Solar Combisystems Promotion and Standardisation Final report Created by: Philippe Papillon Staff member of CEA-INES Contributions from Jan Erik Nielsen (PlanEnergi), Xavier Cholin, Thomas Letz (INES Education), Alexander Thür, Gabrielle Kuhness (AEE INTEC) Chris Bales (SERC) Philippe Papillon, Mickael Albaric (CEA-INES) Barbara Mette, Jens Ullmann, Harald Drueck (ITW) (2010) Date 12/20/2010 Version Final Revision 2 The sole responsibility for the content of this publication lies with the authors. It does not necessarily reflect the opinion of the European Union. Neither the EACI nor the European Commission are responsible for any use that may be made of the information contained therein. CONTENTS Symbol list ............................................................................................................................... 5 Table list .................................................................................................................................. 6 Figure list................................................................................................................................. 6 Introduction ............................................................................................................................. 9 1 Potential of solar combisystems ....................................................................................... 10 2 Typical solar combisystem................................................................................................ 14 2.1 Different hydraulic schemes...................................................................................................14 2.1.1 Domestic Hot Water Preparation............................................................................................................15 2.1.2 Auxiliary energy and its integration in a solar combisystems .................................................................17 2.1.3 Typical solar loops ...................................................................................................................................18 2.2 Products and tendencies........................................................................................................20 2.2.1 Prefabricated component groups ...........................................................................................................20 2.2.2 Compact prefabricated systems..............................................................................................................21 3 Qualitative inspection ...................................................................................................... 23 3.1 Procedure..............................................................................................................................23 3.2 Main results ..........................................................................................................................25 3.2.1 Overall System.........................................................................................................................................25 3.2.2 Solar Loop................................................................................................................................................26 3.2.3 Heat Storage............................................................................................................................................31 3.2.4 Space Heating..........................................................................................................................................34 3.2.5 Domestic Hot Water................................................................................................................................36 3.2.6 Auxiliary Heater.......................................................................................................................................37 3.3 Conclusion.............................................................................................................................38 4 In-Situ Monitoring of solar combisystems......................................................................... 40 4.1 Procedure..............................................................................................................................40 4.2 Monitoring equipment ..........................................................................................................42 4.3 Presentation of monitored systems........................................................................................42 4.4 Main results ..........................................................................................................................45 4.4.1 Results sorted by country........................................................................................................................46 4.4.2 Results sorted by manufacturer..............................................................................................................46 4.4.3 Results sorted by system type.................................................................................................................47 4.4.4 Analysis of thermal losses and solar gains ..............................................................................................47 4.4.5 Analysis of parasitic electricity ................................................................................................................48 4.4.6 Comparison between compact systems and systems assembled on site...............................................48 4.5 Comparison between laboratory tests and on site monitoring ................................................49 4.6 Outcomes..............................................................................................................................51 5 Test methods ................................................................................................................... 52 5.1 CTSS method .........................................................................................................................52 5.2 SCSPT method .......................................................................................................................53 CombiSol :Solar Combisystems Promotion and Standardisation page 2 5.3 Comparison of test methods..................................................................................................53 5.3.1 System design of the solar combisystems investigated ..........................................................................54 5.3.2 Quantities characterizing the thermal performance of a thermal solar system.....................................55 5.3.3 Test results of the CTSS method and SCSPT method ..............................................................................56 5.3.4 Adaption of the CTSS method to the boundary condition of the SCSPT method ...................................57 5.4 Performance prediction for different boundary conditions .....................................................59 5.5 Summary and conclusion .......................................................................................................60 6 Main recommendations for an efficient solar combi-systems............................................ 63 6.1 Overall System Concept.........................................................................................................63 6.2 Single or Multi Store Concepts ...............................................................................................64 6.3 Heat Storage .........................................................................................................................65 6.3.1 System with two heat storages: ..............................................................................................................66 6.3.2 Connection of space heating return pipe:...............................................................................................67 6.4 Auxiliary Heater.....................................................................................................................67 6.4.1 Problem of over-dimensioned auxiliary heater:......................................................................................67 6.4.2 Typical specific problems in auxiliary type 1 systems “auxiliary boiler as return flow increase”: ..........67 6.4.3 Typical problem of auxiliary volume as hydraulic switch:.......................................................................68 6.4.4 Auxiliary heater flow rate setting or control:..........................................................................................69 6.4.5 How to control the space heating auxiliary volume:...............................................................................69 6.4.6 Potentials for keeping heat storage small and avoid multi store systems:.............................................70 6.5 Space Heating........................................................................................................................71 6.5.1 High temperature space heating systems...............................................................................................72 6.5.2 Medium temperature space heating systems.........................................................................................72 6.5.3 Low temperature space heating systems................................................................................................73 6.5.4 How to achieve low return temperatures in practice: ............................................................................73