Solar District Heating with Seasonal Thermal Energy Storage in Germany Dipl.-Ing. Thomas Pauschinger Steinbeis Research Institute for Solar and Sustainable Thermal Energy Systems Meitnerstr. 8 70563 Stuttgart, Germany
Solar District Heating with Seasonal Thermal Energy Storage Introduction National research programmes Pilot plants
Solites - Member of the Steinbeis Foundation: turnover in 2010 over 100 Mio Euro technology transfer, consultancy and research Concept- and project development of sustainable energy supply systems (heat, cold and electricity, high reduction of CO 2 -emissions) Comprehensive energy concepts for buildings (adjustment of architectural concept, thermal insulation, building services and RES) Advisor to different ministries and international organisations (IEA/ OECD, EU, GER) (R&D for large scale solar thermal systems, STES and RES) Surveyor for large scale solar thermal systems with STES Chairman of the German experts group on seasonal thermal energy Storage Member of several international experts groups (R&D for large scale solar thermal systems, STES and RES)
Background of scientific R+D 1992 2003: Solarthermie-2000 Part 3 part 3: Central Solar Heating Plants with Seasonal Storage (CSHPSS) Development of seasonal storage concepts Realisation of eight pilot plants 2004-2008: Solarthermie2000plus one central point: Seasonal Thermal Energy Storage (STES) for: solar waste heat cooling combined heating & cooling CHP, biomass etc. Since 2009: R+D programme for solar thermal systems and storages -> Fundamental: Funding of ca. 50 % of investment costs for solar system
System concept of a central solar heating plant with seasonal storage Target: solar fraction of total heat demand: 50 % Solar collectors Central heating plant District heating network Seasonal thermal energy storage (STES) Solar network
CSHPSS in Hamburg, 1996 (Source: Gockell)
Heat amount Solar fractions of solar thermal systems Solar fraction: 7 10 % 15 20 % ~ 50 % Solar irradiation Total heat demand Jan Feb Mar Apr May June July Aug Sep Oct Nov Dec Domestic hot water system (100 % solar in summer) Combisystem (hot water and space heating) Central Solar Heating Plant with Seasonal Storage
Seasonal Thermal Energy Storage (STES) Concepts Tank thermal energy storage (TTES) (60 to 80 kwh/m³) Pit thermal energy storage (PTES) (60 to 80 kwh/m³) Borehole thermal energy storage (BTES) (15 to 30 kwh/m³) Aquifer thermal energy storage (ATES) (30 to 40 kwh/m³)
The pilot plants from the programs Solarthermie-2000 / 2000plus (1) Hamburg (1996) 3.000 m² FPC 4.500 m³ Tank Friedrichshafen (1996) 4.050 m² FPC 12.000 m³ Tank Neckarsulm (1997) 5.300 m² FPC 63.300 m³ BTES Steinfurt (1998) 510 m² FPC 1.500 m³ Pit Rostock (2000) 1.000 m² FPC 20.000 m³ ATES Hannover (2000) 1.350 m² FPC 2.750 m³ Tank
The pilot plants from the programs Solarthermie-2000 / 2000plus (2) Chemnitz, 1st CS (2000) 540 m² VTC 8.000 m³ Pit Attenkirchen (2002) 800 m² FPC 500 + 9.350 m³ Tank + BTES Munich (2007) 2.900 m² FPC 5.700 m³ Tank Crailsheim (2008) 5.300 m² FPC 100 m³ + 480 m³ Buffer Tanks 37.500 m³ BTES Eggenstein (2008) 1.600 m² FPC 4.500 m³ Pit
The CSHPSS in Munich: installation of solar collectors, 2007 Start of operation: 2007 24.800 m² heated area (2.300 MWh/a) 2.900 m² solar collectors 5.700 m³ tank Solar fraction: 47 %* *simulation results ZAE
Site plan solar collectors on buildings buildings without solar collectors thermal energy storage central heating plant heat transfer substations in buildings solar network local heat distribution network
Construction of the seasonal heat storage in Munich, 5700 m³, 2007
The CSHPSS in Crailsheim service area: 260 apartments, school, gym. heat demand: 4.100 MWh/year solar collectors: 7.300 m² (aperture) buffer storage: 100 + 480 m³ (water tank) STES: 37.500 m³ (BTES) el. heat pump: 530 kw solar fraction: 50 % (design) solar heat cost: 19 Euro-Cent/kWh
Solar collector fields in Crailsheim (Source: Stadtwerke Crailsheim)
BTES in Crailsheim, 37.500 m³, 2008
Investment cost per m³ water equivalent [ /m³] Investment cost of seasonal thermal energy storages 500 450 400 350 Ilmenau Crailsheim Aquifer Rottweil Steinfurt (K/W) realised study Tanks Pits BTES ATES 300 Kettmannhausen 250 200 Stuttgart Hanover Hamburg (HW) Bielefeld 150 Eggenstein Munich Berlin-Biesdorf 100 50 0 Chemnitz (K/W) Neckarsulm (1. phase) Rostock 100 1,000 10,000 100,000 Storage volume in water equivalent [m³] Friedrichshafen (HW) Crailsheim Aquifer Potsdam
Economics of solar thermal systems
Outlook: R&D-targets for STES Materials and wall constructions for combined thermal and pressure stress (>100 C water / steam) Two fields of developments: Large scale storages above 1.000 m³ Buffer storages between 100 und 500 m³. Improved reliability of storages Multi-functionality (heat sources, long-term / short-term etc.) Optimisation on total system level Comprehensive design and realisation process Target 2020: The first technologies of seasonal thermal energy storage for high solar fractions and excess heat storage are ready for the market.
Contact and Support Project website: www.solar-district-heating.eu Coordinator: Solites Dipl.- Ing. Thomas Pauschinger pauschinger@solites.de Supported by: The sole responsibility for the content of this document lies with the authors. It does not necessarily reflect the opinion of the funding authorities. The funding authorities are not responsible for any use that may be made of the information contained therein.