusion and outlook

9.1 Introduction

9.2 Components, Systems, Performance Figures, and Laboratory Testing

9.3 Monitoring and Simulation Results and Nontechnical Aspects

9.4 Outlook

Glossary

Index

EULA

List of Tables

Table 2.1

Table 3.1

Table 3.2

Table 3.3

Table 3.4

Table 3.5

Table 3.6

Table 4.1

Table 4.2

Table 4.3

Table 4.A.1

Table 4.A.2

Table 5.1

Table 5.2

Table 5.3

Table 5.4

Table 5.5

Table 5.6

Table 6.1

Table 7.1

Table 7.2

Table 7.3

Table 7.4

Table 7.5

List of Illustrations

Fig. 2.1

Fig. 2.2

Fig. 2.3

Fig. 2.4

Fig. 2.5

Fig. 2.6

Fig. 2.7

Fig. 2.8

Fig. 2.9

Fig. 2.10

Fig. 3.1

Fig. 3.2

Fig. 3.3

Fig. 3.4

Fig. 3.5

Fig. 3.6

Fig. 3.7

Fig. 3.8

Fig. 3.9

Fig. 3.10

Fig. 3.11

Fig. 4.1

Fig. 4.2

Fig. 4.3

Fig. 4.4

Fig. 4.5

Fig. 4.6

Fig. 4.7

Fig. 4.8

Fig. 4.9

Fig. 4.10

Fig. 4.11

Fig. 4.12

Fig. 5.1

Fig. 5.2

Fig. 5.3

Fig. 5.4

Fig. 5.5

Fig. 5.6

Fig. 5.7

Fig. 5.8

Fig. 5.9

Fig. 6.1

Fig. 6.2

Fig. 6.3

Fig. 6.4

Fig. 6.5

Fig. 6.6

Fig. 6.7

Fig. 6.8

Fig. 6.9

Fig. 6.10

Fig. 6.11

Fig. 6.12

Fig. 6.13

Fig. 6.14

Fig. 6.15

Fig. 6.16

Fig. 6.17

Fig. 6.18

Fig. 7.1

Fig. 7.2

Fig. 7.3

Fig. 7.4

Fig. 7.5

Fig. 7.6

Fig. 7.7

Fig. 7.8

Fig. 7.9

Fig. 7.10

Fig. 7.11

Fig. 7.12

Fig. 7.13

Fig. 7.14

Fig. 7.15

Fig. 7.16

Fig. 7.17

Fig. 7.18

Fig. 7.19

Fig. 7.20

Fig. 7.21

Fig. 7.22

Fig. 7.23

Fig. 7.24

Fig. 7.25

Fig. 7.26

Fig. 8.1

Fig. 8.2

Fig. 8.3

Fig. 8.4

Fig. 8.5

Fig. 8.6

Fig. 8.7

Fig. 8.8

Fig. 8.9

Fig. 8.10

Fig. 8.11

Fig. 8.12

Fig. 8.13

Fig. 8.14

Fig. 8.15

Fig. 8.16

Fig. 9.1

Guide

Cover

Table of Contents

Begin Reading

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Solar and Heat Pump Systems for Residential Buildings

Edited by

Jean-Christophe Hadorn

All books published by Ernst & Sohn are carefully produced. Nevertheless, authors, editors, and publisher do not warrant the information contained in these books, including this book, to be free of errors. Readers are advised to keep in mind that statements, data, illustrations, procedural details or other items may inadvertently be inaccurate.

Library of Congress Card No.: applied for

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

Bibliographic information published by the Deutsche NationalbibliothekThe Deutsche Nationalbibliothek lists this publication in the Deutsche Nationalbibliografie; detailed bibliographic data are available on the Internet at <http://dnb.d-nb.de>.

© 2015 Wilhelm Ernst & Sohn, Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Rotherstraße 21, 10245 Berlin, Germany

All rights reserved (including those of translation into other languages). No part of this book may be reproduced in any form – by photoprinting, microfilm, or any other means – nor transmitted or translated into a machine language without written permission from the publishers. Registered names, trademarks, etc. used in this book, even when not specifically marked as such, are not to be considered unprotected by law.

Print ISBN: 978-3-433-03040-0

ePDF ISBN: 978-3-433-60484-7

ePub ISBN: 978-3-433-60485-4

Mobi ISBN: 978-3-433-60482-3

oBook ISBN: 978-3-433-60483-0

About the Editor and the Supervisors

Editor

Jean-Christophe Hadorn started his career as a researcher on large-scale storage of solar heat in deep aquifers (1979–1981). Since several years, Mr. Hadorn has been appointed as External Manager of Thermal Solar Energy and Heat Storage Research Program by the Swiss government. Mr. Hadorn was a participant in IEA SHC Task 7 on “Central Solar Heating Plants with Seasonal Storage” (1981–1985) and initiated Task 26 on “Solar Combisystems” (1996–2000). He was Operating Agent of Task 32 on “Heat Storage” (2003–2007). Since 2000, he leads an engineering company and designs solar thermal and PV plants. In 2010, he was chosen by an international committee of the IEA as the Operating Agent for the IEA SHC Task 44 “Solar and Heat Pump Systems” also supported by the Heat Pump Programme under Annex 38, project that produced this book.

Supervisors

Dr. Matteo D'Antoni is a senior researcher working at the Institute for Renewable Energy of the European Academy of Bolzano (EURAC) in Italy. He is active in the development of hybrid renewable energy systems for residential and commercial applications and in the design of building integrated solar thermal technologies. He is an expert in numerical calculus and transient simulation of energy systems. He managed EU funded and industry commissioned projects. Dr. D'Antoni lectures designers on the topic of renewable energy sources and energy system simulations.

Dr. Michel Y. Haller is Head of Research at the Institut für Solartechnik SPF at the University of Applied Sciences HSR in Switzerland. He holds a title of Master in Environmental Sciences of ETH Zürich, and obtained his doctoral degree in engineering at Graz University of Technology. He is coordinator of the EU project MacSheep, and author of more than 50 refereed papers. Dr. Haller was leader of the Subtask C “Modelling and Simulation” of the IEA SHC Task 44/HPP Annex 38 on “Solar and Heat Pump Systems.”

Sebastian Herkel is a senior researcher at the Fraunhofer Institute for Solar Energy Systems ISE in Freiburg, Germany and Head of Solar Buildings Department. He is a researcher working in applied research in building energy performance and renewable energy systems. His focus is on integral energy concepts for buildings and neighborhoods, scientific analysis of building performance, and technologies for integration of renewable energy in buildings.

Ivan Malenkovi is a researcher at the Fraunhofer Institute for Solar Energy Systems ISE with over 10 years of experience in R&D, testing, and standardization in the field of heat pumping technologies. He is currently responsible for the ServiceLab for performance evaluation within the Competence Centre for Heat Pumps and Chillers at ISE. He participated in a number of IEA SHC and HPP Tasks and Annexes and was a subtask leader in IEA SHC Task 44/HPP Annex 38. He is author and co-author of a number of articles published in conference proceedings and reviewed journals.

Christian Schmidt is a researcher at the TestLab Solar Thermal Systems at Fraunhofer Institute for Solar Energy Systems ISE (2009–2014). Currently, he is pursuing a Ph.D. project that deals with the further development of performance test methods for multivalent heat transformers used for heating and cooling of buildings. He completed his Masters of Science in Renewable Energy and Energy Efficiency at University of Kassel in 2010. In 2008, he received his Diploma in Mechanical Engineering from Fachhochschule Bingen, University of Applied Sciences.

Wolfram Sparber is Head of the Institute for Renewable Energy at EURAC Research since its foundation in 2005. One of the main research areas of the Institute are sustainable heating and cooling systems with several projects brought forward in the field of solar thermal systems combined with thermally or electrically driven heat pumps.

Since 2011, Wolfram Sparber is Vice President of the board of the European Technology Platform Renewable Heating and Cooling with a focus on hybrid systems including several heat sources in one system. As well in 2011 he took over the presidency of the board of SEL AG, a regional energy utility focused on renewable power production, energy distribution, and district heating.

In the recent years, Wolfram Sparber contributed to the elaboration of several strategic research and technology development documents and was invited as Visiting Professor to different universities. Wolfram Sparber studied applied physics at Graz University of Technology (Austria) and Universitat Autonoma de Barcelona (Spain). He concluded his studies at the Fraunhofer Institute for Solar Energy Systems ISE, Freiburg, Germany.

List of Contributors

Thomas Afjei

Fachhochschule Nordwestschweiz (FHNW)

Institut Energie am Bau (IEBau)

St. Jakobs-Strasse 84

4132 Muttenz

Switzerland

Chris Bales

Solar Energy Research Center (SERC) School of Industrial Technology and Business Studies

Högskolan Dalarna

791 88 Falun

Sweden

Erik Bertram

Institut für Solarenergieforschung Hameln (ISFH)

Am Ohrberg 1

31860 Emmerthal

Germany

Sebastian Bonk

University of Stuttgart

Institute for Thermodynamics and Thermal Engineering (ITW)

Pfaffenwaldring 6

70550 Stuttgart

Germany

Jacques Bony

Haute Ecole d'Ingénierie et de Gestion du Canton de Vaud

Laboratoire d'Energétique Solaire et de Physique du Bâtiment (LESBAT)

Centre St-Roch

av. des Sports 20

1400 Yverdon-les-Bains

Switzerland

Sunliang Cao

Aalto University

School of Engineering

Department of Energy Technology

HVAC Technology

00076 Aalto

Finland

Daniel Carbonell

Hochschule für Technik HSR

Institut für Solartechnik SPF

Oberseestr. 10

8640 Rapperswil

Switzerland

Maria João Carvalho

Laboratório Nacional de Energia e Geologia, I.P.

Laboratório de Energia Solar

Estrada do Paco do Lumiar 22

1649-038 Lisbon

Portugal

Matteo D'Antoni

EURAC Research

Institute for Renewable Energy

Viale Druso 1

39100 Bolzano

Italy

Ralf Dott

Fachhochschule Nordwestschweiz (FHNW)

Institut Energie am Bau (IEBau)

St. Jakobs-Strasse 84

4132 Muttenz

Switzerland

Harald Drück

University of Stuttgart

Institute for Thermodynamics and Thermal Engineering (ITW)

Pfaffenwaldring 6

70550 Stuttgart

Germany

Sara Eicher

Haute Ecole d'Ingénierie et de Gestion du Canton de Vaud

Laboratoire d'Energétique Solaire et de Physique du Bâtiment (LESBAT)

Centre St-Roch

av. des Sports 20

1400 Yverdon-les-Bains

Switzerland

Jorge Facão

Laboratório Nacional de Energia e Geologia, I.P.

Laboratório de Energia Solar

Estrada do Paco do Lumiar 22

1649-038 Lisbon

Portugal

Roberto Fedrizzi

EURAC Research

Institute for Renewable Energy

Viale Druso 1

39100 Bolzano

Italy

Carolina de Sousa Fraga

University of Geneva

Institute for Environmental Sciences

Energy Group

Batelle Bat. D, Route de Drize 7

1227 Carouge

Switzerland

Robert Haberl

Hochschule für Technik HSR

Institut für Solartechnik SPF

Oberseestr. 10

8640 Rapperswil

Switzerland

Jean-Christophe Hadorn

BASE Consultants SA

8 rue du Nant

1207 Geneva

Switzerland

Michel Y. Haller

Hochschule für Technik HSR

Institut für Solartechnik SPF

Oberseestr. 10

8640 Rapperswil

Switzerland

Michael Hartl

AIT Austrian Institute of Technology

Energy Department

Giefinggasse 2

1210 Vienna

Austria

Andreas Heinz

Technische Universität Graz

Institut für Wärmetechnik (IWT)

Inffeldgasse 25/B

8010 Graz

Austria

Sebastian Herkel

Fraunhofer Institute for Solar Energy Systems

Division of Thermal Systems and Buildings

Heidenhofstr. 2

79110 Freiburg

Germany

Pierre Hollmuller

University of Geneva

Institute for Environmental Sciences

Energy Group

Batelle Bat. D, Route de Drize 7

1227 Carouge

Switzerland

Anja Loose

University of Stuttgart

Institute for Thermodynamics and Thermal Engineering (ITW)

Pfaffenwaldring 6

70550 Stuttgart

Germany

Ivan Malenkovic

Fraunhofer Institute for Solar Energy Systems

Division of Thermal Systems and Buildings

Heidenhofstr. 2

79110 Freiburg

Germany

and

AIT Austrian Institute of Technology

Energy Department

Giefinggasse 2

1210 Vienna

Austria

Floriane Mermoud

University of Geneva

Institute for Environmental Sciences

Energy Group

Batelle Bat. D, Route de Drize 7

1227 Carouge

Switzerland

Marek Miara

Fraunhofer Institute for Solar Energy Systems

Division of Thermal Systems and Buildings

Heidenhofstr. 2

79110 Freiburg

Germany

Fabian Ochs

University of Innsbruck

Unit for Energy Efficient Buildings

Technikerstrasse 13

6020 Innsbruck

Austria

Peter Pärisch

Institut für Solarenergieforschung Hameln (ISFH)

Am Ohrberg 1

31860 Emmerthal

Germany

Bengt Perers

Technical University of Denmark

DTU Civil Engineering DK & SERC Sweden

Brovej, Building 118

2800 Kgs. Lyngby

Denmark

Jörn Ruschenburg

Fraunhofer Institute for Solar Energy Systems

Division of Thermal Systems and Buildings

Heidenhofstr. 2

79110 Freiburg

Germany

Christian Schmidt

Fraunhofer Institute for Solar Energy Systems

Division of Thermal Systems and Buildings

Heidenhofstr. 2

79110 Freiburg

Germany

Kai Siren

Aalto University

School of Engineering

Department of Energy Technology

HVAC Technology

00076 Aalto

Finland

Wolfram Sparber

EURAC Research

Institute for Renewable Energy

Viale Druso 1

39100 Bolzano

Italy

Bernard Thissen

Energie Solaire SA

Rue des Sablons 8

3960 Sierre

Switzerland

Alexander Thür

Universität Innsbruck

Institut für Konstruktion und Materialwissenschaften

AB Enrgieeffizientes Bauen

Technikerstr. 19a

6020 Innsbruck

Austria

Martin Vukits

AEE – Institut für Nachhaltige Technologien

Feldgasse 19

8200 Gleisdorf

Austria

IEA Solar Heating and Cooling Programme

The Solar Heating and Cooling Programme was founded in 1977 as one of the first multilateral technology initiatives (“Implementing Agreements”) of the International Energy Agency. Its mission is to “advance international collaborative efforts for solar energy to reach the goal set in the vision of contributing 50% of the low temperature 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, and demonstration (RD&D) and test methods for solar thermal energy and solar buildings.

A total of 53 such projects have been initiated to date, 39 of which have been completed. Research topics include

– Solar Space Heating and Water Heating (Tasks 14, 19, 26, and 44)

– Solar Cooling (Tasks 25, 38, 48, and 53)

– Solar Heat or Industrial or Agricultural Processes (Tasks 29, 33, and 49)

– Solar District Heating (Tasks 7 and 45)

– Solar Buildings/Architecture/Urban Planning (Tasks 8, 11, 12, 13, 20, 22, 23, 28, 37, 40, 41, 47, 51, and 52)

– Solar Thermal & PV (Tasks 16 and 35)

– Daylighting/Lighting (Tasks 21, 31, and 50)

– Materials/Components for Solar Heating and Cooling (Tasks 2, 3, 6, 10, 18, 27, and 39)

– Standards, Certification, and Test Methods (Tasks 14, 24, 34, and 43)

– Resource Assessment (Tasks 1, 4, 5, 9, 17, 36, and 46)

– Storage of Solar Heat (Tasks 7, 32, and 42)

In addition to the project work, a number of special activities – Memorandum of Understanding with solar thermal trade organizations, statistics collection and analysis, conferences, and workshops – have been undertaken. An annual international conference on Solar Heating and Cooling for Buildings and Industry was launched in 2012. The first of these conferences, SHC2012, was held in San Francisco, CA.

Current members of the IEA SHC programme

Australia

Austria

Belgium

Canada

China

Denmark

ECREEE

European Commission

European Copper Institute

Germany

Gulf Organization for Research and Development

France

Italy

Mexico

Norway

Portugal

RCREEE

Singapore

South Africa

Spain

Sweden

Switzerland

The Netherlands

Turkey

United Kingdom

Further Information

For up-to-date information on the IEA SHC work, including many free publications, please visit www.iea-shc.org.

Forewords

The steady growth of solar thermal systems for more than three decades has shown that solar heating systems are both mature and technically reliable. However, solar thermal systems have usually been sold as an add-on to a conventional hot water or space heating system.

In future, we need to develop hybrid systems that offer a complete heating system based on renewables, one that is able to cover 100% of the heating demand of buildings.

One very promising possibility is the combination of solar systems and heat pumps.

This book shows different ways in which these two technologies can be combined, and it presents the path to high-performance hybrid systems.

The book is the result of a collaborative international work within the Solar Heating and Cooling Programme and the Heat Pump Programme of the International Energy Agency (IEA). It is a great pleasure for me, as a former chairman of the IEA SHC Executive Committee, to introduce this book.

The international work has led to some interesting findings on solar and heat pump combinations based on monitored data and the use of simulation. The book presents all these findings and the methodologies needed to assess the energy performance of such combinations. It is an important contribution to the body of scientific knowledge on renewable heat that the IEA has been supporting for over 40 years.

I am sure that the reader will find new knowledge and inspiring ideas for future-oriented hybrid heating systems based on renewables.

Werner Weiss

IEA SHC Chairman 2010–2014

Achieving high-performance or net-zero-energy buildings in terms of energy consumption and greenhouse gas (GHG) emissions requires the utilization of energy-efficient technologies and renewable energy technologies. The combination of heat pumps and solar energy is a very promising solution for achieving this goal. This technology is what the participants of Annex 38 and Task 44 of the IEA Heat Pump Programme and the Solar Heating and Cooling Implementing Agreements, respectively, have together been exploring. The study results are presented in this book, which is a valuable reference and a significant contribution to HVAC renewable energy systems applications.

Sophie Hosatte

IEA HPP Chairman 2005–2014

Acknowledgments

All participants in T44A38, the four subtask leaders, and the Operating Agent would like to express their gratitude to the following for the given opportunity of undertaking the scientific and technical work in this project:

The IEA Solar Heating and Cooling Programme Committee as well as the Heat Pump Programme Committee, and their secretariats, for accepting the theme of SHP as a research topic for an international collaboration, and partly financially supporting it.

All national institutional bodies that have financially supported the work of every team, namely, the energy ministries of most participating countries.

The industry partners that have worked with us and have understood that knowledge can be a necessary and durable asset for their business in the SHP field.

All national partners that have been in contact with participants of the T44A38 and provided information on ongoing SHC projects or simulation tools.

All owners of a house equipped with an SHP installation who have accepted the monitoring of their installation and the dissemination of results.

The three reviewers of the T44A38 reports and book, Andras Eckmanns from Switzerland, Ken Guthrie from Australia, and Michele Zinzi from Italy, all three experts representing their country in the SHC Executive Committee.

The Operating Agent wants to thank all participants in T44A38 for their active work and the four subtask leaders and their assistants who have committed themselves to organize this international project and to write the very technical subtask reports and most part of this book.

May 2014Switzerland

Jean-Christophe HadornOperating Agent

1Introduction

Jean-Christophe Hadorn

1.1 The Scope

This book is about a hybrid technology called “solar and heat pump.” It is basically the combination of a solar system with a heat pump delivering heat to a building.

When the sun is shining, the collectors will be the primary source of energy for the domestic hot water preparation and for the space heating. Furthermore, the daily solar production can be stored for future use during a few days. When the sun is less abundant or when the solar storage is empty, the heat pump will take over the duty. The source of the primary low-energy “heat” for the heat pump to operate can be air, ground, or water from a river or an aquifer. A nice feature of the hybrid combination is that the solar collectors can also be used as the provider of the primary heat for the heat pump. The two components will then operate in the so-called serial mode.

This book will analyze the behavior of the main combinations of solar and heat pump, derive facts from practical projects, provide results from simulations and laboratory tests, and draw conclusions based on 4 years of activity of a collaborative project developed under the auspice of the International Energy Agency.

1.2 Who Should Read This Book?

This book is recommended to the HVAC (heating, ventilation, and air conditioning) industry, the HVAC engineers and students, energy systems designers and planners, architects, energy politicians, manufacturers of solar energy components, manufacturers of heat pumps, standardization bodies, heating equipment distributors, and researchers in HVAC and building systems.

1.3 Why This Book?

Producing heat from solar energy is an established technology since the 1990s.

The heat pump technology known since 1930 is becoming a standard solution to heat buildings and prepare domestic hot water in many countries. Both markets have shown growth since 2000, especially the heat pump market noticeably in countries with a high share of hydroelectricity in their energy supply.

For some years, systems that combine solar thermal technology and heat pumps have been marketed to provide space heating and to produce domestic hot water. The energy prices, the need to reduce the overall electricity demand or the strategy to move to more efficient solutions for heating than the current ones, the European Union legislation, and future scenarios calling for more renewable energies have driven the change.

A strong initial development of combination of solar and heat pump started some years ago with the help of early work from industry and research bodies in a few European countries. Innovative companies have shown success stories in this early period and continue to promote the advantages of solar and heat pump combinations based on real experience.

The IEA Solar Heating and Cooling Program (SHC) launched in 2010 a 4-year project called Task 44, “solar and heat pump systems.” This was a joint effort with the IEA Heat Pump Program (HPP) under the name “Annex 38” to contribute to a better understanding of SHP (for “solar and heat pump”) systems.

This book presents the state of the art of the combined technology of solar collectors and electrical heat pumps based on the work undertaken within the Task 44 and Annex 38 project called T44A38 throughout this book. More than 50 participants from 13 countries have contributed to the collaborative effort over the 4 years of this international project.

It is anticipated that the electricity cost will increase on the planet in the future, due to CO2 cost considerations and scarcity of energy resources. Solar photovoltaics might change the picture if the technology is massively adopted. But still, highly efficient heat pumps reducing the electricity demand will be needed to substitute the fossil heating solutions that dominate the world energy market in the 2010s. Combinations with solar collectors can increase the overall performance of a heat pump and will therefore also be an elegant solution of choice.

There are scientific and technological issues in integrating solar collectors and heat pump machines. The complexity lies in having two variable sources that should work together optimally. Heat storage management and control strategies are also of prime importance for optimal design. This book will present the challenges and some solutions on all aspects.

T44A38 has concentrated its efforts on electrically driven heat pumps, not because other techniques such as sorption machines are not possible but because no participants in this international activity presented a project with a thermally driven machine.

1.4 What You Will Learn Reading This Book?

This book deals with

– heating systems;

– heat distribution by water-based systems (e.g., radiators and floor heating systems);

– small-scale systems, one-family house to small dwellings (5–100 kW);

– electrically driven heat pumps;

– residential houses; and

– new buildings and buildings to be renovated.

You will understand that SHP systems are complex systems that need careful design and optimal integration.

You will learn that good combinations of solar and heat pump can be achieved when the application is correctly done in adapted conditions. Examples are shown and discussed.

You will discover which definitions for the seasonal performance factor (

SPF

) of an installation are recommended for a comparison of heating solutions, for the assessment of technologies, for an environmental analysis, or for some economical considerations.

You will be able to classify all kinds of SHP systems in a new systematic way using the T44A38 “energy flow chart” diagram that you can use further to represent any kind of energy system.

You will see the advantages of different combinations of SHP found on the market and be able to challenge the vendor on the system design and performance.

You will learn that detailed simulation tools exist and a special framework to simulate SHP systems is available on the T44A38 web site.

You will understand which energy flows you should monitor in a project or in the laboratory and what SPF you can reasonably expect.

You will have the tools to assess the energy and economical benefits and other qualitative benefits that you can get out of a combination of SHP.

You will have a tool to evaluate the cost of the delivered heat of an SHP and what CO

2

reduction can be expected if you succeed to increase the SHP performance.

The logical organization of this book is the following:

–

Part One: Theoretical considerations.

Chapter 2 will tell you how the SHP systems found on the market in 2010–2012 can be classified in a systematic way thanks to the collaboration of more than 80 SHP companies.

Chapter 3 explains the theory behind the main components that you will find in an SHP system: the collector, the storage tank, the borehole, and the heat pump.

Chapter 4 presents all definitions of the performances of a complex system such as the coefficient of performance (COP) and all kinds of the SPF depending on the boundaries considered, and explains which should be used for which purpose.

Chapter 5 reviews the methods to test SHP systems in a laboratory so that prototypes or commercial products can be characterized and even further optimized.

–

Part Two: Practical considerations.

Chapter 6 presents the basics of monitoring SHP systems and recommends the best practice in data acquisition of SHP systems. Results of relevant systems monitored in situ are presented.

Chapter 7 shows how to simulate SHP systems with the T44A38 framework. It also presents important results on SHP combinations and sensitivity analyses. The benefit of a solar system in SHP is also quantitatively assessed through simulations.

Chapter 8 provides an interesting approach to evaluate the cost of an SHP system that can be compared with a classical or non-solar system. What brings solar system to a heat pump is quantitatively evaluated and qualitative criteria are listed according to the numerous experts in T44A38 along the 4-year work.

Complementing this book, the web site of T44A38 provides all appendices. The simulation framework is, for example, downloadable as well as all other documents produced during the course of T44A38 and papers or contributions from T44A38 experts at scientific conferences.

Enjoy!

Internet Sources

task44.iea-shc.org/publications

http://www.heatpumpcentre.org/en/projects/ongoingprojects/annex38

www.iea-shc.org/

www.heatpumpcentre.org/

www.ehpa.org/

www.estif.org/

www.rhc-platform.org

Part OneTheoretical Considerations

2System Description, Categorization, and Comparison

Jörn Ruschenburg and Sebastian Herkel

Summary

In the first step, several ways to analyze and categorize solar and heat pump (SHP) systems are presented. A graphical tool is introduced for visualizing the essence of different system concepts. The main criteria for analysis and categorization are found on component level (characteristics of solar collectors, heat pump, sizing, etc.) as well as on system level. For example, systems may cover space heating, domestic hot water (DHW) generation, and even space cooling – possibly but not necessarily more than just one of these functions. A system categorization approach is introduced – featuring parallel, series, and regenerative interactions between solar collectors and heat pump – that is applied throughout this book.

The precondition for defining performance figures and test methods for solar and heat pump systems (see Chapter 4) is a review of the market-available systems, investigating the relevance of nonstandard components and configurations. Such a review is presented, conducted on international level and followed by analysis regarding technical solutions on both component level and system level. Within this survey, carried out by IEA SHC Task 44/Annex 38 participants from several countries, 128 market-available solar and heat pump systems were identified. Most companies offer “conventional” systems with flat-plate collectors for both space heating and preparation of DHW. Still, manifold alternatives and technological as well as market-specific particularities are found. For example, solutions with photovoltaic–thermal collectors or heat pump solutions with solar thermal energy as only source exist since years ago.

2.1 System Analysis and Categorization

The aim of this chapter is to present possible ways to analyze and categorize existing and even future solar and heat pump systems. There are five main criteria to describe a solar and heat pump system: (i) the type of heat demand to be served; (ii) the low-temperature heat source(s) of the heat pump; (iii) the form(s) of energy used to drive the system; (iv) the function and placement of storages in the system; and (v) the interactions between these components. In addition, the systems can be described by the type of components used, by the sizing of components, and by the control. Thus, the reader should be aware that there is no global way of categorization that could meet all demands.

2.1.1 Approaches and Principles

In the literature, various specifications are analyzed to describe or compare SHP systems [1]. Depending on the respective interests, independent authors focus on parameters that seldom coincide. The aspects chosen for the scope of this chapter and their usage by other authors are listed in Table 2.1.

Table 2.1 Examined parameters and their application in literature

Parameter

[2]

[3]

[4]

[5,6]

[1]

Provenance and distribution

x

System functions

x

x

x

x

System concept

x

x

x

x

Heat pump characteristics

x

x

x

x

Collector characteristics

x

x

Provenance and distribution are more organizational than technical parameters, though there might be, for example, climatic design influences when comparing North and South European systems. System functions include DHW preparation as well as space heating and cooling. A system concept is usually defined by the interaction of heat pump, collector, and storages (cf. Section 2.1.3). Heat pump and collector characteristics may refer to several properties discussed in the respective subsections.

The possibilities to set up categories are equally varied. For example, the systems can be described by the type of applied components such as flat-plate, unglazed, or evacuated tube collectors, or alternatively by the refrigerant used in the heat pump cycle. The behavior of SHP systems depends also on the location, on the sizing of the components, and on the control. So, the definition of categories is multifaceted and strongly influenced by its purpose.

In this chapter, a graphical representation is introduced to systematically analyze and compare solar and heat pump systems. Afterward, these examinations result in a categorization approach.

2.1.2 Graphical Representation of Solar and Heat Pump Systems

The visualization presented in this chapter, first published by Frank et al. [1], is similar to energy flow charts that are frequently used in building energy engineering. Instead of a whole building, it is the heating system that is illustrated centrally against white background, including energy-storing (blue objects) and energy-transforming components (orange objects). The analysis of many combined solar and heat pump systems resulted in the finding of five recurring components. They comprise collector, heat pump, and backup heater, complemented by storages, namely, one on the source side and one on the sink side of the heat pump. For these typical components, fixed positions are defined. Specifications such as the collector type may be chosen. As defined boundaries (gray background), environmental energy (green objects) enters the system from above, final or “to-be-purchased” energy – in case of electricity generating systems even “bidirectionally traded” energy – from the left side (dark gray objects), and useful energy such as DHW leaves to the right (red objects).

The information provided by the coloring is in any case an additional feature, that is, it is not essential for understanding. In theory, any heat losses would be shown leaving the system downward. However, because of the purely qualitative nature of the approach, component sizes, efficiencies, and so on are not shown, and thus no losses. A label for the manufacturer's and the concept's name is added in the lower left part.

The final step is the depiction of energy flows connecting certain components. In doing so, the figure is enhanced to become a qualitative energy flow chart. The line style refers to the carrier medium (water, brine, and refrigerant) or indicates driving energies such as solar irradiation, gas, or electricity. A simple example for a complete visualization is given by Figure 2.1.

Fig. 2.1 Introductory example for the visualization scheme

It has to be pointed out that all possible operational modes of one system (excluding defrosting) are shown simultaneously in one scheme. All components appearing in a particular system are depicted as filled and nonexistent components remain as shaded frames as placeholders for orientation and comparability purposes. This arrangement results in energy flows mostly in left-to-right and up-down directions, though, of course, exceptions of this rule are possible.

In Figure 2.2, the presented visualization scheme is applied to typical systems. Here, a simplified hydraulic scheme is used as well, ignoring details such as backup heating elements. The comparison between the figure parts gives an impression of the visualization method's capability.

Fig. 2.2 Simplified hydraulic schemes (left) and corresponding visualizations (right) of different solar and heat pump systems

2.1.3 Categorization

System concepts are defined by the way the heat pump and the solar subsystem interact. Introductory works about the topic are found in Refs [7,8]. The distinctions made in this book, fully described in Ref. [9], are shown below.

Collector and heat pump independently supply useful energy (space heating and/or DHW), usually via one or more storages. This configuration is denoted as parallel, independent from the heat pump's source(s).

The collector acts as a source of the heat pump, either as exclusive or as additional source, and either directly or via a buffer storage. This configuration is denoted as series.

The use of solar energy to warm the main source of the heat pump, in this case usually ground, is denoted as regenerative.

It is important to see that series and/or regenerative modes do not exclude each other within one system. Therefore, many system concepts are in fact combinations of these modes.

The regenerative approach – described in detail by Kjellson [10] and Meggers et al. [11] – could possibly be regarded as a subset of the series concept. There are conceptual and operational differences, though: The regenerative operation is usually applied to improve or at least to maintain the quality of the ground source for long timescales or merely to prevent solar collector stagnation. Consequently, regenerative operation usually occurs in summer, when highest solar availability and lowest heating demand concur, that is, when the heat pump is not in operation. Many systems were found on the market featuring a regenerative mode explicitly, partially without an intended series mode.

It has to be realized that parallel, series, and regenerative arrangements do not exclude each other within one system. Depending on the demand and the climatic conditions, system controllers and hydraulics may adopt more than just one of these approaches. The counting of all possible combinations – while ignoring permutations, redundancies, and the trivial case of “none” – results in seven options. The illustrative systems shown in Figure 2.2 shall be used to give examples. From top to bottom, a parallel, a parallel–series, and a parallel–series–regenerative system are shown. Cooling functions of SHP systems are not represented by this approach, though they might provide regenerative effects as well.

This approach with its seven categories can be applied to all solar and heat pump systems known today, as shown in the following sections.

2.2 Statistical Analysis of Market-Available Solar Thermal and Heat Pump Systems

Numerous combinations of heat pumps and solar thermal collectors became market-ready over the last few years. It is evident, as shown in Section 2.2.2.1, that some systems entered the market much earlier, motivated by the oil crisis around 1979. An explicit and enduring trend developed just in the current century, though.

Regarding testing and assessing SHP systems, existing methods and standards are limited (cf. Chapter 4). The use of solar thermal energy as a source for heat pumps, for example, is ignored by today's national and international standards. The precondition for defining performance figures and test methods for SHP systems is a review of the market-available systems, investigating the relevance of nonstandard components and configurations. Such a review is presented within this chapter, conducted on international level and followed by analysis regarding technical solutions on both component level and system level.

Earlier overviews of SHP systems were provided by Refs [2–5], identifying 5, 13, 19, and 25 systems, respectively. More recently, the work of Trojek and Augsten [5] was updated and confined to 19 systems by Berner [6]. A new approach – more international and more comprehensive – was launched within Task 44/Annex 38.

Intermediate results were presented by Ruschenburg et al. [9]. However, the companies analyzed at that time (September 2012) were rechecked in order to confine all analyses to those companies and products still existing and available in April 2014. All in all, the reviewed basis is now formed by 128 combined solar thermal and heat pump systems (minus 7), provided by 72 (also minus 7) companies from 11 countries. The methods and the results are presented in the following sections.

2.2.1 Methods

The presented and analyzed systems were surveyed between October 2011 and September 2012 by participants of T44A38. Companies were preferably searched and contacted by native speakers. Like all activities of T44A38, the market survey and the subsequent analyses are limited to SHP systems that are equipped with electrically driven compression heat pumps and designed for DHW preparation and/or residential space heating. Cooling functions are documented as supplementary information only.

In principle, any heat pump can be combined with any solar thermal collector. Therefore, only those companies were taken into account that genuinely provide at least one of the main components, that is, solar collector, heat pump, storage(s), and/or controller. Research projects were also ignored.

To ensure comparability, the characteristics of each SHP system were documented in a harmonized way on two-sided fact sheets, including data on the overall concept, hydraulics, dimensioning, and system control, as well as technical specifications mainly of the collector, heat pump, and storage(s). These documentations are found as online Annex on the T44A38 web page (task44.iea-shc.org).

Most data were derived from online or print sources, though personal contact to representatives of the companies could be established in most of the cases, enabling interviews. Anyhow, it is clear that the correctness of the retrieved information cannot be checked systematically and independently. Moreover, completeness cannot be claimed. The fact that the majority of identified companies originate from countries officially participating in T44A38 might possibly be explained by the barrier of language, resulting in certain (e.g., Asian) countries erroneously being underrepresented or even unrepresented.

It has to be noted that in the following analyses, all systems are treated equally, that is, without respecting the number of installations. Respecting the number of installations for each system would certainly lead to quite different results. The database is incomplete here, but when it comes to market penetration, most conventional approaches – those analogous to combinations of boilers and solar thermal collectors – outnumber the less classical configurations (cf. Section 2.2.2.3). Finally, it is pointed out that, due to imperfect data collection, the sample size is not necessarily constant throughout this chapter. From the 72 researched companies, for example, all appear in Figure 2.3 but only 56 in Figure 2.4. But as all figures are labeled with absolute numbers, the sample size can easily be calculated if desired.

Fig. 2.3 Surveyed companies by country (country-code labeling according to ISO 3166-1)

Fig. 2.4 Companies entering the market of solar and heat pump systems. (The oldest system offered by each company is used as the indicator, provided that it is still marketed today)

Certain surveyed aspects will not be examined here. The reason is that their application turned out to be most flexible, and thus hardly comparable, comprising

– additional heat generators, that is, backup components such as electric heating elements, gas-fueled boilers, or wood stoves, sometimes offered optionally and almost always diversified regarding type, number, and way of integration;

– storage characteristics, for example, number and function; separated storages for space heating and DHW can be chosen for most systems as well as combined storages; and

– the dimensioning of any components, for example, nominal heating capacity, collector area, and storage volume; these are too flexible to be specified for statistical analyses.

In the introduction of this chapter, it is implied that many companies offer more than one system. So, in conjunction with the discussion on parameters to be analyzed, the question arises which parameters are defined as being distinctive. Within the scope of the survey, either a different concept or a different source of the heat pump justifies a “distinguishable” system. This decision is to some extent arbitrary. Depending on the reader, the collector type or the refrigerant used within the heat pump might be regarded as more important, and a consideration of these aspects would unquestionably result in a multiple of “distinguishable” systems.

2.2.2 Results

2.2.2.1 Surveyed Companies

As can be seen in Figure 2.3, most of the surveyed companies are based in Germany (50%) or Austria (15%). A complete list is found online on the T44A38 web site. Only a minority of all companies, however, restrict their market to one or two countries. The strong majority distributes their systems in three or more specified countries, even beyond those already named below, for example, to Croatia or to Greece. Being available “in Europe” or “worldwide” was claimed less frequently.

Figure 2.4 shows that most companies entered the SHP market in recent years. It has to be noted that systems withdrawn from the market – before, during, and after the time the survey was conducted – are ignored. About 15 are known to the authors.

2.2.2.2 System Functions

The main functions for SHP systems, especially for residential applications, are space heating and the preparation of DHW. Figure 2.5 shows that both of these functions are featured in most cases. In contrast, few market-available systems are exclusively designed for DHW preparation. The fact that all Chinese systems and significant shares of the systems originating from the Mediterranean countries (France, Italy, and Spain) are included within the latter group is identified as a strong indicator for market-specific and climate-specific system layout. Regarding the technical design, these “DHW-only” systems can be divided into two groups: rooftop thermosyphon constructions backed up by an (air source) heat pump appear to be representative for China. In Europe, in contrast, storage and (often exhaust air) heat pumps are typically installed indoors as one integrated unit, with the condenser of the heat pump immersed in the storage tank or coiled around it.

Fig. 2.5 Surveyed systems by function

Space cooling functions were surveyed supplementary. Interestingly, more than half of the systems (59%) are capable of “active” cooling via heat pump operation and/or “passive” cooling via ground or water source without heat pump operation, also known as “free,” “natural,” or “geo” cooling. As seen in Figure 2.5, this applies only to systems that already offer space heating. Some manufacturers offer all of their heat pump products with integrated cooling function by default.

It appears that air/air heat pumps, as popular as they might be for residential cooling and sometimes also heating purposes, are not combined with solar thermal systems. Instead, hydronic heat distribution is applied without exception. Here, floor heating systems are repeatedly recommended though rarely defined as mandatory.

As to the DHW preparation, modern hygienic approaches are found to be popular, given by internal heat exchangers (20% of the systems), for example, corrugated pipes, by external fresh water stations (23%), or by either solution to be selected (additional 6%). Austrian companies offer such technologies much above average.

2.2.2.3 System Concepts

At this point, the system concepts as described in Section 2.1.3 are applied to the reviewed systems. The result is a fragmentation shown in Figure 2.6.

Fig. 2.6 Surveyed systems by concept (P: parallel; S: series; R: regenerative)

The “parallel-only” concept, which is simpler in design, installation, and control, clearly dominates (63%). SHP systems with “series-only” concepts (6%) or “regenerative-only” concepts (1%) are rare. Most impressively, concepts with any combination of parallel, series, and/or regenerative modes amount to no less than 30%.

2.2.2.4 Heat Pump Characteristics – Heat Sources

Leaving aside air/air heat pumps mainly used for space cooling in Mediterranean countries, it can be said that ambient air and ground are the most common sources for heat pump installations in Europe, while water and exhaust air cover smaller shares [12]. Though not recorded by such statistics, Figure 2.6 demonstrates that energy converted by solar collectors is repeatedly utilized as a source, that is, the series concept and its variations. It becomes clear that even the “series-only” concept allows other possible sources within the same system.

Regarding the classical sources, Figure 2.7 illustrates that either pure air source or pure ground source heat pumps together are applied in half of the surveyed systems, namely, 27 and 24%, respectively. Water (9%) or exhaust air (6%) are utilized as a source in a few systems. Commercial SHP systems with wastewater or other sources appear untraceable.

Fig. 2.7 Surveyed systems by source

Systems using solar energy as the sole source amount to 6%. For a further 21%, solar energy is used in addition to other conventional sources (air, ground, or water). Such multisource systems require technical solutions that can be split into two groups, external and internal ones. The former refers to modified hydraulics between solar subsystem and heat pump, for example, by heat exchangers between solar loop and ground source loop or even by joint brine loops. Thus, conventional heat pumps and solar collectors can be used. The latter means that either the heat pump or the solar collectors are specifically designed to be integrated within series SHP systems. Though this approach is rare, offered by not more than six companies, it comprises the most alternative solutions, including

– multisource evaporators (two evaporators within one refrigerant cycle);

– directly evaporating solar collectors (with refrigerant as circulating fluid for the solar loop); and

– hybrid collectors (the solar thermal collectors include also the ambient air unit with integrated fan or other “active” technology).

2.2.2.5 Collector Types

Within the conducted survey, the collector type was chosen as the most significant parameter to compare the applied solar subsystem. The results are shown in Figure 2.8. Questions on additional characteristics – for example, regarding the circulating fluid, material, operational modes, Solar Keymark certification, or handling of stagnation – were answered incomprehensively; thus, these parameters cannot be presented in comparative form.

Fig. 2.8 Surveyed systems by collector type

Flat-plate collectors (FPCs) are stipulated in nearly half of the systems (48%), whereas evacuated tube collectors (ETCs) are essential only in the fewest cases (2%). Instead, the choice between these two types is frequently left open, that is, affected by the conditions on site as well as the preferences of client and installer (38%). Uncovered or unglazed collectors (UCs) are found repeatedly (6%), mainly in specific applications (cf. Section 2.2.2.6). Recently developed PVT collectors are found only in few market-available SHP systems (5%), according to this survey for the first time in 2011.

2.2.2.6 Cross Analysis Between Collector Type and System Concept

When compared with flat-plate and evacuated tube collectors, photovoltaic–thermal and unglazed collectors are efficient only at low temperatures and thus inefficient for space heating and even more when temperatures sufficient for DHW preparation are to be met. The source temperature of heat pumps is by definition too low to be used directly for heating purposes, though desired to be as high as possible – given the conditions at site – to increase the heat pump's efficiency. The logical reasoning out of these observations would be that, if installed within SHP systems, UCs and PVT collectors are preferably applied to concepts with series and/or regenerative character while FPCs and ETCs are favored for parallel concepts.

The acquired data (cf. Figures 2.6 and 2.8) allow verification by means of correlation. Figure 2.9 is a bubble plot with discrete values in all dimensions. The area of each bubble is proportional to the number of respective systems.

Fig. 2.9 Surveyed systems correlated by collector type and system concept (P: parallel; S: series; R: regenerative; FPC: flat-plate collector; ETC: evacuated tube collector; UC: unglazed collector; PVT: photovoltaic–thermal collector)