Edited byJean-Christophe Hadorn

Solar and Heat Pump Systemsfor Residential Buildings

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Edited byJean-Christophe Hadorn

Solar and Heat Pump Systemsfor Residential Buildings

Editor

Jean-Christophe HadornBASE Consultants SA8 rue du Nant1211 Geneve 6Switzerland

Cover: The cover photo shows selectiveunglazed collectors in Vouvry (CH).(Photo by O. Graf, Energie SolaireSA Switzerland)

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Contents

About the editor and the supervisors ..................................... IXList of contributors ................................................................... XIIEA solar heating and cooling programme............................. XVForewords.................................................................................. XVIIAcknowledgments .................................................................... XIX

1 Introduction.................................................................................... 11.1 The scope ............................................................................................ 11.2 Who should read this book?................................................................ 11.3 Why this book? ................................................................................... 11.4 What you will learn reading this book?............................................... 2

Internet sources ................................................................................... 4

Part OneTheoretical Considerations..................................................................... 5

2 System description, categorization, and comparison............... 72.1 System analysis and categorization..................................................... 72.1.1 Approaches and principles .................................................................. 72.1.2 Graphical representation of solar and heat pump systems................... 82.1.3 Categorization ..................................................................................... 92.2 Statistical analysis of market-available solar thermal and heat

pump systems...................................................................................... 112.2.1 Methods .............................................................................................. 122.2.2 Results................................................................................................. 142.2.2.1 Surveyed companies ........................................................................... 142.2.2.2 System functions................................................................................. 142.2.2.3 System concepts.................................................................................. 152.2.2.4 Heat pump characteristics – heat sources ............................................ 152.2.2.5 Collector types .................................................................................... 172.2.2.6 Cross analysis between collector type and system concept................. 182.3 Conclusions and outlook..................................................................... 192.4 Relevance and market penetration – illustrated with the example

of Germany ......................................................................................... 19References........................................................................................... 21

3 Components and thermodynamic aspects ................................ 233.1 Solar collectors.................................................................................... 233.2 Heat pumps ......................................................................................... 283.3 Ground heat exchangers...................................................................... 343.3.1 Modeling of vertical ground heat exchangers ..................................... 383.3.2 Modeling of horizontal ground heat exchangers ................................. 403.3.3 Combining GHX with solar collectors................................................ 413.4 Storage ................................................................................................ 42

V

3.4.1 Sensible heat storage and storage in general ....................................... 423.4.2 Latent storage...................................................................................... 453.4.3 Thermochemical reactions and sorption storage ................................. 463.5 Special aspects of combined solar and heat pump systems................. 473.5.1 Parallel versus series collector heat use............................................... 473.5.2 Exergetic efficiency and storage stratification..................................... 50

References........................................................................................... 52

4 Performance and its assessment ................................................ 634.1 Introduction......................................................................................... 634.2 Definition of performance figures ....................................................... 654.2.1 Overview of performance figures in current normative documents .... 654.2.1.1 Heat pumps ......................................................................................... 664.2.1.2 Solar thermal collectors....................................................................... 674.2.2 Solar and heat pump systems .............................................................. 674.2.3 Efficiency and performance figures..................................................... 684.2.4 Component performance figures ......................................................... 704.2.4.1 Coefficient of performance ................................................................. 704.2.4.2 Seasonal coefficient of performance ................................................... 704.2.4.3 Solar collector efficiency..................................................................... 714.2.5 System performance figures................................................................ 714.2.5.1 Seasonal performance factor ............................................................... 714.2.6 Other performance figures................................................................... 724.2.6.1 Solar fraction....................................................................................... 724.2.6.2 Renewable heat fraction...................................................................... 744.2.6.3 Fractional energy savings.................................................................... 744.3 Reference system and system boundaries ........................................... 754.3.1 Reference SHP system ........................................................................ 754.3.2 Definition of system boundaries and corresponding seasonal

performance factors............................................................................. 774.4 Environmental evaluation of SHP systems ......................................... 874.4.1.1 Primary energy ratio............................................................................ 904.4.1.2 Equivalent warming impact ................................................................ 914.4.1.3 Fractional primary energy savings ...................................................... 914.4.1.4 Fractional CO2 emission savings ........................................................ 914.5 Calculation example............................................................................ 91

Appendix 4.A Reviewed standards and other normativedocuments ........................................................................................... 97References........................................................................................... 102

5 Laboratory test procedures for solar and heatpump systems ............................................................................... 103

5.1 Introduction......................................................................................... 1045.2 Component testing and whole system testing ..................................... 1065.2.1 Testing boundary and implications on the test procedures.................. 1065.2.2 Direct comparison of CTSS and WST ................................................ 109

VI Contents

5.2.3 Applicability to SHP systems.............................................................. 1125.2.4 Test sequences and determination of annual performance .................. 1155.2.4.1 Direct extrapolation of results (WST for combi-systems)................... 1165.2.4.2 Modeling and simulation .................................................................... 1175.2.5 Output ................................................................................................. 1195.3 Experience from laboratory testing ..................................................... 1205.3.1 Extension of CTSS test procedure toward solar and heat

pump systems...................................................................................... 1205.3.2 Results of whole system testing of solar and heat pump systems ....... 1215.3.2.1 Excessive charging of the DHW zone................................................. 1235.3.2.2 Exergetic losses in general .................................................................. 1235.3.3 Extension of DST test procedure toward solar and heat

pump systems...................................................................................... 1235.4 Summary and findings ........................................................................ 126

References........................................................................................... 128

Part TwoPractical Considerations......................................................................... 131

6 Monitoring ...................................................................................... 1336.1 Background......................................................................................... 1336.2 Monitoring technique.......................................................................... 1346.2.1 Monitoring approach........................................................................... 1346.2.2 Measurement technology .................................................................... 1376.2.2.1 Data logging systems .......................................................................... 1376.2.2.2 Heat meters ......................................................................................... 1376.2.2.3 Electricity meters ................................................................................ 1386.2.2.4 Meteorological data............................................................................. 1396.2.2.5 Temperature sensors ........................................................................... 1396.3 Solar and heat pump performance – results from field tests ................ 1396.4 Best practice examples........................................................................ 1456.4.1 Blumberg ............................................................................................ 1456.4.2 Jona ..................................................................................................... 1476.4.3 Dreieich............................................................................................... 1496.4.4 Savièse ................................................................................................ 1526.4.5 Satigny ................................................................................................ 154

References........................................................................................... 157

7 System simulations....................................................................... 1597.1 Parallel solar and heat pump systems.................................................. 1597.1.1 Best practice for parallel solar and heat pump system concepts.......... 1617.1.2 Performance of parallel solar and heat pump systems......................... 1647.1.3 Performance in different climates and heat loads................................ 1667.1.4 Fractional energy savings and performance estimation with the

FSC method ........................................................................................ 1697.2 Series and dual-source concepts.......................................................... 171

Contents VII

7.2.1 Potential for parallel/series concepts with dual-source heat pump ...... 1717.2.2 Concepts with Ground Regeneration .................................................. 1737.2.3 Other series concepts: dual or single source........................................ 1777.2.4 Multifunctional concepts that include cooling .................................... 1837.3 Special collector designs in series systems.......................................... 1847.3.1 Direct expansion collectors ................................................................. 1847.3.2 Photovoltaic–thermal collectors.......................................................... 1847.3.3 Collector designs for using solar heat as well as ambient air .............. 1867.4 Solar thermal savings versus photovoltaic electricity production ....... 1877.5 Comparison of simulation results with similar boundary

conditions............................................................................................ 1887.5.1 Results for Strasbourg SFH45............................................................. 1897.5.1.1 Heat sources ........................................................................................ 1917.5.1.2 System classes..................................................................................... 1917.5.1.3 Dependence on collector size and additional effort............................. 1927.5.1.4 Electricity consumption ...................................................................... 1937.5.2 Results for Strasbourg SFH15 and SFH100........................................ 1957.5.3 Results for Davos SFH45.................................................................... 1967.6 Conclusions......................................................................................... 197

Appendix 7.A Appendix on simulation boundary conditions andplatform independence........................................................................ 199References........................................................................................... 204

8 Economic and market issues....................................................... 2098.1 Introduction......................................................................................... 2098.2 Advantages of SHP systems ............................................................... 2108.3 The economic calculation framework ................................................. 2118.4 A nomograph for economic analysis purposes.................................... 2168.5 Application to real case studies ........................................................... 219

References........................................................................................... 228

9 Conclusion and outlook ............................................................... 2299.1 Introduction......................................................................................... 2299.2 Components, systems, performance figures, and laboratory

testing.................................................................................................. 2299.3 Monitoring and simulation results and nontechnical aspects .............. 2319.4 Outlook ............................................................................................... 2339.4.1 Energy storage .................................................................................... 2339.4.2 System prefabrication ......................................................................... 2349.4.3 System quality testing ......................................................................... 2349.4.4 Further component development......................................................... 234

Glossary..................................................................................... 237

Index........................................................................................... 241

VIII Contents

About the editor and the supervisors

Editor

Jean-Christophe Hadorn started his career as a researcher onlarge-scale storage of solar heat in deep aquifers (1979–1981).Since several years, Mr. Hadorn has been appointed as ExternalManager of Thermal Solar Energy and Heat Storage ResearchProgram by the Swiss government. Mr. Hadorn was a participant inIEA SHC Task 7 on “Central Solar Heating Plants with SeasonalStorage” (1981–1985) and initiated Task 26 on “Solar Combisys-tems” (1996–2000). He was Operating Agent of Task 32 on “HeatStorage” (2003–2007). Since 2000, he leads an engineering com-

pany and designs solar thermal and PV plants. In 2010, he was chosen by aninternational committee of the IEA as the Operating Agent for the IEA SHC Task44 “Solar and Heat Pump Systems” also supported by the Heat Pump Programme underAnnex 38, project that produced this book.

Supervisors

Dr.Matteo D’Antoni is a senior researcher working at the Institutefor Renewable Energy of the European Academy of Bolzano(EURAC) in Italy. He is active in the development of hybridrenewable energy systems for residential and commercial applica-tions and in the design of building integrated solar thermal tech-nologies. He is an expert in numerical calculus and transientsimulation of energy systems. He managed EU funded and industrycommissioned projects. Dr. D’Antoni lectures designers on thetopic of renewable energy sources and energy system simulations.

Dr. Michel Y. Haller is Head of Research at the Institut fürSolartechnik SPF at the University of Applied Sciences HSR inSwitzerland. He holds a title of Master in Environmental Sciencesof ETH Zürich, and obtained his doctoral degree in engineering atGraz University of Technology. He is coordinator of the EU projectMacSheep, and author of more than 50 refereed papers. Dr. Hallerwas leader of the Subtask C “Modelling and Simulation” of the IEASHC Task 44/HPP Annex 38 on “Solar and Heat Pump Systems.”

IX

Sebastian Herkel is a senior researcher at the Fraunhofer Institutefor Solar Energy Systems ISE in Freiburg, Germany and Head ofSolar Buildings Department. He is a researcher working in appliedresearch in building energy performance and renewable energysystems. His focus is on integral energy concepts for buildings andneighborhoods, scientific analysis of building performance, andtechnologies for integration of renewable energy in buildings.

Ivan Malenkovic is a researcher at the Fraunhofer Institute forSolar EnergySystems ISEwith over 10years of experience inR&D,testing, and standardization in the field of heat pumping technol-ogies. He is currently responsible for the ServiceLab for perform-ance evaluation within the Competence Centre for Heat Pumps andChillers at ISE. He participated in a number of IEA SHC and HPPTasks 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 articlespublished in conference proceedings and reviewed journals.

Christian Schmidt is a researcher at the TestLab Solar ThermalSystems at Fraunhofer Institute for Solar Energy Systems ISE(2009–2014). Currently, he is pursuing a Ph.D. project that dealswith the further development of performance test methods formultivalent heat transformers used for heating and cooling ofbuildings. He completed his Masters of Science in RenewableEnergy and Energy Efficiency at University of Kassel in 2010. In2008, he received his Diploma in Mechanical Engineering fromFachhochschule Bingen, University of Applied Sciences.

Wolfram Sparber is Head of the Institute for Renewable Energy atEURAC Research since its foundation in 2005. One of the mainresearch areas of the Institute are sustainable heating and coolingsystems with several projects brought forward in the field of solarthermal systems combined with thermally or electrically driven heatpumps. Since 2011, Wolfram Sparber is Vice President of the boardof the European Technology Platform Renewable Heating andCooling with a focus on hybrid systems including several heatsources in one system. As well in 2011 he took over the presidencyof the board of SELAG, a regional energyutility focused on renewablepower production, energy distribution, and district heating.

X About the editor and the supervisors

List of contributors

Thomas AfjeiFachhochschule Nordwestschweiz(FHNW)Institut Energie am Bau (IEBau)St. Jakobs-Strasse 844132 MuttenzSwitzerland

Chris BalesSolar Energy Research Center (SERC)School of Industrial Technology andBusiness StudiesHögskolan Dalarna791 88 FalunSweden

Erik BertramInstitut für SolarenergieforschungHameln (ISFH)Am Ohrberg 131860 EmmerthalGermany

Sebastian BonkUniversity of StuttgartInstitute for Thermodynamics andThermal Engineering (ITW)Pfaffenwaldring 670550 StuttgartGermany

Jacques BonyHaute Ecole d’Ingénierie et de Gestion duCanton de VaudLaboratoire d’Energétique Solaire et dePhysique du Bâtiment (LESBAT)Centre St-Rochav. des Sports 201400 Yverdon-les-BainsSwitzerland

Sunliang CaoAalto UniversitySchool of EngineeringDepartment of Energy TechnologyHVAC Technology00076 AaltoFinland

Daniel CarbonellHochschule für Technik HSRInstitut für Solartechnik SPFOberseestr. 108640 RapperswilSwitzerland

Maria João CarvalhoLaboratório Nacional de Energia eGeologia, I.P.Laboratório de Energia SolarEstrada do Paco do Lumiar 221649-038 LisbonPortugal

Matteo D’AntoniEURAC ResearchInstitute for Renewable EnergyViale Druso 139100 BolzanoItaly

Ralf DottFachhochschule Nordwestschweiz(FHNW)Institut Energie am Bau (IEBau)St. Jakobs-Strasse 844132 MuttenzSwitzerland

XI

Harald DrückUniversity of StuttgartInstitute for Thermodynamics andThermal Engineering (ITW)Pfaffenwaldring 670550 StuttgartGermany

Sara EicherHaute Ecole d’Ingénierie et de Gestion duCanton de VaudLaboratoire d’Energétique Solaire et dePhysique du Bâtiment (LESBAT)Centre St-Rochav. des Sports 201400 Yverdon-les-BainsSwitzerland

Jorge FacãoLaboratório Nacional de Energia eGeologia, I.P.Laboratório de Energia SolarEstrada do Paco do Lumiar 221649-038 LisbonPortugal

Roberto FedrizziEURAC ResearchInstitute for Renewable EnergyViale Druso 139100 BolzanoItaly

Carolina de Sousa FragaUniversity of GenevaInstitute for Environmental SciencesEnergy GroupBatelle Bat. D, Route de Drize 71227 CarougeSwitzerland

Robert HaberlHochschule für Technik HSRInstitut für Solartechnik SPFOberseestr. 108640 RapperswilSwitzerland

Jean-Christophe HadornBASE Consultants SA8 rue du Nant1207 GenevaSwitzerland

Michel Y. HallerHochschule für Technik HSRInstitut für Solartechnik SPFOberseestr. 108640 RapperswilSwitzerland

Michael HartlAIT Austrian Institute of TechnologyEnergy DepartmentGiefinggasse 21210 ViennaAustria

Andreas HeinzTechnische Universität GrazInstitut für Wärmetechnik (IWT)Inffeldgasse 25/B8010 GrazAustria

Sebastian HerkelFraunhofer Institute for Solar EnergySystemsDivision of Thermal Systems andBuildingsHeidenhofstr. 279110 FreiburgGermany

XII List of contributors

Pierre HollmullerUniversity of GenevaInstitute for Environmental SciencesEnergy GroupBatelle Bat. D, Route de Drize 71227 CarougeSwitzerland

Anja LooseUniversity of StuttgartInstitute for Thermodynamics andThermal Engineering (ITW)Pfaffenwaldring 670550 StuttgartGermany

Ivan MalenkovicFraunhofer Institute for Solar EnergySystemsDivision of Thermal Systems andBuildingsHeidenhofstr. 279110 FreiburgGermanyandAIT Austrian Institute of TechnologyEnergy DepartmentGiefinggasse 21210 ViennaAustria

Floriane MermoudUniversity of GenevaInstitute for Environmental SciencesEnergy GroupBatelle Bat. D, Route de Drize 71227 CarougeSwitzerland

Marek MiaraFraunhofer Institute for Solar EnergySystemsDivision of Thermal Systems andBuildingsHeidenhofstr. 279110 FreiburgGermany

Fabian OchsUniversity of InnsbruckUnit for Energy Efficient BuildingsTechnikerstrasse 136020 InnsbruckAustria

Peter PärischInstitut für SolarenergieforschungHameln (ISFH)Am Ohrberg 131860 EmmerthalGermany

Bengt PerersTechnical University of DenmarkDTU Civil Engineering DK & SERCSwedenBrovej, Building 1182800 Kgs. LyngbyDenmark

Jörn RuschenburgFraunhofer Institute for Solar EnergySystemsDivision of Thermal Systems andBuildingsHeidenhofstr. 279110 FreiburgGermany

Christian SchmidtFraunhofer Institute for Solar EnergySystemsDivision of Thermal Systems andBuildingsHeidenhofstr. 279110 FreiburgGermany

Kai SirenAalto UniversitySchool of EngineeringDepartment of Energy TechnologyHVAC Technology00076 AaltoFinland

List of contributors XIII

Wolfram SparberEURAC ResearchInstitute for Renewable EnergyViale Druso 139100 BolzanoItaly

Bernard ThissenEnergie Solaire SARue des Sablons 83960 SierreSwitzerland

Alexander ThürUniversität InnsbruckInstitut für Konstruktion undMaterialwissenschaftenAB Enrgieeffizientes BauenTechnikerstr. 19a6020 InnsbruckAustria

Martin VukitsAEE – Institut für NachhaltigeTechnologienFeldgasse 198200 GleisdorfAustria

XIV List of contributors

IEA solar heating and cooling programme

The Solar Heating and Cooling Programme was founded in 1977 as one of the firstmultilateral technology initiatives (“Implementing Agreements”) of the InternationalEnergy Agency. Its mission is to “advance international collaborative efforts for solarenergy to reach the goal set in the vision of contributing 50% of the low temperatureheating 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 forsolar 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 andCooling (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 ofUnderstanding with solar thermal trade organizations, statistics collection and analysis,conferences, and workshops – have been undertaken. An annual international confer-ence 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

AustraliaAustriaBelgiumCanadaChinaDenmarkECREEEEuropean CommissionEuropean Copper Institute

GermanyGulf Organization forResearch andDevelopment

FranceItalyMexicoNorwayPortugal

RCREEESingaporeSouth AfricaSpainSwedenSwitzerlandThe NetherlandsTurkeyUnited Kingdom

Further information

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

XV

Forewords

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

In future, we need to develop hybrid systems that offer a complete heating system basedon 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 itpresents the path to high-performance hybrid systems.

The book is the result of a collaborative international work within the Solar Heating andCooling 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 ExecutiveCommittee, to introduce this book.

The international work has led to some interesting findings on solar and heat pumpcombinations based on monitored data and the use of simulation. The book presents allthese findings and the methodologies needed to assess the energy performance of suchcombinations. It is an important contribution to the body of scientific knowledge onrenewable 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-orientedhybrid heating systems based on renewables.

Werner WeissIEA SHC Chairman 2010–2014

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

Sophie HosatteIEA HPP Chairman 2005–2014

XVII

Acknowledgments

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

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

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

• The industry partners that have worked with us and have understood that knowledgecan 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 andprovided information on ongoing SHC projects or simulation tools.

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

• The three reviewers of the T44A38 reports and book, Andréas Eckmanns fromSwitzerland, Ken Guthrie from Australia, and Michele Zinzi from Italy, all threeexperts representing their country in the SHC Executive Committee.

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

May 2014 Jean-Christophe HadornSwitzerland Operating Agent

XIX

1 IntroductionJean-Christophe Hadorn

1.1 The scope

This book is about a hybrid technology called “solar and heat pump.” It is basically thecombination 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 thedomestic hot water preparation and for the space heating. Furthermore, the daily solarproduction can be stored for future use during a few days. When the sun is less abundantor when the solar storage is empty, the heat pump will take over the duty. The source ofthe primary low-energy “heat” for the heat pump to operate can be air, ground, or waterfrom a river or an aquifer. A nice feature of the hybrid combination is that the solarcollectors can also be used as the provider of the primary heat for the heat pump. The twocomponents 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 laboratorytests, and draw conclusions based on 4 years of activity of a collaborative projectdeveloped 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, manufacturersof heat pumps, standardization bodies, heating equipment distributors, and researchersin 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 heatbuildings and prepare domestic hot water in many countries. Both markets have showngrowth since 2000, especially the heat pump market noticeably in countries with a highshare of hydroelectricity in their energy supply.

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

A strong initial development of combination of solar and heat pump started some yearsago with the help of early work from industry and research bodies in a few European

Solar and Heat Pump Systems for Residential Buildings, First Edition.Edited by Jean-Christophe Hadorn.© 2015 Ernst & Sohn GmbH & Co. KG. Published 2015 by Ernst & Sohn GmbH & Co. KG.

1

countries. Innovative companies have shown success stories in this early period andcontinue to promote the advantages of solar and heat pump combinations based on realexperience.

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

This book presents the state of the art of the combined technology of solarcollectors and electrical heat pumps based on the work undertaken within the Task44 and Annex 38 project called T44A38 throughout this book. More than 50participants from 13 countries have contributed to the collaborative effort over the4 years of this international project.

It is anticipated that the electricity cost will increase on the planet in the future, due toCO2 cost considerations and scarcity of energy resources. Solar photovoltaics mightchange the picture if the technology is massively adopted. But still, highly efficient heatpumps reducing the electricity demand will be needed to substitute the fossil heatingsolutions that dominate the world energy market in the 2010s. Combinations with solarcollectors can increase the overall performance of a heat pump and will therefore also bean elegant solution of choice.

There are scientific and technological issues in integrating solar collectors and heatpump machines. The complexity lies in having two variable sources that should worktogether optimally. Heat storage management and control strategies are also of primeimportance for optimal design. This book will present the challenges and some solutionson all aspects.

T44A38 has concentrated its efforts on electrically driven heat pumps, not because othertechniques such as sorption machines are not possible but because no participants in thisinternational 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.

1. You will understand that SHP systems are complex systems that need careful designand optimal integration.

2 1 Introduction

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

3. You will discover which definitions for the seasonal performance factor (SPF) of aninstallation are recommended for a comparison of heating solutions, for the assess-ment of technologies, for an environmental analysis, or for some economicalconsiderations.

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

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

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

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

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

9. You will have a tool to evaluate the cost of the delivered heat of an SHP andwhat CO2 reduction can be expected if you succeed to increase the SHPperformance.

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 canbe classified in a systematic way thanks to the collaboration of more than 80 SHPcompanies.

Chapter 3 explains the theory behind the main components that you will find in anSHP 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 asthe coefficient of performance (COP) and all kinds of the SPF depending on theboundaries considered, and explains which should be used for which purpose.

Chapter 5 reviews the methods to test SHP systems in a laboratory so that prototypesor 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 bestpractice in data acquisition of SHP systems. Results of relevant systems monitoredin situ are presented.

Chapter 7 shows how to simulate SHP systems with the T44A38 framework. It alsopresents important results on SHP combinations and sensitivity analyses. The benefitof 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 thatcan be compared with a classical or non-solar system. What brings solar system to a

1.4 What you will learn reading this book? 3

heat pump is quantitatively evaluated and qualitative criteria are listed according tothe numerous experts in T44A38 along the 4-year work.

Complementing this book, the web site of T44A38 provides all appendices. Thesimulation framework is, for example, downloadable as well as all other documentsproduced during the course of T44A38 and papers or contributions from T44A38experts 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

4 1 Introduction

Part One

Theoretical Considerations

Solar and Heat Pump Systems for Residential Buildings, First Edition.Edited by Jean-Christophe Hadorn.© 2015 Ernst & Sohn GmbH & Co. KG. Published 2015 by Ernst & Sohn GmbH & Co. KG.

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